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Khanra K, Panda K, Mitra AK, Sarkar R, Bhattacharya C, Bhattacharya N. Exon 8-9 mutations of DNA polymerase β in ovarian carcinoma patients from Haldia, India. Asian Pac J Cancer Prev 2013; 13:4183-6. [PMID: 23098424 DOI: 10.7314/apjcp.2012.13.8.4183] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ovarian cancer is the number one killer among all the gynecological cancers. We undertook association study to identify potential alterations in the genomic DNA of a DNA repair gene, DNA polymerase beta (polβ), involved in base excision repair (BER), in ovarian carcinomas of patients from Haldia, India. Mutations, splice variants have been reported earlier in different tumors other than ovarian tumors. AIM In this study we explored the possibility of association of any mutation of pol beta (Exon 8) with prognosis in 152 ovarian cancer samples. RESULTS Alteration in the exon 8 region (Exon 8:468, AgC; 15.1%) was noted among fifty seven polymorphism positive samples. Alteration in the intervening sequence 8 (IVS8, -25, AgC; 3.9%) was also noted. All alterations are heterozygous in nature. CONCLUSIONS We found no significant association among the samples from serous type, stage IV, and the polβ mutations (P ≤ 0.01). Only a slight tendency of association was evident between IVS8, -25, A to C; and stage III. Further analysis with a larger number of samples is needed.
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Jwala J, Boddu SHS, Paturi DK, Shah S, Smith SB, Pal D, Mitra AK. Functional characterization of folate transport proteins in Staten's Seruminstitut rabbit corneal epithelial cell line. Curr Eye Res 2011; 36:404-16. [PMID: 21501073 DOI: 10.3109/02713683.2011.566411] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE The overall objective of this study was to investigate and characterize the expression of folate transport proteins in Staten's Seruminstitut rabbit corneal (SIRC) epithelial cell line. METHODS [(3)H]Folic acid uptake was studied with respect to time, pH, temperature, sodium, and chloride ion dependency. Inhibition studies were conducted with structural analogs, vitamins, and metabolic inhibitors. [(3)H]Folic acid uptake was also determined with varying concentrations of cold folic acid. Uptake kinetics was studied in the presence of various modulators of intracellular regulatory pathways, protein kinases A and C (PKA and PKC), protein tyrosine kinase (PTK), and calcium-calmodulin modulators. Ex vivo corneal permeability studies were carried out with [(3)H]folic acid in the presence and absence of 1 mM cold folic acid. RESULTS Linear increase in [(3)H]folic acid uptake was observed over 30 min. The process followed saturation kinetics with apparent K(m) of 14.2 ± 0.2 nM, V(max) of (1.5 ± 0.1)*10(-5) micro.moles/min/mg protein, and K(d) of (2.1 ± 0.2)*10(-6) min(-1). The uptake process was found to be dependent on pH, sodium ions, chloride ions, temperature, and energy. Uptake was inhibited in the presence of structural analogs (cold folic acid, methyltetrahydro folate, and methotrexate), but structurally unrelated vitamins did not show any effect. Membrane transport inhibitors SITS, DIDS, probenecid and endocytic inhibitor, colchicine significantly inhibited the [(3)H]folic acid uptake indicating the involvement of receptor/transporter mediated process. PKA, PTK, and Ca(2+)/calmodulin pathways significantly regulate the process. RT-PCR and Western blot analysis confirmed the presence of folate receptor-α (FR-alpha) and proton-coupled folate transporter (PCFT). Permeability of [(3)H]folic acid across the rabbit cornea was (1.48 ± 0.13)*10(-05) cm/sec, and in the presence of cold folic acid it was (1.08 ± 0.10)*10(-05) cm/sec. CONCLUSIONS This work demonstrated the functional and molecular presence of FR-alpha and PCFT in SIRC epithelial cell line.
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Mitra AK, Singh SV, Garg VK, Sharma M, Chaturvedi R, Rath SK. Protective association exhibited by the single nucleotide polymorphism (SNP) rs1052133 in the gene human 8-oxoguanine DNA glycosylase (hOGG1) with the risk of squamous cell carcinomas of the head & neck (SCCHN) among north Indians. Indian J Med Res 2011; 133:605-12. [PMID: 21727658 PMCID: PMC3135987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND & OBJECTIVES Imbalances in compactly regulated DNA repair pathways in the form of single nucleotide polymorphisms (SNPs) within vital DNA repair genes may result in insufficient DNA repair and increase in DNA breaks thus rendering the human system vulnerable to the debilitatory effects of grave diseases like cancers. The present study involves investigation of association of the non-synonymous SNP rs1052133 (C8069G/Ser326Cys) located in the exonic region of the gene human 8-oxoguanine DNA glycosylase (hOGG1) with the risk of squamous cell carcinomas of the head and neck (SCCHN). METHODS Case-control based genetic association study was performed among 575 (250 SCCHN cases and 325 normal healthy controls) sub-population cluster-matched (Indo-Europeans linguistic subgroup + Caucasoid morphological subtype) samples from the north Indian States of Uttar Pradesh and Uttarakhand using polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing analysis. RESULTS Our results demonstrated statistically significant protective association for the heterozygous CG [Odds Ratio (OR) 0.6587, 95% Confidence Interval (CI) 0.4615 to 0.9402, P=0.0238], homozygous mutant GG (OR 0.2570, 95% CI 0.1070 to 0.6175, P=0.0013) and combined mutant CG + GG (OR 0.6057, 95% CI 0.4272 to 0.8586, P=0.0059) genotypes. INTERPRETATION & CONCLUSIONS The results indicate that the polymorphism rs1052133 is strongly associated with SCCHN susceptibility and the mutant (G) allele might be a protective factor for SCCHN among north Indian subpopulations.
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Talukdar K, Mitra AK. Effect of high temperature and the presence of stone-wales defects on the mechanical behavior of a single wall carbon nanotube under tension and compression. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2011; 11:4824-4829. [PMID: 21770110 DOI: 10.1166/jnn.2011.4188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
On the basis of molecular dynamics simulation, a zigzag (7, 0) SWCNT is examined under axial tension and compression to observe its mechanical behavior and fracture pattern in the absence and presence of Stone-Wales (SW) defects coupled with the variation of temperature. A defect-free tube is subjected to tensile or compressive stresses at different temperatures. Then SW defects are introduced into it and stress is applied with the increase of temperature. The defective and defect-free tubes show different fracture patterns with increasing temperature showing significant changes in their mechanical properties. Compression of the tube also reveals interesting changes in its buckling behavior with variation of temperature and inclusion of defects.
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Abstract
The aetiology of obesity is multifactorial. An understanding of the contributions of various causal factors is essential for the proper management of obesity. Although it is primarily thought of as a condition brought on by lifestyle choices, recent evidence shows there is a link between obesity and viral infections. Numerous animal models have documented an increased body weight and a number of physiologic changes, including increased insulin sensitivity, increased glucose uptake and decreased leptin secretion that contribute to an increase in body fat in adenovirus-36 infection. Other viral agents associated with increasing obesity in animals included canine distemper virus, rous-associated virus 7, scrapie, Borna disease virus, SMAM-1 and other adenoviruses. This review attempted to determine if viral infection is a possible cause of obesity. Also, this paper discussed mechanisms by which viruses might produce obesity. Based on the evidence presented in this paper, it can be concluded that a link between obesity and viral infections cannot be ruled out. Further epidemiologic studies are needed to establish a causal link between the two, and determine if these results can be used in future management and prevention of obesity.
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Bhat PS, Mitra AK, Anand A. Case of Toluene Abuse. Med J Armed Forces India 2010; 66:88-9. [PMID: 27365717 DOI: 10.1016/s0377-1237(10)80111-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 08/28/2009] [Indexed: 10/18/2022] Open
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Chattopadhyay M, Kumbhakar P, Tiwary CS, Mitra AK, Chatterjee U, Kobayashi T. Three-photon-induced four-photon absorption and nonlinear refraction in ZnO quantum dots. OPTICS LETTERS 2009; 34:3644-3646. [PMID: 19953148 DOI: 10.1364/ol.34.003644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Three-photon-induced four-photon absorption via excited-state absorption and self-defocusing nonlinear refraction are reported for the first time, to our knowledge, in ZnO quantum dots with average sizes of 2.0+/-0.1 nm with 1064 nm radiation from a Q-switched Nd:YAG laser at a peak intensity of 2.5 GW/cm(2). By employing the three-level two-step model, the experimental results can be explained quite satisfactorily.
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Bhat PS, Mitra AK, Anand A. Journal Scan. Med J Armed Forces India 2009. [DOI: 10.1016/s0377-1237(09)80040-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Mitra AK, Gao L, Zucker IH. Angiotensin II induces upregulation of AT1 receptors via the sequential activation of transcription factors NFkB, Elk‐1 and AP‐1 in Cath.a cells. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.609.15] [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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Mitra AK, Chandrasekaran R. Conformational analysis of cyclo (L-cystine). INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 2009; 10:235-9. [PMID: 914426 DOI: 10.1111/j.1399-3011.1977.tb01739.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Conformational analysis of cyclo(L-cystine) shows that the diketopiperazine ring has to exist only in the boat form. With this geometry, the molecule can adopt two distinct forms differing mainly in the chirality of the disulphide bridge. In both the P- and M-models, corresponding to dihedral angles of nearly +90 degrees and -90 degrees respectively about the S-S- bond, the molecule displays an approximate two-fold symmetry. According to our semi-empirical energy calculations, the minimum energy of the M-model is --9.2 kcal/mol, only 0.3 kcal/mol lower than that of the P-model. Because the difference between the two minima is so small, neither form is clearly superior to the other. However, the number of low energy conformations of the M-model in the allowed conformational space is significantly larger than that of the P-model by a ratio of 3 to 1, and therefore the former is likely to be thermodynamically favoured.
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Mitra AK, Singh N, Singh A, Garg VK, Agarwal A, Sharma M, Chaturvedi R, Rath SK. Association of polymorphisms in base excision repair genes with the risk of breast cancer: a case-control study in North Indian women. Oncol Res 2008; 17:127-35. [PMID: 18669164 DOI: 10.3727/096504008785055567] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Inheritance of common genetic variants at one or more base excision repair (BER) genes may result in a reduced DNA repair capacity and in an increased risk of cancers like breast cancer. The present case-control study with 390 north Indian women (155 breast cancer cases and 235 controls) was aimed to investigate the association of seven nonsynonymous BER gene polymorphisms viz. rs1130409/T1865G (APEX1), rs1799782/T22142C (XRCC1), rs25487/G23990A (XRCC1), rs4989588/T3337A (FEN1), rs4989586/ G3259A (FEN1), rs4989587/C3315T (FEN1), and rs1050525/G6941T (PCNA) with breast cancer susceptibility. Statistically significant association with breast cancer risk was observed for rs1130409 homozygous mutant GG [odds ratio (OR) 3.35, 95% confidence interval (CI) 1.36-8.26), heterozygous GT (OR 2.42, 95% CI 1.56-3.76), and combined mutant (GT + GG) (OR 2.52, 95% CI 1.65-3.86] genotypes and rs25487 homozygous mutant AA (OR 2.91, 95% CI 1.66-5.10) and combined mutant (AA + AG) (OR 1.41, 95% CI 0.903-2.19) genotypes, whereas protective association was exhibited by rs1799782 homozygous mutant CC (OR 0.413, 95% CI 0.082-2.08), heterozygous TC (OR 0.351, 95% CI 0.189-0.650), and combined mutant (TC + CC) (OR 0.357, 95% CI 0.199-0.641) genotypes. Association study using reconstructed haplotypes of XRCC1 gene showed positive association for the TA haplotype (OR 2.014, 95% CI 1.462-2.775) and a protective association for the CG haplotype (OR 0.173, 95% CI 0.052-0.576) pertaining to breast cancer risk. The results indicate that the polymorphisms rs1130409 (APEX1) and rs25487 (XRCC1) might be involved in contributing towards breast cancer susceptibility, while rs1799782 (XRCC1) might have protective influence.
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Singh N, Mitra AK, Garg VK, Agarwal A, Sharma M, Chaturvedi R, Rath SK. Association of CYP1A1 Polymorphisms With Breast Cancer in North Indian Women. Oncol Res 2007; 16:587-97. [DOI: 10.3727/000000007783629972] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Gupta D, Chatterjee JM, Ghosh R, Mitra AK, Roy S, Sarkar M. EDXRF analysis of municipal solid waste using 109Cd source. Appl Radiat Isot 2007; 65:512-6. [PMID: 17261366 DOI: 10.1016/j.apradiso.2006.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 09/26/2006] [Accepted: 11/25/2006] [Indexed: 11/18/2022]
Abstract
Elemental compositions of municipal solid waste (MSW) samples have been analyzed using the non-destructive energy dispersive X-ray fluorescence (EDXRF) technique. The samples were collected from three different dumping sites of urban and suburban areas of the city of Kolkata, West Bengal, India. The EDXRF spectrometer consisted of a (109)Cd radioactive source and a Si (Li) detector. To check the reliability of the system, NIST Standard Reference Material-1648 UPM had been analyzed and it was found that within the experimental errors, our results agree quite well with the certified and non-certified values. The elemental compositions of all the three MSW samples were subsequently estimated using the same procedure. The matrix effects were estimated following the emission-transmission method. It was observed that except Fe, all the elements from Ti to Pb show concentration levels higher by a factor of 2-7 than the ecological screening values where as in the case of Fe, this factor varies from 100 to 200.
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Abstract
The long term outcome of stent implantation is affected by a process called in stent restenosis (ISR). Multiple contributory factors have been identified, but clear understanding of the overall underlying mechanism remains an enigma. ISR progresses through several different phases and involves numerous cellular and molecular constituents. Platelets and macrophages play a central role via vascular smooth muscle cell migration and proliferation in the intima to produce neointimal hyperplasia, which is pathognomic of ISR. Increased extracellular matrix formation appears to form the bulk of the neointimal hyperplasia tissue. Emerging evidence of the role of inflammatory cytokines and suppressors of cytokine signalling make this an exciting and novel field of antirestenosis research. Activation of Akt pathway triggered by mechanical stretch may also be a contributory factor to ISR formation. Prevention of ISR appears to be a multipronged attack as no therapeutic "magic bullet" exists to block all the processes in one go.
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Krueger KD, Mitra AK, DelCore MG, Hunter WJ, Agrawal DK. A comparison of stent-induced stenosis in coronary and peripheral arteries. J Clin Pathol 2006; 59:575-9. [PMID: 16473929 PMCID: PMC1860405 DOI: 10.1136/jcp.2004.025643] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND AND OBJECTIVES Restenosis is a complication of interventional procedures such as angioplasty and stenting, often limiting the success of these procedures. Knowledge regarding the relative behaviour of different arteries after these procedures is limited, despite the extensive use of different vascular models. Although the results from studies using different vessels are analysed to predict the behaviour of coronary arteries and other vasculature, direct controlled comparisons between different arteries are necessary for a better understanding of the differential response to restenosis. METHODS This study examines the response to stenting in coronary and internal iliac arteries as characterised by intimal hyperplasia and restenosis. In a swine model of in-stent stenosis, coronary arteries exhibited higher levels of intimal hyperplasia and per cent stenosis than internal iliac arteries. RESULTS After normalisation for injury score, coronary arteries were found to undergo 47% more intimal hyperplasia (p<0.05), whereas per cent stenosis normalised for injury score tended to be higher (p = 0.01). Other measurements reflecting post-stenting intimal hyperplasia (maximal intimal thickness, medial area) did not exhibit significant differences between the artery groups. CONCLUSIONS These results show that coronary vessels are more prone to develop significant intimal hyperplasia and subsequent restenosis than internal iliac vessels. A better insight into how different arteries and arterial components behave is important in understanding and developing newer and better therapeutic measures for restenosis.
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Tow BPB, Chang PCC, Mitra AK, Tay BK, Wong MC. Comparing 2-year outcomes of anterior cruciate ligament reconstruction using either patella-tendon or semitendinosus-tendon autografts: a non-randomised prospective study. J Orthop Surg (Hong Kong) 2005; 13:139-46. [PMID: 16131675 DOI: 10.1177/230949900501300206] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE To compare the results of anterior cruciate ligament (ACL) reconstructions using either a patella-tendon autograft or a semitendinosus-tendon autograft. METHODS Based on surgeon experience and preference, 68 patients underwent ACL reconstruction using either a quadruple-strand semitendinosus autograft (n = 34) or a central one-third bone-patella tendon-bone autograft (n = 34). Each patient was assessed preoperatively and postoperatively at 3, 6, and 24 months using the International Knee Documentation Committee (IKDC) knee score, Biodex muscle strength and endurance testing, and the KT1000 instrumented arthrometer test of knee laxity to anterior translation. All assessments at the 2-year follow-up were performed by the same physician and physiotherapist. RESULTS While ACL reconstruction improved knee stability and IKDC knee scores significantly, there was no statistically significant difference between semitendinosus- and patella-tendon autograft reconstructions in terms of long-term knee score or laxity to anterior translation. Semitendinosus graft reconstruction was associated with less donor-site morbidity and hamstring weakness. Meniscectomy was associated with poorer long-term knee scores. CONCLUSION ACL reconstruction is associated with a significantly better IKDC knee score and laxity measurement at 2-year follow-up. However, we were unable to demonstrate a significantly better long-term outcome in knee score or laxity to anterior translation with either a patella-tendon autograft or a semitendinosus-tendon autograft.
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Tan AHC, Mitra AK, Chang PCC, Tay BK, Nag HL, Sim CS. Assessment of blood-induced cartilage damage in rabbit knees using scanning electron microscopy. J Orthop Surg (Hong Kong) 2004; 12:199-204. [PMID: 15621907 DOI: 10.1177/230949900401200212] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To investigate the harmful effects of a single episode of intra-articular bleeding on articular cartilage of rabbit knees using scanning electron microscopy. METHODS Autologous blood was injected into the right knee joints of 18 New Zealand white rabbits. Surface and cellular damages were examined by the scanning electron microscope (n=9) and light microscope (n=34), respectively. The injected right knees were then compared with the corresponding control left knees at one, 3, and 6 weeks after the blood injection. RESULTS The articular surface of the injected knees turned uniformly rough with multiple pits after one week. Maximal changes with elevations and depressions were observed at 3 weeks. These changes reversed at 6 weeks with the irregularities smoothing out. A similar pattern of transient cartilage damage was noted histologically. CONCLUSION Both scanning electron microscopic and light microscopic findings suggest that a single episode of intra-articular bleeding leads to articular cartilage damage but this appears to be reversible. Our findings of transient damage to the articular cartilage suggest that there is no need for intra-articular evacuation and washout following an acute episode of haemarthrosis.
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Das HK, Mitra AK, Sengupta PK, Hossain A, Islam F, Rabbani GH. Arsenic concentrations in rice, vegetables, and fish in Bangladesh: a preliminary study. ENVIRONMENT INTERNATIONAL 2004; 30:383-7. [PMID: 14987870 DOI: 10.1016/j.envint.2003.09.005] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2002] [Accepted: 09/09/2003] [Indexed: 05/21/2023]
Abstract
Arsenic contaminating groundwater in Bangladesh is one of the largest environmental health hazards in the world. Because of the potential risk to human health through consumption of agricultural produce grown in fields irrigated with arsenic contaminated water, we have determined the level of contamination in 100 samples of crop, vegetables and fresh water fish collected from three different regions in Bangladesh. Arsenic concentrations were determined by hydride generation atomic absorption spectrophotometry. All 11 samples of water and 18 samples of soil exceeded the expected limits of arsenic. No samples of rice grain (Oryza sativa L.) had arsenic concentrations more than the recommended limit of 1.0 mg/kg. However, rice plants, especially the roots had a significantly higher concentration of arsenic (2.4 mg/kg) compared to stem (0.73 mg/kg) and rice grains (0.14 mg/kg). Arsenic contents of vegetables varied; those exceeding the food safety limits included Kachu sak (Colocasia antiquorum) (0.09-3.99 mg/kg, n=9), potatoes (Solanum tuberisum) (0.07-1.36 mg/kg, n=5), and Kalmi sak (Ipomoea reptoms) (0.1-1.53 mg/kg, n=6). Lata fish (Ophicephalus punctatus) did not contain unacceptable levels of arsenic. These results indicate that arsenic contaminates some food items in Bangladesh. Further studies with larger samples are needed to demonstrate the extent of arsenic contamination of food in Bangladesh.
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Soon M, Neo CPC, Mitra AK, Tay BK. Morbidity following anterior cruciate ligament reconstruction using hamstring autograft. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2004; 33:214-9. [PMID: 15098637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
INTRODUCTION As anterior cruciate ligament (ACL) reconstruction becomes more frequently performed, the expectation of earlier return to activities becomes higher; hence graft selection becomes more important. The use of hamstring tendon autograft is perceived to have less postoperative morbidities. We evaluate the early postoperative complications in this prospective study. MATERIALS AND METHODS Seventy-six patients operated by the same surgeon were assessed preoperatively, and 3 and 6 months after surgery. The hamstring and quadriceps strength were measured with Biodex machine and the side-to-side laxity measured using KT-1000 instrument. The patients were also assessed for their subjective complaints using IKDC (International Knee Documentation Committee) Knee Scoring System. RESULTS The strength and endurance index of the quadriceps and hamstrings recovered and improved by the sixth month after surgery. The recovery by the quadriceps muscle is more marked and by the sixth month, it has recovered to more than the preoperative level. As for laxity, the average side-to-side difference at 30 pounds was 2.75 mm by 6 months. Of these patients, the side-to-side difference was less than 5 mm in 66 patients (5 mm as taken to be acceptable for graft success). As for IKDC rating, at the sixth month, 71 patients had normal or near normal knee by their own assessment. No patients had anterior knee pain at rest. Sensory deficits were only present in 3 patients with complaints of numbness over the distribution of the saphenous nerve or its infrapatellar branch. CONCLUSION Most morbidities are temporal in nature and do not significantly affect the patient's activities.
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Chia SL, Kapoor V, Ali MM, Lie D, Chang PCC, Mitra AK, Tay BK. The posterior cruciate ligament: an anthropometric study in Asians and evaluation of safe limits for bony tunnel creation during reconstruction. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2002; 31:631-5. [PMID: 12395651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
INTRODUCTION Quantitative data regarding the dimensions of the posterior cruciate ligament (PCL) and its insertions have not been studied in Asians, and concerns have been raised regarding the danger of vascular injury when the bony tunnels are created during arthroscopically-assisted reconstruction. MATERIALS AND METHODS Ten male cadavers were used in this study, incorporating dissection and procedural arms. In the procedural arm, the path of the drill bit was tracked fluoroscopically as the tibial and femoral tunnels were created during simulated reconstructive surgery, and the effect of varying knee flexion angles was studied. Fluoroscopic images were analysed using specialised image processing software. RESULTS The mean length of the PCL at full extension was 37.7 +/- 1.9 mm, and the mean mid-substance width was 13.7 +/- 1.7 mm. The mean sagittal distance between the exit point of the tibial tunnel and the anterior surface of the popliteal artery, across all knee flexion positions, was merely 6.0 mm (range, 2.8 to 10.2 mm). This distance tended to increase with increasing knee flexion, but this was not statistically significant. The mean distance between the exit point of the femoral tunnel and the femoral artery was 51.1 mm (range, 42.1 to 59.0 mm). CONCLUSIONS The dimensions of the PCL and its insertions in Asians do not vary greatly from those reported for Western subjects. The distance from the exit point of the tibial tunnel to the popliteal artery is very small and, although this distance increases with increasing knee flexion, the improvement in the safety margin may neither be clinically nor statistically significant. The margin of safety for drilling of the femoral tunnel is much greater.
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Hebbar SA, Mitra AK, George KC, Verma NC. Caffeine ameliorates radiation-induced skin reactions in mice but does not influence tumour radiation response. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2002; 22:63-69. [PMID: 11929115 DOI: 10.1088/0952-4746/22/1/306] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Intramuscular administration of caffeine at a dose of 80 mg kg(-1) body weight to the gastrocnemius muscles of Swiss mice 5 min prior to local irradiation (35 Gy) of the leg delayed the progression of radiation-induced skin reactions in such animals. While 90% epilation with reddening of the skin was noted in animals treated with radiation alone, animals pretreated with caffeine suffered only partial hair loss with slight reddening of the skin on the 16th and 20th days post-irradiation. Beyond the 28th day, damage scores in irradiated feet for both the groups were similar (score 3) and remained unchanged until the 32nd day and then decreased and disappeared completely in both treatment groups by the 40th day after irradiation. In addition, the effect of caffeine on the radiation response of a mouse fibrosarcoma was investigated. Results showed that intratumoral administration of caffeine at a dose of 80 mg kg(-1) body weight 5 min prior to local exposure of tumours to 10 Gy of 60Co gamma-rays did not influence the response of tumours to radiation. The present study thus showed that although caffeine ameliorated radiation-induced skin reactions in the mouse leg, it did not affect the tumour radiation response, indicating its potential application in cancer radiotherapy.
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Pezron I, Tirucherai GS, Mitra AK. Time-dependent loss of radioactivity counts associated with paracellular markers in the presence of cyclodextrin. Int J Pharm 2002; 231:237-40. [PMID: 11755275 DOI: 10.1016/s0378-5173(01)00883-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This communication reports an unexpected phenomenon observed during the counting of radiolabeled paracellular marker solutions in the presence of 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD). The results revealed time-dependent loss of 14C-mannitol and 14C-polyethlene glycol 4000 radioactivity counts with increased percentages of HPbetaCD. However, 14C-diazepam, a transcellular marker, displayed a stable count. A hypothesis behind this phenomenon is being proposed, involving water transfer from aqueous droplets to the surfactant rich scintillation fluid. The remaining droplets, becoming more and more concentrated in cyclodextrin, entrap the hydrophilic markers and consequently exhibit an increasing quenching effect. This effect shows that careful monitoring of radiolabeled markers used in transport experiments is necessary, even with high quench resistant scintillation fluids, to prevent erroneous interpretation of the transport data.
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Kuchimanchi KR, Gandhi MD, Sheta RR, Johnston TP, Santhosh KC, Cushman M, Mitra AK. Intestinal absorption and biodistribution of cosalane and its amino acid conjugates: novel anti-HIV agents. Int J Pharm 2002; 231:197-211. [PMID: 11755272 DOI: 10.1016/s0378-5173(01)00884-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Cosalane and its amino acid conjugates are potent inhibitors of HIV replication. The purpose of this study was to investigate: (1) the pharmacokinetic disposition of the diglycine (GC) and the diaspartic acid (ASPC) conjugates of cosalane in male Sprague-Dawley rats; (2) intestinal absorption of cosalane and its amino acid conjugates using in vitro (small intestinal segments), in situ (closed loop); and (3) biodistribution of GC and its absolute oral bioavailability in rat. Cosalane and its conjugates exhibited biexponential disposition with very long half-lives upon intravenous dosing. However, these compounds failed to permeate the small intestine unless sodium desoxycholate (5-20 mM) was used as an intestinal permeation enhancer. A rank order correlation in terms of permeation enhancement in a descending order is as follows: GC>Cosalane>ASPC. In situ studies revealed that although the bile salt enhanced the permeation of cosalane across the enterocyte, its hepatic uptake was extensive. However, 66% of the absorbed dose of GC escaped uptake by the reticuloendothelial system (RES) and its biodistribution studies showed that the uptake by the RES was significantly lower compared to the parent compound. GC had an absolute oral bioavailability of 5.10+/-1.51%. Therefore, GC appears to be a favorable candidate for further development.
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Ashraf H, Mahalanabis D, Mitra AK, Tzipori S, Fuchs GJ. Hyperimmune bovine colostrum in the treatment of shigellosis in children: a double-blind, randomized, controlled trial. Acta Paediatr 2001; 90:1373-8. [PMID: 11853331 DOI: 10.1080/08035250152708743] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
UNLABELLED Immunological approaches have been considered as an alternative therapeutic option for the treatment of enteric infections over the past few years. Hyperimmune bovine colostrum (HBC) is a potentially innovative immunological option in the management of shigellosis together with traditional antibiotic therapy. Children aged 1-12 y with a history of bloody mucoid diarrhoea of less than 5 d duration were enrolled after their stool specimen was found to be positive for Shigella dysenteriae type I antigen by a rapid diagnostic fluorescent antibody staining test. They were randomized to receive either HBC containing very high titres of antibody against S. dysenteriae type I antigen or bovine colostrum (BC) without any antibody. The study group received 100 ml of HBC three times a day orally for 3 d and control group received BC. Children also received pivmecillinam in a dose of 50 mg kg(-1) d(-1) in four divided doses orally for 5 d. Admission characteristics of the 34 children in the HBC group and 35 in the BC group were comparable. No significant differences were observed in duration of diarrhoea, fever, anorexia, abdominal pain, tenesmus, stool frequency or visible blood in the stool between the groups. Two (6%) children in the study and five (14%) in the control group remained stool culture positive for S. dysenteriae type 1, even after 5 d of sensitive antimicrobial therapy. CONCLUSION The results indicate that HBC as an adjuvant is unable to show any beneficial effect in reducing the stool frequency, duration or severity of childhood shigellosis due to S. dysenteriae type I infection.
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Patel J, Mitra AK. Strategies to overcome simultaneous P-glycoprotein mediated efflux and CYP3A4 mediated metabolism of drugs. Pharmacogenomics 2001; 2:401-15. [PMID: 11722289 DOI: 10.1517/14622416.2.4.401] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cytochrome P450 3A4 (CYP3A4), abundant in both the liver and upper intestinal enterocytes, limits the systemic bioavailability of xenobiotics. P-glycoprotein (P-gp), the MDR1 gene product, is also known to reduce the oral bioavailability of the drug molecules. High cellular expression of P-gp and CYP3A4 in mature intestinal enterocytes and their similar substrate specificity suggest that the function of these proteins may be complementary and may form a co-ordinated intestinal barrier. Various ongoing preclinical and clinical studies have demonstrated that the oral bioavailability of various P-gp and/or CYP3A4 substrates can be increased by simultaneous administration of P-gp and/or CYP3A4 inactivators. The current review describes the background and summarises several proposed hypotheses in modifying oral bioavailability by various drug-inhibitor interactions.
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