Arvind K.N. Nandedkar

Prenatal antiepileptic drug exposure alters seizure susceptibility in rats

An animal model is used to address the issue of prenatal exposure to certain antiepileptic drugs and seizure susceptibility in the offspring. Administration of doses established as median therapeutic doses in humans of phenobarbital, valproate and clonazepam to pregnant rats during the last third of gestation produced sexually dimorphic alterations in pentylenetetrazol (PTZ)-induced seizures as well as in non-convulsive (spontaneous alternation and cliff avoidance) behaviors in the offspring. Altered seizure susceptibility occurred in the absence of overtly recognizable morphological abnormalities and did not appear to reflect differences in the status of circulating drug-binding plasma proteins. Possible neural and/or metabolic mechanisms responsible for these behavioral changes are discussed.

Co++ binding by plasma proteins

Abstract 50Co++ added to human or rabbit plasmain vitro combines selectively with the albumin fraction. At pH 7.1, the Scatchard plot yields a curve that may be resolved for two classes of sites: one, wheren1 = 2 andK1 = 6.5 × 103, the other wheren2 = 23 andK2 = 1.6 × 102, Mn++ cannot compete for these sites. The affinity for the cobaltous ion displays a steep increment between pH 6.7 and 8.6. If injected intravenously 50% of the cobalt tracer is cleared from the plasma in 25 minutes. An additional complex of higher molecular weight than that of albumin is formedin vivo.

Affinity of osteogenin, an extracellular bone matrix associated protein initiating bone differentiation, for concanavalin A

Subcutaneous implantation of demineralized bone matrix results in bone differentiation. The bone inductive protein, osteogenin, was isolated recently by heparin affinity chromatography. The affinity of osteogenin for various lectins was examined to attain further purification and characterization. Osteogenin extracted from bovine bone matrix binds to concanavalin A (Con A) but not to wheat germ agglutinin or soybean lectin. The present data indicate that the bone inductive protein, osteogenin, is a glycoprotein. The use of a Con A Sepharose affinity column followed by preparative gel electrophoresis resulted in a greater than 250,000 fold purification of osteogenin.

Newborn thyroxine levels and childhood ADHD

OBJECTIVES Normal brain development is highly dependent on adequate levels of iodine and thyroid hormone. It has been suggested that Attention Deficit Hyperactivity Disorder (ADHD) is the consequence of prenatal thyroidal endocrine disruption. The hypothesis was examined using neonatal thyroxine levels as a bio-marker of prenatal thyroid status and comparing it to subsequent development of ADHD. DESIGN AND METHODS In a matched case-control study, cases were defined as children diagnosed with ADHD, while children born in the same hospital and tested on the same day served as matched controls. Conditional logistic regression analysis with unequal numbers of controls was performed. RESULTS The neonatal thyroxine levels were within normal limits for each of the children who were subsequently diagnosed as having ADHD, and their distribution was no different from that of their controls. CONCLUSIONS Children diagnosed with ADHD do not demonstrate prenatal thyroidal dysfunction as reflected in the newborn thyroxine levels, therefore neonatal thyroxine levels are not a bio-marker for the subsequent development of ADHD.

Co2+ binding by plasma albumin

Abstract 60Co introduced into the blood circulation of rabbits is bound mainly by an albumin-monomer and to a smaller extent by an albumin-dimer. The dimer cannot be converted into the monomer by exposure to a reducing agent. Immunoelectrophoresis and affinity chromatography confirm the existence of the albumin-dimer.

Biosynthesis of phosphatidyl ethanolamine in Mycobacterium 607

Abstract In Mycobacterium 607 (M. 607) streptomycin appears to inhibit the formation of phosphatidyl ethanolamine (PE) and polyglycerol phosphatide (PGP), by approximately 35%, as can be seen by 32P incorporation studies. PE is the only phosphatide containing nitrogenous base and is present in pathogenic, nonpathogenic and saprophytic species of mycobacteria. Incorporation of -14C of ethanolamine-1-14C into ethanolamine phosphate (EP) and PE, demonstration that, this incorporation is absolutely dependent on the presence of diglyceride (DG) and cytidine triphosphate (CTP), occurrence of the enzymes glycerolkinase and phosphatidic acid phosphatase and the absence of phosphatidyl serine (PS) decarboxylase strongly suggest that, in M. 607 the biosynthesis of PE is accomplished via CDP-ethanolamine mediated pathway.

Effect of experimental anaphylaxis on tissue lipids in rabbits

Abstract The changes in fatty acid composition of brain, spleen, and serum lipids in rabbits during fatal anaphylaxis have been investigated. As was surmised in an earlier report, the serum cholesterol content is found to be increased. However, increase in the phospholipids was unexpected. Overall, tissues seem to have increased amounts of unsaturated fatty acids at the expense of saturated ones.

Report on the utilization of ethanolamine-1-14C by Mycobacterium 607

Abstract Ethanolamine utilization by cell-free extracts of M 607 reveals that the 14C of ethanolamine-1-14C is incorporated into glycine, serine and alanine. The proposed pathway for the formation of these components is closer to bacterial systems. However, the formation of ethanolamine phosphate suggests its role as an intermediate in the biosynthesis of phosphatidyl-ethanolamine, a major nitrogen-containing phosphatide.