Biomedical subjects

T Miyatake

Publications and source records attributed to T Miyatake.

At least 235 records · Page 13Linked to original sources

PubMed1989

[Chronic progressive external ophthalmoplegia (CPEO) with deleted mitochondrial DNA].

A 19-year-old man with chronic progressive external ophthalmoplegia with deleted mitochondrial DNA was reported. Neurological examination revealed bilateral external ophthalmoplegia, hearing loss of sensorineural type, short stature, mental retardation, muscle atrophy and weakness in the proximal muscles. Lactate and pyruvate levels were elevated in both serum and cerebrospinal fluid (CSF). Protein concentration was slightly increased in CSF. Electromyogram showed myopathic changes on all the muscles examined. Ragged-red fibers were found in biopsied rectus femoris muscle, stained with modified Gomori trichrome. Scattered cytochrome c oxidase deficient fibers were encountered. The computed tomography of the brain showed mild cerebral and cerebellar atrophy without any abnormal calcification or hypo-lucency. Southern blot analysis of the mitochondrial DNA (mtDNA) extracted from the patient's muscle revealed mixed population of mtDNA, consisting of the normal one and partially deleted one. The size of the deletion was about 4.5-kilobase. The region included the sequences coding for at least four subunits of Complex I, one subunit of Complex IV, two subunits of Complex V and five tRNAs. There may be a "hot area" on the mitochondrial genome that is more prone to be deleted than other regions of mtDNA. Southern blot analysis is usefull for the diagnosis of KSS or CPEO.

Adult↗

PubMed1989

[Vertebro-basilar artery occlusion in an 8-year-old boy].

An 8-year-old boy developed drowsy state, ataxia and right hemiparesis. Computed tomography and magnetic resonance imaging demonstrated ischemic lesions on bilateral cerebellar hemispheres, right thalamus and left pontine base. Angiography revealed occlusion of the left vertebral artery at the level of the second cervical spine and segmental narrowing of right vertebral artery from the level of the second to fifth cervical spine. Present case and previously reported cases suggest that vertebral artery could be stretched at the level of the second cervical spine and the intima may be injured to produce atherosclerosis.

Arterial Occlusive Diseases↗

PubMed1989

[The metabolism of glucose monitored by 13C-NMR in the gerbil brain in vivo-natural course and application to the ischemic model].

Glucose metabolism is altered in various pathologic conditions in the brain, i. e. ischemia, epilepsy and hypoglycemia. Therefore, analysis of glucose metabolism in pathologic conditions needs careful investigation of that in steady state. 13C-NMR method allows continuous sequential monitoring of changes in metabolism of glucose in vivo. The natural abundance of 13C is quite low (1.1%) and by administering 13C labelled in various skeleton in glucose, it is possible to monitor the metabolites in vivo. In this study, 13C glucose labelled in 1-position of carbon was employed to investigate the metabolic pathways in the control and transient ischemic gerbil brain with reperfusion. Male mongolian gerbils weighing 60-80 g were employed in this study. The gerbils were anesthetized by intraperitoneal administration of pentobarbital. The right skull was exposed and a surface coli was placed directly above the skull bone. After the operation, the animals were fastened to the NMR probe vertically. 500 mg/kg of [1-13C] glucose was injected via femoral catheter. 13C-NMR spectra were serially obtained before and after injection with GX-270 NMR spectrometer (JEOL, Tokyo, Japan, 6.34 T). In other series of experiments, 30 minutes of cerebral ischemia were induced after 15 minutes of glucose injection by the bilateral common carotid artery occlusion. In the normal gerbil brain, after administration of [1-13C] glucose (500 mg/kg), alpha and beta-anomers of [1-13C] glucose peak appeared abruptly and reached its peak level at 7.5-15 min acquisition period. The C2 peak representing glutamate and/or glutamine appeared later. The C3 and C4 peak started to appear even later at 30-40 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

[The observation of blood-brain barrier of organic mercury poisoned rat: a Gd-DTPA enhanced magnetic resonance study].

Permeability of the blood-brain barrier (BBB) of methylmercury chloride (MMC) intoxicated rat brain was studied in vivo by gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) enhanced magnetic resonance imaging (MRI), measuring the longitudinal relaxation time (T1) and the transverse relaxation time (T2). MMC intoxicated rat brain showed the prolonged T1 in the cerebral white matter and prolonged T2 in the cerebellar cortex. After Gd-DTPA administration, T1 of cerebral and cerebellar white matter shortened from 1.647 to 1.344 sec., and 1.290 to 1.223 sec. respectively. On the contrary, T2 showed no change after Gd-DTPA injection. It was concluded that, although the shortening of T1 after Gd-DTPA enhancement was rather little when compared with experimental brain ischemia, the shortening of the relaxation time of the MMC intoxicated rat brain was caused by the increased permeability of BBB.

Animals↗

PubMed1988

Accumulation of a globo-series glycolipid having Gal alpha 1-3Gal in PC12h pheochromocytoma cells.

In a previous paper, we reported the presence of globoside as a major neutral glycolipid in PC12 pheochromocytoma cells [Ariga, T., Macala, L. J., Saito, M., Margolis, R. K., Greene, L. A., Margolis, R. U., & Yu, R. K. (1988) Biochemistry 27, 52-58]. Recently, we found that subcloned PC12h cells accumulated another unusual neutral glycolipid. In order to characterize this glycolipid, PC12h cells were subcutaneously transplanted into rats. The induced tumor tissue accumulated two major neutral glycolipids, which were purified by Iatrobeads column and preparative thin-layer chromatographies. One of the glycolipids was found to be globoside, and the other had a globotriaosyl structure with an additional terminal Gal alpha 1-3 residue. Its structure was determined by fast atom bombardment mass spectrometry, two-dimensional proton nuclear magnetic resonance spectrometry (2D NMR), permethylation study, sequential degradation with exoglycosidase, and mild acid hydrolysis to be Gal(alpha 1-3)Gal(alpha 1-4)Gal(beta 1-4)Glc(beta 1-1')Cer.

Adrenal Gland Neoplasms↗

PubMed1988

Developmentally regulated alternative splicing of brain myelin-associated glycoprotein mRNA is lacking in the quaking mouse.

Evidence is presented that expression of the two myelin-associated glycoprotein mRNAs is developmentally regulated in mouse brain. In quaking mouse, the mRNA without a 45-nucleotide exon portion was scarcely expressed throughout development. We conclude that the mechanism of splicing out the 45-nucleotide exon portion is lacking in quaking mouse.

Amino Acid Sequence↗

PubMed1988

Biochemical analysis of decreased ornithine transport activity in the liver mitochondria from patients with hyperornithinemia, hyperammonemia and homocitrullinuria.

Hyperornithinemia, hyperammonemia and homocitrullinuria (HHH disorder) is an inherited metabolic disorder which shows peculiar amino acid changes in the serum and urine. The primary defect is considered to be the transport of ornithine across the mitochondrial membrane, but there is no direct evidence for this so far. We have analyzed ornithine transport activities in the liver mitochondria from three patients with HHH disorder. In coupled liver mitochondria we demonstrated low activities of citrulline synthesis and low rates of ornithine uptake. However, there were no abnormalities in carbamoyl-phosphate synthetase activity, ornithine carbamoyltransferase activity, N-acetylglutamate levels or O2 uptake with succinate. We also performed a kinetic study of citrulline synthesis as a function of ornithine concentration. We found increased Km values for ornithine and varied Vmax values of citrulline synthesis, which suggested the presence of a mutant transport protein. From these results we conclude that the defect of hyperornithinemia, hyperammonemia and homocitrullinuria lies in the transport of ornithine across the mitochondrial membrane.

Amino Acid Metabolism, Inborn Errors↗

PubMed1988

Suppressive effect of camostat mesilate (FOY 305) on acute experimental allergic encephalomyelitis (EAE).

Camostat mesilate (FOY305), a synthetic serine protease inhibitor and has been developed as a drug for pancreatitis, is effective in suppressing acute experimental allergic encephalomyelitis in Lewis rats. Loss of weight, clinical score and yield of myelin protein from brain stem were improved by daily injection of FOY305 compared with saline from day 6 after inoculation with homogenate of guinea pig spinal cord. A significant decrease of yield of myelin has been shown here for the first time in acute EAE in Lewis rat. This is in accord with myelin breakdown demonstrated morphologically. Our study also demonstrates a significant improvement of yield of myelin protein by FOY305. Our results suggest the possibility of a clinical application of this protease inhibitor for human demyelinating diseases such as multiple sclerosis.

Animals↗

PubMed1988

Alterations of oligodendrocytes and demyelination in the spinal cord of patients with mitochondrial encephalomyopathy.

The spinal cords of 2 autopsied patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) were examined. Histologically, the spinal cords showed a spongy state due to the presence of distended myelinated fibers with enlarged periaxonal spaces. Ultrastructurally, the affected fibers showed extensive microvacuolation of the inner myelin sheath with occasional vesicular changes. The presence of macrophages near the degenerated myelin was a frequent finding. The stripping of myelin lamellae by macrophage was observed, with frequent appearance of denuded axons. Furthermore, prominent morphological changes were observed in oligodendrocytes. These findings indicate that demyelination, probably secondary to the degeneration of oligodendrocytes, occurs in the spinal cord of MELAS.

Adolescent↗

PubMed1988

Human placental sialidase: further purification and characterization.

An acid sialidase [EC 3.2.1.18] has been purified from human placenta by means of successive procedures including extraction, Con A-Sepharose adsorption, ammonium sulfate precipitation, activation, p-aminophenyl thio-beta-D-galactoside-CH-Sepharose (PATG-Sepharose) affinity chromatography and high-performance liquid chromatography on a Shim pack Diol 300 column. The purified enzyme liberated sialic acid residues from sialooligosaccharides, sialoglycoproteins, and gangliosides. In particular, gangliosides GM3, GD1a, and GD1b were hydrolyzed much faster than alpha (2-3) and alpha (2-6)sialyllactoses, and sialoglycoproteins by the enzyme. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified enzyme gave five protein bands with molecular weight of 78,000 (78K), 64,000 (64K), 46,000 (46K), 30,000 (30K), and 20,000 (20K). Rabbit antisera were raised against 78K and 46K proteins, and the two antibodies were specifically reactive with the respective component on immunoblot analysis. Both anti-78K protein and anti-46K protein antisera could precipitate sialidase activity. It is likely that the 78K protein and 46K protein are sub-components which are essential for sialidase activity.

Female↗

PubMed1988

Myelin-associated calpain II.

Anti-chicken muscle calpain (calcium-activated neutral protease) antibody (ACAb) was found to be absorbed by purified human brain myelin when titrated by enzyme-linked immunosorbent assay, suggesting the close association of the protease with myelin. To confirm this, calcium-dependent protease was extracted from myelin membrane and purified on a phenyl Sepharose CL 4B column. It was activated by calcium ion in the millimolar range, and therefore was determined to be calpain II. This enzyme fraction was electrophoresed and immunostained with ACAb, resulting in staining as a single band with apparent molecular weight of 80K. This protease degraded exogenous myelin-associated glycoprotein. From the present results, it is suggested that calpain is bound to myelin membrane and involved in the turnover of myelin proteins.

Animals↗

PubMed1988

IgM binding to sialosyllactosaminylparagloboside in a patient with polyradiculoneuropathy due to Mycoplasma pneumoniae infection.

IgM in serum without paraprotein in a patient with polyradiculoneuropathy due to a Mycoplasma pneumoniae infection reacted specifically with a ganglioside, sialosyllactosaminylparagroboside (SLPG), in a human peripheral nerve on a thin-layer chromatogram plate by an immunostaining technique. This finding suggests the possibility that anti-SLPG antibody in the patient's serum may play a role in the pathogenesis of neuropathy.

Female↗

PubMed1988

Serum antibodies to brain proteins in a patient with parkinsonism associated with IgM paraproteinemia.

We report a 58 year-old man with various neurological symptoms as parkinsonism, autonomic dysfunction, mental deterioration and lower motor neuron involvement associated with IgM gammopathy whose serum showed antibody activities to human brain proteins. His serum reacted with 156kDa protein from substantia nigra and 130kDa of cerebral cortical grey matter, cerebellar cortex, putamen, thalamus or pallidum by immunoblotting method. The serum of this patient reacted with proteins widely distributed in the central nervous system, and this antibody in his serum might be the cause of his various neurological symptoms.

Autoantibodies↗

PubMed1988