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Biomedical subjects

M Shibuya

Publications and source records attributed to M Shibuya.

At least 379 records · Page 21Linked to original sources
PubMed1988

A serrated suction tip for tumor removal. Technical note.

A serrated suction tip with a variety of diameters and serrations has been developed for the microsurgical removal of tumors. These tips can dissect and aspirate tumor tissue, cerebrospinal fluid, or blood simultaneously, and the degree of suction can be controlled by the pressure of the tip against the tumor.

Equipment Design↗
PubMed1988

[Changes in monoamine neurotransmitter metabolism in brain ischemia measured by in vivo voltammetry].

A preliminary work with in vivo voltammetry (IVV) in the ischemic brain had been performed by the authors in rats after cardiac arrest, which showed that the IVV system is useful to investigate ischemic brain. In the present report, IVV was applied to ischemic brain by 4-vessel occlusion in rat and changes in dopamine and serotonin metabolism were investigated by measuring peak 2 (3,4-dihydroxyphenylacetic acid, DOPAC) and peak 3 (5-hydroxyindoleacetic acid, 5-HIAA) in the striatum. The change of cerebral blood flow (CBF) were also assessed by a temperature-controlled thermoelectrical method in the striatum of the same model. The heights of peaks 2 and 3 were significantly increased to 600-900% and 200-300% respectively in the striatum during 30 minutes of 4-vessel occlusion. The increase of each peak was maximum at 10 minutes after occlusion. These changes may reflect that release of monoamine neurotransmitters is increased by the ischemia and outward transport of their metabolites are disturbed. On the other hand, after reperfusion by release of carotid occlusion, the heights of peaks 2 and 3 rapidly decreased below the control values, thereafter, peaks 2 and 3 gradually increased to over control values at 180-210 minutes after reperfusion. rCBF in the striatum decreased to almost 0 ml/100 g/min during 4-vessel occlusion ischemia and increased to over control values transiently for 30 minutes after reperfusion, followed by gradual decrease for about 240 minutes. Since monoamine neurotransmitters are known to have various effects on cerebral metabolism and CBF, their disorders may contribute to the change of CBF and the development of postischemic brain damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Structural abnormality and over-expression of the myc gene in feline leukemias.

Tumor cells of feline leukemia were examined for structural abnormality and expression of the myc gene. Four of 12 spontaneous leukemia cases showed structural abnormalities of the myc gene detected by Southern blotting analysis. Of these 4 cases, one (Case 1) showed a DNA rearrangement in the 5' portion of the c-myc locus associated with integration of feline leukemia virus (FeLV) genome. Another case had a newly inserted myc gene which was transduced by FeLV. In the 2 other cases, no relation of abnormalities of the myc gene to FeLV was detected. One case of experimental leukemia induced by inoculation of a cell line, FT-1, established from Case 1 showed a c-myc gene rearrangement similar to that observed in Case 1. Expression of myc RNA was examined in 3 leukemia T-cell lines, FT-1, FL74 and F422, by Northern blotting analysis. A high level of myc transcript was detected in all 3 cell lines. The size of myc RNAs in FT-1 and FL74 was the same as that of normal myc RNA, while in F422 which had myc-containing FeLV (myc-FelV), the full genome and spliced form of myc-FeLV viral RNA were detected.

Animals↗
PubMed1987

Genistein, a specific inhibitor of tyrosine-specific protein kinases.

Tyrosine-specific protein kinase activity of the epidermal growth factor (EGF) receptor, pp60v-src and pp110gag-fes was inhibited in vitro by an isoflavone genistein. The inhibition was competitive with respect to ATP and noncompetitive to a phosphate acceptor, histone H2B. By contrast, genistein scarcely inhibited the enzyme activities of serine- and threonine-specific protein kinases such as cAMP-dependent protein kinase, phosphorylase kinase, and the Ca2+/phospholipid-dependent enzyme protein kinase C. When the effect of genistein on the phosphorylation of the EGF receptor was examined in cultured A431 cells, EGF-stimulated serine, threonine, and tyrosine phosphorylation was decreased. Phosphoamino acid analysis of total cell proteins revealed that genistein inhibited the EGF-stimulated increase in phosphotyrosine level in A431 cells.

Cell Line↗
PubMed1987

Long-term continuous spinal anesthesia in severe tetanus with autonomic disturbance.

The mortality rate from tetanus is still high if the disease is accompanied by signs of autonomic nervous system dysfunction. We treated a 75-year-old woman with tetanus and autonomic dysfunction with continuous high spinal anesthesia for 23 days. She recovered. Spinal anesthesia may be a useful adjunct for the treatment of severe tetanus.

Aged↗
PubMed1987

Alterations of monoamine metabolites and of tryptophan in the basal cisternal CSF of patients after subarachnoid haemorrhage.

Homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and tryptophan (TRP) were measured in the CSF obtained from the basal cistern of 20 patients, who had undergone surgical obliteration of bleeding aneurysms within 3 days after subarachnoid haemorrhage (SAH). The concentrations of these substances, which were assayed by high performance liquid chromatography (HPLC), were the highest on days 3 or 4, and thereafter showed a gradual decrease with an increase in time. The cisternal CSF in patients who had severe preoperative clinical grades of SAH or vasospasm contained relatively higher concentrations of HVA, 5-HIAA and TRP than those contained in patients who did not. It is proposed that SAH stimulates the release of monoamines from the brain with the resultant extracellular accumulation of their metabolites and their diffusion into CSF during the acute stage. This stimulatory effect of SAH on the brain monoamine system may be consistent with those previously reported in cases of cerebral haemorrhage or infarction.

Female↗
PubMed1987

Regional differences in local cerebral blood flow (LCBF) and glucose utilization (LCGU) in the basal ganglia after occlusion of the middle cerebral artery in rats.

Acute effects of occlusion of the middle cerebral artery on local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were investigated quantitatively in separate groups of rats using (14C) iodoantipyrine (14C-IAP) or (14C) 2-deoxyglucose (14C-DG) respectively. LCBF was significantly decreased in the ipsilateral cerebral cortices (to less than 45 ml/100 g/min or 30% of the control side) and the lateral part of the striatum (to 22 ml/100 g/min or 10% of the control side) which were supplied by the middle cerebral artery. No significant changes in LCBF were found in any other of the subcortical regions. In contrast to the unanimous decrease of LCBF in the ipsilateral cortices and the lateral striatum, complexed changes in LCGU were found in not only the cortex and striatum but also in many other subcortical regions which were closely related to the distribution of the mesencephalic dopamine neurons, such as globus pallidus, substantia nigra, subthalamic nucleus, nucleus accumbens, olfactory tubercle and lateral habenular nucleus. Relevance of this putative neurotransmitter and GABA on the glucose metabolism in ischemic brain is discussed.

Animals↗
PubMed1987

Pathophysiology and prognosis of sudden deafness with special reference to the N1 latency.

Electrocochleography (ECochG) was performed in 84 patients with sudden deafness which were classified into 3 groups according to the ECochG findings, i.e. the unchanged N1 latency, the prolonged N1 latency and the absence of N1 response. The cause of hearing loss in the first group was thought to be strial, postsynaptic or mild cochlear damage and that in the second to be vascular, sensory or neural damage. The first group showed a better prognosis than those of the other two.

Adolescent↗
PubMed1987

Trigeminal sensory evoked potentials in patients with trigeminal neurinoma: report of two cases.

The trigeminal sensory evoked potentials (TEPs) in two patients with trigeminal neurinoma are reported. In contrast to the two cases previously reported by others, in which the preoperative TEPs were normal, the two cases reported herein showed significant changes on the affected side: the sensory thresholds were greater and the peak latencies of P19 and N28 were longer on the affected side than those on the normal side. Our results confirm that a TEP measurement is very useful in a preoperative examination of patients with trigeminal neurinoma, when the function of the trigeminal nerve should be evaluated objectively.

Cranial Nerve Neoplasms↗