Intracellular multiplication of leprosy-derived mycobacteria in Schwann cells of dorsal root ganglion cultures

Organized nerve cultures of dorsal root ganglia from neonatal mice were infected with Mycobacterium leprae, the causative agent of leprosy. A significant multiplication of the acid-fast bacilli was observed within the Schwann cell component of the culture. The growth of these bacilli was sensitive to antileprosy drugs and was not observed directly in bacteriological media. These organisms were brightly stained with the monoclonal antibody to phenolic glycolipid-I, a M. leprae-specific marker. The antigenic, pathogenic, and biochemical characteristics of this mycobacterium are under investigation.

Organized nerve culture. I. A technique to study the effect of M. leprae infection

Neonatal dorsal root ganglia were cultivated in vitro by the technique of Murray. Within a week bundles of organized nerve fibers containing proliferating Schwann cells in different phases of axon association and fibroblast cells destined to become peri- or endoneural cells were obtained, peri- or endoneural cells were obtained. Many of these nerve fibers were myelinated within 3-4 weeks. Such 1 or 2 week old cultures were inoculated with M. leprae, and bacilli were found in the cytoplasm of Schwann cells and fibroblasts, demonstrating that these cells are phagocytic in nature and that it is possible to infect them with M. leprae, Schwann cells, mostly in the free or early association phase, engulfed the bacilli, and this affected their further interaction with the axons and subsequent myelin synthesis.

Organized nerve culture. II. DNA synthesis in Schwann cells in the presence of M. leprae

Schwann cells that contain M. leprae fail to incorporate DNA precursor, indicating blockage of DNA synthesis. Such a block could lead to no proliferation of Schwann cells, an essential requirement for successful association with axons and consequent myelination.

Action of mitomycin C on testicular steroidogenesis and its probable mode of action in albino rats

Testicular steroidogenesis was determined by radioimmuno assay of serum testosterone and histochemical demonstration of the key steroidogenic enzyme (delta 5 3 beta hydroxysteroid dehydrogenase) activity in the Leydig cells after treatment with mitomycin C (mc), (500 microgram/kg, Bwt). In vivo experiments showed mc treatment causes a remarkable fall of serum testosterone level along with significant reduction in the weights of testis and sex accessories. In vitro studies resulted in a diminution in the delta 5 3 beta hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity in the section of the testis after addition of mc (100, 200 microgram/ml) in the incubation medium. The consideration of the above findings coroborated to the suggestion that mc reduced testicular steroidogenesis.

Haemodynamic effects of hypothalamic stimulation on skin and muscle venous beds

Twenty three points mainly located in the posterior hypothalamus were stimulated to study its effect on the pressures, flows and calculated segmental resistances of the skin and muscle venous beds of hind limbs in the dog. Stimulation of these points produced a uniform pattern of rise in pressures of the muscle veins consisting consisting of a steep rise during stimulation followed by a rapid decline to basal level on its cessation. Skin veins, on the other hand registered a gradual increase in pressure during stimulation followed by a secondary rise during post stimulatory period. Large veins of both muscle and skin exhibited comparatively smaller pressure increases than small vein. These pressure changes were accompanied by a similar marked rise in systemic arterial pressure. Out of 23 points, 21 points produced similar increases in the calculated resistances of skin and muscle veins. Two points produced greater increase of the skin vein resistance. Total venous resistance of the limb was therefore, raised by all the points stimulated. None of these points elicited any fall in the pressures or calculated resistances of either the muscle or skin venous bed. Muscle venous outflow always registered an increase while the skin venous outflow recorded either a small increase or decrease or at times no change during the hypothalamic stimulation. These findings demonstrate that hypothalamic stimulation can profoundly alter the haemodynamics of the hind limb venous beds and actively mobilize the post capillary venous sections of both skin and muscle venous beds.

Pentose phosphate pathway and testicular steroidogenesis in rats following oxythiamine treatment

Suppression of delta5-3beta-hydroxy steroid dehydrogenase (delta5-3beta-OHD) and glucose-6-phosphate dehydrogenase (G-6-P-D) activities along with concomitant stimulation of succinic dehydrogenase (SDH) activity were observed in the rat testicular tissues following treatment with oxythiamine HC1, an inhibitor of pentose phosphate pathway. The same treatment also resulted in an accumulation of cholesterol and ascorbic acid in the gland associated with a decrease in the weights of seminal vesicle and prostate. The results suggest a diminution in testicular steroid biogenesis following an alteration of pentose phosphate pathway.

Familial Brachydactyly in an Indian Family: A case report

Brachydactyly or short digit is a rare deformity involving fingers and toes. We present a rare family with 6 known members affected with similar pattern of brachydactyly, affecting only bilateral index fingers. The knowledge of this entity is important and a thorough clinical and radiological evaluation is mandatory for any patient with digital deformities. DOI: http://dx.doi.org/10.3126/jnps.v31i3.5364 J Nep Paedtr Soc 2011;31(3): 241-243