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Hirokazu Saito

Publications and source records attributed to Hirokazu Saito.

5 recordsLinked to original sources
PubMed2007

A flexible transcutaneous oxygen sensor using polymer membranes.

A wearable and flexible oxygen sensor for transcutaneous blood gas monitoring was fabricated and tested. The sensor has a laminar film-like structure, which was fabricated by pouching KCl electrolyte solution by both non-permeable (metal weldable) sheet and gas-permeable membrane with Pt- and Ag/AgCl-electrodes patterned using microfabrication process. The electrolyte solution was fixed only by heat-sealing the edges of the weldable membranes without any chemical adhesives. The wearable oxygen sensor (thickness: 84 mum) was applied to the electrochemical measurement with a constant potential of -600 mV vs. Ag/AgCl, thus obtaining the calibration range to dissolved oxygen (DO) from 0.0 to 7.0 mg/l with a correlation coefficient of 0.998 and the quick response time (53.4 s to 90% of a steady-state current), which operate similarly to a commercially available oxygen electrode. The sensor was also utilized to transcutaneous oxygen monitoring for healthy human subject. The sensing region of the wearable oxygen sensor was attached onto the forearm-skin surface of the subject inhaling various concentrations of oxygen. As a result of physiological application, the output current was varied from -6.2 microA to -7.8 microA within 2 min when the concentration of inhaling oxygen was changed from atmospheric air to 60% oxygen. Thus, the transcutaneous oxygen was successfully monitored without any inconveniences such as skin inflammation, etc.

Biosensing Techniques↗
PubMed2004

Postoperative analgesic effect of epidural neostigmine and plasma cortisol and IL-6 responses.

STUDY OBJECTIVES: To examine whether epidural administration of neostigmine reduces the stress and inflammatory responses thereby improving postoperative pain status. DESIGN: Randomized, double-blinded clinical study. SETTING: Operating rooms and wards of a university hospital. PATIENTS: 40 ASA physical status I patients undergoing lower open abdominal surgery for benign gynecological disease. INTERVENTIONS: Patients were randomly divided into four groups to receive different doses of epidural neostigmine (0, 0.05, 0.1, or 0.15 mg) with mepivacaine (100 mg) before general anesthesia induction. MEASUREMENTS: The plasma levels of cortisol and interleukin-6 (IL-6) were determined perioperatively. The patients' pain rating was assessed by visual analog scale (VAS) in the postoperative period. MAIN RESULTS: Epidural neostigmine at all doses significantly reduced the plasma levels of cortisol in the early surgical period; however, IL-6 levels were not affected by the neostigmine. The VAS scores were significantly decreased at 2 hours after the end of surgery by all doses of epidural neostigmine used in this study. CONCLUSIONS: The preincisional epidural neostigmine transiently suppresses the stress responses during surgery and improves postoperative analgesia in patients undergoing lower open abdominal surgery.

Adult↗
PubMed2003

Effect of volatile anesthetics on steroidogenesis in isolated bovine adrenocortical fasciculata cells.

To examine effects of volatile anesthetics (VAs) on steroidogenesis, cell suspensions of isolated bovine adrenocortical cells were incubated with several steroidogenic agents in the presence or absence of halothane and sevoflurane. The adrenocortical cells were dispersed by trypsin digestion of bovine adrenal cortex. The cortisol level was measured fluorometrically. VAs inhibited adrenocorticotropic hormone-, acetylcholine-, angiotensin-II-, and KCl-stimulated steroidogenesis in a concentration-dependent manner with extracellular Ca(2+). However, dibutyryl cyclic adenosine monophosphate-stimulated steroidogenesis was not inhibited by VAs. These results suggest that VAs inhibit steroidogenesis by blocking Ca(2+)-influx from the extracellular space without influencing the action of intracellular cyclic nucleotides.

Acetylcholine↗