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Karakasheva TA, Zhou Y, Xie HM, Soto GE, Johnson TD, Stoltz MA, Roach DM, Nema N, Umeweni CN, Naughton K, Dolinsky L, Pippin JA, Wells AD, Grant SFA, Ghanem L, Terry N, Muir AB, Hamilton KE. Patient-derived Colonoids From Disease-spared Tissue Retain Inflammatory Bowel Disease-specific Transcriptomic Signatures. Gastro Hep Adv 2023; 2:830-842. [PMID: 37736163 PMCID: PMC10512767 DOI: 10.1016/j.gastha.2023.05.003] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
BACKGROUND AND AIMS A key histopathological feature of inflammatory bowel disease is damage to the mucosa, including breakdown of the epithelial barrier. Human enteroids and colonoids are a critical bench-to-bedside tool for studying the epithelium in inflammatory bowel disease. The goal of the current study was to define transcriptional differences in healthy versus diseased subjects that are sustained in enteroids and colonoids, including from disease-spared tissue. METHODS Biopsies and matching enteroid or colonoid cultures from pediatric patients with ileal Crohn disease (N = 6) and control subjects (N = 17) were subjected to RNA sequencing followed by bioinformatic and machine learning analyses. Late passage enteroids were exposed to cytokines to assess durable transcriptional differences. RESULTS We observed substantial overlap of pathways upregulated in Crohn disease in enteroids and ileal biopsies, as well as colonoids and rectal biopsies. KEGG pathways for cytokine-cytokine receptor interaction, chemokine signaling, protein export, and Toll-like receptor signaling were upregulated in both ileal and rectal biopsies, as well as enteroids and colonoids. In vitro cytokine exposure reactivated genes previously increased in biopsies. Machine learning predicted biopsy location (100% accuracy) and donor disease status (83% accuracy). A random forest classifier generated using ileal enteroids identified rectal colonoids from ileal Crohn disease subjects with 80% accuracy. CONCLUSION We confirmed transcriptional profiles of Crohn disease biopsies are expressed in enteroids and colonoids. Furthermore, transcriptomic data from disease-spared rectal tissue can identify patients with ileal Crohn disease. Our data support the use of patient enteroids and colonoids as critical translational tools for the study of inflammatory bowel disease.
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Affiliation(s)
- Tatiana A. Karakasheva
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Yusen Zhou
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Hongbo M. Xie
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Gloria E. Soto
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Tiana D. Johnson
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Madison A. Stoltz
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Daana M. Roach
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Noor Nema
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Chizoba N. Umeweni
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Kaitlyn Naughton
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Lauren Dolinsky
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - James A. Pippin
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Andrew D. Wells
- Center for Spatial and Functional Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Struan F. A. Grant
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Center for Spatial and Functional Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Division of Diabetes and Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Louis Ghanem
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- Department of Immunology, Translational Sciences and Medicine, Janssen Research and Development, LLC, Spring House, Pennsylvania
| | - Natalie Terry
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- Department of Immunology, Clinical Development, Janssen Research and Development, LLC, Spring House, Pennsylvania
| | - Amanda B. Muir
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Kathryn E. Hamilton
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Sonzogni AA, McCutchan EA, Johnson TD, Dimitriou P. Effects of Fission Yield Data in the Calculation of Antineutrino Spectra for ^{235}U(n,fission) at Thermal and Fast Neutron Energies. Phys Rev Lett 2016; 116:132502. [PMID: 27081973 DOI: 10.1103/physrevlett.116.132502] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Indexed: 06/05/2023]
Abstract
Fission yields form an integral part of the prediction of antineutrino spectra generated by nuclear reactors, but little attention has been paid to the quality and reliability of the data used in current calculations. Following a critical review of the thermal and fast ENDF/B-VII.1 ^{235}U fission yields, deficiencies are identified and improved yields are obtained, based on corrections of erroneous yields, consistency between decay and fission yield data, and updated isomeric ratios. These corrected yields are used to calculate antineutrino spectra using the summation method. An anomalous value for the thermal fission yield of ^{86}Ge generates an excess of antineutrinos at 5-7 MeV, a feature which is no longer present when the corrected yields are used. Thermal spectra calculated with two distinct fission yield libraries (corrected ENDF/B and JEFF) differ by up to 6% in the 0-7 MeV energy window, allowing for a basic estimate of the uncertainty involved in the fission yield component of summation calculations. Finally, the fast neutron antineutrino spectrum is calculated, which at the moment can only be obtained with the summation method and may be relevant for short baseline reactor experiments using highly enriched uranium fuel.
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Affiliation(s)
- A A Sonzogni
- National Nuclear Data Center, Building 817, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - E A McCutchan
- National Nuclear Data Center, Building 817, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - T D Johnson
- National Nuclear Data Center, Building 817, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - P Dimitriou
- NAPC-Nuclear Data Section, International Atomic Energy Agency, P.O. Box 100, Vienna A-1400, Austria
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Ungerleider JL, Johnson TD, Rao N, Christman KL. Fabrication and characterization of injectable hydrogels derived from decellularized skeletal and cardiac muscle. Methods 2015; 84:53-9. [PMID: 25843605 DOI: 10.1016/j.ymeth.2015.03.024] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [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: 01/05/2015] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 12/31/2022] Open
Abstract
Biomaterials, which can contain appropriate biomechanical and/or biochemical cues, are increasingly being investigated as potential scaffolds for tissue regeneration and/or repair for treating myocardial infarction, heart failure, and peripheral artery disease. Specifically, injectable hydrogels are touted for their minimally invasive delivery, ability to self-assemble in situ, and capacity to encourage host tissue regeneration. Here we present detailed methods for fabricating and characterizing decellularized injectable cardiac and skeletal muscle extracellular matrix (ECM) hydrogels. The ECM derived hydrogels have low cellular and DNA content, retain sulfated glycosaminoglycans and other extracellular matrix proteins such as collagen, gel at physiologic temperature and pH, and assume a nanofibrous architecture. These injectable hydrogels are amenable to minimally invasive, tissue specific biomaterial therapies for treating myocardial infarction and peripheral artery disease.
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Affiliation(s)
- J L Ungerleider
- Department of Bioengineering, Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA
| | - T D Johnson
- Department of Bioengineering, Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA
| | - N Rao
- Department of Bioengineering, Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA
| | - K L Christman
- Department of Bioengineering, Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA.
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Srinivasan A, Galbán CJ, Johnson TD, Chenevert TL, Ross BD, Mukherji SK. Utility of the k-means clustering algorithm in differentiating apparent diffusion coefficient values of benign and malignant neck pathologies. AJNR Am J Neuroradiol 2009; 31:736-40. [PMID: 20007723 DOI: 10.3174/ajnr.a1901] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Does the K-means algorithm do a better job of differentiating benign and malignant neck pathologies compared to only mean ADC? The objective of our study was to analyze the differences between ADC partitions to evaluate whether the K-means technique can be of additional benefit to whole-lesion mean ADC alone in distinguishing benign and malignant neck pathologies. MATERIAL AND METHODS MR imaging studies of 10 benign and 10 malignant proved neck pathologies were postprocessed on a PC by using in-house software developed in Matlab. Two neuroradiologists manually contoured the lesions, with the ADC values within each lesion clustered into 2 (low, ADC-ADC(L); high, ADC-ADC(H)) and 3 partitions (ADC(L); intermediate, ADC-ADC(I); ADC(H)) by using the K-means clustering algorithm. An unpaired 2-tailed Student t test was performed for all metrics to determine statistical differences in the means of the benign and malignant pathologies. RESULTS A statistically significant difference between the mean ADC(L) clusters in benign and malignant pathologies was seen in the 3-cluster models of both readers (P = .03 and .022, respectively) and the 2-cluster model of reader 2 (P = .04), with the other metrics (ADC(H), ADC(I); whole-lesion mean ADC) not revealing any significant differences. ROC curves demonstrated the quantitative differences in mean ADC(H) and ADC(L) in both the 2- and 3-cluster models to be predictive of malignancy (2 clusters: P = .008, area under curve = 0.850; 3 clusters: P = .01, area under curve = 0.825). CONCLUSIONS The K-means clustering algorithm that generates partitions of large datasets may provide a better characterization of neck pathologies and may be of additional benefit in distinguishing benign and malignant neck pathologies compared with whole-lesion mean ADC alone.
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Affiliation(s)
- A Srinivasan
- Department of Radiology, University of Michigan Health System, Ann Arbor, 48109, USA.
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Abstract
TOPIC Crisis situations of youth in treatment settings may require restraints. Restraints should only be used in situations where there is imminent danger to the child and when there is no alternative. They are meant to maintain the child's safety, but there is risk for respiratory compromise. PURPOSE Nursing care of children in restraints must include respiratory assessment and, when indicated, immediate intervention to prevent disastrous outcomes. SOURCES Review using PubMed and established texts confirms that clinical skills and knowledge is essential to child and adolescent psychiatric nursing. CONCLUSIONS Clinical assessment and awareness of risks in physical restraints is essential for the safety and well-being of the child.
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Affiliation(s)
- T D Johnson
- Lupine Creative Consulting, Inc., and University of Rochester, School of Nursing, Rochester, NY, USA.
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Mellström DD, Sörensen OH, Goemaere S, Roux C, Johnson TD, Chines AA. Seven years of treatment with risedronate in women with postmenopausal osteoporosis. Calcif Tissue Int 2004; 75:462-8. [PMID: 15455188 DOI: 10.1007/s00223-004-0286-7] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2004] [Accepted: 07/01/2004] [Indexed: 10/26/2022]
Abstract
The effects of 7 years of risedronate treatment were evaluated in a second 2-year extension of a 3-year vertebral fracture study in women with osteoporosis. For the first 5 years of the study, women received risedronate 5 mg/day or placebo according to the original randomization, with maintenance of blinding. All the women who entered into the 6-7 years extension study received risedronate 5 mg/day. Endpoints included vertebral and nonvertebral fracture assessments, changes in biochemical markers of bone turnover, and bone mineral density (BMD) measurements. A total of 164 women (placebo/risedronate group, 81; risedronate group, 83) entered the 6-7 years extension study and 136 (83%) completed the study. Annualized incidence of new vertebral fractures during the 6-7 years was similar between the 2 treatment groups (3.8%). The incidence of vertebral fractures did not change in the 7-year risedronate group during the 6-7 years as compared to 4-5 years, while a significant reduction was observed in the placebo group that switched to risedronate treatment during years 6-7. The incidence of nonvertebral fractures was 7.4% and 6.0% in the placebo/risedronate and risedronate groups, respectively, during years 6-7. Urinary N-telopeptide decreased from baseline by 54% and 63% at 3 months and 7 years, respectively, in the risedronate group. The increases in BMD from baseline after 5 years of risedronate treatment were maintained or increased further during years 6-7; lumbar spine BMD after 5 and 7 years of risedronate treatment increased from baseline by 8.8% and 11.5%, respectively, for this extension study population. Risedronate was well tolerated and the occurrence of upper gastrointestinal adverse events was low. After 7 years of continuous risedronate treatment there were significant increases in BMD and decreases in bone turnover to within premenopausal levels and there was no indication of any loss of anti-fracture efficacy.
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Affiliation(s)
- D D Mellström
- Department of Geriatric Medicine, University of Göteborg, Sweden
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Dufresne TE, Chmielewski PA, Manhart MD, Johnson TD, Borah B. Risedronate preserves bone architecture in early postmenopausal women in 1 year as measured by three-dimensional microcomputed tomography. Calcif Tissue Int 2003; 73:423-32. [PMID: 12964065 DOI: 10.1007/s00223-002-2104-4] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2002] [Accepted: 03/03/2003] [Indexed: 11/28/2022]
Abstract
Risedronate reduces the risk of vertebral fractures by up to 70% within the first year of treatment. Increases in bone mineral density or decreases in bone turnover markers explain only a portion of the anti-fracture effect, suggesting that other factors, such as changes in trabecular bone architecture, also play a role. Our objective was to determine the effects of risedronate on bone architecture by analyzing iliac crest bone biopsy specimens using three-dimensional microcomputed tomography (3-D micro CT). Biopsy specimens were obtained at baseline and after 1 year of treatment from women enrolled in a double-blind, placebo-controlled study of risedronate 5 mg daily for the prevention of early postmenopausal bone loss. Trabecular architecture deteriorated in the placebo group (n = 12), as indicated by a 20.3% decrease in bone volume (25.1% vs. 20.0%, P = 0.034), a 13.5% decrease in trabecular number (1.649 vs. 1.426 mm(-1), P = 0.052), a 13.1% increase in trabecular separation (605 vs. 684 microm, P = 0.056), and an 86.2% increase in marrow star volume (3.251 vs. 6.053 mm(3), P = 0.040) compared with baseline values. These changes in architectural parameters occurred in the presence of a concomitant decrease from baseline in lumbar spine bone mineral density (-3.3%, P = 0.002), as measured by dual energy x-ray absorptiometry. There was no statistically significant ( P < 0.05) deterioration in the risedronate-treated group (n = 14) over the 1-year treatment period. Comparing the actual changes between the two groups, the placebo group experienced decreases in bone volume (placebo, -5.1%; risedronate, +3.5%; P = 0.011), trabecular thickness (placebo, -20 microm; risedronate, +23 microm; P = 0.032), and trabecular number (placebo, -0.223 mm(-1); risedronate, +0.099 mm(-1); P = 0.010), and increases in percent plate (placebo, +2.79%; risedronate, -3.23%; P = 0.018), trabecular separation (placebo, +79 microm; risedronate, -46 microm; P = 0.010) and marrow star volume (placebo, +2.80 mm(3); risedronate, -2.08mm(3); P = 0.036), compared with the risedronate group. These data demonstrate that trabecular architecture deteriorated significantly in this cohort of early postmenopausal women, and that this deterioration was prevented by risedronate. Although there is no direct link in this study between fracture and preservation of architecture, it is reasonable to infer that the preservation of bone architecture may play a role in risedronate's anti-fracture efficacy.
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Affiliation(s)
- T E Dufresne
- Procter & Gamble Pharmaceuticals, Cincinnati, OH 45040, USA.
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Swindle CS, Tran KT, Johnson TD, Banerjee P, Mayes AM, Griffith L, Wells A. Epidermal growth factor (EGF)-like repeats of human tenascin-C as ligands for EGF receptor. J Cell Biol 2001; 154:459-68. [PMID: 11470832 PMCID: PMC2150768 DOI: 10.1083/jcb.200103103] [Citation(s) in RCA: 230] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2001] [Revised: 05/24/2001] [Accepted: 05/29/2001] [Indexed: 01/25/2023] Open
Abstract
Signaling through growth factor receptors controls such diverse cell functions as proliferation, migration, and differentiation. A critical question has been how the activation of these receptors is regulated. Most, if not all, of the known ligands for these receptors are soluble factors. However, as matrix components are highly tissue-specific and change during development and pathology, it has been suggested that select growth factor receptors might be stimulated by binding to matrix components. Herein, we describe a new class of ligand for the epidermal growth factor (EGF) receptor (EGFR) found within the EGF-like repeats of tenascin-C, an antiadhesive matrix component present during organogenesis, development, and wound repair. Select EGF-like repeats of tenascin-C elicited mitogenesis and EGFR autophosphorylation in an EGFR-dependent manner. Micromolar concentrations of EGF-like repeats induced EGFR autophosphorylation and activated extracellular signal-regulated, mitogen-activated protein kinase to levels comparable to those induced by subsaturating levels of known EGFR ligands. EGFR-dependent adhesion was noted when the ligands were tethered to inert beads, simulating the physiologically relevant presentation of tenascin-C as hexabrachion, and suggesting an increase in avidity similar to that seen for integrin ligands upon surface binding. Specific binding to EGFR was further established by immunofluorescence detection of EGF-like repeats bound to cells and cross-linking of EGFR with the repeats. Both of these interactions were abolished upon competition by EGF and enhanced by dimerization of the EGF-like repeat. Such low affinity behavior would be expected for a matrix-"tethered" ligand; i.e., a ligand which acts from the matrix, presented continuously to cell surface EGF receptors, because it can neither diffuse away nor be internalized and degraded. These data identify a new class of "insoluble" growth factor ligands and a novel mode of activation for growth factor receptors.
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Affiliation(s)
- C S Swindle
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Abstract
New analogues of paclitaxel (1a, active constituent of Taxol) were synthesized containing an epoxide at the C-10 position. The introduction of the epoxide was carried out by selective removal of the C10-acetate followed by protection of the C2'- and C7-hydroxyl groups. After oxidation to yield a ketone at the C10-position, this intermediate was reacted with dimethylsulfonium ylide. Deprotection and further manipulations provide the C10-spiro epoxide of paclitaxel (1b) and the corresponding C7-MOM ether (1c).
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Affiliation(s)
- M A Walker
- Bristol-Myers Squibb, Pharmaceutical Research Institute, Richard L. Gelb Center for Pharmaceutical Research and Development, 5 Research Parkway, 06492, Wallingford, CT, USA.
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Abstract
The effect of luminal shear stress was studied in cerebral arteries and arterioles. Middle cerebral arteries (MCA) and penetrating arterioles (PA) were isolated from male Long-Evans rats, mounted in a tissue bath, and pressurized. After the development of spontaneous tone, inside diameters were 186 +/- 5 microm (n = 28) for MCA and 65 +/- 3 microm (n = 37) for PA. MCA and PA constricted approximately 20% with increasing flow. Flow-induced constriction persisted in MCA and PA after removal of the endothelium. After removal of the endothelium, the luminal application of a polypeptide containing the Arg-Gly-Asp amino acid sequence (inhibitor of integrin attachment) abolished the flow-induced constriction. Similarly, an antibody specific for the beta(3)-chain of the integrin complex significantly inhibited the flow-induced constriction. The shear stress-induced constriction was accompanied by an increase in vascular smooth muscle Ca(2+). For example, a shear stress of 20 dyn/cm(2) constricted MCA 8% (n = 5) and increased Ca(2+) from 209 +/- 17 to 262 +/- 29 nM (n = 5). We conclude that isolated cerebral arteries and arterioles from the rat constrict to increased shear stress. Because the endothelium is not necessary for the response, the shear forces must be transmitted across the endothelium, presumably by the cytoskeletal matrix, to elicit constriction. Integrins containing the beta(3)-chain are involved with the shear stress-induced constrictions.
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Affiliation(s)
- R M Bryan
- Department of Anesthesiology, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA.
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Abstract
In the middle cerebral artery (MCA), the presence of nitric oxide (NO) is responsible for maintaining a more dilated state than in its absence during increases in extracellular K(+) and osmolality. The purpose of the present study was to determine whether the involvement of NO was due to (a) a direct effect of the K(+)/osmolality (K(hyper)) on the endothelium or (b) a 'permissive' role of NO. MCAs (approximately 210 microm o.d.) were isolated, cannulated with glass micropipettes, and pressurized to 85 mmHg. When K(+) (KCl) in the extraluminal bath was increased to 21 mM, the diameter increased by 15-20% with the magnitude of dilation diminishing with further increases in K(hyper). The addition of N(G)-nitro-L-arginine methyl ester (L-NAME, 10(-5) mM), an inhibitor of nitric oxide synthase, had no significant effect on dilations at lower K(hyper) concentrations but constricted the arteries relative to the control at 51, 66, and 81 mM K(hyper). In the presence of L-NAME, the addition of an exogenous NO donor, S-nitroso-N-acetylpenicillamine (SNAP, 10(-8) M) or an analog of cGMP, 8-bromo-cGMP (6x10(-5) M), tended to restore the response of K(hyper)to near the original response. We conclude that the basal release of NO from the endothelium plays a permissive role in the K(hyper)-induced response.
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Affiliation(s)
- E M Golding
- Department of Anesthesiology, Baylor College of Medicine, One Baylor Plaza, Suite 434D, Houston, TX 77030, USA.
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Abstract
After traumatic brain injury, extracellular K(+) in brain can dramatically increase. We studied the effects of increased K(+) on the isolated pressurized rat middle cerebral artery (MCA). MCAs (200-250 microm OD) were isolated, cannulated with glass micropipettes, and pressurized. K(+) was increased in the extraluminal bath using three paradigms: (1) isotonic K(+) (K(iso)) where increases in K(+) were offset by decreases in Na(+), (2) hypertonic K(+) (K(hyper)) where K(+) was increased without a concomitant adjustment of Na(+), and (3) K(suc), a solution using K(iso) but with the addition of sucrose to obtain a hypertonic solution. Increases in K(+) in the extraluminal bath produced significant dilations (approximately 20%) at 21 mM K(+) in all three groups (K(iso), K(hyper), and K(suc)). With the K(hyper) and K(suc) groups, the magnitude of the dilation diminished with further increases in K(+). L-NAME (10(-5) M), an inhibitor of nitric oxide synthase, had no effect on the response of the K(hyper) and K(suc) groups at 21 mM but significantly enhanced constrictions of the MCAs above 40 mM K(+) compared to the control. The K(iso) group was not affected by L-NAME at any K(+) concentration and showed profound constrictions above 40 mM K(+). We conclude that changes in the K(+) concentration and osmolality of the extracellular fluid may have profound effects on the cerebral vasculature.
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Affiliation(s)
- E M Golding
- Department of Anesthesiology, Baylor College of Medicine, Houston, TX 77030, USA.
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Chang L, Munakata J, Mayer EA, Schmulson MJ, Johnson TD, Bernstein CN, Saba L, Naliboff B, Anton PA, Matin K. Perceptual responses in patients with inflammatory and functional bowel disease. Gut 2000; 47:497-505. [PMID: 10986209 PMCID: PMC1728092 DOI: 10.1136/gut.47.4.497] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Enhanced visceral sensitivity following a transient inflammatory process in the gut has been postulated as an aetiological mechanism of irritable bowel syndrome (IBS). In this study we compared perceptual responses to rectosigmoid distension in patients with mild chronic inflammation of the rectum (ulcerative colitis (UC)) and patients without mucosal inflammation (IBS) to determine if chronic low grade mucosal inflammation may be a plausible explanation for rectosigmoid hypersensitivity reported in both IBS and UC patients. METHODS UC disease activity was quantified using activity index scores. Perception thresholds for discomfort during rectosigmoid distension were compared between 11 UC patients with quiescent or mild disease activity, 18 IBS patients, and 13 healthy controls. RESULTS Although UC activity index scores negatively correlated with perceptual thresholds for discomfort (r=-0.76, p=0.016), UC patients had higher discomfort thresholds compared with IBS patients and controls before (p=0.02) and after (p<0.001) a noxious sigmoid conditioning stimulus. CONCLUSIONS Rectal perception was attenuated in UC but enhanced in IBS. In chronic mild inflammation, activation of antinociceptive mechanisms may prevent the development of visceral hyperalgesia. Low grade mucosal inflammation alone is unlikely to be responsible for symptoms in functional gastrointestinal disorders.
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Affiliation(s)
- L Chang
- UCLA/CURE Neuroenteric Disease Program, Department of Medicine and Physiology, UCLA School of Medicine, Los Angeles, California 90073, USA.
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Flechtner-Mors M, Ditschuneit HH, Johnson TD, Suchard MA, Adler G. Metabolic and weight loss effects of long-term dietary intervention in obese patients: four-year results. Obes Res 2000; 8:399-402. [PMID: 10968732 DOI: 10.1038/oby.2000.48] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To investigate the contribution of meal and snack replacements for long-term weight maintenance and risk factor reduction in obese patients. RESEARCH METHODS AND PROCEDURES Prospective, randomized, two-arm, parallel intervention for 12 weeks followed by a prospective single-arm 4-year trial in a University Hospital clinic. One hundred patients, >18 years old and with a body mass index > 25 and < or = 40 kg/m2, were prescribed a 1,200 to 1,500 kcal/d control diet (Group A) or an isoenergetic diet, including two meal and snack replacements (vitamin- and mineral-fortified shakes, soups, and bars) and one meal high in fruits and vegetables (Group B). Following a 3 months of weight loss, all patients were prescribed the same energy-restricted diet (1,200 to 1,500 kcal) with one meal and one snack replacement for an additional 4 years. RESULTS All 100 patients were evaluated at 12 weeks. Mean percentage weight loss was 1.5 +/- 0.4% and 7.8 +/- 0.5% (mean +/- SEM) for Groups A and B, respectively. At 12 weeks systolic blood pressure, plasma triacylglycerol, glucose, and insulin concentrations were significantly reduced in Group B, whereas no changes occurred in Group A. After 4 years, 75% of the patients were evaluated. Total mean weight loss was 3.2 +/- 0.8% for Group A and 8.4 +/- 0.8% (mean +/- SEM) for Group B. Both groups showed significant improvement in blood glucose and insulin (p < 0.001), but only Group B showed significant improvement in triacylglycerol and systolic blood pressure compared to baseline values (p < 0.001). DISCUSSION Providing a structured meal plan via vitamin- and mineral-fortified liquid meal replacements is a safe and effective dietary strategy for obese patients. Long-term maintenance of weight loss with meal replacements can improve certain biomarkers of disease risk.
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Abstract
The effects of stimulating P2Y1 or P2Y2 purinoceptors on the endothelium of isolated middle cerebral arteries (MCAs), third-order branches of the MCA (bMCAs), and penetrating arterioles (PAs) of the rat were studied. After pressurization and development of spontaneous tone (25% contraction), resting diameters for MCAs, bMCAs, and PAs were 203 +/- 5 (n = 50), 99 +/- 2 (n = 42), and 87 +/- 2 micron (n = 53), respectively. Luminal application of the P2Y1-selective agonist 2-methylthioadenosine 5'-triphosphate elicited dose-dependent dilations (or loss of intrinsic tone) in MCAs but not in bMCAs or PAs. The dilation in MCAs was completely blocked by removal of the endothelium or by nitro-L-arginine methyl ester (10(-5) M), an inhibitor of NO synthase. Luminal application of the P2Y2-selective agonist ATP elicited dilations in MCAs, bMCAs, and PAs. Removal of the endothelium abolished the dilations in all vessel groups. Dilations in MCAs have been shown to involve both NO and endothelium-derived hyperpolarizing factor (EDHF). The dilations in bMCAs and PAs had a minor NO component and prominent EDHF component; that is, 1) the dilations to ATP were not diminished by the combined inhibition of NO synthase and cyclooxygenase, 2) the dilations were accompanied by significant hyperpolarizations of the vascular smooth muscle (approximately 15 mV), and 3) the dilations were completely abolished by the calcium-activated potassium channel blocker charybdotoxin. We concluded that the role of NO in purinoceptor-induced dilations diminishes along the cerebrovascular tree in the rat, whereas the role of EDHF becomes more prominent.
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Affiliation(s)
- J You
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030, USA
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16
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O'Day SJ, Gammon G, Boasberg PD, Martin MA, Kristedja TS, Guo M, Stern S, Edwards S, Fournier P, Weisberg M, Cannon M, Fawzy NW, Johnson TD, Essner R, Foshag LJ, Morton DL. Advantages of concurrent biochemotherapy modified by decrescendo interleukin-2, granulocyte colony-stimulating factor, and tamoxifen for patients with metastatic melanoma. J Clin Oncol 1999; 17:2752-61. [PMID: 10561350 DOI: 10.1200/jco.1999.17.9.2752] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [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: 11/20/2022] Open
Abstract
PURPOSE Concurrent biochemotherapy results in high response rates but also significant toxicity in patients with metastatic melanoma. We attempted to improve its efficacy and decrease its toxicity by using decrescendo dosing of interleukin-2 (IL-2), posttreatment granulocyte colony-stimulating factor (G-CSF), and low-dose tamoxifen. PATIENTS AND METHODS Forty-five patients with poor prognosis metastatic melanoma were treated at a community hospital inpatient oncology unit affiliated with the John Wayne Cancer Institute (Santa Monica, CA) between July 1995 and September 1997. A 5-day modified concurrent biochemotherapy regimen of dacarbazine, vinblastine, cisplatin, decrescendo IL-2, interferon alfa-2b, and tamoxifen was repeated at 21-day intervals. G-CSF was administered beginning on day 6 for 7 to 10 days. RESULTS The overall response rate was 57% (95% confidence interval, 42% to 72%), the complete response rate was 23%, and the partial response rate was 34%. Complete remissions were achieved in an additional 11% of patients by surgical resection of residual disease after biochemotherapy. The median time to progression was 6.3 months and the median duration of survival was 11.4 months. At a maximum follow-up of 36 months (range, 10 to 36 months), 32% of patients are alive and 14% remain free of disease. Decrescendo IL-2 dosing and administration of G-CSF seemed to reduce toxicity, length of hospital stay, and readmission rates. No patient required intensive care unit monitoring, and there were no treatment-related deaths. CONCLUSION The data from this study indicate that the modified concurrent biochemotherapy regimen reduces the toxicity of concurrent biochemotherapy with no apparent decrease in response rate in patients with poor prognosis metastatic melanoma.
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Affiliation(s)
- S J O'Day
- Division of Medical and Surgical Oncology, John Wayne Cancer Institute at Saint John's Health Center, Santa Monica, CA 90404, USA. o'
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17
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You J, Johnson TD, Marrelli SP, Mombouli JV, Bryan RM. P2u receptor-mediated release of endothelium-derived relaxing factor/nitric oxide and endothelium-derived hyperpolarizing factor from cerebrovascular endothelium in rats. Stroke 1999; 30:1125-33. [PMID: 10229754 DOI: 10.1161/01.str.30.5.1125] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [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: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Stimulation of P2u purinoceptors by UTP on endothelium dilates the rat middle cerebral artery (MCA) through the release of endothelium-derived relaxing factor/nitric oxide (EDRF/NO) and an unknown relaxing factor. The purpose of this study was to determine whether this unknown relaxing factor is endothelium-derived hyperpolarizing factor (EDHF). METHODS Rat MCAs were isolated, cannulated, pressurized, and luminally perfused. UTP was added to the luminal perfusate to elicit dilations. RESULTS Resting outside diameter of the MCAs in one study was 209+/-7 micrometer (n=10). The MCAs showed concentration-dependent dilations with UTP administration. Inhibition of NO synthase with NG-nitro-L-arginine methyl ester (L-NAME) (1 micromol/L to 1 mmol/L) did not diminish the maximum response to UTP but did shift the concentration-response curve to the right. Scavenging NO with hemoglobin (1 or 10 micromol/L) or inhibition of guanylate cyclase with ODQ (1 or 10 micromol/L) had effects on the UTP-mediated dilations similar to those of L-NAME. In the presence of L-NAME, dilations induced by 10 micromol/L UTP were accompanied by 13+/-2 mV (P<0.009) hyperpolarization of the vascular smooth muscle membrane potential (-28+/-2 to -41+/-1 mV). Iberiotoxin (100 nmol/L), blocker of the large-conductance calcium-activated K channels, sometimes blocked the dilation, but its effects were variable. Charybdotoxin (100 nmol/L), also a blocker of the large-conductance calcium-activated K channels, abolished the L-NAME-insensitive component of the dilation to UTP. CONCLUSIONS Stimulation of P2u purinoceptors on the endothelium of the rat MCA released EDHF, in addition to EDRF/NO, and dilated the rat MCA by opening an atypical calcium-activated K channel.
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MESH Headings
- 4-Aminopyridine/pharmacology
- Animals
- Apamin/pharmacology
- Barium Compounds/pharmacology
- Cerebral Arteries/metabolism
- Cerebrovascular Circulation/physiology
- Charybdotoxin/pharmacology
- Chlorides/pharmacology
- Endothelium, Vascular/chemistry
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Enzyme Inhibitors/pharmacology
- Glyburide/pharmacology
- Hypoglycemic Agents/pharmacology
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide/metabolism
- Oxadiazoles/pharmacology
- Peptides/pharmacology
- Potassium Channels/metabolism
- Potassium Chloride/pharmacology
- Quinoxalines/pharmacology
- Rats
- Rats, Long-Evans
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2Y2
- Tetraethylammonium/pharmacology
- Uridine Triphosphate/pharmacology
- Vasodilation/drug effects
- Vasodilation/physiology
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Affiliation(s)
- J You
- Department of Anesthesiology, Graduate Program in Cardiovascular Sciences of the DeBakey Heart Center, Baylor College of Medicine, Houston, Texas, USA
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Giorgi JV, Hultin LE, McKeating JA, Johnson TD, Owens B, Jacobson LP, Shih R, Lewis J, Wiley DJ, Phair JP, Wolinsky SM, Detels R. Shorter survival in advanced human immunodeficiency virus type 1 infection is more closely associated with T lymphocyte activation than with plasma virus burden or virus chemokine coreceptor usage. J Infect Dis 1999; 179:859-70. [PMID: 10068581 DOI: 10.1086/314660] [Citation(s) in RCA: 834] [Impact Index Per Article: 33.4] [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: 12/16/2022] Open
Abstract
To define predictors of survival time in late human immunodeficiency virus type 1 (HIV-1) disease, long- and short-duration survivors were studied after their CD4+ T cells fell to </=50/mm3. Immune activation of CD4+ and CD8+ T cells, as measured by elevated cell surface expression of CD38 antigen, was strongly associated with shorter subsequent survival (P</=.002). The naive CD45RA+CD62L+ T cell reserve was low in all subjects and did not predict survival (P=.34 for CD4+ and.08 for CD8+ cells). Higher virus burden correlated with CD8+ but not CD4+ cell activation and, after correcting for multiple comparisons, was not associated with shorter survival (P=.02). All of the patients' viruses used CCR5, CXCR4, or both, and coreceptor usage did not predict survival (P=. 27). Through mechanisms apparently unrelated to higher virus burden, immune activation is a major determinant of survival in advanced HIV-1 disease.
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Affiliation(s)
- J V Giorgi
- The Multicenter AIDS Cohort Study: Department of Medicine, University of California, Los Angeles, CA, 90095-1745, USA. . edu
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Ditschuneit HH, Flechtner-Mors M, Johnson TD, Adler G. Metabolic and weight-loss effects of a long-term dietary intervention in obese patients. Am J Clin Nutr 1999; 69:198-204. [PMID: 9989680 DOI: 10.1093/ajcn/69.2.198] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.4] [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: 11/14/2022] Open
Abstract
BACKGROUND Obesity is a chronic disease that has become one of the most serious health problems in Western society. OBJECTIVE We assessed the long-term effects of an energy-restricted diet combined with 1 or 2 daily meal replacements on body weight and biomarkers of disease risk in 100 obese patients. DESIGN Phase 1 consisted of a 3-mo, prospective, randomized, parallel intervention study of 2 dietary interventions to reduce weight. The energy-restricted diet (5.2-6.3 MJ/d) consisted of conventional foods (group A) or an isoenergetic diet with 2 meals and 2 snacks replaced daily by energy-controlled, vitamin-and-mineral-supplemented prepared foods (group B). Phase 2 consisted of a 24-mo, case-control, weight-maintenance study with an energy-restricted diet and 1 meal and 1 snack replaced daily for all patients. RESULTS Total weight loss (as a percentage of initial body weight) was 5.9+/-5.0% in group A and 11.3+/-6.8% in group B (P < 0.0001). During phase 1, mean weight loss in group B (n = 50) was 7.1+/-3.5 kg, with significant reductions in plasma triacylglycerol, glucose, and insulin concentrations (P < 0.0001). Group A patients (n = 50) lost an average of 1.3+/-2.2 kg with no significant improvements in these biomarkers. During phase 2, both groups lost on average an additional 0.07% of their initial body weight every month (P < 0.01). During the 27-mo study, both groups experienced significant reductions in systolic blood pressure and plasma concentrations of triacylglycerol, glucose, and insulin (P < 0.01). CONCLUSION These findings support the hypothesis that defined meal replacements can be used for successful, long-term weight control and improvements in certain biomarkers of disease risk.
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Affiliation(s)
- H H Ditschuneit
- University Hospital, Department of Medicine, University Ulm, Germany.
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20
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Takahashi T, Johnson TD, Nishinaka Y, Morton DL, Irie RF. IgM anti-ganglioside antibodies induced by melanoma cell vaccine correlate with survival of melanoma patients. J Invest Dermatol 1999; 112:205-9. [PMID: 9989797 DOI: 10.1046/j.1523-1747.1999.00493.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [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: 11/20/2022]
Abstract
Melanoma cells express ganglioside antigens GM3, GD3, GM2, and GD2 on their surface. This study examined whether immunization with a melanoma cell vaccine induced anti-ganglioside antibody responses in melanoma patients and whether these responses were correlated with survival. Sixty-six patients who had received melanoma cell vaccine immunotherapy after surgical removal of regional metastatic melanoma were identified. Cryopreserved serum samples from these patients were used in an enzyme-linked immunsorbent assay to determine the IgM antibody levels to GM2, GD2, GM3, and GD3 prior to melanoma cell vaccine treatment and 4 wk after the first melanoma cell vaccine immunization. All antibody levels significantly increased by week 4 (p < 0.001 for all four antibodies) and all increases were significantly associated with survival (anti-GD2, p < 0.001; anti-GM2, p = 0.001; anti-GD3, p < 0.001; anti-GM3, p < 0.001). Anti-tumor activity of these antibodies was proved using five representative antibody-positive sera in a complement-dependent cytotoxicity assay with cultured melanoma cell lines. These studies suggest that GM2, GD2, GM2, and GD3 expressed by melanoma cells can induce specific IgM antibodies and that high levels of these antibodies might have a beneficial impact on survival.
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Affiliation(s)
- T Takahashi
- Department of Biotechnology Sciences, John Wayne Cancer Institute, Santa Monica, California 90404, USA
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Kimme-Smith C, Davis DL, McNitt-Gray M, Goldin J, Hart E, Batra P, Johnson TD. Computed radiography dual energy subtraction: performance evaluation when detecting low-contrast lung nodules in an anthropomorphic phantom. J Digit Imaging 1999; 12:29-33. [PMID: 10036665 PMCID: PMC3452434 DOI: 10.1007/bf03168624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A dedicated chest computed radiography (CR) system has an option of energy subtraction (ES) acquisition. Two imaging plates, rather than one, are separated by a copper filter to give a high-energy and low-energy image. This study compares the diagnostic accuracy of conventional computed radiography to that of ES obtained with two radiographic techniques. One soft tissue only image was obtained at the conventional CR technique (s = 254) and the second was obtained at twice the radiation exposure (s = 131) to reduce noise. An anthropomorphic phantom with superimposed low-contrast lung nodules was imaged 53 times for each radiographic technique. Fifteen images had no nodules; 38 images had a total of 90 nodules placed on the phantom. Three chest radiologists read the three sets of images in a receiver operating characteristic (ROC) study. Significant differences in Az were only found between (1) the higher exposure energy subtracted images and the conventional dose energy subtracted images (P = .095, 90% confidence), and (2) the conventional CR and the energy subtracted image obtained at the same technique (P = .024, 98% confidence). As a result of this study, energy subtracted images cannot be substituted for conventional CR images when detecting low-contrast nodules, even when twice the exposure is used to obtain them.
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Affiliation(s)
- C Kimme-Smith
- UCLA School of Medicine, Department of Radiological Sciences 90095-1721, USA
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22
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Brown JP, Hosking DJ, Ste-Marie L, Johnston CC, Reginster J, Ryan WG, Johnson TD, Bekker PJ. Risedronate, a highly effective, short-term oral treatment for Paget's disease: a dose-response study. Calcif Tissue Int 1999; 64:93-9. [PMID: 9914313 DOI: 10.1007/s002239900584] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Risedronate is a potent pyridinyl bisphosphonate being developed for bone diseases such as Paget's disease and osteoporosis. In this study, we compared the efficacy, safety, and tolerability of three different doses of oral risedronate in 62 patients with severe Paget's disease of bone [serum alkaline phosphatase (AP) >3 times the upper limit of normal]. Patients were treated at six study centers with either 10, 20, or 30 mg oral risedronate daily for 28 days and followed up to day 85. The primary efficacy parameter was percentage change from baseline in AP excess. The data show that there is a dose-response with risedronate: patients who received 30 mg oral risedronate for 28 days benefited most, with a mean percentage decrease in AP excess of 72.2% (20 mg: 57.9%; 10 mg: 48. 0%). Time to response-the first time point when there was a >/=30% reduction from baseline in AP excess and >/=50% reduction from baseline in urinary hydroxyproline (HP)/creatinine-was also significantly shorter (median 29 days) in the 30 mg group compared with the other two groups (20 mg: 43 days and 10 mg: 71 days). Long-term follow-up data up to 33 months from the start of the study indicated that AP remained below baseline levels for all patients. Histologic evaluation of bone formed during risedronate therapy demonstrated that normal lamellar bone was formed as opposed to woven pagetic bone, with no evidence of osteomalacia. Risedronate was well tolerated. Transient decreases in serum calcium and increases in serum intact parathyroid hormone were observed, consistent with the pharmacology of risedronate. In conclusion, risedronate administered at daily doses of 10, 20, and 30 mg for 28 days was effective in reducing the biochemical indices of disease activity in patients with severe Paget's disease of bone. A daily dose of 30 mg was most effective without compromising safety or tolerability.
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Affiliation(s)
- J P Brown
- Le Centre hospitalier universitaire de Québec, Pavillon CHUL, S-782, 2705 boul. Laurier, Ste-Foy, Québec, Canada, G1V 4G2
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23
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Marrelli SP, Khorovets A, Johnson TD, Childres WF, Bryan RM. P2 purinoceptor-mediated dilations in the rat middle cerebral artery after ischemia-reperfusion. Am J Physiol 1999; 276:H33-41. [PMID: 9887014 DOI: 10.1152/ajpheart.1999.276.1.h33] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelial-mediated dilations to selective P2Y1 and P2Y2 purinoceptor agonists [2-methylthioadenosine triphosphate (2MeS-ATP) and uridine 5'-triphosphate (UTP), respectively] were evaluated in middle cerebral arteries (MCAs) of rats after 2 h of ischemia followed by 24 h of reperfusion (I/R). MCAs were harvested, pressurized to 85 mmHg, and luminally perfused. 2MeS-ATP, which dilates by the synthesis and release of nitric oxide (NO), had significantly reduced maximum dilations following I/R. Reduced smooth muscle sensitivity to NO may explain the reduced dilation to 2MeS-ATP. In contrast, the dilations elicited by UTP were potentiated in that the concentration of agonist necessary to produce one-half of the maximum dilation was reduced by 75%. The potentiated dilation to UTP was the result of an endothelial factor having all the characteristics of the endothelium-derived hyperpolarizing factor (EDHF). That is, it was neither NO nor a cyclooxygenase metabolite, and its actions involved calcium-activated potassium channels and smooth muscle hyperpolarization. We conclude that the effect of I/R on endothelial-mediated dilations depends on the receptor system and the mechanism of dilation. Dilations elicited by 2MeS-ATP were attenuated, while dilations UTP were potentiated due to the upregulation of the EDHF mechanism.
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Affiliation(s)
- S P Marrelli
- The Graduate Program in Cardiovascular Sciences of the DeBakey Heart Center, Baylor College of Medicine, Houston, Texas 77030, USA
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24
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Giorgi JV, Majchrowicz MA, Johnson TD, Hultin P, Matud J, Detels R. Immunologic effects of combined protease inhibitor and reverse transcriptase inhibitor therapy in previously treated chronic HIV-1 infection. AIDS 1998; 12:1833-44. [PMID: 9792384 DOI: 10.1097/00002030-199814000-00015] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [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: 10/27/2022]
Abstract
OBJECTIVE To evaluate the efficacy of combination protease and reverse transcriptase inhibitor therapy in correcting HIV-1-induced lymphocyte subset abnormalities in previously treated adults. DESIGN A 48-week observational study of lymphocyte subsets in 12 participants in the Multicenter AIDS Cohort Study who were already taking at least one reverse transcriptase inhibitor and added a protease inhibitor to their treatment regimen. Comparison groups were HIV-seronegative homosexual men, HIV-seronegative heterosexual men, and homosexual HIV-1-infected men who were long-term non-progressors. METHODS Three-color immunofluorescence and monoclonal antibodies were used to assess HIV-1-induced lymphocyte subset alterations related to immune deficiency and immune activation. Plasma HIV-1 RNA levels were monitored to assess suppression of viral replication. RESULTS CD4+ cell counts significantly increased and lymphocyte activation measured as CD38 and HLA-DR expression on CD8+ T cells significantly decreased by 48 weeks. CD4+ cell values remained abnormal even in those who were fully suppressed. Some T-cell activation markers decreased to levels observed in long-term non-progressors. The increase in CD4+ T-cell numbers reached a plateau by week 24, but the increase in resting HLA-DR- CD38-T cells was sustained through week 48. Proportions of CD45RA+ CD62L-selectin+ and CD28+ CD4+ T-cell subsets and Fas expression were not abnormal at baseline compared with seronegative homosexual controls. CONCLUSIONS The most significant impact of suppression of viral replication was reversal of T-cell activation. However, normalization of lymphocyte subset perturbations associated with chronic HIV-1 infection was not achieved after 1 year of treatment with current combination antiretroviral regimens. More profound viral suppression, therapy for longer than 1 year, or immunologic augmentation may be needed to fully reverse the abnormalities.
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Affiliation(s)
- J V Giorgi
- Multicenter AIDS Cohort Study and University of California Los Angeles School of Medicine, 90095-1745, USA
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25
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Goldin JG, McNitt-Gray MF, Sorenson SM, Johnson TD, Dauphinee B, Kleerup EC, Tashkin DP, Aberle DR. Airway hyperreactivity: assessment with helical thin-section CT. Radiology 1998; 208:321-9. [PMID: 9680554 DOI: 10.1148/radiology.208.2.9680554] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [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: 11/11/2022]
Abstract
PURPOSE To determine the accuracy of helical computed tomography (CT) for assessing reversible changes in bronchial size and air trapping due to airway hyperreactivity. MATERIALS AND METHODS Spirometry and helical CT were performed in 15 patients with mild asthma and six healthy control subjects before and after bronchial provocation with methacholine chloride and after reversal of provocation with albuterol. CT was performed at suspended functional residual capacity and at residual volume in two lung regions (above and below the carina). Bronchial area and lung attenuation measurements were compared. RESULTS At baseline, lung attenuation frequency distribution curves were similar between the control and asthma groups. After methacholine, control subjects showed a decrease of less than 10% in the forced expiratory volume at 1 second (FEV1) and no significant differences in lung attenuation curves. Patients with asthma showed a 20%-36% decrease in FEV1, with significant decreases in the median and lowest 10th percentile regions of the attenuation curves and in the cross-sectional area of small (< 5-mm2) airways (P < .001 for all comparisons). After albuterol, control subjects showed no change in spirometric measurements, lung attenuation, or bronchial size, whereas all such parameters returned to baseline levels in patients with asthma. CONCLUSION Functional helical CT can accurately demonstrate reversible airflow obstruction resulting from airway hyperreactivity.
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Affiliation(s)
- J G Goldin
- Dept of Radiological Sciences, UCLA School of Medicine 90095-1721, USA
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Abstract
It has been well established that alterations in polyamine metabolism are associated with animal models of global ischemia. Recently, this has been extended to include models of focal ischemia and traumatic brain injury. There is much evidence to support the idea that polyamines may play a multifaceted detrimental role following ischemia reperfusion. Due to the deficit of knowledge about their physiology in the CNS, the link between ischemia-induced alterations in polyamine metabolism and neuronal injury remains to be substantiated. With the recent revelation that polyamines are major intracellular modulators of inward rectifier potassium channels and certain types of NMDA and AMPA receptors, the long wait for the physiologic relevance of these ubiquitous compounds may be in sight. Therefore, it is now conceivable that the alterations in polyamines could have major effects on ion homeostasis in the CNS, especially potassium, and thus account for the observed injury after cerebral ischemia.
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Affiliation(s)
- T D Johnson
- Department of Anesthesiology, Baylor College of Medicine, Houston, TX, USA
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Marrelli SP, Johnson TD, Khorovets A, Childres WF, Bryan RM. Altered function of inward rectifier potassium channels in cerebrovascular smooth muscle after ischemia/reperfusion. Stroke 1998; 29:1469-74. [PMID: 9660405 DOI: 10.1161/01.str.29.7.1469] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [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: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Several recent studies have demonstrated that inward rectifier potassium channels (K(ir)s) are located on vascular smooth muscle of cerebral arteries in the rat. Activation of the K(ir)s dilates the arteries by relaxing the vascular smooth muscle. We tested the following hypothesis in the present study: function of inward rectifier potassium channels is altered after ischemia/reperfusion (I/R). METHODS Temporary (2-hour) focal ischemia was induced in male Long-Evans rats (3% isoflurane anesthesia) by the intraluminal filament model. After 24 hours of reperfusion, ipsilateral and contralateral middle cerebral arteries (MCAs) were harvested and mounted on micropipettes, pressurized to 85 mm Hg, and luminally perfused. RESULTS Resting diameters for contralateral (control) and ipsilateral (I/R) MCAs were not significantly different (215+/-4 microm and 211+/-5 microm [n = 6 and n = 7], respectively). Activation of the K(ir)s by abluminal administration of 15 mmol/L KCl to the control MCAs dilated the MCA by 34+/-4% (n = 8). Activation of the K(ir)s in I/R MCAs produced a dilation of only 11+/-3% (n = 8; P<0.001 compared with control). BaCl2 (75 micromol/L), a concentration-selective inhibitor of the K(ir)s, significantly attenuated the dilation produced by 15 mmol/L KCl in control MCAs but not in the I/R MCAs. Endothelial-mediated dilations elicited by the luminal administration of uridine triphosphate (10 micromol/L) produced similar dilations in both groups (32+/-5% for sham [n = 4] and 33+/-2% for I/R [n = 4]), indicating that dilator function in general was not altered in I/R vessels. CONCLUSIONS We conclude that Kir function is altered after I/R. The Kir altered function is likely to exacerbate the brain injury occurring after I/R.
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Affiliation(s)
- S P Marrelli
- Department of Anesthesiology, Baylor College of Medicine, Houston, Tex 77030, USA
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Abstract
We studied the effect of nitrous oxide (N2O) diffusion on size 2 LMA cuff inflation in 52 children, 38 +/- 21 months of age. LMA cuffs were inflated with air (Group A) or 65% N2O, oxygen and halothane (Group B). Cuffs were inflated in a stepwise manner, achieving a cuff leak pressure of 17 +/- 4 cm H2O for all patients. Cuff volume and intracuff pressure increased in Group A (8.5 +/- 1.0 ml to 10.8 +/- 1.4 ml and 101 +/- 36 mmHg to 152 +/- 42 mmHg, respectively) and decreased in Group B (8.9 +/- 1.0 ml to 6.6 +/- 1.5 ml and 90 +/- 30 mmHg to 53 +/- 37 mmHg, respectively). Cuff leak pressure did not change significantly in either group. We conclude that cuff inflation with a mixture of N2O/oxygen prevents N2O diffusion into the cuff, avoiding cuff overinflation without compromising LMA function.
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Affiliation(s)
- J T Algren
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas, USA
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Abstract
Inward rectifier K+ channels (Kirs) were studied in the isolated perfused rat middle cerebral artery (MCA). The addition of 15 mM K+ (KCl) to the extraluminal bath dilated the MCAs. These dilations were blocked by selective inhibitors for the Kirs (40 microM BaCl2 or 40 mM CsCl) but not selective inhibitors for other K+ channels (glibenclamide, tetraethylammonium, or 4-aminopyridine). Neither removal of the endothelium nor treatment with the nitric oxide synthase inhibitor (NG-nitro-L-arginine methyl ester, 10 microM) affected the K(+)-induced dilation. The addition of BaCl2 to resting MCAs produced a dose-dependent constriction of 8-12%, indicating that, during resting conditions, Kirs aid in setting or determining the resting tone. The magnitude of the dilations produced by the addition of K+ or constrictions produced by BaCl2 were independent of pressure over a range of 40-100 mmHg. We conclude that Kirs, which produce a dilation when activated, exist on the vascular smooth muscle of the rat MCA. These Kirs aid in determining the resting tone of the vessel, and their function is independent of pressure over physiological pressure ranges.
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Affiliation(s)
- T D Johnson
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030, USA
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McNitt-Gray MF, Goldin JG, Johnson TD, Tashkin DP, Aberle DR. Development and testing of image-processing methods for the quantitative assessment of airway hyperresponsiveness from high-resolution CT images. J Comput Assist Tomogr 1997; 21:939-47. [PMID: 9386287 DOI: 10.1097/00004728-199711000-00017] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [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: 02/05/2023]
Abstract
PURPOSE Our goal was to develop a protocol and image-processing methods to quantitate both bronchial and lung attenuation changes in patients imaged with helical high-resolution CT (HRCT). METHOD Human subjects underwent helical HRCT at two suspended breath-hold conditions, functional residual capacity and residual volume, at baseline and following methacholine-induced bronchoprovocation. A semiautomated contouring program was used to define anatomically like bronchi and axial lung sections from the different physiologic sequences, from which automated measurements of area, shape, and attenuation were made. Because the gray level threshold for contouring directly affects the measured area of an anatomic structure, two types of evaluation studies were performed. These included in vivo measurements using baseline parameters of human subjects as the standard of reference and in vitro measurements of a CT phantom designed to simulate the air-soft tissue interfaces of bronchi. RESULTS Phantom tests showed that the minimum difference between actual and measured areas of holes occurred at a threshold of -500 HU. The smallest diameter holes were most sensitive to changes in threshold value. However, although absolute area measurements of both simulated and human bronchi varied with threshold level, the percent changes in airway areas between baseline and bronchoprovocation sequences were relatively stable at any given threshold. CONCLUSION These image-processing tools provide reproducible measurements of area as well as attenuation characteristics of pulmonary structures and may offer insights into the practical use of functional imaging in evaluating conditions of airflow obstruction.
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Affiliation(s)
- M F McNitt-Gray
- Department of Radiological Sciences, University of California Los Angeles School of Medicine 90095-1721, USA
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31
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Abstract
The hypothesis that ATP and ADP produce dilations of rat middle cerebral arteries (MCAs) by different mechanisms was tested. Vessel diameters were measured from pressurized, perfused MCAs after application of different agonists. The luminal administration of ATP and ADP elicited concentration-dependent dilations (35% maximum). Removal of endothelium abolished the dilation to intraluminal ATP and attenuated the dilation to intraluminal ADP. The dilations to ATP were abolished with N omega-nitro-L-arginine methyl ester (L-NAME; 10 microM), a nitric oxide synthase inhibitor, at ATP concentrations of 1 microM and below. However, at concentrations of 10 microM ATP and above, L-NAME had no effect on the response. The dilations to ADP were attenuated by L-NAME to the same degree as removal of endothelium. The mechanism for dilation by ATP was identical to that of UTP, a selective P2u purinoceptor agonist. The mechanism of dilation by ADP was similar to that of 2-methylthioadenosine 5'-triphosphate, a selective P2y purinoceptor agonist. We conclude that ATP and ADP elicit dilations of rat MCA by different mechanisms. ATP and ADP likely stimulate P2u and P2y purinoceptors, respectively.
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Affiliation(s)
- J You
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030, USA
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Kaye RA, Döring J, Holcomb JW, Johns GD, Johnson TD, Riley MA, Sylvan GN, Womble PC, Wood VA, Tabor SL, Saladin JX. Transition strengths and new band structures in odd-odd 78Rb. Phys Rev C Nucl Phys 1996; 54:1038-1056. [PMID: 9971438 DOI: 10.1103/physrevc.54.1038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Kimme-Smith C, Hart EM, Goldin JG, Johnson TD, Terwilliger R, Aberle DR. Detection of simulated lung nodules with computed radiography: effects of nodule size, local optical density, global object thickness, and exposure. Acad Radiol 1996; 3:735-41. [PMID: 8883514 DOI: 10.1016/s1076-6332(96)80412-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [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: 02/02/2023]
Abstract
RATIONALE AND OBJECTIVES We quantified differences in the detection of simulated lung nodules on computed radiographs on the basis of variations in nodule size, local contrast, body habitus (global contrast), and exposure. METHODS A step-wedge phantom was developed to simulate the attenuation ranges of the lung, retrocardiac, and subdiaphragmatic regions of the adult human chest. Additional Lucite wedges were used to simulate two different body thicknesses and to provide variable structural noise. Soft-tissue-equivalent nodules of 3-mm and 5-mm diameter that resulted in 10% differences in attenuation from lung equivalence were embedded in lung-equivalent material. By superimposing the sheets in various positions, 84 unique nodule configurations containing eight nodules per image were exposed on a computed radiography system. Computed radiographs were acquired at two different exposures approximating standard exposure and underexposure. For each resulting phantom image, seven observers scored the presence or absence of a nodule within individual cells of a 5 x 5 grid matrix. RESULTS True-positive fractions for 3-mm-diameter nodules were very low across all conditions. True-positive fractions for 5-mm-diameter nodules varied from 0.23 to 0.98. Significant differences in the conspicuity of 5-mm nodules depended on differences in phantom thickness and differences in the locations of nodules within lung-, retrocardiac-, or subdiaphragmatic-equivalent regions. Accuracy in detecting nodules was significantly lower at lower exposures when nodules were located in the subdiaphragmatic-equivalent region. CONCLUSION On computed radiographs, small nodules (5-mm diameter) can be reliably detected when they are located in areas of high or moderate surrounding local contrast, such as the lung or mediastinal regions. Detection of nodules decreases in regions of lower optical density corresponding to the subdiaphragmatic regions of the chest. The decrease in nodule detectability is greatest under conditions that simulate large body thickness and underexposure.
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Affiliation(s)
- C Kimme-Smith
- Department of Radiological Sciences, University of California, Los Angeles School of Medicine 90095-1721, USA
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34
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Abstract
This study was performed to assess the role of exogenously administered polyamines on rat basilar and femoral artery contractile activity in vitro. With the endothelium removed, rings of tissue were set up in organ chambers to measure isometric tension. The polyamines (0.1-3 mM), putrescine, spermidine, and spermine, were added to the tissue baths; after 30 min of incubation a cumulative concentration response curve (CRC) was obtained with either KCl or serotonin (5-HT). Additional CRCs were run with Ca(2+) in high K+ Krebs (60 mM). In both tissues, the CRCs to KCl were shifted to the right in a dose-dependent manner for spermidine and spermine (1 & 3 mM) but not putrescine. Spermine (3 mM) depressed the KCl maxima by 18.6% and 10.1% in the basilar and femoral artery respectively. For 5-HT CRCs, only spermine (3 mM) slightly inhibited the maximal response in both tissues. The most potent action of spermine was on inhibition of Ca(2+) responses in high K+ where the EC50S were shifted 3.5 and 10 fold over control values in the basilar and femoral respectively. We conclude spermidine and spermine, but not putrescine, attenuate vascular smooth muscle contractions on the basilar and femoral arteries in vitro. The exact nature of the inhibition remains to be fully explored, but blockade of calcium entry through voltage operated Ca channels may play a role. Thus, certain polyamines may affect cerebral perfusion by inhibition of vascular contractility.
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Affiliation(s)
- T D Johnson
- Department of Anesthesiology, Baylor College of Medicine, Houston, TX, USA
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35
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Abstract
BACKGROUND Because alpha 2 adrenoceptor agonists are used as adjuncts to anesthetics, their effects on the cerebrovascular circulation are of prime importance. We studied changes in the diameter of rat middle cerebral arteries after stimulation of alpha 2 adrenoceptors with UK14,304. METHODS Rat middle cerebral arteries were isolated, cannulated at each end with a glass micropipette, and pressurized to 85 mmHg. The middle cerebral arteries were immersed in a bath (37 degrees C) containing physiologic saline solution, and luminally perfused with physiologic saline solution (100 microliters/ min). Changes in vessel diameter were measured after magnification with a microscope. RESULTS Resting diameter of the middle cerebral arteries was 239 +/- 13 microns (n = 8) for the first study. A dose-dependent dilation was produced by addition of UK14,304 to the extraluminal bath; a 10-15% increase in diameter occurred at a concentration of 10(-4)M. The dilations produced by UK14,304 were blocked with selective alpha 2-antagonists, idazoxan and rauwolscine, but not by the selective alpha 1-antagonist, prazosin. The dilations could be blocked by removal of the endothelium, or the nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester (10(-5) M). The inhibitory effects of N-nitro-L-arginine methyl ester were reversed with the addition of 10(-3) M L-arginine, but not 10(-3) M D-arginine. Furthermore the dilation produced by UK14,304 was completely abolished with pertussis toxin (100 ng/ml). CONCLUSIONS It was concluded that the stimulation of alpha 2 adrenoceptors with UK14,304 produced a dilation in the rat middle cerebral artery that (1) was dependent on intact endothelium, (2) involved nitric oxide, and (3) acted via a pertussis toxin-sensitive G protein.
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Affiliation(s)
- R M Bryan
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030, USA
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Thiele DL, Kimme-Smith C, Johnson TD, McCombs M, Bassett LW. Using tissue texture surrounding calcification clusters to predict benign vs malignant outcomes. Med Phys 1996; 23:549-55. [PMID: 9157269 DOI: 10.1118/1.597901] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [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: 02/04/2023] Open
Abstract
The positive predictive value of mammography is between 20% and 25% for clustered microcalcifications. For very early cancers there is often a lack of concordance between mammographic signs and pathology. This study examines the usefulness of computer texture analysis to improve the accuracy of malignant diagnosis. Texture analysis of the breast tissue surrounding microcalcifications on digitally acquired images during stereotactic biopsy is used in this study to predict malignant vs benign outcomes. 54 biopsy proven cases (36 benign, 18 malignant) are used. The texture analysis calculates statistical features from gray level co-occurrence matrices and fractal geometry for equal probability and linear quantizations of the image data. Discriminant models are generated using linear discriminant analysis and logistic discriminant analysis. Results do not differ significantly by method of quantization or discriminant analysis. Jackknife results misclassify 2 of 18 malignant cases (sensitivity 89%) and 6 of 36 benign cases (specificity 83%) for logistic discriminant analysis. From this preliminary study, texture analysis appears to show significant discriminatory power between benign and malignant tissue, which may be useful in resolving problems of discordance between pathological and mammographic findings, and may ultimately reduce the number of benign biopsies.
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Affiliation(s)
- D L Thiele
- Department of Physical Sciences, Royal Brisbane Hospital, Herston Qld, Australia
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37
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Rudolph D, Gross CJ, Sheikh JA, Warner DD, Bearden IG, Cunningham RA, Foltescu D, Gelletly W, Hannachi F, Harder A, Johnson TD, Jungclaus A, Kabadiyski MK, Kast D, Lieb KP, Roth HA, Shizuma T, Simpson J, Skeppstedt Ö, Varley BJ, Weiszflog M. Identification of T=0 and T=1 bands in the N=Z=37 nucleus 74Rb. Phys Rev Lett 1996; 76:376-379. [PMID: 10061441 DOI: 10.1103/physrevlett.76.376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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38
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Abstract
Polyamines are found in every cell of the body and the intricate enzymatic reactions responsible for their metabolism and transport in mammalian cells are now well understood. Despite intense efforts, elucidation of the role of polyamines has suffered in that little information of physiological relevance has surfaced. Recently, recombinant receptor techniques and increased availability of polyamine analogues have revealed, as discussed here by David Johnson, modulation of NMDA receptors by polyamines by reversal of tonic proton inhibition, and a function for these compounds as 'intrinsic rectifier factors' for K+ channels.
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Affiliation(s)
- T D Johnson
- Department of Anesthesiology, Houston, Tx 77030, USA
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Bryan RM, Steenberg ML, Eichler MY, Johnson TD, Swafford MW, Suresh MS. Permissive role of NO in alpha 2-adrenoceptor-mediated dilations in rat cerebral arteries. Am J Physiol 1995; 269:H1171-4. [PMID: 7573514 DOI: 10.1152/ajpheart.1995.269.3.h1171] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Dilations produced with UK-14304, a selective alpha 2-adrenoceptor agonist, in rat middle cerebral arteries (MCAs) were blocked after removal of the endothelium or inhibition of nitric oxide synthase (NOS). After endothelium removal or inhibition of NOS, the addition of subthreshold doses of an exogenous nitric oxide (NO) donor, S-nitroso-N-acetylpenicillamine, restored the dilations produced by UK-14304. In a similar manner the guanosine 3',5'-cyclic monophosphate (cGMP) analogues 8-bromoguanosine 3',5'-cyclic monophosphate and N2,2'-O-dibutyrylguanosine 3',5'-cyclic monophosphate restored the dilations of MCAs after endothelial removal. Because NO cannot be synthesized and released in MCAs after inhibition of NOS, it cannot be directly responsible for the dilation. The basal release of NO from the endothelium acts permissively in the vasodilation by maintaining adequate levels of cGMP. Removal of this basal release of NO by removal of endothelium or inhibition of NOS abolishes the alpha 2-adrenoceptor-mediated dilation.
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Affiliation(s)
- R M Bryan
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030, USA
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40
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Jewell JK, Tekyi-Mensah OJ, Cottle PD, Döring J, Green PV, Holcomb JW, Johns GD, Johnson TD, Kemper KW, Kerr PL, Tabor SL, Womble PC, Wood VA. Negative-parity states near the yrast line in 144Nd. Phys Rev C Nucl Phys 1995; 52:1295-1301. [PMID: 9970633 DOI: 10.1103/physrevc.52.1295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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41
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Archer DE, Riley MA, Brown TB, Döring J, Hartley DJ, Johns GD, Johnson TD, Kaye RA, Pfohl J, Tabor SL, Simpson J, Sun Y. Rotational structures in 177Ta. Phys Rev C Nucl Phys 1995; 52:1326-1338. [PMID: 9970637 DOI: 10.1103/physrevc.52.1326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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42
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Döring J, Wood VA, Holcomb JW, Johns GD, Johnson TD, Riley MA, Sylvan GN, Womble PC, Tabor SL. High-spin bands in 80Kr. Phys Rev C Nucl Phys 1995; 52:76-87. [PMID: 9970483 DOI: 10.1103/physrevc.52.76] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Bond RA, Leff P, Johnson TD, Milano CA, Rockman HA, McMinn TR, Apparsundaram S, Hyek MF, Kenakin TP, Allen LF. Physiological effects of inverse agonists in transgenic mice with myocardial overexpression of the beta 2-adrenoceptor. Nature 1995; 374:272-6. [PMID: 7885448 DOI: 10.1038/374272a0] [Citation(s) in RCA: 331] [Impact Index Per Article: 11.4] [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: 01/27/2023]
Abstract
G-protein-coupled receptors are thought to have an inactive conformation (R), requiring an agonist-induced conformational change for receptor/G-protein coupling. But new evidence suggests a two-state model in which receptors are in equilibrium between the inactive conformation (R), and a spontaneously active conformation (R*) that can couple to G protein in the absence of ligand (Fig. 1). Classic agonists have a high affinity for R* and increase the concentration of R*, whereas inverse agonists have a high affinity for R and decrease the concentration of R*. Neutral competitive antagonists have equal affinity for R and R* and do not displace the equilibrium, but can competitively antagonize the effects both of agonists and of inverse agonists. The lack of suitable in vivo model systems has restricted the evidence for the existence of inverse agonists to computer simulations and in vitro systems. We have used a transgenic mouse model in which there is such marked myocardial overexpression of beta 2-adrenoceptors that a significant population of spontaneously activated receptor (R*) is present, inducing a maximal response without agonist. We show that the beta 2-adrenoceptor ligand ICI-118,551 functions as an inverse agonist, providing evidence supporting the existence of inverse agonists and validating the two-state model of G-protein-coupled receptor activation.
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Affiliation(s)
- R A Bond
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Texas 77204
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Milano CA, Allen LF, Dolber PC, Johnson TD, Rockman HA, Bond RA, Lefkowitz RJ. Marked enhancement in myocardial function resulting from overexpression of a human beta-adrenergic receptor gene. J Thorac Cardiovasc Surg 1995; 109:236-41. [PMID: 7853876 DOI: 10.1016/s0022-5223(95)70384-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Transgenic mice with intense cardiac expression of a human beta-adrenergic receptor gene were engineered and shown to display marked improvements in baseline myocardial and left ventricular function. Heart/body weight ratios and histologic appearance were not found to be significantly altered, suggesting that receptor gene expression did not induce pathologic changes. Given the substantial reduction in beta-adrenergic receptor density and resultant reduction in inotropic responsiveness observed in chronic heart failure, these findings represent a novel approach for increasing myocardial function with important clinical implications.
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Affiliation(s)
- C A Milano
- Department of Surgery, Duke University Medical Center, Durham, N.C. 27710
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Johns GD, Döring J, Holcomb JW, Johnson TD, Riley MA, Sylvan GN, Womble PC, Wood VA, Tabor SL. Shape changes in 79Kr. Phys Rev C Nucl Phys 1994; 50:2786-2793. [PMID: 9969976 DOI: 10.1103/physrevc.50.2786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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46
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Tekyi-Mensah OJ, Cottle PD, Döring J, Green PV, Holcomb JW, Johns GD, Johnson JL, Johnson TD, Kemper KW, Kerr PL, Tabor SL, Womble PC, Wood VA. Weak coupling in 143Nd. Phys Rev C Nucl Phys 1994; 50:R1759-R1762. [PMID: 9969911 DOI: 10.1103/physrevc.50.r1759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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47
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Zighelboim RS, Buccino SG, Durham FE, Döring J, Cottle PD, Holcomb JW, Johnson TD, Tabor SL, Womble PC. Negative-parity structures and lifetime measurements in 71As. Phys Rev C Nucl Phys 1994; 50:716-727. [PMID: 9969711 DOI: 10.1103/physrevc.50.716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Döring J, Tabor SL, Holcomb JW, Johnson TD, Riley MA, Womble PC. Onset of collectivity in the odd-odd nucleus 72As. Phys Rev C Nucl Phys 1994; 49:2419-2426. [PMID: 9969489 DOI: 10.1103/physrevc.49.2419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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49
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Milano CA, Allen LF, Rockman HA, Dolber PC, McMinn TR, Chien KR, Johnson TD, Bond RA, Lefkowitz RJ. Enhanced myocardial function in transgenic mice overexpressing the beta 2-adrenergic receptor. Science 1994; 264:582-6. [PMID: 8160017 DOI: 10.1126/science.8160017] [Citation(s) in RCA: 519] [Impact Index Per Article: 17.3] [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: 01/29/2023]
Abstract
Transgenic mice were created with cardiac-specific overexpression of the beta 2-adrenergic receptor. This resulted in increased basal myocardial adenylyl cyclase activity, enhanced atrial contractility, and increased left ventricular function in vivo; these parameters at baseline in the transgenic animals were equal to those observed in control animals maximally stimulated with isoproterenol. These results illustrate a useful approach for studying the effect of gene expression on cardiac contractility. Because chronic heart failure in humans is accompanied by a reduction in the number of myocardial beta-adrenergic receptors and in inotropic responsiveness, these results suggest a potential gene therapy approach to this disease state.
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Affiliation(s)
- C A Milano
- Department of Surgery, Duke University Medical Center, Durham, NC 27710
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50
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Tabor SL, Döring J, Holcomb JW, Johns GD, Johnson TD, Petters TJ, Riley MA, Womble PC. Transition strengths and multiple band structure in 82Sr. Phys Rev C Nucl Phys 1994; 49:730-742. [PMID: 9969279 DOI: 10.1103/physrevc.49.730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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