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Biomedical subjects

R S Misra

Publications and source records attributed to R S Misra.

At least 73 records · Page 4Linked to original sources
PubMed1990

Uptake of purine and pyrimidine nucleosides by macrophage-resident Mycobacterium leprae: 3H-adenosine as an indicator of viability and antimicrobial activity.

Freshly extracted human- and armadillo-derived Mycobacterium leprae maintained within murine macrophages incorporated significant levels (p less than 0.05 to p less than 0.001) of 3H-adenosine and 3H-hypoxanthine by 6 and 9 days of the culture period. The incorporation of 3H-adenosine was twofold or more higher than 3H-thymidine in 10 out of 15 human-derived M. leprae isolates. Macrophage-adapted bacilli incorporated 10-14-fold higher levels of 3H-adenosine compared to the same bacilli maintained in axenic cultures. The incorporation of these two labels was inhibited by dapsone and rifampin, indicating the utility of in vitro radiometric assays for screening antileprosy drugs and drug sensitivity/resistance in patients.

Animals↗
PubMed1989

Hypomelanosis of ito: histochemical and ultrastructural observations.

Skin biopsies were taken from an infant girl with Hypomelanosis of Ito (Incontinentia Pigmenti Achromians) for histopathological, histochemical and electron microscopic studies. Histological observations were similar to those reported previously. Electron microscopy revealed two groups of melanocytes, an effete group and another group with a highly dendritic appearance. The significance of these findings is discussed.

Female↗
PubMed1989

Mycosis fungoides with fatal brain involvement.

The clinical course, therapy and investigations in a man with lichenoid mycosis fungoides which resulted in fatal spread to the brain is described. Immunological studies revealed a significant reduction in T cell numbers. Brain lesions were confirmed by CT Scan and drill biopsy. The literature on the subject is discussed.

Brain Neoplasms↗
PubMed1989

An electron microscopic study of lymphatics in the dermal lesions of human leprosy.

The dermal lymphatic vessels in lepromatous and tuberculoid leprosy lesions were studied by light- and electron-microscopy. In the lepromatous patient, lymphatic vessels were seen in both intra- and peri-granulomatous areas. The lymphatic lining cells contained lipid droplets, lysosomes, and numerous pinocytotic vesicles. Cells bearing bacilli were only occasionally seen. In the tuberculoid cases, lymphatic vessels were seen only along the edges of the granulomas and the lining cells were less prominent. Inflammatory cells, both lymphocytes and histiocytes, were found traversing the walls of lymphatic vessels in both groups of patients. The results of the study confirm the continued and increased functioning of the lymphatic drainage system in dermal leprosy lesions, and indicates that it may be a major route for the clearance of lipids from the lipid-rich bacilliferous lesions in the lepromatous patient. The lymphatic pathway appears to be a minor pathway for the dissemination of Mycobacterium leprae in comparison with the blood vascular system.

Humans↗
PubMed1989

Leprosy in low endemic areas of India: an appraisal and suggested measures for control.

Prevalence of leprosy in the low endemic areas of India is described based on the observations of patients attending an Urban Leprosy Centre in the Union Territory of Delhi from the neighbouring states. The rising incidence in these so-called low to moderate endemic places is closely linked to factors related to urbanisation, movement of people in search of employment, etc., which necessitate fresh surveys in these areas. A significant number of leprosy patients attending the Centre were irregular (37.7%) in therapy and many absconded after the initial visit (35.3%), the reasons for which are discussed. These figures are compared to that from similar low endemic areas and known high endemic parts of the country. Suitable modifications to the control programme in these areas are suggested under the purview of the National Leprosy Eradication Programme.

Adolescent↗
PubMed1988

Neural differentiation of melanocytes in vitiliginous skin.

Biopsies from 74 cases of vitiligo were examined to study the reactions of marginal melanocytes. In 35 cases, the melanocytes at the edge of the patch appeared highly dendritic and large with marked arborization of the dendrites between the surrounding epidermal cells. These cells showed low pigmentation but a high enzyme activity which extended along the dendrites. The enzymes include tyrosinase/dopa oxidase, dopamine oxidase and noradrenaline activity, indicating that these cells have a biphasic melanogenic/adrenergic differentiation. This similarity between the dendritic melanocytes and the amelanotic melanoma cell line HT-18 is of interest.

Cell Differentiation↗
PubMed1987

Secondary tuberculosis of the skin. Clinical features and problems in laboratory diagnosis.

One hundred patients with secondary skin tuberculosis--59 with lupus vulgaris (LV), 27 with scrofuloderma (SD), and 14 with tuberculosis verrucosa cutis (TVC)-were included in this study. The buttocks and lower limbs were seen to be important sites of involvement in LV, besides the occurrence over the face. An active focus of tuberculosis was present in 18, a past history of pulmonary tuberculosis in 8, and intrafamilial tuberculous infections in 21. Histopathology and culture for Mycobacterium tuberculosis were done in all the cases. Guinea pig inoculation was done in 11. The poor results of these investigations have been highlighted and discussed with reference to studies done in the past by other workers. The need for improvement in laboratory techniques is suggested.

Adolescent↗
PubMed1987

Reaction of dendritic melanocytes in vitiligo to the substrates of tyrosine metabolism.

Frozen sections of vitiliginous skin were treated with the substrates involved in melanogenesis and adrenergic activity to study the effect of changing chemical milieu on the biphasic dendritic melanocytes. The substrates used are tyrosine, DOPA, tyrosine + DOPA, dopamine, adrenalin and cupric ions. It was observed that tyrosine when used alone has a weak melanogenic reaction while DOPA and tyrosine + DOPA show a prominent activity. Adrenalin and dopamine inhibit the neural limb and enhance melanogenesis. Cupric ions on the other hand enhance the neural limb and inhibit melanogenesis. These changes are not evident in the non-dendritic melanocytes. Thus the highly dendritic melanocytes are at a lower state of differentiation. These biphasic cells are more sensitive to changes in the chemical milieu.

Copper↗
PubMed1987

Specific skin ulcers in Hodgkin's disease.

A young man with Hodgkin's disease who experienced specific cutaneous ulcers over the scalp during treatment is described. The relation of such ulcers to the disease's progress is discussed.

Adult↗
PubMed1986

Oral cysticercosis.

A 35-year-old Indian male with nodules in the tongue, lower lip and subcutaneous tissues and convulsions of recent onset is presented. Surgical excision of the nodules confirmed the clinical diagnosis of cysticercosis and relieved the lingual discomfort. This is the 26th case of oral cysticercosis being reported.

Adult↗
PubMed1985

Ultrastructure of leprous phlebitis.

An ultrastructural study on vein biopsies from six lepromatous leprosy patients was carried out. The results showed that a) the lumen-lining bacillated cells were endothelial in origin due to the presence of specific Weibel-Palade endothelial cell granules; b) endothelial cells released Mycobacterium leprae into the lumen by exophagocytosis; c) M. leprae were able to grow and multiply in the endothelial and smooth muscle cells; and d) smooth muscle cells did not show any evidence of reaction due to the presence of M. leprae in their cytoplasm.

Adult↗