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Biomedical subjects

K Segawa

Publications and source records attributed to K Segawa.

At least 181 records · Page 10Linked to original sources
PubMed1980

Antisera from mice and rats incubated with syngeneic Rous sarcoma cells.

CDF1, (BALB/c X DBA/2)F1, mice were repeatedly inoculated with transplantable mouse Rous sarcoma (SR-CDF1) cells which were half-killed by 60Co-irradiation beforehand to attain prolonged immunization. The sera obtained from these mice contained antibodies against the src and gag gene products of Rous sarcoma virus (RSV). On the other hand, Fischer rats inoculated with syngeneic rat Rous cells transformed by Bryan high titer strain of RSV (BH(-)-3Y1) produced antibodies against the gag gene products but not the src gene product of RSV. As a substrate for the protein kinase associated with the src gene product, mouse IgG was found to be much less efficient than rabbit IgG when assayed in immunoprecipitates. Several other properties of the mouse antiserum were described.

Alpharetrovirus↗
PubMed1979

An experimental study on histamine H2-receptor antagonist on calcium, gastrin and histamine induced gastric acid secretion in rat.

The suppressive effect of histamine H2-receptor antagonist, cimetidine, on gastric secretion was investigated in Ghosh-Schild rat. The study above was done in basal state under infusing normal saline (1 ml/h) and stimulated state by histamine-di-chloride (3.5 mg/kg-h), tetragastrin (50 mcg/kg-h) or calcium chloride (4 mg/kg-h). Dose related increase of cimetidine (1.7, 3.5, 7.0 and 14.0 mg/kg-h) were observed and correlated with the degree of inhibition of acid secretion. Cimetidine had a potent inhibitory activity on either basal and stimulated acid output by the agents above. Basal acid secretion was completely abolished by 3.5 mg/kg-h of cimetidine to the level of anacidity. The degree of inhibition by the same dose of cimetidine was different among the agents used as stimulant on acid secretion and it followed in the order of calcium, gastrin and histamine subsequently. This study indicated that histamine H2-receptor participated the gastric secretion induced by either gastrin or calcium other than histamine itself. This fact indicated the important role of endogenous histamine in gastric secretion induced by calcium and gastrin.

Animals↗
PubMed1978

Protein kinases and their protein substrates associated with chromatin and ribosomes in SV40-transformed rat cells.

The level of endogenous protein phosphorylation in non-histone chromosomal and ribosomal wash proteins is 7--10 times greater in SV40-transformed rat cells than in untransformed parental cells. Protein kinase activity in these proteins was fractionated by either phosphocellulose or DEAE-cellulose chromatography. One major and one minor component were detected in non-histone proteins and only one component in ribosomal wash proteins when the activity in each fraction was measured with an exogenous substrate, casein. These enzymes prefer casein to whole histone as substrate and are cyclic AMP-independent. The enzyme activity in a major peak of non-histone proteins and in ribosomal wash proteins measured with casein as substrate is 3 times greater in transformed cells than in untransformed cells, whereas pH optimum, cation requirements and apparent Km values for casein and ATP are identical or very similar in the two cell types. No significant phosphatase was detected in non-histone and ribosomal wash proteins from the two types of cell. The patterns of endogenous protein phosphorylation in these protein fractions analysed by gel electrophoresis are significantly different between these cells. These results suggest that the high level of endogenous protein phosphorylation in non-histone and ribosomal wash proteins from SV40-transformed cells is caused mainly by the increased activity of protein kinase and the nature of protein substrates.

Animals↗
PubMed1978

The effect of motilin on the gastrointestinal propulsion in rats.

We studied the gastrointestinal propulsion in unanaesthetized rats by 51Cr method that permits the simultaneous determination of two functions of the gastric emptying and the intestinal propulsion. The results obtained are as follows: 1) The semi-logarithmic presentation of the gastric emptying showed a linear relationship with the time. 2) When synthetic motilin was subcutaneously injected at the dose of 1 microgram/kg, the gastric emptying was promoted to a statistically significant extent.

Animals↗
PubMed1978

Phosphorylation of chromatin- and ribosome-associated proteins in cells transformed by adenovirus, murine sarcoma virus, and methylcholanthrene.

Endogenous protein phosphorylation in chromatin and ribosomes of monkey, mouse, and rat cells transformed by DNA, RNA tumor viruses, and a chemical carcinogen revealed the association of a protein of approximately 90,000 daltons (90K), which is highly phosphorylated in vitro. Peptide map analysis showed that the 90K proteins associated with these organelles of various transformed cells are similar irrespective of the species of cells and transforming agents. This species of protein could not be detected, or was scarcely detected, by phosphorylation in chromatin and ribosomes of untransformed cells and in revertants of transformed cells. These results suggest that the alteration in the pattern of endogenous protein phosphorylation in these organelles is closely related to the transformed state of cells.

Adenoviruses, Human↗
PubMed1977

The nocturnal intragastric pH in EEG sleep stages in peptic ulcer patients.

In 10 peptic ulcer patients, 5 duodenal ulcer and 5 gastric ulcer patients, the relation of nocturnal intragastric pH to EEG sleep stages was examined. The nocturnal intragastric pH was monitored by pH-measuring telemeter and sleep stages were recorded simultaneously by electroencephalography throughout the night. The EEG sleep stages were classified after the criteria of Dement and Kleitman. The average of intragastric pH level at each sleep stage was higher in gastric ulcer than the duodenal ulcer. The intragastric pH level became low as the patients' sleep advanced to deep stage. This tendency was more likely in duodenal ulcer patients than the gastric ulcer patients, which indicated that the cephalic phase might play an important role in the pathogenesis of hyperacidity in duodenal ulcer.

Adult↗
PubMed1977

The further investigation on the gastric acid secretion in the primary hyperparathyroidism.

The gastric acid output was studied in the 11 patients of hyperparathyroidism before and after parathyroidectomy. The gastric acid output before operation was almost equal to the normal control in our hospital. After the correction of serum calcium by parathyroidectomy, the gastric acid output and serum gastrin were decreased. The decreased gastric acid output was recovered as the days passed since operation and approached to the preoperative level. The acid output in hyperparathyroidism was less in the case whose activity of alkaline phosphatase was more, which suggested that the calcium deposition on gastric mucosa might damage the parietal cell as the result of long lasting hypercalcemia.

Adolescent↗
PubMed1977

Simian virus 40 gene A regulates the association between a highly phosphorylated protein and chromatin and ribosomes in simian virus 40-transformed cells.

The species of proteins associated with chromatin and ribosomes of simian virus 40 (SV40)-transformed and untransformed monkey, mouse, and rat cells have been compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after phosphorylation of these proteins either in vivo or in vitro. In vitro phosphorylation was carried out by protein kinase associated with these organelles and [gamma-(32) P]ATP as the phosphoryl donor. The reaction products contained both phosphoserine and phosphothreonine in approximately equal amounts. The electrophoretic analysis of the phosphorylated proteins revealed that the highly phosphorylated protein with a molecular weight of approximately 90,000 (90K protein) was associated with chromatin and ribosomes from transformed cells but not from untransformed cells. The 90K protein could be extracted from chromatin and ribosomes with 0.5 to 1.0 M NaCl or KCl. The 90K protein was still associated with the runoff ribosomes prepared by the puromycin reaction of the post-mitochondrial supernatant in the protein-synthesizing system. In vitro phosphorylation of chromatin and ribosomes from SV40 tsA-transformed mouse and rat cells indicated that the amounts of 90K protein associated with these organelles decreased greatly when the cells were cultivated at the restrictive temperature. A similar temperature-dependent decrease in the amount of (32)P-labeled 90K protein was observed in nonhistone chromosomal and ribosome-associated protein fractions prepared from SV40 tsA-transformed cells labeled with [(3)H]leucine and [(32)P]orthophosphate in vivo. In vitro phosphorylated 90K protein in nonhistone chromosomal and ribosome-associated proteins extracted with high salt was not immunoprecipitated with anti-SV40 T sera.

Adenosine Triphosphate↗
PubMed1975

Isolation and chemcial properties of A-protein from filamentous phage Fd.

A-Protein was isolated from a purified male-specific filamentous phage fd particle. A-Protein has a molecular weight of approximately 60,000 daltons, as estimated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The amino-terminal residue was glycine as determined by the dansylation technique. Amino acid analysis showed that histidine, arginine, and cysteine, which are not contained in B-protein, are present in A-protein.

Amino Acids↗