Biomedical subjects
Publications and source records attributed to U Sengupta.
Leprosy patients were skin tested for induction of skin delayed type hypersensitivity (DTH) with various preparations of Dharmendra Antigen (DA) (sonicated antigen, DNA + RNA and DNA). Extracted nucleic acids produced smaller reactions (including some negative ones) as compared to sonicated whole antigen (which included proteins). BCG fractions, prepared similarly, produced non specific skin reactions.
Assessment of bacteraemia has been made at weekly intervals in 36 lepromatous leprosy patients who were put on different antileprosy drug under four regimens, viz., DDS alone, DDS in combination with rifampicin (DDS + RIF), clofazimine (DDS + CLF) and thiacetazone (DDS + TCT). In general, with the continuation of treatment the bacillary load in the blood decreased considerably while bacteriological index (BI) of the skin remained constant during the study. No significant difference was noted in M. leprae clearance from blood between the groups treated with DDS alone and groups treated in combination with CLF and TCT. However, DDS + RIF treatment was most efficient in clearing acid-fast bacilli (AFB) from blood as compared to those noted with other drug regimens.
A stimulatory effect of soluble starch on the growth of M. lepraemurium in vitro cell-free culture system has been noted. In this medium bacteria elongated gradually without manifesting any significant peak in elongation as has been noted in NC-5 medium. The maximum average elongation of bacteria was 2.84 mu on the 24th day in NCS-5 medium. In contrast, in NC-5 bacteria elongated maximum on the 6th day (2.32 mu). All the stages of bacterial cell division were noted. Hypothesis has been suggested for continuous multiplication of M. lepraemurium in NCS-5 medium.
A relationship between the early phase of growth of M. lepraemurium in vitro in NC-5/ND-5 media and elongation of bacteria has been noted. The doubling time in NC-5 is 3.06 days whereas it is 1.97 days in ND-5 medium. In ND-5 medium, M. lepraemurium elongates earlier to that in NC-5. Furthermore, in ND-5 the peaks in elongation of bacteria are more frequently noted than in NC-5 medium. Morphological observations have shown all stages of bacterial cell-division. At later stages of cultivation (21st and 24th day) M. lepraemurium often shows terminal swelling in ND-5 medium which also revealed stages of cell-division.
In order to pinpoint the active portion of the skin antigens including Dharmendra and other lepromins, a study was carried out by subjecting the antigens to electrophoretic and immunoelectrophoretic analysis. These analyses identified two components, anionic and cationic, in lepromin sonicates. The anionic component was stainable with a protein strain, whereas cationic component formed precipitin arcs on immunoelectrophoresis with sera from lepromatous leprosy patients. BCG sonicate could also be resolved into two similar components. The cationic component of BCG apparently a glycoprotein, cross reacted with cationic component of lepromin and also showed a reaction of identity in gel diffusion. The specificity of anionic (proteinaceous) component of lepromin remains to be established.
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101 patients belonging to different types of leprosy were investigated for PHA-induced lymphocyte transformation in peripheral blood. There was a significant depression (P < 0.05) in blastogenesis in borderline (BB), borderline lepromatous (BL) and lepromatous (LL) patients. On the other hand, tuberculoid (TT) and borderline tuberculoid (BT) patients did not show any alteration in PHA-induced blastogenesis (P > 0.05) when compared to normal. The significance of these findings have been discussed.
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A study to find out the in vitro effect of diamino diphenyl sulphone (DDS) on phytohaemagglutinin (PHA)-induced lymphocyte transformation was carried out in three phases using a wide range of DDS concentrations. Lymphocytes from healthy volunteers were investigated. Volunteers were divided into three groups to conduct the study in three phases. In each phase in addition to 0.02 ml of PHA, 4 different concentrations of DDS were added per 10(6) lymphocytes in tissue culture system. A statistically significant depression (P less than 0.05) in the per cent of blast cell formation induced by PHA was observed in the cultures with all the concentrations of DDS except with the lowest concentration (0.01 microgram) of DDS. While the depression observed in the first and the third phase was found to be dose dependent, no significant correlation was noted between the DDS concentration and depression in PHA induced blastogenesis in the second phase. The significance of these observations are discussed.
IgG levels were significantly high in sera of all types of leprosy. House-hold contacts of lepromatous leprosy (LL) cases also showed significantly higher values for IgG when compared to that of control. Except polar tuberculoid (TT) cases and house-hold contacts other types of leprosy revealed a significant rise in IgA levels in their sera. IgM was only raised in borderline tuberculoid (BT) cases. C-reactive protein (CRP) was present in the sera of all types of leprosy. Highest positivity (97%) was shown by sera from erythema nodosum leprosum (ENL) cases. Rose-Waaler antibody (RA) was noted in BT, borderline leprosy (BL), LL and ENL cases. Significance of these findings is discussed.
Dharmendra antigen with different bacterial counts (16, 12.5, 10, 7.5, 5 and 2.5 million/ml) have been utilized for determination of skin delayed hypersensitivity in leprosy patients. It has been noted that antigen with 10 million acid fast bacilli (AFB)/ml mounts a standard early (24 hrs) as well as late (3 weeks) reaction in patients. Lepromatous patients do not show any skin reaction with this dilution. Thus, a standard Dharmendra antigen has been prepared using a considerably smaller number of organisms as compared to the International standards for Mitsuda antigen.
Four fractions each from Dharmendra and Mitsuda antigen have been obtained by step-wise centrifugation and sonication of the antigen. These fractions have been assessed for their capacity of inducing skin delayed hypersensitivity response. While, it has been noted that all fractions of both types of antigens can induce a good early reaction, the late skin reaction is only mounted by intact bacilli of both types of antigen. When compared at a constant bacillary concentration, Dharmendra antigen has produced better early skin reaction than Mitsuda antigen, whereas the intensity of late skin reaction is almost equal with both the antigens. The hypothesis has been put forward that the early, as well as the late reaction are produced by the same antigen and this antigen is located in the protoplasm of M. leprae.
Depression in PHA-induced lymphocyte transformation in peripheral blood has been observed in 15 healthy volunteers after administration of DDS (100 mg/day) for seven days. In vitro culture of lymphocytes obtained from these volunteers in DDS-free normal AB serum has not altered the blast cell numbers. Lymphocytes of these volunteers have been found to contain a significant amount of DDS, ranging from 0.42 to 3.2 micrograms per 10.6 lymphocytes.
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Thirty five patients of leprosy have been screened for bacteraemia by haemolysis (HL), leucocyte adherence (LA) and buffy coat (BC) methods and the results have been compared. The HL method has yielded not only higher number of acid-fast bacilli (AFB) but also has detected more frequently AFB in blood of leprosy patients as compared to other methods. Further, it has been established that the skin over the cubital fossa does not play any significant role in contaminating blood samples while sampling blood by venepuncture.
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