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Biomedical subjects

J Hayashi

Publications and source records attributed to J Hayashi.

At least 469 records · Page 26Linked to original sources
PubMed1983

Electrophysiologic and myocardial metabolic changes in the acute phase of partial coronary occlusion.

The acute effects of the partial reduction of coronary blood flow (CBF) on electrical and metabolic changes in myocardium were studied in 59 dogs. In seven dogs with a CBF reduction of 20% to 49%, the adenosine triphosphate (ATP) content (3.59 +/- 0.45 mumol/gm) and the width of the composite electrogram (54 +/- 5 msec) were not significantly different from those of 14 control dogs. In 14 dogs with a CBF reduction of 50% to 74%, ATP decreased significantly (3.09 +/- 0.30 mumol/gm, p less than 0.01); however, widening of the composite electrogram was not noted. Malignant ventricular arrhythmias developed in 5 of 10 dogs with a CBF reduction of 75% to 90% and 6 of 14 dogs with a 100% occlusion, but in none of the dogs with a CBF reduction of less than 75%. Marked widening of the composite electrogram (94 +/- 42 msec, p less than 0.05; and 115 +/- 54 msec, p less than 0.001) and further decrease in ATP (2.49 +/- 0.28 mumol/gm, p less than 0.001; and 2.66 +/- 0.45 mumol/gm, p less than 0.05) were noted in these two groups with a CBF reduction of greater than or equal to 75%. In conclusion, more advanced ischemia was mandatory for electrical derangements than for metabolic deterioration.

Adenosine Triphosphate↗
PubMed1983

Effect of mitochondrial DNA composition on the cellular properties of interspecific hybrid cells.

Four subclones with single species of mitochondria and three subclones with both parental mitochondria were isolated from a mouse-rat hybrid cell line H2. The effects of the coexistence of different species of mitochondria on cellular properties were examined in these clones. Growth properties were studied by comparing the plating efficiencies and doubling times. The numbers of growing colonies and the doubling times of all the subclones were found to be almost the same, indicating that these growth properties were not affected by the presence of both mouse and rat mitochondria within the cells. The correlation between the expression of chloramphenicol (CAP)-resistance and the relative contents of mtDNA of CAP-resistant (CAPr) rat and CAP-sensitive (CAPs) mouse parent cells in the subclones were also examined. The expression of CAP resistance was measured as the relative plating efficiency. Subclones with a high content of mtDNA from CAPr rat parent cells showed high relative plating efficiency.

Animals↗
PubMed1983

Two distinct types of mitochondrial DNA segregation in mouse-rat hybrid cells. Stochastic segregation and chromosome-dependent segregation.

Two distinct patterns of mitochondrial DNA (mtDNA) segregation were found in different mouse-rat hybrid cell lines. On mouse-rat hybrid cell line, H2, retained complete sets of chromosomes and mtDNAs of both mouse and rat. Even after cultivation for about one year after cloning, the H2 cell population still retained both parental mtDNAs. However, when mtDNAs of H2 subclones were examined, it was found that some individual cells in the H2 cell population contained only mouse or only rat mtDNA, although they still retained complete sets of both kinds of parental chromosomes. This type of mtDNA segregation, named stochastic segregation, is bidirectional and may be caused by the repetition of random sharing of mouse and rat mtDNAs with daughter cells. This segregation occurred spontaneously during long-term cultivation. The second type of mtDNA segregation, named chromosome-dependent segregation, was found in the other mouse-rat hybrid cell lines that segregated either mouse or rat chromosomes. In these hybrid cells, chromosomes and mtDNA of the same species co-segregated. This second type of segregation is unidirectional. The types of mtDNA segregation appear to depend on the stability of the parental chromosomes in the hybrid cells. When both mouse and rat chromosomes retain stably, mtDNA shows stochastic segregation. On the contrary, when either species of chromosomes is segregated from the cells, mtDNA shows chromosome-dependent segregation.

Animals↗
PubMed1983

Prevalence of antibody to hepatitis A virus in Okinawa and Kyushu, Japan.

Between 1968 and 1981, a total of 1955 serum samples from healthy subjects chosen at random in seven districts of Okinawa and two districts of Kyushu were surveyed for antibody to hepatitis A virus (anti-HAV) by radioimmunoassay. Overall prevalence of anti-HAV was 55.1% in Okinawa and 35.9% in Kyushu. Prevalence of less than 10% was observed in subjects less than or equal to 14 years of age in Okinawa and less than or equal to 24 years of age in Kyushu. In three of the districts of Okinawa, second serum samples were collected after intervals of eight, 10, and 12 years, respectively. Overall prevalence of anti-HAV decreased significantly over these time periods. When the age-specific prevalence of anti-HAV on the first occasion is compared with that on the second occasion, it can be seen that there have been few new cases of hepatitis A infection. These data suggest that hepatitis A infection among children has declined dramatically in recent years, and that young people may be highly susceptible to hepatitis A virus.

Adolescent↗
PubMed1983

An epidemiologic study of hepatitis B virus in Okinawa and Kyushu, Japan.

In 1968-1981, a total of 3222 serum samples were collected from healthy subjects in Okinawa--in Ishigaki City, on Hateruma Island, and on Iriomote Island--and in Kyushu, in Fukuoka City and Nichinan City. These serum samples were tested for the presence of hepatitis B surface antigen (HBsAg) by reverse passive hemagglutination (RPHA), for antibody to hepatitis B surface antigen (anti-HBs) by passive hemagglutination (PHA) and radioimmunoassay (RIA), and for antibody to hepatitis B core antigen (anti-HBc) by RIA. Overall prevalence of HBsAg (7.5%), anti-HBs by PHA (41.0%) and RIA (56.4%), and anti-HBc (65.5%) in Okinawa was significantly higher than prevalence of HBsAg (2.4%), anti-HBs by PHA (24.7%) and by RIA (28.1%), and anti-HBc (30.9%) in Kyushu. In both areas, anti-HBc was more frequently detected than anti-HBs by both methods. In Okinawa, HBsAg was significantly more prevalent in males than in females. No significant differences by sex in other hepatitis B virus markers were found. On Iriomote Island and Ishigaki City, second samples were collected after intervals of 10 and 12 years, respectively. Over these periods, the prevalence of all hepatitis B virus markers decreased significantly for the 0-9 and 10-19 year age groups. These data suggest that hepatitis B infection among children has declined in recent years and that high prevalence of hepatitis B infection in adults may reflect high rates of infection in their childhood.

Adolescent↗
PubMed1983

Subtypes of hepatitis B surface antigen in familial clusters of hepatitis B virus carriers.

A total of 919 hepatitis B surface antigen (HBsAg) positive serum samples from Kyushu and Okinawa, Japan, were subtyped for the d, y, w, and r specificities. There was a great difference in distribution of subtypes between Kyushu, where over 70% of the samples were adr, and Okinawa, where over 70% were adw. Among 306 members of 109 families with two or more hepatitis B virus carriers, HBsAg subtype was always identical within each family, even when there had been close contact between members of families with different subtypes. These results suggest that transmission of hepatitis B virus occurred within families rather than between members of different families, even when there was close contact between members of different families.

Carrier State↗
PubMed1983

Pattern of myocardial hypertrophy as a possible determinant of abnormal Q waves in hypertrophic cardiomyopathy.

Echocardiographic and electrocardiographic findings in 74 adults with hypertrophic cardiomyopathy (HCM) were analyzed to identify the pattern of myocardial hypertrophy as a possible determinant of abnormal Q waves. The pattern of septal hypertrophy along the left ventricular long axis was divided into 3 types based on the site of maximum septal hypertrophy: basal, diffuse and apical types. Abnormal Q waves defined by the revised Minnesota Codes (either I-I, I-II or I-III) were noted in 31 cases (42%). The total incidence of abnormal Q waves in the basal type (15/26, 58%) and in the diffuse type (12/22, 55%) was significantly higher (p less than 0.001 and p less than 0.01, respectively) than that in the apical type (4/26, 15%). The abnormal Q waves defined by the strict criteria of Code I-I were significantly more prevalent (p less than 0.05) in the basal type than in the diffuse type, although there was no significant difference in the total incidence of abnormal Q waves between these 2 groups. Thirty-six patients with an extension of hypertrophy to the right ventricle (RVH) had a significantly higher incidence of abnormal Q waves than 22 patients without RVH (56% vs 27%, p less than 0.05). Furthermore, close relationships of RVH to the location of abnormal Q waves were documented. In conclusion, the abnormal Q waves in HCM may be related to the pattern of septal hypertrophy along the left ventricular long axis and to RVH.

Adult↗