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Biomedical subjects

K Hayasaka

Publications and source records attributed to K Hayasaka.

At least 163 records · Page 9Linked to original sources
PubMed1992

Fetal recruitment of anthropoid gamma-globin genes. Findings from phylogenetic analyses involving the 5'-flanking sequences of the psi gamma 1 globin gene of spider monkey Ateles geoffroyi.

We determined the nucleotide sequence of a 2.5 kb DNA fragment (1 kb is 10(3) base-pairs) that includes exon 1, intron 1 and about 1.4 kb of 5'-flanking DNA of the spider monkey gamma 1-globin pseudogene locus and compared this sequence to its homologous from other primates and rabbit. This region of the gamma 1 locus of spider monkey still retains conserved regulatory elements, suggesting that it became a pseudogene late in New World monkey phylogeny. In the 250 base-pair region immediately 5' from the transcription start site where many known regulatory elements are located, a higher rate of nucleotide substitutions occurred in the ancestral anthropoid (human, ape and monkey) lineage than in the prosimian (galago) lineage, as was also the case for non-synonymous substitutions in the coding region. The opposite pattern was observed for most other non-coding regions and for synonymous substitutions. These substitution patterns correlate with the embryonic-to-fetal transformation of the gamma-globin genes of the ancestral anthropoids. Analysis of the 5'-flanking sequences suggests that 11 gene conversion events have occurred in the anthropoid gamma-gene lineages. In the parts of the 5'-flanking region where no gene conversions have been detected, gamma 2-gene sequences have accumulated more nucleotide changes than gamma 1, which suggests that the gamma 2 gene was the more redundant duplicate that may have accumulated first the nucleotide changes responsible for the anthropoid fetal pattern of gamma-globin gene expression.

Animals↗
PubMed1992

Man's place in Hominoidea revealed by mitochondrial DNA genealogy.

Molecular biology has resurrected C. Darwin and T.H. Huxley's question about the origin of humans, but the precise branching pattern and dating remain controversial. To settle this issue, a large amount of sequence information is required. We determined mitochondrial (mt) DNA sequences for five hominoids; pygmy and common chimpanzees, gorilla, orangutan, and siamang. The common region compared with the known human sequence is 4759 bp long, encompassing genes for 11 transfer RNAs and 6 proteins. Because of the high substitution rates in mammalian mtDNA and an unprecedentedly large region compared, the sequence differences clearly indicate that the closest relatives to human are chimpanzees rather than gorilla. For dating the divergences of human, chimpanzee, and gorilla, we used only unsaturated parts of sequence differences in which the mtDNA genealogy is not obscured by multiple substitutions. The result suggests that gorilla branched off 7.7 +/- 0.7 million years (Myr) ago and human 4.7 +/- 0.5 Myr ago; the time difference between these divergences being as long as 3 Myr.

Animals↗
PubMed1992

Localization of PMP-22 gene (candidate gene for the Charcot-Marie-Tooth disease 1A) to band 17p11.2 by direct R-banding fluorescence in situ hybridization.

We mapped PMP-22 gene, candidate gene for the Charcot-Marie-Tooth disease (CMT) 1A, by direct R-banding fluorescence in situ hybridization. The signals of PMP-22 probe were localized to chromosome band 17p11.2. The present result was within the map position of the CMT 1A gene by genetic linkage analysis, and strongly indicated that PMP-22 gene is a candidate gene for the CMT 1A.

Charcot-Marie-Tooth Disease↗
PubMed1992

A case of tubulo-interstitial nephritis with exfoliative dermatitis and hepatitis due to phenobarbital hypersensitivity.

Severe exfoliative dermatitis and liver dysfunction developed in a 5-year-old girl 3 weeks after initiation of phenobarbital therapy. Liver function improved gradually after discontinuation of phenobarbital. During the convalescent stage an initially mild renal dysfunction was exacerbated by episodes of post-transfusion haemolysis. Liver biopsy revealed moderate parenchymal damage with subacute cellular infiltration. Renal biopsy demonstrated the cardinal findings of interstitial nephritis, excluding the possibility of acute tubular necrosis caused by haemolysis. Serial lymphocyte transformation studies and skin patch tests gave positive results for phenobarbital, supporting the view that these were unusual complications of phenobarbital hypersensitivity.

Chemical and Drug Induced Liver Injury↗
PubMed1992

Reexamination of the African hominoid trichotomy with additional sequences from the primate beta-globin gene cluster.

Additional DNA sequence information from a range of primates, including 13.7 kb from pygmy chimpanzee (Pan paniscus), was added to data sets of beta-globin gene cluster sequence alignments that span the gamma 1, gamma 2, and psi eta loci and their flanking and intergenic regions. This enlarged body of data was used to address the issue of whether the ancestral separations of gorilla, chimpanzee, and human lineages resulted from only one trichotomous branching or from two dichotomous branching events. The degree of divergence, corrected for superimposed substitutions, seen in the beta-globin gene cluster between human alleles is about a third to a half that observed between two species of chimpanzee and about a fourth that between human and chimpanzee. The divergence either between chimpanzee and gorilla or between human and gorilla is slightly greater than that between human and chimpanzee, suggesting that the ancestral separations resulted from two closely spaced dichotomous branchings. Maximum parsimony analysis further strengthened the evidence that humans and chimpanzees share the longest common ancestry. Support for this human-chimpanzee clade is statistically significant at P = 0.002 over a human-gorilla clade or a chimpanzee-gorilla clade. An analysis of expected and observed homoplasy revealed that the number of sequence changes uniquely shared by human and chimpanzee lineages is too large to be attributed to homoplasy. Molecular clock calculations that accommodated lineage variations in rates of molecular evolution yielded hominoid branching times that ranged from 17-19 million years ago (MYA) for the separation of gibbon from the other hominoids to 5-7 MYA for the separation of chimpanzees from humans. Based on the relatively late dates and mounting corroborative evidence from unlinked nuclear genes and mitochondrial DNA for the close sister grouping of humans and chimpanzees, a cladistic classification would place all apes and humans in the same family. Within this family, gibbons would be placed in one subfamily and all other extant hominoids in another subfamily. The later subfamily would be divided into a tribe for orangutans and another tribe for gorillas, chimpanzees, and humans. Finally, gorillas would be placed in one subtribe with chimpanzees and humans in another, although this last division is not as strongly supported as the other divisions.

Africa↗
PubMed1992

The effect of carnitine on the metabolism of valproic acid in epileptic patients.

The half-life of valproic acid (VPA) was studied in 8 epileptic and severely mental retarded patients before and after one month of carnitine supplementation. Serum carnitine concentration was significantly decreased and VPA half-life was prolonged especially in adult patients before carnitine supplementation. After the treatment with carnitine, serum carnitine concentration was increased, and prolonged half-lives of VPA were corrected near to the normal range (from 12.2 +/- 4.2 hr to 9.7 +/- 2.2 hr; p < 0.05). Controlled state of epilepsy was unchanged during the short period of observation.

Adolescent↗
PubMed1992

[Serial brain CT and 123I-IMP SPECT in a case with Creutzfeldt-Jakob disease].

Serial brain CT and 123I-IMP SPECT were examined in a case with Creutzfeldt-Jakob disease (CJD). A 61-year-old woman had the onset of progressive dementia and gait disturbance in December 1988. Then, she developed left hemiparesis and dysarthria, and rapidly fell into akinetic mutism within about 2 months. Brain CT, MRI, and CSF findings showed no definite abnormalities. In February 1989, myoclonic movements appeared in several parts of the body and EEG revealed periodic synchronous discharges. Myoclonus was observed most frequently from March to May 1989, and then reduced gradually. She died in June 1990, and the total clinical course was 19 months. Brain atrophy on CT started from about 4 months after the onset, and progressed subacutely. At the end stage of the disease, diffuse brain atrophy including the cerebellum and the brain stem on CT was observed. SPECT revealed decreased perfusion in the cerebral cortex from 5 months after the onset to the end stage, but; perfusion in the cerebellum and the basal ganglia was relatively kept even at the end stage of the disease. The results suggest that SPECT is a useful examination for presumption of the pathological processes in CJD.

Creutzfeldt-Jakob Syndrome↗
PubMed1992

[67Ga scintigraphic study of a case of recurrent extra-abdominal desmoid tumor].

A case of extra-abdominal desmoid tumor was studied with 67Ga scintigraphy. Extra-abdominal desmoid tumors show an aggressive clinical course with tendency of recurrence in high percentage. On 67Ga scintigraphy, our case revealed a hot spot which is useful of recurrence. 67Ga scintigraphic study was useful in searching for local and recurrence after surgery.

Adolescent↗
PubMed1991

Isolation and sequence determination of cDNA encoding the major structural protein of human peripheral myelin.

A full length cDNA of the major structural protein of peripheral myelin (P0 protein) has been isolated from a cDNA library of human fetus spinal cord. The clone is 1948 base pairs (bp) in length and contains a 744 bp open reading frame encoding a polypeptide of 248 residues including 29 signal peptide. The deduced amino acid sequence is highly homologous to P0 protein from other species.

Amino Acid Sequence↗
PubMed1991

The primary structure of human H-protein of the glycine cleavage system deduced by cDNA cloning.

A full-length cDNA encoding the human H-protein of the glycine cleavage system has been isolated from a lambda gt11 human fetal liver cDNA library. The cDNA insert was 1091 base pairs with an open reading frame of 519 base pairs which encoded a 125-amino acid mature human H-protein with a 48-amino acid presequence. Human H-protein is 97%, 86%, and 46% identical to the bovine, chicken, and pea H-protein, respectively.

Amino Acid Oxidoreductases↗
PubMed1991

Heteroplasmy and polymorphism in the major noncoding region of mitochondrial DNA in Japanese monkeys: association with tandemly repeated sequences.

We have sequenced the major noncoding region of mitochondrial DNA (mtDNA) of four Japanese monkeys and have found length polymorphism in the sequenced region. The length polymorphism resulted from two tandem duplications of 160-bp sequences which contained the conserved sequence blocks 2 and 3 and the light-strand transcription-promoter region. We also found polymorphisms in this mtDNA region among 100 Japanese monkeys from 12 localities, 90 of which were analyzed using DNA amplified through the polymerase chain reaction. In two localities, we found individuals with heteroplasmic mtDNA which had different numbers of the 160-bp repeats mentioned above. The 100 samples were classified into six types in terms of length and presence/absence of the recognition site of two restriction enzymes in the major noncoding region.

Animals↗
PubMed1990

Restriction fragment length polymorphisms among Japanese detected with a dihydropteridine reductase cDNA gene probe.

Using a human dihydropteridine reductase (DHPR) cDNA, the frequency of restriction fragment length polymorphisms (RFLPs) with restriction endonucleases AvaII, MspI, NcoI and HinfI was estimated in unrelated, unaffected Japanese. The allele frequencies are different from those found in Caucasians, especially with MspI and HinfI. However, approximately 60% of Japanese are heterozygous for at least one of the RFLPs and analysis of one family with DHPR deficiency was shown to be informative. RFLP linkage analysis will be useful in the Japanese population as previously reported for Caucasians.

Adult↗
PubMed1990

Mitochondrial DNA evolution in primates: transition rate has been extremely low in the lemur.

Based on mitochondrial DNA (mt-DNA) sequence data from a wide range of primate species, branching order in the evolution of primates was inferred by the maximum likelihood method of Felsenstein without assuming rate constancy among lineages. Bootstrap probabilities for the maximum likelihood tree topology among alternatives were estimated without performing a maximum likelihood estimation for each resampled data set. Variation in the evolutionary rate among lineages was examined for the maximum likelihood tree by a method developed by Kishino and Hasegawa. From these analyses it appears that the transition rate of mtDNA evolution in the lemur has been extremely low, only about 1/10 that in other primate lines, whereas the transversion rate does not differ significantly from that of other primates. Furthermore, the transition rate in catarrhines, except the gibbon, is higher than those in the tarsier and in platyrrhines, and the transition rate in the gibbon is lower than those in other catarrhines. Branching dates in primate evolution were estimated by a molecular clock analysis of mtDNA, taking into account the rate of variation among different lines, and the results were compared with those estimated from nuclear DNA. Under the most likely model, where the evolutionary rate of mtDNA has been uniform within a great apes/human clade, human/chimpanzee clustering is preferred to the alternative branching orders among human, chimpanzee, and gorilla.

Animals↗