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Biomedical subjects

N Nishimura

Publications and source records attributed to N Nishimura.

At least 235 records · Page 13Linked to original sources
PubMed1985

The effects of pantethine on lipid and lipoprotein abnormalities in survivors of cerebral infarction.

A daily 1000 mg of pantethine was orally administered to 12 male survivors of cerebral infarction for 3 months. Before and after the medication, plasma lipoproteins were ultracentrifugally separated. Plasma concentrations of total cholesterol, triglyceride, phospholipid, and VLDL- and LDL-cholesterol tended to decrease. On the contrary, HDL-cholesterol concentration and HDL:LDL-cholesterol ratio significantly increased. HDL2-cholesterol concentration significantly increased, whereas HDL3-cholesterol concentration remained unchanged, resulting in a significant elevation of HDL2:HDL3-cholesterol ratio. In HDL2 the percentage content of cholesterol and triglyceride decreased, while that of phospholipid increased. However, no significant changes were found in the chemical composition of HDL3. The plasma concentrations of apo A-I and, to a lesser extent, A-II increased, with a slight increase in A-I:A-II ratio but A-I:A-II ratio in either HDL2 or HDL3 remained unchanged.

Apolipoprotein A-I↗
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

Changes of hemodynamics and O2 transport associated with the perfluorochemical blood substitute, Fluosol-DA.

Hemodynamic, arterial O2 tension (PaO2) and transcutaneous O2 tension (PtcO2) changes associated with the infusion of 500 ml of Fluosol-DA were evaluated in 14 decerebrated patients. Flow-directed pulmonary artery catheters and the Clark-type oxygen electrode manufactured by Hoffmann-La Roche were utilized. The marked improvement of cardiovascular variables along with marked increases in PaO2 and PtcO2 may indicate a marked increase in skin circulation by the infusion of Fluosol. One patient exhibited a hypotensive episode during the infusion, which lasted only a short time, disappeared spontaneously, and did not prohibit the further infusion of Fluosol. We still consider that Fluosol will be clinically useful for increasing oxygen capacity and improving overall hemodynamic status as well as individual organ circulation.

Adult↗
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↗
PubMed1984

A new method for external fixation with single crystal alumina ceramic screw nail and its biomechanical study.

Through the use of the Hoffmann external fixator, we have recognized the importance of strength of fixation between the screw nail and the bone in the external fixation and have fully realized the necessity of an affinity of the screw nail to the soft tissue at the thrusting site of the screw nail. We made a screw nail for external fixation with single crystal alumina ceramic on an experimental basis and after its basic test of strength, tried its clinical application by the Hoffmann external fixator. When this screw nail was used, it was found difficult to fix the screw nails thrusted in each different direction by the Hoffmann external fixator because of the small elasticity of the sapphire screw nail itself. However when the screw nails were fixed by force, a great stress concentration occurred in them or the bone around them and this caused their breakage and loosening. To protect this, we have developed a new external fixator which enables to hold, connect and fix each screw nail at the individual thrusting positions and directions and is therefore completely universal to each plane.

Adult↗
PubMed1984

[Serial strain gauge measurement of bone healing in Hoffmann external fixation].

Since 1978, the author has applied Hoffmann external fixation to the treatment of open fractures and infected pseudoarthrosis of long bones in the lower limbs, but has some difficulties in determining when weight bearing should be started after operation, how much weight bearing should be and when the pin should be removed. As new method to mechanically analyze the callus strength, I tried to estimate the amount of strain at intervals of 2 to 3 weeks, beginning from the second week after operation, by bending or compressing the fracture site through the strain gauge glued to the middle of the external fixator's connecting rod. From a strength test by means of a model of fracture using a vinyl chloride pipe and also from a study of computer calculation using the model of plane beam structure for architectural design, it was found that the amount of the strain on the connecting rod decreased hyperbolically when the mechanical properties of the callus increased, and that it became constant when the mechanical properties of the callus reached 50% of the intact bone. The strength test using an cadaveric skin bone demonstrated that the callus volume was one of the most important and affecting factor. Twenty-three cases were treated by Hoffmann external fixation, and the bone healing was achieved in 20 of them. On the basis of the bone healing curve obtained by the serial strain gauge measurement in those cases, the bone healing process could be classified into 5 types: normal healing, slow healing, non-union, arrest in evolution and breakage of callus; and were employed as indexes in the post-operative rehabilitation program.

Adolescent↗
PubMed1983

Immunoreactive thyroid stimulating hormone (TSH)(: association with synaptosomally-rich fractions in the rat hypothalamus.

The subcellular compartmentalization of brain thyroid stimulating hormone (TSH) in the hypothalamus of the rat was investigated using differential and discontinuous sucrose density gradient centrifugation. When the mitochondrial fraction (P2) was layered on a discontinuous sucrose density gradient (0.32-1.4 M) and centrifuged for 60 min at 72,000 g, TSH recovered from the gradient was found, by double antibody radioimmunoassay, to be associated preferentially with the synaptosomally-rich layers. The separation was monitored by electron microscopic examination of all fractions obtained throughout the procedure. The addition of a large excess of either [125I]-labeled or unlabeled pituitary TSH at the time of homogenization did not influence the amount of immunoreactive TSH associated with the synaptosome-rich fractions, and both the unlabeled and labeled hormone were recoverable in the final supernatant indicating that the simple addition of peptide to hypothalamic homogenates did not result in any preferential association to any particular subcellular fraction. The apparent association of this brain-based pituitary peptide was not, therefore, an artifact of the homogenization process. It is concluded that an association exists between immunoassayable TSH and brain-based synaptosomes in homogenates of the rodent hypothalamus.

Animals↗