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Biomedical subjects

T Morimoto

Publications and source records attributed to T Morimoto.

At least 757 records · Page 42Linked to original sources
PubMed1982

Branching of muscle spindle afferents of jaw closing muscles in the cat.

1. Functionally isolated single fibres were prepared from the cut central ends of the masseter nerve in cats. Of those firing in response to muscle stretch, most were alpha motor units but some had the properties of afferent fibres innervating muscle receptors. 2. These afferent units were remarkably sensitive to muscle stretch even under anaesthesia deep enough to eliminate all stretch evoked e.m.g. activity in masseter. Moreover, these units responded to gentle pressing of the surface of either the masseter, temporalis or pterygoid muscles. 3. On the basis of their responses to ramp stretch, to high-frequency vibration, to suxamethonium, and to gentle pressing of the muscle surface, the majority were considered to arise from primary or secondary endings of muscle spindles. 4. In reflexly induced jaw movements, the highest discharge frequency of these spindles was observed during the jaw opening phase. However, they were also activated during the jaw closing phase, indicating that the fusimotor innervation to the source spindle was still preserved. 5. From these results, it is concluded that branching of the spindle afferent outside the capsule occurs in the muscle nerve innervating cat's jaw closing muscles.

Action Potentials↗
PubMed1982

A novel effect of salmon calcitonin on in vitro Ca-uptake by rat brain hypothalamus: the regional and hormonal specificities.

It was found that salmon calcitonin-I (sCT) inhibited in vitro 45Ca2+-uptake by rat brain hypothalamus blocks in a dose-dependent manner. The minimum effective concentration was estimated to be 10 nM or less. The effect appeared to be specific to the hypothalamus and was not observed with the pons plus medulla oblongata or the cerebral cortex. Two C-terminal fragments of the fish hormone, sCT (10-32) and sCT (22-32), and porcine calcitonin failed to inhibit the ion-uptake though tested in concentrations abolishing 125I-sCT binding to these brain tissues, indicating that the whole structure of sCT is essential for the inhibitory effect but not for the binding. Another finding to be noted was a possible dependency of this effect on the integrity of the cell membrane structure. A crude synaptosomal fraction subsequently prepared from sCT-exposed hypothalamus blocks exhibited a decreased uptake of 45Ca2+, while a corresponding fraction from unexposed tissue did not respond to the hormone. These characteristics of this novel in vitro effect of sCT suggest its possible relevancy to the anorectic effect which also appears to be specific to the fish hormone.

Animals↗
PubMed1982

Diameter spectra of sensory and motor fibers in nerves to jaw-closing and jaw-opening muscles in the cat.

The masseter and the mylohyoid nerves were examined using electron microscopy after unilateral destruction of the trigeminal motor nucleus by kainic acid injection in order to evaluate the distribution of sensory and motor fibers in masticatory muscle nerves. The surviving axons were counted and their diameters measured, and the results were compared with data for control nerves. The diameters of the control masseter nerves fibers were bimodally distributed with peaks at 2-5 and 7-9 micrometers. The nerve fiber diameters on the injected side, i.e., afferent fibers, also showed a bimodal distribution with peaks at 2-4 and 6-9 micrometers. On the other hand, the fiber diameter spectrum of the motor fibers, which was estimated from the loss of these fibers after kainic lesions, was unimodal within ranges of 1-16 micrometers. Consequently, the largest fibers of the masseter nerve were estimated to be motor fibers. A comparison of the distribution of diameters and conduction velocities of the afferent fibers indicates that both primary and secondary spindle afferents are mostly included in the larger diameter group with the peak at 6-9 micrometers. The diameters of fibers of the common mylohyoid nerve trunk showed a bimodal distribution, similarly to those of the masseter nerve. However, the analysis of the peripheral branches of the mylohyoid nerve revealed that the largest afferents in this nerve were of cutaneous origin, since muscle afferents of the anterior digastric and mylohyoid muscles have small diameters. These findings suggest that muscle spindles are absent or few in these two suprahyoid muscles in the cat.

Animals↗
PubMed1982

The modulation of murine immune responses by methyl-B12.

We examined the effect of methyl-B12 on the immune system. As a result, it was revealed that methyl-B12 enhanced antibody production in the in vitro system and that this activity was the strongest with methyl-B12 among the homologues of B12 examined, being nearly as strong as that of Levamisole. It was also revealed that methyl-B12 can exert an enhancing activity on the induction of suppressor T cells Con A. These facts suggest that methyl-B12 has a therapeutic effect against spontaneous incidence of diseases in NZA/W mice. These immunomodulative activities of methyl-B12 and their therapeutic significance against immune disorders were discussed.

Animals↗
PubMed1982

[Experimental studies of the effect of diltiazem (Ca-antagonist) on cerebral circulation and cerebral arterial spasm].

Polygraphycal studies were carried out in order to evaluate the effects of Diltiazem (Ca-antagonist) on cerebral circulation in cats. In addition to these studies, the inhibitory effect of Diltiazem on incubated blood-, and serotonin-induced vasocontraction of basilar arteries was observed through on operating microscope. Experimental vasospasm were induced by local administration of incubated blood and 10(-5)--10(-6) M serotonin solution. The required dose of Diltiazem, 30-300 micrograms/kg, was injected by one shot intravenously. CBF slightly decreased concomitantly with transiently decreased blood pressure shortly after intravenous injection of Diltiazem. After that, CBF increased for 15-20 minutes and returned to the state similar to that before the administration of Diltiazem. The changes in reactive pattern of CBF depend on the doses of Diltiazem and related to changes of CAR and VAR which were thought to indicate the blood of cardiac output. Vasocontraction induced by incubated blood and serotonin was released 30-35 per cent for 30 minutes after intravenous injection of Diltiazem 100 micrograms/kg. However, by administration of Diltiazem before and after local application of incubated blood and serotonin on basilar arteries, vasocontraction was inhibited completely. These data suggest that administration of Diltiazem (Ca-antagonist) might be useful in the prophylaxis and treatment of vasospasm following rupture of cerebral aneurysm.

Animals↗
PubMed1981

An evaluation of mass screening for breast cancer.

In Tokushima Prefecture, Japan, 41,922 women (26,669 in actual number) were subjected to mass screening with physical examination from 1970-1977. In 42 including 10 of so-called "interval cancer", breast cancer was detected. Those with breast cancer detected by mass screening were in the earlier stage of the disease as compared to those diagnosed through regular medical care at our-patient clinic during the same period. Procedures such as inspection and palpation are readily carried out and early occurrences of breast cancer can be detected.

Adult↗
PubMed1981

Killer cell (K-cell) population in chronic liver disease.

Peripheral blood killer cell (K-cell) population of patients with chronic hepatitis was investigated by means of a plaque-assay method using sheep red blood cells. The mean K-cell population of 14 control subjects was 5.1 +/- 2.0% (mean +/- SD), and that of 28 patients with chronic hepatitis was 4.4 +/- 3.1%. These 28 patients were divided into three groups: CPH, CAH 2A and CAH 2B. The mean K-cell population of each group was decreased in order of the severity of the disease. Especially, that of patients with CAH 2B was a statistically significant decrease (p less than 0.01) from control subjects. In the course most patients with CAH, K-cell population did not change for three months after admission. K-cell population was observed to decrease in the patients with active stage of liver cirrhosis, but not in patients with the terminal stage of liver cirrhosis, even in hepatoma patients. It is suggested that the K-cell population may play an important role of pathogenesis of chronic hepatitis.

Antibody-Dependent Cell Cytotoxicity↗