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Biomedical subjects

T Igari

Publications and source records attributed to T Igari.

At least 73 records · Page 4Linked to original sources
PubMed1984

Experimental studies in total artificial heart replacement.

Twenty-seven calves were operated on in our institute for total artificial heart replacement. Thomasu hearts (made by the Thomasu Technical Company, Japan) were used in 21 calves from February 1980 to May 1983. Utah Jarvik 7 hearts were used for the first five calves and the 17th calf. The air-driven Thomasu heart, made of segmented polyurethane, has 95 ml and 85 ml of stroke volume in its left and right sides respectively and showed recognizable function curves in mock circulation systems. There were no satisfactory results in the first 19 cases but the 20th calf survived for 28 days. In 1982, we adopted a new surgical method in which, instead of suturing, a sutureless artificial graft with a stainless steel ring was inserted into the aorta and pulmonary truncus. Since then two out of six calves have survived for more than one month; one of these survived for 66 days. The causes of death after the Thomasu heart replacements were varied. Ten (48%) out of 21 cases had heart trouble and four calves (19%) died through thrombus formation at the inflow and outflow valves. Three calves (14%) died because of mechanical failure of the driving system, two (10%) due to surgical failure, one because of pneumonia, and one due to an abnormal reaction after donor blood transfusion. Our longest surviving calf died after 66 days, because of a broken left blood diaphram though, it remained in excellent condition until its death. There was no thrombus formation in either ventricle, no fibrin net formation and no calcium deposit on the surface of the diaphragm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Experience with a left gastric venacaval shunt for esophageal varices.

A left gastric venacaval shunt for esophageal varices was performed in six patients in attempts to selectively decrease left gastric venous pressure without decreasing portal venous pressure. The left gastric venous pressure decreased from 140-390 mmH2O to 140-200 mmH2O after the left gastric venacaval shunt, while the portal venous pressure remained at 140-370 mmH2O, postoperatively. Even when the portal venous pressure increased up to 320-400 mmH2O with a temporary occlusion of the portal vein, there were no significant changes in the left gastric venous pressure. Five patients are doing well, one to 36 months postoperatively. One patient died of hepatic failure with bleeding on the 21st postoperative day. The left gastric venacaval shunt decreased the incidence of rebleeding and prevented postoperative hepatoencephalopathy and hepatic failure.

Aged↗
PubMed1983

Effects of high salt intake on hemodynamic responses to isometric exercise in normotensive subjects and in patients with essential hypertension.

Hemodynamic responses to isometric exercise were compared between 9 normotensive subjects (NT) and 16 patients with essential hypertension (EH) before and during high salt intake. The subjects were hospitalized and placed on a diet containing 6g of salt per day. Baseline hemodynamic studies were carried out on supine subjects before and 3 min after isometric exercise (30% of the maximal voluntary handgrip). Plasma concentration of norepinephrine (PNE) was also measured. Brachial arterial pressure was directly recorded and cardiac output (CO) was measured by the dye-dilution technique using a cuvette. The hemodynamic studies were repeated on the 5th day of a high salt diet (16g of salt per day). Retention of sodium was calculated on a daily basis by measuring the actual intake of sodium and 24-hour urinary excretion of sodium. Pressor responses to isometric exercise were significantly greater in the EH than in the NT group. Patterns of hemodynamic responses were different in the 2 groups, i.e., the elevation of arterial pressure was maintained by an increase in CO in the NTs, while it was maintained by increases in CO and total peripheral vascular resistance (TPR) in the EHs. The increase in CO was significantly greater in the NT than in the EH group [15 +/- 3 (mean +/- SE) vs 7 +/- 1%, p less than 0.05]. Although the salt loading reduced heart rate similarly in both groups (-9.0 +/- 2.1, p less than 0.01, in the NTs and -11.9 +/- 2.9%, p less than 0.01, in the EHs), the high salt diet did not significantly alter mean arterial pressure (MAP), CO or TPR in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Role of the aldosterone system in the salt-sensitivity of patients with benign essential hypertension.

This study compared responses of blood pressure, plasma concentrations of norepinephrine (PNE) and aldosterone (PA), plasma renin activity (PRA) and urinary excretion of aldosterone during a 5-day period of high salt intake in 11 untreated patients with essential hypertension and 11 age-matched normotensive control subjects. The hypertensive patients all had blood pressures that had been above 160 systolic and/or 90 mmHg diastolic before admission and had decreased to below 150/90 mmHg with only bed-rest and mild salt restriction (6 Gm per day). Sodium balance was also measured before and after high salt intake (16 Gm per day). The hypertensive patients showed both a significant reduction in blood pressure after hospitalization and a significant blood pressure elevation when salt intake was increased. In contrast, no obvious changes in blood pressure were observed in the normotensive subjects. Sodium retention and decreases in PNE and PRA during the high salt period were similar in both groups. However, the reduction in PA and urinary aldosterone excretion in response to excessive salt intake was less pronounced in the hypertensive patients than in the normotensive subjects. The ratio of percentage changes in PA to percentage changes in PRA after salt loading was significantly lower in the hypertensive patients than in the normotensive subjects. In addition, the changes in PA during salt loading were inversely proportional to changes in blood pressure (r = 0.66, p less than 0.01). Thus, it is suggested that the sensitivity of blood pressure to increased dietary salt intake in hypertensive patients may be related to altered aldosterone dynamics, and that the blunt responses of the PA and urinary excretion of aldosterone can be attributed to reduced sensitivity of the adrenal cortex to changes in circulating angiotensin.

Adolescent↗