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Biomedical subjects

K Omoto

Publications and source records attributed to K Omoto.

At least 91 records · Page 5Linked to original sources
PubMed1985

Reperfusion injury induced by augumented oxygen uptake in the initial reperfusion period. Possible efficacy of extreme hemodilution.

This study was designed to investigate the relationship between myocardial oxygen consumption and oxygen-induced myocardial injury. Dog hearts were exposed to 40 min normothermic ischemia and then reperfused for 10 min with three oxygenated perfusates containing different hemoglobin concentrations and with moderate hemodilution. The experimental groups consist of a moderate hemodilution group (Group M) receiving 8 g/dl of hemoglobin, an extreme hemodilution group (Group E) given 4 g/dl of hemoglobin, and a hemoglobin-free autologous plasma group (Group F). Hearts in the non-ischemic control group (Group C) were also perfused with moderate hemodilution throughout. In Group C, Group M and Group E, the O2 tension of perfusates was maintained at about 100 mmHg and in Group F, at over 300 mmHg. Oxygen extraction at 5 min after reperfusion in Group C was 14%, in Group M and Group E less than 10%, but in Group F 70%. Oxygen consumption in Group F was more than twice that in Group E and surpassed that in Group C. Group M also showed a significant increase in oxygen consumption compared with Group E at 5 min after reperfusion. Among the ischemic groups, Group E showed improvement of left ventricular function almost comparable to Group C accompanied by a rapid decrease in myocardial lactate, improved preservation of myocardial adenine nucleotides and prevention of myocardial lipid peroxidation. In contrast, Group F showed persistently higher values of lipid peroxides and lactate, the poorest recovery of adenine nucleotides, and impairment of left ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1985

Prevalence of a human retrovirus in native Japanese: evidence for a possible ancient origin.

The origin of a human retrovirus (ATLV or HTLV-I) is, at present, unknown although carriers of the virus have been found in Japan, the Caribbean basin and Africa. By means of a sero-epidemiological study, the Ainu people of Hokkaido, located in the northernmost island of Japan, were shown to have antibody to the virus in high frequency. Since the Ainu are regarded as descendants of the pre-agriculture native population of northern Japan, this finding appears to indicate that the retrovirus was already present in the aboriginal Japanese of prehistoric times.

Adolescent↗
PubMed1984

Further study on a BF silent allele.

A family was found which indicated the existence of a silent allele (BF*QO) at the locus for complement factor B. Three generations with eight members were studied. Four individuals were considered to be heterozygous for B deficiency because of unusual segregation patterns of the BF electrophoretic variants and low levels of B. Haplotype study on the other HLA-linked markers supported the presumption. No unusual products were detected by immunoblotting after sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).

Alleles↗
PubMed1984

In vitro study on contribution of oxidative metabolism of isolated rabbit heart mitochondria to myocardial reperfusion injury.

The present study was performed to clarify oxygen-induced damage following myocardial reperfusion, using three mitochondrial preparations from isolated rabbit hearts (nonischemic hearts and those subjected to 40 and 90 minutes of normothermic global ischemia). The viability of mitochondria was evaluated by adenosine triphosphate generation. The extent of mitochondrial injury produced by reactive oxygen metabolism was assessed by the intensity of hydroxyl radical signal detected with electron spin resonance spectroscopy and the reduction of coenzyme Q10 level. The greatest oxygen-induced injury was observed in 40-minute ischemic mitochondria exposed to pure oxygen. The use of superoxide dismutase and catalase satisfactorily prevented the oxygen-induced injury. Moreover, the net adenosine triphosphate generation of the 40-minute ischemic mitochondria was comparable to that of the nonischemic mitochondria without the enzymes. These results suggest that reperfusion of the ischemic myocardium with viable mitochondria is deleterious, because mitochondria are susceptible to injury resulting from oxidative metabolism, and that the use of superoxide dismutase, together with catalase, is beneficial for the restoration of cardiac function after ischemia.

Adenosine Triphosphate↗
PubMed1984

The Negritos: genetic origins and microevolution.

Genetic markers were examined on a total of 1,027 blood samples collected from the Aeta of Luzon and the Mamanwa of Mindanao as well as 4 other Negrito groups of the Philippines. Genetic distance analyses by means of Nei's method were carried out using frequency data for up to 21 polymorphic loci. The geographical distributions of protein variants showing private polymorphism were also examined. It was shown that (1) the Negrito populations examined, except the Mamanwa, form one cluster group on the dendrogram, (2) no close relationship exists between the Negritos and Africans, (3) Negritos are more closely related to south-east Asian populations than to Australian Aborigines and New Guineans. It is postulated that the Mamanwa are derived from the ancestral Proto-Malay population of late-Pleistocene Sundaland, from which the Negritos also evolved with a phenotypic specialization of small body size probably due to the adaptation to tropical rain forest.

Anthropology, Physical↗
PubMed1983

Polymorphism of the complement component C6 in Japanese.

Genetic polymorphism of human C6 was investigated in Japanese using isoelectric focusing and a specific haemolytic overlay method. Three common and six rare allotypes were identified. Five of these nine allotypes were reference-typed by the International Reference Laboratory. Five of the six rare allotypes were considered to be new. The allele frequencies were estimated in the population study as follows: C6 A 0.427, C6 B 0.483, C6 B2 0.076, and the rare alleles (A3, A21, M1, M2, B3, and B4) 0.014. Inheritance of the three common and the two rare (A3 and M1) allotypes was demonstrated in the family study. The patterns obtained by the pretreatment with neuraminidase are presented.

Alleles↗
PubMed1982

Polymorphism of properdin factor B in Japanese. Description of a rare variant and data of association with HLA and C2.

Polymorphism of the properdin factor B (BF) was investigated using an agarose gel immunofixation electrophoresis in 487 unrelated healthy adult Japanese who were already typed for HLA-A, -B, -C and C2. Besides the previously reported phenotypes in Japanese (S, FS, and F), a rare heterozygous phenotype (tentatively maned FTS) was observed once. The estimated allele frequencies for BS*S, BF*F, and FB*FT (F Tokyo) were 0.801, 0.198, and 0,001 respectively. The relative electrophoretic mobility of the variant band of type FTS was measured by Dr. G Mauff to be F 0.75. The conversion fragment Bb of the type showed a double-banded pattern. BF hemolytic activity of the FTS individual was at the same level as other phenotypes. Statistical tests for the phenotypic data of BF with HLA-A, -B, -C, and C2 indicated the presence of the following significant associations in Japanese: Aw33-BF*F, A11-BF*S, Aw24-BF*S, B15-BF*F, B17-BF*F, Bw44-BF*F, B7-BF*S, Bw52;-BF*S, BW54-BF*S, BW59-BF*S, Cw3-BF*F, C2*AT-BF*F, and C2*A'-BF*F.

Adult↗
PubMed1981

Genetic polymorphism of the complement C2 in Japanese.

Genetic polymorphism of the second component of human complement (C2) was investigated in 521 unrelated healthy adult Japanese using isoelectric focusing in polyacrylamide gel followed by a specific hemolytic overlay method. Besides the phenotypes reported previously (C, AC and BC), a relatively infrequent double-banded phenotype (tentatively named A'C) was observed. Moreover, a homozygous variant (A) and a heterozygous "double" variant (AB) were observed. The estimated frequencies for the common allele, C2c(= C2(1)), and the variant alleles, C2A, C2B(= C2(2)) and C2A' were 0.939, 0.034, 0.022, and 0.006, respectively. The results of further typing for HLA-A, -B, -C specificities indicated the presence of significant associations of C2A with HLA-B15 and with A26, and of C2B with HLA-Bw61. These findings support our previous observation that in Japanese there are allelic combinations showing linkage disequilibrium between C2 and HLA loci which are different from those in Caucasians, and that the C2 structural locus is more closely linked to HLA-B than to HLA-A. C2 hemolytic activities of each phenotypes were assayed. The mean activity of type AC sera was significantly higher than that of type C or type BC, while there were no differences in the activities among the types C, BC or A'C. Also presented are two pedigrees demonstrating the segregation of C2 with HLA alleles in which a homozygous C2 A or C2 B individual was observed.

Alleles↗