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Biomedical subjects

M Osame

Publications and source records attributed to M Osame.

At least 37 records · Page 2Linked to original sources
PubMed2002

In vivo induction of human immunodeficiency virus type 1 entry into nucleus-free cells by CD4 gene transfer to hematopoietic stem cells: a hypothetical possible strategy for therapeutic intervention.

As a useful alternative to employing soluble CD4 to inhibit binding of human immunodeficiency virus type 1 (HIV-1) to target cells, the introduction of CD4-bearing erythrocyte has been proposed by two study groups (see Refs. (5,6)). Prominently, Nicolau and colleagues demonstrated that the electroinserted CD4 molecules in the membranes of erythrocytes are capable of mediating HIV-1 entry. The implications of the studies are that inactivation of the integration-dependent retrovirus by the facilitation of entry into the nucleus-free cells, referred to as 'fake host trap' or 'host cell decoy', may be a possible therapeutic approach. Here we expand this concept to include genetic modification of autologous hematopoietic stem cells and review the relevant theoretical basis. Effective application of molecular technologies to induce partial replacement of hematopoiesis may be critical for this strategy.

CD4 Antigens↗
PubMed2002

Phenotypes and mitochondrial DNA substitutions in families with A3243G mutation.

OBJECTIVE: To clarify the relationship between mitochondrial DNA (mtDNA) sequence variations and phenotypes in patients with A3243G mutation. MATERIALS AND METHODS: We studied whole mtDNA sequences in two families with A3243G mutation and characteristic clinical features. Two brothers in Family 1 had shown thiamine deficiency and mitochondrial myopathy without central nervous system involvement. In Family 2, a 16-year-old woman showed the symptoms of mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Her mother had had diabetes mellitus and died at the age of 42. The proportion of A3243G mtDNA in blood was 87 and 89% in the patients of Family 1, and 25% in the patient and less than 5% in the mother of Family 2. RESULTS: The mtDNA analysis revealed the following homoplasmic substitutions: T1520C and C12153T found only in Family 1, and A15954G found only in Family 2. These substitutions were not detected in seven other MELAS patients or in 50 controls. CONCLUSION: These substitutions might be specific to these families and could be one of the factors that modulate their clinical features together with the A3243G mutation.

Adolescent↗
PubMed2002

A comparative study of eicosanoid concentrations in sputum and urine in patients with aspirin-intolerant asthma.

BACKGROUND: Although many studies have assumed that the overproduction of cysteinyl- leukotrienes (cys-LTs) and an imbalance of arachidonic acid metabolism may be plausible causes for the pathogenesis of aspirin-intolerant asthma (AIA), there has been little experimental evidence to substantiate this notion in lower airways of patients with AIA. OBJECTIVES: The purpose of this study was to compare the eicosanoid concentrations in sputum and urine from patients with AIA. METHODS: The concentrations of sputum cys-LTs, prostaglandin E2 (PGE2), PGF2alpha, PGD2 and thromboxane B2 were measured to assess local concentrations of eicosanoids in patients with AIA and in those with aspirin-tolerant asthma (ATA). The concentrations of two urinary metabolites, leukotriene E4 (LTE4) and 9alpha11betaPGF2, were also measured to corroborate the relationship between the eicosanoid biosynthesis in the whole body and that in lower airways. RESULTS: The concentration of PGD2 in sputum was significantly higher in patients with AIA than in those with ATA (median, 5.3 pg/mL vs. 3.1 pg/mL, P < 0.05), but there was no significant difference in the concentration of the corresponding metabolite, 9alpha11betaPGF2, between the two groups. No differences were noted in the concentrations of other prostanoids in sputum between the two groups. The sputum cys-LT concentrations showed no differences between the two groups, in spite of the observation that the concentration of urinary LTE4 was significantly higher in patients with AIA than in those with ATA (median, 195.2 pg/mg-cre vs. 122.1 pg/mg-cre, P < 0.05). There was a significant correlation among the concentration of cys-LTs, the number of eosinophils and the concentration of eosinophil-derived neurotoxin (EDN) in sputum. CONCLUSION: The urinary concentration of LTE4 does not necessary reflect cys-LT biosynthesis in lower airways. A significantly higher concentration of PGD2 in sputum from patients with AIA suggests the possible ongoing mast cell activation in lower airways.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

HLA-A*26, HLA-B*4002, HLA-B*4006, and HLA-B*4801 alleles predispose to adult T cell leukemia: the limited recognition of HTLV type 1 tax peptide anchor motifs and epitopes to generate anti-HTLV type 1 tax CD8(+) cytotoxic T lymphocytes.

Genetic risk for adult T cell leukemia (ATL) has been implicated by ethnic and familial segregation of ATL patients from HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). To clarify the genetic risk for ATL, we characterized HLA class I alleles of ATL patients and analyzed the anchor motifs of HTLV-1 peptides binding to HLA class I molecules, using 291 lines of anti-HTLV-1 CD8(+) cytotoxic T lymphocytes (CTLs) generated in vitro with a total of 165 synthetic peptides for HTLV-1 Tax and Env proteins. Allele frequencies of HLA-A*26, B*4002, B*4006, and B*4801 were significantly higher in ATL patients than in HAM/TSP patients and asymptomatic HTLV-1 carriers in southern Japan. CD8(+) CTL analysis revealed the HTLV-1 Tax peptide sequence to completely lack anchor motifs of peptides binding to HLA-A*26,B*4002, and B*4006 molecules but to possess one anchor for HLA-B*4801, while the HTLV-1 Env peptide sequence had many anchor motifs for HLA-A*26, B*4002, B*4006, and B*4801 molecules. Most ATL patients featured heterozygous HLA class I alleles composed of HLA-A*26, B*4002, B*4006, and B*4801, with a lower number of HTLV-1 Tax peptide anchor motifs and epitopes generating anti-HTLV-1 Tax CD8(+) CTLs than individuals possessing other HLA alleles. The relationship between Tax epitope and ATL incidence was verified by the significantly decreased number of HTLV-1 Tax epitopes in ATL patients compared with asymptomatic HTLV-1 carriers (p < 0.01) as well as late onset ATL patients (p < 0.001). These results indicate that HLA-A*26, B*4002, B*4006, and B*4801 alleles predispose to ATL because of the limited recognition of HTLV-1 Tax peptide anchor motifs and epitopes capable of generating anti-HTLV-1 Tax CD8(+) CTLs.

Adult↗
PubMed2001

Cytotoxic T-cell abundance and virus load in human immunodeficiency virus type 1 and human T-cell leukaemia virus type 1.

The correlation between virus load and specific cytotoxic T-lymphocyte (CTL) frequency during the chronic phase in human immunodeficiency virus type 1 (HIV-1) infection has been found to be negative in cross-sectional studies. We report here that, in infection with the related retrovirus human T-cell leukaemia virus type 1 (HTLV-1), the correlation is positive in asymptomatic carriers and zero in patients with the associated inflammatory disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We demonstrate that the direction of the correlation may depend on the efficacy of the CTL response using mathematical models. We conclude that the CTL response is effective in asymptomatic carriers of HTLV-1, but ineffective in patients with HAM/TSP. Virus-mediated impairment of specific CTL production in HIV-1 infection can account for the negative correlation observed.

Carrier State↗
PubMed2001

Involvement of enhanced sensitivity of N-methyl-D-aspartate receptors in vulnerability of developing cortical neurons to methylmercury neurotoxicity.

The developing cortical neurons have been well documented to be extremely vulnerable to the toxic effect of methylmercury (MeHg). In the present study, a possible involvement of N-methyl-D-aspartate (NMDA) receptors in MeHg neurotoxicity was examined because the sensitivity of cortical neurons to NMDA neurotoxicity has a similar developmental profile. Rats on postnatal day 2 (P2), P16, and P60 were orally administered MeHg (10 mg/kg) for 7 consecutive days. The most severe neuronal damage was observed in the occipital cortex of P16 rats. When MK-801 (0.1 mg/kg), a non-competitive antagonist of NMDA, was administered intraperitoneally with MeHg, MeHg-induced neurodegeneration was markedly ameliorated. Furthermore, there was a marked accumulation of nitrotyrosine, a reaction product of peroxynitrite and L-tyrosine, after chronic treatment of MeHg in the occipital cortex of P16 rats. The accumulation of nitrotyrosine was also significantly suppressed by MK-801. In the present electrophysiological study, the amplitude of synaptic responses mediated by NMDA receptors recorded in cortical neurons of P16 rats was significantly larger than those from P2 and P60 rats. These observations strongly suggest that a generation of peroxynitrite through activation of NMDA receptors is a major causal factor for MeHg neurotoxicity in the developing cortical neurons. Furthermore, enhanced sensitivity of NMDA receptors may make the cortical neurons of P16 rats most susceptible to MeHg neurotoxicity.

Age Factors↗
PubMed2001

Expression of vascular endothelial growth factor in tuberculous meningitis.

The pathogenesis of tuberculous meningitis is still unclear. Recently, vascular endothelial growth factor (VEGF) was found to be associated with inflammatory diseases and we found the increased serum level of VEGF in pulmonary tuberculosis. We hypothesized that VEGF might be associated with the pathogenesis of tuberculous meningitis and measured serum and cerebrospinal fluid (CSF) levels of VEGF in 28 patients with tuberculous meningitis and 31 non-tuberculous infectious meningitis patients (13 bacterial meningitis patients, eight fungal meningitis patients and 10 patients with viral meningitis) before therapy. We examined the CSF VEGF levels 3 months after in 12 tuberculous meningitis patients. The serum and CSF levels of VEGF were significantly higher in tuberculous meningitis than in other meningitis. The decrease in titer of CSF VEGF paralleled the clinical improvement of tuberculous meningitis. Immunohistochemical staining of autopsied brains demonstrated the presence of VEGF in the inflammatory mononuclear cells of the dense fibroconnective tissue both in the subarachnoid space and surrounding the vasculitis lesion. We found the expression of VEGF in tuberculous meningitis and think that VEGF reflects its activity.

Adolescent↗
PubMed2001

Circulating levels of MMP-1, -2, -3, -9, and TIMP-1 are increased in POEMS syndrome.

The authors quantitatively measured levels of matrix metalloproteinases (MMP), tissue inhibitor of metalloproteinases (TIMP), and vascular endothelial growth factor (VEGF) in blood samples of POEMS syndrome. Circulating levels of MMP-1, -2, -3, -9, and TIMP-1 were more increased in patients with POEMS syndrome than in patients with other neurologic disorders or in healthy controls. Serum levels of VEGF and TIMP-1 were strongly correlated with each other. Increased circulating levels of MMP-1, -2, -3, -9, and TIMP-1 may lead to a better understanding the pathogenesis of POEMS syndrome.

Endothelial Growth Factors↗
PubMed2001

Clinical phenotype in X-linked Charcot-Marie-Tooth disease with an entire deletion of the connexin 32 coding sequence.

To clarify the clinical phenotype and molecular mechanism in X-linked Charcot-Marie-Tooth disease (CMTX) patients with a deletion of the whole connexin 32 (Cx32) coding sequence, we studied a family with this deletion by electrophysiology, Southern blotting and quantitative PCR analyses. Two brothers with no copy of Cx32, 27 and 25 years old, showed steppage gait, moderate muscle atrophy and weakness, and mild sensory disturbance in the distal parts of the legs. The clinical phenotypes in these brothers were not different from those in patients with other types of severe Cx32 mutations. Their mother, with one copy of Cx32, showed very mild muscle weakness and sensory disturbance. An electrophysiological study showed a nonuniform demyelinating neuropathy with some aspects of an axonal-loss neuropathy. Sural nerve biopsy showed loss of myelinated fibers, many relatively thin myelin sheaths, clusters of small myelinated fibers, and some onion bulb formations. The present findings suggest that both a demyelinating process and an axonal involvement were present in the patients with total defect of Cx32 probably due to loss of the function mechanism of Cx32 as the underlying molecular mechanism, because a dominant negative effect theory is not applicable in these patients.

Adult↗
PubMed2001

Intraventricular administration of the neurotrophic factor midkine ameliorates hippocampal delayed neuronal death following transient forebrain ischemia in gerbils.

Midkine (MK) is a growth factor with neurotrophic activities, and is expressed during the early stages of experimental cerebral infarction in rats in the zone surrounding the infarct. To evaluate in vivo activity of MK in preventing neuronal death, MK produced in yeast (Pichia pastoris) was administered into the brain ventricle immediately before occlusion of the bilateral common carotid artery of Mongolian gerbils. MK administration at the dose of 0.5-2 microg immediately before occlusion was found to ameliorate delayed neuronal death in the hippocampal CA1 region caused by transient ischemia 7 days after the insult. The hippocampal neurons of the MK-administered gerbils tended to degenerate 14 and 21 days after the insult, but their numbers remained higher than those in saline-administered controls; however, the hippocampal neurons were degenerated 28 days after the insult. MK administration at 2 h after occlusion did not ameliorate the neuronal death. These findings suggested that the therapeutic time window was narrow. The two to four times repeated administration of 2 microg MK immediately before and at 1, 2, or 3 weeks after the occlusion were not significantly different for the hippocampal neuronal death at 28 days after the insult compared with a single injection, but were significantly effective compared with vehicle administration alone. These findings suggested that the therapeutic time window was relatively narrow. The potent neuroprotective activity of MK observed in vivo suggested that MK might be useful as a therapeutic reagent for prevention of neuronal death in neurodegenerative diseases.

Animals↗
PubMed2001

Phenotypic variation in a large Japanese family with Miyoshi myopathy with nonsense mutation in exon 19 of dysferlin gene.

Miyoshi myopathy, an autosomal recessive muscular dystrophy involving distal muscles, is caused by dysferlin mutations. We present clinical and genetic studies of two men and six women, aged 25-83 years, from a Japanese family with consanguineous marriages. Onset was between ages 17 and 59 years. Six of the patients had muscle involvement typical of Miyoshi myopathy, one initially had severe proximal muscle involvement, and one had scapuloperoneal-type muscle involvement. Three patients showed steppage gait. Genetic linkage analysis identified a maximum lod score of 3.34 (&theta;=0.00) at marker D2S292 in 2p13. Analysis of dysferlin revealed the mutation G2090T (Glu573Stop) in exon 19 in all affected patients. This is the largest Japanese family with Miyoshi myopathy showing intrafamilial phenotypic variation and sharing a common mutation in dysferlin.

Adult↗
PubMed2001

Existence of escape mutant in HTLV-I tax during the development of adult T-cell leukemia.

Although Tax protein is the main target of cytotoxic T lymphocyte (CTL) on human T-cell lymphotropic virus type I (HTLV-I)-infected cells, and Tax peptide 11 through 19 binding to HLA-A*02 has been shown to elicit a strong CTL response, there are patients with adult T-cell leukemia (ATL) bearing HLA-A*02. To explore whether there is genetic variation in HTLV-I tax that can escape CTL recognition during the development of ATL, the HTLV-I tax gene was sequenced in 55 patients with ATL, 61 patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and 62 healthy carriers, and it was correlated with the presence of HLA-A*02. First, a premature stop codon in the 5' half of the tax gene that looses transactivation activity on the viral enhancer was observed in 3 patients with acute and 1 patient with chronic ATL. This stop codon was revealed to emerge after the viral transmission to the patient from sequence analysis in family members with ATL. Second, amino acid change in Tax peptide 11-19 was observed in 3 patients with ATL. CTL assays demonstrated that this altered Tax 11-19 peptide, observed in ATL patients with HLA-A*02, was not recognized by Tax 11-19-specific CTL. Two patients with ATL had large deletions in tax by sequencing, and 5 patients with ATL had deletions in HTLV-I by Southern blotting. These findings suggest that at some stage of ATL development, HTLV-I-infected cells that can escape the host immune system are selected and have a chance to accumulate genetic alterations for further malignant transformation, leading to acute ATL.

Codon, Terminator↗
PubMed2001

HTLV-1-associated myelopathy/tropical spastic paraparesis with pseudohypoparathyroidism.

In many short-stature patients with human T-lymphotrophic virus type I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), signs and symptoms were manifested during childhood. Successive investigations revealed 12 of 14 short-stature patients with pseudohypoparathyroidism (PHP) from the findings of short metacarpi, parathyroid hormone infusion test, immunoblotting of erythrocyte membrane, or lymphocytic Northern blotting of Gsalpha. Patients with PHP probably showed HAM/TSP based on their modified immunologic status. Human T-lymphotrophic virus type I infection did not induce PHP, but PHP may be a risk factor for the occurrence of HAM/TSP.

Adolescent↗
PubMed2001

Frameshift mutation in the collagen VI gene causes Ullrich's disease.

Patients with Ullrich's disease have generalized muscle weakness, multiple contractures of the proximal joints, and hyperextensibility of the distal joints. Recently, we found a deficiency of collagen VI protein in two patients with Ullrich's disease. In this study, we detected a homozygous 26 bp deletion in exon 14 of the collagen VI alpha 2 gene (COL6A2) in one patient. This mutation causes a frameshift and a premature termination codon, and results in a truncated collagen VI alpha 2 chain. Our data suggest that at least some cases of Ullrich's disease result from recessive mutations in COL6A2.

Adult↗
PubMed2001

Phenotypes of X-linked Charcot-Marie-Tooth disease and altered trafficking of mutant connexin 32 (GJB1).

To clarify the pathomechanism in three patients with X-linked Charcot-Marie-Tooth disease (CMTX) and unique clinical features, we studied three connexin (Cx) 32 (GJB1) mutants with respect to cellular localization in cultured cells. Wild-type Cx32 and three Cx32 mutants (Va163Ile and Glu186Lys, obtained from CMTX patients with hearing impairment; and Arg22Gln, obtained from a CMTX patient with a fair number of onion-bulb formations) were transfected to rat pheochromocytoma cells (PC12). We investigated the expression of Cx32 protein in each clone by immunoblotting and immunohistochemical staining. While Cx32 protein with the Arg22Gln mutation was detectable immunohistochemically only in the cytoplasm, Cx32 protein with the Va163Ile or Glu186Lys mutation was detected in both the plasma membrane and the cytoplasm. Cx32 protein with the wild-type sequence was detected mostly in the plasma membrane, with plaques indicating the existence of active gap junction formation. These three Cx32 mutations associated with CMTX patients with unique clinical and pathological findings caused altered trafficking of the Cx32 protein. These altered expressions indicated loss of active gap junction formation with different expression abnormalities in these CMTX patients.

Animals↗
PubMed2001

Machado-Joseph disease with retinal degeneration and dementia.

OBJECTIVES: To clarify the phenotypic varieties in Machado-Joseph disease (MJD). MATERIALS AND METHODS: We studied a 64-year-old man with ataxia, retinal degeneration and dementia neurologically, ophthalmologically and genetically. RESULTS: The patient noted dysesthesia of his hands at age 57 and later had memory disturbance. He had gait disturbance and needed a wheelchair at age 64. His total IQ was 61 on the WAIS-R. He had loss of central vision, ophthalmoplegia, hearing impairment, dysarthria, truncal and limb ataxia, sensory disturbance, and mild weakness of the extremities. Electrophysiologically he was suspected to have polyneuropathy. Brain MRI showed marked atrophy of the cerebellum and pons with mild cerebral atrophy. Ophthalmologic evaluation revealed multiple chorioretinal atrophy. Expanded CAG repeat numbers in MJD1 were 64. CONCLUSION: These findings indicate that the clinical features of MJD might cover a wider spectrum than previously expected, though it is possible that these complications, namely retinal degeneration and dementia, were incidental findings in this patient.

Brain↗
PubMed2001

HTLV-I proviral load correlates with progression of motor disability in HAM/TSP: analysis of 239 HAM/TSP patients including 64 patients followed up for 10 years.

To clarify clinical and laboratory findings that may be related to the pathomechanism of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we analyzed these findings in 239 patients with HAM/TSP, including 64 patients followed up for 10 years after their first examinations, with special interest in the HTLV-I proviral load in peripheral blood mononuclear cells (PBMCs). The proviral load in PBMCs did not differ in terms of modes of HTLV-I transmission. However, the proviral load in patients with age of disease onset greater than 65 years tended to be higher than those with a younger age of onset. In the 64 patients followed up for 10 years, the clinical symptoms deteriorated in 36 patients (56%), unchanged in 26 patients (41%), and improved in 2 patients (3%). HTLV-I proviral load also appeared to be related to the deterioration of motor disability in these patients. To our knowledge, the present study is the first longitudinal study concerning the relationship between the clinical course of HAM/TSP and HTLV-I proviral load. It is suggested that HTLV-I proviral load is related to the progression of motor disability and is an important factor to predict prognosis of patients with HAM/TSP.

Age of Onset↗