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Igel P, Fürst AE, Jackson MA. The prevalence of equine odontoclastic tooth resorption and hypercementosis and the role of interincisal angulation in disease severity in a representative cohort of horses in Switzerland. SCHWEIZ ARCH TIERH 2023; 165:564-572. [PMID: 37646096 DOI: doi.org/10.17236/sat00401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
INTRODUCTION Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is an increasingly diagnosed degenerative dental disease in aged horses. The primary aim of this retrospective study was to determine the prevalence of EOTRH in horses admitted to the Equine Hospital, University of Zurich, for dental procedures from 2004 to 2017. A secondary goal was to measure and compare interincisal angles on two-dimensional radiographs of horses with EOTRH to determine whether the interincisal angle is associated with age and severity of the disease. Radiographs were assessed for the presence of lysis and/or hypercementosis, and the number and position of the teeth affected were determined. Each tooth was also evaluated using the modified classification system introduced by Rehrl et al. (2018), in which stage 0 indicates no radiographic abnormalities and stage 3 denotes severe abnormalities. The overall stage was defined by the tooth with the most severe lesions. The interincisal angle was determined in horses that had suitable radiographs. The medical records of 838 horses admitted for dental procedures were evaluated, and 85 (10,1 %) had clinical evidence of EOTRH. The mean interincisal angle was 136,06 ° in horses with mild to moderate EOTRH and 135,10 ° (SD = 11,90 °) in severely affected patients. In conclusion, the angle measurements on lateral radiographs were highly reproducible. However, the interincisal angle was not associated with age or the severity of EOTRH. The interincisal angle and the disease pattern were not correlated.
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Affiliation(s)
- P Igel
- Equine Department, Vetsuisse Faculty, University of Zurich
| | - A E Fürst
- Equine Department, Vetsuisse Faculty, University of Zurich
| | - M A Jackson
- Equine Department, Vetsuisse Faculty, University of Zurich
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2
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Bedingfield SK, Colazo JM, Yu F, Liu DD, Jackson MA, Himmel LE, Cho H, Crofford LJ, Hasty KA, Duvall CL. Amelioration of post-traumatic osteoarthritis via nanoparticle depots delivering small interfering RNA to damaged cartilage. Nat Biomed Eng 2021; 5:1069-1083. [PMID: 34413494 PMCID: PMC8497446 DOI: 10.1038/s41551-021-00780-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/10/2021] [Indexed: 02/01/2023]
Abstract
The progression of osteoarthritis is associated with inflammation triggered by the enzymatic degradation of extracellular matrix in injured cartilage. Here we show that a locally injected depot of nanoparticles functionalized with an antibody targeting type II collagen and carrying small interfering RNA targeting the matrix metalloproteinase 13 gene (Mmp13), which breaks down type II collagen, substantially reduced the expression of MMP13 and protected cartilage integrity and overall joint structure in acute and severe mouse models of post-traumatic osteoarthritis. MMP13 inhibition suppressed clusters of genes associated with tissue restructuring, angiogenesis, innate immune responses and proteolysis. We also show that intra-articular injections of the nanoparticles led to greater reductions in disease progression than either a single injection or weekly injections of the steroid methylprednisolone. Sustained drug retention by targeting collagen in the damaged extracellular matrix of osteoarthritic cartilage may also be an effective strategy for the treatment of osteoarthritis with other disease-modifying drugs.
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Affiliation(s)
- Sean K. Bedingfield
- Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place PMB 351826 Nashville, TN 37235-1826
| | - Juan M. Colazo
- Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place PMB 351826 Nashville, TN 37235-1826
| | - Fang Yu
- Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place PMB 351826 Nashville, TN 37235-1826
| | - Danielle D. Liu
- Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place PMB 351826 Nashville, TN 37235-1826
| | - Meredith A. Jackson
- Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place PMB 351826 Nashville, TN 37235-1826
| | - Lauren E. Himmel
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, 1161 21st Ave. South, Suite C-3322 Nashville, Tennessee 37232-2561
| | - Hongsik Cho
- Department of Orthopaedic Surgery and Biomedical Engineering, Memphis VA Medical Center, 1211 Union Ave. Suite 520 Memphis, TN 38104
| | - Leslie J. Crofford
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, 1161 21st Ave. South, Suite C-3322 Nashville, Tennessee 37232-2561,Department of Medicine, Division of Rheumatology and Immunology, Vanderbilt University Medical Center, 1161 21st Ave S, Nashville, TN 37232
| | - Karen A. Hasty
- Department of Orthopaedic Surgery and Biomedical Engineering, Memphis VA Medical Center, 1211 Union Ave. Suite 520 Memphis, TN 38104
| | - Craig L. Duvall
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, 1161 21st Ave. South, Suite C-3322 Nashville, Tennessee 37232-2561,Correspondence and requests for materials should be addressed to C.L.D.
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3
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Jackson MA, Patel SS, Yu F, Cottam MA, Glass EB, Hoogenboezem EN, Fletcher RB, Dollinger BR, Patil P, Liu DD, Kelly IB, Bedingfield SK, King AR, Miles RE, Hasty AM, Giorgio TD, Duvall CL. Kupffer cell release of platelet activating factor drives dose limiting toxicities of nucleic acid nanocarriers. Biomaterials 2021; 268:120528. [PMID: 33285438 PMCID: PMC7856291 DOI: 10.1016/j.biomaterials.2020.120528] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/08/2020] [Accepted: 11/04/2020] [Indexed: 01/06/2023]
Abstract
This work establishes that Kupffer cell release of platelet activating factor (PAF), a lipidic molecule with pro-inflammatory and vasoactive signaling properties, dictates dose-limiting siRNA nanocarrier-associated toxicities. High-dose intravenous injection of siRNA-polymer nano-polyplexes (si-NPs) elicited acute, shock-like symptoms in mice, associated with increased plasma PAF and consequently reduced PAF acetylhydrolase (PAF-AH) activity. These symptoms were completely prevented by prophylactic PAF receptor inhibition or Kupffer cell depletion. Assessment of varied si-NP chemistries confirmed that toxicity level correlated to relative uptake of the carrier by liver Kupffer cells and that this toxicity mechanism is dependent on carrier endosome disruptive function. 4T1 tumor-bearing mice, which exhibit increased circulating leukocytes, displayed greater sensitivity to these toxicities. PAF-mediated toxicities were generalizable to commercial delivery reagent in vivo-jetPEI® and an MC3 lipid formulation matched to an FDA-approved nanomedicine. These collective results establish Kupffer cell release of PAF as a key mediator of siRNA nanocarrier toxicity and identify PAFR inhibition as an effective strategy to increase siRNA nanocarrier tolerated dose.
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Affiliation(s)
- Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Shrusti S Patel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Fang Yu
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Matthew A Cottam
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Evan B Glass
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Ella N Hoogenboezem
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - R Brock Fletcher
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Bryan R Dollinger
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Prarthana Patil
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Danielle D Liu
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Isom B Kelly
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Sean K Bedingfield
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Allyson R King
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Rachel E Miles
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Alyssa M Hasty
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA; Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, 37212, USA
| | - Todd D Giorgio
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
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Dave KM, Han L, Jackson MA, Kadlecik L, Duvall CL, S Manickam D. DNA Polyplexes of a Phosphorylcholine-Based Zwitterionic Polymer for Gene Delivery. Pharm Res 2020; 37:176. [PMID: 32860072 DOI: 10.1007/s11095-020-02899-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/28/2020] [Indexed: 01/15/2023]
Abstract
PURPOSE We tested polyplexes of a diblock polymer containing a pH-responsive, endosomolytic core (dimethylaminoethyl methacrylate and butyl methacrylate; DB) and a zwitterionic Poly (methacryloyloxyethyl phosphorylcholine) (PMPC) corona for the delivery of plasmid DNA (pDNA) to glioblastoma cells. METHODS We studied the physicochemical characteristics of the DNA polyplexes such as particle hydrodynamic diameter and surface potential. Cytocompatibility of free PMPC-DB polymer and pDNA polyplexes with U-87MG and U-138MG glioma cell lines were evaluated using the ATP assay. The transfection activity of luciferase pDNA polyplexes was measured using a standard luciferase assay. Anti-proliferative, apoptotic, and cell migration inhibitory activities of PMPC-DB/Interferon-beta (IFN-β1) pDNA polyplexes were examined using ATP assay, flow cytometry, and wound closure assay, respectively. RESULTS PMPC-DB copolymer condensed pDNA into nanosized polyplexes. DNA polyplexes showed particle diameters ranging from ca. 100-150 nm with narrow polydispersity indices and near electroneutral zeta potential values. PMPC-DB/Luciferase pDNA polyplexes were safe and showed an 18-fold increase in luciferase expression compared to the gold standard PEI polyplexes in U-87MG cells. PMPC-DB/IFN-β1 polyplexes induced apoptosis, demonstrated anti-proliferative effects, and retarded cell migration in glioblastoma cells. CONCLUSION The results described herein should guide the future optimization of PMPC-DB/DNA delivery systems for in vivo studies.
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Affiliation(s)
- Kandarp M Dave
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Linjiang Han
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232, USA
| | - Lindsay Kadlecik
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232, USA
| | - Devika S Manickam
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA.
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Kilchrist KV, Dimobi SC, Jackson MA, Evans BC, Werfel TA, Dailing EA, Bedingfield SK, Kelly IB, Duvall CL. Gal8 Visualization of Endosome Disruption Predicts Carrier-Mediated Biologic Drug Intracellular Bioavailability. ACS Nano 2019; 13:1136-1152. [PMID: 30629431 PMCID: PMC6995262 DOI: 10.1021/acsnano.8b05482] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Endolysosome entrapment is one of the key barriers to the therapeutic use of biologic drugs that act intracellularly. The screening of prospective nanoscale endosome-disrupting delivery technologies is currently limited by methods that are indirect and cumbersome. Here, we statistically validate Galectin 8 (Gal8) intracellular tracking as a superior approach that is direct, quantitative, and predictive of therapeutic cargo intracellular bioactivity through in vitro high-throughput screening and in vivo validation. Gal8 is a cytosolically dispersed protein that, when endosomes are disrupted, redistributes by binding to glycosylation moieties selectively located on the inner face of endosomal membranes. The quantitative redistribution of a Gal8 fluorescent fusion protein from the cytosol into endosomes is demonstrated as a real-time, live-cell assessment of endosomal integrity that does not require labeling or modification of either the carrier or the biologic drug and that allows quantitative distinction between closely related, endosome-disruptive drug carriers. Through screening two families of siRNA polymeric carrier compositions at varying dosages, we show that Gal8 endosomal recruitment correlates strongly ( r = 0.95 and p < 10-4) with intracellular siRNA bioactivity. Through this screen, we gathered insights into how composition and molecular weight affect endosome disruption activity of poly[(ethylene glycol)- b-[(2-(dimethylamino)ethyl methacrylate)- co-(butyl methacrylate)]] [PEG-(DMAEMA- co-BMA)] siRNA delivery systems. Additional studies showed that Gal8 recruitment predicts intracellular bioactivity better than current standard methods such as Lysotracker colocalization ( r = 0.35, not significant), pH-dependent hemolysis (not significant), or cellular uptake ( r = 0.73 and p < 10-3). Importantly, the Gal8 recruitment method is also amenable to fully objective high-throughput screening using automated image acquisition and quantitative image analysis, with a robust estimated Z' of 0.6 (whereas assays with Z' > 0 have high-throughput screening utility). Finally, we also provide measurements of in vivo endosomal disruption based on Gal8 visualization ( p < 0.03) of a nanocarrier formulation confirmed to produce significant cytosolic delivery and bioactivity of siRNA within tumors ( p < 0.02). In sum, this report establishes the utility of Gal8 subcellular tracking for the rapid optimization and high-throughput screening of the endosome disruption potency of intracellular delivery technologies.
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Affiliation(s)
- Kameron V. Kilchrist
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
| | - Somtochukwu C. Dimobi
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
| | - Meredith A. Jackson
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
| | - Brian C. Evans
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
| | | | - Eric A. Dailing
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
| | - Sean K. Bedingfield
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
| | - Isom B. Kelly
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
| | - Craig L. Duvall
- Department of Biomedical Engineering, Vanderbilt University, PMB 351634, Nashville, Tennessee 37235, United States
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Jackson MA, Bedingfield SK, Yu F, Stokan ME, Miles RE, Curvino EJ, Hoogenboezem EN, Bonami RH, Patel SS, Kendall PL, Giorgio TD, Duvall CL. Dual carrier-cargo hydrophobization and charge ratio optimization improve the systemic circulation and safety of zwitterionic nano-polyplexes. Biomaterials 2019; 192:245-259. [PMID: 30458360 PMCID: PMC6534819 DOI: 10.1016/j.biomaterials.2018.11.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 12/27/2022]
Abstract
While polymeric nano-formulations for RNAi therapeutics hold great promise for molecularly-targeted, personalized medicine, they possess significant systemic delivery challenges including rapid clearance from circulation and the potential for carrier-associated toxicity due to cationic polymer or lipid components. Herein, we evaluated the in vivo pharmacokinetic and safety impact of often-overlooked formulation parameters, including the ratio of carrier polymer to cargo siRNA and hydrophobic siRNA modification in combination with hydrophobic polymer components (dual hydrophobization). For these studies, we used nano-polyplexes (NPs) with well-shielded, zwitterionic coronas, resulting in various NP formulations of equivalent hydrodynamic size and neutral surface charge regardless of charge ratio. Doubling nano-polyplex charge ratio from 10 to 20 increased circulation half-life five-fold and pharmacokinetic area under the curve four-fold, but was also associated with increased liver enzymes, a marker of hepatic damage. Dual hydrophobization achieved by formulating NPs with palmitic acid-modified siRNA (siPA-NPs) both reduced the amount of carrier polymer required to achieve optimal pharmacokinetic profiles and abrogated liver toxicities. We also show that optimized zwitterionic siPA-NPs are well-tolerated upon long-term, repeated administration in mice and exhibit greater than two-fold increased uptake in orthotopic MDA-MB-231 xenografts compared to commercial transfection reagent, in vivo-jetPEI®. These data suggest that charge ratio optimization has important in vivo implications and that dual hydrophobization strategies can be used to maximize both NP circulation time and safety.
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Affiliation(s)
- Meredith A. Jackson
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Sean K. Bedingfield
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Fang Yu
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Mitchell E. Stokan
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Rachel E. Miles
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | | | | | - Rachel H. Bonami
- Department of Medicine, Division of Rheumatology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Shrusti S. Patel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Peggy L. Kendall
- Department of Medicine, Division of Allergy, Pulmonary, and Critical Care, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Todd D. Giorgio
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Craig L. Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA,Corresponding author. (C.L. Duvall)
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Klein L, Fürst AE, Del Chicca F, Theiss F, Jackson MA. Clinical, radiographic and histologic findings, therapy and outcome in 15 horses with suture periostitis: a case series. PFERDEHEILKUNDE 2019. [DOI: 10.21836/pem20190301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Donati B, Fürst AE, Hässig M, Jackson MA. Epidemiology of fractures: The role of kick injuries in equine fractures. Equine Vet J 2018; 50:580-586. [PMID: 29441693 DOI: 10.1111/evj.12819] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 12/23/2017] [Accepted: 01/26/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND Fractures occur commonly in equids and often are associated with complications and a poor outcome. There are no reports on the epidemiology of fractures in a heterogeneous equine population. OBJECTIVES To study the epidemiology of fractures in a heterogeneous equine population, focusing on differences between fractures resulting from a kick and fractures, resulting from other causes and investigating predictors for recovery. STUDY DESIGN Retrospective case series. METHODS Data of all equids presented to the Equine Department, Vetsuisse Faculty, University of Zurich between 1990 and 2014 and diagnosed with a fracture were reviewed and those with a known cause were included in this study. Mann-Whitney and chi-squared tests were used to compare recovery rates of fractures resulting from a kick and fractures resulting from other causes, and a logistic regression was carried out for multivariate analysis of the most important factors affecting recovery. RESULTS Here, 1144 cases fulfilled the inclusion criteria. Of all fractures (with a known cause), 43.6% were the result of a kick from another equid. Kicks often produced open fractures (44.7%) that involved bones of the limbs (85.6%). Overall recovery was 70.1%. Logistic regression showed that high-grade lameness accompanying the fracture and severe comminution negatively affected recovery. MAIN LIMITATIONS The equids in this study were drawn from a referred population, which likely precluded the inclusion of both minor fractures and catastrophic fractures that necessitated immediate euthanasia. Moreover, many cases were excluded because the cause of the fracture could not be determined from the patient record. CONCLUSIONS Kicks are the most common cause of fractures in a heterogeneous equine population and measures to reduce the incidence of kicks are necessary in group-housing systems.
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Affiliation(s)
- B Donati
- Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - A E Fürst
- Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - M Hässig
- Section of Herd Health, Department of Farm Animals, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - M A Jackson
- Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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Werfel TA, Wang S, Jackson MA, Kavanaugh TE, Joly MM, Lee LH, Hicks DJ, Sanchez V, Ericsson PG, Kilchrist KV, Dimobi SC, Sarett SM, Brantley-Sieders DM, Cook RS, Duvall CL. Selective mTORC2 Inhibitor Therapeutically Blocks Breast Cancer Cell Growth and Survival. Cancer Res 2018; 78:1845-1858. [PMID: 29358172 DOI: 10.1158/0008-5472.can-17-2388] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/11/2017] [Accepted: 01/17/2018] [Indexed: 12/12/2022]
Abstract
Small-molecule inhibitors of the mTORC2 kinase (torkinibs) have shown efficacy in early clinical trials. However, the torkinibs under study also inhibit the other mTOR-containing complex mTORC1. While mTORC1/mTORC2 combined inhibition may be beneficial in cancer cells, recent reports describe compensatory cell survival upon mTORC1 inhibition due to loss of negative feedback on PI3K, increased autophagy, and increased macropinocytosis. Genetic models suggest that selective mTORC2 inhibition would be effective in breast cancers, but the lack of selective small-molecule inhibitors of mTORC2 have precluded testing of this hypothesis to date. Here we report the engineering of a nanoparticle-based RNAi therapeutic that can effectively silence the mTORC2 obligate cofactor Rictor. Nanoparticle-based Rictor ablation in HER2-amplified breast tumors was achieved following intratumoral and intravenous delivery, decreasing Akt phosphorylation and increasing tumor cell killing. Selective mTORC2 inhibition in vivo, combined with the HER2 inhibitor lapatinib, decreased the growth of HER2-amplified breast cancers to a greater extent than either agent alone, suggesting that mTORC2 promotes lapatinib resistance, but is overcome by mTORC2 inhibition. Importantly, selective mTORC2 inhibition was effective in a triple-negative breast cancer (TNBC) model, decreasing Akt phosphorylation and tumor growth, consistent with our findings that RICTOR mRNA correlates with worse outcome in patients with basal-like TNBC. Together, our results offer preclinical validation of a novel RNAi delivery platform for therapeutic gene ablation in breast cancer, and they show that mTORC2-selective targeting is feasible and efficacious in this disease setting.Significance: This study describes a nanomedicine to effectively inhibit the growth regulatory kinase mTORC2 in a preclinical model of breast cancer, targeting an important pathogenic enzyme in that setting that has been undruggable to date. Cancer Res; 78(7); 1845-58. ©2018 AACR.
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Affiliation(s)
- Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Shan Wang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Meghan Morrison Joly
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Linus H Lee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Donna J Hicks
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Violeta Sanchez
- Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Paula Gonzalez Ericsson
- Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Kameron V Kilchrist
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Somtochukwu C Dimobi
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Samantha M Sarett
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Dana M Brantley-Sieders
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.,Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Rebecca S Cook
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee. .,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.
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10
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Jackson MA, Werfel TA, Curvino EJ, Yu F, Kavanaugh TE, Sarett SM, Dockery MD, Kilchrist KV, Jackson AN, Giorgio TD, Duvall CL. Zwitterionic Nanocarrier Surface Chemistry Improves siRNA Tumor Delivery and Silencing Activity Relative to Polyethylene Glycol. ACS Nano 2017; 11:5680-5696. [PMID: 28548843 PMCID: PMC5919184 DOI: 10.1021/acsnano.7b01110] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Although siRNA-based nanomedicines hold promise for cancer treatment, conventional siRNA-polymer complex (polyplex) nanocarrier systems have poor pharmacokinetics following intravenous delivery, hindering tumor accumulation. Here, we determined the impact of surface chemistry on the in vivo pharmacokinetics and tumor delivery of siRNA polyplexes. A library of diblock polymers was synthesized, all containing the same pH-responsive, endosomolytic polyplex core-forming block but different corona blocks: 5 kDa (benchmark) and 20 kDa linear polyethylene glycol (PEG), 10 kDa and 20 kDa brush-like poly(oligo ethylene glycol), and 10 kDa and 20 kDa zwitterionic phosphorylcholine-based polymers (PMPC). In vitro, it was found that 20 kDa PEG and 20 kDa PMPC had the highest stability in the presence of salt or heparin and were the most effective at blocking protein adsorption. Following intravenous delivery, 20 kDa PEG and PMPC coronas both extended circulation half-lives 5-fold compared to 5 kDa PEG. However, in mouse orthotopic xenograft tumors, zwitterionic PMPC-based polyplexes showed highest in vivo luciferase silencing (>75% knockdown for 10 days with single IV 1 mg/kg dose) and 3-fold higher average tumor cell uptake than 5 kDa PEG polyplexes (20 kDa PEG polyplexes were only 2-fold higher than 5 kDa PEG). These results show that high molecular weight zwitterionic polyplex coronas significantly enhance siRNA polyplex pharmacokinetics without sacrificing polyplex uptake and bioactivity within tumors when compared to traditional PEG architectures.
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Affiliation(s)
- Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Elizabeth J Curvino
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Fang Yu
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Samantha M Sarett
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Mary D Dockery
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Kameron V Kilchrist
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Ayisha N Jackson
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Todd D Giorgio
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
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Werfel TA, Jackson MA, Kavanaugh TE, Kirkbride KC, Miteva M, Giorgio TD, Duvall C. Combinatorial optimization of PEG architecture and hydrophobic content improves ternary siRNA polyplex stability, pharmacokinetics, and potency in vivo. J Control Release 2017; 255:12-26. [PMID: 28366646 DOI: 10.1016/j.jconrel.2017.03.389] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 03/06/2017] [Accepted: 03/23/2017] [Indexed: 12/21/2022]
Abstract
A rationally-designed library of ternary siRNA polyplexes was developed and screened for gene silencing efficacy in vitro and in vivo with the goal of overcoming both cell-level and systemic delivery barriers. [2-(dimethylamino)ethyl methacrylate] (DMAEMA) was homopolymerized or copolymerized (50mol% each) with butyl methacrylate (BMA) from a reversible addition - fragmentation chain transfer (RAFT) chain transfer agent, with and without pre-conjugation to polyethylene glycol (PEG). Both single block polymers were tested as core-forming units, and both PEGylated, diblock polymers were screened as corona-forming units. Ternary siRNA polyplexes were assembled with varied amounts and ratios of core-forming polymers to PEGylated corona-forming polymers. The impact of polymer composition/ratio, hydrophobe (BMA) placement, and surface PEGylation density was correlated to important outcomes such as polyplex size, stability, pH-dependent membrane disruptive activity, biocompatibility, and gene silencing efficiency. The lead formulation, DB4-PDB12, was optimally PEGylated not only to ensure colloidal stability (no change in size by DLS between 0 and 24h) and neutral surface charge (0.139mV) but also to maintain higher cell uptake (>90% positive cells) than the most densely PEGylated particles. The DB4-PDB12 polyplexes also incorporated BMA in both the polyplex core- and corona-forming polymers, resulting in robust endosomolysis and in vitro siRNA silencing (~85% protein level knockdown) of the model gene luciferase across multiple cell types. Further, the DB4-PDB12 polyplexes exhibited greater stability, increased blood circulation time, reduced renal clearance, increased tumor biodistribution, and greater silencing of luciferase compared to our previously-optimized, binary parent formulation following intravenous (i.v.) delivery. This polyplex library approach enabled concomitant optimization of the composition and ratio of core- and corona-forming polymers (indirectly tuning PEGylation density) and identification of a ternary nanomedicine optimized to overcome important siRNA delivery barriers in vitro and in vivo.
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Affiliation(s)
- Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Kellye C Kirkbride
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Martina Miteva
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Todd D Giorgio
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Craig Duvall
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA.
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12
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Pallister T, Jackson MA, Martin TC, Glastonbury CA, Jennings A, Beaumont M, Mohney RP, Small KS, MacGregor A, Steves CJ, Cassidy A, Spector TD, Menni C, Valdes AM. Untangling the relationship between diet and visceral fat mass through blood metabolomics and gut microbiome profiling. Int J Obes (Lond) 2017; 41:1106-1113. [PMID: 28293020 PMCID: PMC5504448 DOI: 10.1038/ijo.2017.70] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 02/16/2017] [Accepted: 02/26/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND/OBJECTIVES Higher visceral fat mass (VFM) is associated with an increased risk for developing cardio-metabolic diseases. The mechanisms by which an unhealthy diet pattern may influence visceral fat (VF) development has yet to be examined through cutting-edge multi-omic methods. Therefore, our objective was to examine the dietary influences on VFM and identify gut microbiome and metabolite profiles that link food intakes to VFM. SUBJECTS/METHODS In 2218 twins with VFM, food intake and metabolomics data available we identified food intakes most strongly associated with VFM in 50% of the sample, then constructed and tested the 'VFM diet score' in the remainder of the sample. Using linear regression (adjusted for covariates, including body mass index and total fat mass), we investigated associations between the VFM diet score, the blood metabolomics profile and the fecal microbiome (n=889), and confirmed these associations with VFM. We replicated top findings in monozygotic (MZ) twins discordant (⩾1 s.d. apart) for VFM, matched for age, sex and the baseline genetic sequence. RESULTS Four metabolites were associated with the VFM diet score and VFM: hippurate, alpha-hydroxyisovalerate, bilirubin (Z,Z) and butyrylcarnitine. We replicated associations between VFM and the diet score (beta (s.e.): 0.281 (0.091); P=0.002), butyrylcarnitine (0.199 (0.087); P=0.023) and hippurate (-0.297 (0.095); P=0.002) in VFM-discordant MZ twins. We identified a single species, Eubacterium dolichum to be associated with the VFM diet score (0.042 (0.011), P=8.47 × 10-5), VFM (0.057 (0.019), P=2.73 × 10-3) and hippurate (-0.075 (0.032), P=0.021). Moreover, higher blood hippurate was associated with elevated adipose tissue expression neuroglobin, with roles in cellular oxygen homeostasis (0.016 (0.004), P=9.82x10-6). CONCLUSIONS We linked a dietary VFM score and VFM to E. dolichum and four metabolites in the blood. In particular, the relationship between hippurate, a metabolite derived from microbial metabolism of dietary polyphenols, and reduced VFM, the microbiome and increased adipose tissue expression of neuroglobin provides potential mechanistic insight into the influence of diet on VFM.
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Affiliation(s)
- T Pallister
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - M A Jackson
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - T C Martin
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - C A Glastonbury
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - A Jennings
- Department of Nutrition, Norwich Medical School, University of East Anglia, Norwich, UK
| | - M Beaumont
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | | | - K S Small
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - A MacGregor
- Department of Nutrition, Norwich Medical School, University of East Anglia, Norwich, UK
| | - C J Steves
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - A Cassidy
- Department of Nutrition, Norwich Medical School, University of East Anglia, Norwich, UK
| | - T D Spector
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - C Menni
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK
| | - A M Valdes
- Department of Twin Research and Genetic Epidemiology, Kings College London, London, UK.,Academic Rheumatology Clinical Sciences Building, University of Nottingham, Nottingham City Hospital, Nottingham, UK
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13
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Menni C, Jackson MA, Pallister T, Steves CJ, Spector TD, Valdes AM. Gut microbiome diversity and high-fibre intake are related to lower long-term weight gain. Int J Obes (Lond) 2017; 41:1099-1105. [PMID: 28286339 PMCID: PMC5500185 DOI: 10.1038/ijo.2017.66] [Citation(s) in RCA: 212] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/15/2017] [Accepted: 03/05/2017] [Indexed: 12/16/2022]
Abstract
Background: Cross-sectional studies suggest that the microbes in the human gut have a role in obesity by influencing the human body’s ability to extract and store calories. The aim of this study was to assess if there is a correlation between change in body weight over time and gut microbiome composition. Methods: We analysed 16S ribosomal RNA gene sequence data derived from the faecal samples of 1632 healthy females from TwinsUK to investigate the association between gut microbiome measured cross-sectionally and longitudinal weight gain (adjusted for caloric intake and baseline body mass index). Dietary fibre intake was investigated as a possible modifier. Results: Less than half of the variation in long-term weight change was found to be heritable (h2=0.41 (0.31, 0.47)). Gut microbiota diversity was negatively associated with long-term weight gain, whereas it was positively correlated with fibre intake. Nine bacterial operational taxonomic units (OTUs) were significantly associated with weight gain after adjusting for covariates, family relatedness and multiple testing (false discovery rate <0.05). OTUs associated with lower long-term weight gain included those assigned to Ruminococcaceae (associated in mice with improved energy metabolism) and Lachnospiraceae. A Bacterioides species OTU was associated with increased risk of weight gain but this appears to be driven by its correlation with lower levels of diversity. Conclusions: High gut microbiome diversity, high-fibre intake and OTUs implicated in animal models of improved energy metabolism are all correlated with lower term weight gain in humans independently of calorie intake and other confounders.
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Affiliation(s)
- C Menni
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - M A Jackson
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - T Pallister
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - C J Steves
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - T D Spector
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - A M Valdes
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK.,Academic Rheumatology, University of Nottingham, Nottingham, UK
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Jackson MA, Fürst AE, Koch S, von Rechenberg B, Richards PJ. Effect of recombinant human bone morphogenetic protein 2 (rhBMP-2) on equine bone formation: A preliminary in vitro and in vivo evaluation. PFERDEHEILKUNDE 2017. [DOI: 10.21836/pem20170501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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Schön S, Fürst AE, Ohlerth S, Kircher PR, Roos M, Jackson MA. Computed tomographic versus radiographic assessment of the visibility and features of subchondral cystic lesions in equine limbs. PFERDEHEILKUNDE 2017. [DOI: 10.21836/pem20170306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Chen AL, Jackson MA, Lin AY, Figueroa ER, Hu YS, Evans ER, Asthana V, Young JK, Drezek RA. Changes in Optical Properties of Plasmonic Nanoparticles in Cellular Environments are Modulated by Nanoparticle PEGylation and Serum Conditions. Nanoscale Res Lett 2016; 11:303. [PMID: 27316744 PMCID: PMC4912538 DOI: 10.1186/s11671-016-1524-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/09/2016] [Indexed: 05/14/2023]
Abstract
When plasmonic nanoparticles (NPs) are internalized by cells and agglomerate within intracellular vesicles, their optical spectra can shift and broaden as a result of plasmonic coupling of NPs in close proximity to one another. For such optical changes to be accounted for in the design of plasmonic NPs for light-based biomedical applications, quantitative design relationships between designable factors and spectral shifts need to be established. Here we begin building such a framework by investigating how functionalization of gold NPs (AuNPs) with biocompatible poly(ethylene) glycol (PEG), and the serum conditions in which the NPs are introduced to cells impact the optical changes exhibited by NPs in a cellular context. Utilizing darkfield hyperspectral imaging, we find that PEGylation decreases the spectral shifting and spectral broadening experienced by 100 nm AuNPs following uptake by Sk-Br-3 cells, but up to a 33 ± 12 nm shift in the spectral peak wavelength can still occur. The serum protein-containing biological medium also modulates the spectral changes experienced by cell-exposed NPs through the formation of a protein corona on the surface of NPs that mediates NP interactions with cells: PEGylated AuNPs exposed to cells in serum-free conditions experience greater spectral shifts than in serum-containing environments. Moreover, increased concentrations of serum (10, 25, or 50 %) result in the formation of smaller intracellular NP clusters and correspondingly reduced spectral shifts after 5 and 10 h NP-cell exposure. However, after 24 h, NP cluster size and spectral shifts are comparable and become independent of serum concentration. By elucidating the impact of PEGylation and serum concentration on the spectral changes experienced by plasmonic NPs in cells, this study provides a foundation for the optical engineering of plasmonic NPs for use in biomedical environments.
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Affiliation(s)
- Allen L. Chen
- />Department of Bioengineering, Rice University, Houston, 77005 TX USA
| | | | - Adam Y. Lin
- />Department of Bioengineering, Rice University, Houston, 77005 TX USA
| | | | - Ying S. Hu
- />Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, 92037 CA USA
| | - Emily R. Evans
- />Department of Bioengineering, Rice University, Houston, 77005 TX USA
| | | | - Joseph K. Young
- />Department of Electrical and Computer Engineering, Rice University, Houston, 77005 TX USA
| | - Rebekah A. Drezek
- />Department of Bioengineering, Rice University, Houston, 77005 TX USA
- />Department of Electrical and Computer Engineering, Rice University, Houston, 77005 TX USA
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17
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Sarett SM, Werfel TA, Chandra I, Jackson MA, Kavanaugh TE, Hattaway ME, Giorgio TD, Duvall CL. Hydrophobic interactions between polymeric carrier and palmitic acid-conjugated siRNA improve PEGylated polyplex stability and enhance in vivo pharmacokinetics and tumor gene silencing. Biomaterials 2016; 97:122-32. [PMID: 27163624 DOI: 10.1016/j.biomaterials.2016.04.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 12/11/2022]
Abstract
Formation of stable, long-circulating siRNA polyplexes is a significant challenge in translation of intravenously-delivered, polymeric RNAi cancer therapies. Here, we report that siRNA hydrophobization through conjugation to palmitic acid (siPA) improves stability, in vivo pharmacokinetics, and tumor gene silencing of PEGylated nanopolyplexes (siPA-NPs) with balanced cationic and hydrophobic content in the core relative to the analogous polyplexes formed with unmodified siRNA, si-NPs. Hydrophobized siPA loaded into the NPs at a lower charge ratio (N(+):P(-)) relative to unmodified siRNA, and siPA-NPs had superior resistance to siRNA cargo unpackaging in comparison to si-NPs upon exposure to the competing polyanion heparin and serum. In vitro, siPA-NPs increased uptake in MDA-MB-231 breast cancer cells (100% positive cells vs. 60% positive cells) but exhibited equivalent silencing of the model gene luciferase relative to si-NPs. In vivo in a murine model, the circulation half-life of intravenously-injected siPA-NPs was double that of si-NPs, resulting in a >2-fold increase in siRNA biodistribution to orthotopic MDA-MB-231 mammary tumors. The increased circulation half-life of siPA-NPs was dependent upon the hydrophobic interactions of the siRNA and the NP core component and not just siRNA hydrophobization, as siPA did not contribute to improved circulation time relative to unmodified siRNA when delivered using polyplexes with a fully cationic core. Intravenous delivery of siPA-NPs also achieved significant silencing of the model gene luciferase in vivo (∼40% at 24 h after one treatment and ∼60% at 48 h after two treatments) in the murine MDA-MB-231 tumor model, while si-NPs only produced a significant silencing effect after two treatments. These data suggest that stabilization of PEGylated siRNA polyplexes through a combination of hydrophobic and electrostatic interactions between siRNA cargo and the polymeric carrier improves in vivo pharmacokinetics and tumor gene silencing relative to conventional formulations that are stabilized solely by electrostatic interactions.
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Affiliation(s)
- Samantha M Sarett
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Irene Chandra
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Madison E Hattaway
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Todd D Giorgio
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA.
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18
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Venkatakrishnan SV, Drummy LF, Jackson MA, Bouman CA, Simmons JP, De Graef M. A phantom-based forward projection approach in support of model-based iterative reconstructions for HAADF-STEM tomography. Ultramicroscopy 2015; 160:7-17. [PMID: 26409683 DOI: 10.1016/j.ultramic.2015.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/25/2015] [Accepted: 09/16/2015] [Indexed: 11/16/2022]
Abstract
We introduce a forward model for the computation of high angle annular dark field (HAADF) images of nano-crystalline spherical particles and apply it to image simulations for assemblies of nano-spheres of Al, Cu, and Au with a range of sizes, as well as an artificial bi-sphere, consisting of solid hemispheres of Al and Cu or Al and Au. Comparison of computed intensity profiles with experimental observations on Al spheres at different microscope accelerating voltages provides confidence in the forward model. Simulated tomographic tilt series for both HAADF and bright field (BF) images are then used to illustrate that the model-based iterative reconstruction (MBIR) approach is capable of reconstructing sphere configurations of mixed atomic number, with the correct relative reconstructed intensity ratio proportional to the square of the atomic number ratio.
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Affiliation(s)
| | - L F Drummy
- Air Force Research Laboratory, Wright Patterson AFB, OH 45433, USA.
| | - M A Jackson
- BlueQuartz Software, Springboro, OH 45066, USA.
| | - C A Bouman
- Purdue University, West Lafayette, IN 47907, USA.
| | - J P Simmons
- Air Force Research Laboratory, Wright Patterson AFB, OH 45433, USA.
| | - M De Graef
- Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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19
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Chen AL, Hu YS, Jackson MA, Lin AY, Young JK, Langsner RJ, Drezek RA. Quantifying spectral changes experienced by plasmonic nanoparticles in a cellular environment to inform biomedical nanoparticle design. Nanoscale Res Lett 2014; 9:454. [PMID: 25258596 PMCID: PMC4164329 DOI: 10.1186/1556-276x-9-454] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/23/2014] [Indexed: 05/14/2023]
Abstract
Metal nanoparticles (NPs) scatter and absorb light in precise, designable ways, making them agile candidates for a variety of biomedical applications. When NPs are introduced to a physiological environment and interact with cells, their physicochemical properties can change as proteins adsorb on their surface and they agglomerate within intracellular endosomal vesicles. Since the plasmonic properties of metal NPs are dependent on their geometry and local environment, these physicochemical changes may alter the NPs' plasmonic properties, on which applications such as plasmonic photothermal therapy and photonic gene circuits are based. Here we systematically study and quantify how metal NPs' optical spectra change upon introduction to a cellular environment in which NPs agglomerate within endosomal vesicles. Using darkfield hyperspectral imaging, we measure changes in the peak wavelength, broadening, and distribution of 100-nm spherical gold NPs' optical spectra following introduction to human breast adenocarcinoma Sk-Br-3 cells as a function of NP exposure dose and time. On a cellular level, spectra shift up to 78.6 ± 23.5 nm after 24 h of NP exposure. Importantly, spectra broaden with time, achieving a spectral width of 105.9 ± 11.7 nm at 95% of the spectrum's maximum intensity after 24 h. On an individual intracellular NP cluster (NPC) level, spectra also show significant shifting, broadening, and heterogeneity after 24 h. Cellular transmission electron microscopy (TEM) and electromagnetic simulations of NPCs support the trends in spectral changes we measured. These quantitative data can help guide the design of metal NPs introduced to cellular environments in plasmonic NP-mediated biomedical technologies.
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Affiliation(s)
- Allen L Chen
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Ying S Hu
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | | | - Adam Y Lin
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Joseph K Young
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
| | - Robert J Langsner
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Rebekah A Drezek
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
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20
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Jackson MA, Vizard AL, Anderson GA, Mattoon JS, Lavelle RB, Smithenson BT, Lester NV, Clarke AF, Whitton RC. An assessment of intra- and interobserver agreement of reporting orthopaedic findings on presale radiographs of Thoroughbred yearlings. Equine Vet J 2013; 46:567-74. [PMID: 23889034 DOI: 10.1111/evj.12150] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 07/16/2013] [Indexed: 11/26/2022]
Abstract
REASONS FOR PERFORMING STUDY Radiography is commonly used in clinical practice but agreement of reporting of radiographically detected orthopaedic findings in horses has rarely been studied. OBJECTIVES To assess agreement within and between observers for reporting of orthopaedic findings on presale radiographs of Thoroughbred yearlings. STUDY DESIGN Retrospective analysis of archived radiographs. METHODS Four veterinary radiology specialists each twice examined 167 sets of radiographs for orthopaedic findings in the fore feet, fore and hind fetlocks, carpi, tarsi and stifles. There were 27 findings analysed for agreement. Kappa statistic (κ), percentage of positive agreement (Ppos) and percentage of negative agreement are reported. RESULTS An excellent percentage of negative agreement was observed for all findings, with the exception of regular vascular channels of the proximal sesamoid bones. Ppos and κ results were variable. The presence of extra carpal bones, osseous cyst-like lesions of the ulnar carpal bone, sagittal ridge defects of the third metacarpus, fracture of the fore and hind proximal sesamoid bones, regular vascular channels in the hind proximal sesamoids, osteochondrosis lesions of the distal intermediate ridge and/or medial malleoli of the tibia, and osseous cyst-like lesions in the medial femoral condyle was consistently observed with an intra- and interagreement κ≥0.5 and Ppos≥50%. Lucency within the proximal sesamoids consistently had an observed intra- and interagreement κ<0.4 and Ppos<40%. CONCLUSIONS Observation of orthopaedic findings on yearling repository radiographs showed generally excellent agreement on the absence of findings, but variable agreement on the presence of findings. Agreement was good for larger and easy to categorise radiographic findings. More accurate definitions and training need to be developed to improve agreement within and between observers for orthopaedic findings with poor or fair to good agreement.
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Affiliation(s)
- M A Jackson
- Faculty of Veterinary Science, The University of Melbourne, Victoria, Australia
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21
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Jackson MA, Ohlerth S, Kummer M, Bettschart R, Watson J, Manera CL, von Rechenberg B, Auer J, Fürst A. Use of a parathyroid hormone peptide (PTH1-34)-enriched fibrin hydrogel for the treatment of subchondral cystic lesions in 15 horses. PFERDEHEILKUNDE 2012. [DOI: 10.21836/pem20120601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Litton JK, Etzel CJ, Jackson MA, Muse KI, Turco D, Schover LR, Theriault RL, Mattair D, Lu KH, Hortobagyi GN, Arun BK. P2-13-05: Breast Cancer, BRCA Mutations and Attitudes Regarding Pregnancy and Preimplantation Genetic Diagnosis. Cancer Res 2011. [DOI: 10.1158/0008-5472.sabcs11-p2-13-05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Breast cancer is associated with treatment-related infertility and has been demonstrated to be a major concern for premenopausal survivors. Detection of a BRCA deleterious mutation may also affect attitudes regarding future childbearing. Preimplantation genetic diagnosis (PGD) allows women to use in vitro fertilization (IVF) to implant only those embryos without a BRCA mutation. The ability to test the fetus for BRCA mutations is also available through amniocentesis and chorionic villus sampling (CVS). The objective of this study was to evaluate attitudes about childbearing and fertility in women being evaluated for a BRCA mutation. Methods: Women with childbearing potential who were referred to the Clinical Cancer Genetics Clinic to be evaluated for a BRCA mutation were invited to participate in this survey. The questionnaire was administered prior to genetic counseling. A follow-up was administered after the BRCA results were disclosed. The survey queried participants regarding their attitudes on fertility, pregnancy as it may relate to cancer and the potential of a BRCA mutation. Other questions detailed attitudes regarding IVF, PGD, and CVS in these instances. Descriptive statistics were used. Results: One hundred and twenty-eight women completed pre-questionnaires and to date 76 have completed post results disclosure questionnaires. The mean age was 33 (range 21–44) with 69.5% with a diagnosis of breast cancer, 39.8% received chemotherapy and 60.9% already had at least 1 biological child. A future child was desired by 45.3% although 53.1% worried that their children would have an increased risk of cancer. Regarding PGD, although only 30.9% (38/123) said that they would use PGD, 80.2% felt that the testing should be available to families with inherited cancers. Regarding fetal testing via amniocentesis or CVS, 29.7% would have the fetus tested and 7% would consider termination if a genetic mutation was identified. Additionally, 69.5% felt it was important to receive fertility counseling and treatment at the same place where they receive their cancer care. To date 8 women have been diagnosed with a BRCA1 mutation and 4 with a BRCA2 mutation. When asked similar questions after their genetic results were disclosed, 2 women who had previously stated they would not use PGD changed their mind. Conclusions: Future pregnancies are important to many breast cancer survivors. BRCA mutation carriers have the option to have children without passing on their genetic risk for cancer. Although few would use these interventions, a large majority felt it was important to have information about these choices and to have options for fertility preservation options addressed at the center where cancer care is delivered.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-13-05.
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Affiliation(s)
- JK Litton
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - CJ Etzel
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - MA Jackson
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - KI Muse
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - D Turco
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - LR Schover
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - RL Theriault
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - D Mattair
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - KH Lu
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - GN Hortobagyi
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
| | - BK Arun
- 1The University of Texas MD Anderson Cancer Center, Houston, TX
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Glenzer SH, MacGowan BJ, Meezan NB, Adams PA, Alfonso JB, Alger ET, Alherz Z, Alvarez LF, Alvarez SS, Amick PV, Andersson KS, Andrews SD, Antonini GJ, Arnold PA, Atkinson DP, Auyang L, Azevedo SG, Balaoing BNM, Baltz JA, Barbosa F, Bardsley GW, Barker DA, Barnes AI, Baron A, Beeler RG, Beeman BV, Belk LR, Bell JC, Bell PM, Berger RL, Bergonia MA, Bernardez LJ, Berzins LV, Bettenhausen RC, Bezerides L, Bhandarkar SD, Bishop CL, Bond EJ, Bopp DR, Borgman JA, Bower JR, Bowers GA, Bowers MW, Boyle DT, Bradley DK, Bragg JL, Braucht J, Brinkerhoff DL, Browning DF, Brunton GK, Burkhart SC, Burns SR, Burns KE, Burr B, Burrows LM, Butlin RK, Cahayag NJ, Callahan DA, Cardinale PS, Carey RW, Carlson JW, Casey AD, Castro C, Celeste JR, Chakicherla AY, Chambers FW, Chan C, Chandrasekaran H, Chang C, Chapman RF, Charron K, Chen Y, Christensen MJ, Churby AJ, Clancy TJ, Cline BD, Clowdus LC, Cocherell DG, Coffield FE, Cohen SJ, Costa RL, Cox JR, Curnow GM, Dailey MJ, Danforth PM, Darbee R, Datte PS, Davis JA, Deis GA, Demaret RD, Dewald EL, Di Nicola P, Di Nicola JM, Divol L, Dixit S, Dobson DB, Doppner T, Driscoll JD, Dugorepec J, Duncan JJ, Dupuy PC, Dzenitis EG, Eckart MJ, Edson SL, Edwards GJ, Edwards MJ, Edwards OD, Edwards PW, Ellefson JC, Ellerbee CH, Erbert GV, Estes CM, Fabyan WJ, Fallejo RN, Fedorov M, Felker B, Fink JT, Finney MD, Finnie LF, Fischer MJ, Fisher JM, Fishler BT, Florio JW, Forsman A, Foxworthy CB, Franks RM, Frazier T, Frieder G, Fung T, Gawinski GN, Gibson CR, Giraldez E, Glenn SM, Golick BP, Gonzales H, Gonzales SA, Gonzalez MJ, Griffin KL, Grippen J, Gross SM, Gschweng PH, Gururangan G, Gu K, Haan SW, Hahn SR, Haid BJ, Hamblen JE, Hammel BA, Hamza AV, Hardy DL, Hart DR, Hartley RG, Haynam CA, Heestand GM, Hermann MR, Hermes GL, Hey DS, Hibbard RL, Hicks DG, Hinkel DE, Hipple DL, Hitchcock JD, Hodtwalker DL, Holder JP, Hollis JD, Holtmeier GM, Huber SR, Huey AW, Hulsey DN, Hunter SL, Huppler TR, Hutton MS, Izumi N, Jackson JL, Jackson MA, Jancaitis KS, Jedlovec DR, Johnson B, Johnson MC, Johnson T, Johnston MP, Jones OS, Kalantar DH, Kamperschroer JH, Kauffman RL, Keating GA, Kegelmeyer LM, Kenitzer SL, Kimbrough JR, King K, Kirkwood RK, Klingmann JL, Knittel KM, Kohut TR, Koka KG, Kramer SW, Krammen JE, Krauter KG, Krauter GW, Krieger EK, Kroll JJ, La Fortune KN, Lagin LJ, Lakamsani VK, Landen OL, Lane SW, Langdon AB, Langer SH, Lao N, Larson DW, Latray D, Lau GT, Le Pape S, Lechleiter BL, Lee Y, Lee TL, Li J, Liebman JA, Lindl JD, Locke SF, Loey HK, London RA, Lopez FJ, Lord DM, Lowe-Webb RR, Lown JG, Ludwigsen AP, Lum NW, Lyons RR, Ma T, MacKinnon AJ, Magat MD, Maloy DT, Malsbury TN, Markham G, Marquez RM, Marsh AA, Marshall CD, Marshall SR, Maslennikov IL, Mathisen DG, Mauger GJ, Mauvais MY, McBride JA, McCarville T, McCloud JB, McGrew A, McHale B, MacPhee AG, Meeker JF, Merill JS, Mertens EP, Michel PA, Miller MG, Mills T, Milovich JL, Miramontes R, Montesanti RC, Montoya MM, Moody J, Moody JD, Moreno KA, Morris J, Morriston KM, Nelson JR, Neto M, Neumann JD, Ng E, Ngo QM, Olejniczak BL, Olson RE, Orsi NL, Owens MW, Padilla EH, Pannell TM, Parham TG, Patterson RW, Pavel G, Prasad RR, Pendlton D, Penko FA, Pepmeier BL, Petersen DE, Phillips TW, Pigg D, Piston KW, Pletcher KD, Powell CL, Radousky HB, Raimondi BS, Ralph JE, Rampke RL, Reed RK, Reid WA, Rekow VV, Reynolds JL, Rhodes JJ, Richardson MJ, Rinnert RJ, Riordan BP, Rivenes AS, Rivera AT, Roberts CJ, Robinson JA, Robinson RB, Robison SR, Rodriguez OR, Rogers SP, Rosen MD, Ross GF, Runkel M, Runtal AS, Sacks RA, Sailors SF, Salmon JT, Salmonson JD, Saunders RL, Schaffer JR, Schindler TM, Schmitt MJ, Schneider MB, Segraves KS, Shaw MJ, Sheldrick ME, Shelton RT, Shiflett MK, Shiromizu SJ, Shor M, Silva LL, Silva SA, Skulina KM, Smauley DA, Smith BE, Smith LK, Solomon AL, Sommer S, Soto JG, Spafford NI, Speck DE, Springer PT, Stadermann M, Stanley F, Stone TG, Stout EA, Stratton PL, Strausser RJ, Suter LJ, Sweet W, Swisher MF, Tappero JD, Tassano JB, Taylor JS, Tekle EA, Thai C, Thomas CA, Thomas A, Throop AL, Tietbohl GL, Tillman JM, Town RPJ, Townsend SL, Tribbey KL, Trummer D, Truong J, Vaher J, Valadez M, Van Arsdall P, Van Prooyen AJ, Vergel de Dios EO, Vergino MD, Vernon SP, Vickers JL, Villanueva GT, Vitalich MA, Vonhof SA, Wade FE, Wallace RJ, Warren CT, Warrick AL, Watkins J, Weaver S, Wegner PJ, Weingart MA, Wen J, White KS, Whitman PK, Widmann K, Widmayer CC, Wilhelmsen K, Williams EA, Williams WH, Willis L, Wilson EF, Wilson BA, Witte MC, Work K, Yang PS, Young BK, Youngblood KP, Zacharias RA, Zaleski T, Zapata PG, Zhang H, Zielinski JS, Kline JL, Kyrala GA, Niemann C, Kilkenny JD, Nikroo A, Van Wonterghem BM, Atherton LJ, Moses EI. Demonstration of ignition radiation temperatures in indirect-drive inertial confinement fusion hohlraums. Phys Rev Lett 2011; 106:085004. [PMID: 21405580 DOI: 10.1103/physrevlett.106.085004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Indexed: 05/30/2023]
Abstract
We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.
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Affiliation(s)
- S H Glenzer
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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Jackson MA, Bothast RJ. Carbon Concentration and Carbon-to-Nitrogen Ratio Influence Submerged-Culture Conidiation by the Potential Bioherbicide Colletotrichum truncatum NRRL 13737. Appl Environ Microbiol 2010; 56:3435-8. [PMID: 16348348 PMCID: PMC184974 DOI: 10.1128/aem.56.11.3435-3438.1990] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We assessed the influence of various carbon concentrations and carbon-to-nitrogen (C:N) ratios on Colletotrichum truncatum NRRL 13737 conidium formation in submerged cultures grown in a basal salts medium containing various amounts of glucose and Casamino Acids. Under the nutritional conditions tested, the highest conidium concentrations were produced in media with carbon concentrations of 4.0 to 15.3 g/liter. High carbon concentrations (20.4 to 40.8 g/liter) inhibited sporulation and enhanced the formation of microsclerotiumlike hyphal masses. At all the carbon concentrations tested, a culture grown in a medium with a C:N ratio of 15:1 produced more conidia than cultures grown in media with C:N ratios of 40:1 or 5:1. While glucose exhaustion was often coincident with conidium formation, cultures containing residual glucose sporulated and those with high carbon concentrations (>25 g/liter) exhausted glucose without sporulation. Nitrogen source studies showed that the levels of C. truncatum NRRL 13737 conidiation were similar for all protein hydrolysates tested. Reduced conidiation occurred when amino acid and inorganic nitrogen sources were used. Of the nine carbon sources evaluated, acetate as the sole carbon source resulted in the lowest level of sporulation.
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Affiliation(s)
- M A Jackson
- Fermentation Biochemistry Research, Northern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, Illinois 61604
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Jackson MA, Schisler DA. The Composition and Attributes of Colletotrichum truncatum Spores Are Altered by the Nutritional Environment. Appl Environ Microbiol 2010; 58:2260-5. [PMID: 16348737 PMCID: PMC195765 DOI: 10.1128/aem.58.7.2260-2265.1992] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous sporulation studies with Colletotrichum truncatum NRRL 13737, a fungal pathogen of the noxious weed Sesbania exaltata, showed that the carbon-to-nitrogen (CN) ratio of the conidiation medium influenced spore yield, morphology, and efficacy in inciting disease in S. exaltata. Spores produced in a medium with a CN ratio of 10:1 were more effective than were spores produced in a 30:1 or 80:1 ratio in causing disease in S. exaltata. With a basal salts medium supplemented with glucose and Casamino Acids, substrate utilization, spore production, biomass accumulation, and biomass and spore composition were compared in submerged cultures of C. truncatum grown in media with CN ratios of 80:1, 30:1, and 10:1. All cultures were sporulating by day 2, and spore concentrations in 5-day-old cultures were significantly different: 30:1 > 10:1 > 80:1. Amino acid and glucose utilization was balanced in cultures grown in media with a CN ratio of 10:1, whereas cultures grown in media with a CN ratio of 30:1 or 80:1 depleted amino acids prior to glucose. Conidia produced in media with a CN ratio of 10:1 contained significantly more protein (32% of dry weight) and less lipid (17% of dry weight) than conidia produced in media with a CN ratio of either 30:1 (15% protein, 33% lipid) or 80:1 (12% protein, 37% lipid). The higher lipid content of spores produced in media with a CN ratio of 30:1 or 80:1 was associated with the presence of increased numbers of lipid droplets. Optimization studies on conidia produced in media with CN ratios between 30:1 and 10:1 which compared yield, attributes, and efficacy in inciting disease in S. exaltata suggest that media with a CN ratio of 15:1 to 20:1 may be optimal for conidium production.
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Affiliation(s)
- M A Jackson
- Fermentation Biochemistry Research, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, Illinois 61604
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Brown JA, Hinchcliff KW, Jackson MA, Dredge AF, O'Callaghan RA, McCaffrey JR, Slocombe RF, Clarke AF. Prevalence of pharyngeal and laryngeal abnormalities in Thoroughbreds racing in Australia, and their association with performance. Equine Vet J 2010; 37:397-401. [PMID: 16163940 DOI: 10.2746/042516405774480021] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Little information is available regarding the prevalence of abnormalities of the upper airway and their association with performance in the general population of Thoroughbred racehorses. OBJECTIVES To describe the prevalence of selected abnormalities of the upper airway and their association with performance in Thoroughbred racehorses in Australia. HYPOTHESIS That abnormalities of the upper airway of Thoroughbred racehorses are associated with poor race performance. METHODS Rhinolaryngoscopy was performed after racing and presence and characteristics of abnormalities of the larynx and pharynx were recorded in a prospective cross-sectional study of Thoroughbred horses racing in Victoria, Australia. RESULTS Rhinolaryngoscopy was performed once on each of 744 horses over 35 months. Fifty abnormalities of the upper airway were detected in 47 horses (6.3%, 95% confidence interval [CI] 4.7-83%). Epiglottic entrapment was detected in 7 horses (0.9%, 95% CI 0.4-1.9%) and was significantly (P = 0.015) associated with superior performance. Grade 2 asymmetry (4 grade scale) of the left arytenoid cartilage was detected in 9 horses (1.2%, 95% CI 0.5-2.4%) and was also associated with superior performance (P<0.001). Ulceration or erosion of the mucosa of the axial surface of one or both arytenoids was detected in 18 horses (2.4%, 95% CI 13-3.8%) and was not associated with alterations in exercise performance (P = 0.31). CONCLUSIONS Epiglottic entrapment, Grade 2 laryngeal asymmetry and mucosal erosions detected in Thoroughbred racehorses were not associated with impaired performance; therefore, surgical correction and concern over laryngeal function in horses with Grade 2 asymmetry may not be necessary in individuals performing to expectation.
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Affiliation(s)
- J A Brown
- School of Veterinary Science, University of Melbourne, Princes Highway, Werribee, Victoria 3030, Australia
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Lea IA, Jackson MA, Li X, Bailey S, Peddada SD, Dunnick JK. Genetic pathways and mutation profiles of human cancers: site- and exposure-specific patterns. Carcinogenesis 2007; 28:1851-8. [PMID: 17693665 PMCID: PMC2131731 DOI: 10.1093/carcin/bgm176] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cancer is a complex disease that involves the accumulation of both genetic and epigenetic alterations of numerous genes. Data in the Genetic Alterations in Cancer database for gene mutations and allelic loss [loss of heterozygosity (LOH)] in human tumors (e.g. lung, oral, esophagus, stomach and colon/rectum) were reviewed. Results for the genes and pathways implicated in tumor development at these sites are presented. Mutation incidence, spectra and codon specificity are described for lung, larynx and oral tumors. LOH occurred more frequently than gene mutations in tumors from all sites examined. The cell cycle gene, TP53 (all sites), and cell signaling gene, APC (colorectal and gastric cancers), were the only genes with similar incidences of LOH and mutation. Alterations of one or more cell cycle and cell signaling genes were reported for tumors from each site. Site-specific activation was apparent in the cell signaling mitogen-activated protein kinase oncogenes (KRAS in lung, HRAS in oral cancers and BRAF in esophageal and colorectal cancers). Analysis of genetic changes in lung tumors showed that the incidence of mutations in the TP53 and KRAS genes and the incidence of LOH in the FHIT gene were significantly greater in smokers versus non-smokers (P < 0.01). In lung and oral cancers, the TP53 GC --> TA transversion frequency increased with tobacco smoke exposure (P < 0.05). Furthermore, the TP53 mutational hot spots for lung and laryngeal cancers from smokers included codons 157, 245 and 273, whereas for oral tumors included codons 280 and 281.
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Affiliation(s)
- I A Lea
- Integrated Laboratory Systems, Inc., Research Triangle Park, NC 27709, USA.
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Vega FE, Jackson MA, McGuire MR. Germination of conidia and blastospores of Paecilomyces fumosoroseus on the cuticle of the silverleaf whitefly, Bemisia argentifolii. Mycopathologia 2006; 147:33-5. [PMID: 16308757 DOI: 10.1023/a:1007011801491] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- F E Vega
- USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, Illinois, 61604, USA
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Abstract
Exposure to violence in childhood is associated with aggression in adulthood. The high level of community violence in Jamaica is likely to expose Jamaican children to violence. There has been no detailed study of the exposure of Jamaican children to violence in their daily lives. Some 1674 urban 11-12-year-old children, previously part of a national birth cohort study, completed a questionnaire detailing their exposure to violence as witnesses, victims and aggressors. Their parents completed a socio-economic questionnaire. Jamaican children had high levels of exposure to physical violence. A quarter of the children had witnessed severe acts of physical violence such as robbery, shooting and gang wars, a fifth had been victims of serious threats or robbery and one in every twelve had been stabbed. Children reported being least exposed to sexual violence and to being shot at. Robbery was an almost universal experience affecting children from all schools and socio-economic groups. The single commonest experience as a victim of violence was the loss of a family member or close friend to murder, affecting 36.8% of children. Children's experiences of witnessing violence occurred chiefly in their communities but their personal experiences of violence occurred at school. Boys and children attending primary school had greater exposure to violence as witnesses and victims. Socio-economic status discriminated exposure to physical violence as witnesses but not as victims. Intervention strategies to reduce children's exposure to violence should include community education on the impact of exposure to violence on children, particularly the loss of a significant person, and the development of a range of school-based violence prevention programmes.
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Affiliation(s)
- M E Samms-Vaughan
- Department of Obstetrics, Gynaecology and Child Health, Section of Child Health, The University of the West Indies, Kingston 7, Jamaica, West Indies.
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Schisler DA, Slininger PJ, Behle RW, Jackson MA. Formulation of Bacillus spp. for Biological Control of Plant Diseases. Phytopathology 2004; 94:1267-71. [PMID: 18944465 DOI: 10.1094/phyto.2004.94.11.1267] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
ABSTRACT Maximizing the potential for successfully developing and deploying a biocontrol product begins with a carefully crafted microbial screening procedure, proceeds with developing mass production protocols that optimize product quantity and quality, and ends with devising a product formulation that preserves shelf-life, aids product delivery, and enhances bioactivity. Microbial selection procedures that require prospective bio-control agents to possess both efficacy and amenability to production in liquid culture increase the likelihood of selecting agents with enhanced commercial development potential. Scale-up of biomass production procedures must optimize product quantity without compromise of product efficacy or amenability to stabilization and formulation. Formulation of Bacillus spp. for use against plant pathogens is an enormous topic in general terms but limited in published specifics regarding formulations used in commercially available products. Types of formulations include dry products such as wettable powders, dusts, and granules, and liquid products including cell suspensions in water, oils, and emulsions. Cells can also be microencapsulated. Considerations critical to designing successful formulations of microbial biomass are many fold and include preserving biomass viability during stabilization, drying, and rehydration; aiding biomass delivery, target coverage, and target adhesion; and enhancing biomass survival and efficacy after delivery to the target. Solutions to these formulation considerations will not necessarily be compatible. Data from several biocontrol systems including the use of B. subtilis OH 131.1 (NRRL B-30212) to reduce Fusarium head blight of wheat are used to illustrate many of these issues. Using our recently described assay for efficiently evaluating biomass production and formulation protocols, we demonstrate the effectiveness, in vitro, of UV protectant compounds lignin (PC 1307) and Blankophor BBH in reducing OH 131.1 morbidity when cells were exposed to UV light from artificial sunlight.
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Affiliation(s)
- M S Warburton
- Department of General Medicine, New Cross Hospital, Wolverhampton WV6 7OQ.
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Abstract
Iodine is an important constituent of thyroid hormones and deficiency can lead to a range of problems depending on the degree and at what stage of life the deficiency occurs. We report a 10 day-old infant with a goitre, who presented with raised TSH on dried blood spot screening. It was observed that her mother also had a goitre. The mother was a vegan and, on dietary assessment, her iodine intake was extremely low. Both mother and infant had abnormal thyroid function tests. Mother was given Lugol's iodine and her thyroid function tests normalised. Her baby was initially prescribed thyroxine on the basis of the raised screening TSH. This was subsequently withdrawn at the age of 2 weeks, following a normal plasma TSH. Thyroid function tests remained normal and the goitre disappeared by the age of 2 months. Iodine deficiency is uncommon in the Western World. However the incidence may be rising in otherwise iodine replete areas, particularly in those who adhere to restrictive and unusual diets. In the case of pregnant mothers their unborn child's health is in danger. This report demonstrates the need to ascertain maternal diets early in antenatal care, and supplement if necessary to avoid risk to their own health and that of their offspring.
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Affiliation(s)
- M G Shaikh
- New Cross Hospital, Wolverhampton, Birmingham Children 's Hospital, UK.
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Pearson S, Jackson MA, Rylance PB. Sclerosing peritonitis complicating continuous ambulatory peritoneal dialysis managed by hemodialysis and home parenteral nutrition. Clin Nephrol 2002; 58:244-6. [PMID: 12356196 DOI: 10.5414/cnp58244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A 47-year-old dialysis patient developed severe sclerosing peritonitis. The patient has been unable to take any nutrition by mouth for 27 months. She has been maintained daily on home parenteral nutrition and hemodialysis 3 times per week. It has been possible for her to have a good quality of life and to maintain good nutritional status.
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Affiliation(s)
- S Pearson
- Renal Unit, New Cross Hospital Wolverhampton, United Kingdom.
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Aeschbach D, Postolache TT, Sher L, Matthews JR, Jackson MA, Wehr TA. Evidence from the waking electroencephalogram that short sleepers live under higher homeostatic sleep pressure than long sleepers. Neuroscience 2001; 102:493-502. [PMID: 11226688 DOI: 10.1016/s0306-4522(00)00518-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We used the waking electroencephalogram to study the homeostatic sleep regulatory process in human short sleepers and long sleepers. After sleeping according to their habitual schedule, nine short sleepers (sleep duration < 6 h) and eight long sleepers (> 9 h) were recorded half-hourly during approximately 40 h of wakefulness in a constant routine protocol. Within the frequency range of 0.25-20.0 Hz, spectral power density in the 5.25-9.0 and 17.25-18.0 Hz ranges was higher in short sleepers than in long sleepers. In both groups, increasing time awake was associated with an increase of theta/low-frequency alpha activity (5.25-9.0 Hz), whose kinetics followed a saturating exponential function. The time constant did not differ between groups and was similar to the previously obtained time constant of the wake-dependent increase of slow-wave activity (0.75-4.5 Hz) in the sleep electroencephalogram. In addition, the time constant of the decrease of slow-wave activity during extended recovery sleep following the constant routine did not differ between groups. However, short sleepers showed an abiding enhancement of theta/low-frequency alpha activity during wakefulness after recovery sleep that was independent of the homeostatic process. It is concluded that, while the kinetics of the homeostatic process do not differ between the two groups, short sleepers live under and tolerate higher homeostatic sleep pressure than long sleepers. The homeostat-independent enhancement of theta/low-frequency alpha activity in the waking electroencephalogram in the short sleepers may be genetically determined or be the result of long-term adaptation to chronically short sleep.
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Affiliation(s)
- D Aeschbach
- Section on Biological Rhythms, Intramural Research Program, National Institute of Mental Health, Bethesda, MD 20892, USA.
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Olson LC, Jackson MA, Bratcher D. Treatment of otitis media. Pediatr Infect Dis J 2001; 20:468-9. [PMID: 11332688 DOI: 10.1097/00006454-200104000-00033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
A child with malaria from a chloroquine-resistant area received an accidental overdose of chloroquine administered by a parent. Application of pharmacokinetics permitted definitive treatment with mefloquine in a safe and effective manner.
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Affiliation(s)
- J A Lowry
- Division of Clinical Pharmacology and Toxicology, Children's Mercy Hospital and Clinics, Kansas City, MO 64108, USA
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Abstract
In this paper, the metabolism and genetic toxicity of 1,3-butadiene (BD) and its oxidative metabolites in humans and rodents is reviewed with attention to newer data that have been published since the latest evaluation of BD by the International Agency for Research on Cancer (IARC). The oxidative metabolism of BD in mice, rats and humans is compared with emphasis on the major pathways leading to the reactive intermediates 1,2-epoxy-3-butene (EB), 1,2:3, 4-diepoxybutane (DEB), and 3,4-epoxy-1,2-butanediol (EBdiol). Results from recent studies of DNA and hemoglobin adducts indicate that EBdiol may play a more significant role in the toxicity of BD than previously thought. All three metabolites are capable of reacting with macromolecules, such as DNA and hemoglobin, and have been shown to induce a variety of genotoxic effects in mice and rats as well as in human cells in vitro. DEB is clearly the most potent of these genotoxins followed by EB, which in turn is more potent than EBdiol. Studies of mutations in lacI and lacZ mice and of the Hprt mutational spectrum in rodents and humans show that mutations at G:C base pairs are critical events in the mutagenicity of BD. In-depth analyses of the mutational spectra induced by BD and/or its oxidative metabolites should help to clarify which metabolite(s) are associated with specific mutations in each animal species and which mutational events contribute to BD-induced carcinogenicity. While the quantitative relationship between exposure to BD, its genotoxicity, and the induction of cancer in occupationally exposed humans remains to be fully established, there is sufficient data currently available to demonstrate that 1,3-butadiene is a probable human carcinogen.
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Affiliation(s)
- M A Jackson
- Alpha-Gamma Technologies Inc., Raleigh, NC 27609, USA
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38
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Karkera JD, Ayache S, Ransome RJ, Jackson MA, Elsayem AF, Sridhar R, Detera-Wadleigh SD, Wadleigh RG. Refinement of regions with allelic loss on chromosome 18p11.2 and 18q12.2 in esophageal squamous cell carcinoma. Clin Cancer Res 2000; 6:3565-9. [PMID: 10999745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Esophageal cancer ranks among the 10 most common cancers worldwide and is almost invariably fatal. The detailed genetic repertoire involved in esophageal carcinogenesis has not been defined. We have shown previously that the esophageal squamous cell carcinoma genome exhibits a frequent loss of heterozygosity (LOH) in the pericentromeric region of chromosome 18. To construct a fine deletion map, we screened 76 new samples composed of microdissected esophageal squamous cell carcinoma and matched morphologically normal epithelial cells using closely spaced markers. Maximal LOH frequency (54%) was displayed by D18S542 on 18p11.2. The pattern of LOH in selected patients indicated that the short region of overlap extends 3 cM on either side of D18S542. On the long arm of chromosome 18, the highest frequency of allelic loss (42%) was detected by D18S978 on 18q12.2-q21.1. This analysis revealed a short region of overlap of approximately 0.8 cM. These findings further implicate unreported tumor suppressor genes encoded by 18p11.2 and 18q12.2 in esophageal squamous cell carcinogenesis and they indicate a refinement of their map location.
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Affiliation(s)
- J D Karkera
- Medical Oncology Section, Department of Veterans Affairs Medical Center, Washington, DC 20422, USA
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39
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Jackson MA, Holland MR, Nicholas J, Lodwick R, Forster D, Macdonald IA. Hemodialysis-induced hypoglycemia in diabetic patients. Clin Nephrol 2000; 54:30-4. [PMID: 10939754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND The authors have previously reported asymptomatic hypoglycemia in non-diabetic patients on hemodialysis. The present study was designed to assess the effect of hemodialysis on plasma glucose, glucagon, cortisol and catecholamines in diabetic patients. METHODS Eighteen diabetic patients with chronic renal failure were hemodialyzed using a glucose-free dialysis fluid. They did not take any medication prior to dialysis and were asked not to eat during the first hour on hemodialysis. Blood and dialysate were sampled at regular intervals during the first hour of dialysis for analysis. RESULTS Plasma glucose fell below 4.0 mmol/l (72 mg/dl) in 7 of the 18 patients, below 3.5 mmol/l (63 mg/dl) in 3 and below 3.0 mmol/l (54 mg/dl) in one. The lowest recorded value was 2.8 mmol/l (50 mg/dl). The mean glucose loss in the waste dialysate was 9.2 g/h. In none of the group of 7 patients whose plasma glucose fell below 4.0 mmol/l (72 mg/dl) did symptoms of hypoglycemia occur. When 6 patients from this group were subsequently dialyzed with a dialysis fluid containing 5.5 mmol/l (100 mg/dl) glucose, their plasma glucose became stabilized within the fasting reference range. There were no significant hormonal changes during the dialysis or between non-hypoglycemic and hypoglycemic patients. CONCLUSIONS Patients undergoing hemodialysis may become hypoglycemic and not be aware of it. There is no hormonal imbalance causing the hypoglycemia and the hormonal response to the hypoglycemia is blunted. Patients with an initial plasma glucose of 5.5 mmol/l (100 mg/dl) or less who are hemodialyzed and who do not eat during dialysis may be particularly at risk, especially if they are on insulin or taking glucose-lowering medication. These should be dialyzed with a dialysis fluid containing at least 5.5 mmol/l (100 mg/dl) glucose.
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Affiliation(s)
- M A Jackson
- Renal Dialysis Unit, New Cross Hospital, Wolverhampton, England
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40
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Abstract
Diazemuls is a very powerful anxiolytic agent with sedating and anti-epileptogenic properties. Unfortunately, until now it has not been possible to give Diazemuls accurately and safely as an infusion. A new delivery system ensures that, as an infusion, this drug is potentially very effective in treating patients with terminal agitation, status epilepticus, drug and alcohol withdrawal.
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Affiliation(s)
- M A Jackson
- Renal Dialysis Unit, New Cross Hospital, Wolverhampton
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41
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McMahon J, Hruby G, O'Brien CJ, McNeil EB, Bagia JS, Clifford AR, Jackson MA. Neck dissection and ipsilateral radiotherapy in the management of cervical metastatic carcinoma from an unknown primary. Aust N Z J Surg 2000; 70:263-8. [PMID: 10779057 DOI: 10.1046/j.1440-1622.2000.01804.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND In a small proportion of patients presenting with metastases to cervical lymph nodes the primary cancer remains occult despite thorough evaluation. The present report examines patterns of failure and outcome following an initial treatment strategy directed principally at the clinically involved side of the neck. METHODS From a prospectively compiled computerized database 38 patients were identified with metastatic squamous cell carcinoma from an occult primary site. These patients were evaluated with respect to initial treatment, subsequent detection of a primary tumour, neck recurrence and survival characteristics. RESULTS Thirty-seven of 38 patients were treated with curative intent and all had neck dissection. Adjuvant radiotherapy was given to 34 of the 37 (90%; 32 postoperatively and two pre-operatively). Radiotherapy was directed at the ipsilateral neck alone in 24 patients while 10 received comprehensive treatment to both sides of the neck and potential occult primary sites. The rate of control of disease in the ipsilateral neck was 91% while the failure rate in the contralateral neck was 16% (six patients). A primary cancer was ultimately identified in five patients (13%). Disease-specific survival was 63% at 4 years. Clinical N3 stage, extracapsular tumour extension and involved surgical margins predicted for poorer survival on univariate analysis. Analysis using multiple risk factors found that only involved surgical margins predicted for treatment failure. CONCLUSIONS Despite generally advanced disease at presentation, patients presenting with cervical metastasis from an unknown primary carcinoma have a reasonable survival expectation and aggressive treatment is warranted, but approximately half will develop recurrent disease. Careful follow-up is required if effective salvage treatment is to be instituted.
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Affiliation(s)
- J McMahon
- Department of Head and Neck Surgery, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
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42
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Aeschbach D, Matthews JR, Postolache TT, Jackson MA, Giesen HA, Wehr TA. Two circadian rhythms in the human electroencephalogram during wakefulness. Am J Physiol 1999; 277:R1771-9. [PMID: 10600925 DOI: 10.1152/ajpregu.1999.277.6.r1771] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The influence of the circadian pacemaker and of the duration of time awake on the electroencephalogram (EEG) was investigated in 19 humans during approximately 40 h of sustained wakefulness. Two circadian rhythms in spectral power density were educed. The first rhythm was centered in the theta band (4.25-8.0 Hz) and exhibited a minimum approximately 1 h after the onset of melatonin secretion. The second rhythm was centered in the high-frequency alpha band (10.25-13.0 Hz) and exhibited a minimum close to the body temperature minimum. The latter rhythm showed a close temporal association with the rhythms in subjective alertness, plasma melatonin, and body temperature. In addition, increasing time awake was associated with an increase of power density in the 0.25- to 9.0-Hz and 13.25- to 20. 0-Hz ranges. It is concluded that the waking EEG undergoes changes that can be attributed to circadian and homeostatic (i.e., sleep-wake dependent) processes. The distinct circadian variations of EEG activity in the theta band and in the high-frequency alpha band may represent electrophysiological correlates of different aspects of the circadian rhythm in arousal.
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Affiliation(s)
- D Aeschbach
- Section on Biological Rhythms, Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
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43
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Affiliation(s)
- L C Olson
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine and The Children's Mercy Hospital, USA
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44
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Dearfield KL, McCarroll NE, Protzel A, Stack HF, Jackson MA, Waters MD. A survey of EPA/OPP and open literature on selected pesticide chemicals. II. Mutagenicity and carcinogenicity of selected chloroacetanilides and related compounds. Mutat Res 1999; 443:183-221. [PMID: 10415440 DOI: 10.1016/s1383-5742(99)00019-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
With this effort, we continue our examination of data on selected pesticide chemicals and their related analogues that have been presented to the U.S. Environmental Protection Agency's (USEPA's) Office of Pesticide Programs (OPP). This report focuses on a group of selected chloroacetanilides and a few related compounds. As part of the registration process for pesticidal chemicals, interested parties (registrants) must submit toxicity information to support the registration including both mutagenicity and carcinogenicity data. Although this information is available to the public via Freedom of Information (FOI) requests to the OPP, publication in the scientific literature allows greater dissemination and examination of the data. For this Special Issue, graphic profiles have been prepared of the mutagenicity and carcinogenicity data available in the submissions to OPP. Also, a discussion is presented about how toxicity data are used to help establish tolerances (limits of pesticide residues in foods). The mutagenicity results submitted by registrants are supplemented by data on these chemicals from the open literature to provide a full perspective of their genetic toxicology. The group of chloroacetanilides reviewed here display a consistent pattern of mutagenic activity, probably mediated via metabolites. This mutagenic activity is a mechanistically plausible factor in the development of tumors seen in experimental animals exposed to this class of chemicals.
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Affiliation(s)
- K L Dearfield
- U.S. Environmental Protection Agency, Office of Research and Development (8103R), Washington, DC 20460, USA
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45
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Abstract
In 1969, the International Agency for Research on Cancer (IARC) initiated the Monographs Programme to evaluate the carcinogenic risk of chemicals to humans. Results from short-term mutagenicity tests were first included in the IARC Monographs in the mid-1970s based on the observation that most carcinogens are also mutagens, although not all mutagens are carcinogens. Experimental evidence at that time showed a strong correlation between mutagenicity and carcinogenicity and indicated that short-term mutagenicity tests are useful for predicting carcinogenicity. Although the strength of these correlations has diminished over the past 20 years with the identification of putative nongenotoxic carcinogens, such tests provide vital information for identifying potential human carcinogens and understanding mechanisms of carcinogenesis. The short-term test results for agents compiled in the EPA/IARC Genetic Activity Profile (GAP) database over nearly 15 years are summarized and reviewed here with regard to their IARC carcinogenicity classifications. The evidence of mutagenicity or nonmutagenicity based on a 'defining set' of test results from three genetic endpoints (gene mutation, chromosomal aberrations, and aneuploidy) is examined. Recommendations are made for assessing chemicals based on the strength of evidence from short-term tests, and the implications of this approach in identifying mutational mechanisms of carcinogenesis are discussed. The role of short-term test data in influencing the overall classification of specific compounds in recent Monograph volumes is discussed, particularly with reference to studies in human populations. Ethylene oxide is cited as an example.
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Affiliation(s)
- M D Waters
- US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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46
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Abstract
BACKGROUND During summer enteroviral meningitis is a common cause of febrile illness in children, who are typically hospitalized for 2 to 3 days if bacterial infection is suspected. It has been hypothesized that a sensitive polymerase chain reaction (PCR) assay could quickly confirm the diagnosis and subsequently decrease hospitalization costs. However, to have maximum impact results should be available within 24 h. This necessitates daily assays on small numbers of samples. METHODS We examined the clinical utility of a PCR assay during two summers, comparing length of stay and charges. Only during the second summer were results reported to clinicians. Case controls were patients with negative PCR assay results but uncomplicated, presumed viral infections. We determined the cost per case identified with and without pleocytosis as a screen for PCR testing. RESULTS During the first summer 25% (5/20) of patients with positive PCR assay results remained hospitalized for >2 days. During the second summer 10.2% (6 of 59) of children with positive enteroviral PCR assay results but 37.9% (25 of 66) of case controls remained hospitalized for >2 days. The mean length of hospitalization was significantly (P < 0.05) shorter for patients with positive PCR test results than for case controls. The material cost was approximately $238 per case identified. CONCLUSIONS PCR testing has clinical utility for diagnosis of enteroviral meningitis. Although the demands for daily testing make the test expensive, it appears to be cost-effective with savings related to shorter hospital stays.
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Affiliation(s)
- M S Hamilton
- Department of Pathology, The Children's Mercy Hospital, Kansas City, MO, USA
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47
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Jackson MA, Holland MR, Nicholas J, Talbot M, Spencer H, Lodwick R, Fuhrmann C, Forster D, Macdonald IA. Occult hypoglycemia caused by hemodialysis. Clin Nephrol 1999; 51:242-7. [PMID: 10230557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
BACKGROUND Previous studies have ignored hypoglycemia in patients undergoing hemodialysis. The fall in plasma glucose may not have been considered to be clinically relevant because the patients were asymptomatic. The present study was designed to assess the effect of hemodialysis on plasma glucose, insulin, glucagon, cortisol and catecholamines in non diabetic patients. METHODS 21 non diabetic patients with chronic renal failure were hemodialyzed using a glucose-free dialysis fluid. They did not take any medication prior to dialysis and were asked not to eat during the first hour on hemodialysis. Blood and dialysate fluid was sampled at regular intervals during the first hour of dialysis for analysis. RESULTS Plasma glucose fell below 4.0 mmol/l (72 mg/dl) in 9 of the 21 patients, below 3.5 mmol/l (63 mg/dl) in 6 and below 3.0 mmol/l (54 mg/dl) in 3. The lowest recorded value was 2.1 mmol/l (38 mg/dl). The mode glucose loss in the waste dialysate fluid was 6 g/h. In the group of 9 patients whose plasma glucose fell below 4.0 mmol/l (72 mg/dl), no symptoms of hypoglycemia were shown but 4 of the 7 patients who felt very hungry and ate were in this group. When 7 patients from this group were subsequently dialysed with a dialysis fluid containing 5.5 mmol/l (100 mg/dl) glucose, their plasma glucose became stabilized within the fasting reference range. There were no significant hormonal changes during the dialysis or between euglycemic and hypoglycemic patients. CONCLUSIONS Patients undergoing hemodialysis may become hypoglycemic and not be aware of it. There is no hormonal imbalance causing the hypoglycemia and the hormonal response to the hypoglycemia is blunted. Patients with an initial plasma glucose of 4.5 mmol/l (81 mg/dl) or less who are hemodialyzed and who do not eat during dialysis may be particularly at risk. They should be dialysed with a dialysis fluid containing at least 5.5 mmol/l (100 mg/dl) glucose.
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Affiliation(s)
- M A Jackson
- Renal Dialysis Unit, New Cross Hospital, Wolverhampton, England
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48
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Waters MD, Stack HF, Jackson MA. Short-term tests for defining mutagenic carcinogens. IARC Sci Publ 1999:499-536. [PMID: 10353401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
The results of short-term tests for mutagenicity were first included in the IARC Monographs in the mid-1970s on the basis of the observation that most carcinogens are also mutagens, although not all mutagens are carcinogens. The experimental evidence at that time showed a strong correlation between mutagenicity and carcinogenicity and indicated that the short-term tests were useful for predicting carcinogenicity. Although the correlations have become weaker over the past 20 years, and with them the predictive value of short-term tests, such tests still provide vital information for identifying and understanding mechanisms involved in carcinogenicity. The results of short-term tests compiled in the US Environmental Protection Agency-IARC Genetic Activity Profile database over the past 12 years are summarized and reviewed here in relation to the classification of agents for carcinogenicity within the system used at IARC. The role of the information from short-term tests in making overall classifications of specific compounds in recent Monographs is discussed. The usefulness of data on three genetic end-points, gene mutation, chromosomal aberrations and aneuploidy, and the criteria for mutagenicity and lack of mutagenicity based on a 'defining set' of test results are examined. Recommendations are made for assessing chemicals on the basis of the strength of the evidence from short-term tests, and the implications of this approach for identifying putative mutational mechanisms of carcinogenicity are discussed.
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Affiliation(s)
- M D Waters
- US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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49
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Jackson MA, Frymier JS, Wilkinson BJ, Zorner P, Evans S. Growth requirements for production of stable cells of the bioherbicidal bacterium Xanthomonas campestris. J Ind Microbiol Biotechnol 1998. [DOI: 10.1038/sj.jim.2900580] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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50
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Vandenberg JD, Jackson MA, Lacey LA. Relative efficacy of blastospores and aerial conidia of Paecilomyces fumosoroseus against the russian wheat aphid. J Invertebr Pathol 1998; 72:181-3. [PMID: 9709022 DOI: 10.1006/jipa.1998.4772] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- J D Vandenberg
- USDA Agricultural Research Service, U.S. Plant, Soil and Nutrition Laboratory, Tower Road, Ithaca, New York, 14850, USA
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