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Biomedical subjects

M Osame

Publications and source records attributed to M Osame.

At least 307 records · Page 17Linked to original sources
PubMed1993

Experimental germanium dioxide-induced neuropathy in rats.

We report an experimental model of germanium dioxide (GeO2)-induced neuropathy in rats. More than 6 months administration of GeO2 to young rats produced neuropathy characterized by segmental demyelination/remyelination and nerve edema. Electron microscopic studies demonstrated that changes in Schwann cells, such as an increased cytoplasmic volume or disintegration of the cytoplasm, were the earliest pathological findings. Schwann cell mitochondria contained high electron-dense materials. Subsequent removal of necrotic Schwann cell debris and myelin by invading macrophages was evident. These findings suggested that the Schwann cells themselves are the primary target of the toxin. The deposition of electron-dense granules in the intra-axonal vesicles, which was suggestive of glycogen granules in mitochondria, was observed in the advanced stage of the neuropathy. The findings of endoneurial edema with splitting of myelin lamellae were noted at the early stage of demyelination. Nerve edema may be the result of GeO2-induced endothelial cell injury.

Animals↗
PubMed1993

Dominantly inherited motor and sensory neuropathy with excessive myelin folding complex.

The two patients in a family having the clinical and electrodiagnostic features of hereditary motor and sensory neuropathy (HMSN) are described. The main histological features of sural nerve were segmental demyelination and remyelination with moderate to marked loss of myelinated fibers, and myelin folding complex along all of the large and small myelinated fibers. These features appeared morphologically similar to those observed in HMSN with excessive myelin outfolding, or globular neuropathy. Southern blot analysis suggests that there were neither duplication nor deletion of the peripheral myelin protein-22 gene in the patients. The presented two patients may be a rare form of dominantly inherited HMSN with myelin folding complex.

Biopsy↗
PubMed1993

Chronic demyelinating neuropathy and intra-axonal polyglucosan bodies.

In this study we evaluated the relationship between polyglucosan bodies and peripheral nerve lesions. The biopsied sural nerve from a patient with late-onset chronic sensori-motor neuropathy showed many intra-axonal polyglucosan bodies and segmental demyelination/remyelination. The formation of Schwann cell hyperplasia around the demyelinated axons was found at the sites of polyglucosan bodies. These findings suggest that demyelinating neuropathy is a part of the spectrum of the diseases characterized by the accumulation of polyglucosan bodies within cellular compartments.

Aged↗
PubMed1993

Three cases of juvenile onset HTLV-I-associated myelopathy with pseudohypoparathyroidism.

Among 201 patients diagnosed with HAM/TSP at Kagoshima University, 21 juvenile onset patients had manifested clinical signs and symptoms at less than 15 years of age. They appeared to have common characteristics such as short stature and slight mental retardation. These signs prompted us to investigate five of them endocrinologically; and three patients with pseudohypoparathyroidism (PHP) were confirmed. Serum calcium levels were low, and human parathyroid hormone (PTH) infusion (Ellsworth-Howard test) caused low response in urinary cyclic AMP and phosphorus excretion. The first case had IgA nephropathy, which is generally associated with infectious diseases, while the second case had muscular lymphocytic infiltration. The mothers of cases 1 and 2, who were both seropositive for HTLV-I, were suspected to have abnormal calcium metabolism based on Ellsworth-Howard test. A brother of case 1 and two sisters of case 3 had also HAM/TSP and short stature. The early clinical onset of HAM/TSP may be due to PTH receptor anomaly and a low level of 1,25-dihydroxyvitamin D, which is deficient in PHP and is involved in the regulation of the immune response. The association with IgA nephropathy or myositis may result from progressive HTLV-I infection.

Adult↗
PubMed1993

Steroid-responsive myalgia in a patient with Becker muscular dystrophy.

We report a male patient with exercise-induced focal myalgia in the leg muscles. Dystrophin immunostaining of a biopsied muscle specimen from the patient showed the absence of or only faint immunoreactivity in 20% of the muscle fibers. The patient was diagnosed as having Becker muscular dystrophy. The myalgia was intractable and did not respond to non-steroidal anti-inflammatory drugs. The patient was placed on prednisone and found to be sensitive to it. Although he had recurrences of the symptom during tapering of the steroid, slower tapering over one year was tolerated. Steroid treatment may be useful for other Becker muscular dystrophy patients with myalgia.

Adult↗
PubMed1993

Treatment of cerebrotendinous xanthomatosis with low-density lipoprotein (LDL)-apheresis.

We studied the effects of LDL-apheresis on the biochemical and clinical abnormalities of 5 patients with cerebrotendinous xanthomatosis (CTX). Levels of both cholestanol and cholesterol decreased to approximately 60% of those of pretreatment after one perfusion and gradually returned to their initial levels within 2 weeks. Improvement of clinical manifestations and regression of Achilles tendon xanthomas were detected after several perfusions, though dramatic changes could not be recognized. EEG abnormalities were improved immediately after LDL-apheresis in one patient. We conclude that LDL-apheresis may affect the serum cholestanol level and clinical manifestations in patients with CTX.

Achilles Tendon↗
PubMed1993

Fluctuation of HTLV-I proviral DNA in peripheral blood mononuclear cells of HTLV-I-associated myelopathy.

To assess the immunopathological significance of the increased replication of human T-cell leukemia virus type I (HTLV-I) in HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) we investigated the dynamics of HTLV-I proviral DNA in peripheral blood mononuclear cells (PBMC) of HAM/TSP patients at different clinical stages. We compared the dynamics to those of asymptomatic HTLV-I carriers (AC). The estimation of the amount of HTLV-I proviral DNA was carried out by quantitative polymerase chain reaction of serially diluted DNA samples where it was feasible to titrate 0.04-80 copies per 100 PBMC. The proviral DNA quantified in six patients with HAM/TSP was 2-20 copies per 100 PBMC, while that in eight cases of AC was 0.04-8 copies per 100 PBMC. Thus, the amount of HTLV-I proviral DNA in HAM/TSP patients was 3-50 times as high as that of AC. When we followed up HAM/TSP patients for 1-3 years, the amount of HTLV-I proviral DNA fluctuated from 4 to 10-fold. These data suggest that the rate of HTLV-I replication increases in HAM/TSP and the amount of HTLV-I proviral DNA fluctuates in their clinical course. Fluctuation in the amount of HTLV-I proviral DNA may reflect dynamics of HTLV-I infected cell proliferation and immunological suppression in vivo in HAM/TSP patients.

Adult↗
PubMed1993

Anti-lymphocyte antibodies and circulating immune complexes in the sera of patients with myelopathy associated with human T lymphotropic virus type-I.

We measured levels of circulating immune complexes in the human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) by Raji cell assay and C1q binding assay using an enzyme-linked immunosorbent assay (ELISA). The levels of anti-lymphocyte antibody were also measured using normal donor peripheral blood T-lymphocytes. The levels of anti-lymphocyte antibodies were significantly higher in the sera of patients with HAM compared to controls (P < 0.01). The concentrations of immune complexes measured by Raji cell assay were also significantly higher in the HAM patients' sera than in controls. However, when levels of immune complexes were measured by C1q binding assay, there was no significant difference between HAM patients and controls. There was no significant difference in the levels of anti-lymphocyte antibodies and immune complexes between HTLV-I carriers and controls. Circulating immune complexes detected by the Raji cell assay did not include HTLV-I p-19 as detected by the indirect immunofluorescent method. Levels of anti-lymphocyte antibody were correlated with levels of circulating immune complexes as detected by the Raji cell assay in the sera of patients with HAM. These findings indicate that anti-lymphocyte antibodies and circulating immune complexes are present in the sera of HAM patients, and that the levels of complexes detected by Raji cell assay may reflect anti-lymphocyte antibody levels.

Adult↗
PubMed1993

Benign monoclonal T cell proliferation in HTLV-I infection.

A spectrum of carrier states in human T lymphotropic virus type-I (HTLV-I) infection is proposed. The suspected process of clonal selection of HTLV-I infected cells results in the spectrum of nonfatal states from polyclonal to monoclonal virus integration. This idea is based on the discovery that monoclonal proviral HTLV-I DNA was detected in the fresh peripheral blood lymphocytes from some patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a nonfatal chronic neurological disorder.

Carrier State↗
PubMed1993

Degradative activity of granzyme A on skeletal muscle proteins in vitro: a possible molecular mechanism for muscle fiber damage in polymyositis.

The importance of cytotoxic T lymphocytes (CTLs) in the autoimmune inflammatory myopathies, especially polymyositis (PM), has been emphasized. We have studied the degradative activity of granzyme A, a cytotoxic molecule with trypsin-like specificity in CTL granules, on several muscle proteins in vitro. Our study reveals that granzyme A hydrolyzes dystrophin, myosin, and nebulin, but not laminin, alpha-actinin, vinculin, and connectin in vitro. Among these proteins, nebulin is more susceptible to proteolysis, followed by dystrophin, myosin heavy chain, and myosin light chains, in that order. This result implies an important role of granzyme A in CTL-mediated muscle fiber damage in PM.

Amino Acid Sequence↗
PubMed1993

Limited sequence divergence of HTLV-I of Indian HAM/TSP patients from a prototype Japanese isolate.

Nucleotide sequences of two HTLV-I proviruses isolated from Indian patients with HAM/TSP were analyzed. The sequence data of the env, pX, and LTR regions showed 98-99% homologies with the prototype HTLV-I, ATK-1, isolated from a Japanese ATL patient, indicating that HTLV-I isolates in India and Japan are similar, with minor variations. However, certain small sequences of noncoding regions in the pX and LTR showed differences of 6.1 and 7.2%, respectively, thus the conclusion could vary depending on the regions and length of the sequences used for comparison.

Adult↗
PubMed1993

Immunocytochemical analysis of the cellular infiltrate in the spinal cord lesions in HTLV-I-associated myelopathy.

Immunocytochemical staining of spinal cords from five autopsied patients with HAM/TSP was performed using a panel of monoclonal antibodies reactive with T cells. T cell subsets, B cells, macrophages, natural killer cells, IL-2 receptor-positive cells, and HLA-ABC and HLA-DR. In the spinal cords of patients with a shorter duration of illness, CD4+ cells, CD8+ cells and macrophages were evenly distributed in active-chronic inflammatory lesions. In striking contrast, we noted the predominance of CD8+ cells over CD4+ cells in the inactive-chronic inflammatory lesions of patients with longer duration of illness. Natural killer cells, IL-2 receptor-positive cells and B cells were only rarely present in both the active-chronic and inactive-chronic lesions. HLA-ABC was positive in endothelial cells and infiltrating mononuclear cells, and HLA-DR was positive in endothelial cells, microglia and infiltrating mononuclear cells. This study suggests that immune responses in the spinal cord lesions of HAM patients gradually change along with the duration of illness.

Aged↗
PubMed1993

Werner's syndrome associated with spastic paraparesis and peripheral neuropathy.

A Werner's syndrome patient with spastic paraparesis and polyneuropathy had slowing of central and peripheral nerve conduction. Sural nerve biopsy revealed a significantly higher frequency of demyelination and remyelination and a loss of myelinated fibers. These data suggest that the central and peripheral nervous systems are affected in Werner's syndrome.

Adult↗