Bidhan Chandra Koner

An evaluation of level of oxidative stress and protein glycation in nondiabetic undialyzed chronic renal failure patients.

BACKGROUND Chronic renal failure (CRF) patients on prolonged dialysis and with diabetes have been found to have significant alteration in their antioxidant status and protein glycation, but little is known about the same in nondiabetic undialyzed CRF patients. This study was performed to evaluate (a) the levels of oxidative stress and protein glycation in nondiabetic undialyzed CRF patients and (b) the possible influence of oxidative stress on protein glycation. DESIGN AND METHODS A case control study was performed on 23 nondiabetic undialyzed CRF patients and 17 control subjects. The concentrations of total plasma ascorbic acid, whole blood reduced glutathione (GSH) and plasma lipid peroxides were measured to evaluate the antioxidant status and oxidative stress. The protein glycation was measured from plasma fructosamine normalized for albumin concentrations. A partial correlation analysis was carried out to analyze the effect of oxidative stress parameters on protein glycation. RESULTS A compromised nonenzymatic defense against free-radical generation was evidenced by decreased concentrations of whole blood GSH and plasma ascorbic acid. The concentrations of lipid peroxides, fructosamine and fructosamine/albumin ratio were significantly (p<0.05) higher in the CRF group when compared with controls. The partial correlation analysis revealed that oxidative stress influences protein glycation in CRF patients. CONCLUSIONS Increased oxidative stress might have a role in promoting protein glycation in nondiabetic undialyzed CRF patients. The reduction of oxidative stress and protein glycation might open new therapeutic approaches in treating CRF patients.

Level of sialic acid residues in platelet proteins in diabetes, aging, and Hodgkin's lymphoma: a potential role of free radicals in desialylation.

The present study evaluated the levels of sialic acid and carbonylation in platelet proteins from diabetes, old age, and Hodgkins lymphoma cases and explored the role of free radicals in desialylation. Sialic acid and carbonylation were estimated in platelet suspension obtained from 10 healthy adult control subjects, 20 elderly healthy persons, 20 cases with diabetes, and 10 with Hodgkins lymphoma. The level of sialic acid residues in platelets was found to be significantly lower and the carbonylation of proteins was higher in old age, diabetes, and lymphoma cases in comparison to controls. The level of carbonylation correlated with desialylation in these cases. In vitro treatment of platelets with free radicals was found to cause desialylation and to increase the carbonyl content. Addition of 2-mercaptoethanol, an antioxidant, significantly attenuated the above effects. The study indicates the possible role of free radicals in desialylation of platelet proteins in the above clinical conditions.

Altered malondialdehyde, protein carbonyl and sialic acid levels in seminal plasma of microscopically abnormal semen

Microscopically abnormal (n = 26) semen showed significantly higher levels of malondialdehyde (MDA), protein carbonyl (PC) and protein‐bound sialic acid (SA) in seminal plasma as compared with normal semen (n = 24). The percentage of nonmotile spermatozoa showed significant (P < 0.01) positive correlation with MDA (r = 0.5) and PC (r = 0.49). Sperm counts showed a significant negative correlation with MDA (r = −0.63, P < 0.001) level of seminal plasma. SA correlated (r = 0.56, P < 0.01) with MDA. The receiver operating characteristic (ROC) curve of MDA and SA showed that MDA of 3.15 μmol l−1 and SA of 3.85 μmol l−1 were optimum cut‐off limits to discriminate abnormal semen from normal. In conclusion, high SA might be a protective response against prevailed oxidative stress in abnormal semen. Seminal plasma MDA and SA may act as potential markers of abnormal semen.

Activation of NF-κB in lymphocytes and increase in serum immunoglobulin in hyperthyroidism : Possible role of oxidative stress

This study evaluated oxidative stress, serum IgM and IgG, and nuclear factor (NF)-kappaB signaling in lymphocytes of hyperthyroidism patients. GSH content in lymphocytes was significantly lower and serum malondialdehyde, IgM and IgG levels were significantly higher in hyperthyroidism as compared to controls. In lymphocytes, the NF-kappaB signaling pathway was studied by western blot analysis of p65 and p-IkappaBalpha. Density of p-IkappaBalpha and p65 (in nuclear fraction) was significantly higher in hyperthyroidism as compared to controls. The density of p-IkappaBalpha and p65 had significant positive correlation with serum malondialdehyde level and negative correlation with lymphocyte GSH level in hyperthyroid cases. The serum IgG and IgM levels were correlated significantly with density of p-IkappaBalpha and p65. As immunoglobulin production is regulated by the NF-kappaB pathway, we conclude that the oxidative stress-induced activation of the NF-kappaB pathway might play a role in the rise of serum immunoglobulin level in hyperthyroidism.

Formulation of questions followed by small group discussion as a revision exercise at the end of a teaching module in biochemistry

Undergraduate medical students get fewer opportunities to clarify their doubts and to reinforce their understanding of concepts after lecture classes. There is no information available in the literature that addresses the question of usefulness of prior formulation of questions followed by small group discussion by undergraduate medical students as a revision exercise. The purpose of this work is to evaluate the effect of formulation of objective type short answer questions by undergraduate medical students followed by small group discussion on the answers of the questions prepared as a revision exercise on their understanding of the topic “amino acid metabolism” and the retention of the gain after 15 days. At the end of a regular teaching module on the topic of amino acid metabolism, undergraduate medical students were asked to prepare 16 objective type short answer questions on the various aspects of the topic as homework. Small group discussions involving 12–14 students in each group and lasting one hour were conducted on the questions and answers prepared by them in the presence of a faculty member. The effects on low, medium, and high achievers were evaluated with multiple choice questions by pre‐test and post‐tests before and after the group discussion. Formulation of questions was highly effective in improving understanding on the topic for all the students. The overall mean post‐test scores after the formulation of questions (12.6) and after the small group discussion that followed (14.7) were significantly higher than the mean pre‐test score (8.5). For high achievers, the gain from formulation of questions was higher than the gain from small group discussion. Small group discussion was highly effective for all students. The gain from small group discussion was higher among the low and medium achievers in comparison with the high achievers. The gain from the exercise was retained among the low, medium, and high achievers after 15 days. In conclusion, formulation of short answer questions followed by small group discussion on the answers of the questions prepared by the undergraduate medical students is an effective revision exercise for improving their understanding on a selected topic.

Conventional teaching remains effective in teaching medical biochemistry in BPKIHS, Nepal, although students enjoy supplementary computer teaching

A computer program down loaded from the Internet was used as a tutorial to teach the structure‐function relationship of MHC molecule to MBBS students of BPKIHS, a medical college in Nepal. The computer‐aided teaching session, with a facilitator from the biochemistry faculty, was found to be more interesting to the students although learning outcomes were not enhanced by comparison to sessions using only conventional tools. A non‐subject expert presenting the computer tutorial failed to generate interest in the topic, and the achievement of learning objectives by the students was inferior. We conclude that the interaction with a biochemistry subject expert was crucial for success in our use of computer‐aided teaching sessions on the structure‐function relationship of proteins. The results are discussed with attention to the role of computer‐aided instruction in medical colleges in a developing country (Nepal).

Effect of Restraint Stress Duration on Humoral Immune Response in Albino Rats: Modulation by Chlordiazepoxide

We evaluated the effect of restraint stress (1hr/day) for 6, 10, 14 and 21 days on antibody response against sheep RBC (SRBC) and modulation by chlordiazepoxide (CDP) pretreatment (10 mg/kg/day) in albino rats. Anti-SRBC titer was significantly decreased with increase in number of days of restraint stress exposure. CDP pretreatment significantly reversed the effects of 6, 10 and 14 (but not of 21) days of restraint stress. CDP treatment for 21 days per se suppressed immune response, but no additive effect was observed. CDP was not effective in chronic stress (i.e., 21 days of stress). Hence, the rationale behind benzodiazepines therapy in chronic stress needs to be evaluated.

Acute intermittent porphyria: Diagnosis per chance

OBJECTIVES To report a case of acute intermittent porphyria (AIP) diagnosed by chance during routine investigations. CLINICAL PRESENTATION AND INTERVENTION A 21-year-old female presented with vague gastrointestinal symptoms. Upon admission, she was disoriented. Later she developed generalized seizures and was treated with phenytoin, but the condition worsened. Upon investigation, her liver function, renal function, blood sugar level and electrolytes were within normal limits. When kept for routine laboratory testing, the color change in urine prompted us to investigate for porphyria. It was positive for phorphobilinogen (PBG) and urophorphyrin. Since AIP had been diagnosed, the initial treatment with phenytoin was discontinued with a favorable outcome. A screening test for PBG in urine by Ehrlichs reagent was performed on the patients mother and was positive. CONCLUSION A high degree of suspicion at the laboratory can also determine the diagnosis of AIP, which is often missed by the clinician.

Can quiz-contest be used in classroom teaching for undergraduate medical students?

Background: Revision exercises (RE) are the review sessions, commonly used for difficult topics in undergraduate medical training to improve the understanding of the students. Controlled discussions (CD) or lectures are the usual teaching-learning (T-L) methods used in RE.

Effect of acute and chronic stress on leucocyte count: modulation by chlordiazepoxide

Total and differential leucocyte count (TLC and DLC) in blood circulation influence humoral immune response and stress alters TLC and DLC by leucocyte misdistribution. Chlordiazepoxide, a widely used benzodiazepine anti-stress agent, is reported to reverse suppression of antibody response induced by acute stress but not by chronic stress. The effect of chlordiazepoxide on the changes in leucocyte count by acute and chronic stress has not been clearly defined. We examined the effect of restraint stress (1 h/day) for 6, 10, 14 and 21 days on TLC and DLC and their modulation by chlordiazepoxide pretreatment (10 mg/kg/day) 1 h before exposure to stress in albino rats. Acute stress, i.e. restraint stress (1 h/day) for 6 and 10 days with or with out chlordiazepoxide pretreatment did not alter TLC and DLC. Chronic stress, i.e. restraint stress (1 h/day) for 14 and 21 days significantly decreased TLC and the percentage of lymphocytes in comparison to control. Pretreatment with chlordiazepoxide reversed these changes. We conclude that chlordiazepoxide, a benzodiazepine, reverses changes in TLC and DLC probably by improving chronic stress-induced leucocytes misdistribution.