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C V Bapat

Publications and source records attributed to C V Bapat.

33 records · Page 2Linked to original sources
PubMed1974

The inhibition of arginase by proline in cell-free extracts of mouse mammary tumour.

Arginase activity was found to be increased in precancerous nodules and mammary tumour when compared with the mammary gland. Proline inhibited the mammary tumour arginase and up to 30 mmo1 concentration the inhibition follows first order kinetics. Hill analysis of the inhibition of arginase by proline showed that proline inhibits the arginase activity by competing directly at the active site without conformational change. The inhibition may be of regulatory importanec, involving a feedback mechenism in mammary tumours.

Acetone↗
PubMedDate not supplied

Culture and phagocytic characteristics of Schwann cells in vitro. A possible model substrate for cultivation of M. leprae.

Tissue cultures of five acoustic and four spinal schwannomas demonstrated good growth and migration of Schwann cells within two to four days. Two types of cells corresponding to Antoni type A tissue and Antoni type B tissue were clearly recognized. Both these cell types showed avid phagocytosis when the cultures were inoculated with mycobacteria, either ICRC bacilli or M. leprae. The phagocytic index was 95% at the end of two hours. The Schwann cells grown in vitro also showed intense acid phosphatase reaction with Gomori's stain, suggesting lysosomal activity. Neither this nor any phagocytosis was evidenced by fetal fibroblasts cultured similarly. Cells from two spinal neurofibromas grew and migrated slowly in vitro and were mainly fibroblasts.

Cells, Cultured↗
PubMedDate not supplied

Comparison of biochemical characterisation of ICRC bacilli with M. leprae: effect of substrate alteration in the medium.

ICRC-bacilli strain C-44 when grown in Dubos medium of its equivalent, express M. avium taxonomic biochemical characters. Assuming that difference in characters of M. leprae and ICRC bacilli, could be due to 'in vivo' and 'in vitro' milieu, we altered the substrates in the medium. The bacilli grow well in the new medium containing selenium, ferric nitrate, magnesium chloride and deleting Tween 80. The ICRC strain C-44 grown in new medium expressed characters: 9/10 similarity with M. leprae. The 10 day tween hydrolysis reaction in weak but positive. It is probable that 'M. leprae culture isolate', may have acquired 'in vitro' growth potential by recombination with M. avium, an ubiquitous mycobacterium. The M. leprae culture isolate thus may express some characters of both M. leprae and M. avium.

Culture Media↗
PubMedDate not supplied

Antigeneic cross-reactivity between ICRC-bacilli and M. leprae--"in vitro" evaluation.

Leucocyte migration inhibition, in presence of specific particulate antigen, is a good correlate of CMI. It can detect small differences in related antigens. In the present study, LMI was used to study the cross-reactivity between ICRC bacilli and M. leprae and also to examine the antigenic relationship amongst different ICRC isolates. The study showed a close antigenic cross-reactivity in lepromin and ICRC-in. LMI has brought out strain differences in two ICRC culture isolates, C-44 and C-75. The data appear to elucidate the possible strain specific antigenic relationship of M. leprae with its culture isolate e.g. ICRC strains. This may have important bearing on the development effective antileprosy vaccine for human use.

Animals↗
PubMedDate not supplied

Induction of delayed-type hypersensitivity by ICRC anti-leprosy vaccine and the adoptive transfer of cell-mediated immunity in mice.

The immunogenic potency of anti-leprosy ICRC vaccine preparations was determined by foot pad enlargement in mice. Female Balb/c mice were sensitized by I.D. route with irradiated, heat-killed or live antigens of 2 strains (C-44 and C-75) of ICRC bacilli and tested against lepromin and ICRC-antigens. ICRC antigens sensitized mice against lepromin; similarly, BCG and M. leprae sensitized mice, which showed good cross reactivity with ICRC antigens. A mixture of irradiated ICRC bacilli and live BCG was not more immunogenic to mice than its single constituents. The immunity induced by ICRC antigens could be adoptively transferred to syngeneic recipients by sensitized spleen cells.

Animals↗
PubMedDate not supplied

Dopa-oxidase activity on ICRC bacilli.

Presence of O-phenoloxidase is regarded as M. leprae specific character. This enzyme activity was found to be present in ICRC bacilli, Strain C-44. Though this strain is cultivable 'in vitro', the expression of DOPA-Oxidase activity strongly suggests that it carries M. leprae genome. The ICRC bacilli, therefore, may thus from a group of M. leprae culture isolates, distinct from other known cultivable mycobacteria which do not possess this enzyme activity.

Catechol Oxidase↗
PubMedDate not supplied

Immunological properties of M. leprae culture isolates ICRC bacilli: hypothesis on relationship between M. leprae and ML-culture isolates.

The M. leprae-culture isolate, being a culture, is identified by biochemical criteria. Majority belong to either M. avium-intracellulare-scrofulacieum complex, or corynobacterium group. The identification is also determined by serological methods using soluble sonicates. Skin tests with heat-killed suspension often give positive Mitsuda response and hence the isolates are discarded as non-M. leprae. The data on ICRC strains show that Dharmendra type antigen prepared from ICRC bacilli compares very well with lepromin in lepromatous patients. The CMI/DTH tests in mice by FPE and LMI technique have experimentally demonstrated that ICRC bacillus is the first cultivable mycobacterium that can sensitize mice against lepromin. These data also brought out antigenic differences between the ICRC strains. The clinical trial on ICRC vaccine has shown that the ICRC bacilli is immunogenic in Man. The biochemical data on ICRC strain show that they possess DOPA-Oxidase and can express biochemical character of 9/10 similarity index with M. leprae with appropriate substrates in the medium. Thus, the ICRC strains possess both M. leprae and M. avium characters. An hypothesis is proposed to explain these observations--The 'Janus face' of M. leprae--by proposing a relationship between M. leprae and its culture isolates, e.g. ICRC bacilli (1). The M. leprae-culture isolate may by a recombinent of M. leprae with M. avium background (2). The ML-isolate may express the CMI related antigenic determinants corresponding to that of M. leprae in the biopsy (3). The CMI related antigens of whole bacilli in the ML-culture isolate may be inducing type as against only eliciting antigen expressed by M. leprae (4). Recombination may provide immunogenicity as well as 'in vitro' growth potential to the ML-culture isolate (5). Absence or failure to express inducing antigen by M. leprae maybe alternate biological escape mechanism from immune surveillance for survival in vivo, with or without suppressor mechanisms.

Animals↗
PubMedDate not supplied

Effect of hydrocortisone on arginase activity in ICRC mouse mammary tumours in vitro.

Three fold increase of arginase activity was observed in hydrocortisone treated mammary tumour tissue when compared to the untreated tissue in vitro. No change in succinic dehydrogenase activity was observed. It is likely that arginase present in mammary tumour is due to the presence of mammary tumour virus and it is tempting to speculate that the increase in arginase activity by hydrocortisone may be due to sustained viral production in the presence of hydrocortisone.

Animals↗