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Biomedical subjects

K Hayasaka

Publications and source records attributed to K Hayasaka.

At least 127 records · Page 7Linked to original sources
PubMed1995

Molecular phylogeny of gibbons inferred from mitochondrial DNA sequences: preliminary report.

We analyzed the 896 base-pair (bp) mitochondrial DNA (mtDNA) sequences for seven gibbons, representative of three out of four subgenera. The result from our molecular analysis is consistent with previous studies as to the monophyly of subgenus Hylobates species, yet the relationship among subgenera remains slightly ambiguous. A striking result of the analysis is the phylogenetic location of Kloss's gibbon (H. klossii). Kloss's gibbon has been considered to be an initial offshoot of the subgenus Hylobates because of its morphological primitiveness. However, our molecular data strongly suggest that Kloss's gibbon speciated most recently within the subgenus Hylobates.

Animals↗
PubMed1995

Congenital hypomyelination neuropathy: decreased expression of the P2 protein in peripheral nerve with normal DNA sequence of the coding region.

Congenital hypomyelination neuropathy (Lyon type) is characterized by a non-progressive clinical course and a histopathological formation of atypical onion-bulb. We have studied the immunohistochemical expression of the major peripheral myelin proteins including P0 protein, myelin basic protein (MBP) and P2 protein in three such patients. No significant difference was observed between the patients and the controls, as to the P0 and MBP staining. In contrast, P2 protein antiserum scarcely stained the patients' nerve fibers except for a few scattered adequately myelinated fibers. Assuming the pathogenetic contribution of the extremely decreased P2 protein to the disease, we investigated P2 protein gene by sequencing all coding regions but failed to detect any change in the nucleotide sequence. Further investigation including the analysis of promoter region of P2 protein gene is needed to elucidate the mechanism of congenital hypomyelination neuropathy.

Base Sequence↗
PubMed1995

Detection of neoplastic clone in the hypoplastic and recovery phases preceding acute lymphoblastic leukemia by in vitro amplification of rearranged T-cell receptor delta chain gene.

This study assessed the clonality of hypoplastic and subsequent recovery phases before the development of overt leukemia by molecular genetic analysis. We describe a boy who had transient granulocytopenia and anemia before the development of acute lymphoblastic leukemia (ALL). Initially, his bone marrow was hypocellular with 23.6% of lymphoblastic cells, whereas subsequent marrow after the administration of granulocyte colony-stimulating factor (G-CSF) appeared almost normal without any lymphoblasts. At diagnosis, we found the rearrangement of T cell receptor (TCR) delta gene in the leukemic cell DNA by Southern blot hybridization. The junctional sequence of the V delta 2-D delta 3 recombination of leukemic cells obtained by polymerase chain reaction (PCR) was used for a clonospecific probe. Using the probe, the presence of leukemic clone in the materials before and after diagnosis was examined. We found that the clonospecific probe could detect one leukemic cell in 10,000 normal cells, and we demonstrated the presence of the leukemic clone at the initial hypoplastic and the subsequent recovery phase. The PCR method is very useful to confirm the presence of leukemic clone even in a retrospective analysis using low-quality materials and may be helpful to understand the pathogenesis of a smoldering preleukemic phase.

Bone Marrow↗
PubMed1995

Isolation of cDNA encoding the human liver phosphorylase kinase alpha subunit (PHKA2) and identification of a missense mutation of the PHKA2 gene in a family with liver phosphorylase kinase deficiency.

X-linked liver glycogenosis (XLG) due to liver phosphorylase kinase (PHK) deficiency is the most frequent liver glycogen storage disease. The affected patients present in early childhood with hepatomegaly and growth retardation. We isolated and determined the structure of human liver alpha subunit of PHK (PHKA2) cDNA. The 3705 base pair open reading frame encodes a polypeptide of 1235 amino acid residues, and the deduced amino acid sequence shows 93 and 68% homology to that of rabbit liver alpha subunit of PHK and human muscle alpha subunit of PHK, respectively. We identified a missense mutation, a valine substitution for glycine at amino acid 193, in the PHKA2 gene of a family with XLG.

Amino Acid Sequence↗
PubMed1995

[Abnormality of PMP-22 gene in Japanese patients with Charcot-Marie-Tooth disease--comparison between Southern blot and polymerase chain reaction analysis in the detection of PMP-22 gene duplication].

We investigated the duplication of the PMP-22 gene in 23 Japanese patients with Charcot-Marie-Tooth disease (CMT) by Southern blot and PCR analysis. To detect duplication of the PMP-22 gene region, PMP-22 cDNA and a polymorphic marker, VAW409R3, located in the region flanking the PMP-22 gene, were used as probes for Southern blot analysis. A marker, 6G1, also located in the PMP-22 flanking region, was amplified using the quantitative PCR method. The signal intensity of the 2.8-kb and 2.7-kb bands of MspI digests probed with VAW409R3 was different in patients with duplication. The ratio of these two bands, measured by densitometry, ranged from 1.75 to 2.13 in the patients with duplication and from 1.01 to 1.15 in those without duplication and in normal controls. The signal ratio of PMP-22 to the reference marker SF85 of BamHI digests ranged from 1.15 to 1.33 in the patients with duplication and from 0.96 to 1.04 in those without duplication, when compared with normal controls assigned a value of 1.0. The ranges of the intensity in these two groups were narrow, but did not overlap. The signal ratio of the PCR products of 6G1 to reference marker D1S80 on quantitative PCR analysis was also measured. The ratio ranged between 1.67 and 2.23 with duplication and between 1.29 and 1.74 without duplication according to the results of Southern blot analysis. However, some patients exhibited overlapping signal intensity in the duplication and non-duplication ranges. Thus, these three methods each has its own advantages and disadvantages in regard to detecting duplication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Non-Hodgkin's lymphoma of stage I and II in elderly patients: a retrospective study in comparison with younger patients].

Forty-one patients with non-hodgkin's lymphoma at stages I and II who had received radiation therapy were reviewed to analyze the prognosis and prognostic factors, with the main focus on a comparison of elderly (age > 65 years) and younger patients. In terms of clinical and histological characteristics, there were no differences between the elderly and younger patients. The 5-year-survival rate (5YS) in elderly patients was 52.8%, compared with 68.6% for younger patients. In patients treated with irradiation alone, the 5YS was 49.5% in elderly patients and 22.1% in younger patients. Combination treatment consisting of irradiation and chemotherapy improved 5YS markedly to 84.9% in the younger patients, while no apparent improvement was seen in the elderly patients, in whom 5YS was 54.1%. Using Cox's multiregression life table, two prognostic factors, the presence of symptoms and LDH, were extracted and found to have a significant influence upon the survival of the elderly patients. Complete response was 90.2% in the elderly patients, although relapse was seen in 54.1% of the complete responders. Relapse occurred overwhelmingly outside the irradiated regions. Since the prognosis of elderly patients could not be improved with the current chemotherapy regimen, some different regimen must be established to lower the high relapse rate in the area outside the irradiated field.

Adolescent↗
PubMed1995

[Mutation of the myelin Po gene in hereditary motor and sensory neuropathy].

Charcot-Marie-Tooth neuropathy type 1 (CMT1) or hereditary motor and sensory neuropathy (HMSN1) is the most common inherited peripheral neuropathy. Most cases show dominant inheritance. CMT1 loci map to chromosome 17 (CMT1A), chromosome 1 (CMT1B), another unknown autosome (CMT1C) and the X chromosome (CMTX). CMT1A has been demonstrated to be associated with a large DNA duplication of 17 p11.2 including the peripheral myelin protein-22 gene (PMP22) or a point mutation of PMP22. Myelin protein zero (Po), the major structural protein of peripheral myelin, is another integral myelin membrane protein like PMP22. We have mapped the locus of the Po gene to chromosome 1q22-q23 in the region of the CMT1B locus, investigated Po as a candidate gene in three families with CMT1B and identified that Po is a gene responsible for CMT1B. Dejerine-Sottas disease (HMSN3) has been considered as another demyelinating disease. However, we have demonstrated that a de novo mutation of Po gene is responsible for some sporadic cases with HMSN3. The term "Dejerine-Sottas disease" may have represented the severely affected and sporadic cases with CMT. Identification of the primary defect in the diseases enables us to classify the peripheral neuropathies based on their etiologies.

Charcot-Marie-Tooth Disease↗
PubMed1994

Structure and chromosomal localization of the aminomethyltransferase gene (AMT)

The gene for human aminomethyltransferase (AMT), also known as the T-protein of the glycine cleavage system, was isolated from a human placental cosmid library and examined by restriction mapping, polymerase chain reaction analysis, and DNA sequencing. The gene is about 6 kb in length and consists of nine exons. The 5'-flanking region of the gene lacks typical TATAA sequence but has a single defined transcription initiation site detected by the primer extension method. Two putative glucocorticoid-responsive elements and a putative thyroid hormone-responsive element are present. The AMT gene was assigned to subband 3p21.2-p21.1 by fluorescence in situ hybridization.

Amino Acid Metabolism, Inborn Errors↗
PubMed1994

Molecular evidence on primate phylogeny from DNA sequences.

Evidence from DNA sequences on the phylogenetic systematics of primates is congruent with the evidence from morphology in grouping Cercopithecoidea (Old World monkeys) and Hominoidea (apes and humans) into Catarrhini, Catarrhini and Platyrrhini (ceboids or New World monkeys) into Anthropoidea, Lemuriformes and Lorisiformes into Strepsirhini, and Anthropoidea, Tarsioidea, and Strepsirhini into Primates. With regard to the problematic relationships of Tarsioidea, DNA sequences group it with Anthropoidea into Haplorhini. In addition, the DNA evidence favors retaining Cheirogaleidae within Lemuriformes in contrast to some morphological studies that favor placing Cheirogaleids in Lorisiformes. While parsimony analysis of the present DNA sequence data provides only modest support for Haplorhini as a monophyletic taxon, it provides very strong support for Hominoidea, Catarrhini, Anthropoidea, and Strepsirhini as monophyletic taxa. The parsimony DNA evidence also rejects the hypothesis that megabats are the sister group of either Primates or Dermoptera (flying lemur) or a Primate-Dermoptera clade and instead strongly supports the monophyly of Chiroptera, with megabats grouping with microbats at considerable distance from Primates. In contrast to the confused morphological picture of sister group relationships within Hominoidea, orthologous noncoding DNA sequences (spanning alignments involving as many as 20,000 base positions) now provide by the parsimony criterion highly significant evidence for the sister group relationships defined by a cladistic classification that groups the lineages to all extant hominoids into family Hominidae, divides this ape family into subfamilies Hylobatinae (gibbons) and Homininae, divides Homininae into tribes Pongini (orangutans) and Hominini, and divides Hominini into subtribes Gorillina (gorillas) and Hominina (humans and chimpanzees). A likelihood analysis of the largest body of these noncoding orthologues and counts of putative synapomorphies using the full range of sequence data from mitochondrial and nuclear genomes also find that humans and chimpanzees share the longest common ancestry.

Animals↗
PubMed1994

Elevated expression of messenger RNA for peripheral myelin protein 22 in biopsied peripheral nerves of patients with Charcot-Marie-Tooth disease type 1A.

The human peripheral myelin protein 22 (PMP-22) gene has been mapped to chromosome 17p11.2 in the duplicated region associated with Charcot-Marie-Tooth disease type 1A. Southern blot analysis using PMP-22 as a probe indicated that the PMP-22 gene was duplicated in 5 patients from unrelated Japanese families with Charcot-Marie-Tooth disease type 1. In order to investigate whether or not an extra copy of PMP-22 has an effect on its gene expression, we analyzed relative expression of messenger RNA for PMP-22 and protein 0 (P0) against beta-actin by Northern blotting in biopsied nerves of the patients with type 1A disease, and compared the results with those of patients having other demyelinating neuropathies and the autopsied nerves of patients without neuropathies. The relative expression of PMP-22 messenger RNA in 5 patients with Charcot-Marie-Tooth disease type 1A was significantly higher than that in 5 patients with other demyelinating neuropathies (p < 0.05). There was no statistically significant difference in P0 expression between them. This study provided direct evidence for elevated expression of PMP-22 in peripheral nerves of patients with Charcot-Marie-Tooth disease type 1A as the result of a gene dosage effect. However, the relation between elevated expression of PMP-22 and the mechanism causing demyelination remains undetermined.

Adult↗
PubMed1994

Identification of the mutations in the T-protein gene causing typical and atypical nonketotic hyperglycinemia.

We have investigated the molecular lesions of T-protein deficiency causing typical or atypical nonketotic hyperglycinemia (NKH) in two unrelated pedigrees. A patient with typical NKH was identified as being homozygous for a missense mutation in the T-protein gene, a G-to-A transition leading to a Gly-to-Asp substitution at amino acid 269 (G269D). Sibling patients of a second family with atypical NKH had two different missense mutations in the T-protein gene (compound heterozygote), a G-to-A transition leading to a Gly-to-Arg substitution at amino acid 47 (G47R) in one allele, and a G-to-A transition leading to an Arg-to-His substitution at amino acid 320 (R320H) in the other allele. Gly 269 is conserved in T-proteins of various species, even in E. coli, whereas Gly 47 and Arg 320 are replaced by Ala and Leu, respectively, in E. coli. The mutation occurring in more conservative amino acid residues thus results in more deleterious damage to the T-protein, and gives the severe clinical phenotype, viz., typical NKH.

Adult↗
PubMed1994

Expression of P0 protein in sural nerve of a patient with hereditary motor and sensory neuropathy type III.

We present expression of Po protein and Po mRNA on the sural nerve of a patient with hereditary motor and sensory neuropathy type III. This patient was identified with a point mutation in Po gene, which resulted in the substitution of glycine for arginine in transmembrane domain of P0 protein. An electron microscopic examination revealed very thin myelinated fibers surrounded by multilamellated onion bulbs composed with greatly proliferated Schwann cells. An immunocytochemical and immunoblot analysis is showed P0 protein normally expressed in myelin on the sural nerve. By in situ hybridization, mRNA of P0 protein was detected at normal levels in Schwann cell cytoplasm. Those observations indicated that there was no truncated myelin P0 protein in peripheral nerve of this patient.

Adolescent↗
PubMed1994

Neural cell adhesion proteins and neurological diseases.

Neural cell adhesion proteins play important roles in neural development and are involved in various neurological diseases. P0, a major protein in mammalian peripheral myelin, mediates not only homophilic cell adhesion but also neurite outgrowth. The P0 glycopeptide inhibits the cell adhesion, but not the neurite outgrowth. Several point mutations of the P0 gene in human chromosome 1q22-23 were found in Charcot-Marie-Tooth (CMT) disease type 1B and Dejerine-Sottas (DS) disease. PASII/PMP22 and connexin 32 were also reported as target proteins of similar hereditary neuropathies. L1 is a large multifunctional protein involved in cell adhesion, neurite outgrowth, fasciculation, and neuronal cell migration. A short isoform of L1 localizes in non-neuronal cells in contrast to the complete L1 exclusively expressed in neurons. Recently various L1 mutations have been reported in X-linked hydrocephalus, MASA syndrome with mental retardation and spastic paraplegia type 1. Further studies on the mutations and disease phenotypes are important and interesting.

Animals↗
PubMed1994

[A family of hereditary motor and sensory neuropathy type I with a new type of myelin P0 mutation].

A 26-year-old man had complaints of insidiously progressive muscle weakness of the legs, worse in the right leg than in the left. Slight to moderate degrees of asymmetrical muscular atrophy and weakness of the distal lower limb muscles, greater in the right leg than in the left, without fasciculation, were also observed. Pes equinovarus deformity of both feet was obvious. Muscle stretch reflexes were decreased in the upper limbs and absent in the lower limbs, without pathologic reflexes. Vibratory sensation was moderately decreased in the toes. The right median and tibial motor nerve conduction velocities were 19.4 and 10.5 m/sec, respectively, with a markedly prolonged distal latency. No nerve action potentials were elicited from stimulation of the right and left sural nerves. A fascicular biopsy of the right sural nerve was performed. The myelinated fibers showing segmental de- and remyelination were frequently found in teased fiber preparations. Both demyelinated and remyelinated axons and onion-bulbs were frequently observed by light and electron microscopy in the Epon-embedded sections. Based on the neurological examinations and nerve conduction studies of the family members, an elder brother, father and grandmother of the proband were found to be affected by polyneuropathy. However, the mother, an uncle, an aunt, and a cousin of the proband were normal. Therefore, we concluded that this family had HMSN type I with autosomal dominant inheritance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Increased expression of CD48 on neutrophils activated in childhood patients with aplastic anemia.

Activation-associated antigens such as CD11b, CD14 and CD64 of neutrophils have been reported. Although CD48 is an activation antigen of lymphocytes and monocytes, whether it is an activation antigen of neutrophils has not previously been examined. Herein, using FACS analysis, we examined the expression of surface CD48 on neutrophils activated in vivo by G-CSF administered for the treatment of idiopathic aplastic anemia. CD48 expression was increased 24 h after the initial G-CSF infusion and peaked within 1 week. Within a few days after discontinuation of G-CSF administration, it returned to the pretreatment level. This indicates that CD48 is an activation antigen of neutrophils.

Adolescent↗
PubMed1994

[A familial Charcot-Marie-Tooth disease type 1B (CMTD1B) manifesting a new mutation of myelin P0 gene].

A 15-year-old girl (case 1) was admitted to our hospital because of progressive muscle weakness of the lower limbs and numbness of the upper limbs. She noted these symptoms beginning at 13 years of age. Neurological examination revealed that deep tendon reflexes were absent and hypesthesia of touch and pain sensation were distributed in a glove-and-stocking pattern. Muscle weakness and atrophy were predominantly present in the distal portions of the extremities. There were obvious pes cavus and champagne-bottle shape deformities. The motor conduction velocity of the median nerve was markedly delayed and sensory potentials were not evoked in any nerves examined. Lumbar MRI showed thickening of the nerve radices. Cranial MRI showed thickening of the acoustic nerves, as well. Histological studies of a biopsied sural nerve revealed a marked decrease in the number of myelinated and unmyelinated fibers and remarkable onion bulb formation. The patient's clinical manifestations and histological findings were more severe than that seen in the usual case of CMT1A. Her mother (case 2, 39 years old) had similar neurological and electrophysiological findings. DNA duplication encoding peripheral myelin protein 22, was not detected in either case 1 or 2. Sequencing of DNA from these patients revealed the presence of a mutant allele containing an A- to G-substitution of nucleotide 245, which replaced tyrosine with cysteine in the extracellular Ig-domain of the P0 protein.

Adolescent↗
PubMed1994

A mitochondrial tRNA(Leu)(UUR) mutation at 3,256 associated with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS).

Enzymatic and molecular analyses were conducted on the muscular tissue of a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Significant decreases in activity of complexes I and IV were found and three nucleotide substitutions in the mitochondrial tRNA genes were detected. Two of the substitutions were detected in unaffected members of the family and in some healthy controls. A C-to-T transition mutation at the nucleotide position 3,256 in the mitochondrial tRNA(Leu)(UUR) gene was detected only in the patient and not in unaffected members of the family or 100 healthy controls. The data strongly suggest that this mutation at nucleotide position 3,256 in the mitochondrial tRNA(Leu)(UUR) gene is associated with MELAS.

Adult↗