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Biomedical subjects

T Morimoto

Publications and source records attributed to T Morimoto.

At least 793 records · Page 44Linked to original sources
PubMed1980

The effect of maximal mouth opening on dimension discrimination.

The ability of twenty-five young persons to discriminate dimensions was tested. A reference stick of 10 mm was placed between the teeth, alternating with test sticks of different heights. After application of the reference stick the subjects were asked to open the mouth maximally. A test stick was placed on the lower incisors and the subjects closed the mouth slowly, until their upper incisors contacted the test stick. The subjects were then asked to assess whether a test stick felt higher or lower than the reference stick. Using this experimental method, it was found that incorrect assessments were symmetrically distributed around the 10 mm reference stick. A receptor mechanism is proposed, and applied to explain the results of the present and a previous experiment.

Humans↗
PubMed1980

Fusimotor activity in masseter nerve of the cat during reflex jaw movements.

1. Unit recordings have been made from the central ends of filaments of the masseter nerve in lightly anaesthetized cats. Evidence is presented to show that fusimotor activity may be distinguished from alpha motor activity. 2. During reflex cyclic movements induced by intra-oral stimulation, two distinct patterns of fusimotor firing emerged. One type of unit increased firing at the beginning and sustained this with little modulation throughout the movements. The other type was strongly modulated approximately in parallel with the alpha motor activity. 3. By comparison with records of jaw elevator spindle afferents under similar conditions, it was deduced that the sustained type of action was due to dynamic fusimotor neurones while the modulated type was due to static fusimotor neurones. 4. The patterns of fusimotor activity seen in these rhythmic movements under light anaesthesia agree well with the patterns deduced from spindle recordings in the conscious cat during mastication. 5. The results emphasize the importance of looking beyond a simple hypothesis of 'alpha-gamma co-activation' to explain fusimotor function. It is proposed that tonic dynamic fusimotor activity is set at the beginning of a movement to determine the incremental sensitivity of primary endings to stretch. The static fusimotor fibres are activated principally during shortening to help keep both primary and secondary endings active.

Animals↗
PubMed1979

In vitro synthesis of the Ca2+ transport ATPase by ribosomes bound to sarcoplasmic reticulum membranes.

The calcium transport ATPase (M(r) 100,000) from sarcoplasmic reticulum membranes was synthesized in a cell-free translation system containing rough microsomes or detergent-treated bound polysomes from 14- to 16-day old chicken embryo muscles. Immunoprecipitates obtained from total translation mixtures treated with anti-ATPase antiserum contained 1.5% of the total radioactivity incorporated in vitro. A polypeptide with the electrophoretic mobility, isoelectric point, and [(35)S]methionine-labeled tryptic peptide pattern of the mature ATPase was a major component of these immunoprecipitates. By contrast, free polysomes from the same source, which were capable of high levels of in vitro protein synthesis, did not yield immunoprecipitable ATPase. ATPase synthesized in rough microsomes was not released by treatment with 10 mM EDTA in a high-salt medium (0.5 M KCl) which removes ribosomes and peripheral membrane proteins. Furthermore, labeled ATPase remained associated with the microsomes after these were treated with low concentrations of deoxycholate (0.1 mg/mg of protein in 0.3 ml) which release the luminal content of the vesicles. Only with higher deoxycholate concentrations (0.5 mg/mg of protein in 0.3 ml), which cause membrane dissolution, was the labeled ATPase found on the detergent extracts. These observations indicate that newly synthesized ATPase discharged from bound ribosomes is transferred directly to the sarcoplasmic reticulum membranes where it is incorporated as an integral membrane protein.

Animals↗
PubMed1979

Effects of the interpolated vibratory stimulation on the interdental dimension discrimination in normal and joint defect subjects.

No significant differences in the interdental dimension discrimination (IDD) ability were found between normal and joint defect subjects. Furthermore, vibration onto the mandible gave similar effects on the nature of IDD in both subject groups. Thus, the muscle spindles of masticatory muscles may contribute to IDD, but temporomandibular receptors may not.

Adolescent↗
PubMed1979

Intracellular pH measurement in frog muscle by means of 31P-nuclear magnetic resonance.

The 31P-NMR technique was used for the monitoring of intracellular pH and studying its heterogeneity in the femoral biceps muscle of Rana catesbiana under anaerobic conditions. The value of intracellular pH of fresh muscle calculated from the chemical shift of intracellular inorganic phosphate (P1) was 7.3 on average and the line width of P1 was about 0.2 ppm. As the line width determined by the relaxation mechanism was 0.099 ppm, the P1 signal in fresh muscle was concluded to consist of overlapped narrow components, which indicated the heterogeneity of muscular pH (about 0.2 pH unit). Living muscle showed gradual acidification due to glycolysis and the decrease in heterogeneity. When glycolysis was suppressed by iodoacetic acid, slight alkalization due to the breakdown of creatine phosphate was observed. When the Lohmann reaction was suppressed by 2, 4-dinitro-1-fluorobenzene, rapid acidification accompanied by the appearance of a new acidic component was observed with the onset of ATP decrease. This new component was not detected in the muscle pretreated with glycerol to disrupt the transverse tubules. Therefore, it is likely that this new acidic component originates in the intracellular compartment, and not in the cellular difference.

Animals↗
PubMed1979

Effect of exercise and thermal stress on subcutaneous protein transport.

Radioiodinated albumin was injected into the subcutaneous tissue of the thigh of human subjects and its disappearance rate from the injection site and the blood levels of the tracer were compared between exercise loaded, heat loaded experiments and the control utilizing two-compartment analysis. The time course of radioactivity in the blood was expressed as the equation p(t) = A(e-alpha t - e-beta t). In the exercise experiment, the half-time of beta and the time required to reach the maximum level was significantly shorter than in the heat experiment and in the controls. The decay of radioactivity at the injection site was set to the equation s(t) = Be-gamma t + Ce-delta t by the least square method. The value of gamma, which had a half-time of about 24 hr, was significantly shorter in the exercise than in the control experiments. From these results, it was concluded that the rate of mobilization of subcutaneous protein via lymph flow is faster under an exercise load than the control, and that the rate under heat load does not deviate from control experiments.

Adult↗
PubMed1978

Blood volume and plasma constituent changes in splenectomized dogs consequent to exercise.

To assess the effects of submaximal exercise on fluid balance and blood constituents, changes in plasma volume, hematocrit, hemoglobin, plasma protein, serum osmolality, and serum electrolytes were measured in splenectomized dogs during treadmill work and recovery. During exercise approximating 32 and 50% of Vo2max, plasma volume did not significantly change. During recovery, plasma volume tended to increase by the same amount at both levels of exercise. Both total circulating plasma protein content and protein concentration increased during exercise. Serum osmolality increased abruptly during exercise and returned to the pre-exercise level immediately after cessation of work. Plasma volume changes calculated from both hematocrit and hemoglobin concentrations correlated well with direct measurements using labelled erythrocytes, but values calculated from hematocrit alone averaged 12% higher.

Animals↗