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Biomedical subjects

F Kosaka

Publications and source records attributed to F Kosaka.

At least 55 records · Page 3Linked to original sources
PubMed1985

The acute effects of prostaglandin E1 on the pulmonary circulation and oxygen delivery in patients with the adult respiratory distress syndrome.

Prostaglandin E1 was administered intravenously to 10 patients who had the adult respiratory distress syndrome associated with severe infection in order to investigate its hemodynamic effects. Infusion of PGE1 significantly decreased the mean pulmonary arterial pressure, mean systemic arterial pressure, pulmonary vascular resistance and systemic vascular resistance, and increased the cardiac index, oxygen delivery and oxygen consumption. No significant difference was noted in the intrapulmonary shunt fraction. These results indicate that administration of PGE1 improves pulmonary hemodynamics and tissue oxygenation in patients with acute respiratory distress syndrome, by reducing right ventricular afterload and increasing the cardiac index.

Aged↗
PubMed1985

Effects of ketamine on the dynorphin levels and the ethylketocyclazocine (EKC) receptor binding in discrete regions of rat brains.

Intraperitoneal (ip) injection of ketamine increased the concentration of dynorphin in the cortex of rat brain, while decreased it in the septal area. The affinity of ethylketocyclazocine (EKC) receptor binding was decreased in the cortex, but increased in the septal area after pretreating the rats with ketamine. This suggests that the dynorphin neuronal system is stimulated in the cortex and suppressed in the septal area by ketamine. In other 5 brain areas, ketamine had no effect on neither dynorphin concentration nor EKC receptor binding. As dynorphin was reported to produce seizure and spike discharge in the cortex while suppressed the hippocampal EEG of rat brain, it is likely that the dynorphin neuronal system may play at least a part in ketamine induced electrophysiological changes in the brain.

Animals↗
PubMed1984

Gas exchange and facilitation of high-frequency ventilation in intrathoracic surgery.

High-frequency ventilation (HFV) of the jet type was evaluated for facilitation of intrathoracic operations because HFV does not necessitate ventilatory movement of the lung and reduces the volume of the lung. The feasibility of HFV as a substitute for the current respiratory management of intermittent positive-pressure ventilation (IPPV) was determined in 12 patients with cancer of the lung by employing two types of HFV-HFV alone (Group 1) and HFV on physiological dead-space volume (VD) (Group 2). For the 6 patients in Group 1, HFV was set at a frequency of 3 Hz and a driving pressure of 0.5 kg/cm2. For the 6 patients in Group 2, HFV was set at 6 Hz with the same driving pressure but was superimposed on a small tidal volume equal to a dead space. High-frequency ventilation facilitated intrathoracic operations because of the disappearance of ventilatory movement and the reduced volume. No significant difference between the groups was found for arterial oxygen tension. Arterial carbon dioxide tension (PaCO2) in patients in Group 1 remained in the normal range, although it was slightly acidotic. The PaCO2 in Group 2 was acidotic. Therefore, it was concluded that HFV alone can be substituted for IPPV in gas exchange and provides good accessibility to the operative field.

Adult↗
PubMed1983

Facilitation of intrathoracic operations by means of high-frequency ventilation.

Gas exchange was measured in eight patients undergoing high-frequency ventilation (HFV) during intrathoracic operations for lung cancer. HFV facilitated the operation because the exposed lung moved only slightly to ventilate and stayed in a less expanded state. Intermittent positive-pressure breathing (IPPB) (control) was switched to HFV 20 minutes after the pleural cavity was opened. HFV either was conducted alone (HFV alone) or was superimposed on a hypoventilation equal to the dead space (HFV on VD). The driving pressure and frequency of HFV were set at 0.5 kg/cm2 using 3, 6, and 12 Hz with an FI02 of 0.50. The only statistically significant difference in arterial PO2 between IPPB and HFV occurred when the HFV alone was used at 12 Hz. Significant differences in arterial PCO2 values existed between IPPB and HFV alone when the HFV was at 6 and 12 Hz, and between HFV alone and HFV on VD at 12 Hz. The arterial pH values were lower at 6 and 12 Hz in HFV alone and were significantly different from pH values during IPPB. Acidosis was due to the respiratory component of HFV only. The metabolic component remained unchanged. It was concluded that the gas exchange was adequately maintained at 3 Hz during HFV alone. The intrathoracic operation was facilitated by less movement as the frequency increased, although the lung volume tended to expand. The gas exchange, particularly the elimination of carbon dioxide, worsened during the use of HFV alone. However, HFV on VD continued to maintain an adequate gas exchange and facilitate the operation.

Adult↗
PubMed1982

Direct withdrawal of zones during preparative capillary type isotachophoresis.

This study used a Shimadzu IP-1B capillary type isotachophoretic apparatus with a potential gradient detector. An ipp-1 withdrawal cell was fitted to this and a technique for withdrawing individual components directly through this port was developed using a microsyringe. The recovery rate was up to 45% for individual target components. When 100% withdrawal of the target component was attempted by withdrawing a volume four times the calculated volume (so that the zones both before and after the target component were also included), the best recovery rate was only 78%. In all cases, the results varied less than 3%. The limit for analysis of individual components of a 0.01 M solution was around 3 microliters. If this volume was exceeded, the ion quantity was too large for the volume of the microcapillary tube and mixed zones formed such that complete separation and analysis of individual components became impossible.

Citrates↗
PubMed1980

Myelin-like structures seen intracellularly in renal tubule cells subjected to ischemia.

Renal cortex was studied during experimentally induced ischemia. A transient increase in anerobic glycolysis occurred with concomitant swelling of both the Golgi apparatus and mitochondria. These intracytoplasmic organelles underwent marked changes in their intracellular positions. Infolding of cytoplasmic membrane at the basal side of proximal tubule cells increased in complexity and proceeded to enclose various intracytoplasmic microorganelles such as mitochondria and the Golgi apparatus. Piling up in layers was particularly marked around mitochondria. This piling up appeared as myelin-like structures on the free surface of, and within, proximal tubule cells, and followed disruption of the brush border at the free surface. Histological examination of thin sections showed that the fused portions of this brush border were actually brush border cytoplasmic membrane piled up in layers giving the appearance of myelin-like structures. After two hours of ischemia, parts of the membrane of these myelin-like structures were disrupted. Large vacuoles developed and these were thought to be related to the large vacuoles seen during cell degeneration.

Acid Phosphatase↗
PubMed1978

Scanning electron microscopy of the ischaemic kidney--changes in the surface microstructure of glomerular epithelial cells.

Domestic rabbits were used to study the changes that occur during ischaemic conditions in the kidney. With a scanning electron microscope, the microcellular changes at the surface of gomerular epithelial cells were observed regularly from the onset of ischaemia until five hours later. After one hour of ischaemia, the surface of the glomerular epithelial cells showed mild swelling and some change in its smooth appearance. One part had taken on a sponge-like appearance. After 2.5 hours of ischaemia, the epithelial cells had atrophied and the entire cell surface was clearly sponge-like. It was no longer possible to distinguish the small pore-like structures that had been seen on the cell surface in the normal. Moreover, 2.5 hours of ischaemia was the time when, biochemically, cell metabolism had completely ceased and the permeability of the cell membrane had altered. The cell was considered to have undergone irreversible change by this stage. After 5 hours of ischaemia, cells were markedly atrophied and the appearance of the surface had become even more sponge-like.

Animals↗