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Biomedical subjects

S Nakata

Publications and source records attributed to S Nakata.

At least 289 records · Page 16Linked to original sources
PubMed1985

Biochemical characteristics of cardiac myosin: the pH dependence of Ca-ATPase activity, and that of the absorption spectrum of 2,4,6-trinitrophenyl groups attached to myosin.

For both cardiac and skeletal myosin, the Ca-ATPase activity of myosin at acidic pH was shown to be different from that at alkaline pH, in the susceptibility to heat-inactivation, the effects of organic solvents, and the effect of trinitrophenylation of the myosin. It is therefore suggested that there are two different types of Ca-ATPase of both cardiac and skeletal myosin. Differences in the Ca-ATPase activity were also found between cardiac and skeletal myosins. (a) The Ca-ATPase activity of cardiac myosin was more susceptible to heat-inactivation at alkaline pH than at acidic pH. In contrast, the activity of skeletal myosin was more susceptible to heat-inactivation at acidic pH than at alkaline pH. (b) Dioxane weakly stimulated the activity of cardiac myosin at acidic pH, but strongly activated that of skeletal myosin at acidic pH. Acetone very strongly inhibited the activity of cardiac myosin at alkaline pH, but not so strongly that of skeletal myosin at alkaline pH. (c) Trinitrophenylation of the myosin resulted in loss of the activity optimum at acidic pH with skeletal myosin but not with cardiac myosin. As reported by Srivastava et al. (J. Biochem. 86, 725-731, 1979), 1 mol of lysine residue per mol of cardiac myosin quickly reacted with 2,4,6-trinitrobenzene sulfonate (TNBS) either in the absence or presence of inorganic pyrophosphate (PPi). However, trinitrophenyl (TNP) groups bound to cardiac myosin in the presence of PPi were significantly different, in the pH dependence of the absorption spectrum, from those bound (to cardiac myosin) in the absence of PPi.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Prevalence of antibody to human calicivirus in Japan and Southeast Asia determined by radioimmunoassay.

Three hundred ninety single sera from adults in Japan, Indonesia, Singapore, and Papua New Guinea were tested for antibodies to human calicivirus (HCV) by a radioimmunoassay blocking test. A high prevalence of antibodies was observed in samples collected in Japan and Southeast Asia. Of 240 serum specimens collected from five districts in Japan, 209 (87.1%) were positive for HCV antibodies. No striking difference in the prevalence of the antibody was seen among those districts. In sera collected in Southeast Asia, 84.0% (126 of 150) had antibodies to HCV (70% [35 of 50] in Singapore, 88% [44 of 50] in Indonesia, and 94% [47 of 50] in Papua New Guinea). These results indicate that HCV is a common infectious agent in Japan and Southeast Asia.

Adult↗
PubMed1984

A new method for the quantitative standardization of cross-sectional areas of the pulmonary arteries in congenital heart diseases with decreased pulmonary blood flow.

A new angiographic method for quantitative standardization of cross-sectional area of bilateral pulmonary arteries, the PA-index, and retrospective analysis of the PA-index in different types of operative procedures are presented. This study included 40 subjects in the normal control group, 46 patients in the tetralogy group, 26 patients in the Rastelli group, and 15 patients in the Fontan group. The normal value of the PA-index was 330 +/- 30 mm2/BSA and was consistent in a wide range of body surface areas from infancy to adolescence. The PA-index in the tetralogy and Rastelli groups ranged from 100 to 400 mm2/BSA. There were no early deaths in the tetralogy group, but the incidence of low cardiac output was higher in patients with a smaller PA-index, especially when the PA-index was less than 150 mm2/BSA. Low cardiac output was more severe in the Rastelli group. The operative mortality was significantly affected by the PA-index. In the Rastelli group, all of the patients with a PA-index of less than 200 mm2/BSA died, whereas the mortality rate in patients with a PA-index of more than 200 was only 6% (p less than 0.01). The mortality rate was not influenced by any other factors, such as aortic cross-clamp time or age at operation. In the Fontan group, two patients with a PA-index of less than 250 mm2/BSA died of severe heart failure, and 12 of 13 patients with a PA-index of more than 250 survived (p less than 0.01). Our results indicated the validity of the PA-index in predicting the postoperative prognosis of the various entities. In tetralogy, all patients with a PA-index over 100 mm2/BSA can undergo correction safely; in Rastelli operation, those with a PA-index under 200 should have a palliative procedure first, whereas those with a PA-index over 250 can be considered good candidates for the Fontan procedure. The PA-index may also serve a useful guide in comparing surgical results from different institutions with patients having anomalies of varying severity.

Adolescent↗
PubMed1983

Outbreak of infantile gastroenteritis due to type 40 adenovirus.

Genetic and antigenic characterisation was performed on a strain of adenovirus (EAd) isolated from an outbreak of gastroenteritis which occurred in an orphanage in the City of Sapporo, in the room housing the eldest children, who ranged in age from 14 to 22 months. 7 of the 11 children housed in that room had diarrhoea between July 11 and July 22, 1982. All 7 shed adenoviruses detectable by electron microscopy in their stools. Immune electron microscopy showed that all patients as well as the healthy contacts sharing the room underwent seroconversion to EAd. There was no homology, or very slight homology, between DNA of EAd and those of adenoviruses belonging to subgroups A to E. Antigenically EAd was closely related to type 40 adenovirus, so far the sole member of the newly identified subgroup F. This outbreak of gastroenteritis is the first in which the causative agent has been identified as being a member of subgroup F adenoviruses.

Adenoviridae Infections↗
PubMed1983

The polypeptide of a human calicivirus.

Viral particles morphologically resembling animals caliciviruses in the faeces of a patient with acute gastroenteritis were purified, radiolabeled with [125I], and analyzed by SDS-PAGE. A single major structural protein with a mol. mass 62,000 daltons was identified by immunoprecipitation technique. The finding is consistent with human calicivirus-like particles associated with gastroenteritis being a member of the family Caliciviridae.

Caliciviridae↗
PubMed1983

The coupling valve graft: a procedure for double-valve replacement.

Coupling valve grafting, a procedure to enlarge the annulus of the aortic valve and of the mitral valve simultaneously, is described. It consists of extending the J-shaped aortotomy through the middle of the noncoronary cusp into the superior aspect of the left atrium and down the anterior leaflet of the mitral valve. Then the mitral and aortic valves are replaced with a coupling valve graft, a vascular prosthesis attached to two prosthetic valves. This technique seems to be most suitable for patients in whom the valves of both annuli are narrow, as is often seen in aortic and mitral stenosis. Since both valve annuli can be enlarged greatly in this procedure, combinations of prosthetic valve sizes can be freely chosen for the two valves.

Adult↗
PubMed1983

Microtiter solid-phase radioimmunoassay for detection of human calicivirus in stools.

A microtiter solid-phase radioimmunoassay (RIA) was developed for detection of human calicivirus in stool specimens. Seventy-eight stool specimens were tested by RIA. All 17 specimens positive for human calicivirus by electron microscopy (EM) were also positive by RIA. In addition, of 21 specimens obtained from an outbreak of caliciviral gastroenteritis, 11 were positive by RIA but negative by EM. Of 20 specimens positive for rotavirus by EM and 20 nondiarrheic specimens with no virus, 2 and 1, respectively, were positive by RIA but were subsequently shown to be falsely positive by a blocking test. There was no cross-reaction between human and feline caliciviruses. Thus, the test was more sensitive than EM and, with an appropriate blocking test, was specific for human calicivirus. It might be especially useful for screening large numbers of stool specimens.

Caliciviridae↗
PubMed1982

Hereditary factors in the craniofacial morphology of Angle's Class II and Class III malocclusions.

We attempted to assess the role of heredity in the development of Angle's Class II and Class III malocclusions by comparing craniofacial morphologic differences between parents with Class II offspring and those with Class III offspring and by analyzing the parent-offspring correlations within each Class II and Class III malocclusion group. Lateral and frontal roentgenographic cephalograms were obtained for ninety-six patients with Class II malocclusion, 104 patients with Class III malocclusion, and their respective parents. Mean cephalometric profile diagrams were superimposed between the two groups of parents as well as between their offspring. Within the two groups, the parent-offspring correlation coefficients were computed for nineteen variables connecting cephalometric landmarks. The differences in the craniofacial complex were evident in the two groups of parents as well as in their offspring. High correlation coefficient values were seen between parents and their offspring in the Class II and Class III groups. Thus, there appears to be a strong familial tendency in the development of Class II and Class III malocclusions. We conclude that the hereditary pattern must be taken into consideration in the diagnosis and treatment of patients with these classes of malocclusion.

Adolescent↗