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Biomedical subjects

T Inasaka

Publications and source records attributed to T Inasaka.

18 recordsLinked to original sources

Recovery from alexia without agraphia: report of an autopsy.

The patient is a 58-year-old Japanese teacher of German literature who suffered twice from cerebrovascular accidents, showing alexia without agraphia. Pathological examination showed an old infarct in the posterior two-thirds of the fusiform and almost the whole lingual gyrus, involving the posterior border of the parahippocampal gyrus in the left hemisphere. The left cuneus and the calcarine cortex were preserved. There was degeneration of the lower third of the splenium of the corpus callosum, extending to its occipital radiation and tapetum on both sides. Comparing clinico-pathological findings of the 31 known autopsy cases, it was proposed that the lesion of the left spleno-lingual system produces alexia without agraphia but it may ameliorate. In addition, when spleno-cuneate system is also involved alexia becomes persistent and it may accompany object agnosia or optic aphasia.

Agraphia

Effects of angiographic contrast media on sino-atrial nodal function.

Injection of meglumine diatrizoate (Renografin-76) into the selectively perfused sinus node artery of the dog produces bradycardia which is unaltered by autonomic blockade or by changes in sinus node artery pressure. Contrast agents and other hyperosmolar substances prolong the R-R interval in proportion to their osmolarity. Selective injection of contrast media into other cannulated segments of the coronary tree produces no change in heart rate. Transfemoral arteriography, however, produces bradycardia with both right and left coronary injections. Both direct and reflex sinus node depression occur with coronary arteriography in the dog. Direct effects are mediated by hyperosmolarity.

Adrenergic beta-Antagonists

Relationships of left ventricular systolic time intervals with hemodynamic variables in intact and failing hearts.

Deviation of systolic time intervals (STI) from the regression lines obtained from 122 normal subjects was studied in 22 healthy adults (Group 1), 18 N.Y. functional class I cardiac patients (Group II) with ischemic (IHD) or primary myocardial disease (PMD), and 15 similar patients (pts) but N.Y. functional class II with prior heart failure (Group III). STIc (corrected for heart rate) were normal in Groups I and II. Supine exercise caused shortening of pre-ejection period PEPc and prolongation of left ventricular ejection time ETc in both groups. Group III pts had a significantly longer PEPc and shorter ETc at rest. Supine exercise caused further prolongation of PEPc and a slight prolongation of ETc in this group. In 8 mongrel dogs, the effect of controlled changes of hemodynamic variables on STI was studied with intact hearts and repeated after myocardial impairment has been induced by pentobarbital. Doubling of venous return while the heart was intact produced changes in STI similar to the effects of supine exercise in Groups I and II human subjects. With myocardial impairment, comparable increase in venous return had an effect on STI similar to the effect of supine exercise Group III patients. Controlled increase in each of heart rate or blood pressure, with other hemodynamic variables kept constant, produced changes in STI different from the effect of supine exercise on human subjects. The study suggests that the value of supine exercise induced changes in STI in reflecting left ventricular performance is attributable primarily to increased volume load. In this resepct supine exercise is probably superior to other forms of exercise in disclosing impaired left ventricular performance.

Adolescent

Changes of cardiac performance in renal failure.

Clinical and experimental studies were carried out in order to evaluate the role of myocardial dysfunction in the genesis of circulatory congestion associated with renal failure. Among the patients with chronic renal failure, those with circulatory congestion had greater blood volume and higher venous pressure while lower cardiac index and stroke work index than those without circulatory congestion. After peritoneal dialysis, although blood volume and venous pressure decreased in both groups, cardiac index increased in the former while it decreased in the latter group. In 15 dogs, acute renal failure was produced by ligating both ureters. As uremia developed, blood volume and left ventricular end-diastolic pressure increased with or without an increase in cardiac index. The depression of ventricular function curve was evident in all the dogs. The peritoneal dialysis performed at this stage resulted in a prompt recovery of left ventricular end-diastolic pressure with minimum change in cardiac index. The measurement of dp/dt/IIT also indicated a depression of myocardial contractility at uremic stage and its recovery after dialysis. We conclude that impairment of myocardial function is implicated in the development of circulatory congestion in renal failure.

Acute Kidney Injury

Influence of changes in heart rate, aortic pressure and flow rate upon experimental coronary insufficiency.

This study was designed to evaluate the role of heart rate, aortic pressure, and aortic flow in the development of coronary insufficiency following acute coronary stenosis. In dogs, each of these parameters was controlled at a predetermined level while the left anterior descending coronary artery was constricted with a small screw clamp. The critical coronary pressure (CCP), i.e. the pressure below which a rise of left atrial pressure could be detected, was determined at various levels of hemodynamic load. Increases in aortic pressure, elevation of the heart rate and an increase in aortic flow rate were all associated with an elevation of the CCP and an increase in tension-time index (TTI). The changes in CCP were most striking when TTI was increased by aortic flow rate change. These findings suggest that with high aortic pressure, further constriction of coronary artery is required to precipitate coronary insufficiency, that the level of pacing required to induce coronary insufficiency is a useful index in assessing the degree of coronary stenosis, and that an augmentation of aortic flow rate is an important factor in the initiation of coronary insufficiency.

Animals