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Biomedical subjects

F Yoshida

Publications and source records attributed to F Yoshida.

At least 91 records · Page 5Linked to original sources
PubMed1987

Carbon dioxide reactivity of cerebral cortical and pial arteries in spontaneously hypertensive and normotensive rats--a morphometric study.

The responsiveness of cerebral arteries to the changes in arterial carbon dioxide tension (paCO2) was studied in spontaneously hypertensive rats (SHRs) and normotensive rats (NTRs). A freeze substitution method was applied for the preparation of pial and cortical arteries for morphometrical study. Hypercapnia was induced by giving 8% CO2, and hypocapnia was provided by hyperventilation. The ratios of internal (d) to external diameter (D) (d/D ratio) of both pial and cortical arteries in SHR were not different from those in NTRs during normocapnia. In hypercapnia, the ratios of pial and larger cortical arteries (D greater than or equal to 20 micron) in SHRs were 80.9 +/- 0.8% and 78.6 +/- 0.6%, respectively, being significantly smaller than 86.2 +/- 0.7% and 82.2 +/- 0.5% in NTR. In contrast, the d/D ratio of pial arteries in hypocapnia was 72.5 +/- 1.4% in SHRs, which was significantly larger than 67.5 +/- 1.4% in NTRs. The responsiveness of smaller cortical arteries (D less than 20 micron) to paCO2 was not different between SHRs and NTRs. The present results suggest that in SHRs cerebrovascular CO2 reactivity is decreased as compared to NTRs, especially in pial and larger cortical arteries.

Animals↗
PubMed1987

[Physiological and self-rated affective/cognitive responses of the neurotic personality to an interpersonal stress situation].

The effects of approach by an unacquainted male to high- or low-neurotic (on the MPI scale) female subjects on physiological responses (heart rates and eye blinks) and self-rated affective/cognitive responses (tension, anxiety and apparent size of the male) were examined. (a) In the first trial, non-neurotic subjects showed an abrupt increase of HR near the personal space boundary, however showed a rapid habituation at the second and third trials. In contrast, self-rated affection (tension and anxiety) increased gradually as the male approached, and habituation was slow at the later trials. (b) Neurotic subjects displayed higher tension than non-neurotic subjects, while tension, anxiety and heart rate were less habituating. (c) INDSCAL analysis revealed that these three self-rated indices clustered together, while the physiological ones did not. (d) It was suggested that the eye blink response had a tension reducing function.

Adolescent↗
PubMed1986

Mechanical effects on rates of hemolysis.

Empirical studies were conducted on how rates of hemolysis were influenced by mechanical factors, such as shear, turbulence, agitation, pressure fluctuation, and bubbling, in five types of experimental apparatus: rotating cylinder, rotating disks, agitated vessel, pressure pulsator, and bubble columns. Our data indicate, at least qualitatively, that an important mechanical factor controlling rates of hemolysis in practical devices, in which blood does not flow in thin channels or capillaries, is the turbulent stress in the bulk blood, rather than the shear at the blood-solid interface.

Hemolysis↗
PubMed1986

Newly developed circulating blood volume-monitoring system and its clinical application for measuring changes in blood volume during hemofiltration.

Blood and ultrafiltrate electrical resistivities were continuously monitored during hemofiltration. By substituting these values into a previously developed equation that was modified by the authors, the hematocrit value was determined; and blood volume change was obtained from the change in this value. The following facts were discovered as the result of monitoring the blood volume change during treatment: When the body position was changed from the reclining to the sitting position, the blood volume decreased by 4.2 +/- 0.3%. With the body water removal rate kept constant, the body position recumbent, and the subject fasted, the blood volume gradually decreased. However, when the position was changed from reclining to sitting for food intake and once more returned to the supine position after the meal, the blood volume was greatly affected by the change in position and the food intake.

Blood↗
PubMed1986

Effects of intravenous glycerol on cerebral blood flow and tissue metabolism in acute cerebral ischemia in spontaneously hypertensive rats.

The effects of antiedematous agent with intravenous 10% glycerol on cerebral blood flow (CBF) and metabolism were studied in acute cerebral ischemia experimentally induced by bilateral carotid artery occlusion in spontaneously hypertensive rats (SHR). CBF was measured by the hydrogen clearance technique and brain tissue metabolites such as lactate, pyruvate and ATP in the ischemic brain frozen in situ were determined by the enzymatic method. In comparison with saline-infused SHR, the reduction of CBF in the thalamus following carotid occlusion was significantly small in the glycerol treated SHR. Supratentorial ATP concentration in the 3 hr-ischemic brain was reduced in both groups of rats, but its reduction was significantly smaller in the glycerol-infused group than the other. Lactate and lactate/pyruvate ratio tended to be less increased in the glycerol rats, indicating that ischemic metabolism was restrained by the treatment. The present results strongly suggest that intravenous glycerol is effective against acute cerebral ischemia from the view point of cerebral hemodynamic and metabolism.

Acute Disease↗