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Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 1,333 records · Page 74Linked to original sources
PubMed1981

Lipid and apolipoprotein levels in patients with nephrotic syndrome.

Plasma lipids and 6 plasma apolipoproteins (apoA-I, apoA-II, apoB, apoC-I, apoC-II and apoC-III) were studied in 23 patients with nephrotic syndrome. The elevated total cholesterol, triglyceride and apoB levels in nephrotic patients decreased gradually, after the disappearance of proteinuria. During the acute stage high density lipoprotein cholesterol, as well as the sum of apoA-I and apoA-II were similar in the patients and the controls. ApoA-I and apoA-II were transiently elevated during the recovery stage. All three apoC proteins (apoC-I, apoC-II and apoC-III) were elevated during the acute stage. A significant decrease in apoC-I, apoC-II and apoC-III was observed during the first 3 weeks after normalization of the urine protein. The ratio of apoC-II/apoC-III was reduced during the first 4 weeks after normalization of urine protein and then returned to the control level. The results suggest that as far as total levels are concerned, changes of apoC-II, apoC-III and the ratio of apoC-II/apoC-III appear to have no effect on the development of hyperlipidemia in th nephrotic syndrome.

Adolescent↗
PubMed1981

Some calculations on the amount of selfish DNA.

A population genetical theory is developed to treat the amount of selfish DNA in a genome. We assume that the selfish DNA consists of replicating units and that it evolves by multiplication within a genome, exchange between genomes, and random genetic drift at reproduction. Special reference is made to the mean and variance of the number of replicating units per genome in the population. Under the assumption of no systematic evolutionary pressure, the number of units changes randomly with time, and its variance increases by replication process. Although under certain circumstances the variance increases also by exchange process, under ordinary circumstances this process tends to decrease the variance. Random genetic drift also reduces the variance. The relationship between the mean and variance at equilibrium of the number of replicating units per genome in the population was derived. The results obtained will be useful in understanding various observations on repeated DNA which presumably does not contain genetic information and which is likely to be selectively neutral.

DNA↗
PubMed1981

Persistence of the circadian rhythm of REM sleep: a variety of experimental manipulations of the sleep-wake cycle.

Many studies of nocturnal sleep, daytime naps, and phase shifts of sleep time indicate that rapid eye movement (REM) sleep has a circadian rhythm with an acrophase in the early morning, whereas slow wave sleep (SWS) correlates positively with the length of prior wakefulness. We confirmed that REM sleep has a stable circadian variation; large REM sleep amounts occurred in morning naps despite increase of SWS, owing to 1 night of total sleep deprivation. Heart rate and oral temperature both continued to show a circadian rhythm in spite of 1 night of total sleep deprivation. The lowest point of both cycles occurred in the early morning and the highest point in the late afternoon. The amount of REM sleep was largest near the low point of the circadian cycle of oral temperature and heart rate, and smallest at the high point, indicating a phase reversal relationship between the circadian rhythm of REM sleep and the autonomic functions. During 1 week of absolute bed rest under entrained conditions, subjects were most able to sleep near the low point of their oral temperature cycle and least able to sleep near the high point, and the amount of REM sleep was largest near the low point of the oral temperature and smallest at the high point.

Adult↗
PubMed1981

Body surface isopotential maps of experimentally induced transient right bundle branch block.

The characteristic patterns of the epicardial activation and body surface isopotential maps (MAPs) were examined in experimental transient right bundle branch block (RBBB) produced by pressing the main stem of right bundle mechanically. During the recovery from the complete block, various degrees of incomplete RBBB (IRBBB) were obtained. The epicardial activation of IRBBB spread in almost normal fashion with delayed right ventricular epicardial breakthrough. And the MAPs manifested intermediate patterns between those obtained in control and in complete RBBB (CRBBB). The MAP patterns of IRBBB were classified into the following 3 groups by the difference of the localized bend of isopotential lines reflecting the epicardial breakthrough. In the advanced IRBBB with QRS prolongation over 25%, the epicardial breakthrough of the left ventricle was detected on the MAPs. In the moderate IRBBB with QRS prolongation around 20%, in addition to the left ventricular breakthrough the right ventricular breakthrough was detected at the center of the anterior chest. In the mild IRBBB with QRS prolongation less than 15%, only the right ventricular breakthrough was detected. These findings indicate usefulness of MAPs for diagnosing the severity of IRBBB due to the damage to the main right bundle. Moreover, these MAP patterns in IRBBB of main right bundle can be distinctly differentiated from the IRBBB MAPs resulting from incisional interruption of lateral branches of right bundle. The present findings also suggest the usefulness of MAPs in diagnosing the site of the conduction disturbance resulting in IRBBB.

Animals↗
PubMed1981

Correlation between body surface isopotential maps and left ventriculograms in patients with old anterior myocardial infarction.

In 30 patients with old anterior myocardial infarction, body surface isopotential maps were correlatively studied with left ventriculographic findings. In 25 patients with ventricular asynergy restricted to the anterior segments, surface potential abnormalities due to infarction were observed during specific phases of QRS and in specific portions of the chest surface depending on the location and extent of severe ventricular asynergy (akinesis and dyskinesis). However, the remaining 5 patients with co-existing severe asynergy in the inferoposterior segment, showed body surface potential maps quite different from those of the above 25 patients. It was suggested that body surface isopotential maps were useful in detecting the location and extent of ventricular severe asynergy in patients with old anterior myocardial infarction.

Adult↗
PubMed1981

Depression of heart function after angiotensin II infusion in patients on chronic hemodialysis.

The response of heart function to angiotensin II (AT II) was studied in 18 patients on regular hemodialysis. The mean age was 33 years and they had been dialyzed for 55 months in the average. AT II was infused from a large vein and systolic blood pressure was raised by 40 mmHg. Before and after the change in blood pressure, M-mode echocardiogram of left ventricle was recorded. Left ventricular enddiastolic dimension, stroke index and cardiac index were found to be normal except for 9 patients who showed cardiac index above 4.0L/min/m2. No significant change was found in these parameters after the rise of blood pressure by AT II. Control ejection fraction (EF) was slightly but nonsignificantly lower in the patients than the healthy subjects; 0.73 +/- 0.13 vs. 0.80 +/- 0.05. Though significant falls in EF were found in the patient and in the healthy group, the former showed a profound depression of EF to 0.64 +/- 0.10. This value was significantly lower than the value of the latter group; 0.76 +/- 0.04 (p less than 0.01). Since none had overt heart failure, a depression of EF after AT II can be regarded as subclinical abnormality of heart function. AT II will be useful to detect this limited reserve of heart function in patients on regular hemodialysis who may show normal function at rest.

Adult↗
PubMed1981

Hemodynamic study of ischemic limb by velocity measurement in foot.

By means of a tracer technique with 99mTc-pertechnetate, provided with seven zonal regions of interest, 6 mm in width, placed at equal spaces of 18 mm, from the toe tip to the midfoot at a right angle to the long axis of the foot, arterial flow velocity in the foot during reactive hyperemia was measured. The mean velocity in the foot was 5.66 +/- 1.78 cm/sec in 14 normal limbs, 1.58 +/- 1.07 cm/sec in 29 limbs with distal thromboangiitis obliterans (TAO), 0.89 +/- 0.61 cm/sec in 13 limbs with proximal TAO, and 0.97 +/- 0.85 cm/sec in 15 limbs with arteriosclerosis obliterans (ASO). The velocity returned to normal in all 12 limbs after successful arterial reconstruction, whereas the foot or toe blood pressure remained pathologic in 9 of the 12 limbs postoperatively; the velocity reverted to normal in 4 of 13 limbs after lumbar sympathectomy. When the velocity was normalized after operation, the ulceration healed favorably, and the ischemic limb was salvaged. The most characteristic feature of peripheral arterial occlusive disease of the lower extremity was a stagnation of arterial circulation in the foot, and the flow velocity in the foot was a sensitive predictive index of limb salvage.

Adult↗
PubMed1981

Implications of the existence of two states of beef liver mitochondrial adenosine triphosphatase as revealed by kinetic studies.

The results of studies on the initial velocity in hydrolysis reactions of ATP and other nucleoside triphosphates with beef liver mitochondrial ATPase can be summarized as follows. 1. Double reciprocal plots of substrate concentration vs. initial velocity were linear for all the nucleoside triphosphates tested except for ATP, which showed a negative cooperativity. 2. Bicarbonate ion increased the rate of ATP hydrolysis and diminished its negative cooperativity, whereas hydrolysis of other nucleoside triphosphates was only slightly affected by the anion. 3. An excess of nucleoside triphosphate apparently inhibited its own hydrolysis for all kinds of nucleoside triphosphates tested, whereas an excess of magnesium ion apparently inhibited only ATP hydrolysis. 4. Inhibition of ATPase activity with an excess of magnesium ion was no longer observed when the reaction was carried out at low temperature (10 degrees C) or in the presence of sulfate. Under these conditions, the kinetics of ATP hydrolysis were apparently of simple Michaelis-Menten type. These observations suggest the existence of two states ("A" and "N") of beef liver mitochondrial ATPase. The state "A" is characterized by phenomena specifically affecting ATP hydrolysis, such as the inhibition by excess magnesium ion, and the negatively cooperative profile in the dose-response curve of ATP. In the state "N" proceed the hydrolysis reactions of other nucleoside triphosphates and of ATP under limited conditions. The two states ("A" and "N") can be related to an enzyme model with a catalytic site and a regulatory site. Computer stimulation revealed that such a model could account well for the experimental data.

Adenosine Triphosphatases↗