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Biomedical subjects

T Aihara

Publications and source records attributed to T Aihara.

At least 145 records · Page 8Linked to original sources
PubMed1986

Tortuous vertebral artery simulating extradural spinal tumour.

A rare case of cervical bone erosion resulting from pressure exerted by a congenital tortuous vertebral artery is presented with seven additional cases from the literature. The 3-4 level, especially on the left side, has been the most commonly affected site. The importance of the knowledge of this entity lies in the fact that it causes a surgically treatable radiculopathy, and also that this condition could easily be mistaken for a tumour, leading to accidental bleeding if carelessly approached.

Adult↗
PubMed1986

Ossification of the ligamentum flavum of the thoracic spine in adult kyphosis.

Ossification of the ligamentum flavum has been recognised as a definite clinical entity as is ossification of the posterior longitudinal ligament. The incidence of both is high in Japan. This study demonstrates that the incidence of ossification of the ligamentum flavum in persons who have a kyphosis of the thoracic or lumbar spine is higher than in those who do not. It is considered that localised mechanical stress affecting the ligamentum flavum is a contributing factor to the development of ossification, together with the generalised factors which may favour bone formation. However, the aetiology of this lesion is still obscure as is that of ossification of the posterior longitudinal ligament.

Adult↗
PubMed1986

[Indications for aortocoronary bypass operation in elderly patients: medical point of view].

Aorto-coronary (A-C) bypass operations were performed in 20 patients aged 68 to 78 years, and the indications for this operation were discussed retrospectively. The subjects consisted of 14 patients successfully operated and six patients unsuccessfully operated (death 3, graft occlusion 2, perioperative infarction 1). The results were as follows: Average age: There was no difference between the successful group (71.1 +/- 3.3 years; mean +/- SD) and the unsuccessful group (70.3 +/- 2.9 years). Coronary arteriographic findings: The average number of narrowed branches (greater than or equal to 75% stenosis) was 4.3 +/- 3.0 in the successful group (triple vessel disease in 12 cases and double vessel disease in four) and 2.7 +/- 0.5 in the unsuccessful group (triple vessel disease in four and double vessel disease in two), showing no significant difference between the two groups. Nine patients (64.3%) in the former group and one (16.7%) in the latter group had significant left main coronary artery disease (greater than or equal to 50% stenosis). Hemodynamic findings: Ejection fractions of less than 40% existed in three patients (50%) solely in the unsuccessful group; two of whom died. Left ventricular end-diastolic pressures of 30 mmHg or more existed in two cases (33.3%) only in the latter group. Other cardiac findings: Left ventricular end-diastolic dimension of 55 mm or more was found in one (7.1%) successful case and four (66.7%) unsuccessful cases. 201Tl-scintigrams showed a dilated left ventricular cavity in one case (7.1%) in the former group and two (33.3%) in the latter. Functions of other organs: Forced expiratory volume 1.0% or % vital capacity less than 70% was recognized in two cases (33.3%) only in the latter group. A level of serum creatinine more than 1.5 mg/dl was seen in only one case in the latter group. A case with advanced diabetes mellitus was present in the unsuccessful group, and this patient died of diabetic coma. A-C bypass operations are indicated for elderly patients when they have good cardiac function and have no complications of the kidneys, lungs and other organs. It is presumed that grafting the main coronary branches, thereby shortening the time of cardiopulmonary arrest prevents postoperative complications.

Aged↗
PubMed1985

Acoustic intensity histogram pattern diagnosis of liver diseases.

Display information on the histogram pattern includes echo intensity and echo frequency in the region of interest (ROI). The level and frequency of the center of gravity and the width of the echo level at 0%, 10%, and 50% of normalized frequency are calculated from the histogram. The width of the echo from the liver is significantly elongated on the X axis (P less than 0.001) but that of the center of gravity is not. Fatty liver shows the same attenuation rate curve as normal liver, although echo intensity is greatly increased. The curve of the attenuation rate derived from the histogram can be used to distinguish between liver cirrhosis and the tissue of normal or fatty liver. This study clearly demonstrates the clinical usefulness of the histogram as a diagnostic tool.

Carcinoma, Hepatocellular↗
PubMed1985

Morphology of ectopic ventricular beats and their relationship to ventricular tachycardia in acute myocardial ischemia.

The features of ventricular arrhythmia in coronary spasm induced by ergonovine were examined to elucidate the characteristics of ventricular arrhythmia in acute myocardial ischemia. The coupling intervals and configurations of the QRS wave of the premature ventricular beats (PVBs) were extremely variable, even in the same individual and at the closer time phases. The prematurity index (R-R'/QT) of PVBs with the right bundle branch block (RBBB) pattern was significantly smaller than with the left bundle branch block (LBBB) pattern. The vulnerability index (R-RX QT/R-R') of PVBs with the RBBB pattern was significantly larger than with the LBBB pattern. The incidence of PVBs with the RBBB pattern (50.4%) was slightly larger than with the LBBB pattern (40.5%). PVBs deteriorated into ventricular tachycardias (VTs) in 29 (24.8%) of 117 cases with the RBBB pattern and in 11 (11.7%) out of 94 cases with the LBBB pattern. Thus, PVBs with the RBBB pattern were more likely to progress to VT than with the LBBB pattern. But it is difficult to assess the clinical significance of PVBs from their QRS morphology alone, because 11 (27.5%) of 40 cases of VT were initiated by PVBs with the LBBB pattern.

Acute Disease↗
PubMed1985

[Some aspects of time-dose relationships].

One hundred thirty-seven patients with non-small cell lung cancers, 57 with oral cavity cancers and 98 with postoperative breast cancers treated with external radiotherapy from 1974 to 1980 were analyzed to determine optimal trends of time-dose relationships. Superiorities of fractionation factors were examined by comparing the relative local recurrence or expire rates among the subgroups prognostically homogenized in each entities of the diseases. Favorable fractionation factors for the former two diseases were those in which treatment was given in shortened over-all times, and frequently with low fraction dose to the considerably high daily dose. These results indicate the superiority of accelerated fractionation regime to conventional one in the treatment of those diseases. In contrast, any optimal trend was not found with postoperative breast cancers but total dose administered more than 43 Gy.

Breast Neoplasms↗
PubMed1984

Redundancy reducing processes in single neurons.

Interaction mechanisms between excitatory and inhibitory impulse sequences operating on neurons play an important role for the processing of information by the nervous system. For instance, the convergence of excitatory and inhibitory influences on retinal ganglion cells to form their receptive fields has been taken as an example for the process of neuronal sharpening by lateral inhibition. In order to analyze quantitatively the functional behavior of such a system, Shannon's entropy method for multiple access channels has been applied to biological two-inputs-one-output systems using the theoretical model developed by Tsukada et al. (1979). Here we give an extension of this procedure from the point of view to reduce redundancy of information in the input signal space of single neurons and attempt to obtain a new interpretation for the information processing of the system. The concept for the redundancy reducing mechanism in single neurons is examined and discussed for the following two processes. The first process is concerned with a signal space formed by superposing two random sequences on the input of a neuron. In this process, we introduce a coding technique to encode the inhibitory sequence by using the timing of the excitatory sequence, which is closely related to an encoding technique of multiple access channels with a correlated source (Marko, 1966, 1970, 1973; Slepian and Wolf, 1973) and which is an invariant transformation in the input signal space without changing the information contents of the input. The second process is concerned with a procedure of reducing redundant signals in the signal space mentioned before.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗