Subhrojit Sen

Publications

• 1.75

  Impact points

  Preventive effects of North American Ginseng (Panax quinquefolius) on Diabetic Retinopathy and Cardiomyopathy.

  Subhrojit Sen, Shali Chen, Yuexiu Wu, Biao Feng, Edmund K Lui, Subrata Chakrabarti

  Phytotherapy research : PTR. 05/2012;

  Ginseng (Araliaceae) has multiple pharmacological actions because of its diverse phytochemical constituents. The aims of the present study are to evaluate the preventive effects of North American ginseng on diabetic retinopathy and cardiomyopathy and to delineate the underlying mechanisms of such ef... [more] Ginseng (Araliaceae) has multiple pharmacological actions because of its diverse phytochemical constituents. The aims of the present study are to evaluate the preventive effects of North American ginseng on diabetic retinopathy and cardiomyopathy and to delineate the underlying mechanisms of such effects. Models of both type 1 (C57BL/6 mice with streptozotocin-induced diabetes) and type 2 diabetes (db/db mice) and age-matched and sex-matched controls were examined. Alcoholic ginseng root (200 mg/kg body weight, daily oral gavage) extract was administered to groups of both type 1 and type 2 diabetic mice for 2 or 4 months. Dysmetabolic state in the diabetic mice was significantly improved by ginseng treatment. In both the heart and retina of diabetic animals, ginseng treatment significantly prevented oxidative stress and diabetes-induced upregulations of extracellular matrix proteins and vasoactive factors. Ginseng treatment in the diabetic animals resulted in enhancement of stroke volume, ejection fraction, cardiac output, and left ventricle pressure during systole and diastole and diminution of stroke work. In addition, mRNA expressions of atrial natriuretic factor and brain natriuretic factor (molecular markers for cardiac hypertrophy) were significantly diminished in ginseng-treated diabetic mice. These data indicate that North American ginseng prevents the diabetes-induced retinal and cardiac biochemical and functional changes probably through inhibition of oxidative stress. Copyright © 2012 John Wiley & Sons, Ltd.
• 2.17

  Impact points

  Preventive effects of North American ginseng (Panax quinquefolium) on diabetic nephropathy

  Subhrojit Sen, Shali Chen, Biao Feng, Yuexiu Wu, Edmund Lui, Subrata Chakrabarti

  Phytomedicine. 02/2012;
• 8.51

  Impact points

  miR-146a-Mediated extracellular matrix protein production in chronic diabetes complications.

  Biao Feng, Shali Chen, Kara McArthur, Yuexiu Wu, Subhrojit Sen, Qingming Ding, Ross D Feldman, Subrata Chakrabarti

  Diabetes. 09/2011; 60(11):2975-84.

  MicroRNAs (miRNAs), through transcriptional regulation, modulate several cellular processes. In diabetes, increased extracellular matrix protein fibronectin (FN) production is known to occur through histone acetylator p300. Here, we investigated the role of miR-146a, an FN-targeting miRNA, on FN pro... [more] MicroRNAs (miRNAs), through transcriptional regulation, modulate several cellular processes. In diabetes, increased extracellular matrix protein fibronectin (FN) production is known to occur through histone acetylator p300. Here, we investigated the role of miR-146a, an FN-targeting miRNA, on FN production in diabetes and its relationship with p300. miR-146a expressions were measured in endothelial cells from large vessels and retinal microvessels in various glucose levels. FN messenger RNA expression and protein levels with or without miR-146a mimic or antagomir transfection were examined. A luciferase assay was performed to detect miR-146a's binding to FN 3'-untranslated region (UTR). Likewise, retinas from type 1 diabetic rats were studied with or without an intravitreal injection of miR-146a mimic. In situ hybridization was used to localize retinal miR-146a. Cardiac and renal tissues were analyzed from type 1 and type 2 diabetic animals. A total of 25 mmol/L glucose decreased miR-146a expression and increased FN expression compared with 5 mmol/L glucose in both cell types. miR-146a mimic transfection prevented such change, whereas miR-146a antagomir transfection in the cells in 5 mmol/L glucose caused FN upregulation. A luciferase assay confirmed miR-146a's binding to FN 3'-UTR. miR-146a was localized in the retinal endothelial cells and was decreased in diabetes. Intravitreal miR-146a mimic injection restored retinal miR-146a and decreased FN in diabetes. Additional experiments showed that p300 regulates miR-146a. Similar changes were seen in the retinas, kidneys, and hearts in type 1 and type 2 diabetic animals. These studies showed a novel, glucose-induced molecular mechanism in which miR-146a participates in the transcriptional circuitry regulating extracellular matrix protein production in diabetes.
• 2.17

  Impact points

  American ginseng (Panax quinquefolius) prevents glucose-induced oxidative stress and associated endothelial abnormalities.

  Subhrojit Sen, Shali Chen, Biao Feng, Yuexiu Wu, Edmund Lui, Subrata Chakrabarti

  Phytomedicine : international journal of phytotherapy and phytopharmacology. 08/2011; 18(13):1110-7.

  Ginseng (Araliaceae), demonstrates widespread biological effects because of its purported antioxidant and other properties. The present study was undertaken to investigate the effects of American ginseng root extract on glucose-induced oxidative stress and associated oxidative damage to human umbili... [more] Ginseng (Araliaceae), demonstrates widespread biological effects because of its purported antioxidant and other properties. The present study was undertaken to investigate the effects of American ginseng root extract on glucose-induced oxidative stress and associated oxidative damage to human umbilical vein endothelial cells (HUVECs). Following pretreatment with various concentrations of ginseng (alcoholic extract), HUVECs were incubated with various concentrations of d-glucose ranging from 5 to 25mmol/l for 24h. l-Glucose was used at a concentration of 25mmol/l as a control. Glucose-induced oxidative stress detected by intracellular reactive oxygen species accumulation, superoxide anion generation and DNA damage in HUVECs were significantly prevented by ginseng. Treatment of HUVECs with ginseng further led to significant prevention of glucose-induced NF-κB activation. Glucose-induced increase in fibronectin (FN), EDB(+)FN (a splice variant of FN), endothelin-1 (ET-1) and vascular endothelial growth factor (VEGF) mRNAs and protein levels were also prevented by ginseng treatment. These data indicate that American ginseng prevented glucose-induced damage in the HUVECs through its antioxidant properties.

• Ameliorative effects of glycyrrhizin on streptozotocin-induced diabetes in rats.

  Subhrojit Sen, Moumita Roy, Abhay Sankar Chakraborti

  The Journal of pharmacy and pharmacology. 02/2011; 63(2):287-96.

  Glycyrrhizin is the main water-soluble constituent of the root of liquorice (Glycyrrhiza glabra). The study investigates the effect of glycyrrhizin on streptozotocin (STZ)-induced diabetic changes and associated oxidative stress, including haemoglobin-induced free iron-mediated oxidative reactions. ... [more] Glycyrrhizin is the main water-soluble constituent of the root of liquorice (Glycyrrhiza glabra). The study investigates the effect of glycyrrhizin on streptozotocin (STZ)-induced diabetic changes and associated oxidative stress, including haemoglobin-induced free iron-mediated oxidative reactions. Male Wistar rats were grouped as normal control, STZ-induced diabetic control, normal treated with glycyrrhizin, diabetic treated with glycyrrhizin and diabetic treated with a standard anti-hyperglycaemic drug, glibenclamide. Different parameters were studied in blood and tissue samples of the rats. Glycyrrhizin treatment improved significantly the diabetogenic effects of STZ, namely enhanced blood glucose level, glucose intolerant behaviour, decreased serum insulin level including pancreatic islet cell numbers, increased glycohaemoglobin level and enhanced levels of cholesterol and triglyceride. The treatment significantly reduced diabetes-induced abnormalities of pancreas and kidney tissues. Oxidative stress parameters, namely, serum superoxide dismutase, catalase, malondialdehyde and fructosamine in diabetic rats were reverted to respective normal values after glycyrrhizin administration. Free iron in haemoglobin, iron-mediated free radical reactions and carbonyl formation in haemoglobin were pronounced in diabetes, and were counteracted by glycyrrhizin. Effects of glycyrrhizin and glibenclamide treatments appeared comparable. Glycyrrhizin is quite effective against hyperglycaemia, hyperlipidaemia and associated oxidative stress, and may be a potential therapeutic agent for diabetes treatment.

• Preventive effects of Panax quinquefolius (American ginseng) on diabetic nephropathy

  Subrata Chakrabarti Subhrojit Sen, Shali Chen, Biao Feng, Yuexiu Wu, Kara McArthur, Edmund Lui1

  Recent development in chinese herbal medicine, Singapore; 01/2010

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• PANAX QUINQUEFOLIUS (AMERICAN GINSENG) PREVENTS CHRONIC COMPLICATIONS IN TYPE 1 AND TYPE 2 DIABETES THROUGH ITS ANTIOXIDATIVE AND ANTIHYPERGLYCEMIC EFFECTS

  Subrata Chakrabarti Subhrojit Sen, Shali Chen, Biao Feng, Edmund Lui

  The 10th International Symposium on Ginseng, Korea; 01/2010

  Introduction: Chronic diabetic complications are major causes of mortality and morbidity worldwide. Glucose induced oxidative stress is a key pathogenetic factor in chronic diabetic complications. Among the chronic complications, diabetic nephropathy is a major cause of renal failure. Similarly diab... [more] Introduction: Chronic diabetic complications are major causes of mortality and morbidity worldwide. Glucose induced oxidative stress is a key pathogenetic factor in chronic diabetic complications. Among the chronic complications, diabetic nephropathy is a major cause of renal failure. Similarly diabetic cardiomyopathy may lead to cardiac failure in the diabetics. Ginseng (Araliaceae), demonstrates widespread biological effects and several of such effects are mediated by prevention of oxidative stress. The aim of the present study was undertaken to examine possible preventive effects of American ginseng on diabetic nephropathy and cardiomyopathy and possible mechanisms of such prevention. Methods: Both models of type 1 (C57BL mice with STZ-induced diabetes) and type 2 diabetes (db/db mice) and age- and sex- matched controls were examined. A group of diabetic mice were treated with ethanolic extract of ginseng (containing 8.53% total ginsenosides,200 mg/Kg body wt, oral gavage daily) for 2 or 4 months. The animals were monitored with respect to body weight, blood glucose, glycated Hb., serum and urinary creatinine, urinary albumin levels. Hemodynamic assessments of cardiac functions were performed. Tissues were analysed for mRNA and proteins of interest and were examined for oxidative stress and structural damage To identify the mechanism of ginseng’s action we tested cultured endothelial cells (ECs) exposed to various glucose levels and ginseng extracts. mRNA and proteins from these cells were investigated for vasoactive factors, extracellular matrix proteins and markers of oxidative stress Results: In both models, diabetes caused hyperglycemia, albuminuria, creatinuria, elevated glycated hemoglobin levels and body weight abnormalities. Diabetic mice treated with ginseng showed significant improvement of these abnormalities. Futhermore, in both models, cardiac failure induced by diabetes were prevented by ginseng treatment. In the kidneys of diabetic animals, ginseng significantly reduced diabetes-induced fibronectin(FN) , EDB fibronectin (EDBFN) , Endothelin-1(ET1), vascular endothelial growth factor(VEGF) and transforming growth factor-β1(TGFB1) mRNA upregulations and oxidative stress. Furthermore, diabetes induced structural damage to the tissues were prevented. Similarly in the ECs, glucose induced upregulation of FN, EDBFN, ET1 and VEGF were prevented by ginseng treatment. Alcoholic extract of ginseng was more efficient than the aqueous extract in such prevention. Furthermore, 8-OHDG and H2AX, two established markers of glucose-induced oxidative DNA damage were prevented by ginseng. Conclusion: Data from these studies indicate that ginseng treatment can prevent diabetic nephropathy and cardiomyopathy. Such effects are possibly mediated through both its antioxidant and antihyperglycemic properties.

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• American Ginseng (Panax quinquefolius) prevents diabetes induced retinal changes

  Subhrojit Sen, Yuexiu Wu, Shali Chen, Biao Feng, Kara McArthur, Subrata Chakraborti

  9th Meeting of Consortium for Globalization of Chinese Medicine (CGCM), Hong Kong; 01/2010

  Diabetic retinopathy(DR) is the most serious ophthalmic complication of diabetes leading to most of the cases of legal blindness in the western world. Furthermore, DR is also the commonest cause of visual impairment in the age group 30 - 65 years. Oxidative stress contributes to the pathogenesis of... [more] Diabetic retinopathy(DR) is the most serious ophthalmic complication of diabetes leading to most of the cases of legal blindness in the western world. Furthermore, DR is also the commonest cause of visual impairment in the age group 30 - 65 years. Oxidative stress contributes to the pathogenesis of several chronic diabetic complications including DR. Ginseng(Araliaceae), an herb demonstrates widespread biological effects, primarily due to its antioxidant properties. The present study was undertaken to investigate the effects of ginseng on DR. As endothelial cells are primary targets in DR, we investigated preventive effects of ginseng on glucose-induced changes in human umbilical vein endothelial cells(HUVECs). We also examined the preventive effects of ginseng on retinal damage in both type 1(STZ-induced) and type 2 models(db/db) of diabetes. HUVECs were incubated with 25 mM glucose for 24 hrs with or without ginseng(ethanolic extract). Diabetic mice were treated for 2 months with ethanolic extract of ginseng (200 mg/Kg, oral gavage) and were compared with age- and sex-matched controls. In HUVECs, treatment with ginseng caused significant diminution of glucose-induced fibronectin(FN), EDB+ FN(its splice variant), endothlin-1(ET-1), vascular endothelial growth factor(VEGF) heme oxygenase-1 (HO-1) mRNA levels. Ginseng further prevented glucose-induced decrease in FN, VEGF and ET-1 protein levels. Glucose-induced oxidative stress detected by intracellular reactive oxygen species accumulation and DNA damage in HUVECs were further prevented by ginseng. Both in STZ-mice and db/db mice, treatment with ginseng significantly reduced blood glucose and glycated hemoglobin levels. Furthermore, ginseng treatment resulted in the reduction of body weight in the db/db mice. In both animal models, ginseng treatment prevented diabetes induced upregulation of retinal FN and EDB+FN,VEGF and HO-1 mRNA levels. These results suggest that ginseng prevents pathogenetic processes leading to retinal damage in diabetes, through its antioxidative and antihyperglycemic properties. Acknowledgment: Supported by grant from Ministry of Research & Innovation, Ontario Research Fund – Research Excellence
• 2.76

  Impact points

  Leptin and endothelin-1 mediated increased extracellular matrix protein production and cardiomyocyte hypertrophy in diabetic heart disease.

  Pijush Majumdar, Shali Chen, Biju George, Subhrojit Sen, Morris Karmazyn, Subrata Chakrabarti

  Diabetes/metabolism research and reviews. 05/2009;

  BACKGROUND: We investigated the role of leptin and its interaction with endothelin 1 (ET-1) in fibronectin (FN) synthesis and cardiomyocyte hypertrophy, two characteristic features of diabetic cardiomyopathy. METHODS: Endothelial cells [human umbilical vein endothelial cells (HUVECs)] were examined ... [more] BACKGROUND: We investigated the role of leptin and its interaction with endothelin 1 (ET-1) in fibronectin (FN) synthesis and cardiomyocyte hypertrophy, two characteristic features of diabetic cardiomyopathy. METHODS: Endothelial cells [human umbilical vein endothelial cells (HUVECs)] were examined for FN production and neonatal rat cardiomyocytes for hypertrophy, following incubation with glucose, ET-1, leptin and specific blockers. FN, ET-1, leptin and leptin receptors mRNA expression and FN protein were measured. Myocytes were also morphometrically examined. Furthermore, hearts from streptozotocin-diabetic rats were analysed. RESULTS: Glucose caused increased FN mRNA and protein expression in HUVECs and cardiomyocytes hypertrophy along with upregulation of ET-1 mRNA, leptin mRNA and protein. Glucosemimetic effects were seen with leptin and ET-1. Leptin receptor antagonist (leptin quadruple mutant) and dual endothelin A endothelin B (ETA/ETB) receptor blocker bosentan normalized such abnormalities. Hearts from the diabetic animals showed hypertrophy and similar mRNA changes. CONCLUSION: These data indicate that in diabetes increased FN production and cardiomyocyte hypertrophy may be mediated through leptin with its interaction with ET-1. Copyright (c) 2009 John Wiley & Sons, Ltd.

• The preventive effects of ginseng (Panax quinquefolius) on glucose-induced endothelial cell abnormalities and diabetic nephropathy

  Subhrojit Sen, Shali Chen, Biao Feng, Yuexiu Wu, Kara McArthur, Subrata Chakrabarti

  Annual Conference of Ontario Ginseng Innovation & Research Consortium, 6-7th Nov., University of Western Ontario; 01/2009

  Diabetes mellitus consists of a heterogeneous group of clinical conditions with elevation of the blood glucose level as a central feature. Overall 40% of diabetics develop long-term complications affecting various organs including kidney, heart and retina. Oxidative stress contributes to the pathoge... [more] Diabetes mellitus consists of a heterogeneous group of clinical conditions with elevation of the blood glucose level as a central feature. Overall 40% of diabetics develop long-term complications affecting various organs including kidney, heart and retina. Oxidative stress contributes to the pathogenesis of various diabetic complications. Ginseng (Araliaceae), an herb demonstrates widespread biological effects because of its antioxidant and other properties. The present study was undertaken to investigate the effects of ginseng on glucose-induced changes in human vascular endothelial cells (HUVECs). We further extended our investigation to study the preventive effects of ginseng on diabetes-induced renal damage. HUVECs were incubated with 25 mM glucose for 24 hrs with or without Ginseng (ethanolic extract). For in vivo experiments we used C57BL mice with STZ-induced diabetes and db/db mice (Leprdb, DBA/J). Diabetic mice were treated with ethanolic extract of ginseng (200 mg/Kg body wt, oral gavage, 2 months). Treatment of HUVECs with ginseng caused significant diminution of glucose-induced fibronectin (FN), EDB+ FN (its splice variant), endothlin-1 (ET-1) and vascular endothelial growth factor (VEGF) mRNA levels. Ginseng further prevented glucose-induced increase in FN protein levels. For IDDM set, diabetic mice treated with ginseng showed significant reduction of blood glucose, glycated hemoglobin, urinary albumin and creatinine levels. Similar results were found with db/db mice treated with ginseng. In the kidneys of diabetic animals (IDDM), ginseng significantly reduced diabetes-induced FN, ET-1, EDB+FN, VEGF and TGF-β mRNA upregulations. For NIDDM set, ginseng significantly reduced FN, VEGF and collagen mRNA levels in kidney tissues. These results suggest that ginseng prevents pathogenetic processes leading to chronic diabetic complications, through its antioxidative and antihyperglycemic properties.

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• 2.56

  Impact points

  Action of pelargonidin on hyperglycemia and oxidative damage in diabetic rats: implication for glycation-induced hemoglobin modification.

  Moumita Roy, Subhrojit Sen, Abhay Sankar Chakraborti

  Life sciences. 06/2008; 82(21-22):1102-10.

  Glycation-modified hemoglobin in diabetes mellitus has been suggested to be a source of enhanced catalytic iron and free radicals causing pathological complications. The present study aims to verify this idea in experimental diabetes. Pelargonidin, an anthocyanidin, has been tested for its antidiabe... [more] Glycation-modified hemoglobin in diabetes mellitus has been suggested to be a source of enhanced catalytic iron and free radicals causing pathological complications. The present study aims to verify this idea in experimental diabetes. Pelargonidin, an anthocyanidin, has been tested for its antidiabetic potential with emphasis on its role against pathological oxidative stress including hemoglobin-mediated free radical reactions. Male wistar rats were grouped as normal control, streptozotocin-induced diabetic control, normal treated with pelargonidin and diabetic treated with pelargonidin. Pelargonidin-treated rats received one time i.p injection of the flavonoid (3 mg/kg bodyweight). Biochemical parameters were assayed in blood samples of different groups of rats. Liver was used for histological examinations. Pelargonidin treatment normalized elevated blood glucose levels and improved serum insulin levels in diabetic rats. Glucose tolerance test appeared normal after treatment. Decreased serum levels of SOD and catalase, and increased levels of malondialdehyde and fructosamine in diabetic rats were reverted to their respective normal values after pelargonidin administration. Extents of hemoglobin glycation, hemoglobin-mediated iron release, iron-mediated free radical reactions and carbonyl formation in hemoglobin were pronounced in diabetic rats, indicating association between hemoglobin glycation and oxidative stress in diabetes. Pelargonidin counteracts hemoglobin glycation, iron release from the heme protein and iron-mediated oxidative damages, confirming glycated hemoglobin-associated oxidative stress in diabetes.

• STUDIES ON DIFFERENT BIOCHEMICAL ASPECTS OF DIABETES MELLITUS

  SUBHROJIT SEN

  05/2008

  Degree: Ph.D

  Supervisor: ABHAY SANKAR CHAKRABORTI
• 1.90

  Impact points

  Effect of non-enzymatic glycation on esterase activities of hemoglobin and myoglobin.

  Subhrojit Sen, Tania Bose, Anjana Roy, Abhay Sankar Chakraborti

  Molecular and cellular biochemistry. 08/2007; 301(1-2):251-7.

  Heme proteins--hemoglobin and myoglobin possess esterase activities. Studies with purified hemoglobin from normal individuals and diabetic patients revealed that the esterase activity as measured from hydrolysis of p-nitrophenyl acetate (p-NPA) was higher in diabetic condition and increased progress... [more] Heme proteins--hemoglobin and myoglobin possess esterase activities. Studies with purified hemoglobin from normal individuals and diabetic patients revealed that the esterase activity as measured from hydrolysis of p-nitrophenyl acetate (p-NPA) was higher in diabetic condition and increased progressively with extent of the disease. HbA(1c), the major glycated hemoglobin, which increases proportionately with blood glucose level in diabetes mellitus, exhibited more esterase activity than the non-glycated hemoglobin fraction, HbA(0), as demonstrated spectrophotometrically as well as by activity staining. Glycation influenced esterase activity of hemoglobin by increasing the affinity for the substrate and the rate of the reaction. Both HbA(0) and HbA(1c)-mediated catalysis of p-NPA hydrolysis was pH-dependent. Esterase activity of in vitro-glycated myoglobin (GMb) was also higher than that of its non-glycated analog (Mb). The amplified esterase activities of hemoglobin and myoglobin might be associated with glycation-induced structural modifications of the proteins.

• Inhibitory effect of glycyrrhizin on diabetic complications and associated oxidative stress

  S. Sen, M. Roy, A. S. Chakraborti

  Chromosomes to Neurons, Saha Institute of Nuclear Physics, Kolkata, India; 01/2007

• Glycation-induced heme degradation and iron release from heme proteins: A mechanism of increased formation of free radicals and oxidative stress in diabetes mellitus

  T. Bose, S. Sen, M. Roy, A. Roy, A. S. Chakraborti

  Gordon Research Conference on Tetrapyrroles, Salve Regina University, New Port, Rhode Island, USA; 07/2006
• 2.28

  Impact points

  Effect of nonenzymatic glycation on functional and structural properties of hemoglobin.

  Subhrojit Sen, Manoj Kar, Anjana Roy, Abhay Sankar Chakraborti

  Biophysical chemistry. 04/2005; 113(3):289-98.

  HbA(1c), the major glycated hemoglobin increases proportionately with blood glucose concentration in diabetes mellitus. H(2)O(2) promotes more iron release from HbA(1c) than that from nonglycated hemoglobin, HbA(0). This free iron, acting as a Fenton reagent, might produce free radicals and degrade ... [more] HbA(1c), the major glycated hemoglobin increases proportionately with blood glucose concentration in diabetes mellitus. H(2)O(2) promotes more iron release from HbA(1c) than that from nonglycated hemoglobin, HbA(0). This free iron, acting as a Fenton reagent, might produce free radicals and degrade cell constituents. Here we demonstrate that in the presence of H(2)O(2), HbA(1c) degrades DNA and protein more efficiently than HbA(0). Formation of carbonyl content, an index of oxidative stress, is higher by HbA(1c). Compared to HbA(0), HbA(1c) is more rapidly autooxidized. Besides these functional changes, glycation also causes structural modifications of hemoglobin. This is demonstrated by reduced alpha-helix content, more surface accessible hydrophobic tryptophan residues, increased thermolability and weaker heme-globin linkage in HbA(1c) than in its nonglycated analog. The glycation-induced structural modification of hemoglobin may be associated with its functional modification leading to oxidative stress in diabetic patients.
• 2.22

  Impact points

  In vitro nonenzymatic glycation enhances the role of myoglobin as a source of oxidative stress.

  Anjana Roy, Subhrojit Sen, Abhay Sankar Chakraborti

  Free radical research. 03/2004; 38(2):139-46.

  Metmyoglobin (Mb) was glycated by glucose in a non-enzymatic in vitro reaction. Amount of iron release from the heme pocket of myoglobin was found to be directly related with the extent of glycation. After in vitro glycation, the unchanged Mb and glycated myoglobin (GMb) were separated by ion exchan... [more] Metmyoglobin (Mb) was glycated by glucose in a non-enzymatic in vitro reaction. Amount of iron release from the heme pocket of myoglobin was found to be directly related with the extent of glycation. After in vitro glycation, the unchanged Mb and glycated myoglobin (GMb) were separated by ion exchange (BioRex 70) chromatography, which eliminated free iron from the protein fractions. Separated fractions of Mb and GMb were converted to their oxy forms -MbO2 and GMbO2, respectively. H2O2-induced iron release was significantly higher from GMbO2 than that from MbO2. This free iron, acting as a Fenton reagent, might produce free radicals and degrade different cell constituents. To verify this possibility, degradation of different cell constituents catalyzed by these fractions in the presence of H2O2 was studied. GMbO2 degraded arachidonic acid, deoxyribose and plasmid DNA more efficiently than MbO2. Arachidonic acid peroxidation and deoxyribose degradation were significantly inhibited by desferrioxamine (DFO), mannitol and catalase. However, besides free iron-mediated free radical reactions, role of iron of higher oxidation states, formed during interaction of H2O2 with myoglobin might also be involved in oxidative degradation processes. Formation of carbonyl content, an index of oxidative stress, was higher by GMbO2. Compared to MbO2, GMbO2 was rapidly autooxidized and co-oxidized with nitroblue tetrazolium, indicating increased rate of Mb and superoxide radical formation in GMbO2. GMb exhibited more peroxidase activity than Mb, which was positively correlated with ferrylmyoglobin formation in the presence of H2O2. These findings correlate glycation-induced modification of myoglobin and a mechanism of increased formation of free radicals. Although myoglobin glycation is not significant within muscle cells, free myoglobin in circulation, if becomes glycated, may pose a serious threat by eliciting oxidative stress, particularly in diabetic patients.
• 1.11

  Impact points

  Human papillomavirus infection among Indian mothers and their infants.

  Sarmistha Bandyopadhyay, Subhrojit Sen, Lakshmi Majumdar, Ramdas Chatterjee

  Asian Pacific journal of cancer prevention : APJCP. 4(3):179-84.

  OBJECTIVE: Several studies have demonstrated that infants can acquire human papillomavirus (HPV) infection at birth from their mothers. The aim of the present investigation was to determine prevalence of HPV infection among pregnant women and evaluate the extent of perinatal transmission of HPVs to ... [more] OBJECTIVE: Several studies have demonstrated that infants can acquire human papillomavirus (HPV) infection at birth from their mothers. The aim of the present investigation was to determine prevalence of HPV infection among pregnant women and evaluate the extent of perinatal transmission of HPVs to infants. METHODS: The study included 135 pregnant women and their infants. The polymerase chain reaction (PCR) was performed to detect HPV DNA in cervical cells of the women and buccal cells of the infants. RESULTS: HPVs detected were genotyped by PCR using type specific primers. HPV DNA was identified in 38 mothers (28.14%, 38/135) and 14 babies (10.37%, 14/135). The prevalence rate of HPV type 16 was highest both in HPV positive maternal (63.15%, 24/38) and baby samples (85.71%, 12/14). At birth, the frequency of HPV transmission from infected mothers to their infants was 18.42% (7/38). The proportion of infants with HPV infection delivered by cesarean section was 78.57% (11/14). CONCLUSION: Cesarean section was not found protective for infants against perinatal HPV transmission. Infection in the infants was cleared within one year. This is the first report of its kind from India.