Search PubMed⌕ Search

Biomedical subjects

Y Ohyagi

Publications and source records attributed to Y Ohyagi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Selective increase in cellular A beta 42 is related to apoptosis but not necrosis.

Amyloid beta protein ending at 42 (A beta 42) plays an important role in the pathology of Alzheimer's disease (AD). Here we show an increase in cellular A beta 42 in damaged neurons, with both ELISA and immunocytochemistry. The cellular A beta 42 increase was caused by 3-day treatments with H2O2, etoposide or melphalan, all of which induce genotoxic apoptosis, but not by treatment with sodium azide, which causes necrosis. Secreted A beta was similarly decreased with all these treatments. The cellular A beta 42 increase appeared even with minimal damage (ELISA) and A beta 42-positive cells were TUNEL negative (double staining), indicating that any early apoptosis mechanism may induce the cellular A beta 42 increase. Thus, neuronal apoptosis and cellular A beta 42 increase may be linked in a way that contributes importantly to AD pathology.

Amyloid beta-Peptides↗
PubMed2000

Lovastatin does not correct the accumulation of very long-chain fatty acids in tissues of adrenoleukodystrophy protein-deficient mice.

Lovastatin, an inhibitor of 3-hydroxy-3-methylglutarylcoenzyme A reductase, normalizes the very long-chain fatty acids (VLCFA) concentrations in fibroblasts and plasma from patients with X-linked adrenoleukodystrophy (X-ALD). The effects of lovastatin on the accumulation of VLCFA in tissues of adrenoleukodystrophy protein (ALDP)-deficient mice were assessed. ALDP-deficient mice were fed chow with 0.01-0.1% lovastatin for 4-8 weeks. The VLCFA concentrations in the plasma, brain, spinal cord, liver and kidneys were measured. Treatment with 0.1% lovastatin significantly reduced body weight and total cholesterol in the plasma of ALDP-deficient mice. Treatment with lovastatin, however, did not correct the accumulation of VLCFA in the plasma or tissues, including the brain and spinal cord. Lovastatin does not affect the accumulation of VLCFA in ALDP-deficient tissues in mice.

ATP Binding Cassette Transporter, Subfamily D, Mem↗
PubMed2000

Acute myelitis after asthma attacks with onset after puberty.

A poliomyelitis-like illness after asthma attacks has been found and is called asthmatic amyotrophy (Hopkins' syndrome). All of the previously reported cases were under 13 years of age. Three patients are described who developed acute myelitis after asthma attacks at 15, 22, and 73 years of age. All of them showed acute flaccid monoparesis, and needle EMG disclosed denervation potentials in the relevant muscles. In addition, in the two adult patients the sensory or pyramidal tracts were involved, and evoked potential studies confirmed an involvement of the pyramidal tracts in one of them. This 22 year old patient showed a second episode of monoparesis in the other limb after another asthma attack. All three patients had no significant changes in their antiviral antibody titres, whereas every patient had hyperIgEaemia and allergen specific IgE. These findings suggest that asthmatic amyotrophy can develop after puberty and that patients who develop this disease in adulthood seem to show both a widespread involvement of the spinal cord and a more varied course.

Acute Disease↗
PubMed2000

Hyperprolactinemia in optico-spinal multiple sclerosis.

OBJECTIVE: To clarify the clinical features of MS patients with hyperprolactinemia. SUBJECTS AND METHODS: The serum prolactin level was measured in 67 Japanese patients (19 men and 48 women) with multiple sclerosis (MS) and in 16 patients (4 men and 12 women) with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) using a two-site immunoradiometric assay. RESULTS: In the MS patients, 32 were classified as having Asian type MS showing a selective involvement of the optic nerves and spinal cord, while the other 35 were classified as having Western type MS which displayed disseminated central nervous system involvement. In women, the serum prolactin level was found to be significantly higher only in Asian type MS (mean=23.1 ng/ml, n=25) than in HAM/TSP (mean=6.9 ng/ml, n=12) (p=0.0297), while it did not differ significantly in men among the three groups. Hyperprolactinemia was significantly associated with acute relapse involving the optic nerves. All MS patients with hyperprolactinemia (7 women with Asian type MS and 2 women with Western type MS) showed recurrent opticomyelitis either throughout or in the early course of the disease, and also had a higher age of onset, a higher Expanded Disability Status Scale score, a greater visual impairment, and higher cell counts and protein contents in the cerebrospinal fluid than did the normoprolactinemic patients. CONCLUSION: Hyperprolactinemia may be one of the characteristic features of Asian patients with MS who preferentially show the optic nerve involvement.

Adult↗
PubMed2000

[A case of amoxapine-induced tardive dystonia successfully treated with a low dose anti-cholinergic agent].

We report a 63-year-old man who presented with amoxapine-induced tardive dystonia. At 49 years of age, he developed depression and was administrated 50 mg amoxapine, 4 mg cloxazoram and 3 mg biperiden per day. The daily dose of amoxapine was gradually increased up to 150 mg at 58 years of age. At 61 years of age and after having been taking amoxapine for twelve years, he noticed a rotating left arm and muscle pain in his left shoulder and arm while walking. At 62 years of age, he stopped taking these three drugs. However, the dystonic movements and pain both continued to get worse. Neurological findings revealed no abnormality except for a dystonic posture and movements in the neck and bilateral arms while sitting, standing and walking. Positron emission tomography with C-11 raclopride revealed a mild decrease in the dopamine D 2 receptor numbers in the bilateral striatum. However, two dopamine agonists, pergolide and bromocriptine, worsened his dystonia. In contrast, the daily administration of 2 mg of trihexyphenidyl, an anti-cholinergic agent, markedly ameliorated the dystonia symptoms. As a result, the long-term co-administration of biperiden, an anti-cholinergic agent, may mask the toxicity of amoxapine, which may induce tardive dystonia.

Amoxapine↗
PubMed2000

[A patient with limb-girdle type myasthenia gravis and atopic dermatitis, both of which improved after thymectomy].

We herein report a patient with myasthenia gravis (MG) and atopic dermatitis (AD). Heretofore, there have been no reports of patients with MG and AD. Nine years ago, a 25-year-old man noted muscle weakness of upper and lower extremities on physical labor, and the muscle weakness was gradually exacerbated. Two years ago, he noted acute skin eczema with itching on his hands and feet. Neurological examination revealed mild left ptosis, facial muscle weakness and proximal muscle weakness of upper and lower extremities, but no diplopia, ophthalmoplegia or dysphagia. Although anti-nicotinic acetylcholine receptor antibody was negative, edrophonium test was positive and 54% waning in the thenar muscles was observed on Harvey-Masland test. Thus, he was diagnosed as limb-girdle type MG. IgE level in his serum elevated (1,818 U/ml). After thymectomy, the muscle weakness markedly improved as well as waning in the thenar muscles (11%). Simultaneously, AD markedly improved and serum IgE level was decreased (1,245 U/ml). Thus, MG and AD in this case may be derived from some common immunological aberrancy in the thymus.

Adult↗
PubMed2000

[A case of mortor neuron syndrome with onset 9 months after electrical injury].

A 72-year-old man noticed progressive weakness of both upper limbs, more severe on the left side, 9 months after an electric shock of a 20,000 V alternating current. He had diffuse scars of superficial burns with skin graft in four limbs, more on the right side. A neurological examination revealed diffuse muscle atrophy, weakness and fasciculation in both upper limbs, predominantly on the left side, hyper-reflexia in four limbs with mildly exaggerated jaw jerk, left Babinski sign, and mild decrease of touch and pain sensation in the right C6 and C7 segments. Painful dysesthesia was present in the left hand and right lower limb. The search for serum antibodies against GM1, GM2, GM3, GD1a, Gd1b, GQ1b, GA1, and GT1b was negative. No abnormality except mild cervical spondylotic changes was evident in the magnetic resonance imaging of the brain and spinal cord. The upper limb motor evoked potentials (MEPs) were not elicited by the left cortical stimulation and the central motor conduction time by the right cortical stimulation was remarkably prolonged in the upper limb MEPs. Nerve conduction study showed a delay of motor conduction velocity and distal latency in the right median and bilateral ulnar nerves with low amplitude and delayed velocity of sensory nerves of those nerves. Needle EMG revealed diffuse ongoing denervation potentials in bilateral upper limbs and giant motor unit potentials in the right triceps and first dorsal interossei muscles. These findings indicate that the delayed motor neuron syndrome induced by electrical shock is characteristic for having demyelination as well as axonal changes in both central and peripheral nervous systems.

Aged↗
PubMed2000

[A patient with motor neuron syndrome clinically similar to amyotrophic lateral sclerosis, presenting spontaneous recovery].

We report a patient with motor neuron syndrome similar to amyotrophic lateral sclerosis (ALS) and with spontaneous recovery. At the age 40, the woman developed progressive muscular weakness, atrophy and fasciculation in extremities. She also noted a dyspnea, tongue atrophy and dysphagia. A neurological examination 6 months after onset revealed i) a tongue atrophy and fasciculation, ii) diffuse muscule weakness and atrophy in face, neck and extremities, and iii) marked hyperreflexia in the four limbs and bilateral Babinski reflex, but iv) neither sensory disturbance nor ophthalmoplegia. Electromyogram (EMG) detected such denervation potentials as fibrillation potentials, fasciculation potentials, positive sharp waves and polyphasic or giant MUPs diffusely in the limb muscles. Peripheral nerve conduction study detected neither conduction block nor delay. Thus, she was diagnosed as suffering from ALS. However, since approximate 1 year after onset, her muscle weakness has gradually been getting better. Simultaneously, the dyspnea and dysphagia gradually improved. Two years after onset, an EMG examination detected chronic denervation potentials in the left musculus sternocleidomastoideus and a few on-going denervation potentials in the left musculus extensor carpi radialis, but no denervation potentials in other limb muscles. Fasciculation potentials were found in tongue muscles. Thus, the present case was thought to have a reversible motor neuron syndrome clinically quite similar to ALS. A mild increase in IgE (346 U/ml) and a low-titer IgM-class anti-GM1 antibody were found in her serum though its pathological significance was uncertain. Any immunological aberrance may account for the pathogenesis. It should be noted that clinically diagnosed cases of ALS may rarely recover spontaneously.

Adult↗
PubMed1999

Glutamate enhances phosphorylation of neurofilaments in cerebellar granule cell culture.

In amyotrophic lateral sclerosis (ALS), an abnormal increase of glutamate in the central nervous system indicates that it may play a key role in motor neuron death. The neuronal accumulation of phosphorylated neurofilaments (NFs) suggests an alteration of phosphorylation of NFs is also involved. Rat cerebellar granule cells (CGCs) are sensitive to glutamate neurotoxicity and provide a suitable model system for clarifying its mechanisms. Using cultured CGCs, we investigated the relationship between glutamate neurotoxicity and the phosphorylation of NFs. Because glutamate showed a dose-dependent neurotoxicity for CGCs, we adopted a 10 microM glutamate treatment, which produced no acute neurotoxicity during the experiments. The number of phosphorylated heavy subunits of neurofilaments (NF-Hs) increased to approximately twice that of the control after 72 h, although the total number of NF-Hs remained constant throughout the experiment. The phosphorylation of NF-Hs was significantly suppressed by the AMPA-receptor antagonist CNQX, but not by the NMDA-receptor antagonist MK-801. Our findings therefore suggest that exposure to a low concentration of glutamate enhances the phosphorylation of NF-Hs, mainly via the AMPA receptor.

Amyotrophic Lateral Sclerosis↗
PubMed1999

Glycosylphosphatidylinositol-anchored proteins play an important role in the biogenesis of the Alzheimer's amyloid beta-protein.

The Alzheimer's amyloid protein (Abeta) is released from the larger amyloid beta-protein precursor (APP) by unidentified enzymes referred to as beta- and gamma-secretase. beta-Secretase cleaves APP on the amino side of Abeta producing a large secreted derivative (sAPPbeta) and an Abeta-bearing C-terminal derivative that is subsequently cleaved by gamma-secretase to release Abeta. Alternative cleavage of the APP by alpha-secretase at Abeta16/17 releases the secreted derivative sAPPalpha. In yeast, alpha-secretase activity has been attributed to glycosylphosphatidylinositol (GPI)-anchored aspartyl proteases. To examine the role of GPI-anchored proteins, we specifically removed these proteins from the surface of mammalian cells using phosphatidylinositol-specific phospholipase C (PI-PLC). PI-PLC treatment of fetal guinea pig brain cultures substantially reduced the amount of Abeta40 and Abeta42 in the medium but had no effect on sAPPalpha. A mutant CHO cell line (gpi85), which lacks GPI-anchored proteins, secreted lower levels of Abeta40, Abeta42, and sAPPbeta than its parental line (GPI+). When this parental line was treated with PI-PLC, Abeta40, Abeta42, and sAPPbeta decreased to levels similar to those observed in the mutant line, and the mutant line was resistant to these effects of PI-PLC. These findings provide strong evidence that one or more GPI-anchored proteins play an important role in beta-secretase activity and Abeta secretion in mammalian cells. The cell-surface GPI-anchored protein(s) involved in Abeta biogenesis may be excellent therapeutic target(s) in Alzheimer's disease.

Alzheimer Disease↗
PubMed1999

Heightened IgE response to mite antigens in inflammatory neuropathies.

In order to clarify the IgE response to common environmental antigens, we measured the serum total IgE and allergen-specific IgE in 50 patients with Guillain-Barré syndrome (GBS), nine patients with Fisher syndrome (FS), 14 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 18 patients with mononeuritis multiplex (MNM), 43 patients with neurodegenerative disorders and 82 healthy controls by ELISA. The total IgE level was significantly higher in patients with GBS (median = 135 U/ml, P<0.05), CIDP (median = 175 U/ml, P<0.05) and MNM (median= 199 U/ml, P<0.05), than in the healthy controls (median = 79 U/ml), but not in those patients with neurodegenerative disorders. The specific IgE to Dermatophagoides pteronyssinus was significantly higher in the patients with GBS (56%, P<0.01) and MNM (72%, P<0.005) than in the healthy controls (32%). The level of specific IgE to Dermatophagoides farinae tended to be higher in the patients with GBS than in the healthy controls (0.05<P<0.1). The patients with CIDP and MNM also showed a similar increase in the frequency of mite antigen-specific IgE. As a result, the heightened IgE responses to mite antigens may therefore in part be related to the mechanism of inflammatory neuropathies. On the other hand, such heightened IgE responses in these inflammatory neuropathies may be a reflection of Th2 cell overactivity, which may induce an intense synthesis of autoantibodies against the peripheral nerves.

Adolescent↗
PubMed1999

Changes in the clinical phenotypes of multiple sclerosis during the past 50 years in Japan.

In order to clarify whether or not marked changes in the social environment during the past 50 years in Japan may have altered the clinical phenotypes of multiple sclerosis (MS), we retrospectively analyzed 143 consecutive patients with clinically definite MS who developed the disease between 1950 and 1997. Fifty-two patients were classified as Asian type MS showing a selective involvement of the optic nerves and the spinal cord, while 91 patients were considered to have Western type MS which demonstrated the involvement of multiple sites in the central nervous system including the cerebrum, cerebellum and brainstem. The ratio of Asian type versus Western type MS was 1:0.5 in the patients born in the 1920s and 1:1.27, 1:1.64 and 1:1.7 in those born in the 1930s, 1940s and 1950s, respectively, and thereafter it increased to 1:4.67 in those born in the 1960s and 1:4 in those born after the 1970s. As a result, the proportion of Asian type MS significantly decreased in the patients born after 1960 as compared with those born from 1930 to 1959 (P=0.0121). In the Asian type MS, the age of onset was significantly higher in the patients who developed the disease from 1985 to 1997 (42.4+/-13.5 years) than in those who developed the disease from 1950 to 1984 (32.3+/-12.4 years) (P=0.0149), while in the Western type MS no such change in the age of onset was observed. These findings suggest that the frequency of Asian type MS has apparently decreased in younger Japanese born after 1960 when Japan's rapid economic growth had just started, and environmental factors are therefore considered to contribute to determine the clinical phenotypes of MS in Asians.

Adult↗
PubMed1999

Ceramide induces apoptosis to immature cerebellar granule cells in culture.

A recent study revealed that ceramide acts as a second messenger in the sphingomyelin pathway and thus plays an important regulatory role in programmed cell death (apoptosis) to cell the lines induced by tumor-necrosis factor (TNF)-alpha and interleukin (IL)-1beta, although its effect remains controversial regarding primary neuronal culture. We investigated the effect of a cell-permeable ceramide analog (C2-ceramide) on cultures of cerebellar granule cells, which is thought to have active sphingomyelin pathway during development. The presence of C2-ceramide decreased the number of cerebellar granule cells (CGCs) in a concentration-dependent manner when added at DIV 1 (1 day in vitro). The ED50 was 60 microM. After DIV 2, CGCs became less sensitive to C2-ceramide and the ED50 was 200 microM at DIV 7. DNA staining with Hoechst 33258 showed the morphology of apoptotic nuclei in the degenerating neurons. Internucleosomal DNA degradation could also be observed by gel electrophoresis. Protein and RNA synthesis inhibitors prevented the death of neurons. C2-dihydroceramide, which lacks the 4-5 trans double bond and failed to induce neuronal death. These results thus demonstrated that C2-ceramide induces apoptosis to the CGCs at the early stage in vitro, however the CGCs were found to be less sensitive to C2-ceramide at the later stage in vitro.

Animals↗
PubMed1999

HLA-DPB1*0501-associated opticospinal multiple sclerosis: clinical, neuroimaging and immunogenetic studies.

In order to clarify the relationship between the clinical phenotype and the human leucocyte antigen (HLA) in multiple sclerosis in Asians, 93 Japanese patients with clinically definite multiple sclerosis underwent clinical MRI and HLA-DPB1 gene typing studies. According to a neurological examination, 29 patients were classified as opticospinal multiple sclerosis, 17 as spinal multiple sclerosis and 47 as Western type multiple sclerosis showing the involvement of multiple sites in the CNS including either the cerebrum, cerebellum or brainstem. The opticospinal multiple sclerosis showed a significantly higher age of onset, higher expanded disability status scale scores and higher CSF cell counts and protein content than the Western type multiple sclerosis. On brain and spinal cord MRI, the opticospinal multiple sclerosis showed a significantly lower number of brain lesions, but a higher frequency of gadolinium-enhancement of the optic nerve and a higher frequency of spinal cord atrophy than in Western type multiple sclerosis. The frequency of the HLA-DPB1*0501 allele was found to be significantly greater in opticospinal multiple sclerosis (93%) than in healthy controls (63%, corrected P value = 0.0091 and relative risk = 7.9), but not in Western type multiple sclerosis (66%) or spinal multiple sclerosis (82%). The marked differences in the clinical and MRI findings as well as in the immunogenetic backgrounds between the opticospinal multiple sclerosis and Western-type multiple sclerosis together suggest that HLA-DPB1*0501-associated opticospinal multiple sclerosis is a distinct subtype of multiple sclerosis.

Adult↗
PubMed1999

Adrenoleukodystrophy protein enhances association of very long-chain acyl-coenzyme A synthetase with the peroxisome.

OBJECTIVE: To clarify the function of adrenoleukodystrophy protein (ALDP) using our ALDP-deficient mice established by gene targeting. BACKGROUND: X-linked adrenoleukodystrophy (ALD) is characterized biochemically by the accumulation of very long-chain fatty acids (VLCFA) in tissues and body fluids, and is caused by impairment of peroxisomal beta-oxidation. In ALD, very long-chain acyl-coenzyme A synthetase (VLACS), which is necessary for peroxisomal beta-oxidation, does not function. METHODS: The ALDP-deficient mice and C57BL/6J mice were used. VLACS or ALDP were transiently expressed by lipofection in murine fibroblasts, and VLCFA beta-oxidation was assayed. Liver peroxisomes were purified by sequential centrifugations and a Nycodenz gradient centrifugation. The peroxisomal localization of VLACS was compared between the mutant and control mice using a Western blot analysis. RESULTS: Impairment of VLCFA beta-oxidation in ALDP-deficient fibroblasts was not corrected by the additional expression of VLACS alone but was by the coexpression of VLACS and ALDP. Although the tissue-specific expression of VLACS was similar in ALDP-deficient and normal mice, peroxisomal VLACS was clearly lower in ALDP-deficient than in normal mice. CONCLUSIONS: ALDP plays a role in the peroxisomal localization of VLACS, and VLACS does not function unless localized in the peroxisome.

ATP Binding Cassette Transporter, Subfamily D, Mem↗