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Biomedical subjects

T R Chen

Publications and source records attributed to T R Chen.

At least 55 records · Page 3Linked to original sources
PubMed1977

Fluorescent C bands of human chromosomes with 33 258 Hoechst stain.

Air-dried preparations of human metaphase chromosomes normally exhibit a Q band fluorescence pattern with 33 258 Hoechst stain while the C band regions of 1,9,16, and most acrocentric short arms appear dull. If these stained and mounted slides are stored at room temperature in the dark for several days, a spontaneous change from C-negative to C-positive band some times occurs. We postulate that the pH of the buffered saline mounting medium during storage of the slides causes the C band shift since the results can be duplicated experimentally by lowering the pH of the mounting buffer from 5.5 to 4.0.

Buffers↗
PubMed1976

Correlation of in vivo malignancy with in vitro properties of human-mouse hybrid cells.

The in vivo tumorigenicity of malignant mouse-nonmalignant human somatic cell hybrids was correlated with the in vitro characteristics. The renal adenocarcinoma mouse cell line RAG and the normal, diploid human cell line Wl-38 were used as the fusion parents. Five independent RAG Wl 38 hybrid clones were tested for concanavalin A (Con A) agglutination patterns, in vitro invasiveness, and tumor formation in immunosuppressed mice. Tests on the parental lines showed that RAG cells agglutinated at much lower levels of Con A than the Wl-38 cells. RAG cells overgrew Wl-38 cells in the in vitro invasiveness assay. RAG cells readily formed tumors in untreated adult or young immunosuppressed mice, whereas the Wl-38 cells did not. The five hybrid clones were all similar, since they had Con A agglutination levels intermediate to those of both parents, though patterns were more "tumor-like", overgrew the Wl-38 cells in the invasiveness assay, and formed tumors in immunosuppressed mice.

Adenocarcinoma↗
PubMed1975

The possibility of latent centromeres and a proposed nomenclature system for total chromosome and whole arm translocations.

Translocations involving entire chromosomes or whole chromosome arms may not necessarily require deletion of a centromere. Conceivably, in the process of centromeric or telomeric fusion or of fusion of a centromere with a telomere, centromeric inactivation may occur, thus preserving both centromeres--one functional, the other latent--in the resultant translocation chromosome. If such latent centromeres exist and, in addition, are capable of being reactivated, it would explain how additional functional centromeres are acquired in the reverse process of chromosomal fission or fragmentation. A system of nomenclature is proposed for identifying the origin and nature of these chromosomal rearrangements.

Animals↗
PubMed1973

Chromosome assignments in man of the genes for two hexosephosphate isomerases.

Thirty-seven clones of somatic cell hybrids between human and mouse cells were examined for retention of human chromosomes and expression of human constitutive enzymes. Human glucosephosphate isomerase and chromosome F-19 were retained or lost concordantly, as were human mannosephosphate isomerase and chromosome C-7. The genes for the enzymes are thus assigned to these two chromosomes.

Animals↗
PubMed1972

Assignment of three human genes to chromosomes (LDH-A to 11, TK to 17, and IDH to 20) and evidence for translocation between human and mouse chromosomes in somatic cell hybrids (thymidine kinase-lactate dehydrogenase A-isocitrate dehydrogenase-C-11, E-17, and F-20 chromosomes).

Independently derived man-mouse somatic cell hybrids and their derivative subclones show a positive correlation between the expression of human lactate dehydrogenase A subunits and the occurrence of the human C-11 chromosome. Data are also presented that confirm the previously reported linkage of the thymidine kinase locus to the E-17 chromosome. A translocation of the E-17 chromosome provides presumptive evidence for the assignment of the thymidine kinase locus to the long arm segment of the E-17 chromosome. This translocation also provides evidence for translocation between man and mouse chromosomes in somatic cell hybrids. A presumptive association between the human phenotype for isocitrate dehydrogenase and the human F group is also described. Identification of specific human chromosomes was achieved by the application of several new cytological techniques: measurement of chromosome arm length, in situ annealing with mouse satellite complementary RNA, constitutive heterochromatin staining with Giemsa, and quinacrine mustard fluorochromatic staining.

Animals↗