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Biomedical subjects

T Y Berhan

Publications and source records attributed to T Y Berhan.

5 recordsLinked to original sources
PubMed1995

In vivo evaluation of immune responses in leishmaniasis: the use of cross-species leishmanin preparations for skin testing.

Skin test reactivity to two commercial preparations of Leishmania major leishmanin was evaluated in leishmaniasis patents from Ethiopia (L. aethiopica) and Nicaragua (probably L. braziliensis complex). The purpose of using different preparations of L. major was to evaluate whether L. major skin test antigens could generally be used to detect leishmaniasis due to L. aethiopica and L. braziliensis. One preparation was superior in identifying the majority (83-90%) of confirmed cases of local cutaneous leishmaniasis (LCL) from Ethiopia. In vitro responses to promastigotes of Leishmania spp. correlated well with leishmanin positivity to this preparation. The skin test antigen, which performed less well (showing a positive result in only 50% of the LCL patients), showed promise when used to test active and cured cases of leishmaniasis in Nicaragua (positive result in 92% of the active and cured patents). Cross-reacting Leishmania spp. may be considered for use in the preparation of standardized leishmanin antigen; however, differences in the commercial preparation or the diluent in which the parasites are prepared may affect antigenicity and thus its efficacy in detecting different forms of leishmaniasis in different geographic areas.

Adolescent↗
PubMed1993

In leprosy the presence of mycobacteria in the nerve is an essential factor in the cycle and spectrum of Mycobacterium leprae infection.

A total of 220 untreated leprosy patients who underwent parallel skin and nerve biopsies are included in this study, which is intended to evaluate the extent of previously reported differences in bacillary load between skin and nerve lesions in leprosy and to describe the response of peripheral blood lymphocytes to Mycobacterium leprae antigens in such patients. In 161 patients out of the 220, the skin and nerve biopsies were diagnostic for leprosy. When patients were grouped according their skin and nerve lesions, the 3 groups observed were (1) paucibacillary skin and nerve lesions; (2) multibacillary skin and nerve lesions, and (3) paucibacillary skin and multibacillary nerve lesions. There was no observation of a group of patients with multibacillary skin and paucibacillary nerve lesions. In all patients with multibacillary nerve lesions, regardless of the type of skin lesions, a low response of peripheral blood lymphocytes to M. leprae was consistently noted. These results suggest that the bacillary load in the nerve is certainly one of the factors determining the immunological spectrum observed in leprosy.

Humans↗
PubMed1992

Thalidomide's effectiveness in erythema nodosum leprosum is associated with a decrease in CD4+ cells in the peripheral blood.

Thalidomide is well documented as being an effective drug in the treatment of erythema nodosum leprosum (ENL). The mechanism of action of thalidomide in ENL as well as the pathogenesis of ENL are yet to be fully determined. Lepromatous leprosy patients experiencing ENL have been reported to have an increase in the ratio of CD4+ to CD8+ cells in their blood and ENL skin lesions. Thalidomide has been shown to cause a decrease in the ratio of CD4+ to CD8+ lymphocytes in the blood of healthy males. This decrease was due to a significant reduction in the numbers of Cd4+ lymphocytes and an apparent increase in the numbers of CD8+ lymphocytes. In this study, thalidomide's effectiveness in halting chronic ENL and arresting a relapse into ENL was consistently associated with a decrease in the numbers of CD4+ lymphocytes in the blood of 2 male lepromatous leprosy patients.

Adult↗