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Biomedical subjects

Y B Tan

Publications and source records attributed to Y B Tan.

13 recordsLinked to original sources
PubMed1994

Effects of parathyroid hormone and estradiol on proliferation and function of human osteoblasts from fetal long bone. An in vitro study.

The effect of parathyroid hormone (PTH) (0.01 nM-10 nM) and 17 beta-estradiol (E2, 1 nmol-10 nM) alone or in combination on 3H-thymidine incorporation, alkaline phosphatase and adenylate cyclase activities were investigated in human fetal osteoblasts using serum-free monolayer primary cultures. The results showed that PTH inhibited cell proliferation while E2 promoted it. On alkaline phosphatase activity, PTH showed a complex results while E2 were slightly inhibitory. PHT-E2 combination suggested that E2 could alter the effect of PTH alone, also potentiated the anabolic and antagonize the catabolic effects of PTH on bone formation.

Adenylyl Cyclases↗
PubMed1994

[Changes in neuroendocrine cells and immunocompetent cells in bronchiectasis].

Pulmonary endocrine cells and immunocompetent cells from the lungs of 35 subjects with bronchiectasis and in 10 normal controls were investigated by using immunohistochemical technique. The morphological and immunohistochemical characteristics of bronchus associated lymphoid tissue (BALT) of the lung were also studied. The number of calcitonin and serotonin immunoreactive pulmonary endocrine cells increased significantly in bronchiectasis as compared with those from control subjects. The number of IgA, IgG and IgM positive cells and UCHL1 positive cells were higher in the bronchial lamina propria in bronchiectasis than those in controls. These changes were most marked in hyperplastic BALT areas, which suggest that neuroendocrine and immune mechanisms may be involved in the pathogenesis of bronchiectasis.

Adult↗
PubMed1992

[The diagnosis of uterine leiomyosarcoma and endometrial stromal sarcoma].

The diagnostic problems in uterine smooth muscle tumors and endometrial stromal tumors are reviewed and discussed with analysis of 14 selective cases collected from the affiliated hospital. Data suggested that, in the differential diagnosis of benign and malignant uterine smooth muscle tumors, it is not comprehensive to use mitotic activity as the only criterion. Nuclear atypia and some other clinico-pathological features should be considered together, and, it is important to recognize the "mitotic active" leiomyoma which runs a benign course despite a high mitotic rate. In endometrial stromal sarcoma, the growth pattern and the extent of tumor spreading seem not closely correlated with the mitotic activity, nor the atypia, and, the clinical stage was considered as a significant reference in the prognosis. Thus, it is suggested that the differentiation of endometrial stromal sarcoma into low and high malignancy according to the mitotic rate alone is not the best reliable guide in evaluating the tumor behavior. It is emphasized that the extent of spreading of the tumor should be stated in the diagnosis. Immunohistochemical study revealed that the sex cord element in endometrial stromal sarcoma and other uterine tumors expressed a myogenous rather than an epithelial phenotype.

Diagnosis, Differential↗
PubMed1990

[Morphogenetic study on hyperplastic and neoplastic diseases of endocrine pancreas].

A morphologic study was conducted on nesidioblastosis, islet cell hyperplasia, adenomatous hyperplasia of islets of Langerhans and true islet cell adenoma with histochemical, immunohistochemical, electron microscopic and morphometric techniques. The results showed that the morphologic features of these four diseases were correlated with the development of pancreas and to a certain extent duplicated the process of fetal development. These findings seem to support the hypothesis that there exists a full spectrum of conditions ranging from the original nesidioblastosis to islet cell hyperplasia, adenomatosis and true islet cell adenoma.

Adenoma↗
PubMed1990

[Immunohistochemical study and lectin distribution of thyroid carcinoma originated from follicular epithelium].

97 cases of thyroid carcinoma originated from follicular epithelium were investigated by using histological and immunohistochemical techniques with special reference to lectin distribution. According to the WHO histological typing of thyroid tumours, these cases were divided into three categories as follows: papillary carcinoma of thyroid (PCT) 56, follicular carcinoma of thyroid (FCT) 31 and undifferentiated carcinoma of thyroid (UCT) 10. Results showed that three different kinds of thyroid carcinoma presented various hormone function and distribution of lectins. The positive rate of Tg immunoreactivity was significantly different between these three kinds of tumour, i.e. PCT greater than FCT greater than UCT. Additionally, the positive rate of T4 and T3 immunoreactivity was lower than that of Tg. Some Gastrin, SS and calcitonin positive cells were also recognized in carcinoma of thyroid. Lectin--binding rate of WGA, PNA, SBA and UEA to 97 cases of thyroid carcinoma and 9 cases of normal thyroid tissue revealed that different lectin had a selective binding activity to various types of thyroid carcinoma and normal thyroid cells. From the data obtained, it seemed that the morphological differentiation of thyroid carcinoma was in correspondence with difference of function, and the extent of cell differentiation may be closely related to the biological behavior of the tumour.

Adenocarcinoma↗
PubMed1988

Gossypol acetate-induced SCEs in spermatogonia and bone marrow cells of mice: dose-response relationships.

Gossypol acetic acid has been shown to have the effect of increasing the SCE frequencies in the spermatogonial cells of mice. This study further confirmed the genotoxic effects of gossypol acetic acid by investigating the dose-response relationships of gossypol acetic acid-induced SCEs in spermatogonial cells and bone marrow cells of mice. Twelve or over 12 mg/kg body weight of the dosage per day could increase the SCE frequencies of both bone marrow cells and spermatogonial cells. The increase of SCE frequency appeared to be directly correlated with the doses used at significant levels (p less than 0.001). Regression lines indicated that, in spite of cell type variation, the SCE induced was proportional to the dose of gossypol acetic acid.

Animals↗