Hideaki Sakio

Exaggerated responses to chronic nociceptive stimuli and enhancement of N-methyl-D-aspartate receptor-mediated synaptic transmission in mutant mice lacking D-amino-acid oxidase.

Formalin-induced nociceptive behaviors and N-methyl-D-aspartate (NMDA) subtype glutamate receptor-mediated excitatory synaptic transmission were analyzed in mutant mice lacking D-amino-acid oxidase, which catalyzes the oxidative deamination of D-amino acids. The second phase of the formalin-induced licking response, a part of which is known to be mediated by NMDA receptors in the spinal cord, was significantly augmented in mutant mice. NMDA receptor-mediated excitatory postsynaptic currents recorded from spinal cord dorsal horn neurons by tight-seal whole-cell methods were significantly potentiated in mutant mice. The present observations provide another line of evidence that D-serine functions as an endogenous coagonist at the glycine site of NMDA receptors, and raise the possibility that D-amino-acid oxidase exerts a neuromodulatory function by controlling the concentration of D-serine in the central nervous system.

Comparison of hemodynamic effects of enhanced external counterpulsation and intra-aortic balloon pumping in patients with acute myocardial infarction

This study compared the hemodynamic effects of enhanced external counterpulsation and intra-aortic counterpulsation in patients with acute myocardial infarction. Results demonstrated similarity between these 2 methods, except enhanced external counterpulsation had a transient effect of increasing right atrial pressure, pulmonary capillary wedge pressure, and cardiac index.

A simple method for detecting plasma propofol.

Implications We measured plasma propofol levels by head space-gas chromatography analysis using solid-phase microextraction. This method saves time, and does not require elimination of interfering substances in the plasma. The coefficient variation was ±5% to ±30%. The detection limit was 10 ng/mL.

Gastric PCO2 monitoring system based on a double membrane type PCO2 sensor

Abstract Gastric PCO2 monitoring during canine hemorrhagic shock encountered occasional baseline drift to higher direction when conventional PCO2 sensor was used. As a result of chemical analysis of gastric juice of dogs and human, hydrogen sulfide and acetic acid were identified as causative compounds. It was speculated that these weak acid molecules would permeate gas-permeable silicone membrane to be accumulated in the inner solution of Severinghaus-type PCO2 sensors. In order to prevent this phenomenon, double-membrane type PCO2 sensor was constructed. In this sensor, acid-neutralizing solution was installed between the inner and the outer membranes in order to dissociate weak acid molecules into corresponding ions, which can not diffuse into the inner silicone membrane. In addition, Cu2O particles were mixed in the inner silicone membrane to trap hydrogen sulfide in this membrane. It was confirmed by experiments in vitro that the readings of improved gastric PCO2 sensors were not affected by acetic acid or hydrogen sulfide. As a result of a preliminary clinical evaluation, continuous monitoring of gastric PCO2 was carried out for 72 h without detectable baseline drift or the change of sensitivity.

Effects of dibutyryl cyclic AMP on hemodynamics and plasma catecholamine concentrations during ammonium chloride-induced metabolic acidosis in anesthetized dogs

We investigated, using anesthetized dogs, the effect of dibutyryl cyclic AMP (db-cAMP), a derivative of cyclic AMP (cAMP), on cardiovascular variants and plasma catecholamines during metabolic acidosis. These effects were also compared with those of dopamine. The db-cAMP and dopamine were infused at 200 and 20 micrograms/kg.min, respectively. Metabolic acidosis (pH 7.00, PaCO2 40 torr) was induced by the iv infusion of 1-M ammonium chloride solution (NH4Cl). In the normal acid-base state, both db-cAMP and dopamine significantly increased cardiac output and decreased systemic vascular resistance (SVR). During metabolic acidosis, db-cAMP increased cardiac output by 69 +/- 14% and decreased SVR by 36 +/- 2%, while dopamine did not produce changes in cardiac output and increased SVR. Dopamine caused an elevation of epinephrine and norepinephrine in the normal acid-base state, but db-cAMP did not. During metabolic acidosis, dopamine significantly increased the plasma concentration of epinephrine and norepinephrine, while db-cAMP significantly decreased epinephrine concentration. These results suggest that db-cAMP may have a more beneficial effect on hemodynamics compared with dopamine when therapeutic support is needed during circulatory insufficiency with severe metabolic acidosis.

A Personal Computerized Anesthesia Recording System — With Multiplexer and Serial Interfaced Monitors

Recent progress of monitoring technology for anesthetic management and critical care medicine was much remarkable. These progress was not only in monitoring accuracy but also in computer interfaces. Many monitoring devices were installed RS-232C communication interfaces in standard. Also the progress in the personal computer (PC) is the most remarkable in hardware and software environments. In these environments, the authors developed an anesthesia recording system on PC, using RS-232C serial interfaced monitors and the RS-232C multiplexer.

Continuous Cardiac Output Monitoring System Applying Fick’s Principle

A continuous cardiac output monitoring system was developed by the authors applying Fick’s principle using a pulseoximeter, an oximetry thermodilution SwanGanz catheter system and a metabolic gas monitor. To calculate cardiac output by Fick’s method (CFCO), all monitors were connected to a personal computer via serial interfaces. CFCO was compared simultaneously to the cardiac output by a thermodilution method (TDCO).