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Biomedical subjects

T Miyatake

Publications and source records attributed to T Miyatake.

At least 181 records · Page 10Linked to original sources

Distinct clustering of point mutations in mitochondrial DNA among patients with mitochondrial encephalomyopathies and with Parkinson's disease.

The total sequence data for mitochondrial DNA (mtDNA) revealed distinct clustering of point mutations (pms) in mtDNA among one patient with myoclonus epilepsy with ragged-red fibers (MERRF), two patients with Parkinson's disease (PD), two patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and one patient with fatal infantile cardiomyopathy (FICM). Among 33 to 62 pms found in each patients, sequentially diverged five clusters of pms were detected and designated as C-1 to C-5. C-1, consisted of fourteen pms, existed in the MERRF patient, C-1 and C-2 (nine pms) in one PD patient, C-1 to C-3 (seven pms) in another PD patient, C-1 to C-4 (one pm) in one MELAS patient and C-1 to C-5 (three pms) in another MELAS patient and the FICM patient. From these clustering of pms, a phylogenetic tree of mitochondrial encephalomyopathies (ME) was constructed. This tree clearly indicated that the ME and PD patients are members of the same gene family, and the MELAS and FICM patients are each others' closest relative. Each patient's unique pms (14 to 28 pms) were detected and, from their characteristic features, the types of the mutations specific for the disease were classified as mit- + syn- for MERRF, mit- + p- for PD, and syn- + mit- for MELAS. An inverse relation was found between the total number of pms and life span of the MELAS and FICM patients.

Adolescent↗

Study on the erythrocytes from myotonic dystrophy with multi-nuclear NMR.

We have studied the water permeability through membranes, the function of the Na pump, and glucose metabolism of erythrocytes of patients with myotonic muscular dystrophy (MyD) using 1H--, 23Na, and 13C-NMR techniques. A significant decrease in water permeability was recognized in the MyD erythrocyte membrane, and impaired Na pumping was suspected to be correlated with the former biochemical abnormalities in band III protein of MyD erythrocyte membrane. Significant acceleration of glycolysis in the erythrocyte for the first 160 minutes was also recognized in MyD; however, the production of lactate showed no difference between MyD and controls. The increased glucose uptake in MyD may be compensatory to the diminished pumping mechanism, but further information, such as inorganic phosphate permeability and the activity of the rate-limiting enzyme of erythrocyte glycolysis, is needed.

Adolescent↗

Galactosialidosis: neuropathological findings in a case of the late-infantile type.

The neuropathological findings in a 13-year-old Japanese male showing decrease of sialidase and beta-galactosidase activities are reported. The patient was the product of normal pregnancy to consanguineous parents. He started to sit at 8 months, stand at 20 months and walk at age of 2; mental retardation, visual disturbance, cerebellar ataxia, myoclonus and epilepsy developed by the age of 10, and he died at 13. Neuropathological investigation revealed neuronal loss and storage. Severe loss of neurons was observed in the thalamus, globus pallidus, lateral geniculate body, gracile nucleus, Purkinje and retinal ganglion cells. Marked ballooning was seen in the Betz cells and neurons in the basal forebrain, the motor neurons in the cranial nerve nuclei and spinal cord, and in the trigeminal and spinal ganglia. The storage material varied in staining from region to region and from neuron to neuron. Electron microscopic investigation revealed a variety of intracytoplasmic and intranuclear inclusions: membranous cytoplasmic bodies, parallel, wavy-lamellar or tortuous tubular structures, lipofuscin-like irregular-shaped pleomorphic bodies, and cytoplasmic vacuoles with fine granules and lamellar materials. The severity of the neuronal loss did not seem to correlate with the amount of the storage materials, but with the presence of tortuous tubular inclusion.

Brain↗

Construction of spinal cord cDNA library and application for subtractive cloning of spinal cord-specific cDNAs.

Neurodegenerative diseases are characterized by neuronal degeneration of specific neurons, e.g., degeneration of motoneurons in amyotrophic lateral sclerosis. As an approach to understand molecular mechanisms of neuronal degeneration of human spinal cord motoneurons in various motor neuron diseases, we have constructed a human spinal cord cDNA library and developed a strategy for isolating spinal cord-specific genes by subtractive cloning. We constructed human spinal cord and brain cDNA libraries from postmortem human spinal cord and brain. To isolate human spinal cord-specific cDNAs, a spinal cord-enriched [32P]cDNA probe was generated by the phenol emulsion reassociation technique. Forty-eight cDNA clones out of 10,000 colonies gave strong signals with the subtracted probe, and individual spinal cord cDNA clones were isolated. Northern blotting analysis confirmed that two spinal cord cDNA clones are, in fact, more abundant in spinal cord compared to brain.

Blotting, Northern↗

Physiological significance of fatty acid elongation system in adrenoleukodystrophy.

We studied the metabolism of radioactive fatty acids in cultured skin fibroblasts from patients with adrenoleukodystrophy (ALD) and Zellweger syndrome (ZS) to clarify the physiological significance of the fatty acid elongation system in the accumulation of very long chain fatty acids (VLFA) in ALD. A substantial amount of radioactive C26:0 was synthesized from [18-14C]stearic acid by ALD and ZS fibroblasts, whereas radioactive C26:0 was not detected in control fibroblasts. Kinetic studies demonstrated that the production of radioactive C24:0 and C26:0 in ALD fibroblasts is higher than that of ZS fibroblasts, which suggests that the fatty acid elongation activity plays an important role for the accumulation of VLFA in ALD, in addition to the decreased VLFA oxidation activities. The addition of monounsaturated fatty acids including oleic acid and erucic acid specifically lowered the formation rate of VLFA without any significant effect on degradation activities of VLFA both in ALD and control fibroblasts. The results suggest that the mechanism of decrease of VLFA by administration of monounsaturated fatty acids is based on the inhibition of fatty acid elongation activity.

Adrenoleukodystrophy↗

A new method to measure the distribution of motor conduction velocity in man.

A new method of measuring the distribution of conduction velocities in human motor fibers is described. In this method, a modification of Kimura's collision technique is combined with Hopf's technique. This enabled us to determine the collision end-point in Hopf's technique, from which the minimum velocity is derived. The size of the distorted compound muscle action potential (CMAP) measured with Hopf's technique is corrected using the CMAP size with the modified Kimura technique. This resolves the problem of CMAP distortion due to transient change in muscle conduction in Hopf's technique. In addition, a new equation to correct for the refractory period was developed. This can be applied even if there is stimulus spread. Using our method, one can clearly determine the maximum and minimum velocities. The former corresponds to the motor conduction velocity as measured by the conventional method.

Action Potentials↗

Isolation and characterization of major urinary oligosaccharides excreted by a patient with type 3 GM1 gangliosidosis.

Two major oligosaccharides were isolated from the urine of a patient with type 3 GM1 gangliosidosis. From structural studies including compositional sugar analysis, fast-atom bombardment mass spectrometry, direct-inlet chemical ionization mass spectrometry, methylation analysis, chromium trioxide oxidation, and proton magnetic resonance spectroscopy, their structures were deduced to be as follows: [formula: see text] Both oligosaccharides have beta-linked galactose at the non-reducing ends. Oligosaccharide 1 is one of the most common urinary oligosaccharides found in type 1 and type 2 GM1 gangliosidosis. Oligosaccharide 2, lacto-N-difucohexaose II, has not been described in the urine of GM1 gangliosidosis patients. Excretion of oligosaccharide 1 in the type 3 patient was much less than that of a type 2 patient. Thin-layer chromatographic analysis revealed that the excretion of oligosaccharides with higher molecular weight than that of oligosaccharide 1 (octasaccharide) in the type 3 patient was much less than that of a type 2 patient, raising the possibility that the mutant beta-galactosidase of type 3 GM1 gangliosidosis can still act to some extent on higher molecular weight oligosaccharides containing beta-linked galactose at the non-reducing end.

Carbohydrate Conformation↗

Adult-form galactosialidosis: ocular findings in three cases.

We reported ocular findings of 3 patients with adult-form galactosialidosis. Diffuse fine opacities in the deep layer of the corneal stroma, an obscure cherry-red spot of the macula and optic nerve atrophy were noted in all cases. Punctate lenticular opacities were observed in 2 cases. Slowly progressive visual disturbance was seen in all cases, and it might be due to secondary optic nerve atrophy caused by retinal ganglion cell death.

Adult↗

Absence of highly homologous sequence to HTLV-I in Japanese multiple sclerosis.

We tried to detect HTLV-I-related sequences in Japanese patients with multiple sclerosis with a highly sensitive method that employs the polymerase chain reaction (PCR) of genomic DNA followed by Southern blot hybridization analysis. To amplify HTLV-I sequences, we used primers for LTR, pol, gag, and env coding regions. Fourteen patients with definite MS, 14 disease controls, 12 normal controls, and 3 patients with HTLV-I-associated myelopathy (HAM) were investigated. Results of particle aggregation assay for HTLV-I antibodies were negative in serum from all subjects except for the 3 HAM patients. Neither the 14 MS patients nor the 26 controls showed the presence of any highly homologous sequences to HTLV-I. We did observe faint signals for gag, pol, and env coding regions only at low stringent hybridization in some MS patients as well as some normal controls. The nucleotide sequence analysis of the faint bands was more homologous to major histocompatibility complex molecules than the HTLV-I genome.

Adult↗

HLA-B35 and acute axonal polyneuropathy following Campylobacter infection.

We performed HLA typing for class I antigens on five Japanese patients with acute polyneuropathy following Campylobacter infection, all of whom showed axonopathy causing pure motor dysfunction associated with IgG anti-GM1 antibodies. We demonstrated a statistically significant association between the disease and the HLA-B35 antigen.

Acute Disease↗

Simple detection of tRNA(Lys) mutation in myoclonus epilepsy associated with ragged-red fibers (MERRF) by polymerase chain reaction with a mismatched primer.

We developed a simple method for the detection of a tRNA(Lys) mutation in myoclonus epilepsy associated with ragged-red fibers (MERRF) by polymerase chain reaction with use of a mismatched primer. Although the tRNA(Lys) mutation does not alter recognition sequences for commercially available restriction enzymes, we have successfully changed two nucleotides flanking the A to G mutation at nucleotide position 8344 in a tRNA(Lys) gene of a mitochondrial genome. As a result, the mutation can be detected as a Nae I restriction fragment length polymorphism. With this method, all eight MERRF patients and an asymptomatic mother of a MERRF patient, from six independent families, had the same tRNA(Lys) mutation. Our method is simple and should also be useful for the quantitation of heteroplasmies.

Base Sequence↗

Linkage analysis of juvenile parkinsonism to tyrosine hydroxylase gene locus on chromosome 11.

We performed linkage analyses of juvenile parkinsonism with autosomal recessive inheritance (AR-JP) to chromosome 11p15.5 locus including tyrosine hydroxylase (TH), Harvey-ras-1 (HRAS), and insulin (INS) genes by analyzing genomic DNA from 28 members of seven Japanese AR-JP families containing 10 affected individuals. We used the methods of pairwise linkage analysis (LIPED) and multipoint linkage analysis (LINKAGE) for genetic linkage to the chromosome 11p15.5 markers and detected recombination events between AR-JP locus and TH gene. Multipoint linkage analysis excluded the linkage in the interval between TH and HRAS, as well as 11 cMo distal to TH and 8.5 cMo distal to HRAS, a total of approximately 23 cMo on chromosome 11p.

Adolescent↗

Creutzfeldt-Jakob disease in a patient with a cadaveric dural graft.

We report a 26-year-old woman with Creutzfeldt-Jakob disease (CJD) who had received cadaveric dural material 33 months before the onset of neurologic symptoms. This is the fourth case in which a dural graft was the putative source of the CJD agent. All four cases had the grafting before changes in the sterilization procedure adopted in 1987 to inactivate the CJD agent.

Adult↗

Identification of a mutation in the arylsulfatase A gene of a patient with adult-type metachromatic leukodystrophy.

To analyze the genetic abnormality in a Japanese patient with adult-type metachromatic leukodystrophy (MLD), we first elucidated the genomic organization of the human arylsulfatase A (ASA) gene and then compared the nucleotide sequences of exons and splice junctions of the mutant ASA gene to those of a normal control. We have identified a new mutation, a G-to-A transition in exon 2, which results in amino acid substitution of Asp for 99Gly. In a transient expression study, COS cells transfected with the mutant cDNA carrying 99Gly----Asp did not show an increase of ASA activity, which confirms that the mutation is a cause of adult-type MLD.

Adult↗

[The correlation of consciousness level and the concentration of CSF ammonia in a patient with adult-type citrullinemia].

A 29-year-old man who had a taste for peanuts frequently showed abnormal behaviors. Physical examination revealed consciousness disturbance associated with flapping tremor, hypotonus in the extremities, and hypoactive deep tendon reflexes. Laboratory examination showed hyperammonemia with mild liver injury. A level of serum citrulline was 14 times higher than the upper limit of normal. A diagnosis of type 2 citrullinemia (Seheki et al) was established by the decreased argininosuccinate synthetase (ASS) in liver with low amount of ASS protein and normal kinetic properties. Diurnal fluctuation of consciousness level in this patient was not correlated with the concentration of ammonia in serum, but with that in cerebrospinal fluid. Main metabolic pathway of ammonia in brain is considered to be localized in astrocytes which have receptors for glucocorticoids. Glucocorticoids induce additional glutamine synthetase activity. Circadian rhythm of cortisol level might play a role in diurnal fluctuation of consciousness level in patients with citrullinemia.

Adult↗