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Although in vitro and animal studies have shown that iron loading in pancreatic beta cells impairs insulin secretion, no human studies have documented the acute effects of oral iron on beta-cell insulin secretory capacity. In the present study, we determined beta-cell insulin secretory capacity at baseline and after a single oral dose of iron (ferrous sulphate, 120 mg elemental iron) in healthy male individuals.Fifteen healthy male volunteers underwent an oral glucose tolerance test (OGTT) to document baseline glucose tolerance and insulin secretion kinetics (baseline OGTT). One week later, the same subjects underwent a second OGTT, 2 h after an oral dose of ferrous sulphate (120 mg of elemental iron) (post-iron OGTT). Changes in disposition index, insulin secretion kinetics, glucose tolerance, insulin resistance, insulin clearance and iron-related parameters in serum were determined.Compared to baseline OGTT, the areas under the curve (AUC) for serum iron and transferrin saturation increased by 125% and 118%, respectively, in the post-iron OGTT. The disposition index decreased by 20% (p = 0.009) and the AUC for glucose concentrations increased by 5.7% (p 0.001) during the post-iron OGTT. The insulin secretion rate was marginally lower during the first hour (-3.5%, p = 0.63), but became significantly higher during the second hour (22%, p = 0.005) of the post-iron OGTT. Insulin resistance and insulin clearance rate were not affected by iron intake.The decrease in disposition index and glucose tolerance observed after the oral dose of iron points to an acute iron-induced impairment in pancreatic beta-cell insulin secretory capacity.

Unmerited authorship in research papers is widely acknowledged to constitute research misconduct. In different contexts, it has been called “gift”, “honorary”, or “guest” authorship. Although several attempts have been made to address the issue, it remains a significant problem in research. In this paper, we discuss accepted criteria that qualify a person to be an author on a research publication and define what constitutes “gift authorship”. We also look at the scenario in India and try to identify the circumstances that have fostered this practice in academia in the country. Finally, we discuss the adverse effects of this practice on the research enterprise as a whole, and possible remedial measures.

IntroductionAlthoughin vitroand animal studies have shown that iron loading in pancreatic beta-cells impaired insulin secretion, no human studies have documented the acute effects of oral iron on beta-cell insulin secretory capacity. In this study, we determined beta-cell insulin secretory capacity at baseline and after a single oral dose of iron (ferrous sulphate, 120 mg elemental iron) in healthy male individuals.MethodsFifteen healthy male volunteers underwent an oral glucose tolerance test (OGTT) to document baseline glucose tolerance and insulin secretion kinetics (baseline OGTT). One week later, the same subjects underwent a second OGTT, two hours after an oral dose of ferrous sulfate (120 mg of elemental iron) (post-iron OGTT). Changes in disposition index, insulin secretion kinetics, glucose tolerance, insulin clearance, and iron-related parameters in serum were determined.ResultsCompared to baseline OGTT, the areas under the curve (AUC) for serum iron and transferrin saturation increased by 125% and 118% respectively, in the post-iron OGTT. The disposition index decreased by 20% (p=0.009) and the AUC for glucose concentrations increased by 5.7% (pConclusionThe decrease in disposition index and glucose tolerance observed after the oral dose of iron points to an acute iron-induced impairment in pancreatic beta-cell insulin secretory capacity.

Increased body iron stores and inflammation in adipose tissue have been implicated in the pathogenesis of insulin resistance (IR) and type 2 diabetes mellitus. However, the underlying basis of these associations are unclear. In order to assess this, we studied how IR and associated inflammation in adipose tissue developed in the presence of increased body iron stores. Male hepcidin knock-out (Hamp1-/-) mice, which have increased body iron stores, and wild-type (WT) mice were fed a high-fat diet (HFD) for 12 and 24 weeks. Development of IR and metabolic parameters linked to this, insulin signaling in tissue, and inflammation and iron-related parameters in visceral adipose tissue were studied in these animals. HFD-feeding resulted in impaired glucose tolerance in both genotypes of mice. In response to the HFD for 24 weeks, Hamp1-/- mice gained less body weight and developed less IR than corresponding WT mice. This was associated with less lipid accumulation in the liver and decreased inflammation and lipolysis in the adipose tissue in the knock-out mice, than in the WT animals. Fewer macrophages infiltrated the adipose tissue in the knockout mice than in wild-type mice, with these macrophages exhibiting a predominantly anti-inflammatory (M2-like) phenotype. These observations suggest a novel role of hepcidin (central regulator of systemic iron homeostasis) in the development of inflammation in adipose tissue and insulin resistance, in response to a high-fat diet.CLINICAL PERSPECTIVESElevated body iron stores and inflammation in adipose tissue have been implicated in the pathogenesis of insulin resistance (IR) and type 2 diabetes mellitus. However, the underlying molecular mechanisms linking them are unclear.In response to high-fat diet (HFD)-feeding (to induce IR), mice that lacked hepcidin (Hamp1-/-) (and hence had elevated body iron stores) gained less body weight and developed less insulin resistance than wild-type (WT) mice. Inflammation and infiltration of macrophages into adipose tissue of HFD-fed Hamp1-/- mice were less than in WT mice, with the macrophages exhibiting an anti-inflammatory M2-like phenotype.These findings suggest a novel role of iron and hepcidin in HFD-induced inflammation in adipose tissue and development of insulin resistance. They raise the possibility that modulation of body iron may represent a potential way to inhibit these processes.

Background and aims The use of Friedewald's formula to calculate serum low-density lipoprotein cholesterol (LDL-C) is well-known to have limitations. A modification of it, in 2013, has been proposed to be superior. However, it was not known whether LDL-C values (calculated by the modified formula) meet laboratory performance criteria for their estimation. This study aimed to evaluate this. Methods and results LDL-C values were calculated for 129,821 lipid profiles, using both Friedewald's formula and its modified version. Kappa statistics and intra-class correlation coefficient (ICC) were used to determine degree of agreement between directly measured and calculated values for LDL-C. Bias and total percentage error of the values were calculated. LDL-C concentrations calculated by the modified formula showed a greater degree of agreement with directly measured values (kappa = 0.713) than those calculated by Friedewald's formula (kappa = 0.595). Both the formulae produced values with negative biases (−3.47 for the modified formula and −7.62 for Friedewald's formula) and total percentage errors above the recommended limit of 12% (15.57% for the modified formula and 21.77% for Friedewald's formula). ICC showed that values calculated by the modified formula showed a greater degree of agreement with directly measured values, across a range of LDL-C values. Conclusion Calculated LDL-C values, using the modified formula, showed better agreement with directly measured values, and less bias and percentage total error than those obtained by use of Friedewald's formula. However, the percentage total error with use of the modified formula exceeded the recommended limit for LDL-C.

Background Few patients with dysphagia because of stroke receive early palliative care (PC) to align treatment goals with their values, as called for by practice guidelines, particularly before enteral access procedures for artificial nutrition. Measures To increase documented goals of care (GOC) discussions among acute stroke patients before feeding gastrostomy tube placement. Intervention We undertook a rapid-cycle continuous quality improvement process with interdisciplinary planning, implementation, and performance review to operationalize an upstream trigger for PC referral prompted by the speech and language pathology evaluation. Outcomes During a six-month period, 21 patients underwent gastrostomy tube placement; 52% had preprocedure GOC discussions postintervention, with the rate of compliance increasing steadily from 13% (11/87, preintervention) to 100% (2/2) in the final two months. Conclusions/Lessons Learned We effectively increased documented GOC discussions before feeding gastrostomy tube placement among stroke patients. Systems-based tools and education will enhance this upstream trigger model to ensure early PC for stroke patients.

Clozapine is the drug of choice for treatment-resistant schizophrenia. However, its use is associated with variable clinical responses and serious adverse effects. Polymorphisms in genes encoding proteins involved in synaptic neurotransmission may account for such variability. Here, we studied independent and epistatic genetic associations of polymorphisms in DRD4 (120-bp duplication) and COMT (Val158Met) with clinical response to clozapine in people with treatment-resistant schizophrenia. We studied 93 participants who were on stable doses of clozapine for at least 12 weeks. A total score of less than or equal to 35 on the Brief Psychiatric Rating Scale was defined as a clinical response. The genetic associations were tested using logistic regression analyses. Neither polymorphism studied was found to be independently associated with response to clozapine. However, a statistically significant gene-gene interaction was observed between the polymorphisms. Participants with the COMT Val/Met or Met/Met genotype, who also had one or two DRD4 120-bp alleles (120/240 and 120/120), showed significantly better clinical response to clozapine. Our results highlight the importance of investigating gene-gene interactions, while studying the pharmacogenetics of clozapine.

Aim Diabetes mellitus has been reported to be associated with increased serum levels of ferritin. The basis of this association is unclear. It is also not precisely known whether other iron-related parameters, including hepcidin (the central regulator of systemic iron homeostasis), are affected under these circumstances. This study attempted to determine this. Methods Adult men (normoglycemic or newly diagnosed with diabetes or pre-diabetes) were recruited. Anthropometric, metabolic, and hematological and iron-related parameters in blood were measured. Indices of insulin resistance (HOMA-IR) and pancreatic beta cell function (HOMA-β) were calculated. Results Subjects in the 3 groups were similar in age, and anthropometric and hematological parameters. Serum ferritin and hepcidin levels were higher in diabetics, than in pre-diabetics and in control subjects. These elevations seen were not linked to the presence of inflammation. HOMA-IR was higher in diabetics, and HOMA-β lower in diabetics and pre-diabetics, than in control subjects. HOMA-IR and serum ferritin were positively correlated with one another. Conclusion Elevated levels of serum ferritin and hepcidin in newly diagnosed diabetics (but not pre-diabetics) indicate dysregulated iron homeostasis, with the former positively associated with insulin resistance in these patients.

Type 2 diabetes mellitus (T2DM) and insulin resistance (IR) have been associated with dysregulation of iron metabolism. The basis for this association is not completely understood. To attempt to investigate this, we studied temporal associations between onset of insulin resistance (IR) and dysregulated iron homeostasis, in a mouse model of T2DM. Male C57Bl/6 mice (aged 8 weeks) were fed a high-fat diet (HFD; 60% energy from fat) or a control diet (CD; 10% energy from fat) for 4, 8, 12, 16, 20 and 24 weeks. Development of IR was documented, and various metabolic, inflammatory and iron-related parameters were studied in these mice. HFD-feeding induced weight gain, hepato-steatosis and IR in the mice. Onset of IR occurred from 12 weeks onwards. Hepatic iron stores progressively declined from 16 weeks onwards. Accompanying changes included a decrease in hepatic hepcidin (Hamp1) mRNA expression and serum hepcidin levels and an increase in iron content in the epididymal white adipose tissue (eWAT). Iron content in the liver negatively correlated with that in the eWAT. Factors known to regulate hepatic Hamp1 expression (such as serum iron levels, systemic inflammation, and bone marrow-derived erythroid regulators) were not affected by HFD-feeding. In conclusion, the results show that the onset of IR in HFD-fed mice preceded dysregulation of iron homeostasis, evidence of which were found both in the liver and visceral adipose tissue.

Background Increased body iron stores have been implicated in the pathogenesis of diabetes mellitus. However, the molecular mechanisms involved are unclear. The liver plays a central role in homeostasis of iron and glucose in the body. Mice deficient in hepcidin (the central regulator of systemic iron homeostasis) (Hamp1−/− mice) accumulate iron in the liver in vivo. The effects of such iron loading on hepatic insulin signaling and glucose metabolism are not known. Methods Hepatocytes isolated from Hamp1−/− mice were studied for markers of insulin signaling (and its downstream effects), glucose production, expression of gluconeogenic and lipogenic enzymes, and markers of AMPK (AMP-activated protein kinase) activation and oxidative stress. These parameters were studied both in the absence and presence of insulin, and also with the use of an iron chelator. Results Akt in the insulin signaling pathway was found to be activated in the Hamp1−/− hepatocytes to a greater extent than wild-type (WT) cells, both under basal conditions and in response to insulin. Incubation of the Hamp1−/− hepatocytes with an iron chelator attenuated these effects. There was no evidence of oxidative stress or AMPK activation in the Hamp1−/− hepatocytes. Glucose production by these cells was similar to that by WT cells. Gene expression of key gluconeogenic enzymes was decreased in these cells. In addition, they showed evidence of increased lipogenesis. Conclusions Hepatocytes from Hamp1−/− mice showed evidence of greater sensitivity to the effects of insulin than WT hepatocytes. This may explain the insulin-sensitive phenotype that has been reported in classical hemochromatosis.

Background Perturbations in iron homeostasis have been reported to be associated with irreversible liver injury in chronic liver disease (CLD). However, it is not clear whether liver dysfunction per se underlies such dysregulation or whether other factors also contribute to it. This study attempted to examine the issues involved. Methods Patients diagnosed to have chronic liver disease (n = 63), who underwent a medically-indicated upper gastrointestinal endoscopy, were the subjects of this study. Patients with dyspepsia, who underwent such a procedure, and were found to have no endoscopic abnormalities, were used as control subjects (n = 49). Duodenal mucosal samples were obtained to study mRNA and protein levels of duodenal proteins involved in iron absorption. A blood sample was also obtained for estimation of hematological, iron-related, inflammatory and liver function-related parameters. Results Patients with CLD had impaired liver function, anemia of inflammation and lower serum levels of hepcidin than control subjects. Gene (mRNA) expression levels of duodenal ferroportin and duodenal cytochrome b (proteins involved in iron absorption) were decreased, while that of divalent metal transporter–1 (DMT-1) was unchanged. Protein expression of DMT-1 was, however, decreased while that of ferroportin was unchanged. In the CLD group, serum hepcidin was predicted independently by serum ferritin and hemoglobin, but not by C-reactive protein (a marker of inflammation). CLD patients with serum ferritin greater than 300 μg/dL had significantly greater liver dysfunction (as indicated by significantly higher serum concentrations of bilirubin, AST and ALT, and MELD scores), higher serum concentrations of CRP and hepcidin, and higher ferroportin protein expression, than those with serum ferritin ≤ 300 μg/dL. Conclusions In patients with CLD, anemia of inflammation and low serum hepcidin levels were found to paradoxically co-exist. Expression of duodenal proteins involved in iron absorption were either decreased or unaltered in these patients. The hepcidin response to higher body iron levels and/or inflammation appeared to be functional in these patients, despite the presence of liver disease.

Background An iron-overloaded state has been reported to be associated with insulin resistance. On the other hand, conditions such as classical hemochromatosis (where iron overload occurs primarily in the liver) have been reported to be associated with increased insulin sensitivity. The reasons for these contradictory findings are unclear. In this context, the effects of increased intracellular iron per se on insulin signaling in hepatocytes are not known. Methods Mouse primary hepatocytes were loaded with iron in vitro by incubation with ferric ammonium citrate (FAC). Intracellular events related to insulin signaling, as well as changes in gene expression and hepatocyte glucose production (HGP), were studied in the presence and absence of insulin and/or forskolin (a glucagon mimetic). Results In vitro iron-loading of hepatocytes resulted in phosphorylation-mediated activation of Akt and AMP-activated protein kinase. This was associated with decreased basal and forskolin-stimulated HGP. Iron attenuated forskolin-mediated induction of the key gluconeogenic enzyme, glucose-6-phosphatase. It also attenuated activation of the Akt pathway in response to insulin, which was associated with decreased protein levels of insulin receptor substrates 1 and 2, constituting insulin resistance. Conclusions Increased intracellular iron has dual effects on insulin sensitivity in hepatocytes. It increased basal activation of the Akt pathway, but decreased activation of this pathway in response to insulin. General significance These findings may help explain why both insulin resistance and increased sensitivity have been observed in iron-overloaded states. They are of relevance to a variety of disease conditions characterized by hepatic iron overload and increased risk of diabetes.

The clinical use of non-steroidal anti-inflammatory drugs (NSAIDs) is often associated with adverse effects in the kidney. Indomethacin, an NSAID that has been shown to induce oxidative stress in the kidney, was used to study the pathogenesis of renal damage induced by the drug in a rat model. Experimental animals were given indomethacin (20 mg/kg) by oral gavage, sacrificed 1, 12 or 24 h (h) later and the kidneys studied. Evidence of glomerular and tubular damage in the kidney was found in response to the drug. Renal tissue nitrite levels, a surrogate marker of nitric oxide (NO) synthesis, were significantly decreased at 12 and 24 h. Indomethacin did not affect protein and mRNA levels of endothelial nitric oxide synthase (eNOS) or inducible NOS (iNOS). However, it significantly reduced the ratio of dimeric (active) to monomeric (inactive) eNOS in the kidney, 12 and 24 h after drug administration. This was associated with reductions in heme content, both in renal tissue and in NOS. Heme oxygenase 1 (HO-1) mRNA (at 1 and 12 h), protein (at 12 and 24 h) and activity (at 1, 12 and 24 h) were elevated in response to indomethacin. Nuclear translocation of Nrf2 (at 12 h) and p38 MAPK signaling (at 12 h and 24 h), both of which are known to induce HO-1, also occurred in response to the drug. In summary, our results show that indomethacin reduced levels of activated eNOS in the kidney. This effect is possibly mediated by heme depletion, secondary to HO-1 induction that occurred downstream of Nrf2 and p38 MAPK signaling. We postulate that reduced renal eNOS activity may result in decreased NO levels, and hence reduced renal perfusion, leading to glomerular and tubular injury with subsequent renal damage.

ATOH8 has previously been shown to be an iron-regulated transcription factor, however its role in iron metabolism is not known. ATOH8 expression in HEK293 cells resulted in increased endogenous HAMP mRNA levels as well as HAMP promoter activity. Mutation of the E-box or SMAD response elements within the HAMP promoter significantly reduced the effects of ATOH8, indicating that ATOH8 activates HAMP transcription directly as well as through bone morphogenic protein (BMP) signalling. In support of the former, Chromatin immunoprecipitation assays provided evidence that ATOH8 binds to E-box regions within the HAMP promoter while the latter was supported by the finding that ATOH8 expression in HEK293 cells led to increased phosphorylated SMAD1,5,8 levels. Liver Atoh8 levels were reduced in mice under conditions associated with increased erythropoietic activity such as hypoxia, haemolytic anaemia, hypotransferrinaemia and erythropoietin treatment and increased by inhibitors of erythropoiesis. Hepatic Atoh8mRNA levels increased in mice treated with holo transferrin, suggesting that Atoh8 responds to changes in plasma iron. ATOH8 is therefore a novel transcriptional regulator of HAMP, which is responsive to changes in plasma iron and erythroid activity and could explain how changes in erythroid activity lead to regulation of HAMP.

ObjectivesDespite clozapine's superior clinical efficacy in treatment-resistant schizophrenia (TRS), its adverse effects, need for periodic leukocyte monitoring, cost and variable clinical outcomes mandate a clinical need to predict its treatment response. Although cytochrome P450 1A2 (CYP1A2) is the principal determinant of metabolism of clozapine, the role ofCYP1A2gene in the clinical response to clozapine is uncertain. Hence, we investigated its association with treatment responses and adverse events of clozapine in TRS.MethodsWe evaluated four single nucleotide polymorphisms (SNP) in theCYP1A2gene, clinical responses and serum clozapine levels in 101 consecutive patients with TRS on stable doses of clozapine. We defined clozapine responsea prioriand investigated allelic and genotypic associations. We assessed the socio-demographic and clinical profiles, premorbid adjustment, traumatic life events, cognition and disability of the participants, using standard assessment schedules for appropriate multivariate analyses.ResultsOur results revealed thatCYP1A2gene SNP (*1C, *1D, *1Eand*1F) were not associated with clozapine treatment response, adverse effects, serum clozapine levels or with disability (pvalues > 0.10).ConclusionAsCYP1A2gene SNP do not help to predict the clinical response to clozapine, routine screening for them prior to start clozapine is currently unwarranted. We suggest future longitudinal genome-wide association studies investigating clinical and pharmacogenetic variables together.

Hepatic Fe overload has often been reported in patients with advanced alcoholic liver disease. However, it is not known clearly whether it is the effect of alcohol that is responsible for such overload. To address this lacuna, a time-course study was carried out in mice in order to determine the effect of alcohol on Fe homoeostasis. Male Swiss albino mice were pair-fed Lieber–DeCarli alcohol diet (20 % of total energy provided as alcohol) for 2, 4, 8 or 12 weeks. Expression levels of duodenal and hepatic Fe-related proteins were determined by quantitative PCR and Western blotting, as were Fe levels and parameters of oxidative stress in the liver. Alcohol induced cytochrome P4502E1 and oxidative stress in the liver. Hepatic Fe levels and ferritin protein expression dropped to significantly lower levels after 12 weeks of alcohol feeding, with no significant effects at earlier time points. This was associated, at 12 weeks, with significantly decreased liver hepcidin expression and serum hepcidin levels. Protein expressions of duodenal ferroportin (at 8 and 12 weeks) and divalent metal transporter 1 (at 8 weeks) were increased. Serum Fe levels rose progressively to significantly higher levels at 12 weeks. Histopathological examination of the liver showed mild steatosis, but no stainable Fe in mice fed alcohol for up to 12 weeks. In summary, alcohol ingestion by mice in this study affected several Fe-related parameters, but produced no hepatic Fe accumulation. On the contrary, alcohol-induced decreases in hepatic Fe levels were seen and may contribute to alcohol-induced suppression of hepcidin.

Anemia of inflammation is characterized by disturbances in systemic iron homeostasis. In order to better understand the events involved, we carried out a time-course study on the effects of acute and chronic inflammation on iron-related proteins in mouse splenic macrophages and the liver. Mice were sacrificed at various time points ranging from 0 h up to 4 weeks after induction of inflammation with turpentine oil. Expression levels of iron-related proteins in the splenic macrophages and liver were determined. Iron levels in the serum, spleen and liver were also measured. Hepatic hepcidin was found to be induced in response to inflammation. In the macrophages, expression levels of ferroportin and TfR1 were decreased at some of the time points. The expression of hepatic TfR1 and ferritin was significantly higher at the early time points. Ferritin levels in the liver decreased progressively thereafter; this was associated with significantly higher ferroportin expression in the liver, despite high levels of hepcidin, suggesting that hepcidin may not regulate ferroportin levels in the liver, unlike in the macrophages. The effects of hepcidin, thus, appeared to be tissue-specific. Serum iron levels were decreased initially; these then rose and were associated with decreasing iron levels in the liver and spleen. Thus, inflammation affected the expression levels of many proteins involved in iron homeostasis in splenic macrophages and the liver, with differences seen in the effects at these 2 sites. These effects are likely to contribute to the development of anemia of inflammation.

The clinical utility of nonsteroidal anti-inflammatory drugs (NSAIDs) is often limited by the adverse effects that they produce in the small intestine. Alterations in the composition and functions of the glycocalyx and brush border membranes of the rat small intestine have been shown to occur in response to indomethacin, an NSAID often used in the study of adverse effects of these drugs. The micronutrient, zinc, has been documented to have cytoprotective effects in the gastrointestinal tract. The aim of this study was to evaluate the potential of zinc to reduce indomethacin-induced small intestinal damage. We pre-treated rats with zinc sulphate (50 mg/kg body weight) 2 h before administration of indomethacin (20 mg/kg body weight) and sacrificed the rats 1, 12 or 24 h after indomethacin. The extent of small intestinal mucosal damage and the content of lipids and sugars in the mucosa were determined. Bacterial counts in the intestinal lumen and the mucosa were ascertained. Activities of matrix metalloproteinases (MMPs) and levels of metallothionein in the mucosa were also measured. Pre-treatment with zinc sulphate was found to reduce the extent of indomethacin-induced mucosal damage. It also prevented drug-induced changes in the content of lipids and sugars in the mucosa. Drug-induced increases in activities of the MMPs and bacterial counts in the intestine were also attenuated by zinc. Metallothionein levels were significantly higher in animals pre-treated with zinc. We conclude that zinc was effective in protecting against indomethacin-induced small intestinal damage and suggest that it may do so by induction of metallothionein.

The clinical utility of non-steroidal anti-inflammatory drugs (NSAIDs) is limited by their gastrointestinal and renal toxicities. Indomethacin (an NSAID commonly used in toxicity studies) has been shown to induce significant oxidative stress and mitochondrial dysfunction in the rat kidney. The current study was designed to assess the potential of zinc, a known antioxidant, to protect the kidney against these drug-induced effects. Male Wistar rats were pre-treated with zinc sulphate (50 mg/kg) and dosed with indomethacin (20 mg/kg) by oral gavage. Rats were sacrificed 24 h after the dose of indomethacin. Parameters of oxidative stress, mitochondrial function and lipid content of the mitochondrial membranes were measured in the kidneys of these animals. It was found that zinc significantly attenuated indomethacin-induced oxidative stress, mitochondrial dysfunction and changes in the lipids in mitochondrial membranes in the kidney. The content of metallothionein, a cysteine-rich zinc-binding protein, was also determined in the tissue. There was no significant induction of metallothionein in the kidney in zinc-treated animals. Estimation of serum creatinine showed that zinc seemed to hasten functional recovery of the kidney following indomethacin administration. We conclude that pretreatment with zinc is effective in protecting against indomethacin-induced changes in the rat kidney. This protective effect does not appear to be mediated by metallothionein.

Biotinidase is an enzyme synthesized predominantly by the liver. Serum activity of this enzyme has been shown to be low in chronic liver disease. In this study, we endeavored to assess the diagnostic value of serum biotinidase as a marker of hepatic biosynthetic function in acute and chronic liver dysfunction. Twenty-three patients with acute liver disease and 46 with chronic liver disease, as diagnosed by clinical examination, laboratory tests, histopathology and tests for viral markers, were inducted into the study. Forty-six healthy volunteers were selected as controls. Serum biotinidase activity was estimated in all the subjects. Biotinidase activity was found to be significantly lower in the serum of patients with acute (4.59 ± 1.26 IU/L vs 7.56 ± 0.82 IU/L in controls; P≤ 0.001) and chronic (2.98 ± 1.18 IU/L vs 7.56 ± 0.82 IU/L in controls; P≤ 0.001) liver disease. Using receiver–operator characteristic curves, serum biotinidase was found to have high values of sensitivity and specificity when applied as a diagnostic test in both acute and chronic liver disease. These results suggest that serum biotinidase may be a sensitive and specific diagnostic marker of hepatic biosynthetic function in both acute and chronic liver disease.

In the course of our professional experience, we have seen that many medical students plagiarise. We hypothesised that they do so out of ignorance and that they require formal education on the subject. With this objective in mind, we conducted a teaching session on issues related to plagiarism. As a part of this, we administered a quiz to assess their baseline knowledge on plagiarism and a questionnaire to determine their attitudes towards it. We followed this up with an interactive teaching session, in which we discussed various aspects of plagiarism. We subjected the data obtained from the quiz and questionnaire to bivariate and multivariate analysis. A total of 423 medical students participated in the study. Their average score for the quiz was 4.96±1.67 (out of 10). Age, gender and years in medical school were not significantly associated with knowledge regarding plagiarism. The knowledge scores were negatively correlated with permissive attitudes towards plagiarism and positively correlated with attitudes critical of the practice. Men had significantly higher scores on permissive attitudes compared to women . In conclusion, we found that the medical students' knowledge regarding plagiarism was limited. Those with low knowledge scores tended to have permissive attitudes towards plagiarism and were less critical of the practice. We recommend the inclusion of formal instruction on this subject in the medical curriculum, so that this form of academic misconduct can be tackled.

Cirrhosis with ascites is associated with impaired renal function accompanied by sodium and water retention. Although it has been suggested that mediators such as nitric oxide play a role in the development of renal failure in this situation, other mechanisms underlying the process are not well understood. This study examined the role of oxidative stress in mediating renal damage during the development of cirrhosis in order to understand mechanisms involved in the process. It was shown that carbon tetrachloride- or thioacetamide-induced cirrhosis in rats results in oxidative stress in the kidney as seen by increased lipid peroxidation and protein oxidation, accompanied by altered antioxidant status. Cirrhosis was also found to affect renal mitochondrial function, as assessed by measurement of the respiratory control ratio, the swelling of mitochondria, and calcium flux across mitochondrial membranes. Increased lipid peroxidation and changes in lipid composition were evident in the renal brush border membranes, with compromised transport of 14 C glucose across these membranes. In conclusion, renal alterations produced as a result of cirrhosis in the rat are possibly mediated by oxidative stress.

Nonsteroidal anti-inflammatory drugs (NSAIDs) cause small intestinal damage but the pathogenesis of this toxicity is not well established. Our earlier work has shown that villus enterocytes are most susceptible to the effects of indomethacin, a commonly used NSAID. This study looked at the acute effect of indomethacin on brush border membranes (BBM), which are present mainly in the villus cells and are in immediate contact with the contents of the small intestinal lumen. Evidence of oxidative stress was found in the mucosa of the small intestine of rats dosed with indomethacin, as indicated by increased activity of xanthine oxidase with corresponding decrease in the levels of several free radical scavenging enzymes. These changes were associated with an increase in peroxidation parameters in the BBM and a fall in the level of alpha-tocopherol. These BBM also exhibited impairment in glucose transport. Significant changes were seen in the lipid composition of these membranes, with upregulation of an 85kDa isoform of phospholipase A(2). Pretreatment of animals with allopurinol, arginine or zinc protected against these effects of indomethacin. Thus this study suggests that in an acute model of indomethacin dosing there is impairment in structure and function of the BBM in enterocytes, with the effects possibly mediated by free radicals and phospholipases.

The use of clozapine, an effective antipsychotic drug used in treatment-resistant schizophrenia, is associated with adverse effects. Sialorrhea is one such effect, which can be distressing for many patients. Studies on the pharmacogenetics of the adverse effects of clozapine are limited. The aim of the present study was to determine whether clozapine-induced sialorrhea is associated with a 120 base-pairs (bp) tandem duplication polymorphism in the dopamine receptor subtype D4 (DRD4) gene. Ninety-five patients, mean age 35.43±9.43 years, with treatment-resistant schizophrenia and on clozapine were included in the study. Development of sialorrhea in response to the drug, as manifested by drooling of saliva, was documented in 45 (47.4%) patients. Genotyping of the patients was carried out to detect the presence of the polymorphism of interest. Clozapine-induced sialorrhea was found to be associated significantly with the 120-bp duplication in DRD4. The association was found to fit a log-additive model with an odds ratio of 2.95 (95% confidence interval 1.51–5.75; P=0.0006). Thus, the presence of the 120-bp duplication in DRD4 appears to confer a risk for sialorrhea in response to clozapine therapy. The underlying pathophysiology and clinical significance of this phenomenon warrant further investigation.

Background The pathogenesis of NSAID-induced gastrointestinal damage is believed to involve a nonprostaglandin dependent effect as well as prostaglandin dependent effects. One suggestion is that the nonprostaglandin mechanism involves uncoupling of mitochondrial oxidative phosphorylation. Aims To assess the role of uncoupling of mitochondrial oxidative phosphorylation in the pathogenesis of small intestinal damage in the rat. Methods We compared key pathophysiologic events in the small bowel following (i) dinitrophenol, an uncoupling agent (ii) parenteral aspirin, to inhibit cyclooxygenase without causing a 'topical' effect and (iii) the two together, using (iv) indomethacin as a positive control. Results Dinitrophenol altered intestinal mitochondrial morphology, increased intestinal permeability and caused inflammation without affecting gastric permeability or intestinal prostanoid levels. Parenteral aspirin decreased mucosal prostanoids without affecting intestinal mitochondria in vivo, gastric or intestinal permeability. Aspirin caused no inflammation or ulcers. When dinitrophenol and aspirin were given together the changes in intestinal mitochondrial morphology, permeability, inflammation and prostanoid levels and the macro- and microscopic appearances of intestinal ulcers were similar to indomethacin. Conclusions These studies allow dissociation of the contribution and consequences of uncoupling of mitochondrial oxidative phosphorylation and cyclooxygenase inhibition in the pathophysiology of NSAID enteropathy. While uncoupling of enterocyte mitochondrial oxidative phosphorylation leads to increased intestinal permeability and low grade inflammation, concurrent decreases in mucosal prostanoids appear to be important in the development of ulcers.

Background Myeloperoxidase (MPO) and interleukin-6 (IL-6) are often used as markers of inflammation. The aim of this study was to ascertain whether MPO activity is as reliable as IL-6 as an indicator of inflammation. Methods Inflammation was induced in mice, using either turpentine or indomethacin. Duodenal tissue was removed from these animals at various time periods ranging from 6 h to 7 days later. Concentrations of IL-6 and MPO activity were estimated in the tissue. Histopathological examination was also carried out at some of the time periods to determine the presence of neutrophil infiltration in turpentine-treated mice. Results Concentrations of IL-6 and MPO activity were significantly higher in tissue that had been treated with the agents used, at all the time periods studied, when compared with corresponding control tissue. Fold-increases in MPO activity were higher than fold-increases in IL-6. Concentrations of the 2 parameters showed significant positive correlation. Histopathological examination did not show significantly higher numbers of neutrophils infiltrating the tissue in response to turpentine, at the time periods studied. Conclusions Estimation of MPO activity is a reliable indicator of inflammation, being more sensitive than histopathological examination of tissue and as good as measurement of IL-6 concentrations.

The predicted gastrointestinal tolerability of specific cyclooxygenase-2 inhibitors could be due to either a lack of 'topical' irritation and/or lack of effect on cyclooxygenase-1.Key pathophysiologic steps (in vitro and in vivo uncoupling, intestinal prostanoid levels (prostaglandin E, thromboxane B2, and 6-keto-prostaglandin F1alpha), intestinal permeability (51Cr-ethylenediaminetetraacetic acid), inflammation (faecal excretion of a granulocyte marker protein), and ulcer counts) in enteropathy induced by nonsteroidal anti-inflammatory drugs were assessed after administration of indomethacin, 10 mg/kg, and 15 (roughly equipotent), 30, and 60 mg/kg of the preferential cyclooxygenase-2 inhibitor nimesulide.Indomethacin uncoupled oxidative phosphorylation at lower concentrations than nimesulide in vitro. Indomethacin was associated with electron microscopy changes suggestive of uncoupling in 60%-70% of enterocytes examined, whereas nimesulide affected 10%-30% of enterocytes, depending on the dose. Indomethacin increased intestinal permeability and caused inflammation and ulcers with 71%-96% reductions in prostanoid levels. Nimesulide at 15 mg/kg caused no damage, whereas 30 and 60 mg/kg nimesulide were associated with significant decreases in mucosal prostanoids (46%-75%), but only the 60-mg/kg dose caused a transient increase in intestinal permeability. However, at none of the doses did nimesulide cause intestinal inflammation or ulcers.These results endorse the idea that selective cyclooxygenase-2 inhibitors may be associated with some gastrointestinal tolerance due to their selectivity for cyclooxygenase-2, inhibiting cyclooxygenase-1 at only very high doses, and reduced topical irritation.

BACKGROUND: Nitric oxide derivatives of non-steroidal anti-inflammatory drugs (NSAIDs) are thought to be much less ulcerogenic than their parent compounds. AIM: To compare the effect and potency of flurbiprofen and nitroxybutyl-flurbiprofen to uncouple mitochondrial oxidative phosphorylation (an early pathogenic event in NSAID enteropathy), increase intestinal permeability (transitional stage), and cause macroscopic small intestinal damage. METHODS: In vitro uncoupling potency was assessed using isolated coupled rat liver mitochondria and in vivo by electron microscopy of rat small intestinal mucosa (two hours after the drugs). A dose-response study with flurbiprofen (single doses of 5, 10, 20, and 40 mg/kg) and equimolar doses of nitroxybutyl-flurbiprofen was performed; assessing their effect on intestinal permeability (at 18-20 hours), with 51Cr EDTA, and the number of pointed (< 5 mm) and longitudinal (> 5 mm) small intestinal ulcers at 24 hours. RESULTS: Flurbiprofen, but not nitroxybutyl-flurbiprofen, stimulated coupled respiration in vitro. Both drugs, however, uncoupled in vivo; in the case of nitroxybutyl-flurbiprofen possibly because hydrolysis of its ester bond released free flurbiprofen. Intestinal permeability was uniformly and equally increased with both drugs compared with controls. The number of small intestinal ulcers, pointed and longitudinal, was significantly reduced with nitroxybutyl-flurbiprofen apart from the number of longitudinal ulcers with the highest dose. CONCLUSIONS: These studies show that nitroxybutyl-flurbiprofen is associated with significantly less macroscopic damage in the small intestine than flurbiprofen but was associated with mitochondrial damage in vivo and caused similar increases in permeability of the small intestine, suggesting that its beneficial effect is on the later pathogenic stages of the damage.

Mechanisms responsible for derangements in Fe homeostasis in chronic inflammatory conditions are not entirely clear. The aim of the present study was to test the hypothesis that inflammation affects the expression of Fe-related proteins in the duodenum and monocytes of patients with chronic inflammatory disorders, thus contributing to dysregulated Fe homeostasis. Duodenal mucosal samples and peripheral blood monocytes obtained from patients with chronic inflammatory disorders, namely ulcerative colitis (UC), Crohn's disease (CD) and rheumatoid arthritis, were used for gene and protein expression studies. Hb levels were significantly lower and serum C-reactive protein levels were significantly higher in patients in the disease groups. The gene expression of several Fe-related proteins in the duodenum was significantly up-regulated in patients with UC and CD. In patients with UC, the protein expression of divalent metal transporter 1 and ferroportin, which are involved in the absorption of dietary non-haem Fe, was also found to be significantly higher in the duodenal mucosa. The gene expression of the duodenal proteins of interest correlated positively with one another and negatively with Hb. In patients with UC, the gene expression of Fe-related proteins in monocytes was found to be unaffected. In a separate group of patients with UC, serum hepcidin levels were found to be significantly lower than those in the control group. In conclusion, the expression of Fe-related proteins was up-regulated in the duodenum of patients with chronic inflammatory conditions in the present study. The effects appeared to be secondary to anaemia and the consequent erythropoietic drive.

Fixed oral doses of clozapine produce up to 45-fold interindividual variability among its serum levels in patients with treatment-resistant schizophrenia. Although the relationship between serum clozapine level and its therapeutic response is uncertain, the presence of a therapeutic window and level-dependent adverse effects require the estimation of serum clozapine levels. As routine therapeutic drug monitoring of clozapine is not feasible in many clinical settings, identification of clinical predictors of serum clozapine levels is desirable. Hence, we aimed to evaluate the clinical variables associated with serum clozapine levels. We assessed the sociodemographic and clinical profiles, cognition, disability and psychopathology of 101 consecutive patients with treatment-resistant schizophrenia on a stable dose of clozapine, using standard assessment schedules. We determined their serum clozapine levels using high-performance liquid chromatography with ultraviolet detection. While employing multivariate robust regression models, oral clozapine dose (P

Background E-learning resources (e-resources) have been widely used to facilitate self-directed learning among medical students. The Department of Biochemistry at Christian Medical College (CMC), Vellore, India, has made available e-resources to first-year medical students to supplement conventional lecture-based teaching in the subject. This study was designed to assess students’ perceptions of the impact of these e-resources on various aspects of their learning in biochemistry. Methods Sixty first-year medical students were the subjects of this study. At the end of the one-year course in biochemistry, the students were administered a questionnaire that asked them to assess the impact of the e-resources on various aspects of their learning in biochemistry. Results Ninety-eight percent of students had used the e-resources provided to varying extents. Most of them found the e-resources provided useful and of a high quality. The majority of them used these resources to prepare for periodic formative and final summative assessments in the course. The use of these resources increased steadily as the academic year progressed. Students said that the extent to which they understood the subject (83%) and their ability to answer questions in assessments (86%) had improved as a result of using these resources. They also said that they found biochemistry interesting (73%) and felt motivated to study the subject (59%). Conclusions We found that first-year medical students extensively used the e-resources in biochemistry that were provided. They perceived that these resources had made a positive impact on various aspects of their learning in biochemistry. We conclude that e-resources are a useful supplement to conventional lecture-based teaching in the medical curriculum.

Pharmacogenetics of schizophrenia has not yet delivered anticipated clinical dividends. Clinical heterogeneity of schizophrenia contributes to the poor replication of the findings of pharmacogenetic association studies. Functionally important HTR3A gene single-nucleotide polymorphisms (SNPs) were reported to be associated with response to clozapine.The aim of this study was to investigate how the association between HTR3A gene SNP and response to clozapine is influenced by various clinical predictors and by differing outcome definitions in patients with treatment-resistant schizophrenia (TRS).We recruited 101 consecutive patients with TRS, on stable doses of clozapine, and evaluated their HTR3A gene SNP (rs1062613 and rs2276302), psychopathology, and serum clozapine levels. We assessed their socio-demographic and clinical profiles, premorbid adjustment, traumatic events, cognition, and disability using standard assessment schedules. We evaluated their response to clozapine, by employing six differing outcome definitions. We employed appropriate multivariate statistics to calculate allelic and genotypic association, accounting for the effects of various clinical variables.T allele of rs1062613 and G allele of rs2276302 were significantly associated with good clinical response to clozapine (p = 0.02). However, varying outcome definitions make these associations inconsistent. rs1062613 and rs2276302 could explain only 13.8 % variability in the responses to clozapine, while combined clinical predictors and HTR3A pharmacogenetic association model could explain 38 % variability.We demonstrated that the results of pharmacogenetic studies in schizophrenia depend heavily on their outcome definitions and that combined clinical and pharmacogenetic models have better predictive values. Future pharmacogenetic studies should employ multiple outcome definitions and should evaluate associated clinical variables.

The BMP/SMAD4 pathway has major effects on liver hepcidin levels. Bone morphogenetic protein-binding endothelial cell precursor-derived regulator (Bmper), a known regulator of BMP signaling, was found to be overexpressed at the mRNA and protein levels in liver of genetically hypotransferrinemic mice (Trf(hpx/hpx)). Soluble BMPER peptide inhibited BMP2- and BMP6-dependent hepcidin promoter activity in both HepG2 and HuH7 cells. These effects correlated with reduced cellular levels of pSMAD1/5/8. Addition of BMPER peptide to primary human hepatocytes abolished the BMP2-dependent increase in hepcidin mRNA, whereas injection of Bmper peptide into mice resulted in reduced liver hepcidin and increased serum iron levels. Thus Bmper may play an important role in suppressing hepcidin production in hypotransferrinemic mice.

OBJECTIVE Early neurologic deterioration has been studied in patients with intracerebral hemorrhage during hospitalization, but rates and factors associated with prehospital neurologic deterioration (PND) are unknown. We sought to determine the prevalence of PND among patients with intracerebral hemorrhage during Emergency Medical Services transportation to the hospital. DESIGN Historical cohort study. SETTINGS U.S. acute care hospital from 2000 to 2004. PATIENTS Hospitalized patients with a diagnosis of spontaneous intracerebral hemorrhage were identified by codes of the International Statistical Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). METHODS The initial Glasgow Coma Scale score ascertained at the scene by the Emergency Medical Services was compared with the subsequent evaluation in the emergency department to identify neurologic deterioration (defined as a decrease in Glasgow Coma Scale of > or = 2 points). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Of the 98 patients with acute intracerebral hemorrhage, 22 patients (22%) showed PND during Emergency Medical Services transport, with a mean decrease in the Glasgow Coma Scale score during transport of 6 points. The patients who demonstrated neurologic deterioration tended to have higher diastolic blood pressure at the scene (p = .045), greater rates of intraventricular extension (p < .0001), and radiologic signs of herniation (p < .0001) on initial computed tomographic scan. There was a statistically significant decrease in diastolic blood pressure between the evaluations of the Emergency Medical Services and the emergency department among both patients with and without PND. CONCLUSIONS PND occurs in nearly one fifth of patients with intracerebral hemorrhage. Higher diastolic blood pressure at the scene, intraventricular extension, and radiologically evident herniation seem to be associated with PND. Prospective studies are needed to evaluate the efficacy of Emergency Medical Services interventions to reduce this early clinical deterioration.

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used in clinical medicine. Their utility is, however, often limited by the adverse effects they produce in the gastrointestinal tract. Oxidative stress has been shown to occur in the small intestine in response to the oral administration of indomethacin, an NSAID commonly used in toxicity studies. In view of this, the effect of curcumin, an agent with anti-oxidant properties, was evaluated on indomethacin-induced small intestinal damage in a rat model. Rats were pretreated with various doses of curcumin (20 mg kg(-1), 40 mg kg(-1) and 80 mg kg(-1)) before administering indomethacin at 20 mg kg(-1). Various parameters of oxidative stress and the extent of small intestinal damage produced by indomethacin, with and without pretreatment with curcumin, were measured. Macroscopic ulceration was found to occur in the small intestine in response to indomethacin. The viability of enterocytes from indomethacin-treated animals was significantly lower than those from control animals. Drug-induced oxidative stress was also evident as seen by increases in the levels of malondialdehyde and protein carbonyl and in activities of pro-oxidant enzymes such as myeloperoxidase and xanthine oxidase in indomethacin-treated rats. Concomitant decreases were seen in the activities of the antioxidant enzymes catalase and glutathione peroxidase in these animals. Pretreatment with curcumin was found to ameliorate these drug-induced changes. Thus, curcumin appears to hold promise as an agent that can potentially reduce NSAID-induced small intestinal damage.

Ingestion of non-steroidal anti-inflammatory drugs (NSAIDs) causes an enteropathy. The pathogenesis involves biochemical initiation of intestinal mucosal damage due to NSAID-induced inhibition of cyclooxygenase and the topical effects of these drugs. These effects lead to increased intestinal permeability and inflammation. Luminal bile acids play a controversial role in the damage produced by these drugs. The aim of this study was to determine the role of bile in producing the enteropathy caused by indomethacin, an NSAID commonly used in toxicity studies. Sprague-Dawley rats were subjected to bile duct ligation. Twenty-four hours later, they were dosed with indomethacin. Intestinal permeability ((51)Cr-EDTA) and inflammation (faecal calprotectin) were measured in the animals at various time periods after the dose. Intestinal permeability was significantly higher in rats 1-6 h after dosing with indomethacin, but not at 24-29 h or day 4, when compared with corresponding values for control animals. Excretion of faecal calprotectin was elevated in the indomethacin-treated rats. The drug-treated animals showed no evidence of ulceration when they were sacrificed 29 h or a week after the dose of indomethacin. Bile acids per se did not affect intestinal permeability or faecal excretion of calprotectin, when given along with indomethacin or its vehicle. We conclude that macroscopic small bowel damage does not occur with indomethacin if bile is excluded, despite the induction of permeability and inflammation. This study highlights the importance of luminal factors, such as bile, in producing indomethacin-induced ulceration in the rat small intestine.

To determine the feasibility and safety of treatment of acute hypertension in patients with intracerebral hemorrhage within 24 hrs of symptom onset. Elevated blood pressure, observed in up to 56% of patients with intracerebral hemorrhage, may predispose to hematoma expansion; on the other hand, reduction of blood pressure may reduce hematoma expansion and subsequent death and disability.Single-center prospective registry supplemented by retrospective chart review.University-affiliated medical center with dedicated stroke service.All patients admitted to the stroke service with spontaneous intracerebral hemorrhage and acute hypertension within 24 hrs of symptom onset.Patients were treated with intravenous nicardipine within 24 hrs of symptom onset to reduce and maintain mean arterial pressure of130 mm Hg. The mean arterial pressure goal was consistent with the American Heart Association guidelines.The primary outcome was the tolerability of the treatment as assessed by achieving and maintaining the mean arterial pressure goals for 24 hrs after initiation of intravenous nicardipine infusion. Other end points ascertained were: neurologic deterioration defined by a decline in Glasgow Coma Scale from pretreatment assessment byor=2 points or increase in National Institutes of Health Stroke Scale score byor=2 points and hemorrhage growth defined as an increase in the volume of intraparenchymal hemorrhage of33% as measured by image analysis on the 24-hr computed tomographic scan compared with the baseline computed tomographic scan. Rates of favorable outcome and death were ascertained at 1 month. Of the total 46 patients admitted with intracerebral hemorrhage in our service, 29 patients were treated. Mean age of the treated patients was 58 +/- 13 yrs; ten were women. Initial National Institutes of Health Stroke Scale ranged from 1 to 38. The primary outcome of tolerability was achieved in 25 of the 29 patients (86%). Neurologic deterioration was observed in 4 of 29 patients. Hematoma enlargement was observed in five patients. Favorable outcome (defined as modified Rankin scale ofor=2) and death at 1-month was observed in 11 (38%) and 9 (31%) of the 29 patients, respectively.We observed a high rate of tolerability among patients with intracerebral hemorrhage who were treated with intravenous nicardipine using mean arterial pressure goals defined by American Heart Association guidelines within 24 hrs of symptom onset.

Objectives: To study the pattern of excretion of enzymes in urine during normal pregnancy. Design and methods: Primigravidae, with uncomplicated pregnancies, were followed up throughout gestation. Urine samples were collected from them and activities of alanine aminopeptidase (AAP), gamma-glutamyl transferase (GGT), acid phosphatase (ACP) and N-acetyl-beta- d -glucosaminidase (NAG) activities in urine were estimated. Results: Small but significant increases were found in the activities of AAP and NAG excreted through the course of pregnancy. The changes seen in excretion of ACP and GGT were not statistically significant. Conclusions: Changes in excretion of ACP and GGT may be useful indicators of renal dysfunction in pregnancy, as their activities did not vary significantly through the course of normal pregnancy.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used extensively in clinical medicine. One disadvantage of their use, however, is the occurrence of adverse effects in the kidneys. The side effects produced in this organ have been classically attributed to the inhibitory effect of these drugs on the activity of cyclooxygenase, a key enzyme in prostaglandin synthesis. Our earlier work with indomethacin, a commonly used NSAID, has shown that oxidative stress and mitochondrial dysfunction occur in the kidney in response to the drug. In view of this, this study looked into the effect of indomethacin on brush border membranes (BBM) from the kidney, as these biomembranes are prime targets of oxygen free radicals. Rats, fasted overnight, were dosed with indomethacin (20 mg/kg) by gavage and sacrificed 24 h later. BBM were isolated from the kidneys by polyethylene glycol precipitation. It was found that there was an increase in levels of products of peroxidation and a fall in the level of alpha-tocopherol in the BBM from indomethacin-dosed rats. These BBM also exhibited impaired glucose transport. The lipid composition of the membranes was also found to be altered. Alterations in lipids were associated with up-regulation of phospholipase A2. Pretreatment with L-arginine, a nitric oxide donor, protected against these effects of indomethacin. Thus, this study suggests that indomethacin induces impairment in structure and function of BBM in the kidney, with these effects possibly mediated by free radicals and activation of phospholipases. We postulate that such alterations may be important in the pathogenesis of NSAID-induced nephropathy.

The use of NSAIDs (non-steroidal anti-inflammatory drugs), although of great therapeutic value clinically, is limited by their tendency to cause mucosal damage in the gastrointestinal tract. In the small intestine, the effects these drugs have been shown to produce include inhibition of cyclo-oxygenase, mitochondrial dysfunction and free radical-induced oxidative changes, all of which contribute to the mucosal damage seen. Glutamine is a fuel preferentially used by enterocytes and is known to contribute to maintaining the integrity of these cells. In the present study, we investigated the effect of glutamine on indomethacin-induced changes in the small intestinal mucosa. Rats were given 2% glutamine or glutamic acid or isonitrogenous amino acids, glycine or alanine, in the diet for 7 days. Indomethacin was then administered orally at a dose of 40 mg/kg of body weight. After 1 h, the small intestine was removed and used for the measurement of parameters of oxidative stress and mitochondrial and BBM (brush border membrane) function. Evidence of oxidative stress was found in the mucosa of the small intestine of drug-treated rats, as indicated by significantly increased activity of xanthine oxidase (P

Nonsteroidal anti-inflammatory drugs are used extensively in clinical medicine. In spite of their therapeutic utility, however, they are known to cause significant gastrointestinal and renal toxicities, circumstances that limit their use. The side effects produced in these organs have been attributed mainly to the inhibitory effect of these drugs on the activity of cyclooxygenase, a key enzyme in prostaglandin synthesis. In addition to this, in the small intestine it is known that reactive oxygen species also contribute to the enteropathy seen in response to these drugs. In the kidney, however, there is little information whether other mechanisms contribute to the renal toxicity. This study was designed to look at the possible biochemical mechanisms involved in indomethacin-induced renal damage. Rats fasted overnight were dosed with indomethacin (20 mg/kg) by gavage and sacrificed 24 hr later. Histology of the kidney showed abnormalities in the mitochondria in the proximal tubules. Evidence of oxidative stress was found in the kidney associated with mitochondrial dysfunction and neutrophil infiltration. The lipid composition in the mitochondria was also altered. Such effects were abolished by the prior administration of arginine, a donor of nitric oxide. This study, thus, suggests that one of the mechanisms by which nonsteroidal anti-inflammatory drugs induce renal damage is through oxygen free radicals possibly generated by activated neutrophils and mitochondrial dysfunction.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to cause small intestinal damage but the pathogenesis of this toxicity is not well established. Intestinal epithelial cells are thought to be affected by these drugs in the course of their absorption. These cells are of different types, viz. villus, middle and crypt cells. There is little information on which of these cells, if any, are particularly vulnerable to the effects of NSAIDs. This paper aimed to study the effects of indomethacin, an NSAID commonly used in toxicity studies, on different populations of enterocytes. Effects of the drug were assessed in terms of oxidative damage, mitotic activity, mitochondrial function and lipid composition in enterocytes isolated from the small intestine of rats that had been orally administered indomethacin. In addition, the effects of arginine and zinc in protecting against such changes were assessed. Cell viability, tetrazolium dye (MTT) reduction and oxygen uptake were significantly reduced in villus tip cells from rats dosed with the drug. Thymidine uptake was higher in the crypt cell fraction from these rats. Similarly, products of lipid peroxidation were elevated in the villus tip cells with a corresponding decrease in the level of the anti-oxidant, alpha-tocopherol. In isolated mitochondrial preparations from various enterocyte fractions, significant functional impairment and altered lipid composition were seen mainly in mitochondria from villus cells. Arginine and zinc pre-treatment were found to protect against these effects. These results suggest for the first time that the villus tip cells are more vulnerable to the damaging effects of indomethacin and that oxidative stress is possibly involved in this damage.

The non-steroidal anti-inflammatory drugs (NSAIDs) are a widely used group of drugs in clinical medicine. However, their propensity to cause gastrointestinal damage limits their clinical utility. The pathogenesis of this toxicity is not well established. It has been postulated that an early event in the development of damage is an effect of these drugs on mitochondrial function. The present paper sets out to evaluate the effects of indomethacin, a commonly used NSAID, on energy metabolism in vivo. Indomethacin was administered to male Sprague-Dawley rats, either intrajejunally or orally, and indices of mitochondrial function were determined. The parameters chosen for this purpose were oxygen uptake by, lactate levels in and the energy charge of jejunal tissue. Oxygen uptake by and energy charge in jejunal tissue were unaffected at 1 and 3h after dosing by gavage with indomethacin. The drug significantly affected the tissue lactate/pyruvate ratio at 3h (but not at 1h) after oral dosing. Effects of indomethacin on jejunum incubated ex vivo were found to be reversible. The data suggest that indomethacin affects mitochondrial function in vivo, but that compensatory changes in glycolytic rate maintain energy charge.