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Biomedical subjects

T Furuta

Publications and source records attributed to T Furuta.

At least 397 records · Page 22Linked to original sources
PubMed1983

Studies on drug metabolism by use of isotopes XXVII: urinary metabolites of rutin in rats and the role of intestinal microflora in the metabolism of rutin.

Analysis of urinary metabolites of orally administered rutin (I) labeled with deuterium [( 2',5',6'-2H]rutin, rutin-d) was carried out by GLC-MS. In rat urine, 3-hydroxyphenylacetic acid (III), 3-methoxy-4-hydroxyphenylacetic acid (IV), 3,4-dihydroxyphenylacetic acid (V), 3,4-dihydroxytoluene (VI), and 3-(m-hydroxyphenyl)propionic acid (VIII) were identified as rutin metabolites and were differentiated from the corresponding endogeneous compounds. Unchanged I and quercetin (II) were not present in the urine. Rutin-d was injected intraperitoneally in rats, administered orally to neomycin-treated rats, and incubated in vitro with the intestinal contents of rats. The experiments suggested the involvement of intestinal microflora in the metabolism of orally administered I.

Animals↗
PubMed1983

Small liver cancer.

We report eight cirrhotic patients with liver cancer of less than 2 cm in diameter, and who were successfully treated by surgery. The sensitivities of diagnostic procedures for small lesions showed that alpha-feto-protein (AFP) was 75 per cent, radionuclide scanning 25 per cent, CT 33 per cent, ultrasonography 40 per cent and angiography 88 per cent. Serial measurement of AFP appears to be the most helpful for detection of hepatocellular carcinoma at the early stage, particularly in cirrhotic patients. Although hepatic imagings are of limited value for small hepatic tumors, those tools are often useful as a back-up for the routine tests but not for initial procedures. It should also be kept in mind that hepatic arteriography performed in the high risk group often leads to detection of small cancers. In cirrhotic patients with small hepatocellular carcinoma, surgical resection should be done, providing the clinical status and hepatocellular reserve are adequate.

Carcinoma, Hepatocellular↗
PubMed1983

Role of primers in glucan synthesis by glucosyltransferases from Streptococcus mutans strain OMZ176.

The effects of isomaltosaccharides of various molecular weights (isomaltose to dextran T2000) on glucan synthesis by a water-soluble glucan-synthesizing glucosyltransferase enzyme (GTase-S) and a water-insoluble glucan-synthesizing enzyme (GTase-I), both from Streptococcus mutans OMZ176, were examined. The activity of GTase-S was not affected by the addition of the isomaltosaccharides, but GTase-I was stimulated increasingly by isomaltosaccharides with degrees of polymerization more than 10. The GTase-I activity first increased and thereafter decreased slightly with increasing amounts of a soluble dextran. Maximal stimulation occurred at concentrations in the range 0.1 to 0.2 mg ml-1, when dextran T10 was used as a primer. The rate of glucan synthesis was highly enhanced by the combined action of GTase-S and GTase-I. The profile of the net activity of GTase-I in the presence of various amounts of GTase-S was similar to that of GTase-I in the presence of increasing amounts of an exogenous dextran. These results collectively suggest that soluble glucan produced by GTase-S from sucrose acts as an intrinsic primer for the glucan synthesis by GTase-I, indicating the contribution of autopriming in glucan synthesis by crude GTase of S. mutans.

Dextrans↗
PubMed1983

Production of monoclonal antibody against a glucosyltransferase of Streptococcus mutans 6715.

A mouse hybrid cell line secreted monoclonal antibody which reacted specifically with Streptococcus mutans 6715 (serotype g) glucosyltransferase (GTase)-synthesizing water-insoluble glucan and inhibited with enzyme reaction. The antibody was cross-reactive with GTase of serotype d but not with GTase of other serotypes of S. mutans when an enzyme-linked immunosorbent assay was used.

Animals↗
PubMed1983

The electrophysiological actions of lidocaine on ischemic ventricular muscle as compared with procainamide.

For the purpose to evaluate the effects of lidocaine on the ventricular arrhythmias occurring as complications of acute myocardial ischemia or infarction, the electrophysiological actions of lidocaine were estimated, as compared with those of procainamide, on the right ventricular papillary muscle of the rabbit heart superfused with hypoxic, hyperkalemic and/or acidic Krebs-Ringer solution. Lidocaine (1 to 5 x 10(-5)M) and procainamide (1.7 to 3.4 x 10(-5)M) depressed the maximum rate of action potential upstroke (Vmax) and prolonged both of the effective refractory period (ERP) and the diastolic interval needed for the premature Vmax to recover to 98% in magnitude of the basic Vmax (98% recovery time) dose-dependently, without decreasing the resting potential. Among the ischemic components, low pH (pH 6.9) and high potassium (10 mM) extracellular environments potentiated the depressant actions of lidocaine in synergic manner, but no significant enhancement of the actions of procainamide were observed under exposure to any components of ischemia. Mechanisms underlying the difference of the depressant actions on ischemic myocardium between lidocaine and procainamide were discussed in the light of recent concepts of actions of local anesthetics, and came to the conclusion that lidocaine is the most preferable antiarrhythmic agent for the management of ventricular arrhythmias during acute ischemia or infarction.

Action Potentials↗
PubMed1983

Effects of hypoxia on conduction velocity of ventricular muscle.

The effects of hypoxia on the conduction of excitation in ventricular muscle were examined. Transmembrane action potentials and isometric tension of isolated rabbit papillary muscle were monitored simultaneously. When the preparations were exposed to hypoxia, the action potential duration (APD) shortened progressively and conduction velocity, assessed by the interval between two action potentials, decreased appreciably. This conduction delay was always accompanied by an increase in resting tension (RT). The upstroke velocity of the action potentials, however, was virtually unaffected by 60 min of hypoxia. When the perfusate was reoxygenated, the APD, conduction velocity and RT recovered. The conduction delay and elevation of RT due to hypoxia were prevented by verapamil or a low [Ca]0 medium and were potentiated by isoproterenol. These results suggest that a cytoplasmic Ca++ accumulation, resulting in intercellular electrical uncoupling, may contribute to the conduction delay during hypoxia.

Action Potentials↗
PubMed1983

Absorption and excretion of suprofen in both sexes of rats, guinea pigs, and rabbits.

DL-2-(4-2-Thienylcarbonyl)phenyl)propionic acid (suprofen) was rapidly absorbed in both sexes of rats, guinea pigs, and rabbits after oral administration. Blood levels after a single dose of 2 mg/kg 3H-suprofen in all the animals reached maxima within 15 min, and elimination of the 3H from blood was rapid; the radioactivity was mostly excreted in the urine and feces within 24 h after dosing.

Administration, Oral↗
PubMed1982

S-100 protein in human glial tumours. Qualitative and quantitative studies.

The authors studied a total of 48 human glial tumours for S-100 protein, an extremely acidic, protein specific to the nervous system, by immunohistochemistry and by micro-complement fixation assay in order to evaluate S-100 protein as an index for malignancy of glial tumours. All of 48 glial tumours analyzed in the present study demonstrated variable amounts of S-100 protein which might serve as a biochemical cell marker for glial tumours. The mean value of S-100 protein content in 3 ependymomas is higher than those of 19 low-grade (grades I, II) astrocytomas and 26 high-grade (grades III, IV) astrocytomas, being lowest in the latter. A statistically significant (P less than 0.001) difference in S-100 protein levels between low- and high-grade astrocytomas is observed, but not for ependymoma. At present, however, no correlation can be found between S-100 protein content of a tumor and the patient's survival time. Immunoperoxidase staining for S-100 protein in high-grade astrocytomas is generally weak in intensity and heterogeneous throughout the section, whereas that in low-grade astrocytomas and ependymomas is relatively strong and homogeneous, indicating that high-grade astrocytomas consist of a more heterogeneous population of tumour cells in terms of S-100 protein. These results show that the investigation of S-100 protein in a glial tumor is valuable to a certain extent in assessing the degree of differentiation or malignancy of the tumour.

Adolescent↗
PubMed1982

Properties of T antigen-positive phenotypic revertants isolated from SV40-transformed rat and mouse cells.

Four T antigen-positive phenotypic revertants were isolated by negative selection with BUdR from SV40-transformed rat and mouse cells which contain six and two viral genome equivalents per cell, respectively. Karyological analysis indicated that one rat and one mouse revertant had a hyperploid number of chromosomes, while the remaining two rat revertants had a subtetraploid number similar to those of the transformed parent cells. The hyperploid revertants were unable to grow in soft agar medium and were nontumorigenic in nude mice. One of the subtetraploid revertants formed large colonies at a very low frequency and induced tumors after a prolonged incubation period. These results indicate that there is a good correlation between the capacity of cells to grow without anchorage and the capacity to form tumors in nude mice and suggest that the revertant phenotype is stable in the presence of T antigen when the number of chromosomes is greatly increased as compared with that of the transformed parent cells.

Animals↗
PubMed1981

Studies on drug metabolism by use of isotopes XXVI: Determination of urinary metabolites of rutin in humans.

Determination of urinary metabolites of orally administered rutin and rutin-2',5',6'-d3 in humans was carried out by TLC and GLC-mass spectrometry. In human urine, 3-hydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxytoluene, and beta-m-hydroxyphenylhydracrylic acid were identified as rutin metabolites. Unchanged rutin and quercetin were not present in urine.

Biotransformation↗
PubMed1981

Evaluation of the drug-induced morphological differentiation of rat glioma cells (C-6) from the aspects of S-100 protein level and con A binding pattern.

The intracellular content of the nervous system specific protein S-100 began to increase with 4 days latency following the morphological differentiation of cultured rat glioma cells (C-6) with 1 mM dibutyryl cyclic AMP (dbcAMP), rising to approximately 10-fold over the control level at 15 days after the treatment. The concanavalin A (Con A) binding pattern on the external cell surface of C-6 cells exposed to dbcAMP appeared as a smooth layer of 40-60 nm thickness whereas that of control cells was irregularly thick and patchy. The correlation between morphological and biochemical changes of C-6 cells after dbcAMP treatment is discussed in relation to the mechanism controlling the differentiation of glioma cells.

Animals↗