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Biomedical subjects

H Miyata

Publications and source records attributed to H Miyata.

At least 361 records · Page 20Linked to original sources
PubMed1988

[Effects of ulinastatin on experimental arthritis].

Effects of the urinary enzyme inhibitor ulinastatin on experimental arthritis were investigated. Ulinastatin at the dose of 30,000 units/kg/day, i.v., significantly restored the swelling of hind paw, inflammatory score and bone damage in adjuvant arthritic rats. Intraarticular administration of ulinastatin at 3000 units/site x 3, significantly suppressed the articular swelling and the elevated inflammatory parameters in the synovial fluid of carrageenin-induced arthritic rabbits. Moreover, ulinastatin at the dose of 50000 units/kg/day, i.v., significantly prevented the elevation of serum rheumatoid factor and articular lesions in MRL/l mice. In addition, ulinastatin significantly inhibited human granulocyte elastase and cathepsin G. These findings indicate that ulinastatin may be a useful therapeutic agent for arthritis.

Animals↗
PubMed1988

[The effects of eicosapentaenoic acid ethyl ester (EPA-E) on arterial thrombosis in rabbits and vascular lesions in rats].

The effects of highly purified ethyl ester of eicosapentaenoic acid (EPA-E) on ellagic acid-induced thrombus formation in the stenosed femoral artery in rabbits and on the progression of laurate-induced vascular lesions in rats were examined. (1) EPA-E in single administration significantly prevented the thrombus formation induced by ellagic acid in the stenosed femoral artery of rabbits. (2) EPA-E restored the hypercoagulation activity at 5 min and 3 hr after the ellagic acid injection. Platelet aggregability induced by arachidonic acid decreased at 5 min and 3 hr after the ellagic acid injection; EPA-E had little effect on this change. EPA-E showed almost no effect on fibrinolytic activity, blood viscosity and filterability of washed red blood cells after the ellagic acid injection. (3) Moreover, EPA-E in daily administrations showed a significant preventative effect against the laurate-induced vascular lesions in rats. The efficacy of EPA-E on arterial thrombosis and vascular lesions observed in this study suggests that EPA-E is a candidate for the treatment of peripheral circulatory disturbance.

Animals↗
PubMed1988

Temporal bone findings in cloverleaf skull syndrome.

Cloverleaf skull syndrome was first reported in 1960 by Holtermüller & Wiedemann as Kleeblattschädel-Syndrome. The case in the present report was that of a male infant 26 days old at the time of death. Besides a trilobed skull and abnormalities of the extremities, he had low-set ears, stenosis of both external auditory canals, a beak-like nose, microphthalmia, retentio testis and congenital dermal sinus-like anomaly at the coccygeal region. A chromosome study revealed a normal male karyotype. The right temporal bone showed some anomalies through the external and middle ears. The bony portion of the external auditory canal was narrowed. The middle ear cavity was filled by mesenchymal tissue devoid of cell components. The incus was almost attached to the lateral tympanic wall. In addition, the stapes was thickened and bent anteriorly. The sensory and neutral elements of the inner ear were normal.

Craniosynostoses↗
PubMed1987

Post-natal development of the retinal and cerebellar projections onto the lateral suprasylvian area in the cat.

1. Post-natal development of the retinal and cerebellar projections onto the medial bank of the lateral suprasylvian visual area was examined by using the field potential method and, additionally, by the orthograde horseradish peroxidase method. 2. Optic nerve stimulation elicited a surface-positive, depth-negative field potential in the medial bank of the lateral suprasylvian area of adult cats. By contrast, in kittens younger than 3 weeks old, a surface-negative, depth-positive field potential was evoked. The response grew adult-like by 1 month of age. Corticocortical response, activated by stimulation of cortical areas 17 and 18, underwent a similar developmental change. 3. Cerebellar stimulation evoked a surface-negative, depth-positive wave from birth up to adulthood. Thalamocortical afferents from the ventroanterior and ventrolateral nuclei of the thalamus to the medial bank of the lateral suprasylvian area, which is presumed to be responsible for this cerebellar response, terminate mostly in layer I in both new-born kittens and adult cats. 4. The present results, and our previous morphological findings on the projections from the extrageniculate visual thalamus and visual cortical areas 17 and 18 onto the medial bank of the lateral suprasylvian area, were correlated with reference to the maturation of the neuronal circuit in the cortex.

Aging↗
PubMed1987

Modulation of actomyosin ATPase by thin filament-associated proteins.

Phosphorylation of the myosin light chain is a prerequisite for actin-activation of the Mg-ATPase of smooth muscle myosin. However, maximal activation of the Mg-ATPase by actin requires stoichiometric binding of tropomyosin to actin filaments and Ca2+ at free Mg2+ below 3 mM. The requirement for Ca2+ for actin-activation is not due to a calcium-mediated binding of tropomyosin to actin since the binding of tropomyosin to actin is not dependent on Ca2+. Caldesmon, an actin and calmodulin binding protein, at caldesmon:actin molar ratio of 1:18, binds equally to pure actin and actin containing stoichiometric amounts of bound tropomyosin. The Mg-ATPase of myosin reconstituted with actin is not affected by the caldesmon; on the other hand, the activity of actomyosin containing tropomyosin is inhibited. The inhibition of activity by the caldesmon is reversed by the addition of calmodulin (caldesmon:calmodulin molar ratio, 1:8) in the presence of Ca2+. The amount of caldesmon bound to actin in the presence of calcium-calmodulin is 50% more when actin filaments contain tropomyosin, indicating that the release of inhibition of the activity inhibited by caldesmon does not require complete release of caldesmon from actin.

Actins↗
PubMed1986

Postnatal development of afferent projections to the lateral suprasylvian visual area in the cat: an HRP study.

The postnatal development of thalamic and cortical projections to the medial bank of the lateral suprasylvian area was studied in the cat by using the retrograde and orthograde HRP methods. Both projections are already present at birth. In both newborn kittens and adult cats, the thalamic projections arise from the same nuclei. By far the heaviest thalamic projection originates from a relatively lateral portion of the lateral posterior nucleus (the presumed LPl). The cortical laminar distribution of the afferents arising from the presumed LPl changes markedly with aging. In kittens younger than 1 week, the terminals are distributed densely in layer I and sparsely in layer IV. With age, the terminals in layer I become less dense while those in layer IV become denser. By 1 month of age, the terminal distribution is similar to that found in adult cats, in which the terminals are sparse in layer I and dense in depth--particularly, in layer IV. The terminal distribution of the corticocortical projections from areas 17 and 18 also changes with aging. The terminals in kittens younger than 2 weeks are distributed in both superficial and deep cortical layers, whereas those in kittens older than 1 month and in an adult cat are distributed only in deep layers.

Animals↗
PubMed1986

Modulation of smooth muscle actomyosin ATPase by thin filament associated proteins.

Caldesmon binds equally to both gizzard actin and actin containing stoichiometric amounts of bound tropomyosin. The binding of caldesmon to actin inhibits the actin-activation of the Mg-ATPase activity of phosphorylated myosin only when the actin contains bound tropomyosin. The reversal of this inhibition requires Ca2+-calmodulin; but it occurs without complete release of bound caldesmon. Although phosphorylation of the caldesmon occurs during the ATPase assay, a direct correlation between caldesmon phosphorylation and the release of the inhibited actomyosin ATPase is not consistently observed.

Actins↗
PubMed1986

Role of tropomyosin in smooth muscle contraction: effect of tropomyosin binding to actin on actin activation of myosin ATPase.

The binding of gizzard tropomyosin to gizzard F-actin is highly dependent on free Mg2+ concentration. At 2 mM free Mg2+, a concentration at which actin-activated ATPase activity was shown to be Ca2+ sensitive, a molar ratio of 1:3 (tropomyosin:actin monomer) is required to saturate the F-actin with tropomyosin to the stoichiometric ratio of 1 mol of tropomyosin to 7 mol of actin monomer. Increasing the Mg2+ could decrease the amount of tropomyosin required for saturating the F-actin filament to the stoichiometric level. Analysis of the binding of smooth muscle tropomyosin to smooth muscle actin by the use of Scatchard plots indicates that the binding exhibits strong positive cooperativity at all Mg2+ concentrations. Calcium has no effect on the binding of tropomyosin to actin, irrespective of the free Mg2+ concentration. However, maximal activation of the smooth muscle actomyosin ATPase in low free Mg2+ requires the presence of Ca2+ and stoichiometric binding of tropomyosin to actin. The lack of effect of Ca2+ on the binding of tropomyosin to actin shows that the activation of actomyosin ATPase by Ca2+ in the presence of tropomyosin is not due to a calcium-mediated binding of tropomyosin to actin.

Actins↗
PubMed1986

Regeneration of the cerebellofugal projection after transection of the superior cerebellar peduncle in kittens: morphological and electrophysiological studies.

In contrast to the current concept of abortive regeneration of mammalian central axons, occurrence of marked, functionally active regeneration of the cerebellofugal projection was proved in kittens after complete transection of the decussation of the brachium conjunctivum (BCX). By means of the anterograde axonal transport of horseradish peroxidase that was injected into the cerebellar lateral and interpositus nuclei, the origin, course, and destination of the regenerated fibers were identified unambiguously and the time-course of axonal regeneration was clarified. Functional connectivity of the regenerated cerebellothalamic projection was tested electrophysiologically. In eight out 82 animals, marked regeneration of the cerebellofugal projection occurred; in the majority of the rest of the animals, trace amounts of regenerated fibers were observed. In the former but not in the latter animals, marked cerebellocerebral responses, as in intact animals, were evoked in the frontal motor and parietal association cortices. Most of the regenerated axons took a course similar to that of the normal projection and terminated in the normal projection areas, whereas a small proportion of fibers showed an aberrant course and termination. The cut ends of axons began to swell as early as 15 minutes after transection, and the regenerated axons produced dense terminals in the thalamus by 19 days.

Aging↗
PubMed1986

Transfer function of right- and leftward eye movements in patients with unilateral labyrinth.

In patients with loss of unilateral labyrinthine function, the dynamic characteristics of rightward eye movement and leftward eye movement induced by the healthy labyrinth were displayed respectively. In patients who were examined within a few months after loss of unilateral labyrinthine function, the gain of eye movement toward the healthy labyrinth was low compared with that of eye movement toward the opposite direction. These differences in the gain were remarkable in the frequency range from 0.01 to 0.1 Hz. But those differences in the gain were not detected in patients who were examined more than 3 months after loss of unilateral labyrinthine function.

Adult↗