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Biomedical subjects

F Yamamoto

Publications and source records attributed to F Yamamoto.

At least 199 records · Page 11Linked to original sources
PubMed1986

The neuronal pathway from the flocculus to the oculomotor nucleus: an electrophysiological study of group y nucleus in cats.

In 17 cats anesthetized by Ketalar, neuronal activities were recorded extracellularly by a tungsten microelectrode placed in the group y nucleus of the vestibular nuclei. Forty-seven of 139 neurons tested were activated antidromically by stimulation of the superior rectus and inferior oblique subdivisions of the oculomotor nucleus. Twenty-five of these 47 neurons ceased their spontaneous discharges after stimulation of the caudal zone of the flocculus. In addition, 18 out of these 25 units responded polysynaptically to stimulation of the vestibular nerve.

Action Potentials↗
PubMed1986

Comparative study of four arginine ester hydrolases, ME-1, 2, 3 and 4 from the venom of Trimeresurus mucrosquamatus (the Chinese habu snake).

Four arginine ester hydrolases, ME-1, 2, 3 and 4 from the venom of Trimeresurus mucrosquamatus had been isolated and characterized by Sugihara et al. (1980, 1981, 1982, 1983). Immunologically, ME-1, 2, 3 and 4 are identical. The four enzymes hydrolyzed Pro-Phe-Arg-MCA and z-Phe-Arg-MCA. Furthermore, ME-2 slightly hydrolyzed Boc-Val-Pro-Arg-MCA, Boc-Phe-Ser-Arg-MCA and Boc-Ile-Glu-Gly-Arg-MCA. ME-1 cleaved almost simultaneously the Arg(22)-Gly(23) and Phe(25)-Tyr(26) bond of oxidized insulin B chain. ME-2 and 3 also hydrolyzed the same bond of insulin B chain, but the activity was not as potent as ME-1. ME-4 did not cleave the substrate. The four enzymes hydrolyzed C-terminal of arginine in the biologically active peptides. Four arginine ester hydrolases showed fibrinogenolytic activity. ME-1 and 2 first cleaved B beta-chain and then A alpha-chain. On the contrary, ME-3 and 4 cleaved A alpha- and B beta-chain simultaneously. The four enzymes also hydrolyzed fibrinogen in plasma cleaving B beta- and gamma-chain and slightly digesting A alpha-chain. The various inhibitors affected TAME (tosyl-arginine-methylester) and the fibrinogen hydrolytic activity of the four enzymes. All four enzymes had fibrinolytic activity.

Amino Acid Sequence↗
PubMed1986

Respiratory care of pediatric patients requiring prolonged intubation after cardiac surgery.

Pediatric patients requiring intubation more than 4 days after cardiac surgery can experience many respiratory and other problems. We found that 48 of 264 pediatric patients could not be extubated within 4 days after open-heart surgery because PaO2 was less than 75 torr and PaCO2 was over 45 torr on an inspired oxygen fraction of 0.4. Most of the 48 patients were under 12 months old, had pulmonary hypertension and/or complex cardiac anomalies, and were not hemodynamically stable and/or fully conscious. The intensity of long-term intubation was attributed to cardiovascular or respiratory complications and multiple organ failure. At the time of extubation, water infusion was maintained below 80 ml/kg X day and positive water balance below 15 ml/kg X day. Calories and amino acid were maintained over 70 kcal/kg X day and 1.5 g/kg X day, respectively.

Body Water↗
PubMed1986

[Efficacy and limitation of postoperative barbiturate therapy in severe head injury].

Efficacy and limitation of barbiturate therapy employed as postoperative treatment for acute traumatic intracranial hematomas were studied in 20 patients. The clinical cases in this series included 15 males and 5 females with mean age of 41.8 years who all were operated on for intracranial hematomas within 3 days after injury. Glasgow Coma Scale (GCS) score was less than 7 in all instances and intracranial pressure (ICP) as well as arterial pressure was monitored postoperatively with Gaeltec and Gould transducers. Barbiturate therapy (5 mg/kg of thiopental as an initial dose and loading dose of 2-3 mg/kg/hour) was given when ICP rose above 20 mmHg and maintained for 3 days after operation. The outcome of the patients was assessed by Glasgow Outcome Scale 3 months after injury. The response of barbiturate on ICP and the changes of cerebral perfusion pressure (CPP) during the therapy in relation to the outcome were studied. Final outcome of the patients revealed 5 of good (good recovery and moderate disability), 3 of poor (severe disability and vegetative state) outcomes and 60% of mortality rate. Eleven out of 20 patients responded to barbiturate therapy and 0-20 mmHg of ICP reduction (mean reduction of 10 mmHg) was obtained in these cases. Among these cases, 2 out of 3 dead patients were older than 60 years. There were no responses of barbiturate in 7 patients to whom the therapy was started when ICP rose above 40 mmHg. No response of the therapy on ICP was also observed in the patients with GCS score of 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Usefulness of left ventricular volume in assessing tetralogy of Fallot for total correction.

Ninety-one patients with tetralogy of Fallot underwent intracardiac repair between 1978 and 1981. One patient died from left-sided heart failure. Retrospective analyses of this death revealed a significant decrease of the left ventricular (LV) end-diastolic volume index (EDVI) of 21 ml/m2 (36% of normal). Results of early postoperative hemodynamic studies after total correction of this anomaly suggested that an EDVI of 30 ml/m2 is the minimal requirement for adequate cardiac output postoperatively. Based on these data, 3 patients with decreased LV volume with EDVI of around 30 ml/m2 were challenged with the primary repair with success, although they required atrial pacing and catecholamine support postoperatively to maintain adequate left atrial pressure and cardiac output. From these results, it is recommended that patients with tetralogy of Fallot and an EDVI of 30 ml/m2 or more can be considered as candidates for the primary repair, but that patients with an EDVI of less than 30 ml/m2 should be palliated once by systemic-to-pulmonary arterial shunt procedures. Subsequent total correction should be performed after sufficient LV growth for those patients.

Adolescent↗