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Biomedical subjects

J Hayashi

Publications and source records attributed to J Hayashi.

At least 415 records · Page 23Linked to original sources
PubMed1987

EGF receptors on TEA3A1 endocrine thymic epithelial cells.

Thymic endocrine epithelial cell line TEA3A1 can be maintained and passaged in a serum-free WAJC404A medium supplemented with insulin, transferrin, dexamethasone and EGF. EGF not only promotes the growth of these cells but also regulates the activation of phospholipase A2 enzyme activity. The binding of [125I]EGF to the TEA3A1 cells is temperature and time dependent, saturable and can be blocked by excess unlabelled EGF. Two classes of EGF receptors are found on these cells. One with Kd of 5 X 10(-11)M (approximately 3000 sites/cell) and the other with Kd of 5 X 10(-9)M (approximately 30,000 sites/cell). The resynthesis of EGF receptor in TEA3A1 cells after down-regulation requires about 24 hrs and can be blocked by both actinomycin D and cycloheximide.

Animals↗
PubMed1987

Mitochondrial genomes in intraspecies mammalian cell hybrids display codominant or dominant/recessive behavior.

A unique type of nonstochastic mitochondrial DNA (mtDNA) segregation was found in mammalian cells. In human cell hybrids isolated from the fusion of HeLa cells with 23, GM639, A549, or 293 cells, HeLa mtDNA was always lost from the hybrids, whereas both parental mtDNAs were maintained in hybrids of HeLa X 143BTK-. Similar phenomena were observed in mouse cell hybrids isolated by the fusion of cells with different mtDNA types. Types 1, 2, and 3, can be distinguished from each other by restriction fragment-length polymorphisms. The mouse cell hybrids between cells with type 1 and type 2 mtDNA always lost type 2 mtDNA, whereas the hybrids between cells with type 2 and type 3 mtDNA retained both types stably. These observations suggest that either a codominant or a dominant/recessive relationship may be present in intraspecies mitochondrial genomes of human and mouse cells. When the mitochondrial genomes in cell hybrids are codominant, stochastic segregation occurs while nonstochastic segregation occurs when they are in the dominant/recessive relationship. These concepts may help elucidate organelle heredity in animals.

Animals↗
PubMed1987

Hepatitis B virus transmission in nursery schools.

To determine whether transmission of hepatitis B virus occurs among children in nursery schools, from 1979 to 1982, 269 children (mean age 2.9 +/- 1.4 years) attending five nursery schools in which there were hepatitis B surface antigen (HBsAg) carrier children were tested for hepatitis B markers. Fifteen children (5.6%) were positive for HBsAg. Ten were possibly infected with hepatitis B in nursery school by HBsAg carrier children with hepatitis B e antigen (HBeAg). Four became HBsAg carriers and six developed transient antigenemia. Three other children were positive for the immunoglobulin M class of antibody to hepatitis B core antigen but negative for HBsAg. It is possible that they too were infected with hepatitis B in schools. These observations indicate that hepatitis B transmission most probably occurs among children in nursery schools in which there are HBsAg carriers with HBeAg, and therefore vaccination of susceptible children is necessary.

Carrier State↗
PubMed1987

A seroepidemiologic study of hepatitis A virus infections: statistical analysis of two independent cross-sectional surveys in Okinawa, Japan.

To investigate the endemic situation of hepatitis A virus infection in the past in Okinawa, Japan, the authors analyzed two sets of cross-sectional data on age-specific prevalence of antibody to hepatitis A virus (anti-HAV) obtained in 1968-1973 and 1980-1981 by fitting a catalytic model. For these two sets of data, the asymptotic level of infectious force of hepatitis A virus, namely lambda infinity, was estimated as 0.121 and 0.149, the maximum slope of the time-dependent force of hepatitis A infection, namely alpha, was 0.566 and 0.529, and the year when the force of hepatitis A infection had decreased to the half of lambda infinity, namely beta, was 1966 and 1964, respectively. In the test for the equality of parameters for the two applications, the difference was not significant. Furthermore, the fitness of the catalytic model to the data on anti-HAV prevalence was good. The results of the analysis by fitting the catalytic model show that hepatitis A infection had been highly endemic, that is, 136 infections per 1,000 persons per year in the area studied before 1955, and it decreased rapidly during the 1960s. Since 1975, hepatitis A has been a rare disease (infection is almost zero per 1,000 persons per year) in Okinawa, Japan.

Adult↗
PubMed1987

The control of hepatitis B virus infection with vaccine in Japanese nursery schools.

In 1983, the efficacy of an inactivated hepatitis B vaccine was assessed among children in nursery schools in which there was at least one hepatitis B surface antigen-positive child with hepatitis B e antigen. Of the 496 children who completed the protocol, 243 (aged 2.7 +/- 1.1 years) in six of the nursery schools received three injections of the vaccine. In five other nursery schools, 253 children (aged 2.3 +/- 1.0 years) did not receive the vaccine and were used as the control group. No side effects resulted from vaccination. Two doses of the vaccine induced antibodies in 70.8% of the vaccinated children. A booster dose six months after the first induced antibodies in 82.3% of the recipients and markedly increased the proportion of recipients who produced high antibody titiers. Although nine (4.4%) of the 203 children in the control group (whom the authors were able to follow for 24 months) were infected with hepatitis B virus and two of them became carriers, none of the vaccine recipients were infected. The vaccine appears to be safe, immunogenic, and efficacious in preventing infection with hepatitis B virus in nursery schools.

Carrier State↗
PubMed1987

[Genetic monitoring of laboratory rat strains by restriction fragment length polymorphisms of mitochondrial DNA].

Restriction fragment length polymorphisms of rat mitochondrial DNA (mtDNA) were examined using various kinds of laboratory rat strains in Japan. The results show that mtDNA of laboratory rats, Rattus norvegicus, are highly polymorphic; at least 7 types, Aa, Ba, Bb, Cb, Dc, Eb, and Fa, were found with the use of 6 restriction enzymes, EcoR I, Hind II, Hha I, Hpa II, Taq I, and Hinf I. Types Aa, Ba, and Eb were distributed widely in several strains, whereas types Ba, Cb, Dc and Fa were limited to some specific strains. These results indicate that restriction fragment length polymorphisms of mtDNA can be applied to genetic monitoring of laboratory rat strains.

Animals↗
PubMed1987

Attenuation of hypothalamo-sympathetic hyperactivity by renal denervation in experimental hypertensive rats.

To clarify the effect of renal nerves on hypothalamic cardiovascular regulation in hypertension, posterior hypothalamus was electrically stimulated in renal denervated SHR (RD-SHR) and DOCA hypertensive (RD-DOCA) rats during recording blood pressure and sympathetic nerve activity. In urethane anesthetized SHR, mean blood pressure was not different between RD- and sham-operated SHR 48 hours after denervation, but two weeks later, blood pressure was lower in RD-SHR. Pressor and sympathetic nerve responses to hypothalamic stimulation were partly attenuated 48 hours after denervation, but two weeks later, attenuation was strong. The development of hypertension was abolished during two weeks observation in RD-SHR. In DOCA hypertensive rats, the development of hypertension was significantly inhibited by renal denervation. Pressor and sympathetic nerve responses to hypothalamic stimulation were significantly diminished in RD-DOCA rats. Water intake and urine volume was identical in both groups. These results suggest that renal denervation inhibited the development of hypertension accompanied with the inhibition of hypothalamo-sympathetic nerve system, furthermore, it is indicated that hypothalamic cardiovascular regulation controlled by afferent renal nerve could contribute to the development of hypertension in SHR and DOCA hypertensive rats.

Animals↗
PubMed1987

Central effect of captopril on baroreflex.

To clarify effect of converting enzyme inhibitors (CEI) on heart rate regulation, captopril (2 mg/kg) was injected intravenously (i.v.) with or without pretreatment of atropine and also responses to intracisternal (i.c.) injections were examined. Captopril induced bradycardia with lowering blood pressure, and this bradycardia was abolished by pretreatment of atropine. Reduction of heart rate by i.c. injection of captopril was significantly larger than those of i.v. injection. Furthermore, to determine whether CEI can modify baroreflexes centrally, the aortic depressor nerve (ADN) was stimulated electrically in captopril treated rats. Vasodepressor and sympatho-inhibitory responses induced by ADN stimulation were significantly attenuated by captopril, while the bradycardiac response was not changed. These findings suggest that captopril attenuated centrally vasodepressor and sympatho-inhibitory responses of the baroreflex and activated centrally cardiac vagal efferent activity.

Animals↗
PubMed1987

Thrombosed St. Jude Medical valve prosthesis in the right side of the heart in patients with tetralogy of Fallot.

Five patients who previously had had repair of tetralogy of Fallot underwent pulmonary valve replacement with a St. Jude Medical valve prosthesis for progressive right ventricular failure. One also underwent tricuspid valve replacement. Two of the valves subsequently became thrombotic despite anticoagulant therapy. Because of the high incidence of thrombosis, we conclude that the St. Jude Medical valve prosthesis is not a suitable prosthesis in the right side of the heart in patients with tetralogy of Fallot.

Child↗
PubMed1986

Intrafamilial transmission of adult T cell leukemia virus.

In an investigation of the mode of transmission of adult T cell leukemia virus (ATLV) in family settings, 275 male and 444 female subjects positive for antibody to ATLV-associated antigen (anti-ATLA) were studied. Their children were surveyed for anti-ATLA status. None of the 82 children of a positive father and a negative mother were positive for anti-ATLA. In contrast, the antibody prevalence among children with a positive mother and a positive or negative father was 27.9% and 19.9%, respectively. Of 39 parents who had one or more anti-ATLA-positive children less than 20 years old, 56.3% of the fathers and 97.1% of the mothers were anti-ATLA positive. Algorithm computation showed the possibility of ATLV transmission from husband to wife to be 60.8% and from wife to husband to be 0.4% over a 10-year period. These data suggest that ATLV is transmitted from mother to child and from husband to wife in family settings.

Adolescent↗
PubMed1986

Seroepidemiologic study of antibody to adult T-cell leukemia virus in Okinawa, Japan.

From 1980 to 1984, a total of 3,978 serum samples were collected from healthy subjects in the Yaeyama District of Okinawa, Japan. These serum samples were tested for presence of antibody to adult T-cell leukemia-associated antigen (anti-ATLA) by the enzyme-linked immunosorbent assay (ELISA) method. Overall prevalence of anti-ATLA was 15.3%. Standardized prevalence differed from island to island: Hateruma Island had the highest (21.2%) and Taketomi Island the lowest (6.2%). Prevalence of anti-ATLA increased with age and was significantly higher in females (18.1%) than in males (12.2%) (p less than 0.001). For subjects younger than 20 years of age, the rate of anti-ATLA in males was slightly higher than that in females. For subjects 20 years of age and over, prevalence was higher in females than in males. In all age groups 40 years and over, prevalence was significantly higher in females than in males.

Adolescent↗