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Biomedical subjects

G Ramu

Publications and source records attributed to G Ramu.

At least 55 records · Page 3Linked to original sources
PubMed1987

Suppression of delayed hypersensitivity skin reactions to tuberculin by M. leprae antigens in patients with lepromatous and tuberculoid leprosy.

Delayed hypersensitivity skin reactions to tuberculin when injected alone or in mixture with antigens of M. leprae were examined in leprosy patients and in healthy controls. The tuberculin reaction was significantly inhibited in more than one half of both LL and BT patients by the soluble extract of M. leprae (leprosin), the leprosin derived 12 kD protein or leprosin depleted of the 12 kD antigen. However, suppression was not found in healthy controls from a leprosy endemic region. These results suggest that multiple M. leprae-specific antigens have an immunoregulatory function. Since suppression was demonstrable not only in LL (leprosin-anergic), but also in BT (leprosin-responder) patients it is of interest that the 'mixed' skin test can discriminate the immune status of at least certain BT patients from that of the infected but self-healing healthy controls. Corollary lymphocyte cultures failed to show any suppression by leprosing of the lymphoproliferative responses to tuberculin.

Antigens, Bacterial↗
PubMed1987

Comparison of three regimens containing rifampin for treatment of paucibacillary leprosy patients.

Three regimens containing rifampin have been tried in paucibacillary leprosy patients. The patients were selected according to the criteria laid down by the World Health Organization (WHO). In Regimen I, rifampin 600 mg is given once a month for 6 months with dapsone 100 mg daily. Treatment is stopped at the end of 6 months. Regimen II is the same as Regimen I, and is supplemented with an additional 6 months' treatment with dapsone 100 mg daily. Regimen III is the same as Regimen II, except that rifampin is administered daily for the first 7 days. At the end of the scheduled treatment period, 72.2% of the patients in Regimen I, 94.9% of the patients in Regimen II, and 97.1% in Regimen III became inactive. Eighteen out of the 25 active cases at the time Regimen I treatment was stopped had to be restarted on drug therapy since they showed a worsening of their disease, as indicated by an increase in their bacterial index, the appearance of new lesions, renewed activity in old lesions, an increase in the size of old lesions, or development of nerve abscesses. The remaining seven cases regressed without further treatment. All four Regimen II patients and two Regimen III patients who had evidence of activity at the time treatment was stopped did not require any further treatment. On follow-up for 1 1/2 years, three Regimen I patients and none of the Regimen II or Regimen III patients showed relapses. It is thus apparent that rifampin helps to shorten the time duration and to increase the cost effectiveness of treatment of paucibacillary leprosy cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Immunohistological analysis of skin reaction to My1 derived from Mycobacterium leprae.

A study was made on the in situ characteristics of dermal infiltrates in a 24-hr skin reaction using monoclonal antibodies defining T-cell subsets, Ia-like antigens, Langerhans' cells, My1, and indirect immunofluorescence. The skin reaction was induced by the mycobacterial antigen My1 derived from Mycobacterium leprae. In all, 10 biopsies were studied. The infiltrates were composed of lymphocytes and polymorphonuclear leukocytes. The predominant lymphocytes in the infiltrates were activated T lymphocytes expressing OKT11, Leu3a, OKT8, and Ia-like antigens. The ratio of Leu3a+:OKT8+ cells was 1.2 +/- 0.50. Some of the cells in the infiltrates showed the presence of My1, as seen by the staining with MLO6 monoclonal antibody. No difference was observed in the numbers of OKT6+ epidermal Langerhans' cells in the skin of My1 reaction biopsies and those of normal individuals.

Antigens, Bacterial↗
PubMed1985

Reduced complement-mediated immune complex solubilization in leprosy patients.

The ability of sera from leprosy patients to solubilize immune precipitates in vitro through the complement system was studied. The solubilizing capacity of sera from patients who did not have any reactions during 2 years or more after starting chemotherapy was comparable with that of normal laboratory volunteers. On the other hand, sera from borderline tuberculoid and lepromatous leprosy patients in reaction had markedly decreased levels of solubilization. Their total and the alternative pathway haemolytic levels did not show a corresponding decrease. Although the circulating immune complexes and serum C3d of these patients came down after the subsidence of reaction, their solubilization remained consistently low during a 3 month follow-up period.

Antigen-Antibody Complex↗
PubMed1985

Serological survey of leprosy and control subjects by a monoclonal antibody-based immunoassay.

A serological antibody competition test (SACT) using a murine anti-Mycobacterium leprae-specific monoclonal antibody (ML04) has been evaluated in 96 untreated leprosy patients and 128 control subjects. The test is based on the competitive inhibition by antibodies from human test sera of the binding of the specific 125I-ML04 murine monoclonal antibody to M. leprae soluble antigen coated microtiter plates. Along the spectrum of the disease, SACT positivity was observed in 100% of LL-BL, 87.5% of BB, and 46.7% of the TT-BT groups of patients. Moreover, 46.4% of apparently healthy household family contacts of multibacillary leprosy cases were also antibody positive. Sera from 15 contacts of paucibacillary leprosy cases as well as from 85 various nonleprosy subjects (tuberculosis, autoimmune disease, cancer, and healthy) were all found to be negative. These results satisfy the requirements of a leprosy-specific serodiagnostic test. The striking increase of antibody titer in all of the LL/BL patients indicates a potential prognostic utility of this test for the lepromatous shift of the disease. The observed positivity in a fraction of healthy leprosy contacts still requires prospective evaluation of disease incidence in a larger test sample.

Antibodies, Bacterial↗
PubMed1984

Isolation and analysis of circulating immune complexes in leprosy.

Circulating immune complexes (CIC) were isolated by two antigen nonspecific methods from 60 leprosy patients belonging to borderline tuberculoid (BT) and lepromatous (LL) types with and without reactions. CIC were elevated in both BT and LL reactions. CIC from BT in reaction (BTR) were found to consist largely of IgG and C3, whereas, C-reactive protein could be found in CIC from LL reactions (LR). In addition, IgM and rheumatoid factor were demonstrated in the complexes of LR patients who had mainly arthritis. Antimycobacterial antibody was seen in the complexes of two-thirds of LR patients who had predominantly skin manifestations as part of their reaction. The relevance of these findings to the clinical manifestations of different types of reactions is discussed.

Animals↗
PubMed1983

A serological test for leprosy based on competitive inhibition of monoclonal antibody binding to the MY2a determinant of Mycobacterium leprae.

A novel serological assay for leprosy has been devised on the basis of serum inhibition of binding of 125I-labelled ML04 monoclonal antibody to Mycobacterium leprae sonicate-coated microtitre plates. Antibodies were detected in 93% of lepromatous leprosy patients, whereas controls from the endemic area, including leprosy contacts and patients with tuberculosis, were serologically negative. The specificity and efficacy of the test may offer an advantage over previously used techniques.

Antibodies, Bacterial↗
PubMed1983

Evaluation of drug regimen in lepromatous leprosy--II.

A 2 year follow-up study of 4 drug regimen in 45 cases is reported; whereas the combination of Rifampicin and Dapsone had been found to effect clearance of bacteraemia within a week and effect negativity of nasal smears in a shorter period of time, at 2 years the clinical and bacteriological results in the DDS, DDS + Rifampicin, DDS + Thiacetazone + INH, and DDS + Clofazimine regimen were similar. However, on inoculating bacilli obtained from the dartos muscle into the foot-pads of mice, multiplication was found in 1 out of 11 cases on Rifampicin and DDS, whereas 2 out of 9 cases on DDS + Thiacetazone + INH; 2 out of 10 cases on DDS + Clofazimine and 4 out of 8 cases on DDS alone showed multiplication. Therefore at the end of 2 years there was no significant difference in the results of treatment with any of the drug combinations used in the trial. However, the drug combinations have been found to be better than monotherapy with dapsone alone.

Adult↗
PubMed1983

Hepatitis-B virus infection in patients with leprosy--a brief communication.

The prevalence rate of hepatitis-B surface antigen (HBsAg) were determined in 413 patients of different types of leprosy and 133 healthy controls from the same population, in a study undertaken over a period of more than 3 years. The average frequency of australia antigen (HBsAg) was 7.7% in leprosy cases as compared to 6.0% in their healthy counterparts. Across the spectrum 7.2% of lepromatous patients (LL); 8.5% of borderline lepromatous (BL); 9.1% of borderline borderline (BB); 8.6% of borderline tuberculoid (BT) and 8.8% of tuberculoid (TT) cases were positive for HBsAg. Though the prevalence of australia antigen was slightly higher in borderline tuberculoid, borderline borderline and tuberculoid cases, it is not statistically significant. No association between carriership of HBsAg and lepromatous leprosy could be found in the present study.

Adult↗
PubMed1983

Further modification on the haemolysis method in determining bacteraemia in leprosy patients.

Bacteraemia was assessed and compared in the venous blood samples of leprosy patients by employing the existing and the modified haemolysis method respectively. The modified method was more sensitive in determining bacteraemia in these patients as evident from the finding of more number of positive cases detected by this method. A significantly higher yield of bacterial number was detected by employing the present method when compared to that obtained by earlier method.

Adolescent↗
PubMed1983

Short course treatment of tuberculoid cases--a feasibility study.

With an aim to reduce the length of treatment of leprosy, as a first step an investigation has been undertaken to evaluate the efficacy of maintenance therapy in non-lepromatous cases. Relapse rates in a group of 47 cases, in whom treatment had been given only til the point of inactivity (the trial group) have been compared with a similar group of 27 cases who received additional 18 months maintenance therapy (the control group). No difference in relapse rates has been found (2.13 per 1000 patient months in trial group as against 2.58 per 1000 patient months in the control group). This suggests that additional 18 months maintenance therapy, as is currently recommended, does not offer any additional advantage in reducing the relapses.

Adult↗
PubMed1983

Involvement of subcutaneous veins in lepromatous leprosy.

Venous involvement in 31 patients with lepromatous leprosy has been studied in biopsies from clinically involved and clinically normal subcutaneous veins from the forearm. Twenty-nine of these showed histological evidence of leprous phlebitis. The earliest lesion was intimal cell hyperplasia with the presence of acid-fast bacilli in small groups in the intimal cells. This gradually progressed to total occlusion of the vein by lepromatous exudate. The results indicate much greater involvement of veins and possibly other components of the vascular system in patients with lepromatous leprosy than is generally accepted. The importance of such involvement in the pathogenesis of leprosy is also discussed.

Adolescent↗
PubMed1983

Sequential histological study of lepromin reaction.

Skin testing with Dharmendra antigen was performed on 55 patients with TT, BT, BL, and LL types of leprosy and the reaction measured at different intervals from 24 hr to 28 days. At various time intervals, a biopsy specimen was taken from the reaction site. In TT and BT cases, the erythema was maximum at 48 hr; while the induration was maximum at 21 days. The sequence of the histological changes was built up on the observations made from different cases at varying intervals. The quantum of cellular exudate was high in TT and BT cases as compared to BL and LL cases. The cellular distribution showed loose scattering of cells in the LL and BL types and attempts to form tight clusters in the TT and BT cases. Neutrophils were predominant during the first 48 hr, particularly in the LL, BL, and BT types. By 72 hr the cells were mainly lymphocytic. A tendency for the lymphocytes to cluster around nerve twigs was seen in the TT and BT cases. In the early reaction the quantum of exudate correlated both with erythema and induration; while in the late reaction, it correlated with induration only. The intensity of the early lepromin reaction was more in BT than in TT leprosy, while the induration in the late reaction was more in TT than in BT types. The significance of these findings is discussed.

Adult↗