Biomedical subjects

T Toda

Publications and source records attributed to T Toda.

At least 55 records · Page 3Linked to original sources

PubMed2000

Haplotype-phenotype correlation in Fukuyama congenital muscular dystrophy.

In typical Fukuyama congenital muscular dystrophy (FCMD), peak motor function is usually only unassisted sitting or sliding on the buttocks, though a few patients are able to walk at some point. However, a few patients have a severe phenotype and never acquire head control. In addition, it is clinically difficult to differentiate this severe FCMD from Walker-Warburg syndrome (WWS) or from muscle-eye-brain disease (MEBD). In order to establish a genotype-phenotype correlation, we performed haplotype analysis using microsatellite markers closest to the FCMD gene (FCMD) in 56 Japanese FCMD families, including 35 families whose children were diagnosed as FCMD with the typical phenotype, 12 families with a mild phenotype, and 9 families with a severe phenotype. Of the 12 propositi with the mild phenotype, 8 could walk and the other 4 could stand with support; 10 cases were homozygous for the ancestral founder (A-F) haplotype whereas the other 2 were heterozygous for the haplotype. In the 9 severe cases, who had never acquired head control or the ability to sit without support, 3 had progressive hydrocephalus, 2 required a shunt operation, and 7 had ophthalmological abnormalities. Haplotype analysis showed that 8 of the 9 cases of the severe phenotype are heterozygous for the A-F haplotype, and the other one homozygous for the haplotype. We confirmed that at least one chromosome in each of the 56 FCMD patients has the A-F haplotype. The rate of heterozygosity for the A-F haplotypes was significantly higher in severe cases than in typical or mild cases (P < 0.005). Severe FCMD patients appeared to be compound heterozygotes for the founder mutation and another mutation. Thus, the present study yielded molecular genetic evidence of a broad clinical spectrum in FCMD.

Brain↗

PubMed2000

A conserved small GTP-binding protein Alp41 is essential for the cofactor-dependent biogenesis of microtubules in fission yeast.

The proper folding of tubulins and their incorporation into microtubules consist of a series of reactions, in which evolutionarily conserved proteins, cofactors A to E, play a vital role. We have cloned a fission yeast gene (alp41(+)) which encodes a highly conserved small GTP-binding protein homologous to budding yeast CIN4 and human ARF-like Arl2. alp41(+) is essential, disruption of which results in microtubule dysfunction and growth polarity defects. Genetic analysis indicates that Alp41 plays a crucial role in the cofactor-dependent pathway, in which it functions upstream of the cofactor D homologue Alp1(D) and possibly in concert with Alp21(E).

Cell Division↗

PubMed2000

The IVS4 + 4 A to T mutation of the fanconi anemia gene FANCC is not associated with a severe phenotype in Japanese patients.

Fanconi anemia (FA) is an autosomal recessive disease characterized by congenital anomalies, aplastic anemia, and a susceptibility to leukemia. There are at least 8 complementation groups (A through H). Extensive analyses of the FA group C gene FANCC in Western countries revealed that 10% to 15% of FA patients have mutations of this gene. The most common mutation is IVS4 + 4 A to T (IVS4), a splice mutation in intron 4, which has been found only in patients of Ashkenazi Jewish ancestry. When we screened 29 Japanese patients (20 unrelated patients and 4 families) using polymerase chain reaction-single strand conformation polymorphism, we found 8 unrelated patients homozygous for IVS4. This is apparently the first non-Ashkenazi-Jewish population for whom this mutation has been detected. The Ashkenazi Jewish patients homozygous for IVS4 have a severe phenotype, in comparison with other FA patients. Our analyses of Japanese patients indicate no significant difference between IVS4 homozygotes and other patients with regard to severity of a clinical phenotype. Thus, ethnic background may have a significant effect on a clinical phenotype in FA patients carrying the same mutation. (Blood. 2000;95:1493-1498)

Adolescent↗

PubMed2000

The major low molecular weight apolipoprotein from normal and hyperlipidemia atherosclerosis-prone (LAP) Japanese quail.

The low molecular weight (LMW) apolipoprotein of apo C plays an important role in the metabolism of triglyceride-rich lipoproteins. This study aimed at a characterization of the major LMW apolipoproteins from normal quail strain, and also from LAP (hyperlipidemia atherosclerosis-prone) strain to identify its genetic disorder. The major LMW apoprotein cDNA clone from normal quail comprised of approximately 500 bp, and encoded polypeptide of 78 amino acid residues containing 57 amino acids as a mature apolipoprotein. Although the quail LMW apoprotein showed a low homology to either apo C-I, C-II, or C-III of other animals, it retained a well-developed amphipathic alpha-helix structure. There was no difference in the deduced primary structure of the quail LMW apoprotein between LAP and normal strain. An analysis of the mRNA expression showed that the quail LMW apoprotein was only expressed in the liver of both LAP and normal Japanese quail. No difference was noted in the hepatic expression of the quail LMW apoprotein mRNA between normal and LAP strains with neither normal nor atherogenic dietary conditions. The structure and expression of the major LMW apoprotein thus had no relevance to higher susceptibility of LAP strain to the experimental atherosclerosis.

Amino Acid Sequence↗

PubMed2000

Proteomic analysis of Epstein-Barr virus-transformed human B-lymphoblastoid cell lines before and after immortalization.

Infection of human B lymphocytes with Epstein-Barr virus (EBV) induces proliferative B-lymphoblastoid cell lines (LCLs). However, the majority of EBV-transformed LCLs are mortal and unable to avoid cellular senescence. In our previous experiment, three immortalized LCLs were established by passages of EBV-transformed LCLs for nearly five years accompanied by strong telomerase activity. In the present study, proteomic profiles of these three LCLs were analyzed comparatively at the early and the late passages of cell culture, and a protein spot was found which most significantly decreased with the immortalization in two LCLs. The expression of the protein in the third LCL was suppressed at 17 population doubling level (PDL), already suggesting that part of the immortalization process had been initiated before 17 PDL. The protein was assigned to ssp7001 (16.3 kDa, pI 6.0) by referring to our TMIG-2DPAGE proteome database. The protein was transferred onto a polyvinylidene difluoride (PVDF) membrane and digested with lysilendopeptidase to perform peptide mass fingerprinting by nanoelectrospray ionization mass spectrometry (nano-ESI-MS). Subsequent MS-Fit database search indicated that ssp7001 is a phosphoprotein stathmin. This speculation was confirmed by the tandem MS (MS/MS) analysis in a Q-Tof system and by Edman degradation microsequencing.

Amino Acid Sequence↗

PubMed2000

Proteome analysis of mouse brain: two-dimensional electrophoresis profiles of tissue proteins during the course of aging.

Mouse brain proteins were isolated from five regions (cerebellum, cerebral cortex, hippocampus, striatum, and cervical spinal cord) at five ages from the 10th week to the 24th month, and separated by two-dimensional gel electrophoresis (2-DE). 2-DE was carried out with an immobilized pH gradient bar in the first dimension, and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the second dimension. Over one thousand protein spots were visualized by silver staining and quantified by image processing. In the analyses, 58 protein spots were distinguishable among the above five brain regions, and 17 proteins were shown to be varied in quantity in the course of aging. Partial amino-terminal sequences and/or internal sequences for a total of 301 protein spots were analyzed. One hundred and eighty proteins appeared to have blocked N-termini and 122 proteins were identified. Twenty-seven new proteins were identified by sequence homology search. A mouse brain proteome database was constructed, which consists of the 2-DE map images and the respective spot data files with 15 related references.

Acrylic Resins↗

PubMed2000

Reconstruction of alveolar bone defect by calcium phosphate compounds.

Osteoconductivity of newly developed calcium phosphate cements (CP-1, CP-2) was estimated in mandibular periapical alveolar bone of rats. The powder phase of CP-1 was an equimolar mixture of tetracalcium phosphate and dicalcium phosphate dihydrate, and that of CP-2 was alpha-tricalcium phosphate. The liquid phase of CP-1 and CP-2 was a solution containing tannic acid and citric acid. CP-1, CP-2, an apatitic sealer (ARS), or a zinc oxide eugenol sealer (ZOE) was respectively applied in the mechanically injured periapical regions through the root canals of both mandibular first molars of 15 rats. A further 15 rats were used as controls with no material in the region. The results of histopathological examination at 1, 3, and 5 weeks after operation were analyzed by the chi(2) test (95% confidence level). At 1 week, foreign-body giant cells were observed around CP-1 and CP-2, but not around ARS or ZOE. Congestion of small blood vessels was seen in bone defect areas of the controls. After 5 weeks, statistically significant bone reconstruction was induced by application of CP-1 (80.0%), CP-2 (90.0%) compared with ARS (33.3%). Fibrous scaring was seen in the controls. It is concluded that resolvability of CP-1 and CP-2 should contribute to osseous healing.

Animals↗

PubMed2000

Bilateral receptive field neurons in the hindlimb region of the postcentral somatosensory cortex in awake macaque monkeys.

Single-neuron activities were recorded in the hindlimb region of the primary somatosensory cortex and part of area 5 in awake Japanese monkeys. A total of 1050 units were isolated from five hemispheres of four animals. Receptive fields (RFs) and submodalities were identified for 90% of isolated neurons in areas 3a and 3b. The percentage decreased as the recoding site moved to the more caudal areas. Deep or skin submodality neurons were dominant in area 3a or area 3b, respectively. Deep submodality neurons increased in more caudal areas and were the majority in areas 2 and 5. These observations were consistent with those in the hand and/or digit or arm and/or trunk region. The identified neurons were classified by their RF positions into four types: the foot, leg, foot and leg, or hindlimb and other body parts type. Among 831 identified neurons, 33 neurons had bilateral RFs, 14 had ipsilateral RFs, and the rest (N=784) had contralateral RFs. The relative incidence of neurons with bilateral or ipsilateral RFs among identified neurons was less than 1% in areas 3a, 3b, and 1, and 16% or 25% in areas 2 or 5, respectively. Within areas 2 and 5, the percentage of neurons with bilateral or ipsilateral RFs was significantly smaller in the foot type (5%) than in other RF types (24-57%). RFs of the foot type were on the sole or single toe but never on multiple toes. These observations contrasted with the previous findings that neurons with bilateral RFs were more frequently seen in the hand and/or digit region and that RFs on multiple digit tips were dominant there. The present study thus demonstrated that neurons with bilateral RFs do exist in the hindlimb region. Similarly to the forelimb region, they were found mostly in areas 2 and 5, the caudalmost areas of the postcentral gyrus and hierarchically higher stages in information processing. The relative paucity of neurons with bilateral RFs on the foot, especially those with RFs on multiple toes, may reflect functional differences between the foot and the hand.

Action Potentials↗

PubMed2000

Characterisation of fission yeast alp11 mutants defines three functional domains within tubulin-folding cofactor B.

The proper folding of tubulins prior to their incorporation into microtubules requires a group of conserved proteins called cofactors A to E. In fission yeast, homologues of these cofactors (at least B, D and E) are necessary for the biogenesis of microtubules and for cell viability. Here we show that the temperature-sensitive alp11-924 mutant, which is defective in the cofactor B homologue, contains an opal nonsense mutation, which results in the production of a truncated Alp11B protein (Alp11(1-118). We isolated a tRNA(Trp) gene as a multicopy suppressor of this mutation, which rescues alp11-924 by read-through of the nonsense codon. The truncated Alp1-118 protein lacks the C-terminal half of Alp11B, consisting of a central coiled-coil region and the distal CLIP-170 domain found in a number of proteins involved in microtubule functions. Both of these domains are required for the maintenance of microtubule architecture in vivo. Detailed functional analyses lead us to propose that Alp11B comprises three functional domains: the N-terminal half executes the essential function, the central coiled-coil region is necessary for satisfactory maintenance of cellular alpha-tubulin levels, and the C-terminal CLIP-170 domain is required for efficient binding to alpha-tubulin.

Amino Acid Sequence↗

PubMed2000

Age and origin of the FCMD 3'-untranslated-region retrotransposal insertion mutation causing Fukuyama-type congenital muscular dystrophy in the Japanese population.

Fukuyama-type congenital muscular dystrophy (FCMD), an autosomal recessive disorder with a high prevalence in the Japanese population, is characterised by severe muscular dystrophy associated with brain malformation (cortical dysgenesis) and mental retardation. In Japan, 87% of FCMD-bearing chromosomes carry a 3-kb retrotransposal insertion of tandemly repeated sequences within the disease gene recently identified on chromosome 9q31, and most of them share a common founder haplotype. FCMD is the first human disease known to be caused primarily by an ancient retrotransposal integration. By applying two methods for the study of linkage disequilibrium between flanking polymorphic markers and the disease locus, and of its decay over time, the age of the insertion mutation causing FCMD in Japanese patients is calculated to be approximately 102 generations (95% confidence interval: 86-117 g), or slightly less. The estimated age dates the most recent common ancestor of the mutation-bearing chromosomes back to the time (or a few centuries before) the Yayoi people started migrating to Japan from the Korean peninsula. This finding makes the molecular population genetics of FCMD understandable in the context of Japan's history and the founder effect consistent with the prevalent theory on the origins of the modern Japanese population.

Asian People↗

PubMed2000

A patient with primary biliary cirrhosis associated with autoimmune hemolytic anemia.

Primary biliary cirrhosis is often associated with autoimmune conditions, such as thyroid disease, sicca complex, and rheumatoid arthritis. However, an association with autoimmune hemolytic anemia has rarely been reported. We present a case of primary biliary cirrhosis associated with warm type autoimmune hemolytic anemia, and we review prior reports.

Aged↗

PubMed2000

A case of Walker-Warburg syndrome.

Walker-Warburg syndrome (WWS) is an autosomal recessive disorder characterized by type II lissencephaly, cerebellar and retinal anomalies, and congenital muscular dystrophy. We report a female diagnosed with WWS based on clinical criteria. This patient was found to have fetal hydrocephalus on ultrasonography at 29 weeks of gestation, and exhibited severe hypotonia, ocular malformations, and hydrocephalus at birth. MRI revealed type II lissencephaly, hydrocephalus, and other severe brain malformations. Genetic analysis was performed to distinguish WWS from severe Fukuyama-type congenital muscular dystrophy (FCMD), which has numerous findings in common. This revealed no expression of the founder haplotype or single-stranded conformation polymorphism (SSCP) abnormalities. Since the life expectancy of patients with FCMD is longer, differential diagnosis should be performed precisely.

Abnormalities, Multiple↗

PubMed2000

Current status and perspectives of proteomics in aging research.

The accumulation of non-enzymatic modifications on both DNA and protein molecules under the attack of reactive oxygen species (ROS), is one of the most possible factors responsible for the functional deterioration in aged cells. Direct protein modifications as well as DNA damages may be detectable, in part, by proteome analysis if the gene expression is affected by the damages on DNA. The novel term "proteome", which is a compound of "protein" and "genome", means a whole set of proteins expressed in a tissue or a cell strain to be investigated. Proteomics is a methodology for analyzing proteomes. In proteomics, two-dimensional gel electrophoresis is performed primarily to separate constitutive proteins, followed by mass spectrometry to identify each protein of interest and to determine a possible post-translational modification. Proteomics has offered us an innovative tool for investigating the molecular mechanisms of cellular aging.

Aging↗

PubMed2000

Congenital muscular dystrophy associated with calf hypertrophy, microcephaly and severe mental retardation in three Italian families: evidence for a novel CMD syndrome.

We describe four Italian patients (aged 3, 4, 12, and 13 years ) affected by a novel autosomal form of recessive congenital muscular dystrophy. These patients were from three non-consanguineous families and presented an almost identical phenotype. This was characterized by hypotonia at birth, joint contractures associated with severe psychomotor retardation, absent speech, inability to walk and almost no interest in their surroundings. In addition, all patients had a striking enlargement of the calf and quadriceps muscles. Ophthalmologic examination revealed no structural ocular abnormalities in any of the children; one patient had severe myopia. In all cases a magnetic resonance imaging of the brain showed an abnormal posterior cranial fossa with enlargement of the cisterna magna and variable hypoplasia of the vermis of the cerebellum. Abnormality of the white matter was also present in all patients, in the form of patchy signal most evident in the periventricular areas. Serum CK was grossly elevated in all. The muscle biopsy from all cases showed dystrophic changes compatible with congenital muscular dystrophy. Immunofluorescence studies showed mild to moderate partial deficiency of laminin alpha 2 chain. Linkage analysis in the only informative family excluded the known loci for congenital muscular dystrophy, including laminin alpha 2 chain on chromosome 6q2, the Fukuyama congenital muscular dystrophy locus on 9q3 and the muscle-eye-brain disease on chromosome 1p3. We propose that this represent a novel severe variant of congenital muscular dystrophy, with associated central nervous system involvement.

Adolescent↗

PubMed2000

Genetic heterogeneity in three Chinese children with Fukuyama congenital muscular dystrophy.

Three Chinese patients, two boys and one girl, were afflicted with the typical clinical, myopathological and neuroradiological findings of Fukuyama congenital muscular dystrophy (FCMD). Polymorphism analysis of our patients did not reveal the founder haplotype (138-192-147-183 in D9S2105-D9S2170-D9S2171-D9S2107) of Japanese FCMD, even though one patient was descended from Japanese ancestry. Full mutational analysis of the fukutin gene revealed that there is neither 3 kb insertion nor point mutation. These findings suggest genetic heterogeneity between Chinese and Japanese FCMD patients.

Child↗

PubMed2000

The Fukuyama congenital muscular dystrophy story.

Fukuyama congenital muscular dystrophy is one of the most common autosomal recessive disorders in the Japanese population, characterized by congenital muscular dystrophy in combination with cortical dysgenesis (micropolygyria). Recently, we have identified the gene responsible for fukuyama congenital muscular dystrophy on 9q31, which encodes a novel 461-amino-acid protein termed fukutin. Most Fukuyama congenital muscular dystrophy-bearing chromosomes are derived from a single ancestral founder (87%), and a 3 kb-retrotransposal insertion into the 3' untranslated region of this gene was found to be a founder mutation. Two independent point mutations causing premature termination confirmed that that this gene is responsible for Fukuyama congenital muscular dystrophy. Fukuyama congenital muscular dystrophy is the first human disease to be caused by an ancient retrotransposal integration. Fukutin contains an amino-terminal signal sequence, which together with results from transfection experiments suggests that it is an extracellular protein. Discovery of the Fukuyama congenital muscular dystrophy gene represents an important step toward greater understanding of the pathogenesis of muscular dystrophies and also of normal brain development.

Brain↗

PubMed2000

The spike of S phase cyclin Cig2 expression at the G1-S border in fission yeast requires both APC and SCF ubiquitin ligases.

We describe a novel set of oscillation mechanisms for the fission yeast S phase cyclin Cig2, which contains an authentic destruction box and is destroyed at anaphase via the APC/cyclosome (APC/C). Unlike the mitotic cyclin Cdc13, however, Cig2 mRNA and protein peak at the G1/S boundary and decline to low levels in G2 and M phases. We show here that SCF(Pop1, Pop2) plays a role in transcriptional periodicity, as pop mutations result in constitutive cig2(+) transcripts. The instability of Cig2 during G2 and M is independent of either the APC/C or Pop1/Pop2, but requires Skp1, a core component of SCF. These data indicate that the APC/C and SCF control Cig2 levels differentially at different stages of the cell cycle.

Anaphase↗

PubMed2000

Structural basis for the diversity of DNA recognition by bZIP transcription factors.

The basic region leucine zipper (bZIP) proteins form one of the largest families of transcription factors in eukaryotic cells. Despite relatively high homology between the amino acid sequences of the bZIP motifs, these proteins recognize diverse DNA sequences. Here we report the 2.0 A resolution crystal structure of the bZIP motif of one such transcription factor, PAP1, a fission yeast AP-1-like transcription factor that binds DNA containing the novel consensus sequence TTACGTAA. The structure reveals how the Pap1-specific residues of the bZIP basic region recognize the target sequence and shows that the side chain of the invariant Asn in the bZIP motif adopts an alternative conformation in Pap1. This conformation, which is stabilized by a Pap1-specific residue and its associated water molecule, recognizes a different base in the target sequence from that in other bZIP subfamilies.

Amino Acid Sequence↗