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Biomedical subjects

K Yoshimura

Publications and source records attributed to K Yoshimura.

At least 127 records · Page 7Linked to original sources
PubMed1988

Dibutyryl cyclic AMP inhibits acute hypoxic pulmonary vasoconstriction in conscious sheep.

We examined the effects of cell-permeable dibutyryl cyclic AMP (DBcAMP) on acute hypoxic pulmonary vasoconstriction (HPV) in conscious sheep. Mean left and right atrial, pulmonary, and systemic pressures (Pla, Pra, Ppa, and Psa, mm Hg), cardiac output (CO, L/min), and heart rate were measured continuously. Systemic (SVR) and pulmonary vascular resistances (PVR) were calculated by (Psa-Pra)/CO and (Ppa-Pla)/CO, respectively. Five groups of experiments were performed using the same sheep (n = 6). After a 30-min baseline period, sheep inhaled a hypoxic gas mixture (O2:N2 = 1:9) for 40 min. Pretreatment with DBcAMP (200 micrograms/kg/min) inhibited HPV (Ppa, 12.0 +/- 2.3 to 20.0 +/- 2.3 versus 13.2 +/- 2.5 to 14.3 +/- 1.4 mm Hg, p less than 0.01; PVR, 2.61 +/- 0.81 to 4.15 +/- 1.14 versus 2.30 +/- 0.87 to 2.52 +/- 0.59 mm Hg/L/min, p less than 0.01). DBcAMP treatment (200 micrograms/kg/min) after induction of HPV also significantly attenuated hypoxic pulmonary response (Ppa, 19.0 +/- 1.7 to 14.2 +/- 2.3 mm Hg, p less than 0.01; PVR, 3.92 +/- 0.39 to 2.34 +/- 0.34 mm Hg/L/min, p less than 0.01) without significant decreases in Psa and SVR. Pretreatment with DBcAMP (200 micrograms/kg/min) did not significantly alter pulmonary pressor responses to bolus injections of prostaglandin F2 alpha (PGF2 alpha) (10 micrograms/kg) and norepinephrine (4 micrograms/kg). These results may suggest that intracellular augmentation of cyclic AMP plays a crucial role in modulating HPV.

Acute Disease↗
PubMed1988

Thromboxane synthetase inhibition and pulmonary response to hypoxia in conscious adult sheep.

This study investigated the effects of a thromboxane synthetase inhibitor (OKY-046) and a cyclooxygenase inhibitor (ketoprofen) on hypoxic pulmonary vasoconstriction in conscious adult sheep in order to evaluate the physiological role of thromboxane and other cyclooxygenase products. In addition, we studied the effects of histamine H1 (chlorpheniramine) and H2 antagonists (cimetidine) on hypoxic pulmonary vascular tone. Hypoxia caused a 37% rise in pulmonary arterial pressure (p less than 0.05) and a 36% increase in pulmonary vascular resistance (p less than 0.05). Pretreatment with intravenous OKY-046 10 mg/kg or ketoprofen 2 mg/kg had no effect on normoxic pulmonary vascular tone and inhibited the increase in plasma TXB2 concentration during hypoxia without affecting the pulmonary pressor response to hypoxia. Cimetidine produced an increase in hypoxic pulmonary vascular tone when individual members of the group were compared, but there was no statistically significant difference when the group was compared to the control study. Chlorpheniramine had no effect on hypoxic pulmonary tone. These data suggest that hypoxic pulmonary vasoconstriction is not mediated by release of TXA2, that hypoxic vascular tone is not modulated by cyclooxygenase products, and that the histamine H2 receptor may play a modulating role in hypoxic pulmonary vasoconstriction in conscious adult sheep.

Acrylates↗
PubMed1988

[Effects of flutropium bromide, a new antiasthma drug, on mediator release from mast cells and actions of mediators].

The effects of flutropium bromide (Ba598Br), a new antiasthma drug possessing the quarternary ammonium structure of atropine derivatives, on mediator release from mast cells and on actions of leukotriene (LT) D4 and serotonin were investigated. Flutropium bromide (3 and 10 mg/kg, i.v.) showed an inhibitory action on the 48 hr homologous PCA in guinea pigs. Atropine showed no inhibitory effect. Flutropium bromide also inhibited the release of histamine from isolated rat mast cells stimulated by antigen, although the inhibitory action was weaker than that of disodium cromoglycate. Atropine also had no inhibitory action in this case. Flutropium bromide and atropine showed no antagonistic action against LTD4-induced contraction of isolated tracheal smooth muscle of guinea pigs. Inhalation of flutropium bromide (0.3%) also showed no antagonistic action against serotonin-induced bronchoconstriction in dogs. From the above results, it is indicated that flutropium bromide has a weak mast cell stabilizing action, but no antagonistic action against LTD4 and serotonin.

Animals↗
PubMed1988

Suppression of hepatic HMG-CoA reductase activity by beta-muricholic acid in mice fed a diet containing cholesterol and cholic acid.

A diet containing cholesterol and cholic acid (SID) is known to induce the formation of cholesterol fatty liver as well as cholesterol gallstones. The activity of HMG-CoA reductase, one of the key enzymes for cholesterol synthesis in the liver, is significantly lowered by addition of beta-muricholic acid to SID. The prevention of fatty liver formation by beta-muricholic acid was accompanied by the suppression of HMG-CoA reductase activity.

Animals↗
PubMed1988

The increased sympathoadrenal activity in patients with high altitude pulmonary edema is centrally mediated.

To assess the role of catecholamines in the pathogenesis of high altitude pulmonary edema (HAPE), 24-hour urinary catecholamine excretions and plasma catecholamine concentrations were measured. We also performed brain computed tomography (CT) in the same 8 serial patients with HAPE. 24-hour urinary norepinephrine excretion showed a statistically high value on admission compared with that after recovery (396.9 +/- 92.9 micrograms/24 hr, decreasing to 93.0 +/- 31.1 micrograms/24 hr, mean +/- S.E., p less than 0.01). 24-hour urinary epinephrine excretion on admission was also remarkably high, and returned later normal (62.9 +/- 25.8 micrograms/24 hr, decreasing to 12.7 +/- 4.2 micrograms/24 hr, p less than 0.05). Plasma norepinephrine concentration was also high, but returned to normal (0.260 +/- 0.073 ng/ml, to 0.11 +/- 0.043 ng/ml) by the time of discharge. Brain CT scans revealed diffuse low density of the entire cerebrum, small ventricles, disappearance of sulci, and small cistern, suggesting cerebral edema. These findings may suggest that the heightened sympathoadrenal activity that occurred in the patients concomitant with cerebral edema was related to the high altitude illness rather than to simple exposure to high altitude.

Adrenal Glands↗
PubMed1988

[A case of adenomatous polyps with prostatic type epithelium].

A 41-year-old male presented with gross hematuria and was found to have a polypoid lesion of the prostatic urethra. This proved to be an adenomatous polyp with prostatic type epithelium. Transurethral resection was performed on August 3, 1985. He had no evidence of recurrence following the operation. Previously reported cases of relevance are briefly discussed.

Adult↗
PubMed1988

[Nonpenetrating brachiocephalic arterial injury].

The injury of brachiocephalic artery is uncommon in the blunt trauma and sometimes it was accompanied by other organ damages. We reported a case and reviewed 47 cases in literature. A 28-year-old woman was transferred to our hospital with the blunt chest trauma and the cerebral infarction due to the traffic accident. The cineangiogram showed complete obstruction at the middle portion of brachiocephalic artery and the subclavian steal-carotid recovery phenomenon. Thirty days after trauma, the operation was performed under the monitoring of right superficial temporal arterial pressure. The vessel with intimal defect was plugged by a clot and it was replaced with a Gore-Tex graft during simple occlusion of the right carotid, subclavian and brachiocephalic arteries without any monitoring pressure change. The postoperative course was uneventful and the symptom improved. The review decided that the main cause of the injury is traffic accidents and the cineangiogram is important to find the arterial damage and the monitoring of superficial temporal arterial pressure is helpful to avoid the brain ischemia during operation.

Accidents, Traffic↗
PubMed1988

A case of high altitude pulmonary edema followed by brain computerized tomography and electroencephalogram.

A case of high altitude pulmonary edema with high altitude cerebral edema was reported. A young Japanese male complained of severe palpitation and shortness of breath on the third day of climbing at 3,000 m above sea level. During the next 2 d at altitude, the following symptoms occurred: cough with foamy sputum, cyanosis, and loss of consciousness. Soon after evacuation, he showed severe hypoxemia and deep coma with decerebrate rigidity; electroencephalogram showed diffuse alpha waves, indicating "alpha wave coma." Brain computerized tomography revealed brain edema, showing small compressed ventricles and diffuse low density of the cerebrum. Pulmonary edema on chest roentgenogram disappeared by the fifth hospital day, and his consciousness recovered gradually during the next 2 weeks after the admission. He was examined serially by electroencephalography and brain computerized tomography. He recovered fully, but there were transient psychological abnormalities soon after discharge and mild brain atrophy was observed by brain computerized tomography 6 years later.

Adult↗
PubMed1988

[A case of rupture of a posterior pancreaticoduodenal artery aneurysm].

A 75 year old man complaining of right upper abdominal pain was admitted to our hospital. He became shocked with hypotension and cold sweat, and immediately underwent operation. Laparotomy revealed massive hemorrhage in the retroperitoneal region, particularly in the right upper space. It was derived from the rupture of the posterior pancreaticoduodenal artery aneurysm. The arterial trunk was ligated above and below the aneurysm and the aneurysmectomy was carried out. The patient recovered and was discharged from the hospital 56 days after operation. There was no other visceral artery aneurysm and the etiology of this aneurysm was unknown. Four cases of pancreaticoduodenal artery aneurysm have been reported in Japan and three of them were operated, but this is the first surgically resected case for the rupture of pancreaticoduodenal artery aneurysm with success.

Aged↗
PubMed1987

Differences between Saccharomyces cerevisiae and Bacillus subtilis in secretion of human lysozyme.

Saccharomyces cerevisiae secreted human lysozyme in the medium as an active form when the signal peptides of chicken lysozyme and a chicken lysozyme-Aspergillus awamori glucoamylase hybrid were used, whereas it did not synthesize any human lysozyme protein by using the signal peptide of A. awamori glucoamylase. The secreted lysozyme was easily purified and crystallized. On the other hand, Bacillus subtilis secreted an inactive human lysozyme, which seemed to have incorrect disulfide bonds, with the signal peptide of amylase and its mutants. The free energy changes for the membrane translocation of the signal peptides are related to the secretion of human lysozyme in S. cerevisiae, but not in B. subtilis. These results indicate that differences exist between S. cerevisiae and B. subtilis in the secretion of human lysozyme.

Amino Acid Sequence↗
PubMed1987

Complete amino acid sequence of PO protein in bovine peripheral nerve myelin.

The P0 protein is a major structural glycoprotein of molecular weight 28,000 in peripheral nerve myelin. The complete amino acid sequence of bovine P0 protein was determined. The polypeptide chain consists of 219 amino acid residues and includes a highly hydrophobic domain (residues 125-150) in the middle, which probably represents a transmembrane segment. The amino terminal domain (residues 1-124) is relatively hydrophobic, but contains a negatively charged carbohydrate chain at Asn93. This domain is most likely located on the extracellular side of the membrane and may contribute to formation of the myelin intraperiod line by hydrophobic and electrostatic interactions. On the other hand, the basic carboxyl-terminal domain (residues 151-219) may protrude from the cytoplasmic side of the membrane and is probably involved together with basic proteins in the formation of the major myelin dense line through electrostatic interaction with acidic lipids in the membrane. The few interspecies amino acid variations between the bovine P0 and the rat P0 sequences, deduced from the cDNA (Lemke, G., and Axel, R. (1985) Cell 40, 501-508), indicate that the P0 protein is conserved across species.

Amino Acid Sequence↗
PubMed1987

Cerebral infarction due to systemic necrotizing vasculitis in a patient with rheumatic heart disease, subacute bacterial endocarditis and status epilepticus.

Systemic necrotizing vasculitis involving cerebral blood vessels is described in a 30-year-old man with rheumatic heart disease and subacute bacterial endocarditis. Fever, anaemia, splenomegaly and positive blood cultures for Gram-negative bacteria were found on admission. The fever resolved with antibiotic therapy on the third hospital day but he then developed hemiplegia and multifocal seizures. The seizures progressed to uncontrollable status epilepticus accompanied by congestive heart failure and the patient died 20 d after admission. At autopsy, exudative and necrotizing vasculitis involving medium- to small-sized arteries was seen in the brain, the heart and the skeletal muscles. Rheumatic myocarditis and endocarditis and old rheumatic mitral valve deformities were also present. In addition, verrucous endocarditis in the mitral valve and Löhlein's focal glomerulonephritis were noted. We discuss the possible mechanism of the systemic necrotizing vasculitis in relation to rheumatic fever.

Adult↗