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Mohan S, Gandhimathi R. Solid waste characterisation and the assessment of the effect of dumping site leachate on groundwater quality: a case study. ACTA ACUST UNITED AC 2009. [DOI: 10.1504/ijewm.2009.024700] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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252
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Behboodi E, Mohan S, Rodriguez-Sosa JR, Li Y, Megee S, Dobrinski I. Enrichment of porcine spermatogonia by differential culture. SOCIETY OF REPRODUCTION AND FERTILITY SUPPLEMENT 2009; 66:209-210. [PMID: 19848288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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253
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Lakshmanan P, Selvaraj P, Mohan S. Efficacy of different methods for the control of Panama disease. ACTA ACUST UNITED AC 2008. [DOI: 10.1080/09670878709371187] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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254
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Kokila M, Puttaraja, Anil Kumar G, Chandra Kumar K, Mohan S, Saravanan J, Kulkarni M. A study on the effect of substitutions and intermolecular interactions in thiophene 3-carboxamides. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308087345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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255
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Anil Kumar G, Kokila M, Puttaraja, Mohan S, Saravanan J. Crystal and molecular structure of biologically active thiophene 3-furfuryl carboxamide derivative. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308087333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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256
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Chandra Kumar K, Kokila M, Puttaraja, Mohan S, Saravanan J, Kulkarni M. Crystal structure of 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308087321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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257
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Govoni KE, Donahue LR, Marden C, Mohan S. Complex genetic regulation of bone mineral density and insulin-like growth factor-I in C57BL/6J-Chr #A/J/NaJ chromosome substitution strains. Physiol Genomics 2008; 35:159-64. [PMID: 18682576 DOI: 10.1152/physiolgenomics.90203.2008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Low bone mineral density (BMD) is a phenotype associated with osteoporosis and increased risk of fracture. Since 60-80% of variation in BMD is associated with genetic factors, we used the novel approach of chromosome substitution strains (CSS) to identify chromosomes that harbor genes that regulate BMD. Specifically, we evaluated 24 wk old C57BL/6J-Chr #(A/J)/NaJ CSS (n = 7 to 18) in which each chromosome in the host C57BL/6J strain is replaced by a corresponding chromosome from the donor A/J strain (19 autosomes, X, Y). We determined several A/J chromosomes contribute to body weight (BW), percent body fat (BF), whole body areal BMD (aBMD), and serum insulin-like growth factor (IGF)-I in both a positive and negative manner when compared with C57BL/6J. Specifically, C57BL/6J-Chr 5(A/J)/NaJ (B.A-5) (males) and B.A-13 (females) contributed to increased BW, whereas B.A-3, 4, 8, 9, 12, and 18 (males) and B.A-3, 4, and 11 (females) contributed to reduced BW. B.A-5 (males) and B.A-13 (females) contributed to increased BF, whereas B.A-12 (males) and B.A-3, 4, 10, and 11 (females) contributed to reduced BF. B.A-14 (females) contributed to increased aBMD and B.A-1, 2, 6, 9, 10, and 18 (males) and B.A-8, 9, and 10 (females) contributed to reduced aBMD. To determine if similar chromosomes regulate aBMD and IGF-I, we determined serum concentrations of IGF-I. B.A-14 and Y (males) and B.A-6 (females) contributed to increased IGF-I and male B.A-3 and female B.A-8 contributed to reduced IGF-I. Overall, we identified several sex-dependent and -independent chromosomes that regulate aBMD and IGF-I in adult mice.
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Mohan S, Bustamam A, Ibrahim S, S. Al-Zuba A, Aspollah M. Anticancerous Effect of Typhonium flagelliforme on Human T4-Lymphoblastoid Cell Line CEM-ss. ACTA ACUST UNITED AC 2008. [DOI: 10.3923/jpt.2008.449.456] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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259
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Lin AW, Trejos AL, Mohan S, Bassan H, Kashigar A, Patel RV, Malthaner RA. Electromagnetic navigation improves minimally invasive robot-assisted lung brachytherapy. ACTA ACUST UNITED AC 2008; 13:114-23. [PMID: 18317960 DOI: 10.3109/10929080801969725] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Recent advances in minimally invasive thoracic surgery have renewed an interest in the role of interstitial brachytherapy for lung cancer. Our previous work has demonstrated that a minimally invasive robot-assisted (MIRA) lung brachytherapy system produced results that were equal to or better than those obtained with standard video-assisted thoracic surgery (VATS) and comparable to results with open surgery. The purpose of this project was to evaluate the performance of an integrated system for MIRA lung brachytherapy that incorporated modified electromagnetic navigation and ultrasound image guidance with robotic assistance. METHODS The experimental test-bed consisted of a VATS box, ZEUS and AESOP surgical robotic arms, a seed injector, an ultrasound machine, video monitors, a computer, and an endoscope. Our previous custom-designed electromagnetic navigational software and the robotic controller were modified and incorporated into the MIRA III system to become the next-generation MIRA IV. Inactive brachytherapy seeds were injected as close as possible to a small metal ball target embedded in an opaque agar cube. The completion time, the number of attempts, and the accuracy of seed deployment were compared for manual placement, standard VATS, MIRA III, and the new MIRA IV system. RESULTS The MIRA IV system significantly reduced the median procedure time by 61% (104 s to 41 s), tissue trauma by 75% (4 attempts to 1 attempt), and mean seed placement error by 64% (2.5 mm to 0.9 mm) when compared to a standard VATS. MIRA IV also reduced the mean procedure time by 48% (85 s to 44 s) and the seed placement error by 68% (2.8 mm to 0.9 mm) compared to the MIRA III system. CONCLUSIONS A modified integrated system for performing minimally invasive robot-assisted lung brachytherapy was developed that incorporated electromagnetic navigation and an improved robotic controller. The MIRA IV system performed significantly better than standard VATS and better than MIRA III.
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Anilkumar GN, Kokila MK, Puttaraja, Mohan S, Saravanan J. 6-Methyl- N-(4-methoxyphenyl)-2-[( E)-(4-methylphenyl)methyleneamino]-4,5,6,7-tetrahydrothieno[2,3- c]pyridine-3-carboxamide. Acta Crystallogr Sect E Struct Rep Online 2008; 64:o1258. [PMID: 21202892 PMCID: PMC2961643 DOI: 10.1107/s1600536808017236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Accepted: 06/08/2008] [Indexed: 11/10/2022]
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261
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Chadwick R, Bu L, Yu H, Hu Y, Sachdev R, Tan Q, Wergedal J, Mohan S, Baylink D. 038
Digit Tip Regeneration and Global Gene Expression Profiling in the MRL SuperHealer Mouse. Wound Repair Regen 2008. [DOI: 10.1111/j.1067-1927.2005.130215al.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Natarajan M, Mohan S, Konopinski R, Otto RA, Herman TS. Induced telomerase activity in primary aortic endothelial cells by low-LET gamma-radiation is mediated through NF-kappaB activation. Br J Radiol 2008; 81:711-20. [PMID: 18541630 DOI: 10.1259/bjr/57867919] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Our objective was to understand the mechanism through which cells that initially survive irradiation could acquire survival advantage. In this study, we show evidence that low-linear energy transfer gamma-radiation can induce telomerase enzyme activity in primary aortic endothelial cells, and that an upstream regulator, nuclear factor kappa B (NF-kappaB), controls this activation. Telomeric repeat amplification protocol (TRAP) assay showed that cells exposed to a dose of 2 Gy induce telomerase activity. Subsequent analysis revealed that radiation-induced telomeric activity is regulated at the transcriptional level by triggering activation of the promoter of the telomerase catalytic subunit, telomerase reverse transcriptase (TERT). A mechanistic study revealed that NF-kappaB becomes functionally activated upon radiation exposure and mediates the upregulation of telomerase activity by binding to the kappaB-binding region in the promoter region of the TERT gene. More significantly, elimination of the NF-small ka, CyrillicB recognition site on the telomerase promoter or inhibition of NF-small ka, CyrillicB by ectopically expressing the inhibitor protein IkappaBalpha mutant (Ismall ka, CyrillicBalpha(S32A/S36A))) compromises radiation-induced telomerase promoter activation. Consistent with the notion that NF-kappaB mediates gamma-ray-induced telomerase responses, TRAP assay revealed that ectopically expressed IkappaBalpha(S32A/S36A)) also attenuated telomerase enzyme activity. These findings indicate that NF-kappaB activation following ionizing radiation exposure may elicit a survival advantage by upregulating and maintaining telomerase activity.
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Wittrant Y, Gorin Y, Woodruff K, Horn D, Abboud HE, Mohan S, Abboud-Werner SL. High d(+)glucose concentration inhibits RANKL-induced osteoclastogenesis. Bone 2008; 42:1122-30. [PMID: 18378205 PMCID: PMC2696157 DOI: 10.1016/j.bone.2008.02.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 02/01/2008] [Accepted: 02/06/2008] [Indexed: 12/28/2022]
Abstract
Diabetes is a chronic disease associated with hyperglycemia and altered bone metabolism that may lead to complications including osteopenia, increased risk of fracture and osteoporosis. Hyperglycemia has been implicated in the pathogenesis of diabetic bone disease; however, the biologic effect of glucose on osteoclastogenesis is unclear. In the present study, we examined the effect of high d(+)glucose (d-Glc) and l(-)glucose (l-Glc; osmotic control) on RANKL-induced osteoclastogenesis using RAW264.7 cells and Bone Marrow Macrophages (BMM) as models. Cells were exposed to sustained high glucose levels to mimic diabetic conditions. Osteoclast formation was analyzed using tartrate resistant acid phosphatase (TRACP) assay, expression of calcitonin receptor (CTR) and cathepsin K mRNAs, and cultures were examined for reactive oxygen species (ROS) using dichlorodihydrofluorescein diacetate (DCF-DA) fluorescence, caspase-3 and Nuclear Factor kappaB (NF-kappaB) activity. Cellular function was assessed using a migration assay. Results show, for the first time, that high d-Glc inhibits osteoclast formation, ROS production, caspase-3 activity and migration in response to RANKL through a metabolic pathway. Our findings also suggest that high d-Glc may alter RANKL-induced osteoclast formation by inhibiting redox-sensitive NF-kappaB activity through an anti-oxidative mechanism. This study increases our understanding of the role of glucose in diabetes-associated bone disease. Our data suggest that high glucose levels may alter bone turnover by decreasing osteoclast differentiation and function in diabetes and provide new insight into the biologic effects of glucose on osteoclastogenesis.
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Mohan S, Sreelakshmi G. Fixed bed column study for heavy metal removal using phosphate treated rice husk. JOURNAL OF HAZARDOUS MATERIALS 2008; 153:75-82. [PMID: 17897779 DOI: 10.1016/j.jhazmat.2007.08.021] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2006] [Revised: 08/07/2007] [Accepted: 08/08/2007] [Indexed: 05/17/2023]
Abstract
This paper reports the results of the study on the performance of low-cost adsorbent such as raw rice husk (RRH) and phosphate treated rice husk (PRH) in removing the heavy metals such as lead, copper, zinc and manganese. The adsorbent materials adopted were found to be an efficient media for the removal of heavy metals in continuous mode using fixed bed column. The column studies were conducted with 10 mg/l of individual and combined metal solution with a flow rate of 20 ml/min with different bed depths such as 10, 20 and 30 cm. The breakthrough time was also found to increase from 1.3 to 3.5 h for Pb(II), 4.0 to 9.0 h for Cu(II), 12.5 to 25.4h for Zn(II) and 3.0 to 11.3 h for Mn(II) with increase in bed height from 10 to 30 cm for PRH. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. were calculated. It is found that the adsorption capacity and adsorption rate constant were increased and the minimum column bed depth required was reduced when the rice husk is treated with phosphate, when compared with that of RRH.
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Mohan S, Cheng J, Pogue V, Park C. 174: Association of HCO3 and Phosphate with PTH Levels (iPTH, CAP, CIP and tPTH) In a Hemodialysis Cohort. Am J Kidney Dis 2008. [DOI: 10.1053/j.ajkd.2008.02.183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Mohan S, Cheng J, Pogue V, Park C. 175: Ethnic Differences in PTH and Mineral Metabolism in Patients Receiving Chronic Hemodialysis. Am J Kidney Dis 2008. [DOI: 10.1053/j.ajkd.2008.02.184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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267
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Mujtaba M, Madhrira M, Agarwala R, Mohan S, Park C, Anderson H, Pogue V, Cheng J. 178: Management and Toxicokinetics of Metformin Associated Lactic Acidosis (MALA) By Continuous Venovenous Hemodiafiltration (CVVHDF). Am J Kidney Dis 2008. [DOI: 10.1053/j.ajkd.2008.02.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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268
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Verma A, Mohan S, Kathuria M, Baijal SS. Esophageal bronchus: case report and review of the literature. Acta Radiol 2008; 49:138-41. [PMID: 18309539 DOI: 10.1080/02841850701673391] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Communicating bronchopulmonary foregut malformation (CBPFM) is a rare abnormality that is characterized by persistent communication between the bronchial tree and the gastrointestinal tract. We report a case of CBPFM in a young girl, with a description of the imaging and surgical details and a short review of the relevant literature.
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Talwar N, Mohan S, Ravi B, Andley M, Kumar A. Lithium-induced enlargement of a lingual thyroid. Singapore Med J 2008; 49:254-255. [PMID: 18363010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Lingual thyroid is a rare developmental anomaly. It is the result of failure of the thyroid to descend from the foramen caecum to its prelaryngeal site. Lithium is a known goitrogen, but has never been reported to cause symptomatic enlargement of the lingual thyroid. We describe a 40-year-old woman, who presented with a foreign body sensation and progressive dysphagia caused by an ectopic lingual thyroid tissue measuring 4 cm x 3 cm x 3.5 cm. She had been taking lithium for treatment of bipolar disorder and had hypothyroidism. Her symptoms were relieved after excision of the ectopic thyroid tissue.
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Mohan S, Sunny N. Study on biomethonization of waste water from jam industries. BIORESOURCE TECHNOLOGY 2008; 99:210-3. [PMID: 17275291 DOI: 10.1016/j.biortech.2006.11.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 11/25/2006] [Accepted: 11/29/2006] [Indexed: 05/13/2023]
Abstract
Anaerobic digestion of wastewater from jam industries was studied in a continuous reactor with different organic loading rates (OLR) and the optimum organic loading rate was 6.5 kg COD/m(3)/day when it was operated with three days HRT. The biodegradability of wastewater in batch experiments was about 90%. The removal efficiency of total COD and soluble COD were found to 82% and 85%, respectively. The specific methane production was 0.28 m(3)/kg of COD removed/day.
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Mohan S, Chest V, Chadwick RB, Wergedal JE, Srivastava AK. Chemical mutagenesis induced two high bone density mouse mutants map to a concordant distal chromosome 4 locus. Bone 2007; 41:860-8. [PMID: 17884746 DOI: 10.1016/j.bone.2007.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2007] [Revised: 07/18/2007] [Accepted: 07/19/2007] [Indexed: 11/28/2022]
Abstract
Phenotype-driven mutagenesis approach in the mouse holds much promise as a method for revealing gene function. Earlier, we have described an N-ethyl-N-nitrosourea (ENU) mutagenesis screen to create genome-wide dominant mutations in the mouse model. Using this approach, we describe identification of two high bone density mutants in C57BL/6J (B6) background. The mutants, named as 12184 and 12137, have been bred more than five generations with wild-type B6 mice, each producing >200 backcross progeny. The average total body areal bone mineral density (aBMD) was 13-17% higher in backcrossed progeny from both mutant lines between 6 and 10 weeks of age, as compared to wild-type (WT) B6 mice (n=60-107). At 3 weeks of age the aBMD of mutant progeny was not significantly affected as compared to WT B6 mice. Data from 10- and 16-week old progeny show that increased aBMD was mainly related to a 14-20% higher bone mineral content, whereas bone size was marginally increased. In addition, the average volumetric BMD (vBMD) was 5-15% higher at the midshaft tibia or femur, as compared to WT mice. Histomorphometric analysis revealed that bone resorption was 23-34% reduced in both mutant mice. Consistent with histomorphometry data, the mRNA expression of genes that regulate osteoclast differentiation and survival were altered in the 12137 mutant mice. To determine the chromosomal location of the ENU mutation, we intercrossed both mutant lines with C3H/HeJ (C3H) mice to generate B6C3H F2 mice (n=164 for line 12137 and n=137 F2 for line 12184). Interval mapping using 60 microsatellite markers and aBMD phenotype revealed only one significant or suggestive linkage on chromosome 4. Since body weight was significantly higher in mutant lines, we also used body weight as additive and interactive covariate for interval mapping; both analyses showed higher LOD scores for both 12137 and 12184 mutants without affecting the chromosomal location. The large phenotype in the mutant mice compared to generally observed QTL effects (<5%) would increase the probability of identifying the mutant gene.
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Natarajan M, Gibbons CF, Mohan S, Moore S, Kadhim MA. Oxidative stress signalling: a potential mediator of tumour necrosis factor alpha-induced genomic instability in primary vascular endothelial cells. Br J Radiol 2007; 80 Spec No 1:S13-22. [PMID: 17704321 DOI: 10.1259/bjr/15316848] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Studying the potential role of tumour necrosis factor (TNF)alpha in the initiation of genomic instability is necessary to understand whether TNFalpha can serve as a signalling mediator of radiation-induced genomic instability in non-irradiated bystander cells. In this study, we examined whether TNFalpha could initiate processes through oxidative stress signalling that lead to DNA damage and genomic instability in primary vascular endothelium. In these cells, low linear energy transfer (LET) radiation (0.1-2 Gy) induced the secretion of TNFalpha into the culture medium. When added ectopically, TNFalpha at concentrations ranging from 0.1 ng ml(-1) to 10 ng ml(-1) increased (twofold to threefold) intracellular oxidative stress. Next, to examine whether TNFalpha induces genetic damage, cells were treated with TNFalpha for 5 h and analysed immediately using the single cell gel electrophoresis assay or after 3 days, 12 days and 20 days using solid stain chromosomal analysis. Cells exposed to 0.1 Gy, 1 Gy or 2 Gy or treated with 100 microM H2O2 were used as positive controls. The results showed that TNFalpha as low as 0.1 ng ml(-1) could initiate increased DNA damage compared with untreated controls. When examined in the progeny cells after several generations, the chromosomal instability appeared to be carried over even after day 12 and day 20. The increased genetic damage is inhibited in cells that are pre-incubated with the antioxidant enzyme catalase, the antioxidant N-acetyl-L-cysteine or the metal chelator pyrrolidine dithiocarbamate. These results clearly indicate that TNFalpha at concentrations at which no cytotoxicity is observed could induce genetic damage through free radical generation, which could, in turn, lead to the delayed events associated with genomic instability.
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Baylink D, Lau KHW, Mohan S. The role of IGF system in the rise and fall in bone density with age. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2007; 7:304-305. [PMID: 18094484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Edderkaoui B, Baylink DJ, Beamer WG, Shultz KL, Wergedal JE, Mohan S. Genetic regulation of femoral bone mineral density: complexity of sex effect in chromosome 1 revealed by congenic sublines of mice. Bone 2007; 41:340-5. [PMID: 17618849 DOI: 10.1016/j.bone.2007.05.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 05/22/2007] [Accepted: 05/31/2007] [Indexed: 11/17/2022]
Abstract
The findings that sex-specific effects on femoral structure and peak bone mineral density (BMD) are linked to quantitative trait loci (QTL) provide evidence for the involvement of specific genes that contribute to gender variation in skeletal phenotype. Based on previous findings that the BMD QTL in chromosome 1 (Chr 1) exerts a sex-specific effect on femoral structure, we predicted that congenic sublines of mice that carry one or more of the Chr 1 BMD loci would exhibit gender difference in the volumetric BMD (vBMD) phenotype. To test this hypothesis, we compared skeletal parameters of male and female of five C57BL/6J (B6).CAST/EiJ (CAST)-1 congenic sublines of mice that carry overlapping CAST chromosomal segments from the vBMD loci in Chr 1. Femur vBMD measurements were performed by the peripheral quantitative computed tomography in male and female mice at 16 weeks of age. The skeletal phenotype of the C175-185 and C178-185 congenic sublines of mice provided evidence for the presence of the BMD1-4 locus at 178-180 Mb from the centromere. This QTL affects femur vBMD only in female mice. In contrast, CAST chromosomal region carrying BMD1-1 locus increased femur vBMD both in male and female mice. Furthermore, a gender specific effect on BMD of femur mid-shaft region (mid-BMD) was identified at 168-176 Mb in Chr 1 (F=16.49, P=0.0002), while no significant effect was found on total femur BMD (F=2.67, P=0.11). Moreover, this study allowed us to locate a body weight QTL at 168-172 Mb of Chr 1, the effect of this locus was altered in female mice that carry CAST chromosomal segment 168-176 Mb of Chr 1. Based on this study, we conclude that Chr 1 carries at least two vBMD gender-dependent loci; one genetic locus at 178-180 Mb (BMD1-4 locus) which affects both mid-shaft and total femur vBMD in female mice only, and another gender-dependent locus at 168-176 Mb (BMD1-2 locus) which affects femur mid-shaft vBMD in female but not male mice.
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Saxon LK, Robling AG, Castillo AB, Mohan S, Turner CH. The skeletal responsiveness to mechanical loading is enhanced in mice with a null mutation in estrogen receptor-beta. Am J Physiol Endocrinol Metab 2007; 293:E484-91. [PMID: 17535856 DOI: 10.1152/ajpendo.00189.2007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanical loading caused by physical activity can stimulate bone formation and strengthen the skeleton. Estrogen receptors (ERs) play some role in the signaling cascade that is initiated in bone cells after a mechanical load is applied. We hypothesized that one of the ERs, ER-beta, influences the responsiveness of bone to mechanical loads. To test our hypothesis, 16-wk-old male and female mice with null mutations in ER-beta (ER-beta(-/-)) had their right forelimbs subjected to short daily loading bouts. The loading technique used has been shown to increase bone formation in the ulna. Each loading bout consisted of 60 compressive loads within 30 s applied daily for 3 consecutive days. Bone formation was measured by first giving standard fluorochrome bone labels 1 and 6 days after loading and using quantitative histomorphometry to assess bone sections from the midshaft of the ulna. The left nonloaded ulna served as an internal control for the effects of loading. Mechanical loading increased bone formation rate at the periosteal bone surface of the mid-ulna in both ER-beta(-/-) and wild-type (WT) mice. The ulnar responsiveness to loading was similar in male ER-beta(-/-) vs. WT mice, but for female mice bone formation was stimulated more effectively in ER-beta(-/-) mice (P < 0.001). We conclude that estrogen signaling through ER-beta suppresses the mechanical loading response on the periosteal surface of long bones.
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