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Biomedical subjects

C K Job

Publications and source records attributed to C K Job.

At least 163 records · Page 9Linked to original sources
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The Kveim test in leprosy.

The response to lepromin and Kveim antigens was compared and studied in 15 leprosy patients who were tuberculin negative. Of the 11 lepromin positive tuberculoid patients, 4 were Kveim positive, 1 was equivocal, and the rest were negative. Of the four lepromin negative lepromatous patients, one gave a positive Kveim test while the other three were negative. It has been shown that false-positive Kveim reactions are found in a higher percentage of South Indian leprosy patients than in those of other backgrounds, such as Japanese and Malaysian Chinese patients. It is also suggested that no definite relationship exists between the reaction of leprosy patients to lepromin and Kveim antigens. We further suggest that the anergy exhibited by lepromatous patients to the antigen of M. leprae is specific, as evidenced by the positive Kveim response in one lepromatous patient.

China↗
PubMedDate not supplied

Drug resistant-Mycobacterium leprae--results of mouse footpad studies from a laboratory in south India.

Out of 265 biopsies of leprosy patients received at the Experimental Pathology Laboratory of Schieffelin Leprosy Research and Training Centre from 1987 to 1997 for evaluating resistant strains of M. leprae, using the mouse footpad technique, 49 showed resistant strains of M leprae to varying concentrations of dapsone, rifampicin and clofazimine. 23 (47%) of these were from a control area. With 369 skin-smear positive multibacillary (MB) patients as the risk group (denominator), 23 (6.23%) were resistant to one or more drugs. 18 (4.88%) had dapsone resistance, 5 (1.36%) were resistant to rifampicin and 9 (2.44%) had resistance to low concentrations of clofazimine (0.0001%). Out of the 23 biopsies with drug resistance from the control area, primary dapsone resistance was seen in 7 (30%) biopsies and secondary dapsone resistance in 11 (48%). Primary rifampicin resistance was seen in 4 (17.4%) patients, secondary rifampicin resistance in 1 (4.35%) and primary clofazimine resistance in 7 (30%). 3 (13%) of the strains showed secondary clofazimine resistance. One biopsy had resistant strains to all the three drugs. In a control area where properly supervised effective multidrug therapy (MDT) was regularly administered over the years, the emergence of drug resistance is negligible. It may not be the case if the content, duration and regularity of the drug regimen were not satisfactory. Aware of the possible shortcomings in mass administration of MDT, it is emphasized that mouse footpad studies on drug resistance should be made available at least in endemic areas where the incidence of the disease has not changed despite good MDT coverage in order to monitor the emergence of drug resistance. Research into molecular biological identification of drug resistant-M.leprae should be intensified. These steps would help to institute timely measures to check the spread of any drug-resistant organisms in the community.

Animals↗
PubMedDate not supplied

Are viable Mycobacterium leprae present in lepromatous patients after completion of 12 months' and 24 months' multi-drug therapy?

A study was carried out to determine whether or not viable bacilli persist in MB patients treated with 12-month and 24-month multidrug therapy (MDT). In the first group, 60 untreated lepromatous patients who had an initial average bacterial index (BI) of 3+ or more were enrolled. At the completion of 12 months of MDT, skin biopsies were obtained and M. leprae concentrate was inoculated into the footpads of five thymectomized and irradiated (T900r) mice. Rees technique was used for the mouse footpad (MFP) experiment. Harvesting was done it the 6th, 9th and 12th months. Out of the 60 biopsies inoculated into mouse footpads to check the viability of bacilli, 2 skin biopsies (3.3%) showed significant growth and 10 (16%) showed equivocal growth. 27 patients also had nerve biopsies tested for growth in MFP studies. None of the inoculated nerve biopsies showed significant multiplication in the MFP experiments. However, 4 biopsies (14%) showed equivocal growth. In the second group, 20 patients had skin biopsies and 10 had nerve biopsies done at the end of 24 doses of MDT in order to test the viability of bacilli; none of the skin or nerve biopsies from these patients showed any growth. This study showed that M. leprae present in the tissues after 24 doses of MDT are not viable and the drug schedule of 24 doses is adequate to treat leprosy patients, irrespective of their BI. However, a small (3.3%) percentage of the patients with a high BI harbour viable bacteria in the skin after 12 doses of treatment. Since a large majority of the patients (38 patients) who had a high initial BI responded well to the treatment, it is important to find out the reason for the lack of response in two patients. One of the reasons may be the presence of drug-resistant strains. It is important to follow up on these patients for a longer duration to ascertain whether or not they would relapse.

Adult↗
PubMedDate not supplied

The pathogenesis of leprosy in the nine-banded armadillo and the significance of IgM antibodies to PGL-1.

Twenty-seven nine-banded armadillos captured from the wild and tested free of wild M. leprae infection were distributed into four groups. They were injected at the right hind footpad with saline suspensions of M. Leprae at doses of 10(3), 10(4), 10(5) and 10(6). PGL-1 antibody levels were estimated using an ELISA test, twice during six months before the infection and every two months after the infection. One animal from each group was sacrificed at 6, 12, 18, 24, and 30-month intervals and another eight at unspecified intervals. A thorough autopsy and histopathological examination were conducted on all of them. Of the 27 animals, 18 developed the infection. In 10, there were granulomas at the site of inoculation and in 17 the regional lymph nodes were infected. The disease spread extensively to other lymph nodes and to the liver and spleen and then to the other organs. Peripheral nerves were invaded by M. leprae in only five animals. PGL-1 antibody levels registered a positive reading in only six of the 18 animals with the infection. In armadillo leprosy, the lesions did not persist at the site of entry in all animals M. leprae multiplied in the macrophages at the site of inoculation and the reticuloendothelial cells of the lymph nodes before they spread to other organs. There was evidence of invasion of endothelial cells of capillaries and possible bacteraemia even at an early phase of the infection. Peripheral nerves were not the preferred sites of entry or multiplication of M. leprae. Progressive increase in PGL-1 antibodies was recorded in five lepromatous armadillos with disseminated infection and high bacterial load. However, PGL-1 antibodies response was not sensitive enough to detect early disease.

Animals↗
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Light and electron microscopic appearances of peripheral nerves from two lepromatous leprosy patients after 12 months of multidrug therapy and their significance.

Biopsies from radial cutaneous nerves of a lepromatous patient and one borderline lepromatous patient treated with 12 doses of multidrug regimen were studied using light and electronmicroscopes. Histopathologically both showed typical lepromatous neuritis. Electronmicroscopic examination showed demyelination, atrophy and degeneration of myelinated axons and nonmyelinated axons and a marked increase in collagen fibrils. Perineurial cells, Schwann cells and endoneurial macrophages contained numerous persisting M. leprae. Almost all the organisms in macrophages were fragmented and could be considered non-viable. A few M. leprae found in Schwann cells showed structure of viable bacilli. It is possible a few dead or dormant organisms may persist for many years in Schwann cells or in fibrous tissue without producing any ill effects, and may cause relapse only in rare instances. Since 12 months of MDT resulted in the clearance of M. leprae in course of time and the reported relapse rates after years were insignificant, implementation of MDT for a year for all MB patients is justified provided surveillance of these patients is ensured. Administration of uniform MDT for 6 months is worth a trial.

Adult↗
PubMedDate not supplied

An attempt to produce experimental tuberculoid leprosy in the nine-banded armadillo.

In an attempt to produce experimental tuberculoid leprosy, three nine-banded armadillos, two with borderline tuberculoid lepromin reaction, and one with tuberculoid lepromin reaction, were chosen. They were injected subcutaneously in a four square centimetre area in the abdominal skin with saline suspension of 6.5 x 10(7) M. leprae. Induration of skin at the injected site appeared in 24 hours and persisted for 6 months in one and for 18 months in the other two animals. Histopathological examination of the infected site at 6 weeks, 18 and 20 months showed progressively decreasing granulomatous inflammation; but the cutaneous nerves were uninvolved. Autopsy examination of the three animals failed to show disseminated disease. Since there was no evidence of nerve involvement, experimental transmission of tuberculoid leprosy to armadillos could not be established in this study.

Animals↗
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Nine-banded armadillo (Dasypus novemcinctus) as an animal model for leprosy.

Dr. Dharmendra was one of the most distinguished leprologists of our time. He loved India so much that he offered his entire life to fight leprosy, a major health problem in India. He realized the great need in this much neglected field of medicine and willingly gave his utmost, whatever be the cost. He served in the field of leprosy with great distinction and he earned the respect of his fellow workers from all over the world. He made outstanding contributions to the study of leprosy, the identification and isolation of the active principle in the lepromin reagent, the use of lepromin test for identifying persons susceptible to leprosy, the use of an antileprosy drug as a means of chemoprophylaxis, the nurturing of the Indian Journal of Leprosy and developing it as one of the foremost leprosy journals, are a few of his major contributions. He received many well deserved national and international honours and awards. I first met Dr. Dharmendra in 1956 and feel privileged to have known him and to be associated with him all these years. I am honored to be asked to contribute this paper for a publication meant to pay tribute to his memory.

Animals↗
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Phagocytosis of Mycobacterium leprae by cardiac muscle cells--a preliminary report.

Fetal cardiac muscle cells were shown to ingest M. leprae easily within 20 minutes of exposure in vitro. This phagocytosis is considered nonspecific and facilitated by the lipid coat of the mycobacteria. The presence of M. leprae free in the cytoplasm of the muscle cells did not seriously affect the morphology or rhythmic contractions of the cells. The significance of the presence of M. leprae in somatic cells needs further study.

Animals↗
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Early infection with M. leprae and antibodies to phenolic glycolipid-I in the nine-banded armadillo.

Nine-banded armadillos were intravenously infected with 10(9) M. leprae. IgM antibodies to PGL-I were evaluated three times during the six months before and every two months after the infection. A thorough autopsy examination was done on animals that died or were sacrificed at intervals of 3, 4, 6, 12, 15 and 18 months after the infection. Three animals which had acquired the infection in the wild and one experimentally infected animal showed significant increases in antibody levels corresponding to their high bacterial load. In the other five experimentally infected animals, M. leprae infection was established in the cells of the reticulo endothelial system (RES) long before the IgM antibody levels to PGL-I became positive. It is possible that in human leprosy also M. leprae may enter and multiply in the RES initiating antibody production during the incubation period before clinical disease with neuritis becomes manifest.

Animals↗
PubMedDate not supplied

Our experiences with breeding of nine-banded armadillos (Dasypus novemcinctus) in captivity.

The nine-banded armadillo is considered the best animal model in the study of leprosy. Armadillos have never been successfully bred in the laboratory and therefore animals required for the experiments are captured from the wild and are likely to carry many diseases including leprosy. An attempt was made to breed them in captivity. Our attempt to house them in various combinations in their natural environment in the farmlands of Louisiana was successful. Although a significant increase in conception and delivery was recorded, consistent breeding of the animals was not obtained.

Animal Husbandry↗