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Biomedical subjects

Y Momota

Publications and source records attributed to Y Momota.

24 records · Page 2Linked to original sources
PubMed1992

[Mathematical simulation of intracranial condition--Part 1. Linear model stimulation].

We developed a linear mathematical model of the intracranial vessels, which reflects changes of the pulse wave (pulse pressure) of intracranial pressure after ligation of the internal jugular vein. The model composed of eight major variables: 1. resistance of arteries, 2. resistance of small arteries and capillary vessels, 3. resistance of veins, 4. resistance of internal jugular and vertebral veins, 5. compliance of arteries, 6. compliance of small arteries and capillary vessels, 7. compliance of veins and 8. intracranial compliance. All variables are presumed to have linear elements and replaced with electrical elements. The model of neck dissection is expressed as the change of resistance of the internal jugular and vertebral veins. Intracranial condition is expressed as the pulse wave (pulse pressure) of intracranial pressure and driving pressure. After unilateral ligation of the internal jugular vein, the pulse wave of intracranial pressure increased 24% and, after bilateral ligation of the internal jugular vein, it increased 55%. After unilateral ligation of the internal jugular vein, the pulse wave of intracranial pressure increased 27%, and, after bilateral ligation, it increased 79%. When intracranial compliance is normal, the respective ratios of pulse wave of intracranial pressure and driving pressure to cross-sectional area decreased, whereas those after increase of intracranial compliance increased.

Cerebrovascular Circulation↗
PubMed1992

Effect of head-down tilt on intracranial pressure and sagittal sinus pressure during general anesthesia in cats.

The effect of head-down tilt during general anesthesia on intracranial pressure (ICP) dynamics was examined in eight cats. Changes in lateral ventricular pressure (LVP), sagittal sinus pressure (SSP), and effective CSF pressure (ECSFP), which is the driving pressure of cerebrospinal fluid (CSF) absorption, were studied in association with a shift from the horizontal prone position to the 20 degrees head-down tilt position. Both LVP and SSP values were significantly (P < 0.01) increased at 10 min in the head-down tilt position as compared with the control position, remained elevated during the next 110 min, and returned to baseline when the horizontal position was restored. However, ECSFP (expressed by LVP - SSP) was not significantly different from the control value, because changes in LVP and SSP were similar. These results suggest that head-down tilt does not impair CSF absorption.

Analysis of Variance↗
PubMed1991

[Influence of location for jugular venous blood sampling to cerebral circulatory index (CCI)].

When cerebral circulatory index (CCI) expressed as inverse of arterial-jugular venous oxygen content difference is measured, venous sampling at the internal jugular bulb needs to be done in order to avoid mixture with extra-cerebral perfusion blood. To estimate the validity of this point, difference of values calculated with blood obtained simultaneously at the jugular superior bulb, the inferior region and the cerebral sinus were examined in monkeys. As a result, no significant differences were found to result from location of the sampling, and significant correlation between PaCO2 and CCI was recognized. These findings supported the idea that CCI reflects the cerebral blood flow due to PaCO2 changes.

Animals↗
PubMed1989

Changes in distribution of alpha-tocopherol and cholesterol in serum lipoproteins and tissues of rats by dietary PCB and dietary level of protein.

An experiment was conducted with growing rats to examine the influence of dietary addition of 0.1% polychlorinated biphenyls (PCB) and dietary level of protein on the distributions of alpha-tocopherol and cholesterol in serum lipoproteins and tissues. Addition of PCB increased serum alpha-tocopherol. This was mainly due to the increment in the fractions of chylomicrons/very-low-density lipoproteins (VLDL) and high-density lipoproteins (HDL). This chemical also increased serum cholesterol and HDL cholesterol. The contents of alpha-tocopherol and cholesterol in HDL fraction were higher in the high protein groups as compared to the low protein groups, regardless of PCB intake. PCB intake increased the concentrations of alpha-tocopherol in tissues including spleen, lung, kidney, testis, muscle, adipose tissue, and brain. High protein diet increased the levels of alpha-tocopherol in these tissues as compared to low protein diet. PCB intake also increased adrenal alpha-tocopherol, which was potentiated with low protein diet. The increment in liver alpha-tocopherol by PCB intake was observed only in the animals fed on low protein diet.

Animals↗