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Biomedical subjects

S L Yan

Publications and source records attributed to S L Yan.

8 recordsLinked to original sources
PubMed1994

Expression and function of multiple regulators of complement activation in autoimmune thyroid disease.

Membrane attack complexes of complement occur around thyroid follicles in Graves' disease and Hashimoto's thyroiditis. The lytic potential of such complexes is controlled by membrane-bound and fluid phase regulators and we have investigated the role of these in autoimmune thyroid disease. By immunohistochemical staining, clusterin and S-protein were found in all nine thyroid specimens from patients with Graves' disease and S-protein was found in one of two Hashimoto glands. CD46, CD55 and CD59 were found on thyroid cells in all specimens. CD46 and CD55 expression occurred on thyroid cells cultured in vitro and was increased significantly by culture with interleukin-1 (IL-1) and interferon-gamma (IFN-gamma), which are known to be released by the lymphocytic infiltrate in these conditions. Blocking CD55 had a weak and inconsistent effect on complement-mediated thyroid cell killing in vitro but, in four of five experiments, blocking CD46 enhanced killing. However, the effect of blocking CD59 was greater in all cases than blocking CD46 or CD55. Expression of these fluid phase and membrane-bound proteins may be important in determining the severity of thyroid damage produced by complement fixation in Graves' disease and Hashimoto's thyroiditis.

Antigens, CD↗
PubMed1992

Stimulation of cutaneous T-cell lymphoma cells with superantigenic staphylococcal toxins.

Stimulation of T cells by superantigenic bacterial toxins is selective for cells bearing particular B chain variable (VB) gene segments of T-cell receptor (TCR). In humans, staphylococcal exfoliating toxin (ExT) and toxic shock syndrome toxin-1 (TSST-1) are known to stimulate VB 2-bearing T cells and staphylococcal enterotoxin B (SEB) does not activate VB 2-bearing T cells. We examined the proliferative response of cutaneous T-cell lymphoma (CTCL) cells to ExT, TSST-1, and SEB. Leukemic VB 2.1-bearing CTCL cells were reactive to ExT and TSST-1, but not SEB. In addition, two leukemia CTCL-VB 2- cell samples (one of which was VB 8) showed no substantial response to ExT. Thus, it was shown that Sezary cells proliferate in response to bacterial superantigens in a manner that is restricted by their VB usage. The addition of interleukin-1 (IL-1) in combination with ExT enhanced the stimulative response of VB 2.1-bearing CTCL cells that were pre-cultured with ExT for 7 d, suggesting that IL-1 can be a co-factor for the stimulation. The present study indicates that the superantigen reaction occurs with CTCL cells and implies a possible involvement of bacterial toxins in the pathogenesis of CTCL.

Antigens, Bacterial↗
PubMed1989

Biological activity in the repopulating rat spermatocyte after the withdrawal of gossypol treatment: I. The activity for DNA synthesis.

Mature male rats were treated with gossypol for various lengths of time after which the treatment was stopped to allow the arrested spermatogonia to revive. Fifteen days after withdrawal of the drug treatment, the arrested spermatogonia entered into the meiotic division and then reached the pachytene stage. The meiotic cells derived from the arrested spermatogonia were the first generation of the differentiated germ cells after long-term gossypol treatment. Centrifugal elutriation technique was used to isolate the repopulating pachytene spermatocytes (RPS) or the control pachytene spermatocytes (CPS) from the rat testis with or without receiving gossypol pretreatment. In vitro culture condition for RPS and CPS was established for the synthesis of DNA by the measurement of 3H-thymidine incorporation. The activity for DNA synthesis in RPS was studied and compared to that of the CPS. It was concluded that after gossypol treatment for various times, the incorporation of 3H-thymidine into the cellular thymidine pool of RPS was not affected. However, the activity for DNA synthesis in RPS was significantly lower than that in the CPS. The synthetic activity for DNA was reduced by 14%, 26%, 42%, 40%, and 40% in the RPS for the gossypol pretreatment of 3, 4, 6, 7, and 8 weeks, respectively.

Animals↗
PubMed1977

External structures of all larval instars of five common Culex species in Taiwan.

The external structures of all larval instars of 5 different species of Culex were studied for the first time in Taiwan. Pictorial keys are provided for use to distinguish each species at any instar; one key is to larval instars of 5 common Culex species in Taiwan and the second, key to species of 5 common Culex species in Taiwan.

Animals↗
PubMed1976

Malic dehydrogenase patterns in different strains of Schistosoma japonicum and subspecies of Oncomelania hupensis.

Malic dehydrogenase (MDH) of the Formosan Philippine and Indonesian Strains of Schistosoma japonicum and 3 subspecies of snails, Oncomelania hupensis formosana, O. h. quadrasi, and O. h. lindoensis were identified by disc electrophoresis with 10.5% acrylamide gel columns using tris-malic buffer. Male worm extracts of S. japonicum demonstrated 3, 2, and 2 clear MDH patterns and female worm extracts showed patterns of 2, 1 and 1 for the Formosan, Philippine and Indonesian strains of the parasite, respectively. MDH patterns were the same for all 3 subspecies of snails; one major and one minor band being found in all.

Electrophoresis, Polyacrylamide Gel↗