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Biomedical subjects

I Nisida

Publications and source records attributed to I Nisida.

9 recordsLinked to original sources

Co-existence of inhibitory and stimulatory factors modulating cell proliferation in rat liver cytoplasm.

Factors that inhibit and stimulate cell proliferation were found to coexist in rat liver supernatant. The inhibitory and stimulatory factors were separated by ethanol fractionation. Both factors were sensitive to heat- and trypsin-treatment. The activity of the inhibitor was diminished by partial hepatectomy. The inhibitor from normal livers inhibited DNA and RNA synthesis in the L-cell system, but the same fraction from regenerating livers caused little or no inhibition of nucleic acid synthesis. The stimulatory factor from regenerating livers had a stronger effect on cell proliferation than that of normal livers. Furthermore, the inhibitor from normal livers depressed DNA synthesis in vivo in regenerating livers.

Animals

Partial purification and biological activities and properties of chick growth factors.

Cellular stimulating factors on cell proliferation in the supernatants of chick embryo carcases and adult muscles were studied. There were plural stimulating factors in embryonic and adult muscular supernatants that promoted cell proliferation without any supplement of sera and other materials. Salting-out methods with ammonium sulfate, ethanol fractionation, and isoelectric precipitation were used to isolate the stimulating factors, and these three methods proved the presence of plural stimulants on cell proliferation in the supernatants of chick embryo and adult muscles. The stimulants had altered physico-chemical properties and biological activities due to embryological development. The embryonic stimulants enhanced the synthesis of DNA and protein remarkably, and RNA synthesis in whole cell systems slightly. The muscular stimulants enhanced protein synthesis without any stimulation of DNA and RNA synthesis. Partial purification of the stimulants from the ethanol fractions was performed by DEAE-cellulose chromatography and Sephadex gel chromatography.

Animals

Heat stable cell growth inhibiting factor isolated from rat liver microsomes.

A heat stable cell growth inhibiting factor was isolated from rat liver microsomes by hot salt extraction, ethanol fractionation and the hot phenol method. The factor was contained in the RNA fraction (designated as mhRNA). mhRNA inhibited the growth of mouse fibroblast (L-929) cells at a relatively low concentration (55 microgram/ml of culture medium). The molecular weight of mhRNA was about 27,000 and the base composition was guanine and cytosine rich.

Animals

Plural growth factors in the supernatant of embryos and adult muscles of chickens.

An attempt was made to isolate the cell proliferation stimulation factors in the supernatant of embryo carcases and adult muscles of chickens. Evidence was obtained for the presence of at least two or more stimulating factors in both the embryonic and adult muscular supernatants. These factors did not require a supplement of sera or other supporting agents. Furthermore, the use of the salting-out method with ammonium sulfate revealed two or more growth stimulants in the supernatant of chick cells.

Animals

Purification and some characteristics of liver cytosol cornin, an antimitotic substance from rat liver cytosol.

Further purification and characterization are reported on rat cytosol cornin (RLCC), an antimitotic substance. Fraction I (purified RLCC) was purified more than 10-fold from crude RLCC with Sephadex G-50 column chromatography and showed a remarkable inhibitory effect on division of inseminated sea urchin eggs and mouse fibroblast cells. Fraction I was observed as one spot, and the molecular weight was estimated to be about 25,000 by thin layer gel filtration. Fraction I contained protein (92%) and RNA (8%), but the antimitotic activity was scarcely affected by treatment by pancreatic RNase. The protein of Fraction I was separated into two bands by SDS-polyacrylamide gel electrophoresis, and the molecular weight was estimated as 10,000 and 15,000, respectively. The 50% inhibition dose of Fraction I on the first division of inseminated sea urchin eggs and on proliferation of mouse L cells was about 2.5 X 10(-5) g/ml and 5 X 10(-4) g/ml, respectively. The yield of fraction I was about 35 mg from 100 g rat liver.

Amino Acids

Cell proliferation stimulating factors in the supernatant of embryos and adult muscles of chickens of the same strain.

Stimulating factors of cell proliferation were extracted from the supernatant of embryos and adult muscles of chickens of the same strain. The stimulating activity and physicochemical properties of these factors were altered after embryological development. The embryonic factors were about 3.5 times more effective than the muscular factors. These factors might be useful in analysis of the regulatory mechanisms of cell proliferation.

Animals