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Biomedical subjects

K Ohba

Publications and source records attributed to K Ohba.

At least 109 records · Page 6Linked to original sources
PubMed1993

Sodium valproate-induced cardiovascular abnormalities in the Jcl:ICR mouse fetus: peak sensitivity of gestational day and dose-dependent effect.

Sodium valproate was administered to Jcl:ICR mice in order to determine its effect on cardiovascular development. A single dose of 600 mg/kg of sodium valproate was injected intraperitoneally on gestational days 6, 7, 8, or 9. In same animals, a single dose of 300, 400, 500, or 700 mg/kg was injected on gestational day 7. On day 18 of gestation, dams were laparotomized to observe number of live, dead and resorbed fetuses. In addition, live fetuses were examined for cardiovascular abnormalities. Although cardiovascular abnormalities were noted in 3% of live fetuses and in 26% of litters in the group treated on day 6 (600 mg/kg), there was no significant difference from the control group, suggests that there may have been a biologically significant increase, although not a statistically significant increase. Cardiovascular abnormalities were found in 30%, 11%, and 8% of live fetuses in the groups treated with 600 mg/kg on days 7, 8, and 9, respectively. These represented a statistically significant increase in effects as opposed to the control groups. Among the varying dosages administered on day 7 of gestation, cardiovascular abnormalities occurred in 2%, 6%, 16%, and 36% of live fetuses in groups treated with 300, 400, 500, and 700 mg/kg, respectively, showing a significant dose-dependent increase. These cardiovascular abnormalities observed were divided into the following groups: ventricular septal defect, endocardial cushion defect, transposition of the great arteries, double outlet right ventricle, tricuspid atresia, and hypoplastic left heart syndrome. Maternal death did not occur at any treatment level.

Animals↗
PubMed1993

Antigenicities of Group I and II hepatitis C virus polypeptides--molecular basis of diagnosis.

Comparative nucleotide sequence studies on the putative NS3 and NS4 regions of the genomes of hepatitis C viruses (HCV) have revealed that there are at least two groups of HCV, group I and group II. The cDNA clone E, corresponding to a boundary between the NS3 and NS4 (NS3-4) region of the group II HCV genome, encodes antigens that react to antibodies specific to group II HCV (Tsukiyama-Kohara et al. (1991) Virus Genes 5, 243-254). To understand the molecular basis of the group-specific antigenicity of HCV peptides, the predicted amino acid sequences around the NS3-4 region of our group II HCV cDNAs were compared with those of other HCV isolates. The analysis revealed the presence of group-specific amino acids in this peptide region. Evolutionary analysis of nucleotide sequences within this region of these HCV isolates also led to the same classification. A similar result was obtained by sequence analysis of cloned cDNAs corresponding to the core region. A cDNA of the group II HCV core region was prepared by polymerase chain reaction from the cDNA synthesized with group II-specific primer complementary to the NS3-4 region. The products directed by the cDNA of the core region did not have group-specific antigenicity. The NS3 peptide region also appeared not to carry group-specific antigens. Our results indicate that most HCV isolates can be classified into either group I or II, and that the existence of two groups of HCV does not disturb HCV diagnosis as long as core and/or NS3 peptides are used to detect HCV antibodies.

Amino Acid Sequence↗
PubMed1993

Dynamics of genome change in the E2/NS1 region of hepatitis C virus in vivo.

To substantiate and extend the quasispecies model of hepatitis C virus (HCV), we made a pairwise comparison in the nucleotide and deduced amino acid sequences for multiple recombinant clones of the E2/NS1 region, which derived from each blood sample taken from five patients of subtype II or subtype III infection at different stages. Sequence heterogeneity among the clones was generally high. The heterogeneity, however, changed temporally and appeared to be significantly lowered after interferon therapy. The temporal fluctuation involved selection of particular amino acids at particular positions, which had represented only a minor fraction or had been absent in the previous clones. Evolution of defective viruses was featured by most of the cases, the proportion of which also fluctuated temporally and was extremely high at a certain stage in one of the patients. A comparison was also made among the clones from different stages of each patient and revealed highly divergent clones. An extreme case of subtype III infection showed sequence differences well beyond those among chronologically and geographically different isolates of subtype I or subtype II, which were defined by the same calculation of available sequence data. These features of HCV genome suggest that the virus could circulate as an extremely heterogeneous population including defective viruses and that this heterogeneity lends itself to selection pressures including interferon therapy and host immune response. Our results also indicate an absolute need of population based approach in HCV genetics.

Aged↗
PubMed1993

Molecular classification of hepatitis C virus.

Many sequences of hepatitis C virus (HCV) have been reported, but there has been no report about the evolutionary classification of HCV. The aim of this study is to classify the nucleotide sequences of HCV into appropriate genetical groups by molecular evolutionary methods. A number of nucleotide sequences of HCV were collected from all over the world. First, all HCV nucleotide sequences for each region were aligned to optimize homologies. Phylogenetic trees were then constructed for each region of HCV according to the number of the nucleotide substitutions. HCVs can be classified into two or three major groups in the trees of each regions. However, minor groups can be classified into two in that of 5' non-coding, four in that of Core, Env., E2/NS1, NS3 and NS4 region and six in that of NS5 region. However, the full sequences such as HCV-1, HCVH and HCV-J4, were always located in the same major and minor groups in that trees of all regions. These data indicated that HCVs can be classified into two or three major and six minor groups.

Base Sequence↗
PubMed1993

Hibernation-associated gene regulation of plasma proteins with a collagen-like domain in mammalian hibernators.

In mammals, hibernation is expressed by only a limited number of species, and the molecular mechanisms underlying hibernation are not well understood. Recently, we have found plasma proteins which disappear from blood specifically during hibernation in a mammalian hibernator, the chipmunk. Here, we report the cDNA cloning of these chipmunk hibernation-related proteins, HP-20, -25, and -27, and analyses of their expression. All three proteins contain a collagen-like domain near the N terminus and are highly homologous to each other. Their mRNAs were detected only in liver in nonhibernating chipmunks, and in hibernating chipmunks, the amounts were reduced to less than 1/10 of those in nonhibernating chipmunks, indicating that HP-20, -25, and -27 mRNA expression is regulated similarly in association with hibernation. Southern blot analyses of the squirrel family with each of chipmunk HP-20, -25, and -27 cDNA revealed that a nonhibernating species (tree squirrel) as well as another hibernating species (ground squirrel) retained the corresponding genes. However, their transcripts were detected only with the hibernating species, and in hibernating ground squirrels, their levels were greatly reduced compared with those in nonhibernating animals, as were the cases with the chipmunk. These observations are the first line of evidence for occurrence of hibernation-associated gene regulation. The results would indicate the commitment of HP-20, -25, and -27 to hibernation and support the idea that genetic controls are involved in mammalian hibernation.

Amino Acid Sequence↗
PubMed1993

[Analysis of bone loss with aging and menopause--using digital image processing].

To study bone loss relationships to aging and menopause, cross-sectional bone mass measurements by digital image processing (DIP method), and menopause information collected by questionnaire, were analyzed on 291 women who live in Tsukude village. The results are as follows. 1) The mean DIP values (sigma GS/D, MCI) by age-stratified groups decrease with age after menopause. The rate of bone loss in sigma GS/D is almost constant, but in MCI it increases with aging. 2) In 30-year old and 40-year old age groups, the frequency distribution of DIP values is symmetrical and bell-shaped. But after the fifties the distribution is asymmetrical, with the mode of distribution deviated toward low bone mass. The change of mode with aging is larger than that of mean. This fact suggests that change of mean bone mass substantially underestimates actual bone loss from aging. 3) The change of the mean DIP values stratified by years elapsed since menopause is not especially large at start of menopause but becomes almost constant after menopause. DIP values reflect the bone loss from the aging rather than from menopause, and are beneficial to the study of bone loss in elderly women.

Adult↗
PubMed1993

[Molecular genotypes of hepatitis C virus and their divergence times].

We collected the nucleotide sequences of hepatitis C virus (HCV) from the international DNA data base DDBJ/EMBL/GenBank to carry out molecular evolutionary analysis of HCVs. Using these sequences, we constructed the phylogenetic trees for the 5' non-coding, Core, Env., E2/NS1, NS3, NS4 and NS5 regions of HCV. The number of nucleotide substitutions per site at all positions between all pairs of HCVs, for each region, were estimated by the 6-parameter method. Using these numbers, we constructed phylogenetic trees for each region of HCV by the neighbor-joining method. In these trees for the coding regions (Core, Env, E2/NS1, NS3, NS4 and NS5 regions), HCVs can be classified into two major and four minor genotypes, but into three major and six minor genotypes on the tree of the NS5 region. It appears that HCVs exist as at least two or three major and six minor types. The evolutionary rates of HCV was estimated to be about 10(-3) per site per year close to that of human immunodeficiency virus. The new genotypes of HCV may be therefore isolated elsewhere in the near future. Then, applying the distance between H77 and H90 strains to the phylogenetic trees, we estimated the divergence times of HCVs. The major genotypes diverged about 300-400 years ago from the ancestor virus and after then, each minor genotypes diversed about 200 years ago from their major genotypes. These data suggested that HCVs spread out all over the world during these hundred years.

Base Sequence↗
PubMed1993

[Molecular evolutionary analysis of hepatitis B virus (HBV) and genetic classification].

HBsAg of Hepatitis B virus (HBV) has been classified into four major subtypes (adw, adr, ayw, ayr) by the serological methods. Using molecular evolutionary analysis technique, we constructed the phylogenetic tree for the partial S gene (HBsAg gene) of HBV. The tree shows that 51 strains of HBV can be classified into following four genetic subgroups: (1) strains of subtypes ayw and adyw, (2) those of adw and adr, (3) another of adw, and (4) other subgroup of adr, adw, ayr, ar and ad. We propose that these subgroups be designated gyw, gdw-1, gdw-2, and gdr, respectively, with "g" standing for genetic classification. It is important that the genetic classification of HBVs is not always compatible with conventional serological subtypes. It is possible that the conventional subtypes do not represent a classification according to the degree of genetic difference among strains of HBVs. Thus, our genetic classification is more suitable for studies of epidemiological and virological features of HBVs.

Amino Acid Sequence↗
PubMed1992

Etiologic and pathogenetic study of mental retardation with multiple congenital anomalies.

Etiology and pathogenesis of MCA/MR in 1,023 patients (618 male; 405 female) with mental retardation were studied. Of 1,023 patients, there were 563 cases (317 male; 246 female) with MCA (55%). Among the MCA patients, there were 303 (156 male; 147 female) whose primary etiology was clarified (53.8%). Among the 260 patients with MCA/MR of unknown etiology, there were 23 with recognizable syndromes of unknown etiology and 7 previously reported by us as possibly having a new malformation syndrome. We had 569 patients with mental retardation of unknown etiology including 263 (41.5%) who were involved with MCA.

Brain↗
PubMed1992

[Infantile spasms in monozygotic twins with Smith-Lemli-Opitz syndrome type I].

Monozygotic twins with Smith-Lemli-Opitz syndrome who developed infantile spasms were presented. They were the result of the first full-term pregnancy of non-consanguineous parents. They had following abnormalities: marked growth and developmental retardation, congenital heart disease, light brown hair which is rare in Japanese, small dolichocephaly, hypertelorism, anteverted nostrils, micrognathia, hypospadias and shawl scrotum. The cranial MRI showed the delayed myelination of occipital lobe. As far as we could review published reports, we were unable to find other report on monozygotic twins having the Smith-Lemli-Opitz syndrome.

Abnormalities, Multiple↗
PubMed1991

Prenatal diagnosis of the aneurysm of the vein of Galen by pulsed Doppler unit.

Aneurysm of the vein of Galen is a rare anomaly. In the severe type, the first clinical manifestation of this anomaly is heart failure after birth. Prenatal diagnosis is important in preventing heart failure during the postnatal period. Here, we report the prenatal diagnosis of a case of aneurysm of the vein of Galen in which we used a pulsed Doppler unit combined with a fetal electrocardiogram-phonocardiogram unit.

Adult↗
PubMed1991

Purification and properties of a novel surface-active agent- and alkaline-resistant protease from Bacillus sp. Y.

In the course of a search for an alkaline stable protease for industrial use, an alkaline protease (protease BYA) was isolated from an alkalophilic Bacillus sp. Y, and its properties were characterized. Its optimum pH was pH 10.0-12.5, when casein was used as a substrate. In addition to the stability of protease BYA at pH 6.5-13.0, it was also very stable towards various surface-active agents, such as sodium dodecyl sulfate and sodium linear alkylbenzene sulfonate. Protease BYA was most active at 70 degrees C. The isoelectric point (pI) of protease BYA was about 10.1. Protease BYA was characterized as a serine protease because of its sensitivity to phenylmethanesulfonyl fluoride and diisopropyl fluorophosphate. The protease seems to be related to proteases of the subtilisin family, such as subtilisin BPN', subtilisin Carlsberg, and No. 221 protease.

Amino Acid Sequence↗
PubMed1990

Teratogenic effects of sodium valproate in the Jcl: ICR mouse fetus.

Sodium valproate was administered to Jcl:ICR mice in order to evaluate its teratogenicity. A single dose of 600 mg/kg of sodium valproate was injected intraperitoneally on gestational day 6, 7, 8 or 9. On day 18 of gestation, dams were laparotomized, and live fetuses were inspected for the presence of external and internal abnormalities. Exencephaly and urogenital abnormalities showed the highest frequency in the group treated on day 8, being recognized in about 60% and 10% of live fetuses, respectively. Cardiovascular abnormalities were found in the highest frequency in the group treated on day 7 (in about 30% of live fetuses). Incidence of tail abnormality was found to increase with delay in day of drug administration. Other abnormalities observed were cleft palate and digital malformation. Our study showed that a constellation of major abnormalities similar to the congenital valproate syndrome suspected in humans could be produced in the Jcl:ICR mouse fetus.

Abnormalities, Drug-Induced↗
PubMed1990

Trisomy 10p syndrome owing to maternal pericentric inversion.

A female infant with karyotype 46,XX,rec(10),dup p inv(10)(p11.2q25.2)mat is presented. She had both duplication of 10p and deletion of distal 10q, but only had the constellation of specific features characteristic of duplication of 10p.

Chromosome Inversion↗