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Biomedical subjects

S Nitta

Publications and source records attributed to S Nitta.

At least 217 records · Page 12Linked to original sources
PubMed1981

Evaluation of mechanical left ventricular assistance with left atrium to aorta bypass in dogs.

Effects of the left heart bypass (LHB) by the left atrium (LA) to the aorta (AO) shunt on the heart were evaluated by measuring such parameters as tension time index (TTI), diastolic pressure time index (DPTI), DPTI/TTI ratio, coronary blood flow and myocardial oxygen consumption (MVO2) in open-chest dogs. A pneumatically driven bypass pump made of polyurethane was utilized in this study. No significant change of MVO2 was observed with surgical maneuver to connect the LA-AO LHB pump to experimental animals. During synchronous pumping of LHB, TTI decreased by 35%, MVO2 decreased by 56% of the control and DPTI/TTI ratio increased by 79%. However, coronary flow decreased by 35%, presumably due to autoregulation mechanism of the coronary circulatory system. Both synchronous and asynchronous LHB demonstrated the same level of effect in volume unloading. However, significant diastolic augmentation was noted only in the former. LA-AO LHB, which has a sufficient supporting effect and does not damage the ventricular wall, was considered to be very useful for temporary support for the failing heart, especially for postoperative low output state.

Animals↗
PubMed1981

The corrected protein equation to estimate plasma colloid osmotic pressure and its development on a nomogram.

Examining the internal discrepancies of three equations (Landis and Pappenheimer 1965) which represent the relationship between colloid osmotic pressures (COP) and normal human plasma proteins, the authors derived a corrected globulin equation: COPglb = 1.3c + 0.14c2 + 0.006c3 (COP: mmHg, c: protein content, g/100 ml), instead of their COPglb = 1.6c + 0.15c2 + 0.006c3, when A/G (albumin-globulin ratio) = 1.1 as they had described. Revising the former globulin equation again, based upon the current estimate of A/G = 1.8, we derived a new globulin equation. Our new plasma equation, consisting of their albumin equation and our revised globulin equation, is COPpl = alpha (2.8c + 0.18c2 + 0.012c3) + beta (0.9c + 0.12c2 + 0.004c3), where alpha and beta stand for albumin and globulin fraction, respectively. The last, being generalized for plasma with any protein compositions, and closely corresponded to the values directly measured in normal human plasma with variable protein compositions, we developed it on a nomogram for practical use.

Adult↗
PubMed1980

Real-time sound spectroanalysis for diagnosis of malfunctioning prosthetic valves.

A newly developed real-time sound spectroanalyzer was found to be capable of diagnosing malfunction of prosthetic heart valves. Sound spectroanalysis is believed to be superior to other methods such as phonocardiography and echocardiography. This system, developed in our institute, allows display on a cathode ray oscilloscope of five different modes of the valvular click, including the sound spectrograph and section pattern. Analysis of the section pattern allows measurement of the high-frequency components of the valvular click, which is normalized so as to be applicable to a click of any intensity. This parameter is called normalized maximal frequency (NMF). Sound spectroanalyses were carried out 228 times on 127 patients having a prosthetic heart valve. NMF values of normally functioning valves differed characteristically according to the type of valve, but did not change during the postoperative time course. Three of seven patients who had cerebral embolism showed significantly lower NMF values than normal, as did all four patients whose valve had become thrombosed.

Atrial Fibrillation↗