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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 811 records · Page 45Linked to original sources
PubMed1986

N-hydroxy-2-acetylaminofluorene as effective inhibitor of aldehyde oxidase.

N-Hydroxy-2-acetylaminofluorene has been found to be an effective inhibitor of aldehyde oxidase. At concentrations of 1 X 10(-6) M and 1 X 10(-5) M, 38% and 88% inhibition was observed on the oxidase activity towards N1-methylnicotinamide. The inhibition was of noncompetitive type and had a Ki value of 4.4 X 10(-6) M. In contrast, little inhibition of the enzyme was observed with 2-aminofluorene, 2-acetylaminofluorene and acetohydroxamic acid even at a concentration of 1 X 10(-4) M.

2-Acetylaminofluorene↗
PubMed1986

An HRP study of the motoneurons supplying the rat hypobranchial muscles: central localization, peripheral axon course and soma size.

The locations of motoneurons (MNs) supplying the rat hypobranchial muscles (lingual, geniohyoid, and infrahyoid) and the peripheral courses of axons of these MNs were investigated by using a method of HRP injection into the hypoglossal nerve or these muscles in combination with severing of the hypoglossal and/or cervical components of the plexus hypoglossocervicalis. Moreover, some sizes of the MNs were investigated in both transverse and horizontal sections. The hypobranchial MNs formed a sequence of cell columns extending caudally from the hypoglossal nucleus, via the supraspinal nucleus, to the medial and then the ventrolateral subnuclei of the ventral horn of C1 to C3. The lingual and geniohyoid MNs were located in the hypoglossal nucleus. The majority of their axons passed solely through the hypoglossal nerve, whereas a small number of axons, whose somata lay in the caudal hypoglossal nucleus, passed through the first cervical nerve and then through the ansa cervicalis to reach the hypoglossal nerve. The infrahyoid MNs were located in the supraspinal nucleus and the ventral horn, and their axons passed through the first to third cervical nerves. The hypobranchial MNs were divided into three groups according to their size: the lingual, the geniohyoid and thyrohyoid, and lastly the other infrahyoid MNs, in order of smaller to larger size. The sizes of lingual, geniohyoid, and thyrohyoid MNs displayed a unimodal distribution both in transverse and horizontal sections, whereas the other infrahyoid MNs showed a bimodal distribution.

Animals↗
PubMed1986

Structural and functional integrity of rat liver perfused in backward and forward directions.

The purpose of this study was to assess if reversal of the direction of isolated rat liver perfusion would cause significant alterations in hepatic functions and structure. Five isolated rat livers were perfused forward and another five backward with oxygenated Ringer's solution for up to 90 min (hydrostatic pressure: less than or equal to 13 cm H2O; flow rate: forward 3.88 +/- 0.34 ml/min per gram and backward 3.76 +/- 0.34 ml/min per gram). At the end of the experiment, livers were perfusion-fixed for morphological examination. The following results were obtained: No significant differences were noted between the forward and backward perfusions with respect to oxygen uptake, mean bile flow (forward 0.57 +/- 0.12; backward 0.60 +/- 0.14 ml/min per gram), average bile acid excretion (forward 2.39 +/- 1.11; backward 2.83 +/- 0.94 nmol/min per gram), hydroxylation pattern of bile acids, urea synthesis, release of lactic dehydrogenase, glucose secretion, and redox ratios. Light and electron microscopy, including morphometry of parenchymal and sinusoidal areas, revealed that the backward perfusion caused a greater degree of sinusoidal distension, but no other noteworthy differences. Hepatic ultrastructure was well preserved. We conclude that reversing the direction of perfusion does not alter structure and major hepatic functions significantly.

Animals↗
PubMed1986

Effect of thromboxane synthetase inhibitors (OKY-046, OKY-1580) on experimentally induced air embolism in anesthetized dogs.

We investigated the effects of OKY-046 and OKY-1580, thromboxane A2 (TxA2) synthetase inhibitors, on plasma levels of 6-keto PGF1 alpha and TxB2 in anesthetized dogs with experimentally induced air embolism. The percentage increase of tracheal pressure induced by room air infusion was suppressed significantly by premedication with OKY-046. The percentage increase of pulmonary artery blood pressure was suppressed significantly by premedication with OKY-046 compared to that in control group. By room air infusion after the premedication with OKY-046 and OKY-1580, systemic artery blood pressure did not show any significant changes. Plasma 6-keto PGF1 alpha level showed a marked increase by an intravenous infusion of room air, and such an increase became more predominant by the premedication with OKY-046 and OKY-1580. On the other hand, plasma TxB2 level showed a marked increase by an intravenous infusion of room air, and such an increase became less predominant by the premedication with OKY-046 and OKY-1580. These results may suggest that OKY-046 and OKY-1580 are not only TxA2 synthetase inhibitors but also PGI2 synthetase accelerators and are useful drugs for treatment and prevention of thromboembolism.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Coronary sinus blood flow and myocardial oxygen consumption after valve replacement for aortic insufficiency.

Seven cases are reviewed in which the aortic valve was replaced with a Björk-Shiley tilting disk valve to treat aortic insufficiency. Comparative studies were made to determine coronary sinus blood flow (CSF) and myocardial oxygen consumption (MVO2) by using a continuous thermodilution method both before and after the operation. Additionally, indexes of left ventricular function were obtained by catheterization of the right and left heart and by left ventriculography. Postoperative total CSF decreased significantly compared with the preoperative value (p less than 0.02). However, in all cases, the postoperative CSF per 100 g of left ventricle (LV) increased compared with the preoperative measurement (p less than 0.001). The CSF per beat per 100 g LV also increased postoperatively (p less than 0.001). Total MVO2 decreased postoperatively (p less than 0.02). However, the MVO2 per unit mass tended to increase postoperatively; these increases were not significant. Postoperatively the left ventricular mass and left ventricular wall stress decreased considerably. The left ventricular ejection fraction (EF) and the mean velocity of circumferential fiber shortening (mVCF) remained at normal levels, whereas the left ventricular function improved markedly. In short, the total CSF decreased, along with LVM and left ventricular wall stress. However, because CSF per unit mass increased and EF and mVCF remained at normal values, it is assumed that the increase in CSF is associated with improvement in postoperative contractility.

Adult↗
PubMed1986

Intravascular bronchiolo-alveolar tumor (IVBAT). Case report with the immunological analysis.

A case of intravascular bronchiolo-alveolar tumor, a rare lung neoplasm which is often found among women, is reported. Our ultrastructural findings and existence of factor VIII-related antigen support the hypothesis of vascular origin. The relationship between IVBAT and epithelioid hemangioendothelioma is discussed. We also examined whether immunological abnormalities existed in our patient, because tuberculin test gave negative result in many cases reported previously and our case. No specific immunological change was found except for negative tuberculin test.

Adult↗
PubMed1986

Studies on lipoxygenase inhibitors. II. KF8940 (2-n-heptyl-4-hydroxyquinoline-N-oxide), a potent and selective inhibitor of 5-lipoxygenase, produced by Pseudomonas methanica.

Pseudomonas methanica KY4634 was found to produce 5-lipoxygenase inhibitor designated KF8940, MY12-62a and MY12-62c. The inhibitors were purified by solvent extraction, silica gel column chromatography, reversed-phase low pressure liquid chromatography and crystallization. The chemical structures of KF8940, MY12-62a and MY12-62c were determined to be 2-n-heptyl-4-hydroxyquinoline-N-oxide, 2-n-heptyl-4-hydroxyquinoline and 3-n-heptyl-3-hydroxy-1,2,3,4-tetrahydroquinoline-2,4-dione, respectively, on the basis of their physico-chemical properties. Among them, KF8940 was the most potent inhibitor. The compound inhibited 5-lipoxygenase of rat basophilic leukemia cells in a dose-dependent manner and the half maximal inhibitory concentration (IC50) was 1.5 X 10(-7) M. At this concentration, KF8940 did not inhibit bovine platelet 12-lipoxygenase and cyclooxygenase, and the IC50 values for these enzyme were 3.5 X 10(-5) M and 1.7 X 10(-4) M, respectively. The results indicated that KF8940 is a potent and selective inhibitor of 5-lipoxygenase. The IC50 value of MY12-62c for 5-lipoxygenase was 1.9 X 10(-5) M and that of MY12-62a was 1.9 X 10(-5) M.

Arachidonate Lipoxygenases↗
PubMed1986

Studies on lipoxygenase inhibitors. I. MY3-469 (3-methoxytropolone), a potent and selective inhibitor of 12-lipoxygenase, produced by Streptoverticillium hadanonense KY11449.

Streptoverticillium hadanonense KY11449 was found to produce a 12-lipoxygenase inhibitor MY3-469. The compound was purified by chromatography on Diaion HP-10, charcoal, Sephadex LH-20 and crystallization. The chemical structure of MY3-469 was determined to be 3-methoxytropolone on the basis of its physico-chemical properties. The half maximal inhibitory concentration (IC50) of MY3-469 against bovine platelet 12-lipoxygenase was 1.8 X 10(-6)M. The compound did not inhibit bovine platelet cyclooxygenase at 10(-3)M and showed weak inhibition (IC50 2.8 X 10(-4)) against 5-lipoxygenase of rat basophilic leukemia cells. The results indicate that MY3-469 is a potent and selective inhibitor of 12-lipoxygenase.

Actinomycetales↗
PubMed1986

[Evaluation of left ventricular function and coronary sinus blood flow during exercise after aortocoronary bypass surgery. Influence of revascularization of the left anterior descending artery].

Left ventricular function and coronary sinus blood flow at rest and during exercise were evaluated in 27 patients after aortocoronary bypass surgery and in 13 normal subjects (G-C). Twenty patients (G-1) had successfully revascularized left anterior descending artery (LAD). In 7 patients (G-2), the revascularization for LAD was not complete. There was no difference among 3 groups in stroke work index (SWI), left ventricular end-diastolic pressure (LVEDP) and coronary sinus blood flow (CSF) at rest. SWI during exercise in G-2 (44.7 +/- 14.7 g. M/beat/m2) was significantly lower than that in G-1 and G-C (67.9 +/- 15.0, 77.2 +/- 17.0 g.M/beat/m2) (p less than 0.02, p less than 0.002). LVEDP during exercise in G-2 (32 +/- 6 mmHg) was significantly higher than that in G-1, G-C (17 +/- 7, 13 +/- 3 mmHg) (p less than 0.001, p less than 0.001). CSF during exercise in G-2 (160 +/- 64 ml/min) was significantly lower than that in G-1, G-C (357 +/- 79, 290 +/- 113 ml/min) (p less than 0.001, p less than 0.002). These data indicated that left ventricular function during exercise and coronary sinus blood flow reserve for exercise in patient with completely revascularized LAD was significantly better than that in patients with incompletely revascularized LAD.

Adolescent↗