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Biomedical subjects

J Kira

Publications and source records attributed to J Kira.

At least 145 records · Page 8Linked to original sources
PubMed1997

A novel monoclonal antibody which reacts with a high molecular weight neuronal cytoplasmic protein and myelin basic protein (MBP) in a patient with macroglobulinemia.

We report on the case of a 70-year-old man with primary macroglobulinemia who showed cranial polyneuropathy and extensive radiculoneuropathy. His serum contained an IgM lambda monoclonal antibody which reacted with both a high molecular weight protein in grey matter and purified myelin basic protein (MBP) on immunoblotting. In an immunohistochemical study, strong immunoreactivity was detected only in the cytoplasm of neurons and weak immunoreactivity was detected in myelin. These findings suggest that this antibody may be related to the pathogenesis of neuronal damage in patients with macroglobulinemia.

Aged↗
PubMed1997

Long-term, high dose interferon-alpha treatment in HTLV-I-associated myelopathy/tropical spastic paraparesis: a combined clinical, virological and immunological study.

The efficacy of long-term, high dose interferon-alpha (IFN-alpha) therapy was studied in seven patients with HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). IFN-alpha was administered at a dose of 6 x 10(6) international units daily for the initial 2 weeks and thereafter 3 times a week for the following 22 weeks. Five patients showed a sustained improvement in motor performance during and up to 6 months after the completion of IFN-alpha. The other patient who responded to IFN-alpha initially dropped out at 3 months because of depression, while another patient first deteriorated and thereafter dropped out. In the six responders, the absolute number of peripheral blood lymphocytes (PBL) harboring the HTLV-I genome as evaluated by the quantitative polymerase chain reaction method decreased significantly during the therapy period (28.6 +/- 16.6% reduction, P = 0.0083), whereas the one deteriorated patient showed a 2.5-fold increase in HTLV-I-infected cells. The autoproliferation of CD4+ T clone cells from a single cell culture was markedly depressed even after the cessation of IFN-alpha in the responders who completed long-term IFN-alpha therapy. In addition, the CD8+DR+ T cells in the peripheral blood and soluble IL-2 receptor levels in the sera increased significantly during the therapy in all patients (P = 0.0431 and P = 0.0041, respectively). Therefore, the results of our study suggested that both the reduction of HTLV-I proviral DNA load and immunomodulation by long-term IFN-alpha therapy contributed to its sustained clinical benefits.

Adult↗
PubMed1997

An association of human T-cell lymphotropic virus type I infection with vascular dementia.

Subjects ranging in age from 50 to 89 years old, either with or without dementia were studied by both ELISA for anti-human T-cell lymphotropic virus type I (HTLV-I) gag 100-130 antibody and by cranial CT in order to clarify the relationship between HTLV-I infection and dementia. The frequency of anti-HTLV-I antibody was found to be significantly higher in the patients with dementia (24/130, 18.5%) than in those without dementia (11/139, 7.9%) (P=0.0169). Among the various types of dementia, HTLV-I seropositivity was found to be significantly associated with vascular dementia (11/48, 23%) (P=0.0087), but not with Alzheimer type dementia. In addition, HTLV-I seropositivity was also associated with Babinski sign, and the severity of cerebral infarction, ventricular dilatation and periventricular lucency on CT. The presence of HTLV-I therefore appears to be one of the risk factors for vascular dementia in HTLV-I endemic areas.

Adult↗
PubMed1997

Primary human immunodeficiency virus type 1 viremia and central nervous system invasion in a novel hu-PBL-immunodeficient mouse strain.

We established four new mouse strains with defective T and B cells as well as defects in innate immunological reactions using an NK cell depletion antibody and showed that all mutant mouse strains efficiently received human peripheral blood leukocyte (PBL) engraftment (hu-PBL-scid mice). Higher levels of human immunodeficiency virus type 1 (HIV-1) replication were observed in these new hu-PBL-scid mice than in conventional hu-PBL-C.B-17-scid mice. In one particular strain, hu-PBL-NOD-scid mice, high levels of HIV-1 viremia (more than 10(6) 50% infectious doses per ml) were detected after infection with HIV-1. The plasma viral load was about 100 to 1,000 times higher than that observed in other hu-PBL-scid mice infected with HIV-1. Although high-level viremia did not correlate with the total amount of HIV-1 RNA in cells from infected mice, high levels of free virions were detected only in hu-PBL-NOD-scid mice. HIV-1 viremia induced systemic HIV-1 infection involving the liver, lungs, and brain. PCR in situ hybridization confirmed that HIV-1-infected cells invaded the brain tissue of the hu-PBL-NOD-scid mice. Our results suggest that the genetic background, including innate immunity, is critical in the development of primary HIV-1 viremia and subsequent central nervous system invasion with HIV-1. The hu-PBL-NOD-scid mouse represents a useful model for the study of the pathogenesis of HIV-1 in vivo, especially brain involvement, and therapy of primary HIV-1 viremia.

Animals↗
PubMed1997

[Myelopathy due to vitamin B12 deficiency presenting only sensory disturbances in upper extremities: a case report].

We report a 54-year-old man with vitamin B12 deficiency myelopathy limited to the upper extremity region. He was well until October, 1995, when he had an onset of exertional dyspnea and general fatigue. Then he noted tingling sensation in bilateral upper extremities in March, 1996. He had undergone total gastrectomy due to gastric ulcer 15 years ago. Neurological examination revealed superficial and vibratory sensory loss in the upper extremities distal to elbows, and pseudoathetoid movement of the left fingers. Otherwise neurological examination was unremarkable. Laboratory examination revealed macrocytic anemia, and low serum vitamin B12. However, serum folate was within the normal range. In SEP studies, median nerve stimulation evoked peripheral N9 and N13 potentials, but not cortical N20 one. Posterior tibial nerve stimulation elicited normal responses. MEP, VEP, needle EMG, and nerve conduction studies gave normal findings. T2-weighted MRI showed high signal intensity lesions at the C1-Th1 level in the posterior column, especially in the cuneate fascicles. The gracile fascicles were spared. This is a very rare case of myelopathy due to vitamin B12 deficiency presenting only sensory disturbances in both upper extremities. The lesions limited in the cuneate fascicle were confirmed by electrophysiological, and neuroradiological examinations.

Arm↗
PubMed1997

Bilateral striate cortex contusion presenting with cerebral asthenopia rather than cortical blindness.

We report a 22-year-old female with a history of contusion of bilateral occipital lobes at the age of 1 year. Magnetic resonance imaging confirmed severe lesion in bilateral striate cortices which should have resulted in cortical blindness. However, she displayed a fairly good visual function presenting only cerebral asthenopia and the restriction of the visual field. A positron emission tomography revealed that no areas other than the primary visual cortices responded to visual stimuli. Thus, her residual vision may be attributable to plasticity of the visual cortex in humans.

Adult↗
PubMed1997

[Molecular analysis of a patient with carnitine palmitoyltransferase II deficiency].

Carnitine palmitoyltransferase (CPT), one of the key enzymes of beta-oxidation, translocates long-chain fatty acids from the cytosolic compartment into the mitochondrial matrix to undergo beta-oxidation. Recently, the CPT system has been characterized to consist of two distinct mitochondrial membrane-bound enzymes, CPT I, located on the inner side of the outer mitochondrial membrane, and CPT II, located on the inner mitochondrial membrane. We have investigated a Japanese patient with muscular manifestations who was previously reported as CPT deficiency. Enzymatic analysis of her cultured lymphoblasts revealed that CPT II activity was reduced to 5.8%, indicating that the patient suffered from CPT II deficiency. Molecular analysis identified a missense mutation, a glutamate (174)-to-lysine substitution (E174K), in the CPT II cDNA. The patient was homozygous for the mutation. The presence of the mutation was confirmed by PCR-RFLP with a mismatched primer to generate Mbo II recognition sequence at the mutation site. It has been reported that CPT II deficiency manifests as two different clinical phenotypes: a muscular form and a hepatocardiomuscular form. To our knowledge, this is the first case of CPT II deficiency with muscular symptoms to be characterized by molecular analysis in Japan.

Carnitine O-Palmitoyltransferase↗
PubMed1996

Electron-transfer function of NAD+-immobilized alginic acid.

Polymerized NAD+ (Alg-NAD+) was prepared and its electrochemical properties were investigated. NAD+ has been covalently immobilized at the carboxyl group of alginic acid using water soluble carbodiimide (EDC) and then Alg-NAD+s of various NAD+ density were obtainable depending on NAD+ concentration in the reaction mixture. Absorbance of 260 nm of Alg-NAD+s showed that 3.4 to 17.6% of carboxyl groups of alginic acid were coupled with NAD+. The coenzyme activity of immobilized NAD+ has reached 80 to 90% on each Alg-NAD+. A cathodic peak in the cyclic voltammogram of Alg-NAD+ appeared at -1.2 V (vs. SCE) corresponding to the reduction wave of free NAD+. The anodic wave of NAD dimer was not observed in the presence of 2.0 mM methyl viologen and 5 units of diaphorase and NAD+ immobilized on the composite electrode could be reduced to the normal NADH. The ratio of apparent diffusion coefficient (Dapp.) of Alg-NAD+ and free NAD+ was evaluated from the variation of ipc with the square root of sweep rate (v 1/2). Despite the high molecular weight of Alg-NAD+, Dapp. Alg-NAD+/Dapp. free NAD+ are larger than that expected. These results indicate that electron transfer occurred effectively between each NAD+ molecule immobilized onto the polymer chain. It is also confirmed by a conjugated redox enzyme reaction with Alg-NAD+.

Alginates↗
PubMed1996

Western versus Asian types of multiple sclerosis: immunogenetically and clinically distinct disorders.

The polymorphism of HLA-DRB1, -DRB3, and -DRB5 genes as well as magnetic resonance images of the brain and spinal cord were studied in 57 Japanese patients with multiple sclerosis (MS). Twenty-three patients clinically displayed selective involvement of the optic nerve and spinal cord and were classified as having Asian-type MS. The other 34 patients had disseminated central nervous system involvement and were classified as having Western-type MS. Patients with Asian-type MS had fewer brain lesions shown by magnetic resonance imaging, but more gadolinium-enhanced spinal cord lesions than did patients with Western-type MS (47% vs 17%). Furthermore, the DR2-associated DRB1*1501 allele and DRB5*0101 allele were associated with Western-type MS (41.2%), but not with either Asian-type MS (0%) or healthy control subjects (14.2%). Heterogeneity in the immunogenetic background and in the magnetic resonance imaging features between the two subtypes of MS thus suggests the presence of two etiologically distinct diseases in Asians.

Alleles↗
PubMed1996

Central nervous system involvement in amyloid A type amyloidosis.

We report a 38-year-old male with recurrent cerebral infarction, who had a history of juvenile rheumatoid arthritis and suffered from ischemic necrosis of the jejunum at the age of 34 years. When the patient showed gastrointestinal symptoms, amyloid deposits were found with colon biopsy. The patient experienced recurrent episodes of headache and left homonymous lower quadrantanopsia at the age of 38 years. CT and MRI of the head revealed cerebral infarction in the right parieto-occipital region. At this time, amyloid deposits were detected in the mucosa of the stomach, duodenum, and rectum. Immunostaining revealed that amyloid fibrils were composed of amyloid A (AA) protein. It is possible that AA type amyloidosis may be of importance in the etiology of cerebral infarction in the young adult.

Adult↗
PubMed1996

The association of antibodies against human T cell lymphotropic virus type I (HTLV-I) pX gene mutant products with HTLV-I-associated myelopathy/tropical spastic paraparesis.

Antibodies specific for the products of the human T cell lymphotropic virus type I (HTLV-I) pX frame-shift mutants were studied by ELISA. The serum IgG antibodies to the synthetic peptide corresponding to one nucleotide insertion at position 7784 were significantly more common in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients than in HTLV-I carriers who had neither HAM/TSP nor adult T cell leukemia (39% vs. 5%). The seropositivities to the other synthetic peptides, which corresponded to the one nucleotide deletion at position 7475 and the internal deletion of nt 7754-7819 and nt 7853-7936, were rare. A genetic study confirmed the presence of the responsible mutation of the pX gene in peripheral blood mononuclear cells and central nervous system tissue from HTLV-I-infected subjects with and without HAM/TSP. These results suggest that HTLV-I pX frame-shift mutants are expressed in vivo in HTLV-I carriers; they also induce antibodies. especially in those with HAM/TSP.

Adult↗
PubMed1996

[A family of autosomal dominant facio-limb-girdle muscular dystrophy].

A family of autosomal dominant facio-limb-girdle muscular dystrophy was reported. The proband was a 28-year-old male. His father and sister suffered from a similar disease. All patients developed weakness of lower limbs and atrophy of thigh at second to fourth decades. All showed mild facial and neck flexor weakness as well as proximal dominant weakness and atrophy of four limbs. Limb muscle involvement was more severe in lower limbs than in upper limbs in all cases. Interestingly, all showed limitation of ankle dorsiflexion (tight heel cord), although distal muscles of lower limbs were not involved or only mildly involved clinically. On laboratory examination, serum CK increased slightly. Needle EMG revealed low amplitude, polyphasic MUP in limb muscles in all cases. Biopsied muscles taken from the proband showed non-specific myogenic changes. Rimmed vacuoles were not observed. Our cases were different from Bethlem myopathy, because the age of onset was late and joint contractures were mild in our cases, as compared with Bethlem myopathy. Clinical manifestations of our family showed a strong resemblance to the family reported by Girchlist et al, but similar cases were not reported in Japan.

Adult↗
PubMed1995

A peptide-based human T cell leukemia virus type I vaccine containing T and B cell epitopes that induces high titers of neutralizing antibodies.

We have recently identified the principal linear neutralizing B cell epitopes of human T cell leukemia virus type I (HTLV-I) on the envelope protein gp46, amino acids (aa) 187-199, by using a number of human mAbs. We therefore propose that this region would be a good candidate for a peptide-based HTLV-I vaccine. To develop a peptide-based vaccine that can induce a high titer of neutralizing Abs against HTLV-I, we first synthesized peptides of various lengths containing aa187-199. Because the addition of gp46 aa181-186 or aa200-210 to either the N-terminus or C-terminus of SP187-199 did not alter the antigenicity of the principal neutralizing determinant, we prepared two peptide-based vaccines, MAP181-203 and MAP181-210, by conjugating SP181-203 and SP181-210 with a branched polylysine oligomer. In rabbits, X4 to X8 and X8 to X64 titers of the neutralizing Abs were induced by immunization with MAP181-203 and MAP181-210, respectively. Furthermore, high titers of neutralizing Abs (X40 to X320) were elicited in five different strains of rats by immunization with MAP181-210. We also identified the major T cell epitope on gp46 aa194-210 in various strains of rats immunized with MAP181-210. Furthermore, the peripheral T lymphocytes obtained from the majority of HTLV-I-infected patients including HTLV-I-associated myelopathy/tropical spastic paraparesis, adult T cell leukemia/lymphoma, and healthy carriers, proliferated in response to the peptides containing aa194-210. These results indicated that MAP181-210 contains a T cell helper epitope on aa194-210 not only in rats and rabbits, but also in humans with various HLA haplotypes. It is therefore possible that MAP181-210 could become one of the candidates for a peptide-based HTLV-I vaccine for human use.

Amino Acid Sequence↗
PubMed1995

Characterization of cerebral white matter lesions of HTLV-I-associated myelopathy/tropical spastic paraparesis in comparison with multiple sclerosis and collagen-vasculitis: a semiquantitative MRI study.

The brain lesions were studied by magnetic resonance imaging (MRI) in 29 HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), 43 multiple sclerosis (MS) (11 with a primary progressive course: PPMS and 32 with a relapsing-remitting course: RRMS), 23 collagen-vasculitis and 54 HTLV-I-seronegative patients with other non-inflammatory neurological disorders (OND), according to the size of the lesions and their location in the brain (deep and subcortical white matter, periventricular white matter, infratentorial region and gray matter). Semiquantitative MRI analyses revealed the followings. (1) The frequency of either small or large lesions located in the periventricular as well as deep and subcortical white matter was significantly higher in HAM/TSP than in OND patients (p < 0.006, chi 2 test). In addition, the number of small lesions in the deep and subcortical, and periventricular white matter was significantly greater in HAM/TSP than in OND patients (p < 0.0003, Mann-Whitney U-test). (2) The HAM/TSP patients significantly exceeded the collagen-vasculitis patients in the frequency and the number of small lesions located in the periventricular region (p < 0.0001, chi 2 test, and p < 0.05, Mann-Whitney U-test, respectively), although no difference was found in case of those in the deep and subcortical white matter. (3) The HAM/TSP group had a lower frequency of small deep and subcortical white matter, small infratentorial and large periventricular lesions than the entire MS group (p < 0.05, chi 2 test). The PPMS group greatly exceeded the HAM/TSP group in the number of MRI lesions in all brain regions (p < 0.05, Mann-Whitney U-test), whereas RRMS and HAM/TSP patients showed a similar number of lesions (p > 0.1, Mann-Whitney U-test). Both the difference between HAM/TSP and collagen-vasculitis and the similarities between HAM/TSP and RRMS in the MRI features suggest that although all commonly have a vasculitic process as a necessary component, some other factor, probably with demyelinating effects, is operative HAM/TSP.

Adult↗
PubMed1995

Hepatitis C virus associated cryoglobulinemic neuropathy successfully treated with plasma exchange.

A 28-year-old Japanese woman who suffered from mononeuritis multiplex was admitted to our hospital. Serological study revealed cryoglobulinemia (type III), hypocomplementemia, high titers of rheumatoid factor (RF), and positive antihepatitis C virus (HCV) antibody. Nerve conduction velocities were slower in sensory nerves than in motor nerves. Biopsied sural nerve showed a marked decrease of myelinated fibers but no evidence of angitis. She received plasma exchange and cryoglobulinpheresis over a period of 2 months with approximately 2.0 L (40 ml/kg) of plasma replaced in each procedure. Both plasma exchange and cryoglobulinpheresis alleviated clinical symptoms, and nerve conduction velocities were improved in several nerves. The serum cryoglobulin level was markedly reduced after the treatment together with the recovery of the C4 level. Thus, complements appeared to be consumed in large quantities in the presence of cryoglobulinemia in this patient. Efficacy of cryoglobulinpheresis indicates the possibility that cryoglobulins produced in association with HCV infection played a role in damaging the nerve directly through the activation of the complement system.

Adult↗