Cadherins and catenins at synapses: roles in synaptogenesis and synaptic plasticity

Synapse formation involves reciprocal interactions between cells resulting in formation of a structure optimized for efficient information transfer. Recent work has implicated constituents of the cadherin-catenin cell-adhesion complex in both synapse formation and plasticity. In this review, we describe recent interesting discoveries on mechanisms of cadherin complex function, in addition to regulating adhesion, that are relevant for understanding the role of this complex in synaptogenesis and plasticity. We describe how this complex acts via (i) recruitment/stabilization of intracellular partners; (ii) regulation of intracellular signaling pathways; (iii) regulation of cadherin surface levels, stability and turnover; (iv) stabilization of receptors; and (v) regulation of gene expression. These exciting discoveries provide insights into novel functional roles of the complex beyond regulating cell adhesion.     

Dietary adequacy of Indian children residing in an urban slum--analysis of proximal and distal determinants

The influences of proximal and distal determinants of dietary adequacy of children from an urban slum in India were analyzed. Children numbering 271 (5-14 years) and their mothers were enrolled for the study. Intake of all nutrients except protein was inadequate in the dietaries of children. Among distal determinants, associations were found between (i) calorie intake and maternal nutritional status; (ii) protein, iron and B-complex intakes and economic status, and (iii) retinol, calcium and fat intakes and family size. Literacy status was not associated with dietary adequacy. Age of children and economic status of family were important determinants of dietary adequacy of children from slum area.     

Maternal and neonatal profile and immediate outcome in ELBW babies

The present study was designed to ascertain the maternal and neonatal profile and immediate outcome of extremely low birth weight (ELBW) babies at a Level III neonatal intensive care unit (NICU). Case records of ELBW inborn babies delivered between August 2000 and August 2001 were analyzed by using a preset proforma. A total of 52 ELBW babies were admitted in NICU in the relevant period, out of which 30 (57%) survived. Maternal anemia and previous pre-term (PT) delivery were the common predisposing factors for PT delivery. Mean gestational age was 27.8 weeks and mean birth weight was 831 grams. Mortality was highest in babies less than 28 weeks gestation. Neonatal hyper-bilirubinemia (78%) and HMD/RDS (65%) were the commonest morbidity. Retinopathy of Prematurity (ROP) screening could be done in 35 babies (68%), out of which 22 were found to be normal.     

Iron deficiency alters iron regulatory protein and iron transport protein expression in the perinatal rat brain

Iron plays an important role in numerous vital enzyme systems in the perinatal brain. The membrane proteins that mediate iron transport [transferrin receptor (TfR) and divalent metal transporter 1 (DMT-1)] and the iron regulatory proteins (IRP-1 and IRP-2) that stabilize their mRNAs undergo regional developmental changes in the iron-sufficient rat brain between postnatal day (P) 5 and 15. Perinatal iron deficiency (ID) affects developing brain regions nonhomogeneously, suggesting potential differences in regional iron transporter and regulatory protein expression. The objective of the study was to determine the effect of perinatal ID on regional expression of IRP-1, IRP-2, TfR, and DMT-1 in the developing rat brain. Gestationally iron-deficient Sprague Dawley rat pups were compared with iron-sufficient control pups at P10. Serial 12-mu coronal sections of fixed frozen brain from pups on P10 were assessed by light microscopy for IRP-1, IRP-2, DMT-1, and TfR localization. ID did not change the percentage of cells with positive staining for the four proteins in the choroid epithelium, ependyma, vascular endothelium, or neurons of the striatum. ID increased the percentage of neurons expressing the four proteins in the hippocampus and the cerebral cortex. Increased numbers of TfR- and DMT-1-positive cells were always associated with increased IRP-positive cells. The P10 rat responds to perinatal ID by selectively increasing the number of neurons expressing IRP-regulated transporters in brain regions that are rapidly developing, without any change at transport surfaces or in regions that are quiescent. Brain iron distribution during ID seems to be locally rather than globally regulated.     

Certain pesticide-induced carbohydrate metabolic disorders in the serum of freshwater fish Clarias batrachus (Linn.).

A freshwater edible catfish, Clarias batrachus (Linn.), was exposed to sublethal concentrations of two different groups of pesticides-carbaryl, a carbamate and phorate, an organophosphorus (OP) pesticide-for 24, 72, 120 and 168 hours. The alterations and the disorders of carbohydrate metabolism were studied in the serum. Serum glucose, alkaline phosphatase and bilirubin levels increased with both the pesticides throughout the exposure period. The results indicate that the carbohydrate metabolism was adversely affected by both the pesticides, as evidenced in the serum of the fish.     

Gender disparity in COVID-19: Role of sex steroid hormones

The emerging pandemic of COVID-19 caused by the novel pathogenic human coronavirus SARS-CoV-2 has caused significant morbidity and mortality across the globe, prompting the scientific world to search for preventive measures to interrupt the disease process. Demographic data indicates gender-based differences in COVID-19 morbidity with better outcome amongst females. Disparity in sex-dependent morbidity and mortality in COVID-19 patients may be attributed to difference in levels of sex steroid hormones-androgens and estrogens. Evidence suggests that apart from the regulation of viral host factors, immunomodulatory and cardioprotective roles exerted by estrogen and progesterone may provide protection to females against COVID-19. Exploring the underlying mechanisms and beneficial effects of these hormones as an adjuvant to existing therapy may be a step towards improving the outcomes. This article aims to review studies demonstrating the role of sex steroidal hormones in modulating SARS-CoV-2 host factors and summarize plausible biological reasons for sex-based differences seen in COVID-19 mortality.     

Case series of scleral patch grafts during COVID-19 pandemic

Scleral graft is done for clinical conditions as scleral melt post pterygium surgery, immune or infection related scleral melt, for covering the tubes of Ahmed glaucoma valve implant, for covering the orbital implants post enucleation, etc. A review of literature revealed the use of sclera for corneal perforations in the past, but became obsolete after the cornea being used for patch grafts. Now in this COVID-19 time, due to scarcity of corneal tissue, this technique of scleral patch grafts can be considered as an alternative to corneal patch grafts, which serves well the tectonic/therapeutic purpose and helps salvage the eye.     

Poor cognitive task performance of insulin-dependent diabetic children (6–12 years) in India

Cognitive function was assessed in 22 diabetic and 39 healthy children, all in the age group of 6–12 years. Wechsler's coding, digit span test and Raven's colored progressive matrices were included in the battery of tests. The diabetic children underscored on all these tasks compared to the healthy children. The raw scores (mean ± S.D.), of the diabetic and healthy children were: Wechsler's coding: 17.4 ± 6.48, 37.4 ± 9.33; digit span: 22.0 ± 8.8, 44.1 ± 7.67 and on Raven's A + A_B + B: 16.2 ± 3.5. 24.1 ± 6.26; P < 0.001 in each instance, respectively. Duration of diabetes did not correlate with any of the test scores. No significant differences were noted between the early onset (IDDM starting before the age of 5 years) and late onset (IDDM starting after 5 years) diabetic children in their performance. We attribute the very low scores in our diabetic children to the psycho-social factors in addition to the metabolic control. Conclusions: (1) specific cognitive dysfunction is present in children with IDDM compared to the healthy children; (2) duration of diabetes did not correlate with cognitive function scores; (3) IDDM manifesting after the age of 5 years also had hitherto unknown detrimental effects on the cognitive process.