Mammalian microRNA: an important modulator of host-pathogen interactions in human viral infections

MicroRNAs (miRNAs), which are small non-coding RNAs expressed by almost all metazoans, have key roles in the regulation of cell differentiation, organism development and gene expression. Thousands of miRNAs regulating approximately 60æ% of the total human genome have been identified. They regulate genetic expression either by direct cleavage or by translational repression of the target mRNAs recognized through partial complementary base pairing. The active and functional unit of miRNA is its complex with Argonaute proteins known as the microRNA-induced silencing complex (miRISC). De-regulated miRNA expression in the human cell may contribute to a diverse group of disorders including cancer, cardiovascular dysfunctions, liver damage, immunological dysfunction, metabolic syndromes and pathogenic infections. Current day studies have revealed that miRNAs are indeed a pivotal component of host-pathogen interactions and host immune responses toward microorganisms. miRNA is emerging as a tool for genetic study, therapeutic development and diagnosis for human pathogenic infections caused by viruses, bacteria, parasites and fungi. Many pathogens can exploit the host miRNA system for their own benefit such as surviving inside the host cell, replication, pathogenesis and bypassing some host immune barriers, while some express pathogen-encoded miRNA inside the host contributing to their replication, survival and/or latency. In this review, we discuss the role and significance of miRNA in relation to some pathogenic viruses

Effectiveness of seminar as an educational tool among the undergraduate medical students: A study

Background: The faculty of medical colleges have a greater responsibility in making the study methods of their subject innovative, interesting and participatory for the under graduate students. One such method is organizing seminars for the undergraduate students. Objective: To assess effectiveness of student seminars as a teaching learning method in the undergraduate medical curriculum. Methods: This study was conducted in the Department of Biochemistry, Malla Reddy Institute of Medical Sciences, Hyderabad on a group of 150 students. This study assesses the role of seminar as teaching-learning tool by recording the effectiveness and perception of medical students on seminars through a pre-test/post-test evaluation and questionnaire-based survey. Results: A highly significant improvement (p<0.001) was observed among the medical students after the seminar sessions based on pretest and posttest analysis. 85% of the students reported that they found the seminars to be an interesting method of gaining knowledge. 78% of them felt seminars could be a good associated T/L method along with didactic lectures. 88% felt they got to learn new things from their peers in the seminar group. All the students who presented were of the opinion that seminar improved their communication skills, learned to make a formal scientific presentation and gained self-confidence after presenting the seminar. Conclusion: Seminars can be used as effective teaching learning method in the medical curriculum for a better understanding and outcome among the medical students

Assessment of erythrocyte SOD activity in different stages of Essential Hypertension patients

Oxidative stress has been found to be associated with most of the diseases. In the past several years, much interest has arisen over the involvement of free radical metabolism in the disturbance in endothelial or intimal cells of blood vessels, which play an important role in the pathogenesis of essential hypertension (HT). Although limited information is available on the activity of antioxidant enzyme erythrocyte superoxide dismutase (SOD) and its relation with blood pressure in patients with HT, alteration in their activity with severity of disease is still obscure. The objective of present study was to estimate the activity of SOD in hypertensive subjects and to determine the variation in erythrocyte SOD activity with increasing blood pressure. In the present study, erythrocyte SOD activity was measured in 90 hypertensive subjects (30-60 years) which were categorized into three groups as pre-hypertension, stage I HT and stage II HT (depending upon their blood pressure) and statistically compared it with that of 30 healthy individuals, served as control. Erythrocyte SOD activity was found to be significantly low in each patient group as compared to control (P<0.001). These activities were also low among three groups of essential hypertension. These findings suggest that depletion in erythrocyte SOD activity with subsequent rise in blood pressure is due to its superoxide anion scavenging action against hypertension induced production of free radical in the body. Thus, erythrocyte SOD activity may be an effective marker of oxidative stress in different stages of essential hypertension and its related complications

Thyroid Status in Relation to Age and Gender - A Cross Sectional Study

Background: Thyroid disorders have become much more common in the present days and so are its resultant complications or sequelae. There are marked variations in thyroid function with age and sex, evident in all of the in vitro hormone and protein measurements. Objective: To correlate the thyroid status with age and gender. Methods: 500 subjects of all age group and both genders from the general population of Bagalkot, Karnataka were included in the study. Subjects suffering from thyroid disorders were excluded. Non-Fasting venous samples were collected from all the subjects, serum T3, T4, and TSH levels were estimated by microplate immunoenzymometric assay. Statistical analysis was done by ANOVA and unpaired ‘t’ test. Results: It was observed that T3 and T4 levels declined but TSH levels raised, as the age advanced. T3 and T4 levels were lower and TSH levels higher in female subjects as compared to male subjects, in the age group of 21 – 40 years. Conclusion: The variability in the thyroid status has to be borne in mind during evaluation and treatment of thyroid disorders

GATA6 coordinates cross-talk between BMP10 and oxidative stress axis in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by a progressive increase in pulmonary vascular resistance leading to right ventricular failure and often death. Here we report that deficiency of transcription factor GATA6 is a shared pathological feature of PA endothelial (PAEC) and smooth muscle cells (PASMC) in human PAH and experimental PH, which is responsible for maintenance of hyper-proliferative cellular phenotypes, pulmonary vascular remodeling and pulmonary hypertension. We further show that GATA6 acts as a transcription factor and direct positive regulator of anti-oxidant enzymes, and its deficiency in PAH/PH pulmonary vascular cells induces oxidative stress and mitochondrial dysfunction. We demonstrate that GATA6 is regulated by the BMP10/BMP receptors axis and its loss in PAECs and PASMC in PAH supports BMPR deficiency. In addition, we have established that GATA6-deficient PAEC, acting in a paracrine manner, increase proliferation and induce other pathological changes in PASMC, supporting the importance of GATA6 in pulmonary vascular cell communication. Treatment with dimethyl fumarate resolved oxidative stress and BMPR deficiency, reversed hemodynamic changes caused by endothelial Gata6 loss in mice, and inhibited proliferation and induced apoptosis in human PAH PASMC, strongly suggesting that targeting GATA6 deficiency may provide a therapeutic advance for patients with PAH