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Biomedical subjects

Y Nagane

Publications and source records attributed to Y Nagane.

30 records · Page 2Linked to original sources
PubMed1998

Alterations with aging and ischemia in nicotinic acetylcholine receptor subunits alpha4 and beta2 messenger RNA expression in postmortem human putamen. Implications for susceptibility to parkinsonism.

Nicotine activates the dopaminergic system and acts to alleviate hypokinetic disorders (parkinsonism). The frequency of parkinsonism increases with age and is sometimes associated with multiple small infarcts (status lacunaris) in the putamen. To investigate changes with aging in control cases free from neurological disease and changes in cases with multiple small infarcts (status lacunaris) in the putamen, the present study determined nicotinic acetylcholine receptor (nAChR) subunit alpha4 and beta2 messenger RNA (mRNA) expression in the postmortem human putamen using the reverse transcription-polymerase chain reaction (RT-PCR). In controls, alpha4 subunit mRNA expression was unaltered, but beta2 subunit mRNA expression decreased significantly with age. In cases with status lacunaris, both beta2 and alpha4 subunit mRNA expressions were significantly lower than in the control cases. The reduction in beta2 mRNA expression alone, or in both alpha4 and beta2 mRNA expressions, suggests a reduction in functional nAChRs in the putamen, which may in part explain the susceptibility to hypokinetic disorders of the elderly and subjects with ischemic damage in the striatum.

Adult↗
PubMed1998

Age-related changes in nicotinic acetylcholine receptor subunits alpha4 and beta2 messenger RNA expression in postmortem human frontal cortex and hippocampus.

Age-related changes in nicotinic acetylcholine receptor (nAChR) subunit alpha4 and beta2 messenger RNA (mRNA) expression in the postmortem human frontal cortex and hippocampus was investigated using the reverse transcription-polymerase chain reaction (RT-PCR). In the frontal cortex, both alpha4 and beta2 subunit mRNA expression decreased with age. In the hippocampus, alpha4 subunit mRNA expression was unaltered, while beta2 subunit mRNA expression significantly decreased with age. These findings suggest that nAChR transcription decreases during aging with differing vulnerability between subunits and brain regions, which could in part contribute to the reduction in cognitive functions seen in the elderly.

Adult↗
PubMed1998

Age-related changes in D1 and D2 receptor mRNA expression in postmortem human putamen with and without multiple small infarcts.

Expression of messenger RNAs (mRNAs) encoding the D1 and D2 dopamine receptors as a function of age was determined in the human putamen using the reverse transcription-polymerase chain reaction (RT-PCR). In cases without multiple small infarcts (status lacunaris) in the putamen, D1 mRNA expression was unaltered, while D2 mRNA expression significantly decreased with age. Both D1 and D2 mRNA expression was lower in cases with status lacunaris. The reduction in D1 receptors primarily located on striatonigral neurons or D2 receptors primarily located on striatopallidal neurons may inhibit thalamocortical neurons. The decreased transcription of D1 and D2 receptor genes may in part account for increased susceptibility to hypokinetic disorders in the elderly.

Actins↗
PubMed1998

Familial amyloid polyneuropathy related to transthyretin mutation Val30 to Leu in a Japanese family.

A rare variant transthyretin that has a leucine-for-valine substitution at position 30 was reported in a sporadic case of type 1 familial amyloid polyneuropathy (FAP). We found the same substitution in members of a Japanese family with FAP. Three individuals in this family had a guanine-to-cytosine mutation at the first base of codon 30 in exon 2. This family shows a direct link between a valine-to-leucine substitution at position 30 and type 1 FAP.

Amino Acid Substitution↗
PubMed1998

[A case of chronic, motor, axonal polyneuropathy successfully treated by immunoadsorption].

We reported a 61-year-old male with chronic, motor, axonal polyneuropathy. Neurological examination revealed severe muscle weakness in the proximal parts of the four limbs. Sensory examination was normal. The cerebrospinal fluid protein was elevated to 74 mg/dl, and the cell count was normal. The serum antibodies to GM1, GD1a, GD1b, and GQ1b were all negative. Electrophysiological studies showed reduced compound muscle action potentials (CMAPs) suggesting axonal neuropathy, and the nerve conduction velocity was only mildly reduced. After treatment with plasmapheresis (PP) by the immunoadsorption method, his symptoms significantly improved in three weeks, and the cerebrospinal fluid protein, and CMAPs also improved. Only a few studies have been reported regarding patients with chronic, motor dominant, axonal polyneuropathy that responded to immunosuppressive therapies or PP. It remains to be determined whether chronic, dominantly motor, axonal polyneuropathy as seen in the present case is a subtype of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) or a primary axonal immune-mediated neuropathy that is different from CIDP. At present we are not able to answ what kind of clinical or laboratory markers other than an elevated cerebrospinal fluid protein level may help to predict a positive response to immunosuppressive therapy or PP.

Axons↗
PubMed1997

Reduction in the ratio of beta-preprotachykinin to preproenkephalin messenger RNA expression in postmortem human putamen during aging and in patients with status lacunaris. Implications for the susceptibility to parkinsonism.

Gamma-aminobutyric acid (GABA)/substance P (SP) neurons and GABA/enkephalin (Enk) neurons in the striatum exert opposing influence on the regulation of movement. The loss of GABA/SP neurons results in hypokinetic disorders (parkinsonism), whereas the loss of GABA/Enk neurons results in hyperkinetic disorders (e.g. chorea). The present study determined age-related changes in the beta-preprotachykinin (the precursor of SP) and preproenkaphalin (the precursor of Enk) messenger RNA (mRNA) ratio in the postmortem human putamen using the reverse transcription-polymerase chain reaction (RT-PCR). The ratio of beta-preprotachykinin to preproenkephalin mRNA expression decreased with age. The reduction in the beta-preprotachykinin/preproenkephalin mRNA ratio was more marked in cases with multiple small infarcts (status lacunaris) in the putamen. These findings may in part explain the susceptibility of the elderly, particularly of those with ischemic changes in the striatum to hypokinetic disorders.

Adult↗
PubMed1997

[Distribution of CD44 highly-positive cells in relation to hyaluronic acid and basement membrane in myasthenia gravis thymus].

We studied the distribution of CD44-highly positive cells in relation to its ligand hyaluronic acid (HA) and basement membrane in hyperplastic thymuses from myasthenia gravis (MG) patients. CD44-highly positive cells were markedly increased in the hyperplastic MG thymuses as compared with control thymuses. They were present in subcapsular and cortical areas, sometimes extending to the medullary areas. The distribution of CD44-highly positive cells in the MG thymus was close to the sites with strong HA staining at blood vessel walls and extraparenchymal connective tissue. In the hyperplastic MG thymuses, the basement membrane surrounding extralobular blood vessels and the lobules was perforated or interrupted. These changes may allow the CD44-highly positive cells to penetrate into the hyperplastic MG thymuses.

Adolescent↗
PubMed1997

[Effects of CTG repeat expansion on quantitative muscle histopathology in myotonic dystrophy].

The CTG trinucleotide repeat (CTG repeat) length in leukocytes and muscles shows significant correlations with muscle weakness, an increase in type 1 fiber proportion, and reductions in type 2A and 2B fiber proportions in patients with myotonic dystrophy (DM). The correlations are generally greater for CTG repeat length in muscles than in leukocytes. However, relatively small absolute values of correlation coefficients (r2 = 0.13-0.43) suggest that the CTG repeat length is not a role variable that may explain clinical and histopathological changes in DM patients.

Adult↗
PubMed1996

[TCR alpha beta + CD4- CD8- T cells among the peripheral blood mononuclear cells of myasthenia gravis patients].

We investigated the occurrence of TCR alpha beta + CD4- CD8- mononuclear cells (DN alpha beta T cells) and TCR gamma delta + CD3+ mononuclear cells (gamma delta T cells) among the peripheral blood mononuclear cells of 22 myasthenia gravis patients (MG) and 22 controls in order to examine whether extrathymic T cell subpopulations might be responsible for the pathogenesis of MG. The differences between the mean percentages of both DN alpha beta T cells and gamma delta T cells in the MG patients (DN alpha beta T cells: 0.53 +/- 0.51%, gamma delta T cells: 3.45 +/- 2.79%) and the controls (DN alpha beta T cells: 0.32 +/- 0.16%, gamma delta T cells: 3.81 +/- 2.36%) were not significantly different. However, higher DN alpha beta T cells ratios (1.48 approximately 1.84%) were noted in three MG patients. Thymectomy and subsequent thorough dissection of the anterior mediastinum 3 years after thymectomy had no effect on the symptoms of one patient, a 25-year-old woman without thymoma. The other two patients, a 45-year-old man and a 41-year-old woman without thymoma, had recurrences despite long-term remissions (14 years and 30 years, respectively) after thymectomy. Examination of DN alpha beta T cells, which are probably generated extrathymically without negative selection, may play an important role in understanding the pathogenesis in these three cases of MG.

Adult↗
PubMed1995

Heat-shock cognate 70 messenger RNA expression in postmortem human hippocampus: regional differences and age-related changes.

In situ hybridization of postmortem human brain tissue showed that constitutive heat-shock cognate 70 (hsc 70) mRNA was expressed in more than 50% of the pyramidal neurons in the hippocampal subfields. The ratio (%) of the hsc 70 mRNA-expressing neurons to the total neurons was significantly greater in CA3 and the hilus than in CA1 and CA2. The lower ratio in CA1 may be related to its vulnerability to various stresses. The ratio of hsc 70 mRNA-expressing neurons in CA1 was significantly greater in the older subjects than in the younger ones. This may reflect the up-regulated hsc 70 mRNA induction in response to a reduction in free hsc 70 because the binding of hsc 70 to aberrant proteins may be increased in aged persons.

Adult↗
PubMed1984

Nephrogenic adenoma of the ureter.

We report a case of nephrogenic adenoma in the left ureter. The patient presented with lumbago on the left side. A small calculus was incarcerated in the left ureter 4 cm. from the ureteropelvic junction and an adenoma, which resembled histologically the renal tubules, was observed in the ureter. A search of the world medical literature revealed 58 cases of nephrogenic adenoma, although only 1 case in the ureter has been reported previously.

Adenoma↗