Biomedical subjects
Publications and source records attributed to R Mukherjee.
A case of facial palsy with lagophthalmos with exposure keratitis was corrected surgically by a method of temporalis transfer. When the slings were tightened leaving 1 cm gap in the palpebral aperture, lagophthalmos persisted. A secondary tightening procedure causing overlap of the upper lid over the lower yielded good results.
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A dot-enzyme linked immunosorbent assay (dot-ELISA) for the detection of antibodies in bovine brucellosis using soluble antigens extracted from Brucella abortus S-99 is described in which antigen was deposited on a nitrocellulose sheet (0.5 x 0.5 cm) bound to a plastic strip and the unsaturated sites blocked by a solution of spray-dried milk powder. Sera were tested at dilutions of 1:800 and 1:1600, using rabbit anti-bovine-immunoglobulin or protein-A coupled to peroxidase as conjugates and diamino-benzidine as substrate. A positive reaction was clearly indicated by a brown dot on the nitrocellulose sheet. Using antigen-coated, pre-blocked strips, the test could be completed within 45 minutes.
The interaction between M. leprae-infected cultured Schwann cells and sensitized splenic cells was noted both under light and electron microscopy. No evidence of cytomorphological changes in infected Schwann cells was obtained. However, sensitized splenic cells were noted to undergo degenerative changes suggestive of the phenomenon of apoptosis. Subsequently a large number of these degenerated cells were observed within the Schwann cell. Such a process has not been hitherto reported in the histopathology of leprous nerves. Nevertheless, these findings indicate an aberrant metabolic function in M. leprae-infected Schwann cells.
Bisnordihydrotoxiferine, a dimeric tertiary indole alkaloid obtained from the root bark of Strychnos trinervis (Vell.) Mart. (Loganiaceae), inhibited normal defaecation and castor oil, arachidonic acid, and magnesium sulphate-induced diarrhoea on intraperitoneal administration in mice. The effect may be related to the ability of the compound to decrease normal and castor oil-stimulated gastric emptying, small intestinal transit and water and electrolyte accumulation, and inhibition of normal colonic transit. As prostaglandins are involved in gastrointestinal functions, inhibition of their synthesis is likely to contribute to the anticathartic activity, which has never been reported before for an indole alkaloid.
The mechanism by which 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) inhibits transcription of the beta-major Hb gene in vivo was investigated in differentiated Friend erythroleukemic cells (FELC). Steady-state nuclear RNA from untreated and DRB-treated FELC was analyzed by the S1 nuclease assay using [32P]DNA probes labeled at their 3' end close to the site of transcription initiation. DRB severely inhibited transcription of full-length beta-major Hb mRNA precursor molecules and did not increase the production of short, promoter-proximal transcripts. In addition, nascent beta-major RNA transcripts were labeled with [alpha-32P]UTP in nuclei isolated from DRB-treated FELC and untreated FELC and hybridized to separate restriction fragments spanning the entire beta-major Hb gene. DRB inhibited transcription of the promoter-proximal and promoter-distal beta-Hb DNA restriction fragments uniformly by 75-80% and did not detectably increase the amount of short transcripts. Moreover, a brief reversal of the DRB inhibition in vivo increased the number of short, nascent, promoter-proximal beta-Hb transcripts apparently as a result of reinitiation. These data indicate that DRB inhibited transcription of the beta-major Hb gene in vivo at initiation.
Bisnordihydrotoxiferine has been isolated as the major alkaloid from the root bark of Strychnos trinervis. This compound shows a wide antimicrobial spectrum against gram-positive, gram-negative and acid-fast microorganisms, filamentous and yeast-like fungi and also phytopathogenic microorganisms. Preliminary studies also reveal some cytotoxic activity in KB cells which was confirmed by tests against sarcoma 180 tumors.
Adherence of Mycobacterium leprae was studied in vitro in monolayer cultures of purified mouse Schwann cells. The optimum temperature and time for adherence were determined. Pretreatment of Schwann cells with lipase reduced adherence, but pretreatment with trypsin enhanced it and with four monosaccharides--L-arabinose, L-galactose, L-rhamnose and D-glucose--there was no significant effect, indicating that the receptors involved in adherence may be lipid.
The patterns of microbial mineralization of 0.3 to 30 ng of glucose, benzoate, and phenol per ml of sewage collected in late fall and winter were analyzed with the integrated Monod equation and a model in which growth of active organisms occurs at the expense of organic compounds other than the test substrate. Either model could be closely fit by nonlinear regression to the data from individual tests with one concentration of substrate added to one dilution of sewage. However, neither model accounted satisfactorily for differences in patterns of mineralization resulting from differences in substrate concentration and cell density between different tests. It is suggested that both the added substrates and other organics present in sewage contributed to the growth of the active organisms. The mineralization of glucose in sewage collected in summer was better described by a two-compartment model than by any other model tested.
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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.
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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.