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Biomedical subjects

N Nishimura

Publications and source records attributed to N Nishimura.

At least 109 records · Page 6Linked to original sources
PubMed1984

Cardiovascular changes in the terminal stage of disease.

In 11 patients with brain death, we measured cardiovascular parameters until cardiac arrest. After withdrawal of vasopressors, we observed marked falls in the cardiac output, systemic vascular resistance, heart rate and arterial pressure. In consequence, there was a marked decrease in oxygen delivery and the fall in arterial pressure established a vicious circle and circulatory death ensued. Most pronounced changes were left heart dysfunction and a fall in systemic vascular resistance. On the other hand, depression of the right side of the heart was half of that of left side, and the pulmonary circulation and volume status were well maintained until death. At the same time we found in these patients that body temperature and organ function except that of the brain were well maintained in brain dead patients. For resuscitation of apparently dead patients one must maintain not only cardiac functions but also systemic vascular functions.

Adult↗
PubMed1984

Circulatory support with sympathetic amines in brain death.

In 12 cases of brain death, the cardiovascular effects and changes of transcutaneous PO2 (PtcO2) during infusion of various sympathomimetic amines were determined. The larger amounts of vasopressors were necessary to maintain the blood pressure at more than 100 mmHg. With norepinephrine and dopamine, marked increase in blood pressure, cardiac output, systemic vascular resistance and also PtcO2 were observed. On the other hand, dobutamine was not an effective pressor agent in those situations. Even with more than 10 times the routinely used concentration of dobutamine, difficulties were encountered in keeping the blood pressure above 100 mmHg in many cases studied. With the infusion of dobutamine, a marked increase in cardiac output and heart rate were observed with a decrease in systemic vascular resistance and a fall in PtcO2 values in many occasions. In brain death, norepinephrine and dopamine will be recommended as the pressor agents in clinical practice. The changes of PtcO2 closely followed the changes of arterial blood pressure and did not parallel the changes of cardiac output or of heart rate.

Adult↗
PubMed1984

Metaraminol and dobutamine for the treatment of hypotension associated with epidural block.

In 14 patients undergoing major abdominal surgery, epidural analgesia was performed and cardiovascular changes were examined by insertion of Swan-Ganz catheters. To counteract the hypotensive episodes associated with epidural block, Dobutamine (1-3 micrograms/kg body wt min-1) and Metaraminol (0.5-1.5 micrograms/kg body wt min-1) in various doses were infused and the effects of these vasoactive agents were examined. Epidural analgesia decreased arterial pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure and central venous pressure associated with marked decrease in cardiac index, stroke volume index, left ventricular and right ventricular stroke work without changes in systematic vascular resistance, pulmonary vascular resistance or heart rate. The infusion of Metaraminol caused a marked increase in arterial pressure, pulmonary arterial pressure, wedge pressure and central venous pressure. Calculated variables of stroke volume, systemic vascular resistance, left and right stroke work and cardiac work increased significantly. The infusion of Dobutamine caused a marked increase in arterial and pulmonary arterial pressure, wedge pressure, central venous pressure and cardiac index associated with those calculated changes of left and right stroke work and cardiac work, which were increased markedly. On the other hand, heart rate, stroke volume and pulmonary vascular resistance did not show any remarkable changes. Our study indicates that the fall in arterial blood pressure associated with epidural block may be due to marked decrease in cardiac output, and the infusion of Dobutamine is one of the desirable methods to counteract the hypotensive episode.

Adult↗
PubMed1984

Oxygen conformers in critically ill patients.

In 104 patients with various pathological conditions, the correlation between oxygen consumption and oxygen delivery was analysed by the least square method. As reported by Peirce in 1977, we also found oxygen conformers among critically ill patients, but a tendency to oxygen regulator was never found in our patients.

Adolescent↗
PubMed1984

Aspartase-hyperproducing mutants of Escherichia coli B.

When a wild-type strain of Escherichia coli B was cultured on a medium containing L-aspartic acid as the sole carbon source (Asp-C medium), aspartase formation was higher than that observed in minimal medium. Addition of glucose to Asp-C medium decreased aspartase formation. When also cultured in a medium containing L-aspartic acid as the sole nitrogen source (Asp-N medium), E. coli B showed a low level of aspartase formation and an elongated doubling time. To obtain aspartase-hyperproducing strains, we enriched cells growing faster than cells of the wild-type strain in Asp-N medium by continuous cultivation of mutagenized cells. After plate selection, the doubling times of these mutants were measured. Thereafter, fast-growing mutants were tested for aspartase formation. One of these mutants, strain EAPc7, had a higher level of aspartase formation than did the wild-type strain in medium containing L-aspartic acid as the carbon source, however; addition of glucose to this medium decreased aspartase formation. The other mutant, strain EAPc244, had a higher level of aspartase activity than did the wild-type strain in both media. Therefore, aspartase formation in mutant EAPc244 was released from catabolite repression. In strain EAPc244 the other catabolite-repressible enzymes, beta-galactosidase, tryptophanase, and the three tricarboxylic acid cycle enzymes, were also released from catabolite repression. Both mutants had sevenfold the aspartase formation of the wild-type strain in a medium which contained fumaric acid as the main carbon source and which has been used for industrial production of E. coli B aspartase. However, strain EAPc244 had 2.5-fold the fumarase activity of strain EAPc7.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonia-Lyases↗
PubMed1983

Changes of lung water and cardiovascular parameters during neurosurgical procedures associated with various types of infusion.

With the Swan-Ganz catheter and double indicator technique cardiovascular parameters and lung water were measured in 16 neurosurgical procedures. Five hundred millilitres of whole blood, Manitol or Fluosol-DA, or 1000 ml of lactate-Ringer solution was infused within 30 min, and various parameters were estimated and analysed. Extravascular lung water did not change with either solutions. Fluosol-DA showed the most powerful pressure effects. With whole blood and Fluosol DA, cardiac output and oxygen availability increased. Marked hemodilution was observed with the infusion of either Manitol, Fluosol-DA or lactate-Ringer solution, but only Fluosol-DA insured adequate oxygen supply to tissues by increase in oxygen capacity in blood. Fluosol-DA proved to be one of the suitable colloidal solutions to improve the hemodynamics and hemodilution during operation.

Adult↗
PubMed1983

Zearalenone reductase from rat liver.

Zearalenone is known to be reduced by rat liver preparations to a more active estrogenic metabolite, alpha-zearalenol. To elucidate the enzymatic feature of zearalenone reductase, we worked out a simple assay procedure for this enzyme using [3H]-zearalenone and thin layer chromatography (TLC). The NAD(P)H-dependent zearalenone reductase localized in the microsomes was most active at pH 4-4.5, while the reductase localized in the cytosol was active at neutral pH. The former enzyme reduced zearalenone only to alpha-zearalenol and the latter reduced both alpha-zearalenol and beta-zearalenol. The microsomal enzyme was solubilized with Triton X-100 and purified by DEAE-Sephadex, hydroxyapatite and Sepharose 4B column chromatographies. The partially purified enzyme showed the following properties. a) The molecular weight of the enzyme was estimated to be about 230,000 by Sepharose 4B chromatography. b) The apparent Km value of the enzyme was 1.0 X 10(-5) M for zearalenone at an NADPH concentration of 1 mM. c) The enzyme activity was inhibited by a high concentration of KCl but not by 1 mM Co2+, Mn2+, Zn2+, EDTA, or 20 mM N-ethylmaleimide.

Alcohol Oxidoreductases↗
PubMed1983

Cardiovascular effects of various colloidal solutions during major abdominal surgery.

We examined the effects of various colloidal solutions on cardiovascular and oxygen transport variables for 26 patients undergoing gastrectomy under general anesthesia. Fluosol-DA, whole blood, 3% Dextran-40 (Saviosol), and 6% hydroxyethyl starch (hetastarch, Hespan) affected the right side of heart, but only whole blood and Fluosol-DA significantly increased cardiac output and oxygen delivery (DO2). Fluosol-DA may prove useful for critical care of hemorrhagic shock during operation or resuscitation in the immediate postoperative period.

Adult↗
PubMed1983

Alterations of gastrin secretion in obese rats with ventromedial hypothalamic lesions.

Basal plasma gastrin levels were significantly higher in obese rats induced by ventromedial hypothalamic lesions (VMH rats) than in sham-operated controls. Gastrin secretion in response to insulin hypoglycemia and a liquid diet load was higher in VMH rats than in controls. The antral gastrin concentration was also elevated in VMH rats. Pair-fed rats with VMH lesions showed increased gastrin secretion as did the non-pair-fed group. These results show that gastrointestinal hormone secretions as well as pancreatic endocrine function are abnormal in obese rats with VMH lesions. Increased gastrin secretion is probably induced by factors other then hyperphagia, such as disturbance of the autonomic nervous system due to the VMH lesions.

Animals↗