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Biomedical subjects

T Matoba

Publications and source records attributed to T Matoba.

At least 37 records · Page 2Linked to original sources
PubMed1990

Cardiovascular reflexes during vibration stress.

Vibration disease due to hand-held vibratory tools has various symptoms and signs which can be characterized by the severity. They include disorders of the central and autonomic nervous systems, as well as peripheral system disorders. The mechanism of Raynaud's phenomenon in vibration disease is proposed to be: Vibration and cold affect the local vessels and nerves directly, leading to enhanced release of chemical vasoconstrictors. Vibration, noise, cold, ergonomic and biodynamic conditions, and emotional stress during work result in disorders of the central and autonomic nervous systems. In the early stages, the autonomic nervous system may be stimulated, and in the later stages it is suppressed. When local vessel injuries and disorders of the central and local autonomic nervous mechanisms controlling the vessels occur, vasospasms in the fingers develop when the whole body is exposed to cold. The cardiovascular system, other than the peripheral circulatory system, may adapt to vibration stress. The adaptation subsides 7 to 8 years after discontinuation of the use of hand-held vibratory tools.

Cardiovascular System↗
PubMed1989

Responses of myocardial blood flows to whole-body vibration in the dog.

Experimentally acute exposure to whole-body vibration resulted in changes in myocardial blood flows in the in vivo dog. Regional myocardial blood flows measured by a hydrogen gas clearance method were increased at a vibration frequency of 120 Hz and decreased at 50 Hz. No appreciable changes were found in presence of a beta-adrenergic blocker. The values of plasma cyclic nucleotides were increased at both frequencies of vibration, more at 50 Hz than at 120 Hz. No significant changes were observed in heart rates and arterial pressure during and after vibration load. These findings suggest that increased myocardial blood flows in response to vibration may be related more to the frequency of vibration than to beta-adrenergic actions.

Animals↗
PubMed1989

Frequency dependence of the suppressive effects of vibration on atherosclerosis in the rabbit.

Whole-body vibration suppresses the development of atherosclerosis in the rabbit (Oki and Matoba, 1987). The present study was designed to clarify whether the effect of vibration on atherosclerosis depends on the frequency of vibration. Longitudinal vibrations at a frequency of 30 or 60 Hz was applied to 12 New Zealand white rabbits for 12 weeks. The gradual decrease in body weight and blood hematocrit in the vibration groups with time were parallel to the changes in the controls. The rate of increase in serum lipid concentrations induced by a cholesterol-rich diet was significantly suppressed in the vibration groups, as compared to the controls. This may be due to the vibration and not the diet. The aortic wall was thinner at 60 Hz than at 30 Hz, whereas the ratios of trace metals (Ca/Mg and Zn/Cu) in the aortic tissues were smaller at 30 Hz. The area of plaque formation in the intima was smaller at 60 Hz than at 30 Hz (p less than 0.05). Thus, the suppressive effect of vibration on the development of atherosclerosis in the aorta may be greater at a frequency of 60 Hz than at 30 Hz. Vibration may play an important role in lipid metabolism.

Animals↗
PubMed1987

Physiological methods used in Japan for the diagnosis of suspected hand-arm vibration syndrome.

In the pathogenesis of hand-arm vibration syndrome, vibration affects the peripheral system, especially the circulatory, nervous, and musculoskeletal systems. Medical questionnaires, physical examinations, and laboratory tests are used to diagnose the hand-arm vibration syndrome. The laboratory tests are satisfactory diagnostic aids for detecting slight disorders of the peripheral circulatory, nervous, and musculoskeletal systems. Peripheral circulatory function tests include skin temperature measured by a thermistor under specific temperature conditions, the nail compression test, and the cold provocation test (10-min immersion in cold water at 5 or 10 degrees C). To assess peripheral nervous function, tests for the pain and vibration senses are included. Peripheral musculoskeletal function tests consist of grip strength, pinch strength and tapping counts. These physiological tests are applied in worker screening twice a year. These tests have been authorized by the Ministry of Labour since 1973. Several criteria for the tests, although not authorized, are widely used. The diagnostic implication of each separate test may be low. Consequently, some laboratory tests should be evaluated, along with medical questionnaires and physical examinations, in the diagnosis of suspected hand-arm vibration syndrome.

Arm↗
PubMed1986

Comparable effects of oral diltiazem and verapamil in the treatment of hypertrophic cardiomyopathy. Double-blind crossover study.

The effects of oral diltiazem, 180 mg/day, were compared with those of oral verapamil, 240 mg/day, in 32 patients with hypertrophic cardiomyopathy (HCM), using a double-blind crossover study design. In the first treatment period, diltiazem and verapamil improved subjective complaints in 83% and 71% of those who were symptomatic in the baseline period. Maximal oxygen consumption on exercise stress test increased with verapamil by 2.9 +/- 4.2 ml/Kg/min (p less than 0.05), and tended to increase with diltiazem. Verapamil also reduced the amplitude of negative T wave. In the statistical analysis based on the crossover design, diltiazem and verapamil did not differ in global improvement, overall safety and global utility ratings. In addition, both drugs showed comparable effects on electrocardiographic and echocardiographic variables and exercise tolerance except for minor differences in diastolic blood pressure, T wave amplitude and peak exercise heart rate. On the other hand, verapamil tended to induce more serious side effects, forcing the discontinuation of medication in 3 patients. Therefore, the present study indicates that diltiazem is essentially equally as effective as verapamil and is preferable in the treatment of patients with HCM since it may exhibit fewer serious side effects.

Administration, Oral↗
PubMed1985

Body reactions during chain saw work.

Body reactions during chain saw work were studied in 14 subjects. The subjects divided into three groups (control, sulpiride, and propranolol) successively cut down logs with a chain saw for seven minutes. The start of the sawing led to a pronounced increase in heart rate which persisted during the sawing. The groups taking sulpiride and propranolol showed a smaller increase in heart rate compared with the controls. Hormonal values (adrenocorticotropic hormone (ACTH), cortisol, adrenaline (Ad), noradrenaline (NA), and dopamine) were increased by the operation. A comparison of these values before and after the operation showed that the increase of cortisol, Ad, and NA values was highest in the controls, intermediate in the propranolol group, and lowest in the sulpiride group. The increase in ACTH, however, was greatest in the sulpiride group, intermediate in the controls and correct in the propranolol group. These findings provide some evidence that chain saw work may have an influence on the whole body, including the hypothalamus and the limbic lobe of the brain.

Adrenocorticotropic Hormone↗
PubMed1985

Effects of diltiazem on occupational Raynaud's syndrome (vibration disease).

An open trial on the therapeutic effect of diltiazem, a calcium antagonist, was conducted on occupational Raynaud's syndrome (vibration disease). Seventeen men with vibration disease were studied. The mean age was 54 years. No patient had cardiovascular disease. Primary and secondary cases of Raynaud's phenomenon were excluded. Diltiazem, 30mg orally 3 times daily, was given to the patients for 6 weeks. Before and after this treatment period, we evaluated the subjective symptoms (11 items including Raynaud's phenomenon, numbness of hands and arms, stiffness of shoulder and neck, and others) and peripheral function (by cold water immersion test, vibration and pain sensations for fingers, tapping test, and momentary grasp strength test), and did laboratory blood tests (12 variables). The "effective" rates of subjective symptoms evaluating by the method of 5 steps and the peripheral function was 69.6% and 52.9%, respectively. The overall effectiveness of diltiazem therapy was assessed by collectively evaluating the changes in subjective symptoms, peripheral functions, and the occurrence of side effects. No side effects occurred during the treatment period. Thus, the collective effectiveness of diltiazem was 64.7%. In conclusion, diltiazem, a calcium antagonist, can be effective in long-term treatment of patients with vibration disease.

Benzazepines↗
PubMed1983

Increased left ventricular function as an adaptive response in vibration disease.

Vibration disease results from the long-term use of vibrating tools. Vibration, noise, and cold are stressors that impair the human body, inducing vibration disease. From echocardiographic methods, the left ventricular ejection fraction in vibration disease was 79 +/- 4%, a significantly higher value than that in control subjects (75 +/- 6%) (p less than 0.01). The increase in ejection fraction appeared to be due mainly to an increase in left ventricular end-diastolic dimension. The value of the ejection fraction was proportional to the activity of the autonomic nerves. The stroke volume index in patients with vibration disease was also significantly larger than that in the control subjects (p less than 0.001). Electrocardiograms revealed a significantly lower heart rate at rest and an increase in the ratio of T waves to R waves in precordial lead V6. These data suggest that the cardiovascular system in patients with vibration disease provides an adaptive response to the stressors.

Adaptation, Physiological↗
PubMed1983

Noninvasive assessment of the autonomic nervous tone in angina pectoris: an application of digital plethysmography with auditory stimuli.

To assess the relationship between autonomic nerve activity and the anginal attack, we examined the daily variation of the autonomic tones employing digital plethysmography with auditory stimuli, and also tested the daily variation of exercise capacity. Thirteen of 45 cases (28.9%) of spontaneous angina, excluding Prinzmetal's angina, complained of typical chest discomfort or pain especially in the morning. They manifested an augmented level of the autonomic nerve activity and positive stress testing. The remainder did not demonstrate these abnormal findings in the morning. For the 13 cases, calcium antagonists were given orally immediately after awakening. This resulted in the complete relief from chest discomfort or pain. These findings suggest that an autonomic imbalance plays an important role in the pathogenesis of this type of anginal attack. Thus, the estimation of the daily variation of autonomic nervous tone would be valuable for the diagnosis and treatment of angina pectoris.

Acoustic Stimulation↗