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Biomedical subjects

A N Chakrabarty

Publications and source records attributed to A N Chakrabarty.

At least 55 records · Page 3Linked to original sources
PubMed1989

Correlation between occurrence of leprosy and fossil fuels: role of fossil fuel bacteria in the origin and global epidemiology of leprosy.

On the basis of correlative data on the global distribution of leprosy, its bacteria metabolizing fossil fuels (FF), and the FF themselves, the origin of leprosy in the world as a whole, and in the leprosy-free countries, in particular, as indigenous cases, appeared to be primarily due to a soil-to-man, and secondarily due to a man-to-man infection. These findings helped to elucidate similar problems of animal leprosies and nocardial diseases.

Animals↗
PubMed1989

Drug interaction of promethazine & other non-conventional antimicrobial chemotherapeutic agents.

The antihistamine compound promethazine (Pz) showed significant antibacterial action when tested against 124 strains of aerobic and 13 strains of anaerobic bacteria belonging to both Gram positive and Gram negative genera. The range of MIC (micrograms/ml) of Pz varied between 50 and 200 micrograms/ml among most of the test organisms. Six Pz-sensitive strains were found to be simultaneously sensitive to similar non-conventional antimicrobics, e.g., methdilazine, bromodiphenhydramine, diphenhydramine, methyl-DOPA, promazine and the antibiotic augmentin. A high degree of synergism was observed in vitro when Pz was used in combination with methdilazine and bromodiphenhydramine.

Anti-Bacterial Agents↗
PubMed1989

Experimental studies on membrane permeability defects of drug-resistant bacteria.

Multiply antibiotic-, lysozyme-and bacitracin-resistant, representative strains of staphylococci, Escherichia coli, Shigella dysenteriae and Klebsiella pneumoniae were compared respectively with their parent cultures in respect of their membrane permeability as judged by fluorescence polarization spectroscopy, using a sensitive fluorescent probe. The cytoplasmic membrane of the drug-resistant mutants was found to be less fluid and permeable, compared to that from the sensitive wild types. The study constitutes an attempt to determine the physical basis for the mechanism of resistance of certain bacteria against certain drugs.

Bacitracin↗
PubMed1988

Antimicrobial properties of methdilazine and its synergism with antibiotics and some chemotherapeutic agents.

The antihistamine methdilazine (Md) was found to possess a significantly high antibacterial action when tested against 367 strains of bacteria belonging to both Gram-positive and Gram-negative genera. Different groups of bacteria could be arranged in order of their decreasing sensitivity towards Md as follows: S. aureus, V. cholerae, E. coli and Shigella. The range of minimum inhibitory concentration (micrograms/ml) varied between 25 and 200 in most cases, although few strains were sensitive even at 10 micrograms/ml level of Md. 10 different bacteria sensitive to Md and a number of antibiotics when tested for their interaction with Md on one hand and any of the antibiotics of chemotherapeutic agents on the other, it was found that Md in combination with aminoglycosides and several chemotherapeutics showed enhancement of antibacterial effects resulting in synergism. The chemotherapeutic agents bromodiphenhydramine (Bn), diphenhydramine and methyldopa showed distinct synergism when tested in combination with Md. Determination of the area of inhibition zones for the degree of synergism with Md and streptomycin (Sm) produced statistically significant result (p less than 0.01) in comparison with their individual effect. This could also be corroborated by the fractional inhibitory concentration (FIC) index which was 0.49 for Sm-Md and 0.5 for Bn-Md combinations. The synergism of Sm-Md combination was confirmed by in vivo studies.

Animals↗
PubMed1983

Immunochemical studies on a polysaccharide from Shigella dysenteriae type 2.

The polysaccharide isolated from Shigella dysenteriae type 2, strain NCTC 566, on Smith degradation and graded hydrolysis yielded three oligosaccharides which were characterised using methylation studies. Using homologous rabbit antiserum and the monosaccharides that constituted the polysaccharide and the oligosaccharides isolated from it and the cross-reactions in some type-specific pneumococcal antisera, immunochemical specificities of different sugar groupings in the polysaccharide molecule were determined. These results indicated that N-acetylglucosamine was the immunodominant sugar in the polysaccharide and the oligosaccharide isolated from the Smith-degraded product and having the structure (formula; see text) gave maximum inhibition of the specific precipitation.

Chemical Phenomena↗