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Biomedical subjects

K Toyoshima

Publications and source records attributed to K Toyoshima.

335 records · Page 19Linked to original sources
PubMedDate not supplied

Similarity of protein encoded by the human c-erb-B-2 gene to epidermal growth factor receptor.

A novel v-erb-B-related gene, c-erb-B-2, which has been identified in the human genome, maps to human chromosome 17 at q21 (ref. 40), and seems to encode a polypeptide with a kinase domain that is highly homologous with, but distinct from, that of the epidermal growth factor (EGF) receptor. The c-erb-B-2 gene is conserved in vertebrates and it has been suggested that the neu gene, detected in a series of rat neuro/glioblastomas, is, in fact, the rat c-erb-B-2 gene. Amplification of the c-erb-B-2 gene in a salivary adenocarcinoma and a gastric cancer cell line MKN-7 suggests that its over-expression is sometimes involved in the neoplastic process. To determine the nature of the c-erb-B-2 protein, we have now molecularly cloned complementary DNA for c-erb-B-2 messenger RNA prepared from MKN-7 cells. Its sequence shows that the c-erb-B-2 gene encodes a possible receptor protein and allows an analysis of the similarity of the protein to the EGF receptor and the neu product. As a consequence of chromosomal aberration in MKN-7 cells, a 4.6-kilobase (kb) normal transcript and a truncated 2.3-kb transcript of c-erb-B-2 are synthesized at elevated levels. The latter transcript presumably encodes only the extracellular domain of the putative receptor.

Amino Acid Sequence↗
PubMedDate not supplied

Correlation between metastatic potency and the down-regulation of E-cadherin in the mouse hepatoma cell lines G-1 and G-5.

Cell-cell adhesiveness, involving the adherens junction system including homophilic adhesion of cadherin and intracellular catenins, is a critical factor for tumor cell invasion and metastasis. We evaluated the levels of E-cadherin and beta-catenin in hepatoma cell sublines with high and low metastatic capacities. Stimulation of these cells with serum growth factors for more than 3 h after 24 h of starvation caused decreases in levels of E-cadherin and beta-catenin in the subline with high metastatic capacity, G-5. In contrast, no significant changes were observed in the subline with low metastatic capacity, G-1. Concomitantly with the decreases in E-cadherin and beta-catenin levels, G-5 cells were dissociated and detached from the culture dish, although G-1 cells again showed no morphological alterations. These in vitro results reflected the in vivo metastatic potencies of these hepatoma sublines, and further suggested the importance of the adherens junction system in determining metastatic potency of these parenchymal tumor cell lines as in epithelial/endothelial tumors.

Animals↗
PubMedDate not supplied

Correlation between trimester of fetal wastage and anti-cardiolipin antibody titer.

The existence of circulating lupus anticoagulant and anti-cardiolipin antibodies (ACA) has been reported to be associated with recurrent fetal loss. We used an enzyme-linked immunosorbent assay (ELISA) for detection of ACA in plasma samples from 104 women with a history of recurrent fetal loss. The normal range of the ACA level was defined as less than 6 GPL (IgG anti-cardiolipin) units (n = 100 normal plasma samples). Nine women (9.7%) were positive for ACA. The population was divided into two groups on the basis of medical history, and analysis revealed that 42.8% (3/7) of the group of patients with at least one fetal loss in the second or third trimester were positive for ACA; their mean ACA titer was 34 GPL units.

Abortion, Spontaneous↗