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Cheran E, Sharmila Rahale C, Divyabharathi P, Viswanathan C, Narayanan L. Corn cob nanocellulose packaging for increasing the shelf life of food products. Int J Biol Macromol 2024; 268:131403. [PMID: 38614176 DOI: 10.1016/j.ijbiomac.2024.131403] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 04/01/2024] [Accepted: 04/03/2024] [Indexed: 04/15/2024]
Abstract
Studies were carried out to develop eco-friendly Packaging material for the extended shelf-life of food products. The current study sought to improve the coated bioactive film's hydrophobicity and antimicrobial properties by preparing active packaging based on biodegradable Poly Lactic Acid (PLA) containing 1 wt% Nanocellulose (NC) and various loadings of essential oil-prepared nanocomposites. Nanocellulose (NC) from Maize Cob was used as filler in the synthesis of nanopolymers enriched with Thyme oil, Cinnamon oil, clove oil, and Rosemary oil. Characterization of nanopolymer-coated bags and their effect on enhancing the shelf-life of food products in different temperature conditions was also studied. The fabricated nanocomposite and nanocellulose were characterized using FTIR, SEM, XRD, Contact angle, TGA, and Tensile mechanical properties. The fabricated nanocomposite-coated paper cum bag shows good hydrophobic properties as well as antimicrobial and insecticidal properties. The results showed that adding essential oils and dispersing nanocellulose to the PLA matrix strengthened its mechanical qualities as well as its efficacy for biodegradation and antimicrobial properties. The current work provides extremely promising materials for future applications in food packaging applications using sustainable nanocomposite-based biodegradable and antimicrobial coated paper cum bags.
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Affiliation(s)
- E Cheran
- Centre For Agricultural Nanotechnology, Directorate of Natural Resource Management, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - C Sharmila Rahale
- Centre For Agricultural Nanotechnology, Directorate of Natural Resource Management, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
| | - P Divyabharathi
- Centre For Agricultural Nanotechnology, Directorate of Natural Resource Management, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - C Viswanathan
- Department of Nano Science & Technology, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - Lakshmi Narayanan
- Department of Nano Science & Technology, Bharathiar University, Coimbatore, Tamil Nadu, India
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Sayed M, Narayanan L, Essa M, Lawrence M, Karsi A, Abdelhamed H. Secreted Extracellular Products of Flavobacterium covae as Potential Immunogenic Factors for Protection against Columnaris Disease in Channel Catfish ( Ictalurus punctatus). Pathogens 2023; 12:808. [PMID: 37375498 DOI: 10.3390/pathogens12060808] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/25/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
Columnaris disease caused by Flavobacterium covae leads to substantial economic losses in commercially important fish species worldwide. The US channel catfish (Ictalurus punctatus) industry is particularly vulnerable to this disease. Therefore, there is an urgent need to develop a vaccine to reduce the economic losses caused by this disease. Secreted extracellular products (SEPs) are considered to be essential bacterial virulence factors that often provide immunogenicity and protection. The current study sought to identify the main SEPs of F. covae and to evaluate their potential to provide protection in channel catfish against columnaris disease. SDS-PAGE analysis of SEPs revealed five protein bands with molecular weights ranging from 13 to 99 kDa. Mass spectrometry analysis showed that these SEPs were hypothetical protein (AWN65_11950), zinc-dependent metalloprotease (AWN65_10205), DNA/RNA endonuclease G (AWN65_02330), outer membrane protein beta-barrel domain (AWN65_12620), and chondroitin-sulfate-ABC endolyase/exolyase (AWN65_08505). Catfish fingerlings were vaccinated with SEPs, SEPs emulsified with mineral oil adjuvant, or heat-inactivated SEPs, or they were sham-immunized through intraperitoneal (IP) injection. After 21 days, an F. covae challenge showed 58.77% and 46.17% survival in the catfish vaccinated with the SEPs and the SEPs emulsified with adjuvant compared to the sham-vaccinated control (100% mortality within 120 h post-infection). However, the heat-inactivated SEPs failed to provide significant protection (23.15% survival). In conclusion, although SEPs contain potentially important immunogenic proteins, further work is needed to optimize their use for long-lasting protection against columnaris disease in fish. These results are significant given the economic impact of columnaris disease on fish farming worldwide.
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Affiliation(s)
- Mohamed Sayed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University,Beni-Suef 62511, Egypt
| | - Lakshmi Narayanan
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Manal Essa
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University,Beni-Suef 62511, Egypt
| | - Mark Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
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Narayanan L, Ozdemir O, Alugubelly N, Ramachandran R, Banes M, Lawrence M, Abdelhamed H. Identification of genetic elements required for Listeria monocytogenes growth under limited nutrient conditions and virulence by a screening of transposon insertion library. Front Microbiol 2022; 13:1007657. [PMID: 36312968 PMCID: PMC9608667 DOI: 10.3389/fmicb.2022.1007657] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 09/22/2022] [Indexed: 01/29/2023] Open
Abstract
Listeria monocytogenes, the causative agent of listeriosis, displays a lifestyle ranging from saprophytes in the soil to pathogenic as a facultative intracellular parasite in host cells. In the current study, a random transposon (Tn) insertion library was constructed in L. monocytogenes strain F2365 and screened to identify genes and pathways affecting in vitro growth and fitness in minimal medium (MM) containing different single carbohydrate as the sole carbon source. About 2,000 Tn-mutants were screened for impaired growth in MM with one of the following carbon sources: glucose, fructose, mannose, mannitol, sucrose, glycerol, and glucose 6-phosphate (G6P). Impaired or abolished growth of L. monocytogenes was observed for twenty-one Tn-mutants with disruptions in genes encoding purine biosynthesis enzymes (purL, purC, purA, and purM), pyrimidine biosynthesis proteins (pyrE and pyrC), ATP synthase (atpI and atpD2), branched-chain fatty acids (BCFA) synthesis enzyme (bkdA1), a putative lipoprotein (LMOF2365_2387 described as LP2387), dUTPase family protein (dUTPase), and two hypothetical proteins. All Tn-mutants, except the atpD2 mutant, grew as efficiently as wild-type strain in a nutrient rich media. The virulence of twenty-one Tn-mutants was assessed in mice at 72 h following intravenous (IV) infection. The most attenuated mutants had Tn insertions in purA, hypothetical protein (LMOf2365_0064 described as HP64), bkdA1, dUTPase, LP2387, and atpD2, confirming the important role of these genes in pathogenesis. Six Tn-mutants were then tested for ability to replicate intracellularly in murine macrophage J774.1 cells. Significant intracellular growth defects were observed in two Tn-mutants with insertions in purA and HP64 genes, suggesting that an intact purine biosynthesis pathway is important for intracellular growth of L. monocytogens. These findings may not be fully generalized to all of L. monocytogenes strains due to their genetic diversity. In conclusion, Tn-mutagenesis identified that biosynthesis of purines, pyrimidines, ATP, and BCFA are important for L. monocytogens pathogenesis. Purine and pyrimidine auxotrophs play an important role in the pathogenicity in other bacterial pathogens, but our study also revealed new proteins essential for both growth in MM and L. monocytogenes strain F2365 virulence.
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Affiliation(s)
- Lakshmi Narayanan
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States,Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Ozan Ozdemir
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Navatha Alugubelly
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Reshma Ramachandran
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States,Department of Poultry Science, Mississippi State University, Mississippi State, MS, United States
| | - Michelle Banes
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Mark Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States,*Correspondence: Hossam Abdelhamed,
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Abdelhamed H, Ramachandran R, Narayanan L, Islam S, Ozan O, Freitag N, Lawrence ML. Role of FruR transcriptional regulator in virulence of Listeria monocytogenes and identification of its regulon. PLoS One 2022; 17:e0274005. [PMID: 36054213 PMCID: PMC9439231 DOI: 10.1371/journal.pone.0274005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022] Open
Abstract
Listeria monocytogenes is a ubiquitous opportunistic foodborne pathogen capable of survival in various adverse environmental conditions. Pathogenesis of L. monocytogenes is tightly controlled by a complex regulatory network of transcriptional regulators that are necessary for survival and adaptations to harsh environmental conditions both inside and outside host cells. Among these regulatory pathways are members of the DeoR-family transcriptional regulators that are known to play a regulatory role in sugar metabolism. In this study, we deciphered the role of FruR, a DeoR family protein, which is a fructose operon transcriptional repressor protein, in L. monocytogenes pathogenesis and growth. Following intravenous (IV) inoculation in mice, a mutant strain with deletion of fruR exhibited a significant reduction in bacterial burden in liver and spleen tissues compared to the parent strain. Further, the ΔfruR strain had a defect in cell-to-cell spread in L2 fibroblast monolayers. Constitutive activation of PrfA, a pleiotropic activator of L. monocytogenes virulence factors, did not restore virulence to the ΔfruR strain, suggesting that the attenuation was not a result of impaired PrfA activation. Transcriptome analysis revealed that FruR functions as a positive regulator for genes encoding enzymes involved in the pentose phosphate pathway (PPP) and as a repressor for genes encoding enzymes in the glycolysis pathway. These results suggested that FruR may function to facilitate NADPH regeneration, which is necessary for full protection from oxidative stress. Interestingly, deletion of fruR increased sensitivity of L. monocytogenes to H2O2, confirming a role for FruR in survival of L. monocytogenes during oxidative stress. Using anti-mouse neutrophil/monocyte monoclonal antibody RB6-8C5 (RB6) in an in vivo infection model, we found that FruR has a specific function in protecting L. monocytogenes from neutrophil/monocyte-mediated killing. Overall, this work clarifies the role of FruR in controlling L. monocytogenes carbon flow between glycolysis and PPP for NADPH homeostasis, which provides a new mechanism allowing metabolic adaptation of L. monocytogenes to oxidative stress.
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Affiliation(s)
- Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States of America
- * E-mail:
| | - Reshma Ramachandran
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States of America
- Department of Poultry Science, Mississippi State University, Starkville, MS, United States of America
| | - Lakshmi Narayanan
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States of America
| | - Shamima Islam
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States of America
| | - Ozdemir Ozan
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States of America
| | - Nancy Freitag
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Mark L. Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States of America
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Kumar S, Bansa YS, Vaishnav D, Narayanan L. Deep Venous Thrombosis and Pulmonary Thromboembolism in a Physically Nonprepared Trekker in the Himalayas: An Autopsy Report. IJMTFM 2021. [DOI: 10.32598/ijmtfm.v11i4.34555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Deep Venous Thrombosis (DVT) and Subsequent Pulmonary Thromboembolism (PTE) in high altitude climbers is a well-known concept. The acclimatization process at high altitude is itself a thrombogenic event. Accordingly, when a physically nonprepared individual with preexisting thrombogenic risk factors attempts trekking at high altitude, they may end up with fatal thromboembolic events. Here, we report a case of a low-lander with multiple thrombogenic risk factors who developed DVT and PTE when he went for a trekking trip in the Himalayas. The risk factors, autopsy findings, and possible mechanism of developing fatal pulmonary embolism, in this case, are discussed here.
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Telmadarrehei T, Tang JD, Raji O, Rezazadeh A, Narayanan L, Shmulsky R, Jeremic D. A Study of the Gut Bacterial Community of Reticulitermes virginicus Exposed to Chitosan Treatment. Insects 2020; 11:E681. [PMID: 33049915 PMCID: PMC7601259 DOI: 10.3390/insects11100681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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] [Received: 08/26/2020] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 01/04/2023]
Abstract
A thorough understanding of microbial communities in the gut of lower termites is needed to develop target-specific and environmentally benign wood protection systems. In this study, the bacterial community from Reticulitermes virginicus was examined by Illumina sequencing of 16S ribosomal RNA (rRNA) spanning the V3 and V4 regions. Prior to library preparation, the termites were subjected to five treatments over an 18-day period: three groups were fed on wood treated with 0.5% chitosan, 25% acetic acid, or water, the fourth group was taken directly from the original collection log, and the fifth group was starved. Metagenomic sequences were analyzed using QIIME 2 to understand the treatments' effects on the dynamics of the gut bacteria. Four dominant phyla were detected: Bacteroidetes (34.4% of reads), Firmicutes (20.6%), Elusimicrobia (15.7%), and Proteobacteria (12.9%). A significant effect of chitosan treatment was observed in two phyla; Firmicutes abundance was significantly lower with chitosan treatment when compared to other groups, while Actinobacteria was lower in unexposed and starved termites. The results suggest that chitosan treatment not only affects the structure of the microbial community in the gut, but other treatments such as starving also cause shifts in termite gut communities.
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Affiliation(s)
- Telmah Telmadarrehei
- Department of Sustainable Bioproducts, Mississippi State University, 201 Locksley Way, Starkville, MS 39759, USA; (O.R.); (L.N.); (R.S.); (D.J.)
| | - Juliet D. Tang
- Forest Products Laboratory, USDA Forest Service, 201 Lincoln Green, Starkville, MS 39759, USA;
| | - Olanrewaju Raji
- Department of Sustainable Bioproducts, Mississippi State University, 201 Locksley Way, Starkville, MS 39759, USA; (O.R.); (L.N.); (R.S.); (D.J.)
- Department of Chemical Engineering and Applied Science, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada
| | - Amir Rezazadeh
- Institute of Food and Agriculture Science, University of Florida, 8400 Picos Road, Ste. 101, Fort Pierce, FL 34945, USA;
| | - Lakshmi Narayanan
- Department of Sustainable Bioproducts, Mississippi State University, 201 Locksley Way, Starkville, MS 39759, USA; (O.R.); (L.N.); (R.S.); (D.J.)
| | - Rubin Shmulsky
- Department of Sustainable Bioproducts, Mississippi State University, 201 Locksley Way, Starkville, MS 39759, USA; (O.R.); (L.N.); (R.S.); (D.J.)
| | - Dragica Jeremic
- Department of Sustainable Bioproducts, Mississippi State University, 201 Locksley Way, Starkville, MS 39759, USA; (O.R.); (L.N.); (R.S.); (D.J.)
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Jeyasree J, Bupesh G, Vasanth S, Beulah JPJ, Pandian K, Anand AV, Vijayakumar TS, Narayanan L. In-vivo Toxicological (Acute) Characterization of Bio-synthesized Silver Nanoparticles in Labeo rohita. Nano BioMed ENG 2020; 12. [DOI: 10.5101/nbe.v12i2.p115-123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
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Archer TM, Mulligan C, Narayanan L, Riggs C, Fellman C, Thomason JM, Wills RW, Boothe DM, Cruz-Espindola C, Harmon R, Mackin AJ. Effects of oral administration of 5 immunosuppressive agents on activated T-cell cytokine expression in healthy dogs. J Vet Intern Med 2020; 34:1206-1213. [PMID: 32052895 PMCID: PMC7255661 DOI: 10.1111/jvim.15729] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/31/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Dogs are often adminstered >1 immunosuppressive medication when treating immune-mediated diseases, and determining whether these different medications affect IL-2 expression would be useful when performing pharmacodynamic monitoring during cyclosporine therapy. HYPOTHESIS/OBJECTIVES To determine the effects of 5 medications (prednisone, cyclosporine, azathioprine, mycophenolate mofetil, and leflunomide) on activated T-cell expression of the cytokines IL-2 and interferon-gamma (IFN-γ). ANIMALS Eight healthy dogs. METHODS Randomized, cross-over study comparing values before and after treatment, and comparing values after treatment among drugs. Dogs were administered each drug at standard oral doses for 1 week, with a washout of at least 21 days. Activated T-cell expression of IL-2 and IFN-γ mRNA was measured by quantitative reverse transcription polymerase chain reaction. Blood drug concentrations were measured for cyclosporine, mycophenolate, and leflunomide metabolites. RESULTS Least squares means (with 95% confidence interval) before treatment for IL-2 (2.91 [2.32-3.50] ΔCt) and IFN-γ (2.33 [1.66-3.00 ΔCt]) values were significantly lower (both P < .001) than values after treatment (10.75 [10.16-11.34] and 10.79 [10.11-11.46] ΔCt, respectively) with cyclosporine. Similarly, least squares means before treatment for IL-2 (1.55 [1.07-2.02] ΔCt) and IFN-γ (2.62 [2.32-2.92] ΔCt) values were significantly lower (both P < .001) than values after treatment (3.55 [3.06-4.00] and 5.22 [4.92-5.52] ΔCt, respectively) with prednisone. Comparing delta cycle threshold values after treatment among drugs, cyclosporine was significantly different than prednisone (IL-2 and IFN-γ both P < .001), with cyclosporine more suppressive than prednisone. CONCLUSIONS AND CLINICAL IMPORTANCE Prednisone and cyclosporine both affected expression of IL-2 and IFN-γ, suggesting that both have the ability to influence results when utilizing pharmacodynamic monitoring of cyclosporine treatment.
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Affiliation(s)
- Todd M Archer
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Charlee Mulligan
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Lakshmi Narayanan
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Caitlin Riggs
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Claire Fellman
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi.,Department of Clinical Sciences, Tufts University, North, MA
| | - John M Thomason
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Robert W Wills
- Department of Population and Preventative Medicine, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Dawn M Boothe
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Crisanta Cruz-Espindola
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Roy Harmon
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Andrew J Mackin
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
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Narayanan L, Mulligan C, Durso L, Thames B, Thomason J, Fellman C, Mackin A, Wills R, Archer T. Recovery of T-cell function in healthy dogs following cessation of oral cyclosporine administration. Vet Med Sci 2020; 6:277-282. [PMID: 31914237 PMCID: PMC7397919 DOI: 10.1002/vms3.230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/30/2019] [Accepted: 12/08/2019] [Indexed: 11/30/2022] Open
Abstract
Cyclosporine is a potent immunosuppressive agent used to treat immune‐mediated disorders in dogs. Secondary infections sometimes necessitate withdrawal of cyclosporine, but it is not known how long it takes for the immune system to recover after cessation of cyclosporine. Our goal was to utilize a validated RT‐qPCR assay in dogs to assess recovery time of the T‐cell cytokines IL‐2 and IFN‐γ after discontinuation of cyclosporine. Six healthy dogs were given oral cyclosporine (10 mg/kg every 12 hr) for 1 week, with samples collected for measurement of cytokine gene expression prior to treatment, and on the last day of therapy. Cyclosporine was then discontinued, and samples were collected daily for an additional 7 days. Results revealed that there was a significant difference in cytokine expression when comparing pre‐treatment and immediate post‐treatment values, corresponding to marked suppression of T‐cell function. There was no significant difference between pre‐treatment values for either cytokine when compared with any day during the recovery period. Cytokine expression, evaluated as a percentage of pre‐treatment baseline samples, demonstrated progressing return of T‐cell function after drug cessation, with full recovery seen in all dogs by Day 4 of the recovery period.
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Affiliation(s)
- Lakshmi Narayanan
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - Charlee Mulligan
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - Lisa Durso
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - Brittany Thames
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - John Thomason
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - Claire Fellman
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - Andrew Mackin
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - Robert Wills
- Department of Pathobiology and Population Medicine, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
| | - Todd Archer
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS, USA
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Coyne CP, Narayanan L. Mebendazole in simultaneous combination with dexamethasone-(C 21-phosphoramidate)-[anti-EGFR] generated utilizing a novel synthesis regimen: dual anti-neoplastic cytotoxicity against pulmonary adenocarcinoma (A549). J Exp Ther Oncol 2019; 13:81-118. [PMID: 31881126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/22/2019] [Indexed: 06/10/2023]
Abstract
PURPOSE The short and long-term resolution of neoplastic conditions with conventional low molecular weight chemotherapeutics is frequently restricted by limitations associated dose-dependent toxic sequelae. Penetration into neoplastic cells occurs non-selectively where their intracellular concentration following simple passive diffusion from the extracellular fluid compartment becomes essentially equivalent to levels found in normal healthy cell populations residing within tissues and organ systems. Selective "targeted" delivery of conventional low molecular weight chemotherapeutics represents one molecular strategy that can both increase potency and reduce dose-dependent toxic sequela. A second strategy is the identification of synergistic or additive combinations of chemotherapeutics and pharmaceutical agents, in addition to the discovery of re-purposed pharmaceutical agents that possess anti-cancer properties. DISCUSSION Mebendazole evoked anti-neoplastic cytotoxicity as both a single entity, and contributed to the potency of the covalent immunoglucocorticoid, dexamethasone-(C21-phosphoramidate)-[anti-EGFR] when applied in a dual-combination challenge against populations of pulmonary adenocarcinoma (A549). In this capacity mebendazole demonstrated a role as a candidate re-purposed pharmaceutical that possessing potential as a [-i-] substitute alternative for conventional tubulin inhibitors in scenarios of idiosyncratic reactions, therapeutic resistance, or anticipated toxic sequelae; [-ii-] a new monotherapy; or [-iii-] a component in the design of new multi-therapeutic protocols.
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Affiliation(s)
- C P Coyne
- Department of Basic Sciences, College of Veterinary Medicine, Wise Center, Mississippi State University, USA
| | - Lakshmi Narayanan
- Department of Basic Sciences, College of Veterinary Medicine, Wise Center, Mississippi State University, USA
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Coyne CP, Narayanan L. Selectively Targeted Anti-Neoplastic Cytotoxicity of Three Immunopharmaceuticals with Covalently Bound Fludarabine, Gemcitabine and Dexamethasone Moieties Synthesized Utilizing Organic Chemistry Reactions in a Multi-Stage Regimen. Curr Pharm Des 2019; 24:1224-1240. [PMID: 29141539 DOI: 10.2174/1381612823666171114155439] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/24/2017] [Accepted: 11/01/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Unintentional passive diffusion of conventional small molecular weight pharmaceuticals across intact membranes of normal healthy cells in tissues and organ systems induces sequelae that limit therapeutic dosage and duration of administration. Selective "targeted" delivery of pharmaceuticals is a molecular strategy that can potentially provide heightened margins-of-safety with greater potency and improved efficacy. MATERIALS AND METHODS Monophosphate analogs of fludarabine, gemcitabine, and dexamethasone were combined with a carbodiimide reagent in the presence of imidazole to produce reactive intermediates that were subsequently covalently bound to monoclonal anti-IGF-1R or anti-EGFR IgG-immunoglobulin. The resulting covalent immunopharmaceutical end-products, fludarabine-(5'-phosphoramidate)-[anti-IGF-1R], gemcitabine-(5'- phosphoramidate)-[anti-IGF-1R], and dexamethasone-(C21-phosphoramidate)-[anti-EGFR] were evaluated by SDS-PAGE/chemiluminescent autoradiography (fragmentation/polymerization detection), UV spectrophotometric absorbance (purity; molar-incorporation-index), cell-ELISA (retained selective binding-avidity), and cell vitality-viability (selectively "targeted" anti-neoplastic cytotoxicity). RESULTS Maximum selectively "targeted" anti-neoplastic cytotoxicity of fludarabine-(5'-phosphoramidate)-[anti- IGF-1R], gemcitabine-(5'-phosphoramidate)-[anti-IGF-1R], and dexamethasone-(C21-phosphoramidate)-[anti- EGFR] was detected at the pharmaceutical-equivalent concentrations of 10-5 M (94.7%), 10-7 M (93.1%), and 10-7 M (64.9%) respectively. DISCUSSION Organic chemistry reactions were optimized in a template multi-stage synthesis regimen for fludarabine-( 5'-phosphoramidate)-[anti-IGF-1R], gemcitabine-(5'-phosphoramidate)-[anti-IGF-1R], and dexamethasone-( C21-phosphoramidate)-[anti-EGFR]. Attributes of the synthesis regimen include; [-i-] covalent bonding of pharmaceutical moeities at high molar incorporation indexes, [-ii-] implementation of organic chemistry reactions in a non-dedicated synthesis regimen allowing component substitution and [-iii-] optional preservation of presynthesized amine-reactive pharmaceutical intermediates for on-demand immunopharmaceutical synthesis. Attributes of the covalent immunopharmaceuticals are; absence of any synthetically introduced chemical groups, retained IgG-immunoglobulin binding-avidity and potent selective "targeted" anti-neoplastic cytotoxic potency. Under in-vivo conditions, supplemental anti-neoplastic cytotoxicity is realized through trophic receptor inhibition and activation of multiple cytotoxic host immune responses.
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Affiliation(s)
- Cody P Coyne
- Department of Basic Sciences, College of Veterinary Medicine at Wise Center, Mississippi State University, Mississippi State, Mississippi 39762, United States.,Sustainability Bioproducts Laboratory, Forest, Wildlife Research Center, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Lakshmi Narayanan
- Department of Basic Sciences, College of Veterinary Medicine at Wise Center, Mississippi State University, Mississippi State, Mississippi 39762, United States
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Narayanan L, Abdelrasheed NSG, Nasser RN, Menon S. Dimensional Structure of the Arabic Positive Affect and Negative Affect Scale Adapted From its English Form. Psychol Rep 2019; 123:2597-2616. [PMID: 31333074 DOI: 10.1177/0033294119863293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The purpose of this study was to examine the dimensional structure of the Arabic version of the Positive Affect and Negative Affect Schedule using a sample of undergraduate students from a private university in the Sultanate of Oman. Confirmatory factor analysis was conducted to test four preconceptualized item-fit models: a one-factor structure model, a two-factor model using a factor structure of items converging on Positive Affect and Negative Affect, a correlated two-factor model, and finally the correlated three-factor model. Strongest support was found for the correlated two-factor model. A recent study provided further evidence of the robust structure of the Positive Affect and Negative Affect Schedule using the two-factor model. This study tested the model in a non-Western culture and a population that was very different from that in previous studies. The implications of these findings and recommendations are discussed herein.
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Affiliation(s)
| | | | - Ramzi Naim Nasser
- Education Department, University of Sharjah, Sharjah, United Arab Emirates
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Coyne CP, Narayanan L. Carnosic Acid, Tangeretin, and Ginkgolide-B Anti-neoplastic Cytotoxicity in Dual Combination with Dexamethasone-[anti-EGFR] in Pulmonary Adenocarcinoma (A549). Anticancer Agents Med Chem 2019; 19:802-819. [DOI: 10.2174/1871520619666181204100226] [Citation(s) in RCA: 6] [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] [Received: 12/07/2017] [Revised: 06/06/2018] [Accepted: 10/08/2018] [Indexed: 12/18/2022]
Abstract
Background:Traditional chemotherapeutics of low-molecular weight diffuse passively across intact membrane structures of normal healthy cells found in tissues and organ systems in a non-specific unrestricted manner which largely accounts for the induction of most sequelae which restrict dosage, administration frequency, and duration of therapeutic intervention. Molecular strategies that offer enhanced levels of potency, greater efficacy and broader margins-of-safety include the discovery of alternative candidate therapeutics and development of methodologies capable of mediating properties of selective “targeted” delivery.Materials and Methods:The covalent immunopharmaceutical, dexamethasone-(C21-phosphoramidate)-[anti- EGFR] was synthesized utilizing organic chemistry reactions that comprised a multi-stage synthesis regimen. Multiple forms of analysis were implemented to vadliate the successful synthesis (UV spectrophotometric absorbance), purity and molar-incorporation-index (UV spectrophotometric absorbance, chemical-based protein determination), absence of fragmentation/polymerization (SDS-PAGE/chemiluminescent autoradiography), retained selective binding-avidity of IgG-immunoglobulin (cell-ELISA); and selectively “targeted” antineoplastic cytotoxicity (biochemistry-based cell vitality/viability assay).Results:The botanicals carnosic acid, ginkgolide-B and tangeretin, each individually exerted maximum antineoplastic cytotoxicity levels of 58.1%, 5.3%, and 41.1% respectively against pulmonary adenocarcinoma (A549) populations. Dexamethasone-(C21-phosphoramidate)-[anti-EGFR] formulated at corticosteroid/ glucocorticoid equivalent concentrations produced anti-neoplastic cytotoxicity at levels of 7.7% (10-9 M), 26.9% (10-8 M), 64.9% (10-7 M), 69.9% (10-6 M) and 73.0% (10-5 M). Ccarnosic acid, ginkgolide-B and tangeretin in simultaneous dual-combination with dexamethasone-(C21-phosphoramidate)-[anti-EGFR] exerted maximum anti-neoplastic cytotoxicity levels of 70.5%, 58.6%, and 69.7% respectively.Discussion:Carnosic acid, ginkgolide-B and tangeretin botanicals exerted anti-neoplastic cytotoxicity against pulmonary adenocarcinoma (A549) which additively contributed to the anti-neoplastic cytotoxic potency of the covalent immunopharmaceutical, dexamethasone-(C21-phosphoramidate)-[anti-EGFR]. Carnosic acid and tangeretin were most potent in this regard both individually and in dual-combination with dexamethasone-(C21- phosphoramidate)-[anti-EGFR]. Advantages and attributes of carnosic acid and tangeretin as potential monotherapeutics are a wider margin-of-safety of conventional chemotherapeutics which would readily complement the selective “targeted” delivery properties of dexamethasone-(C21-phosphoramidate)-[anti-EGFR] and possibly other covalent immunopharmaceuticals in addition to providing opportunities for the discovery of combination therapies that provide heightened levels of anti-neoplastic efficacy.
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Affiliation(s)
- Cody P. Coyne
- Department of Basic Sciences, College of Veterinary Medicine at Wise Center, Mississippi State University, Mississippi 39762, United States
| | - Lakshmi Narayanan
- Department of Basic Sciences, College of Veterinary Medicine at Wise Center, Mississippi State University, Mississippi 39762, United States
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Riggs C, Narayanan L, Mulligan C, Wills R, Mackin A, Fellman C, Thomason J, Archer T. Alterations in activated T-cell cytokine expression in healthy dogs over the initial 7 days of twice daily dosing with oral cyclosporine. J Vet Pharmacol Ther 2019; 42:385-391. [PMID: 30933369 DOI: 10.1111/jvp.12762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/08/2019] [Accepted: 02/20/2019] [Indexed: 01/10/2023]
Abstract
Cyclosporine is a powerful T-cell inhibitor used in the treatment of immune-mediated and inflammatory diseases in the dog. There is limited information on how to best monitor patients on cyclosporine therapy. Currently, pharmacokinetic and pharmacodynamic assays are available. Pharmacokinetic assays that measure the concentration of cyclosporine in the blood are used to assess if an appropriate drug concentration has been achieved; however, target blood drug concentrations have not been shown to reliably correlate with suppression of T-cell function in the dog. In human transplant recipients, therapeutic drug monitoring has shifted to include pharmacodynamic-based monitoring. Our laboratory has validated a RT-qPCR assay to measure the pharmacodynamic effects of cyclosporine in the dog. In this study, activated T-cell expression of IL-2 and IFN-γ was measured using RT-qPCR daily for 7 consecutive days in 8 healthy Walker hounds receiving oral cyclosporine at a dosage of 10 mg/kg every 12 hr. Cytokine production was found to be markedly decreased within 24 hr after the initiation of cyclosporine and remained significantly decreased for the duration of the project. Based on these results, cyclosporine causes a rapid drop in T-cell cytokine production that is sustained with continued dosing in healthy dogs. Although performed in healthy dogs, this study demonstrated a marked decrease in cytokine suppression within 24 hr of drug administration, suggesting that pharmacodynamic monitoring of cyclosporine's effects on T cells could be considered within several days of commencing therapy in dogs suffering from life-threatening immune-mediated disorders.
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Affiliation(s)
- Caitlin Riggs
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Lakshmi Narayanan
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Charlee Mulligan
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Robert Wills
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Andrew Mackin
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Claire Fellman
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - John Thomason
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Todd Archer
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
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Dandrieux JRS, Narayanan L, Firestone S, Archer TM, Mansfield CS. Effect of immunosuppressive drugs on cytokine production in canine whole blood stimulated with lipopolysaccharide or a combination of ionomycin and phorbol 12-myristate 13-acetate. Vet Med Sci 2019; 5:199-205. [PMID: 30663866 PMCID: PMC6498811 DOI: 10.1002/vms3.143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A pharmacodynamic assay has been previously developed to monitor ciclosporin treatment in dogs by assessing inhibition of cytokine transcription after whole blood stimulation with 12-myristate 13-1 acetate and ionomycin (PMA/I). In this study, whole blood stimulation with either PMA/I or lipopolysaccharide (LPS) was used to assess the effect of multiple drugs (azathioprine, ciclosporin, mycophenolate, leflunomide and prednisone) after a 7-day treatment course on production of cytokines measured with a multiplex assay in healthy dogs (n = 4 for each treatment). Interleukin-10 (IL-10), interferon gamma (IFNγ) and tumour necrosis factor alpha (TNFα) were significantly activated by PMA/I stimulation and IL-6, IL-10 and TNFα by LPS stimulation, in the absence of immunosuppressive drugs. After ciclosporin treatment, IL-10, IFNγ and TNFα production was significantly reduced after stimulation with PMA/I compared to pre-treatment. After prednisone treatment, TNFα production was significantly reduced after stimulation with PMA/I or LPS compared to pre-treatment. No significant change was observed after treatment with azathioprine, leflunomide or mycophenolate. This methodology may be useful to monitor dogs not only treated with ciclosporin, but also with prednisone or a combination of both. Further studies are needed to assess the use of this assay in a clinical setting.
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Affiliation(s)
- Julien R S Dandrieux
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, University of Melbourne, Werribee, Vic, Australia
| | - Lakshmi Narayanan
- Department of Sustainable Bioproducts, Mississippi State University, Starkville, MS, USA
| | - Simon Firestone
- Faculty of Veterinary and Agricultural Sciences, Asia-Pacific Centre for Animal Health, University of Melbourne, Parkville, Vic, Australia
| | - Todd M Archer
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, MS, Mississippi
| | - Caroline S Mansfield
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, University of Melbourne, Werribee, Vic, Australia
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Coyne CP, Narayanan L. Anti-neoplastic cytotoxicity by complementary simultaneous selective “targeted” delivery for pulmonary adenocarcinoma: fludarabine-(5′-phosphoramidate)-[anti-IGF-1R] in dual-combination with dexamethasone-(C21-phosphoramidate)-[anti-EGFR]. J Pharm Investig 2018. [DOI: 10.1007/s40005-018-0401-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Coyne CP, Narayanan L. Gemcitabine-(5'-phosphoramidate)-[anti-IGF-1R]: molecular design, synthetic organic chemistry reactions, and antineoplastic cytotoxic potency in populations of pulmonary adenocarcinoma (A549). Chem Biol Drug Des 2017; 89:379-399. [PMID: 27561602 PMCID: PMC5396302 DOI: 10.1111/cbdd.12845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 03/14/2016] [Revised: 08/12/2016] [Accepted: 08/19/2016] [Indexed: 02/06/2023]
Abstract
One molecular-based approach that increases potency and reduces dose-limited sequela is the implementation of selective 'targeted' delivery strategies for conventional small molecular weight chemotherapeutic agents. Descriptions of the molecular design and organic chemistry reactions that are applicable for synthesis of covalent gemcitabine-monophosphate immunochemotherapeutics have to date not been reported. The covalent immunopharmaceutical, gemcitabine-(5'-phosphoramidate)-[anti-IGF-1R] was synthesized by reacting gemcitabine with a carbodiimide reagent to form a gemcitabine carbodiimide phosphate ester intermediate which was subsequently reacted with imidazole to create amine-reactive gemcitabine-(5'-phosphorylimidazolide) intermediate. Monoclonal anti-IGF-1R immunoglobulin was combined with gemcitabine-(5'-phosphorylimidazolide) resulting in the synthetic formation of gemcitabine-(5'-phosphoramidate)-[anti-IGF-1R]. The gemcitabine molar incorporation index for gemcitabine-(5'-phosphoramidate)-[anti-IGF-R1] was 2.67:1. Cytotoxicity Analysis - dramatic increases in antineoplastic cytotoxicity were observed at and between the gemcitabine-equivalent concentrations of 10-9 M and 10-7 M where lethal cancer cell death increased from 0.0% to a 93.1% maximum (100.% to 6.93% residual survival), respectively. Advantages of the organic chemistry reactions in the multistage synthesis scheme for gemcitabine-(5'-phosphoramidate)-[anti-IGF-1R] include their capacity to achieve high chemotherapeutic molar incorporation ratios; option of producing an amine-reactive chemotherapeutic intermediate that can be preserved for future synthesis applications; and non-dedicated organic chemistry reaction scheme that allows substitutions of either or both therapeutic moieties, and molecular delivery platforms.
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Affiliation(s)
- Cody P. Coyne
- Department of Basic SciencesCollege of Veterinary MedicineWise CenterMississippi State UniversityMississippi StateMSUSA
- College of Veterinary MedicineWise CenterMississippi State UniversityMississippi StateMSUSA
| | - Lakshmi Narayanan
- Department of Basic SciencesCollege of Veterinary MedicineWise CenterMississippi State UniversityMississippi StateMSUSA
- College of Veterinary MedicineWise CenterMississippi State UniversityMississippi StateMSUSA
- Present address: Fishery and Wildlife Research CenterMississippi State UniversityLocksley Way 201Mississippi StateMSUSA
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Coyne CP, Narayanan L. Dexamethasone-(C21-phosphoramide)-[anti-EGFR]: molecular design, synthetic organic chemistry reactions, and antineoplastic cytotoxic potency against pulmonary adenocarcinoma (A549). Drug Des Devel Ther 2016; 10:2575-97. [PMID: 27574398 PMCID: PMC4990379 DOI: 10.2147/dddt.s102075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE Corticosteroids are effective in the management of a variety of disease states, such as several forms of neoplasia (leukemia and lymphoma), autoimmune conditions, and severe inflammatory responses. Molecular strategies that selectively "target" delivery of corticosteroids minimize or prevents large amounts of the pharmaceutical moiety from passively diffusing into normal healthy cell populations residing within tissues and organ systems. MATERIALS AND METHODS The covalent immunopharmaceutical, dexamethasone-(C21-phosphoramide)-[anti-EGFR] was synthesized by reacting dexamethasone-21-monophosphate with a carbodiimide reagent to form a dexamethasone phosphate carbodiimide ester that was subsequently reacted with imidazole to create an amine-reactive dexamethasone-(C21-phosphorylimidazolide) intermediate. Monoclonal anti-EGFR immunoglobulin was combined with the amine-reactive dexamethasone-(C21-phosphorylimidazolide) intermediate, resulting in the synthesis of the covalent immunopharmaceutical, dexamethasone-(C21-phosphoramide)-[anti-EGFR]. Following spectrophotometric analysis and validation of retained epidermal growth factor receptor type 1 (EGFR)-binding avidity by cell-ELISA, the selective anti-neoplasic cytotoxic potency of dexamethasone-(C21-phosphoramide)-[anti-EGFR] was established by MTT-based vitality stain methodology using adherent monolayer populations of human pulmonary adenocarcinoma (A549) known to overexpress the tropic membrane receptors EGFR and insulin-like growth factor receptor type 1. RESULTS The dexamethasone:IgG molar-incorporation-index for dexamethasone-(C21-phosphoramide)-[anti-EGFR] was 6.95:1 following exhaustive serial microfiltration. Cytotoxicity analysis: covalent bonding of dexamethasone to monoclonal anti-EGFR immunoglobulin did not significantly modify the ex vivo antineoplastic cytotoxicity of dexamethasone against pulmonary adenocarcinoma at and between the standardized dexamethasone equivalent concentrations of 10(-9) M and 10(-5) M. Rapid increases in antineoplastic cytotoxicity were observed at and between the dexamethasone equivalent concentrations of 10(-9) M and 10(-7) M where cancer cell death increased from 7.7% to a maximum of 64.9% (92.3%-35.1% residual survival), respectively, which closely paralleled values for "free" noncovalently bound dexamethasone. DISCUSSION Organic chemistry reaction regimens were optimized to develop a multiphase synthesis regimen for dexamethasone-(C21-phosphoramide)-[anti-EGFR]. Attributes of dexamethasone-(C21-phosphoramide)-[anti-EGFR] include a high dexamethasone molar incorporation-index, lack of extraneous chemical group introduction, retained EGFR-binding avidity ("targeted" delivery properties), and potential to enhance long-term pharmaceutical moiety effectiveness.
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Affiliation(s)
| | - Lakshmi Narayanan
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, USA
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Gopikrishna V, Sibi S, Archana D, Pradeep Kumar AR, Narayanan L. An in vivo assessment of the influence of needle gauges on endodontic irrigation flow rate. J Conserv Dent 2016; 19:189-93. [PMID: 27099430 PMCID: PMC4815552 DOI: 10.4103/0972-0707.178708] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Aim: The aim of this clinical study was to assess the influence of irrigation needle gauge on endodontic irrigation flow rates. Settings and Design: In vivo assessment. Materials and Methods: Five specialist endodontists performed intracanal irrigation procedures on 50 mesiobuccal canal of mandibular first molars using three different irrigation needle gauges. Data of time taken for irrigation was recorded by an irrigation testing system and analyzed using independent sample “T” test and one-way analysis of variance (ANOVA) test. The level of significance was set at P < 0.05. Statistical Analysis Used: The following tests were used for the statistical analysis: Independent sample “T” test, one-way ANOVA test, and post hoc multiple comparison was carried out using Tukey's honest significant difference (HSD) test using Statistical Package for the Social Sciences (SPSS) version 16 for Windows. Results: The average flow rate of 26 gauge was 0.27 mLs−1, of 27 gauge was 0.19 mLs−1, and of 30 gauge was 0.09 mls−1. There was statistical significance among the gauges (P < 0.001). 26 gauge had highest flow rate when compared with other groups followed by 27 gauge and 30 gauge respectively. The operator variability for flow rate of three endodontic irrigation needle gauges (26 gauge, 27 gauge, and 30 gauge) was found to be not significant. Conclusions: Needle gauge has significant influence on endodontic irrigation flow rate.
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Affiliation(s)
- Velayutham Gopikrishna
- Dr M.G.R. Educational and Research Institute University, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Swamy Sibi
- Dr M.G.R. Educational and Research Institute University, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Durvasulu Archana
- Dr M.G.R. Educational and Research Institute University, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India
| | | | - Lakshmi Narayanan
- Dr M.G.R. Educational and Research Institute University, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India
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Ganapathy VP, Palaniswamy VA, Vinod P, Narayanan L, Sahoo T, Ranjan Das R. Severe Symptomatic Hypophosphatemia With Thrombocytopenia in a Child With Diabetic Ketoacidosis. J Compr Ped 2015; 6. [DOI: 10.17795/compreped-28020] [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: 09/18/2023]
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Coyne CP, Narayanan L. Fludarabine- (C 2- methylhydroxyphosphoramide)- [anti-IGF-1R]: Synthesis and Selectively "Targeted"Anti-Neoplastic Cytotoxicity against Pulmonary Adenocarcinoma (A549). ACTA ACUST UNITED AC 2015; 4. [PMID: 26613088 DOI: 10.4172/2325-9604.1000129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Many if not most conventional small molecular weight chemotherapeutics are highly potent against many forms of neoplastic disease. Unfortunately, majority of an administered dose unintentionally diffuses passively into normal tissues and healthy organ systems following intravenous administration. One strategy for both increasing potency and reducing dose-limited sequela is the selective "targeted" delivery of conventional chemotherapeutic agents. MATERIALS AND METHODS The fludarabine-(C2- methylhydroxyphosphoramide)-[anti-IGF-1R] was synthesized by initially reacting fludarabine with a carbodiimide to form a fludarabine carbodiimide phosphate ester intermediate that was subsequently reacted with imidazole to create an amine-reactive fludarabine- (C2-phosphorylimidazolide) intermediate. Monoclonal anti-IGF-1R immunoglobulin was combined with the amine-reactive fludarabine- (C2-phosphorylimidazolide) intermediate resulting in the synthesis of covalent fludarabine-(C2-methylhydroxyphosphoramide)- [anti-IGF-1R] immunochemotherapeutic. Residual fludarabine and un-reacted reagents were removed by serial microfiltration (MWCO 10,000) and monitored by analytical-scale HP-TLC. Retained IGF-1R binding-avidity of fludarabine-(C2- methylhydroxyphosphoramide)-[anti-IGF-1R] was established by cell-ELISA using pulmonary adenocarcinoma cell (A549) which over-expresses IGF-1R and EGFR. Anti-neoplastic cytotoxic potency of fludarabine-(C2-methylhydroxyphosphoramide)-[anti- IGF-1R] was determined against pulmonary adenocarcinoma (A549) using an MTT-based vitality stain methodology. RESULTS The fludarabine molar-incorporation-index for fludarabine- (C2-methylhydroxyphosphoramide)-[anti-IGF-R1] was 3.67:1 while non-covalently bound fludarabine was not detected by analytical scale HP-TLC following serial micro-filtration. Size-separation fludarabine-(C2-methylhydroxyphosphoramide)-[anti- IGF-1R] by SDS-PAGE with chemo luminescent autoradiography detected only a single 150-kDa band. Cell-ELISA of fludarabine- (C2-methylhydroxyphosphoramide)-[anti-IGF-1R] measuring total immunoglobulin bound to exterior surface membranes of pulmonary adenocarcinoma (A549) increased with elevations in immunoglobulin-equivalent concentrations of the covalent fludarabine immunochemotherapeutic. Between the fludarabine-equivalent concentrations of 10-10 M and 10-5 M both fludarabine-(C2- methylhydroxyphosphoramide)-[anti-IGF-1R] and fludarabine had ex-vivo anti-neoplastic cytotoxic potency levels that increased rapidly between the fludarabine-equivalent concentrations of 10-6 M and 10-5 M where cancer cell death percentages increased from 24.4% to a maximum of 94.7% respectively. CONCLUSION The molecular design and organic chemistry reaction schemes were developed for synthesizing fludarabine-(C2- methylhydroxyphosphoramide)-[anti-IGF-1R] which possessed both properties of selective "targeted" delivery and anti-neoplastic cytotoxic potency equivalent to fludarabine chemotherapeutic.
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Affiliation(s)
- C P Coyne
- Department of Basic Sciences, College of Veterinary Medicine, Wise Center, Mississippi State University, Mississippi State, Mississippi, USA ; College of Veterinary Medicine, Mississippi State University, Mississippi, USA
| | - Lakshmi Narayanan
- Department of Basic Sciences, College of Veterinary Medicine, Wise Center, Mississippi State University, Mississippi State, Mississippi, USA
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Narayanan L, Murray AD. What is the role of neuroimaging in dementia? A review. Imaging 2014. [DOI: 10.1259/img.20120015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Michealraj KA, Jatana N, Jafurulla, Narayanan L, Chattopadhyay A, Thelma BK. Functional characterization of rare variants in human dopamine receptor D4 gene by genotype-phenotype correlations. Neuroscience 2014; 262:176-89. [PMID: 24406443 DOI: 10.1016/j.neuroscience.2013.12.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/28/2013] [Accepted: 12/20/2013] [Indexed: 01/11/2023]
Abstract
Next generation sequencing technologies have facilitated a notable shift from common disease common variant hypothesis to common disease rare variant, as also witnessed in recent literature on schizophrenia. Dopamine receptor D4 (DRD4), a G-protein-coupled receptor is associated with psychiatric disorders and has high affinity for atypical antipsychotic clozapine. We investigated the functional role of rare genetic variants in DRD4 which may have implications for translational medicine. CHO-K1 cells independently expressing four rare non-synonymous variants of DRD4 namely R237L, A281P, S284G located in the third cytosolic loop and V194G, located in the fifth transmembrane domain were generated. Their genotype-phenotype correlations were evaluated using [³H]spiperone binding, G-protein activation and molecular dynamics-simulation studies. A281P and S284G were functionally similar to wildtype (WT). With R237L, potency of dopamine and quinpirole reduced ∼sixfold and threefold respectively compared to WT; [³H]spiperone binding studies showed a reduction in total number of binding sites (∼40%) but not binding affinity, in silico docking studies revealed that binding of both dopamine and spiperone to R237L was structurally similar to WT. Of note, V194G variant failed to inhibit forskolin-stimulated adenylate cyclase activity and phosphorylate extracellular signal-regulated kinase; showed significant reduction in binding affinity (K(d)=2.16 nM) and total number of binding sites (∼66%) compared to WT in [³H]spiperone binding studies; and ligand docking studies showed that binding of dopamine and spiperone is superficial due to probable structural alteration. Transmembrane variant V194G in DRD4.4 results in functional alteration warranting continuing functional analysis of rare variants.
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Affiliation(s)
- K A Michealraj
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - N Jatana
- Bioinformatics Infrastructure Facility, Sri Venkateswara College, New Delhi, India
| | - Jafurulla
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - L Narayanan
- Bioinformatics Infrastructure Facility, Sri Venkateswara College, New Delhi, India
| | - A Chattopadhyay
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - B K Thelma
- Department of Genetics, University of Delhi South Campus, New Delhi, India.
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24
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Ünlü ES, Narayanan L, Gordon DM. Characterization of fungal RTG2 genes in retrograde signaling of Saccharomyces cerevisiae. FEMS Yeast Res 2013; 13:495-503. [PMID: 23711018 PMCID: PMC3814403 DOI: 10.1111/1567-1364.12055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 03/26/2013] [Revised: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 12/01/2022] Open
Abstract
Changes in the functional status of mitochondria result in the transcriptional activation of a subset of nuclear-encoded genes in a process referred to as retrograde signaling. In Saccharomyces cerevisiae, this molecular link between mitochondria and the nuclear genome is controlled by three key signaling proteins: Rtg1p, Rtg2p, and Rtg3p. Although the retrograde signaling response has been well characterized in S. cerevisiae, very little is known about this pathway in other fungi. In this study, we selected four species having uncharacterized open reading frames (ORFs) with more than 66% amino acid identity to Rtg2p for further analysis. To determine whether these putative RTG2 ORFs encoded bona fide regulators of retrograde signaling, we tested their ability to complement the defects associated with the S. cerevisiae rtg2Δ mutant. Specifically, we tested for complementation of citrate synthase (CIT2) and aconitase (ACO1) at the transcript and protein levels, glutamate auxotrophy, and changes in the interaction between Rtg2p and the negative regulator Mks1p. Our findings show that all four Rtg2p homologs are functional upon activation of retrograde signaling, although their degree of complementation varied. In addition, all Rtg2p homologs showed a marked reduction in Mks1p binding, which may contribute to their altered responses to retrograde signaling.
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Affiliation(s)
- Ercan Selçuk Ünlü
- Department of Biological Sciences, Mississippi State UniversityMississippi State, MS, USA
- Department of Chemistry, Abant Izzet Baysal UniversityBolu, Turkey
| | - Lakshmi Narayanan
- Department of Biological Sciences, Mississippi State UniversityMississippi State, MS, USA
| | - Donna M Gordon
- Department of Biological Sciences, Mississippi State UniversityMississippi State, MS, USA
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25
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Asirvatham R, Antonysamy A, Rajkumar P, Narayanan L. Anticancer activity of <i>Jasminum angustifolium</i> Linn against Ehrlich ascites carcinoma cells bearing mice. ACTA ACUST UNITED AC 2012. [DOI: 10.5455/jeim.050612.or.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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26
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Gopal M, D’Souza L, K. JB, Inbanathan A, Nayar P, Eswarappa K, Isac S, Narayanan L, Kumar VA, Chaudhury SK, Jogdand P, Kumar N. Book Reviews. Sociological Bulletin 2009; 58:168-188. [DOI: 10.1177/0038022920090307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Affiliation(s)
- Meena Gopal
- Research Centre for Women’s Studies, SNDT Women’s
University, Mumbai
| | | | - Jose Boban K.
- PG Department of Sociology, Loyola College of Social
Sciences, Thiruvananthapuram
| | - Anand Inbanathan
- Centre for Study of Social Change and Development
Institute for Social and Economic Change, Bangalore
| | - P.K.B. Nayar
- Centre for Gerontological Studies, Thiruvananthapuram
| | | | | | - Lakshmi Narayanan
- Department of Foundations of Education National
University of Educational Planning and Administration, New Delhi
| | - V. Anil Kumar
- Centre for Political Institutions, Governance and
Development Institute for Social and Economic Change, Bengaluru
| | | | | | - Nikhlesh Kumar
- Department of Sociology, North-Eastern Hill University,
Shillong
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27
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Narayanan L, Buttler GW, Yu KO, Mattie DR, Fisher JW. Sensitive high-performance liquid chromatography method for the determination of low levels of perchlorate in biological samples. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 788:393-9. [PMID: 12705980 DOI: 10.1016/s1570-0232(03)00037-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [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: 10/27/2022]
Abstract
A rapid and sensitive high-performance liquid chromatography (HPLC) method was developed to detect perchlorate in tissues of male and female rats, both pregnant and lactating (including milk) after administration of perchlorate. Supernatants of ethanol precipitated rat fluids and tissues were evaporated to dryness under nitrogen and reconstituted in deionized water. Reconstituted samples were injected into HPLC system coupled with conductivity detection. Isocratic separation of perchlorate was achieved using an anion-exchange column with sodium hydroxide as mobile phase and a conductivity detector. In this method, perchlorate showed a linear response range from 5 to 100 ng/ml. The lower detection limits for perchlorate in fluids and tissues of rats were 3-6 ng/ml and 0.007-0.7 mg/kg, respectively. The described method has the unique advantage over the existing methods of determining low traces of perchlorate in different biological matrices without complex sample preparation.
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Affiliation(s)
- L Narayanan
- GEO-CENTERS, Inc., 2856 G Street, Wright-Patterson AFB, OH 45433-7400, USA.
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28
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Glazer P, Narayanan L, Liskay M, Campisi D. Over-expression of the DNA mismatch repair factor, PMS2, confers ionizing radiation resistance and hypermutability. Int J Radiat Oncol Biol Phys 2002. [DOI: 10.1016/s0360-3016(02)03145-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Xu XS, Narayanan L, Dunklee B, Liskay RM, Glazer PM. Hypermutability to ionizing radiation in mismatch repair-deficient, Pms2 knockout mice. Cancer Res 2001; 61:3775-80. [PMID: 11325851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
DNA mismatch repair (MMR) has been shown to play a role in the cytotoxicity of ionizing radiation (IR), as cell lines established from MMR-deficient mice exhibit higher clonogenic survival after IR than do cell lines from wild-type littermates. To test whether this tolerance phenotype would render MMR-deficient animals hypermutable to IR, we compared IR mutagenesis of Pms2-deficient versus wild-type transgenic mice carrying a lambda shuttle vector for mutation detection. In Pms2 nullizygous animals, the mutation frequency in the supFG1 reporter gene was increased from 210 x 10(-5) in untreated animals to 734 x 10(-5) after 6 Gy of IR (an increase of 524 mutants per 10(5)), whereas the frequency in wild-type mice increased from 1.9 x 10(-5) to 10.2 x 10(-5) (an increase of only 8.3 mutants per 10(5)). Similarly, when the lambda cII gene was used as a reporter, the mutation frequency in nullizygous mice was increased from 16.3 x 10(-5) to 42.3 x 10(-5) after IR (an increase of 26.0 x 10(-5)), whereas the frequency in wild-type mice increased from 2.4 x 10(-5) to 9.4 x 10(-5) (an increase of only 7.0 x 10(-5)). The pattern of IR-induced mutations in the MMR-deficient animals was notable for single bp deletions and insertions in mononucleotide repeat sequences, along with a slight increase in transversions. Overall, these results suggest that MMR-deficiency confers hypermutability to IR, and that much of this hypermutability can be attributed to induced instability of simple sequence repeats. Hence, MMR influences not only the survival but also the mutability of cells in response to IR.
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Affiliation(s)
- X S Xu
- Departments of Therapeutic Radiology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8040, USA
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Abstract
Triplex-forming oligonucleotides (TFOs) recognize and bind to specific duplex DNA sequences and have been used extensively to modify gene function in cells. Although germ line mutations can be incorporated by means of embryonic stem cell technology, little progress has been made toward introducing mutations in somatic cells of living organisms. Here we demonstrate that TFOs can induce mutations at specific genomic sites in somatic cells of adult mice. Mutation detection was facilitated by the use of transgenic mice bearing chromosomal copies of the supF and cII reporter genes. Mice treated with a supF-targeted TFO displayed about fivefold greater mutation frequencies in the supF gene compared with mice treated with a scrambled sequence control oligomer. No mutagenesis was detected in the control gene (cII) with either oligonucleotide. These results demonstrate that site-specific, TFO-directed genome modification can be accomplished in intact animals.
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Affiliation(s)
- K M Vasquez
- Departments of Therapeutic Radiology and Genetics, Yale University School of Medicine, Boyer Center for Molecular Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
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31
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Zeng M, Narayanan L, Xu XS, Prolla TA, Liskay RM, Glazer PM. Ionizing radiation-induced apoptosis via separate Pms2- and p53-dependent pathways. Cancer Res 2000; 60:4889-93. [PMID: 10987303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The cytotoxicity of ionizing radiation (IR) has been associated with both the p53 pathway and with DNA mismatch repair (MMR). p53 mediates cell cycle arrest and apoptosis in response to X-ray damage, whereas the MMR complex is thought to recognize damaged bases and initiate a signal transduction pathway that can include phosphorylation of p53. To determine whether p53 and MMR mediate X-ray cytotoxicity via the same pathway, mice with targeted disruptions in either the p53 gene or the MutL homologue MMR gene Pms2 were interbred and primary fibroblasts were established from the progeny with genotypes of either wild type, p53 null, Pms2 null, or double null. Cells with either p53 or Pms2 separately disrupted showed reduced levels of apoptosis after IR in comparison with wild type, but the double null cells showed even lower levels, consistent with nonoverlapping roles for p53 and PMS2 in the X-ray response. In transformed cell lines established from the primary cells at early passage, similar differences in the apoptotic response to IR were seen, and clonogenic survival assays following low dose rate IR further showed that nullizygosity for Pms2 confers increased survival on cells in both wild-type and p53 null backgrounds. These results indicate that both p53 and MMR contribute to X-ray-induced apoptosis and that the role of MMR in the cytotoxicity of IR does not depend on p53.
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Affiliation(s)
- M Zeng
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-8040, USA
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32
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Yuan J, Narayanan L, Rockwell S, Glazer PM. Diminished DNA repair and elevated mutagenesis in mammalian cells exposed to hypoxia and low pH. Cancer Res 2000; 60:4372-6. [PMID: 10969780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The tumor microenvironment is characterized by regions of fluctuating and chronic hypoxia, low pH, and nutrient deprivation. It has been proposed that this unique tissue environment itself may constitute a major cause of the genetic instability seen in cancer. To investigate possible mechanisms by which the tumor microenvironment might contribute to genetic instability, we asked whether the conditions found in solid tumors could influence cellular repair of DNA damage. Using an assay for repair based on host cell reactivation of UV-damaged plasmid DNA, cells exposed to hypoxia and low pH were found to have a diminished capacity for DNA repair compared with control cells grown under standard culture conditions. In addition, cells cultured under hypoxia at pH 6.5 immediately after UV irradiation had elevated levels of induced mutagenesis compared with those maintained in standard growth conditions. Taken together, the results suggest that cellular repair functions may be impaired under the conditions of the tumor microenvironment, causing hypermutability to DNA damage. This alteration in repair capacity may constitute an important mechanism underlying the genetic instability of cancer cells in vivo.
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Affiliation(s)
- J Yuan
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-8040, USA
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33
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Andrew SE, Xu XS, Baross-Francis A, Narayanan L, Milhausen K, Liskay RM, Jirik FR, Glazer PM. Mutagenesis in PMS2- and MSH2-deficient mice indicates differential protection from transversions and frameshifts. Carcinogenesis 2000; 21:1291-5. [PMID: 10874005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
DNA mismatch repair (MMR) deficiency leads to an increased mutation frequency and a predisposition to neoplasia. 'Knockout' mice deficient in the MMR proteins Msh2 and Pms2 crossed with mutation detection reporter (supF, lacI and cII) transgenic mice have been used to facilitate a comparison of the changes in mutation frequency and spectra. We find that the mutation frequency was consistently higher in Msh2-deficient mice than Pms2-deficient mice. The lacI target gene, which is highly sensitive to point mutations, demonstrated that both Msh2- and Pms2-deficient mice accumulate transition mutations as the predominant mutation. However, when compared with Msh2(-/-) mice, lacI and cII mutants from Pms2-deficient mice revealed an increased proportion of +/-1 bp frameshift mutations and a corresponding decrease in transversion mutations. The supF target gene, which is sensitive to frameshift mutations, and the cII target gene revealed a strong tendency for -1 bp deletions over +1 bp insertions in Msh2(-/-) compared with Pms2(-/-) mice. These data indicate that Msh2 and Pms2 deficiency have subtle but differing effects on mutation avoidance which may contribute to the differences in tumor spectra observed in the two 'knockout' mouse models. These variances in mutation accumulation may also play a role, in part, in the differences seen in prevalence of MSH2 and PMS2 germline mutations in hereditary non-polyposis colorectal cancer patients.
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Affiliation(s)
- S E Andrew
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7 Canada.
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34
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Fisher J, Todd P, Mattie D, Godfrey D, Narayanan L, Yu K. Preliminary development of a physiological model for perchlorate in the adult male rat: a framework for further studies. Drug Chem Toxicol 2000; 23:243-58. [PMID: 10711400 DOI: 10.1081/dct-100100113] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- J Fisher
- Operational Toxicology Branch, Human Effectiveness Directorate, WPAFB, OH 45433-7400, USA
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35
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Zeng M, Narayanan L, Glazer P. The influence of the DNA mismatch repair gene, Pms2, on the celluar response to ionizing radiation at low dose rates. Int J Radiat Oncol Biol Phys 2000. [DOI: 10.1016/s0360-3016(00)80376-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Clairmont CA, Narayanan L, Sun KW, Glazer PM, Sweasy JB. The Tyr-265-to-Cys mutator mutant of DNA polymerase beta induces a mutator phenotype in mouse LN12 cells. Proc Natl Acad Sci U S A 1999; 96:9580-5. [PMID: 10449735 PMCID: PMC22251 DOI: 10.1073/pnas.96.17.9580] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [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: 11/18/2022] Open
Abstract
DNA polymerase beta functions in both base excision repair and meiosis. Errors committed by polymerase beta during these processes could result in mutations. Using a complementation system, in which rat DNA polymerase beta substitutes for DNA polymerase I of Escherichia coli, we previously isolated a DNA polymerase beta mutant in which Tyr-265 was altered to Cys (Y265C). The Y265C mutant is dominant to wild-type DNA polymerase beta and possesses an intrinsic mutator activity. We now have expressed the wild-type DNA polymerase and the Y265C mutator mutant in mouse LN12 cells, which have endogenous DNA polymerase beta activity. We demonstrate that expression of the Y265C mutator mutant in the LN12 cells results in an 8-fold increase in the spontaneous mutation frequency of lambdacII mutants compared with expression of the wild-type protein. Expression of Y265C results in at least a 40-fold increase in the frequency of deletions of three bases or more and a 7-fold increase in point mutations. Our results suggest that the mutations we observe in vivo result directly from the action of the mutator polymerase. To our knowledge, this is the first demonstration of a mutator phenotype resulting from expression of a DNA polymerase mutator mutant in mammalian cells. This work raises the possibility that variant polymerases may act in a dominant fashion in human cells, leading to genetic instability and carcinogenesis.
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37
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Narayanan L, Chawla Y, Bhalla AK, Sharma M, Dilawari JB. Assessment of malnutrition in alcoholic and non alcoholic cirrhotics. Trop Gastroenterol 1999; 20:120-2. [PMID: 10695418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
OBJECTIVE To study the nutritional status in patients with chronic liver disease using anthropometric techniques. METHODS A total of 60 cirrhotic patients (30 Alcoholic (AC), 30 Non-alcoholic (NAC) and 30 control (CO) subjects were studied. Nutritional status was assessed using anthropometric measurements such as stature, body weight, body mass index, (BMI), skinfold thickness measurements and mid upper arm muscle circumference. Serum protein, serum albumin and globulin were measured. RESULTS The skinfold thicknesses were significantly lower in NAC group of patients. In contrast the AC group of patients showed significantly lower mid upper arm muscle circumference values. Both groups of cirrhotic patients showed significantly lower total serum protein and serum albumin levels. CONCLUSION Body fat is relatively more affected in NAC group of patients and muscle mass is more affected in AC group of patients.
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Affiliation(s)
- L Narayanan
- Postgraduate Institute of Medical Education and Research, Chandigarh, India
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38
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Narayanan L, Moghaddam AP, Taylor AG, Sudberry GL, Fisher JW. Sensitive high-performance liquid chromatography method for the simultaneous determination of low levels of dichloroacetic acid and its metabolites in blood and urine. J Chromatogr B Biomed Sci Appl 1999; 729:271-7. [PMID: 10410952 DOI: 10.1016/s0378-4347(99)00165-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Dichloroacetic acid (DCA) is a contaminant found in treated drinking water due to chlorination. DCA has been shown to be a complete hepatocarcinogen in both mice and rats. In this study we developed a rapid and sensitive high-performance liquid chromatography (HPLC) method to simultaneously detect DCA and its metabolites, oxalic acid, glyoxylic acid and glycolic acid in blood and urine samples of animals sub-chronically administered with DCA (2 g/l) in drinking water. Both urine and plasma samples were treated minimally before HPLC analysis. Separation and detection of DCA and its metabolites were achieved using an anion-exchange column and a conductivity detector. The mobile phase consisted of an initial concentration of 0.01 mM sodium hydroxide in 40% methanol followed by a linear gradient from 0.01 mM to 60 mM sodium hydroxide in 40% methanol for 30 min. The lower detection limit for DCA and each of its three major metabolites was 0.05 microg/ml. DCA and its metabolites gave a linear response range from 0.05 to 100 microg/ml. Plasma DCA was also analyzed by gas chromatography (GC), and the results obtained correlated with those from the HPLC method (correlation coefficient=0.999). While available HPLC techniques offer sensitive procedures to detect either glycolic acid or oxalic acid, the described HPLC method has the unique advantage of determining simultaneously the parent compound (DCA) and its three major metabolites (oxalic acid, glyoxylic acid and glycolic acid) in biological samples, without complex sample preparation.
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Affiliation(s)
- L Narayanan
- GEO-CENTERS, Inc., Wright-Patterson AFB, OH 45433-7400, USA.
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39
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Yao X, Buermeyer AB, Narayanan L, Tran D, Baker SM, Prolla TA, Glazer PM, Liskay RM, Arnheim N. Different mutator phenotypes in Mlh1- versus Pms2-deficient mice. Proc Natl Acad Sci U S A 1999; 96:6850-5. [PMID: 10359802 PMCID: PMC22005 DOI: 10.1073/pnas.96.12.6850] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [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: 11/18/2022] Open
Abstract
Deficiencies in DNA mismatch repair (MMR) result in increased mutation rates and cancer risk in both humans and mice. Mouse strains homozygous for knockouts of either the Pms2 or Mlh1 MMR gene develop cancer but exhibit very different tumor spectra; only Mlh1(-/-) animals develop intestinal tumors. We carried out a detailed study of the microsatellite mutation spectra in each knockout strain. Five mononucleotide repeat tracts at four different chromosomal locations were studied by using single-molecule PCR or an in vivo forward mutation assay. Three dinucleotide repeat loci also were examined. Surprisingly, the mononucleotide repeat mutation frequency in Mlh1(-/-) mice was 2- to 3-fold higher than in Pms2(-/-) animals. The higher mutation frequency in Mlh1(-/-) mice may be a consequence of some residual DNA repair capacity in the Pms2(-/-) animals. Relevant to this idea, we observed that Pms2(-/-) mice exhibit almost normal levels of Mlh1p, whereas Mlh1(-/-) animals lack both Mlh1p and Pms2p. Comparison between Mlh1(-/-) animals and Mlh1(-/-) and Pms2(-/-) double knockout mice revealed little difference in mutator phenotype, suggesting that Mlh1 nullizygosity is sufficient to inactivate MMR completely. The findings may provide a basis for understanding the greater predisposition to intestinal cancer of Mlh1(-/-) mice. Small differences (2- to 3-fold) in mononucleotide repeat mutation rates may have dramatic effects on tumor development, requiring multiple genetic alterations in coding regions. Alternatively, this strain difference in tumor spectra also may be related to the consequences of the absence of Pms2p compared with the absence of both Pms2p and Mlh1p on as yet little understood cellular processes.
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Affiliation(s)
- X Yao
- Molecular Biology Program, University of Southern California, Los Angeles, CA 90089-1340, USA
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40
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Nordholm AF, Rossi J, Ritchie GD, McInturf S, Hulme ME, McCool C, Narayanan L, MacMahon KL, Eggers J, Leahy HF, Wolfe RE. Repeated exposure of rats to JP-4 vapor induces changes in neurobehavioral capacity and 5-HT/5-HIAA levels. J Toxicol Environ Health A 1999; 56:471-499. [PMID: 10201635 DOI: 10.1080/009841099157935] [Citation(s) in RCA: 7] [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] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Thirty-two Sprague-Dawley rats were exposed for 6 h/d for 14 consecutive days to JP-4 jet fuel vapor (2 mg/L) or room air control conditions. Following a 14- or 60-d recovery period, rats completed a battery of 8 tests selected from the Navy Neurobehavioral Toxicity Assessment Battery (NTAB) to evaluate changes in performance capacity. Exposure to JP-4 vapor resulted in significant changes in neurobehavioral capacity on several tests that varied as a function of the duration of the recovery period. Rats were evaluated for major neurotransmitter and metabolite levels in five brain regions and in the blood serum. Levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were shown to be significantly elevated in several brain regions as well as in the blood serum in the vapor-exposed groups. Results of the rat study are compared to previously reported neurobehavioral evaluations of European manufacturing personnel exposed chronically to jet fuel vapor.
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Affiliation(s)
- A F Nordholm
- Naval Health Research Institute Detachment-Toxicology, Wright-Patterson Air Force Base, Ohio, USA
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Glazer P, Fritzell J, Narayanan L. Role of DNA mismatch repair in response to ionizing radiation. Int J Radiat Oncol Biol Phys 1998. [DOI: 10.1016/s0360-3016(98)80160-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Fritzell JA, Narayanan L, Baker SM, Bronner CE, Andrew SE, Prolla TA, Bradley A, Jirik FR, Liskay RM, Glazer PM. Role of DNA mismatch repair in the cytotoxicity of ionizing radiation. Cancer Res 1997; 57:5143-7. [PMID: 9371516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The DNA mismatch repair (MMR) system in mammalian cells not only serves to correct base mispairs and other replication errors, but it also influences the cellular response to certain forms of DNA damage. Cells that are deficient in MMR are relatively resistant to alkylation damage because, in wild-type cells, the MMR system is thought to promote toxicity via futile repair of alkylated mispairs. Conversely, MMR-deficient cells are sensitive to UV light, possibly due to the requirement for MMR factors in transcription-coupled repair of active genes. MMR deficiency has been associated with familial and sporadic carcinomas of the colon and other sites, and so, we sought to determine the influence of MMR status on cellular response to ionizing radiation, an agent commonly used for cancer therapy. Fibroblast cell lines were established from transgenic mice carrying targeted disruptions of one of three MMR genes in mammalian cells: Pms2, Mlh1, or Msh2. In comparison to wild-type cell lines from related mice, the Pms2-, Mlh1-, or Msh2-nullizygous cell lines were found to exhibit higher levels of clonogenic survival following exposure to ionizing radiation. Because ionizing radiation generates a variety of lesions in DNA, the differences in survival may reflect a role for MMR in processing a subset of these lesions, such as damaged bases. These results both identify a new class of DNA-damaging agents whose effects are modulated by the MMR system and may help to elucidate pathways of radiation response in cancer cells.
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Affiliation(s)
- J A Fritzell
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-8040, USA
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44
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Turner BC, Haffty BG, Narayanan L, Yuan J, Havre PA, Gumbs AA, Kaplan L, Burgaud JL, Carter D, Baserga R, Glazer PM. Insulin-like growth factor-I receptor overexpression mediates cellular radioresistance and local breast cancer recurrence after lumpectomy and radiation. Cancer Res 1997; 57:3079-83. [PMID: 9242428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The insulin-like growth factor-I receptor (IGF-IR) plays a critical role in cell growth regulation and transformation. The radiosensitivity of NIH 3T3 fibroblasts overexpressing either wild-type or mutant IGF-IR was examined. High levels of wild-type IGF-IR conferred radioresistance, and mutational analysis revealed that this effect correlated with the transforming capacity but not the mitogenic activity of the receptor. The radioresistant phenotype was reversed when the cells were incubated with antisense oligonucleotides targeted to IGF-IR mRNA, demonstrating that IGF-IR directly influences radioresistance. The clinical significance of these findings was examined in an immunohistochemical analysis of primary breast tumors, revealing that high levels of IGF-IR in tumor samples were highly correlated with ipsilateral breast tumor recurrence (IBTR) following lumpectomy and radiation therapy (P = 0.001). Subgroup analysis revealed that, for early breast tumor relapses (within 4 years of initial breast tumor diagnosis), elevated levels of IGF-IR were strongly associated with IBTR (P = 0.004) but IGF-IR expression was not prognostic for IBTR from breast cancer patients with late relapses (P was not significant). These studies provide evidence for the influence of IGF-IR on cellular radioresistance and response to therapy and raise the possibility that the radiocurability of selected tumors may be improved by pharmaceutical strategies directed toward the IGF-IR.
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Affiliation(s)
- B C Turner
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-8040, USA
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Narayanan L, Fritzell JA, Baker SM, Liskay RM, Glazer PM. Elevated levels of mutation in multiple tissues of mice deficient in the DNA mismatch repair gene Pms2. Proc Natl Acad Sci U S A 1997; 94:3122-7. [PMID: 9096356 PMCID: PMC20332 DOI: 10.1073/pnas.94.7.3122] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/1996] [Accepted: 01/16/1997] [Indexed: 02/04/2023] Open
Abstract
The Pms2 gene has been implicated in hereditary colon cancer and is one of several mammalian homologs of the Escherichia coli mutL DNA mismatch repair gene. To determine the effect of Pms2 inactivation on genomic integrity in vivo, hybrid transgenic mice were constructed that carry targeted disruptions at the Pms2 loci along with a chromosomally integrated mutation reporter gene. In the absence of any mutagenic treatment, mice nullizygous for Pms2 showed a 100-fold elevation in mutation frequency in all tissues examined compared with both wild-type and heterozygous litter mates. The mutation pattern in the nullizygotes was notable for frequent 1-bp deletions and insertions within mononucleotide repeat sequences, consistent with an essential role for PMS2 in the repair of replication slippage errors. Further, the results demonstrate that high rates of mutagenesis in multiple tissues are compatible with normal development and life and are not necessarily associated with accelerated aging. Also, the finding of genetic instability in all tissues tested contrasts with the limited tissue distribution of cancers in the animals, raising important questions regarding the role of mutagenesis in carcinogenesis.
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Affiliation(s)
- L Narayanan
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520-8040, USA
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Weitzhandler M, Pohl C, Rohrer J, Narayanan L, Slingsby R, Avdalovic N. Eliminating amino acid and peptide interference in high-performance anion-exchange pulsed amperometric detection glycoprotein monosaccharide analysis. Anal Biochem 1996; 241:128-34. [PMID: 8921174 DOI: 10.1006/abio.1996.0386] [Citation(s) in RCA: 31] [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: 02/03/2023]
Abstract
The monosaccharide content of a glycoprotein is often determined by acid hydrolysis at elevated temperature and subsequent high pH chromatography of the released, underivatized monosaccharides on pellicular anion-exchange resin (HPAE) using pulsed amperometric detection (PAD). We have found that for glycoproteins with low levels of glycosylation, monosaccharide quantitation can be compromised by amino acids fouling the working electrode surface. Specifically, lysine elutes on the CarboPac PA1 column just prior to galactosamine, whereas remaining amino acids and most peptides elute after the monosaccharides and do not interfere with monosaccharide quantification. A direct comparison of PAD vs Abs215 detection of lysine using the CarboPac PA1 column as the separator reveals that lysine does not cleanly come off the working electrode. The monosaccharide response inhibition caused by lysine could be corrected by the posthydrolysis addition of a rhamnose internal standard and the determination of "correction factors." We have developed a guard column with an altered selectivity for amino acids which, when used with a new separator, causes lysine to elute after the monosaccharides and also causes hydrophobic amino acids to elute further after the monosaccharides. Together the new separator and guard columns solve the lysine fouling problem, reduce sample-related baseline noise, and reduce the magnitude of correction factors.
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Weitzhandler M, Slingsby R, Jagodzinski J, Pohl C, Narayanan L, Avdalovic N. Eliminating monosaccharide peak tailing in high pH anion-exchange chromatography with pulsed amperometric detection. Anal Biochem 1996; 241:135-6. [PMID: 8921175 DOI: 10.1006/abio.1996.0387] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Reo NV, Narayanan L, Kling KB, Adinehzadeh M. Perfluorodecanoic acid, a peroxisome proliferator, activates phospholipase C, inhibits CTP:phosphocholine cytidylyltransferase, and elevates diacylglycerol in rat liver. Toxicol Lett 1996; 86:1-11. [PMID: 8685914 DOI: 10.1016/0378-4274(96)03653-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) are peroxisome proliferators that cause hepatotoxicity in rodents. This study shows that PFDA activates liver phospholipase C (PLC) and inhibits CTP:phosphocholine cytidylyltransferase (CT). PLC cytosolic and microsomal activities were increased 1.4- and 1.7-fold, respectively. CT activates were decreased to 58% (cytosol) and 36% (microsome) of control values. PFDA also caused a threefold increase in liver diacylglycerol (DAG) concentration. PFOA had no effect on the enzyme activities or DAG concentration. Together with previous results, these data suggest that PFDA activates a phosphatidylcholine-specific PLC causing an increase in liver phosphocholine and DAG. These effects are discussed in relation to cellular signalling processes that may provide a mechanism for PFDA-induced hepatotoxicity.
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Affiliation(s)
- N V Reo
- Department of Biochemistry and Molecular Biology, Wright State University, Cox Institute, Dayton, Ohio 45429, USA
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Levine EL, Spector PE, Menon S, Narayanan L. Validity Generalization for Cognitive, Psychomotor, and perceptual Tests for Craft Jobs in the Utility Industry. Human Performance 1996. [DOI: 10.1207/s15327043hup0901_1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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