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Biomedical subjects

A Ohmura

Publications and source records attributed to A Ohmura.

15 recordsLinked to original sources
PubMed1986

Gain of slow-phase velocity of optokinetic nystagmus.

Although slow-phase velocity of optokinetic nystagmus (OKN) increases according to the increase of stimulus velocity, it is not obvious whether both are quite equal or not. In this study, gain of slow-phase velocity in OKN response to stimulation velocity was analyzed by two methods of stimulation, constant acceleration, and constant velocity stimulation. In our observation, the gain of slow-phase velocity was not equal to 1.0 even at low-speed stimulation. On the other hand, the number of nystagmus almost corresponded to the number of stimulation stripes passing through the center of an OK-drum up to high-speed stimulation. The results of this study indicate that pursuit eye movement of slow-phase OKN should not be quite equal to that of the eye tracking test, i.e. being required to continuously look at a moving spot.

Acceleration↗
PubMed1982

Effects of halothane and sodium nitroprusside on renal function and autoregulation.

The effects of sodium nitroprusside and halothane on renal autoregulation and kidney function were studied in 14 mongrel dogs at mean arterial pressures of 120, 100, 80, 60 and 40 mm Hg. In group 1, stepwise decreases in mean arterial pressure were achieved by increasing the halothane concentration. In group II, mean arterial pressure was decreased by infusing sodium nitroprusside during halothane anaesthesia. In group I, renal blood flow decreased significantly at mean arterial pressures of 100, 80, 60 and 40 mm Hg. In group II, renal blood flow was well maintained at mean arterial pressures of 100 and 80 mm Hg, but decreased significantly at 60 and 40 mm Hg; at these low pressures flow was greater in group II than in group I. There were no significant differences between two groups in inulin clearance, inulin clearance/renal plasma flow, urine output, urine osmolarity and sodium excretion rate. Significantly larger fractions of cardiac output were distributed to the kidneys in group I.

Animals↗
PubMed1976

Cardiac effects of succinyldicholine and succinylmonocholine.

The present study evaluated possible contribution of succinylmonocholine in producing serious cardiovascular effects with or without succinyldicholine, using albino rabbits as the experimental animal. Forty-eight experiments were performed, 22 in vivo and 26 in vitro (Langendort heart). Succinyldicholine and succinylmonocholine administered separately or together produced an immediate bradycardia in vivo as well as in vitro. The combination of these drugs had a direct arhythmogenic effect as well as an indirect reflux mediated cardiac effect. When succinyldicholine was given within five minutes following a dose of succinylmonocholine there was significant nodal and ventricular ectopic beats, but no bradycardia. Dysrhythmias in in vivo hearts were abolished by cord trans-section, trimethaphan and reserpine pretreatment. There was no evidence in vivo that succinylmonocholine produced more serious bradycardia, dysrhythmias or hypotension than succinyldicholine,

Animals↗
PubMedDate not supplied

Epinephrine-induced arrhythmias: effect of exogenous prostaglandins and prostaglandin synthesis inhibition during halothane-O2 anesthesia in the dog.

Prostaglandins (PG) modify sympathetic and parasympathetic neurotransmission and have antiarrhythmic properties. Inhibitors of PG synthesis sensitize the heart to certain experimentally induced arrhythmias. This study examined the arrhythmogenic dose (AD) of epinephrine in dogs during halothane-O2 anesthesia as modified by the infusion of PG and by treatment with an inhibitor of PG synthesis. Dogs were anesthetized with 1.25 MAC halothane. The AD of epinephrine was established by a series of 3-minute epinephrine infusions at 10-minute intervals. The AD of epinephrine was then redetermined during infusions of PG(PGE1--1 microgram/kg/min and PGF2 alpha--1 microgram/kg/min), after indomethacin, 3 mg/kg, and after aminophylline, 10 mg/kg. The AD remained unchanged from control during both of the PG infusions and following indomethacin. Only following aminophylline did the AD decrease significantly. Our study suggests that pretreatment of surgical patients with nonsteroidal antiinflammatory drugs which inhibit PG synthesis does not increase the likelihood of ventricular arrhythmias during halothane-O2 anesthesia.

Aminophylline↗