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Biomedical subjects

M Morioka

Publications and source records attributed to M Morioka.

At least 19 recordsLinked to original sources
PubMed1998

Serine/threonine phosphatase activity of calcineurin is inhibited by sodium orthovanadate and dithiothreitol reverses the inhibitory effect.

Orthovanadate is known to be an inhibitor of protein tyrosine phosphatases. However, we found that it inhibited calcineurin which has the activity of a serine/threonine protein phosphatase, using casein phosphorylated by cyclic AMP-dependent protein kinase as a substrate. Orthovanadate inhibits the Mn2+-activated activity of purified calcineurin to 20%; this is not the case without Mn2+. Furthermore, 10 mM dithiothreitol (DTT) reversed the inhibitory effects of orthovanadate. Orthovanadate showed the same inhibitory effect for calcineurin activity in homogenates as for the purified enzyme; the inhibitory effect was reversed by DTT. These results indicate that orthovanadate inhibits not only protein tyrosine phosphatases as reported, but also serine/threonine phosphatase activity of calcineurin.

Animals↗
PubMed1998

Cadherin-8 protein expression in gray matter structures and nerve fibers of the neonatal and adult mouse brain.

The topological distribution of mouse cadherin-8 protein in the neonatal and adult mouse brain was studied immunohistochemically using a rabbit antiserum. Cadherin-8 expression was restricted to several areas in neonatal brains constituting particular neural circuits, i.e. the limbic system, the basal ganglia-thalamocortical circuit, and the cerebellum and related nuclei. In addition, the nerve fibers linking some of the cadherin-8-positive areas, i.e. the habenulo-interpeduncular tract, decussation of the dorsal tegmentum, the medial longitudinal fasciculus, transverse pontine fibers, the brachium conjunctivum and the inferior cerebellar peduncle were cadherin-8 positive, as were the spinal tract of the trigeminal nerve, oculomotor nerve, facial nerve and trigeminal nerve. Cadherin-8 expression also showed a patch-like distribution in the intermediate gray layer of the superior colliculus, resembling acetylcholinesterase-rich patches in allocation. Segmentally organized cadherin-8-positive areas were found in the neonatal cerebellar Purkinje cell layer. Some nuclei and fibers in the brainstem and cerebellum, expressing cadherin-8 at neonatal stages, were also stained in the adult mouse brain. These findings suggest that cadherin-8 is involved in the formation of particular neural circuits by connecting areas expressing this molecule with positive nerve fibers, and indicate its possible implication in subdivisional organization in the superior colliculus and cerebellum.

Animals↗
PubMed1998

Nonfunctioning adrenal cortical cancer and analysis of the steroidogenic activity of the tumor: a case report.

An adrenocortical cancer was detected by a CT scan in a 37-year-old woman, which did not have an excessive secretion of steroids or catecholamines. The tumor was enhanced inhomogeneously by the bolus injection of contrast medium, and magnetic resonance imaging (MRI) showed that the tumor was hypointense compared to the liver on a T1-weighted image and was diffusely hyperintense on a T2-weighted image. Histologically, the tumor consisted predominantly of compact cells with marked cellular and nuclear pleomorphism, but no capsular or vascular invasion were observed. An analysis of the steroidogenic activity of the tumor revealed that the activity of mitochondrial P450c11beta was extremely reduced in the tumor.

Adrenal Cortex Neoplasms↗
PubMed1998

Experimental studies of subjective response to road traffic-induced building vibration.

The road traffic-induced building vibration was recorded continuously for 24 hr in three orthogonal axes outside and inside the building. Several alternative objective methods of quantifying the severity of exposures to whole-body road traffic-induced building vibration are used. The relationship between the results of all objective evaluation methods of vibration-induced by road traffic and the subjective responses to building vibration are compared. It was conducted that the ISO 2631-2 z-axis frequency weighting combined with a measure of vibration dose value (VDV = [integral of a4(t) dt)]1/4 may use a practicable objective evaluation procedure in buildings than L10 percentile vibration levels. It was also cleared that the L10 percentile vibration levels at the ground boundary of the regulation law of Japan Environmental Agency must be low levels.

Building Codes↗
PubMed1998

Measurement of hand-transmitted vibration of tapping the long cane for visually handicapped people in Japan.

The long cane can be used as a mobility aid for visually handicapped people. According to a questionnaire completed by Japanese cane users, it seems they are not always satisfied with using long canes for a variety of reasons. In this study, hand-transmitted vibration from the long cane due to tapping the ground was measured because an exposure to repeated shock-type tapping vibration may affect the hand-arm system. A sighted female wearing a blindfold participated. The measurement was carried out in different conditions with three different ground materials both indoor and outdoors. The vibration at three axes of the cane grip and one axis at the wrist were measured. The pinch forces between an index finger and the grip were also measured using a strain gauge in order to observe how the vibration characteristics depend on the changing forces. Measurement, evaluation and assessment were based on the International Standard (ISO 5349). The estimated daily exposure time and the transmissibility were obtained in order to investigate the severity of the hand-transmitted vibration caused by the long cane. It was found that the characteristics of tapping vibration depend on different measurement conditions and the vibration might be associated with a health risk over a long life span.

Adult↗
PubMed1998

Prediction of TTS for hand intermittent vibration.

Temporary Threshold Shift (TTS) is often used as an indicator of the effect of hand-transmitted vibration on the human body. An experiment for the prediction of TTS in exposure to intermittent vibration was conducted in the present study to examine the exposure equivalent rule, as well as the equations for growth and recovery TTS. It was found that the prediction of TTS obtained here was in good agreement with measured TTS. This estimation procedure for predicting TTS was compared with the notification of the Labor Ministry in Japan, in which control of the operation time and the rest time for hand-vibrating tools was described. The results suggest that the rest time of five minutes for a continuous exposure time of 30 minutes with low-level of vibration tools should be extended to 10 minutes of rest time.

Adult↗
PubMed1998

Pathophysiology and treatment of cerebral ischemia.

This article describes the pathophysiology of, and treatment strategy for, cerebral ischemia. It is useful to think of an ischemic lesion as a densely ischemic core surrounded by better perfused "penumbra" tissue that is silent electrically but remains viable. Reperfusion plays an important role in the pathophysiology of cerebral ischemia. Magnetic resonance imaging (MRI) and histological studies in rat focal ischemia models using transient middle cerebral artery (MCA) occlusion indicate that reperfusion after an ischemic episode of 2- to 3-hour duration does not result in reduction of the size of the infarct. Brief occlusion of the MCA produces a characteristic, cell-type specific injury in the striatum where medium-sized spinous projection neurons are selectively lost; this injury is accompanied by gliosis. Transient forebrain ischemia leads to delayed death of the CA1 neurons in the hippocampus. Immunohistochemical and biochemical investigations of Ca2+/calmodulin-dependent protein kinase II(CaM kinase II) and protein phosphatase (calcineurin) after transient forebrain ischemia demonstrated that the activity of CaM kinase II was decreased in the CA1 region of the hippocampus early (6-12 hours) after ischemia. However, calcineurin was preserved in the CA1 region until 1.5 days after the ischemic insult and then lost; a subsequent increase in the morphological degeneration of neurons was observed. We hypothesized that an imbalance of Ca2+/calmodulin dependent protein phosphorylation-dephosphorylation may be involved in delayed neuronal death after ischemia. In the treatment of acute ischemic stroke, immediate recanalization of the occluded artery, using systemic or local thrombolysis, is optimal for restoring the blood flow and rescuing the ischemic brain from complete infarction. However, the window of therapeutic effectiveness is very narrow. The development of effective neuroprotection methods and the establishment of reliable imaging modalities for an early and accurate diagnosis of the extent and degree of the ischemia are imperative.

Adaptation, Physiological↗
PubMed1997

Calcineurin in the adult rat hippocampus: different distribution in CA1 and CA3 subfields.

We examined the immunohistochemical regional distribution of calcineurin (Ca2+/calmodulin-dependent protein phosphatase) in the adult rat hippocampus, following various regional destruction. In the normal adult rat hippocampus, the calcineurin immunoreactivity showed a characteristic pattern. This protein phosphatase was detected in all layers of the CA1 subfield, including the cytoplasm of the pyramidal cells, whereas it was strongly evident in the stratum lucidum and moderately so in the cytoplasm of pyramidal cells in the CA3 subfield. Seven days after transient forebrain ischemia, which induced destruction of CA1 pyramidal cells, the calcineurin immunoreactivity decreased in all layers of the CA1 subfield, while the immunoreactivity for synapsin I, a marker of the presynaptic site, was preserved. Seven days after the intraventricular injection of kainate, which induced destruction of CA3 pyramidal cells, the calcineurin immunoreactivity in the stratum lucidum was preserved, although the immunostaining pattern of the stratum lucidum changed when CA3 pyramidal cells were destroyed. Seven days after mechanical destruction of the dentate gyrus and CA4 subfield, which induced destruction of mossy fibers, the calcineurin immunoreactivity in the stratum lucidum was lost, except in the far site of the stratum lucidum. In the CA1 subfield, calcineurin was mainly located in postsynaptic sites, while it was mainly located in the presynaptic sites in the mossy fibers of the CA3 subfield. The immunohistochemistry of adjacent sections with antibodies of microtubule-associated protein 2 and synapsin I, which are markers of postsynaptic and presynaptic sites respectively, supports these results. Thus, calcineurin has a different synaptical distribution in the rat hippocampus.

Animals↗
PubMed1997

Ruptured distal accessory anterior cerebral artery aneurysm: case report.

OBJECTIVE AND IMPORTANCE: Accessory anterior cerebral artery (ACA), which is a type of median artery of anomalous triplicate ACA, is not rare, but aneurysmal formation is extremely rare. We report a rare case with ruptured aneurysm arising from a distal accessory ACA. We discuss the characteristics and causes of this type of aneurysm and classification of this anomaly. CLINICAL PRESENTATION: A 63-year-old man suddenly developed severe headache and then loss of consciousness and paraplegia. Computed tomography disclosed thick and diffuse subarachnoid hemorrhage and interhemispheric hematoma. Subsequent bleeding occurred 2 hours after the first hemorrhage. Cerebral angiography disclosed a saccular aneurysm arising from the distal accessory ACA. INTERVENTION: Neck clipping of the aneurysm was performed 22 hours after the second episode, using an interhemispheric approach. CONCLUSION: Although transient paraplegia occurred 8 days after onset, the patient recovered well after surgery without neurological deficit. The characteristics of the aneurysm arising from distal accessory ACA are considered similar to those of distal ACA aneurysm. There is, however, some confusion regarding the terminology of the anterior communicating artery complex anomalies, which we discuss.

Aneurysm, Ruptured↗
PubMed1997

A rare case of Cushing's syndrome due to bilateral adrenocortical adenomas.

We report a rare case of Cushing's syndrome due to bilateral adrenocortical adenomas in a 45-year-old female. She suffered from diabetes mellitus and hypertension for a decade, but her appearance was not Cushingoid. The plasma cortisol level in the morning was at the upper limit of the normal range, but did not show a diurnal rhythm or was suppressed by 1 mg of dexamethasone. The plasma level of ACTH was undetectable, and it failed to respond to human CRH (hCRH). Plasma cortisol responded well to synthetic ACTH. The urinary 17-OHCS level was high, and was not suppressed by 4 mg of dexamethasone. While these findings were consistent with a diagnosis of adrenocortical adenoma, computed tomography showed several nodules in both adrenal glands that suggested the presence of huge nodular adrenocortical hyperplasia or bilateral adrenocortical adenomas. Bilateral adrenalectomy demonstrated the presence of three adenomas, two in the right and one in the left adrenal. Analysis of the extract from each adenoma revealed that two of the three produced an excess amount of cortisol. Magnetic resonance imaging (MRI) of the brain suggested the presence of pituitary adenoma. Prior to adrenalectomy, TSH, GH or LH showed a low response to TRH, GHRH or LHRH, respectively. Since normal responses were restored after bilateral adrenalectomy, these abnormalities were attributed to hypercortisolemia.

Adrenal Cortex Neoplasms↗
PubMed1997

Aldosterone-producing adrenal cortical cancer: a case report and analysis of steroidogenic enzymes in the tumor.

A case of hyperaldosteronism caused by adrenal cortical cancer observed in a 32-year-old man was reported. The patient showed marked hypertension and hypokalemia, but neither obesity nor hyperglycemia was observed. Endocrine studies revealed hyperaldosteronism and concurrent excessive secretion of cortisol, but diurnal rhythms of plasma ACTH and cortisol were normal. Imaging studies revealed a large left adrenal mass, and the positive accumulation of radiolabelled material by adrenal scintigraphy was observed both in the tumor and the contralateral adrenal gland. The removed tumor was predominantly composed of dark compact cells with marked nuclear pleomorphism, and mitotic figures and sinusoidal invasion were also observed. The analysis of steroidogenic enzyme activities revealed that the activity of aldosterone-synthesizing enzyme (P-450aldo) which was usually undetectable in normal adrenal tissues and adenomas other than aldosterone-producing adenoma (APA) was detectable as one-third of that of APA. Although activities of other enzymes were reduced, the expression of P-450aldo activity was considered to be the specific character of this cancer.

Adrenal Cortex Neoplasms↗
PubMed1997

The analysis of steroidogenic activity in non-hyperfunctioning adrenocortical adenoma.

The steroidogenic activities in non-hyperfunctioning adrenal adenoma (NHFA) have not yet been fully examined. Steroid content both in adenoma and its non-tumorous adjacent adrenal tissue was measured by the HPLC system in 8 cases of NHFA and 2 cases of preclinical Cushing's syndrome (PCS). Activities of cytochrome P450c17alpha, P450c21, P450c11beta, P450c18 and aldosterone-synthesizing enzyme (P450aldo) were also determined by the enzyme reconstitution system. Steroid content in NHFA varied but no significant difference was seen between NHFA and normal control adrenals. Activities of all P450s except P450aldo were confirmed in NHFA, but they were almost equivalent to those in normal control adrenals. As no significant difference between NHFA and normal controls was observed in either steroid contents or P450s activities, the steroidogenic activity of NHFA is considered to be comparable to that of normal adrenals.

Adenoma↗
PubMed1997

ACTH-independent macronodular adrenocortical hyperplasia (AIMAH): report of two cases and the analysis of steroidogenic activity in adrenal nodules.

We report clinical findings and steroidogenic activities in adrenal tissues in 2 cases of AIMAH. Endocrine studies revealed an undetectable level of plasma ACTH and a diminished circadian rhythm of plasma cortisol. A significant increase in plasma cortisol levels in response to ACTH stimulation was observed in both cases. After the administration of metyrapone in one case, urinary excretion of 17-hydroxycorticosteroid (17-OHCS) significantly increased, although the plasma ACTH level did not respond. Computed tomography showed large masses in both adrenal glands, and bilateral uptake was identified on adrenal scintigraphy. The totals for the bilateral adrenal glands were 98 g and 105 g, respectively, and the left adrenal was larger than the right in both cases. Steroid content in the nodules measured by high performance liquid chromatography (HPLC) showed that the cortisol content was definitely lower than that in cortisol-producing adenoma (CPA) and even in normal adrenals. The activities of cytochrome P450c17, P450c21 and P450c11 were evaluated in one case, and all of them were reduced in the nodules. Especially that of P450c17 was remarkably reduced. These data suggest that cortisol production in AIMAH is inefficient, and that the cause of Cushing's syndrome may be related to the marked increase in the number of cells or bulk of the tumor.

17-Hydroxycorticosteroids↗
PubMed1997

A comparison of vibrotactile thresholds on the finger obtained with ISO type equipment and Japanese equipment.

A vibrotactile threshold measurement system that enables the thresholds at the fingertips to be determined more rapidly and precisely has been developed. This system was studied to assess the impact of various factors on the obtained values. An experiment using two different types of equipment was also conducted to assess the repeatability of measurement. One system was similar to that required by International Standard (System A), and the other system was of the currently used in Japan (System B). The subjects were nine males and one female, measurements were taken on three different days. This paper compares the structure of the equipment used internationally (ISO/CD13091) and the equipment typically used in Japan and the measurements of vibrotactile thresholds taken at a 125 Hz frequency using Systems A and B. The measurement method and conditions adopted were almost the same as those outlined in the ISO draft. The results of this experiment showed that there were some differences between the two systems. The vibrotactile thresholds measured using System B showed higher values than did those measured using System A. The results also indicated that equipment that satisfies ISO standards provides sufficient repeatability for use as a diagnostic aid. Also, this paper is shown the vibrotactile measurement equipment conditions must be considered when using vibrotactile threshold measurement equipment in Japan.

Durable Medical Equipment↗
PubMed1997

YM-32890 A and B, new types of macrolide antibiotics produced by Cytophaga sp.

Two new types of macrolide antibiotics, YM-32890 A and B, have been isolated from the fermentation broth of cytophaga sp. YL-02905S. In this paper, the taxonomy of the producing strain, fermentation, isolation, structure elucidation, and biological activity of the antibiotics are reported. YM-32890 A inhibits the growth of staphylococci including a macrolide-resistant strain, but shows no antimicrobial activity against other Gram-positive, Gram-negative bacteria and yeast.

Anti-Bacterial Agents↗
PubMed1997

[Anesthetic managements for pericardiectomy of three patients with constrictive pericarditis].

We experienced three patients with constrictive pericarditis who underwent pericardiectomy. Percutaneous cardiopulmonary support (PCPS) was carried out in two patients because of unstable hemodynamics caused by massive bleeding or cardiac compression due to surgical manipulation. In the other patient with severe tachycardia, we prepared PCPS before the induction of anesthesia, and could manage the whole course of anesthesia satisfactorily. It is suggested that PCPS is the most reliable way to support hemodynamics during anesthesia in patients with constrictive pericarditis.

Anesthesia↗