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Biomedical subjects

S Tsuji

Publications and source records attributed to S Tsuji.

At least 379 records · Page 21Linked to original sources
PubMed1997

Abeta1-40 but not Abeta1-42 levels in cortex correlate with apolipoprotein E epsilon4 allele dosage in sporadic Alzheimer's disease.

Apolipoprotein E (ApoE) epsilon4 allele is established to be a risk factor for the development of late-onset Alzheimer's disease (AD) which is associated with increased frequency of senile plaques and extent of amyloid angiopathy. In a recent report, we demonstrated that ApoE epsilon4 dosage correlates with an increase in A beta1-40 but not A beta1-42/43-immunoreactive plaques. In the present study, we sought to confirm this relationship at a biochemical level by using a sensitive ELISA to measure the amounts of A beta1-42/43 and A beta1-40 in cerebral cortex in 36 cases of sporadic AD. We found that dosage of ApoE epsilon4 allele correlated significantly with cortical A beta1-40 levels, while levels of A beta1-42 showed no significant association with genotype. These results parallel our immunohistochemical findings and suggest that A beta1-40 may play a key role in the pathogenesis of late-onset sporadic AD.

Aged↗
PubMed1997

Gene locus for autosomal recessive distal myopathy with rimmed vacuoles maps to chromosome 9.

Distal myopathy with rimmed vacuoles is an autosomal recessive muscular disorder, characterized clinically by weakness of the distal muscles in the lower limbs in early adulthood. Recently, the gene locus for familial vacuolar myopathy with autosomal recessive inheritance (hereditary inclusion body myopathy) was mapped to chromosome 9 by genome-wide linkage analysis of nine Persian-Jewish families. Since both disease conditions share similar clinical, genetic, and histopathological features, we analyzed seven families with distal myopathy with rimmed vacuoles using ten microsatellite markers within the region of the hereditary inclusion body myopathy locus. Significantly high cumulative pairwise lod scores were obtained with three markers: D9S248 (Z(max) = 5.90 at theta = 0), D9S43 (Z(max) = 5.25 at theta = 0), and D9S50 (Z(max) = 4.23 at theta = 0). Detection of obligate recombination events as well as multipoint linkage analysis revealed that the most likely location of the distal myopathy with rimmed vacuoles gene is in a 23.3-cM interval defined by D9S319 and D9S276 on chromosome 9. The results raise the possibility that distal myopathy with rimmed vacuoles and hereditary inclusion body myopathy in Persian Jews are allelic diseases.

Adult↗
PubMed1997

Spinocerebellar ataxia type 6: CAG repeat expansion in alpha1A voltage-dependent calcium channel gene and clinical variations in Japanese population.

Autosomal dominant spinocerebellar ataxias (SCAs) are clinically and genetically a heterogeneous group of neurodegenerative disorders. Recently, mild CAG repeat expansion in the alpha1A voltage-dependent calcium channel gene has been found to be associated with a type of autosomal dominant SCA (SCA6). We analyzed 98 Japanese families with autosomal dominant SCAs, for whom CAG repeat expansions of the SCA1, SCA2, Machado-Joseph disease/SCA3, and dentatorubral-pallidoluysian atrophy genes were excluded, and 5 apparently sporadic cases of cortical cerebellar atrophy. The diagnosis of SCA6 was confirmed in 30 families (31%) comprising 47 affected individuals and 1 sporadic case. The size of expanded CAG repeats ranged from 21 to 26 repeat units and was found to be correlated inversely with age at onset. We identified 2 SCA6 patients homozygous for expanded CAG repeats, whose ages at onset were earlier than the 95% lower confidence level, suggesting the presence of a gene dosage effect of expanded CAG repeat. Ataxia is the most common initial symptom found in 45 of the 48 patients. Patients with a prolonged disease course showed other accompanying clinical features including dystonic postures, involuntary movements, and abnormalities in tendon reflexes.

Adult↗
PubMed1997

Discrepancy between blood flow and muscarinic receptor distribution in rat brain after middle cerebral artery occlusion.

To clarify whether muscarinic acetylcholine receptor (mAChR) binding can be a viable muscarinic neuronal marker which provides therapeutic information different from perfusional information in global brain, we evaluated the discrepancy between the distribution of cerebral blood flow (CBF), mAChR and its five subtypes of messenger ribonucleic acid (mRNA) in the acute (n=9) and chronic (n=8) phases of a middle cerebral artery (MCA) occlusion model and in sham-operated controls (n=6). In the acute phase, regional CBF was markedly reduced in the MCA territory, whereas mAChR was not reduced and the mRNA was reduced only slightly. In the chronic phase, mAChR was reduced markedly in the infarcted lesion and the mRNA was also reduced. The mAChR was slightly reduced in the ipsilateral substantia nigra and pontine nucleus because of remote effects; however, regional CBF in the substantia nigra was slightly increased and did not change in the pontine nucleus. The discrepancy between CBF and mAChR was clarified, and the tendency toward a reduction in mRNA in the acute ischaemic region without a reduction in mAChR suggested the presence of cholinergic neurons which were viable but hypometabolic. It is concluded that mAChR imaging may be of value for the assessment of the viable cholinergic neuron density in vivo.

Animals↗
PubMed1997

Thalamic form of Creutzfeldt-Jakob disease or fatal insomnia? Report of a sporadic case with normal prion protein genotype.

We describe a 68-year-old man with a 53-month history of progressive dementia and clinical features of a progressive supranuclear palsy-like syndrome and dysautonomia. In the late stage of his illness, the patient also developed generalized myoclonic seizures. There was no family history of similar disorders. Histological examination revealed neuronal loss and gliosis with spongiosis in the cerebral cortex. In addition, more severe neuronal loss and gliosis without spongiosis were observed in the thalamus, especially in the anterior ventral and mediodorsal nuclei, and the inferior olivary nucleus. There was also obvious loss of Purkinje cells. Immunohistochemically, no protease-resistant prion protein (PrPres)-positive structures were demonstrated. However, Western blotting revealed the presence of PrPres in the cerebral cortex. This patient had a wild type of PrP genotype. We initially considered this to be a case of the thalamic form of Creutzfeldt-Jakob disease (CJD) with a long duration. However, it is noteworthy that essentially similar pathology, albeit with less severe cerebral cortical changes, has also been reported in fatal familial insomnia, a newly identified phenotypically different prion disease with a mutation in the PrP gene. On the basis of clinicopathological features, we eventually felt that this patient was more likely to have been a sporadic case of fatal insomnia (FI) of long duration. The present case appears to draw further attention to the possible relationship between CJD and FI.

Aged↗
PubMed1997

Molecular genetic evidence of clinical heterogeneity in Fukuyama-type congenital muscular dystrophy.

Fukuyama-type congenital muscular dystrophy (FCMD) is an autosomal recessive severe muscular dystrophy associated with brain malformation. The gene responsible for FCMD was mapped to chromosome 9q31, a region in which convincing evidence of strong linkage disequilibrium between FCMD and mfd220 (D9S306) was recently found. FCMD is also characterized clinically by a peak motor function which, at best, allows patients to sit unassisted or slide on the buttocks. However, a small fraction of patients acquire the capacity to walk unassisted. Whether such ambulant cases belong to the FCMD spectrum or to a different disease entity has been a topic of considerable debate. We performed linkage analysis for ten families with ambulant cases using DNA markers flanking the FCMD locus. The mfd220 locus yielded a significant lod score of 3.09 for ambulant FCMD. We also found evidence for linkage disequilibrium between ambulant FCMD and mfd220. We further conducted haplotype analysis in FCMD siblings with different phenotypes, one of whom was ambulant while the other was not. The results indicate that the FCMD siblings share exactly the same haplotype at nine marker loci spanning 23.3 cM surrounding the FCMD locus. On the basis of these results, we conclude that, genetically, ambulant cases are, in fact, part of the FCMD spectrum.

Adolescent↗
PubMed1997

Adult onset globoid cell leukodystrophy (Krabbe disease): analysis of galactosylceramidase cDNA from four Japanese patients.

We examined galactosylceramidase (GALC) cDNA in four Japanese patients with adult onset globoid cell leukodystrophy (Krabbe disease; AO-GLD) by polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) analysis, subsequent sequence determination, and restriction enzyme digestion of PCR products, initial symptoms were the onset of slowly progressive spastic paraplegia from the middle of the second decade, and all patients had diminished GALC activity in their leukocytes. We identified three missense mutations (I66M, G270D, L618S) and one exon-6 skipping (535-573del). Two of the patients had only the I66M mutant mRNA, and one only the G27OD mutant mRNA. The fourth patient carried a compound heterozygous mutation of 535-573del and L618S. To determine the enzymatic activities produced by these mutations, we constructed mutated GALC cDNAs and expressed them in COS-1 cells. Three mutations, viz., G270D, L618S, and exon-6 skipping (535-573del), produced diminished GALC activity as expected. The I66M mutation in the wild-type GALC cDNA(I289) had normal activity, but when this mutation and the V289 polymorphism were introduced into the same allele, it had decreased activity. Thus, the combination of a unique mutation and polymorphism causes conformational change in the GALC enzyme, resulting in low enzymatic activity. AO-GLD mutations, including those found here, are located in the N-terminus (I66M, G270D, 535-573del) or C-terminus (L618S) of the GALC enzyme, whereas the reported mutations in the infantile form (IF-GLD) are in the central domain. This difference in mutation sites may affect the clinical features of GLD.

Adult↗
PubMed1997

Confirmation of a second locus for CMT2 and evidence for additional genetic heterogeneity.

The Charcot-Marie-Tooth (CMT) neuropathies are a group of disorders exhibiting neurophysical, pathological and genetic heterogeneity. CMT2 is a diagnostic subtype of this group of disorders characterized by variable expression and age-of-onset and normal or slightly diminished nerve conduction velocities. Previously, linkage and heterogeneity had been reported in CMT2 with linked families localizing to chromosome 1p (CMT2A). Recently a second CMT2 locus has been described on chromosome 7 in a single large CMT2 family (CMT2D). We have performed pedigree linkage analysis on 15 CMT2 families (N = 371 individuals, 106 affected family members) and have confirmed linkage to chromosome 7. Furthermore, using both admixture and multipoint linkage analysis we show conclusive evidence for additional heterogeneity within this clinical subtype with evidence of families that exclude linkage to both the CMT2D and CMT2A regions. In addition, unlike the previous report we found no obvious consistent clinical differences between the linked family types.

Charcot-Marie-Tooth Disease↗
PubMed1997

A missense mutation in the SOD1 gene in patients with amyotrophic lateral sclerosis from the Kii Peninsula and its vicinity, Japan.

Unusually high incidences of amyotrophic lateral sclerosis (ALS) have been observed in the natives of the Kii Peninsula of Japan as well as the indigenous Chamorro people of Guam. Given the relatively high incidence of familial onset of the disease in the Kii Peninsula, we performed mutational analyses of the SOD1 gene of 23 patients (three familial cases and 20 sporadic cases) with ALS from the Kii Peninsula and its vicinity. In two of the 23 patients, we identified the same missense mutation (substitution of Thr for Ile 113) in exon 4 as a heterozygous state. The Ile 113Thr mutation in the SOD1 gene has been identified in some familial as well as sporadic cases with ALS, as a mutation with a low penetrance. This mutation has been reported to be associated with the formation of neurofibrillary tangles in an English family, which is a characteristic feature of ALS in the Kii Peninsula. These results suggest that the Ile113Thr mutation is a characteristic and relatively prevalent mutation in this area.

Adult↗
PubMed1997

Machado-Joseph disease gene products carrying different carboxyl termini.

Three cDNA clones for the Machado-Joseph disease gene (MJD1) were isolated, two of which have a new exon sequence and a distinct 3' terminal nucleotide sequence resulting in a new carboxyl terminal domain in the translated product. The nucleotide sequence of the other one is similar to the previously published one except for five polymorphisms, one of which is a single nucleotide substitution resulting in a change from the stop codon (TAA; allele A) to a tyrosine residue (TAC; allele C). Genetic analysis results suggest that Japanese MJD mutations are associated with allele A.

Amino Acid Sequence↗
PubMed1997

Plasma and gastric mucosal endothelin-1 concentrations in patients with peptic ulcer.

Peptic ulcer in the human stomach causes localized destruction of the gastric wall, which may be associated with focal vascular insufficiency. Endothelin-1, an extremely potent vasoconstrictor peptide, modulates regional blood flow in the vasculature of stomach, suggesting a role for endothelin-1 in peptic ulcer. We examined the relationship among endogenous plasma and mucosal endothelin-1 concentrations and the severity and area of ulcer in 19 patients with gastric ulcers and eight healthy adults. Endothelin-1 concentrations were measured by enzyme immunoassay in plasma and gastric mucosal specimens from ulcer margins, corpus, and antrum. The severity and area of ulcer were assessed endoscopically. Plasma endothelin-1 concentrations in active (P < 0.01 compared with normal) and healing (P < 0.05) stages of ulcer were significantly greater than those in normal subjects. Plasma endothelin-1 concentrations, but not mucosal endothelin-1 concentrations in the ulcer margin, were significantly associated with the severity of the ulcer. There was a significant positive correlation between plasma endothelin-1 concentrations and area of ulcer (r = 0.70, P < 0.01). In conclusion, locally increased endothelin-1 may be an important mediator contributing to the pathogenesis of peptic ulcer.

Adult↗
PubMed1997

Polysialic acid synthase (ST8Sia II/STX) mRNA expression in the developing mouse central nervous system.

A comparative study was undertaken to correlate the immunohistochemical localization of polysialic acid (PSA) and the in situ localization of ST8Sia II mRNA. In situ hybridization of postnatal day 3 mouse brain showed high levels of ST8Sia II mRNA expression in the cerebral neocortex, striatum, hippocampus, subiculum, medial habenular nucleus, thalamus, pontine nuclei, and inferior colliculus; intermediate-level expression in the olfactory bulb, hypothalamus, superior colliculus, and cerebellum; and low-level expression in other regions. The distribution of ST8Sia II mRNA in the neocortex and cerebellum coincided with the immunohistochemical localization of PSA. During brain development, ST8Sia II mRNA started decreasing and had almost disappeared by postnatal day 14. Comparison between ST8Sia II and IV mRNA expression was also undertaken by northern blot analysis and competitive PCR analysis. During the late embryonic to early postnatal stages of the mouse CNS, the ST8Sia II mRNA showed abundant mRNA expression compared with the ST8Sia IV mRNA. Competitive PCR analysis of the adult mouse CNS showed weak expression of the two genes in the olfactory bulb, thalamus, hippocampus, and eyes. The regional and transient expression of ST8Sia II mRNA coincides with that of PSA, suggesting that ST8Sia II is closely involved in the biosynthesis and expression of PSA in the developing mouse CNS.

Aging↗
PubMed1997

Japanese families with autosomal dominant pure cerebellar ataxia map to chromosome 19p13.1-p13.2 and are strongly associated with mild CAG expansions in the spinocerebellar ataxia type 6 gene in chromosome 19p13.1.

Autosomal dominant cerebellar ataxia is a group of clinically and genetically heterogeneous disorders. We carried out genomewide linkage analysis in 15 families with autosomal dominant pure cerebellar ataxia (ADPCA). Evidence for linkage to chromosome 19p markers was found in nine families, and combined multipoint analysis refined the candidate region to a 13.3-cM interval in 19p13.1-p13.2. The remaining six families were excluded for this region. Analysis of CAG-repeat expansion in the alpha1A-voltage-dependent calcium channel (CACNL1A4) gene lying in 19p13.1, recently identified among 8 small American kindreds with ADPCA (spinocerebellar ataxia type 6 [SCA6]), revealed that 8 of the 15 families studied had similar, very small expansion in this gene: all affected individuals had larger alleles (range of CAG repeats 21-25), compared with alleles observed in neurologically normal Japanese (range 5-20 repeats). Inverse correlation between the CAG-repeat number and the age at onset was found in affected individuals with expansion. The number of CAG repeats in expanded chromosomes was completely stable within each family, which was consistent with the fact that anticipation was not statistically proved in the SCA6 families that we studied. We conclude that more than half of Japanese cases of ADPCA map to 19p13.1-p13.2 and are strongly associated with the mild CAG expansion in the SCA6/CACNL1A4 gene.

Adult↗
PubMed1997

Mouse beta-galactoside alpha 2,3-sialyltransferases: comparison of in vitro substrate specificities and tissue specific expression.

Four types of beta-galactoside alpha 2,3-sialyltransferase (ST3Gal I-IV) have been cloned from several animals, but some contradictory observations regarding their substrate specificities and expression have been reported. Therefore, it is necessary to concurrently analyze the substrate specificities of the four enzymes, of which the source should be one animal. Accordingly, the acceptor substrate specificities and gene expression of mST3Gal I-IV were analyzed. Since we had already cloned ST3Gal I and II, as previously reported (Lee, Y.-C. et al., Eur. J. Biochem., 216, 377-385 (1993); J. Biol. Chem., 269, 10028-10033 (1994)), the cDNAs of ST3Gal III and IV were cloned from mouse cDNA libraries. Each of the four enzymes was expressed in COS-7 cells as a recombinant enzyme fused with protein A, and applied on an IgG-Sepharose gel to eliminate endogenous sialyltransferase activity. ST3Gal I and II showed the highest activity toward Gal beta 1, 3 GalNAc (type III), very low activity toward Gal beta 1,3GlcNAc (type I), but none toward Gal beta 1,4GlcNAc (type II). ST3Gal III and IV exhibited high activity toward the type I and II disaccharides, but very low activity toward the type III one. On the other hand, asialo-GM1 (Gg4Cer) was as good a substrate for ST3Gal I and II as the type III disaccharide, though ST3Gal III and IV hardly utilized glycolipids as substrates, as indicated by in vitro experiments. Northern blot analysis revealed that enzymes of the ST3Gal-family are expressed mainly in a tissue-specific manner. The ST3Gal I gene was strongly expressed in spleen and salivary gland, and weakly in brain, liver, heart, kidney, and thymus. The ST3Gal II gene was strongly expressed in brain, and weakly in colon, thymus, salivary gland, and testis, and developmentally expressed in liver, heart, kidney, and spleen. The ST3Gal III and IV genes were expressed in a wide variety of tissues. These differences in tissue specific expression suggest the expression of each ST3Gal influences the distribution of sialyl-glycoconjugates in vivo.

Amino Acid Sequence↗
PubMed1997

Regulated expression system for GD3 synthase cDNA and induction of differentiation in Neuro2a cells.

It was reported recently by our group that the transfection of GD3 synthase cDNA into Neuro2a cells, a neuroblastoma cell line, caused cell differentiation with neurite sprouting (Kojima et al., 1994; J. Biol. Chem., 269, 30451-30456). To further explore this phenomenon in detail, we applied tetracycline-regulated system to control the expression of GD3 synthase cDNA in Neuro2a cells. Under this system, the process of Neuro2a cell differentiation was rather slow, about 3 weeks of cell culturing in the absence of tetracycline was required for most cells to extend the neurite-like structures. The RNase protection assay indicated that the mRNA of GD3 synthase gene was first detected between 4 h and 8 h after the gene was activated and kept at approximately the same level through the process. Furthermore, time-course analysis of total ganglioside expressions has shown that GD3 and GT1b gangliosides appeared on the cell surface early in the process and reached the maximum level around day 6. We also found that the amounts of GD3 and GT1b on the cell surface started to decrease after day 6 and returned gradually to the basal values after 3 weeks. On the other hand, GQ1b and GD1b were started to be synthesized at early stage and the amounts were continuously to increase through the whole Neuro2a morphological change process. In addition, time-course analysis by flow cytometry method for GD3 and GQ1b suggested that the conversions of simple gangliosides to more complex gangliosides may be required to induce the Neuro2a differentiation. Our results indicated that the combination of cDNA transfection and regulated gene expression is a powerful tool to study the function of glycolipids and should have a general application to the glycobiology field.

Animals↗
PubMed1997

Single sperm analysis of the CAG repeats in the gene for Machado-Joseph disease (MJD1): evidence for non-Mendelian transmission of the MJD1 gene and for the effect of the intragenic CGG/GGG polymorphism on the intergenerational instability.

To investigate the mechanism of the meiotic instability of expanded CAG repeats in the gene for Machado-Joseph disease (MJD1), we analyzed the CAG repeat sizes of 1036 single sperm from six individuals with Machado-Joseph disease (MJD). The segregation ratio between single sperm with an expanded allele and those with a normal allele is significantly different (P <0.0001) from the expected 1:1 segregation ratio, which demonstrates segregation distortion of expanded alleles in male meiosis. In single sperm from individuals with the [expanded (CAG)n-CGG]/[normal (CAG)n-GGG] genotype, significantly greater instability of the CAG repeat was observed compared with single sperm from individuals with the [expanded (CAG)n-CGG]/[normal (CAG)n-CGG] genotype (F-test, P <0.001). These findings in single sperm confirm non-Mendelian transmission of the MJD1 gene and the effect of the intragenic CGG/GGG polymorphism on the intergenerational instability of the CAG repeats in the MJD1 gene, which have been observed in clinical and genetic studies. Our results indicate similarities and dissimilarities between MJD and Huntington's disease or myotonic dystrophy in terms of the inter-allelic interaction, segregation distortions and size distribution of trinucleotide repeats in mutant alleles. Further study is required to determine whether there is a common mechanism underlying the instability of the triplet repeats in 'triplet repeat diseases'.

Alleles↗
PubMed1997

Two polysialic acid synthases, mouse ST8Sia II and IV, synthesize different degrees of polysialic acids on different substrate glycoproteins in mouse neuroblastoma Neuro2a cells.

We previously cloned cDNAs encoding two different polysialic acid (PSA) synthases, ST8Sia II and IV, from mouse, and showed that both mouse ST8Sia II and IV can synthesize PSA on the neural cell adhesion molecule (NCAM) as well as other glycoproteins such as fetuin, at least in vitro (Kojima, N., Tachida, Y., Yoshida, Y., and Tsuji, S. (1996) J. Biol. Chem. 271, 19457-19463]. In the present study, to clarify how the two PSA synthases act differently in vivo, we first cloned PSA-expressing cell lines (N2a-II and N2a-IV) by stable transfection of the cDNA encoding either mST8Sia II or IV into mouse neuroblastoma Neuro2a cells, which do not express PSA but express NCAM, then compared the expression of the PSA and NCAM isoforms and de novo synthesis of PSA between N2a-II and N2a-IV. Western blotting with an anti-NCAM polyclonal antibody showed that NCAM was expressed as the polysialylated form in both ST8Sia II cDNA-transfected and ST8Sia IV cDNA-transfected Neuro2a cells, but that the polysialylated NCAMs expressed in ST8Sia IV cDNA-transfected clones migrated much slower on SDS-PAGE than those expressed in ST8Sia II cDNA-transfected clones. The slower migration of polysialylated NCAM of the ST8Sia IV cDNA-transfected clone (N2a-IV) than that of the ST8Sia II cDNA-transfected clone (N2a-II) was also observed when cells were metabolically labeled with [3H]glucosamine or pulse-chase labeled with [35S] methionine followed by immunoprecipitation with anti-PSA antibody or anti-NCAM monoclonal antibody. In addition, polysialylated N-glycans of PSA-carrying glycoproteins prepared from [3H] glucosamine-labeled N2a-IV by immunoprecipitation with anti-PSA monoclonal antibody were eluted at a much higher salt concentration than those from [3H] glucosamine-labeled N2a-II on an anion-exchange column. These results indicated that the degree of de novo polysialylation of NCAM by mST8Sia IV was much higher than that by mST8Sia II. In N2a-IV, NCAM-120, -140, and -180 were expressed as polysialylated forms, while polysialylation was restricted to NCAM-140 and -180, i.e., not NCAM-120, in N2a-ST8Sia II. Metabolic labeling of the cells with [3H] glucosamine, pulse-chase labeling with [35S] methionine followed by immunoprecipitation with anti-PSA antibody, and subsequent sialidase treatment revealed that NCAM-140 and -180 were specifically polysialylated in N2a-II, whereas not only NCAM but also other glycoproteins were de novo polysialylated in N2a-IV. The above results demonstrated that the two different PSA synthases, mST8Sia II and IV, synthesize PSA of different lengths on different substrate glycoproteins in vivo when the enzymes are expressed in neuroblastoma Neuro2a cells. These differences suggest that mST8Sia II and IV play different roles in the biosynthesis and expression of PSA.

Animals↗