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Biomedical subjects

A Basten

Publications and source records attributed to A Basten.

193 records · Page 11Linked to original sources
PubMed1970

Mechanism of eosinophilia. I. Factors affecting the eosinophil response of rats to Trichinella spiralis.

The phenomenon of eosinophilia was studied in rats using inoculation with Trichinella larvae as the experimental stimulus. Comparisons were made between the eosinophil response accompanying active infestation via the gastrointestinal tract and that resulting from parenteral inoculation of larvae or their products. A vigorous eosinophilia could be provoked by a single intravenous injection of intact parasites. In this circumstance the larvae lodged in the lungs causing an acute inflammatory reaction which led to their disintegration within 24 hr. Intraaortic injection also produced a significant response, whereas inoculation of the same number of parasites by the intramuscular, intraperitoneal, or subcutaneous routes did not cause eosinophilia. Eosinophilia likewise failed to develop if parasites were homogenized before intravenous injection, so that they were not arrested in the lungs. Antibody levels, as measured by a hemagglutination technique, using whole larval extract as antigen, did not correlate closely with the eosinophil response. The findings are interpreted as suggesting that increased eosinophil production is induced under some circumstances as a consequence of interaction between intact parasites and certain host cells in blood and tissue. No evidence was found for the existence of a specific constituent of the parasite capable of stimulating eosinophil production. Attention is directed to features of eosinophilia which fit with the concept that this phenomenon belongs in the category of immunologic reactions.

Animals↗
PubMed1970

Mechanism of eosinophilia. II. Role of the lymphocyte.

A possible role for the lymphocyte in the mechanism of eosinopoiesis has been examined. Procedures known to deplete or inactivate the pool of recirculating lymphocytes such as neonatal thymectomy, administration of antilymphocyte serum, and prolonged thoracic duct drainage, either singly or in combination, resulted in a highly significant reduction in the eosinophil response to trichinosis. Irradiated animals exposed to parasitic challenge did not develop eosinophilia unless reconstituted with lymphocytes as well as bone marrow cells. When "memory" cells were used instead of normal lymphocytes, a "secondary" type of eosinophil response was observed. Transfer of a primary eosinophilia was achieved adoptively with a population of living large lymphocytes from thoracic duct lymph and peripheral blood, but not with blood plasma or cell-free lymph. The potency of the active lymphocytes was not impaired by enclosing them in cell-tight diffusion chambers, indicating that they exerted an effect on bone marrow by agency of a diffusible factor. The demonstration of a role for lymphocytes in induction of the eosinophil response to this kind of stimulus supports the conclusion that eosinophilia belongs in the category of immunologic phenomena.

Animals↗
PubMedDate not supplied

Cross-reactivity of Mycobacterium leprae and M. tuberculosis and the implications for assessment of in vitro T cell function in leprosy patients.

The cross-reactivity in vitro between Mycobacterium leprae and M. tuberculosis was studied in 41 Aboriginal Australians with leprosy, 78 uninfected contacts of leprosy patients and 38 control individuals. A vigorous T cell response to epitopes cross-reactive between these two mycobacteria was found for healthy uninfected contacts or non-contacts (controls) of leprosy patients, but not for the patients themselves. The data suggest that a vaccine based on antigen shared between M. leprae and other mycobacteria is unlikely to be useful in preventing leprosy. Further studies of responses in vitro to purified T cell-reactive antigens would be useful in designing newer vaccines for more widespread field studies of leprosy prevention.

Cell Migration Inhibition↗
PubMedDate not supplied

Subclinical infection with Mycobacterium leprae--a problem for leprosy control strategies.

Tests for the serodiagnosis of leprosy, including those based on phenolic glycolipid-I (PGL-I), have shown poor specificity for leprosy in studies of endemic communities, despite initially promising results in studies of selected patients. During a 5 years follow-up study of a hyperendemic community in Papua New Guinea, a marked reduction in numbers of seropositive children and an increase in age of those seropositive followed introduction of multi-drug therapy. This was accompanied by a reduced case detection rate and a shift to paucibacillary disease in new cases, consistent with a reduction in transmission. Only a minority of persistently seropositive persons developed leprosy. These observations suggest that subclinical infection with Mycobacterium leprae is common in endemic communities and that PGL-I seropositivity is a marker of subclinical infection, with poor specificity for overt disease. Detection of subclinical infection may confound control strategies which use screening tests to identify asymptomatic highly infectious cases for earlier therapy.

Adolescent↗
PubMedDate not supplied

Alpha-interferon (Wellferon) as an adjunct to standard surgical therapy in the management of recurrent respiratory papillomatosis.

Ten patients received lymphoblastoid alpha-interferon (Wellferon) in a crossover study so that Wellferon and standard microsurgical laryngeal laser therapy could be compared to laser therapy alone. Wellferon was administered initially at an intravenous high dose of 15 megaunits/m2 for 5 days followed by a daily dose of 2 megaunits/m2 subcutaneously for 6 months. Dosage was adjusted according to predefined toxicity. One patient was withdrawn from the study. Of the others, all but one received over 75% of the planned total dose. At follow-up of the nine assessable patients, complete remission was achieved in two of them, partial remission in four, and no response in the remainder. The two complete remissions were sustained for 2 years, but the four partial remissions were not sustained. Thus, a role for alpha-interferon in the kind of regimen used here remains to be established.

Combined Modality Therapy↗