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Biomedical subjects

S Shin

Publications and source records attributed to S Shin.

At least 235 records · Page 13Linked to original sources
PubMed1979

Production of anti-glucagon sera with a C-terminal fragment of pancreatic glucagon.

The C-terminal region-sepcific anti-glucagon sera were raised in rabbits using as immunogen, and conjugate of BSA and a C-terminal fragment of pancreatic glucagon. The hapten was prepared by trypsin digestion of the glucagon, which was proved to be a 1:3 mixture of glucagon (18--29) and (19--29). Six rabbits were immunized by subcutaneous injection of an emulsion of the conjugate with complete Freund's adjuvant and five of the rabbits produced antibodies to the glucagon (GC-1, GC-2, GC-3, GC-5 and GC-6). For comparison, rabbit antisera were also produced against glucagon polymer (GA-10) and syrupy glucagon fibrils (PGA-2). All these antisera as well as the pancreatic glucagon-specific antiserum 30 K were characterized with dog gut-extract (gut-GLI) and glucagon-related peptide fragments in the radioimmunoassay systems. The assay systems utilized 125 I-monosubstituted pancreatic glucagon as tracer and human mono-component glucagon as standard. All sera of the GC-series crossreacted with the dog gut-extract very weakly and antisera GC-5 and GC-6 exhibited the lowest crossreactivities with the extract, which were shown to be as low as that of 30k. Characterization of the antiserum GC-5 with purified glucagon related fragments indicated that the major antigenic determinant located exactly in the C-terminal region of glucagon. The present results clearly showed high efficiency of the use of the glucagon C-terminal fragment as hepatenic immunogen in obtaining the C-terminal region-specific, i.e., pancreatic glucagon-specific antisera.

Animals↗
PubMed1978

An approach to defining the etiology of animal abortions.

Attempts to define the etiology of abortions on a regular continuing basis have been few, and largely unsuccessful. Problems of such a project include cost, difficulty of securing satisfactory samples, a laboratory organization of sufficient breadth, capacity and dedication to perform and interpret the necessary examinations, knowledgeable cooperation of the practitioner, and past reliance on isolated findings substituting for sound criteria for diagnosis. A program was created which was intended to overcome the difficulties. The plan was so constructed as to permit addition or removal of procedures as indicated.

Abortion, Veterinary↗
PubMed1977

Growth of murine sarcoma virus-transformed rat kidney cells in nude mice: absence of induction of host endogenous viruses.

Clonal isolates of the normal rat kidney cell line (NRK) transformed by a defective murine sarcoma virus (Kirsten strain) were injected into nude mice of BALB/c background to determine whether the growth of these cells as tumors was accompanied by the induction of host endogenous type C viruses. All the virus-transformed clones produced rapidly growing tumors in nude mice, but neither the induction of mouse endogenous viruses nor the rescue and spread of the transforming sarcoma virus were observed during the growth of tumors. The degree of expression of the tumor virus structural proteins in the transformed cells did not determine the cellular phenotype with regard to tumorigenicity in nude mice, nor did it modify the cellular growth properties in vitro. Consistent with earlier observations with simian virus 40-transformed mouse and rat cells, the ability of sarcoma virus-transformed NRK cells to initiate tumor growth in nude mice appeared to be correlated with anchorage-independent growth in vitro.

Animals↗
PubMed1977

Biosynthesis of neurophysin proteins in the dog and their isolation.

Neurophysin (Np) is generally found in close association with vasopressin and oxytocin in the hypothalamo-neurohypophyseal complex. Dog neurophysin I and II have been isolated from fresh and frozen posterior pituitaries. The proteins were characterized on the basis of disc electrophoresis, immunological properties, amino acid composition and partial sequence determination. The amino terminal sequence of dog Np I is Ala-Ala-Leu-Asp-Leu-Asp-Val-Arg-Gln-Cys-Leu-Pro-Cys-Gly-Pro-Gly-Gly-Gln-Gly-while that of dog Np-II is Ala-Met-Ser-Asp-Leu-Glu-Leu. The dog Np I appears to be metabolically less stable than Np II. Isotope experiments with [35S]cystine or 3H-labeled amino acids using a design of "in vitro pulse and in vitro chase" as well as "in vivo pulse and in vivo chase," added further confirmation of the capability of the hypothalamic neurosecretory cells to synthesize concomitantly precursors of Np and vasopressin. The radioactively labeled precursors were converted to Np-like protein and vasopressin, both of which were isolated.

Amino Acid Sequence↗
PubMed1976

Enhance anchorage independence and tumorigenicity of aneuploid Chinese hamster cells with nearly doubled chromosome complements.

The role of a cell's chromosome complement in its tumorigenic and anchorage-independent growth properties in vitro was investigated by injecting a Chinese hamster cell line and its subclones into immunodeficient nude mice and by plating the cells in a semisolid medium containing methylcellulose. The parental WOR-6 cell clone originally consisted of 89% 1s cells and 11% cells with a nearly double (2s) complement. Tumors that developed from WOR-6 were found to consis entirely or primarily of cells with near 2s chromosome complements. Subclones of WOR-6 that contained only 1s cells rarely produced tumors in nude mice, even at high inoculum doses, whereas clones containing a high fraction of 2s cells were consistently tumorigenition, serial passage of WOR-6 cells in semisolid medium resulted in selective enrichment for near 2s cells and, concomitantly, greatly enhanced tumorigenicity. Analyses of G-banded chromosomes revealed that the 1s cells of the WOR-6 parental clone, which has a modal chromosome number of 21 and a range of 18 to 23, is completely or partially monosomic for some chromosomes and trisomic for others. The 2s cells, selected both in vivo through growth as tumors in nude mice and in vitro in semisolid medium, appeared to have resulted from preferential duplication of certain chromosomes of the 1s cells. Our results therefore suggest that cells which develop multiple copies of selected genes, while remaining functionally hemizygous for other loci, acquire an enhanced anchorage-independent growth potential in vitro and increased tumorigenicity. This conclusion is consistent with the observation that cellular tumorigenicity is correlated with anchorage independence (Rreedman and Shin, 1974) and leads support to OHNO'S (1974) suggesting that aneuploidy is a possible means employed by cells to express recessive phenotypes and increase their tumorigenicity.

Aneuploidy↗
PubMed1971

Mitotic separation of two human X-linked genes in man--mouse somatic cell hybrids.

SIX INTERSPECIFIC SOMATIC HYBRID CELL LINES WERE DERIVED FROM A MOUSE LINE DEFICIENT IN HYPOXANTHINE: guanine phosphoribosyltransferase (HGPRT) and human diploid cells with normal enzyme activity. Human HGPRT was present in all six hybrids and the clones derived from them. However, in two of the six, and in some clones from another two, human glucose-6-phosphate dehydrogenase (G6PD) was absent. Since the structural loci for both these enzymes are X-linked in man, these findings suggest that these two loci have separated quite frequently through chromosome breakage and that they must be rather far apart on the X chromosome.

Animals↗
PubMedDate not supplied

The effect of experimental cystitis and iatrogenic blood contamination on the urine protein/creatine ratio in the dog.

The effect of experimentally induced cystitis and iatrogenic blood contamination on the urine protein/creatinine ratio (U P/C) was evaluated in 17 dogs. Before they were included in the study, all dogs were judged to be healthy on the basis of physical examination, serum concentrations of urea nitrogen and creatinine, complete urinalysis, and a U P/C less than 0.4. A single urine sample was contaminated with increasing quantities of canine fresh whole blood (PCV = 42%; total protein = 6.2 g/dl). When added blood was equal to or greater than 25% of the total urine sample volume, the U P/C exceeded 3.5, a finding consistent with nephrotic range proteinuria. When added blood was 10% of the total urine sample volume, the U P/C was less than 1.8. Eleven Beagles underwent routine laparotomy during which a cystotomy was done. The median U P/Cs on postoperative days 1 and 2 were significantly increased compared with preoperative values (P less than 0.05); no U P/C exceeded 2.0. Renal biopsies performed on postoperative day 3 eliminated renal proteinuria as a source of urine protein. Five dogs had bacterial cystitis experimentally induced. At 72 and 96 hours after bacterial inoculation, the median U P/Cs were significantly increased (P less than 0.05); individual values ranged from 1.5 to 40.8. Renal biopsies performed between 5 and 6 days after inoculation eliminated renal proteinuria as a source of urine protein. Cytologic evaluation of urine sediment in each group did not correlate with the magnitude of the increase in the U P/C. The U P/C significantly increased in each model of lower urinary tract inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗