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Biomedical subjects

K Tsutsui

Publications and source records attributed to K Tsutsui.

At least 217 records · Page 12Linked to original sources
PubMed1983

Identification of proteins interacting with newly replicated DNA in SV40-infected cells by UV-induced DNA-protein cross-linking.

Protein species interacting with newly replicated DNA were analyzed using a photo cross-linking technique. Nascent DNA was labeled in vitro with [alpha-32P]dCTP and BrdUTP in SV40-infected CV-1 cells made permeable with saponin. The labeled cells were then irradiated with UV light (254 nm) and were treated extensively with DNase I. Proteins with radioactive DNA tags were separated by SDS-PAGE and visualized by autoradiography. Among 10-15 proteins which were cross-linked, the proteins with apparent molecular weights of 16.5 K, 44 K, 82 K and those in the 94-140 K region appeared to be associated with newly replicated SV40 DNA. A pulse-chase experiment showed that the 82 K and 94-140 K proteins interacted with new DNA in a relatively localized region close to the replication fork. The 44 K protein was identified as the major viral capsid protein, VP1, using antiserum to SV40 capsid proteins. It was suggested that VP1 binds to nascent DNA shortly after DNA synthesis and migrates into chromatin maturation regions.

Animals↗
PubMed1983

Electron microscopic study on vaccinia virus release.

FL cells infected with the IHD-W strain of vaccinia virus were studied by scanning and transmission electron microscopy. A large number of naked virus particles were found to accumulate beneath the host cell plasma membrane and to protrude from the cell surface. It was seen in some cases that naked viral particles were released by budding not only from the cell surface but also from the surface of cytoplasmic packets which were seen along the cell periphery.

Amnion↗
PubMed1983

Feeding suppression induced by intra-ventricle III infusion of 1,5-anhydroglucitol.

1,5-Anhydroglucitol (1-DG) has been known as an antimetabolic glucose analogue. Using gas chromatography, 1-DG was found to be physiologically present in rat serum. In order to investigate its direct and long-term effects on feeding, 1-DG was infused during the light period into the rat third ventricle in doses of 3.0, 6.0 and 12.0 mumol/rat. Its effects were then compared to those of similarly applied 2-deoxy-D-glucose (2-DG). Following initial hyperphagia, both of these glucose-analogues produced suppressive effects on feeding during the subsequent day throughout the light and dark periods. On the third day after 2-DG injection reduction of feeding did not recover completely to the pretreatment baseline levels, but it did recover after 1-DG. Both 1-DG and 2-DG caused linear dose-related hypophagia, with the slope for 1-DG being about half of that for 2-DG. It is suggested that the delayed hypophagia which followed the initial hyperphagia produced by deoxyglucose was a result of sustained inactivation of the Na-pump due to intracellular ATP deficiency caused by accumulation of deoxy-glucose-6-phosphate.

Animals↗
PubMed1983

Susceptibility of Rous sarcoma virus-specific sequences integrated into SR-C3H/He mouse ascites sarcoma cell chromatin to DNase I and DNase II.

The susceptibility of Rous sarcoma virus (RSV) genomes integrated in mouse ascites sarcoma cells (SR-C3H/He cells) to DNase I and DNase II was investigated. Approximately half of the viral sequences were sensitive to DNase I and DNase II when 17% and 7.4% of the chromatin DNA was rendered acid soluble, respectively. The results suggest that newly acquired exogenous proviral sequences are integrated into both transcriptionally active and inactive regions of chromatin in cells lacking related endogenous viral sequences.

Animals↗
PubMed1983

Study on subacute toxicity of intravenous sorbitan trioleate (STO) in Wistar rats.

Subacute toxicity of STO was carried out using Wistar rats. STO was administered intravenously at dose levels of 12.5, 50.0 and 200.0 mg/kg for 35 days. No influence on general symptom, body weight, food and water consumption and urinalysis were observed. In 200.0 mg/kg group, the hematological examination revealed anemia corresponding to the histological findings of the bone marrow. Biochemical analysis displayed the significant increase and/or decrease of enzyme values in 200.0 mg/kg group. Morphology showed the swelling, vacuolization and granuloma of the spleen, hepatic granuloma, the increase of reticulum cells and granuloma in the bone marrow. Embolism and thrombus were also found in the pulmonary and tail veins probably due to an artifact caused by the i.v. injection. The toxicity of the STO were observed only in 200.0 mg/kg group of both sexes and any remarkable change other than physical effects were found in other groups under the above dosage. Accordingly, the maximal no-effect level of the STO in Wistar rats was considered to be 50.0 mg/kg.

Animals↗
PubMed1982

A protein with multiple heme-binding sites from rabbit serum.

A 93,000 molecular weight protein (HBP.93) which binds hemin and protoporphyrin IX with high affinity has been isolated from rabbit serum using affinity chromatography on hemin-conjugated agarose. The amino acid composition of this protein is unique in that the proline and histidine contents are remarkably high (16.6 and 9.9 mol %, respectively). A large increase in the absorbance of the Soret region arises from the heme-protein interaction. The spectrophotometric titration showed that the protein can bind 25-35 mol of hemin/mol of protein. The apparent dissociation constant was estimated to be 1-4 X 10(-7) M for hemin at pH 7.4 and approximately 10(-6) M for protoporphyrin IX at pH 9.2. The similarity of the difference spectrum of heme-HBP.93 complex to that of heme-hemopexin complex suggests that a bisimidazol-type coordination of heme iron is involved in the binding. The extremely high capacity of HBP.93 to bind heme is also demonstrated by a large increase in the sedimentation velocity of the protein upon heme binding. The native heme-protein complex migrates faster than the heme-free protein in a polyacrylamide gel at pH 8.8; the increased mobility appears to be due to the charge on the carboxyl groups of the bound heme. Although the use of a hemin-agarose column has failed to reveal a protein of similar size and heme affinity in the sera of a number of other species, including man, the heme-binding properties and high histidine level of the human alpha 2-histidine-rich glycoprotein raise the possibility that the two proteins are related.

Amino Acids↗
PubMed1982

The turnover of molecular species of phosphatidylinositol in Ehrlich ascites tumor cells.

It has been shown previously the 32Pi is incorporated into phosphatidylinositol 30 times faster than into the other phospholipids classes in Ehrlich ascites tumor cells, whereas [1-14C] glycerol is incorporated at almost the same rate (Waku, K., Nakazawa, Y. and MOri, W. (1976) J. Biochem. 79, 407-411). It was therefore suggested that there is a recirculating system (phosphatidylinositol leads to diacylglycerol leads to phosphatidic acid leads to CDP diacylglycerol leads to phosphatidylinositol) of phosphatidylinositol in Ehrlich ascites tumor cells. In this work, 32Pi or [1-3H] glycerol was injected into the peritoneal cavity of mice bearing Ehrlich ascites tumor cells from which the lipids were extracted after selected periods. Phosphatidylinositol was prepared and fractionated in the form of dimethylphosphatidic acid into six molecular species by AgNO3-impregnated TLC. The specific radioactivities of the fractionated species were determined. 32Pi was incorporated into diene molecular species and [1-3H] glycerol into monoene species with a higher rate than the other species and both precursors were incorporated into tetraene species rather slowly. 32P/3H values appeared to be at almost the same for each molecular species, although monoene species showed slightly lower values. These results suggest that there could be a recirculating of the phosphorylinositol moiety in each of the molecular species of phosphatidylinositol.

Animals↗
PubMed1982

Theophylline disrupts diurnal rhythms of humoral factors with loss of meal cyclicity.

To test the possibility that theophylline induced circadian disappearance of food intake might depend upon rhythmic disruption of blood glucose, insulin and free fatty acids (FFA), theophylline was administered chronically. This markedly lengthened postprandial intermeal intervals during the dark, and induced approximately identical intermeal intervals and identical meal sizes in the light and dark periods. In contrast to the clear light-dark dependent oscillations of serum glucose, insulin and FFA in the controls, the theophyllinized rats lost circadian fluctuation of each of these three chemical substances. Further, theophyllinized rats, unlike controls, had no time-dependent fluctuation in the levels of these substances at -120, -60 or -15 min preceding the onset of the first meal before the dark. These findings, together with previous reports, explain the disappearance of nocturnal feeding rhythm in theophyllinized rats in terms of functional destruction of circadian regulation in the hypothalamus which modulate the production of chemical determinants of food intake.

Animals↗
PubMed1981

[The correlation between serum angiotensin I-converting enzyme activity and the renin-angiotensin-aldosterone system in hypertensive patients (author's transl)].

In order to investigate the role and origin of serum angiotensin I-converting enzyme activity (ACEA) in hypertension, the correlation between serum ACEA and the renin-angiotensin-aldosterone system was evaluated in hypertensive patients of whom 36 had essential hypertension, five had hypertension associated with chronic renal failure, three had renovascular hypertension, and one had primary aldosteronism. Serum ACEA was 17.0 +/- 3.3 U (mean +/- sd) in the normotensive control, 20.1 +/- 7.1 U in patients with essential hypertension, 11.6 +/- 3.4 U in patients with chronic renal failure, 31.7 +/- 1.1 U in patients with renovascular hypertension, and 9.7 U in primary aldosteronism in a recumbent state. There was a significant correlation between serum ACEA and plasma renin activity (PRA) (r = 0.615, p less than 0.001, n = 45) and plasma aldosterone concentration (PAC) (r = 0.599, p less than 0.001, n = 34) in a recumbent state. However, there was no significant correlation between serum ACEA and mean blood pressure. Serum ACEA elevated with furosemide and an upright posture significantly correlated with elevation in PRA (r = 0.369, p less than 0.05, n = 32) but did not significantly correlate with elevation in PAC. It is suggested, therefore, that the kidney is the suspected source of the plasma activity of the enzyme and that serum ACEA plays a possible role in the regulations of blood pressure and electrolyte metabolism modulating the renin-angiotensin-aldosterone system.

Adult↗