Search PubMed⌕ Search

Biomedical subjects

C Satoh

Publications and source records attributed to C Satoh.

At least 73 records · Page 4Linked to original sources
PubMed1990

Detection of deletions, insertions and single nucleotide substitutions in cloned beta-globin genes and new polymorphic nucleotide substitutions in beta-globin genes in a Japanese population using ribonuclease cleavage at mismatches in RNA:DNA duplexes.

The applicability of ribonuclease cleavage at mismatches in RNA:DNA duplexes (RNase cleavage method) for determining nucleotide variant rates has been examined in a Japanese population. DNA segments of various lengths obtained from 4 different regions of a normal and 3 thalassemic cloned human beta-globin genes were inserted into transcription vectors. Sense and antisense RNA probes uniformly labeled with 32P were prepared. When RNA probes of 771 nucleotides (nt) or less were hybridized with cloned DNAs and the resulting duplexes were treated with a mixture of RNases A and T1, the length of products agreed with theoretical values. Twelve possible mismatches were examined. Since both sense and antisense probes were used, uncleavable mismatches such as G:T and G:G which were made from one combination of RNA and DNA strands could be converted to the cleavable C:A and C:C mismatches, respectively, by using the opposite combination. Deletions and insertions of 1 (G), 4 (TTCT), 5 (ATTTT) and 10 (ATTTTATTTT) nt were easily detected. A polymorphic substitution of T to C at position 666 of the second intervening sequence (IVS2-666) of the beta-globin gene was detected using genomic DNAs from cell lines established from the peripheral B lymphocytes of 59 unrelated Japanese from Hiroshima or those amplified by polymerase chain reaction (PCR). The frequency of the gene with C at the IVS2-666 (allele C) was 0.48 and that of the gene with T (allele T) was 0.52. The associations of the 2 alleles were in agreement with Hardy-Weinberg proportions. No contradiction to Mendelian inheritance was observed in the results obtained from 11 family studies. Two new polymorphic substitutions of C to A and A to T were detected at nucleotide positions 1789 and 1945 from the capping site, respectively, using genomic DNAs amplified by PCR. The feasibility of the RNase cleavage method combined with PCR for large-scale screening of variation in chromosomal DNA is discussed.

Base Composition↗
PubMed1990

An improved method for the detection of genetic variations in DNA with denaturing gradient gel electrophoresis.

We have examined the feasibility of denaturing gradient gel electrophoresis (DGGE) of RNA:DNA duplexes to detect variations in genomic and cloned DNAs. The result has demonstrated that employment of RNA:DNA duplexes makes DGGE much more practical for screening a large number of samples than that of DNA:DNA heteroduplexes originally developed by Lerman et al. (1986), because preparation of RNA probes is easier than that of DNA probes. Three different 32P-labeled RNA probes were produced. Genomic or cloned DNAs were digested with restriction enzymes and hybridized to labeled RNA probes, and resulting RNA:DNA duplexes were examined by DGGE. The presence of mismatch(es) was detected as a difference in mobility of bands on the gel. The experimental conditions were determined using DNA segments from cloned normal and 3 thalassemic human beta-globin genes. The results of the experiments on the cloned DNAs suggest that DGGE of RNA:DNA duplexes will detect nucleotide substitutions and deletions in DNA. In the course of these studies, a polymorphism due to a single-base substitution at position 666 of IVS2 (IVS2-666) of the human beta-globin gene was directly identified using genomic DNA samples. A study of 59 unrelated Japanese from Hiroshima was made in which the frequency of the allele with C at IVS2-666 was 0.48 and that of the allele with T was 0.52. This approach was found to be very effective for the detection of heritable variation and should be a powerful tool for the detection of fresh mutations in DNA, which occur outside the known restriction sites.

DNA↗
PubMed1990

[The incidence and clinical significance of paraaortic lymph node metastases in patients with uterine cervical cancer].

Paraaortic lymph node dissection was performed in the treatment of patients with carcinoma of the cervix who were subjected to radical hysterectomy between June, 1982 and March, 1988 at the Department of Obstetrics and Gynecology, Hokkaido University Hospital, Sapporo, Japan. Thirteen out of 246 (5.3%) patients had metastases in the paraaortic lymph node. Of the patients with stage I carcinoma of the cervix, 1.0 per cent had positive paraaortic lymph node. Of the patients with stage II carcinoma, 4.9 per cent had metastases in the paraaortic lymph nodes, and of the stage III patients, 16.7 per cent had positive paraaortic lymph nodes. The incidence of paraaortic node involvement increased along with the advance of the disease. Of the patients with squamous cell carcinoma of the cervix, 4.6 per cent had paraaortic lymph node metastases. Of the patients with adenocarcinoma of the cervix including mixed carcinoma, 6.8 per cent had positive paraaortic node. All the patients with positive paraaortic lymph nodes had metastatic diseases in the pelvic nodes. In addition, the number of groups of positive pelvic nodes in the patients with positive paraaortic lymph nodes was significantly larger than that in those with negative paraaortic nodes. At the time of reporting, seven out of 13 patients with positive paraaortic lymph node have died of the disease. The mean survival period of those seven patients was 14.9 +/- 12.2 (mean +/- SD) months. Of the remaining six surviving patients, three have been doing well for more than three years.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1990

The children of parents exposed to atomic bombs: estimates of the genetic doubling dose of radiation for humans.

The data collected in Hiroshima and Nagasaki during the past 40 years on the children of survivors of the atomic bombings and on the children of a suitable control population are analyzed on the basis of the newly revised estimates of radiation doses. No statistically significant effects emerge with respect to eight different indicators. Since, however, it may confidently be assumed some mutations were induced, we have taken the data at face value and calculated the minimal gametic doubling doses of acute radiation for the individual indicators at various probability levels. An effort has also been made to calculate the most probable doubling dose for the indicators combined. The latter value is between 1.7 and 2.2 Sv. It is suggested the appropriate figure for chronic radiation would be between 3.4 and 4.5 Sv. These estimates suggest humans are less sensitive to the genetic effects of radiation than has been assumed on the basis of past extrapolations from experiments with mice.

Aneuploidy↗
PubMed1989

Reduced DNase I sensitivity of the rearranged c-myc gene in somatic cell hybrids between murine plasmacytoma cells and fibroblasts.

In mouse plasmacytoma (MPC) S194, the rearranged c-myc gene was much more sensitive to DNase I digestion than the nonrearranged gene. The sensitivity of the rearranged c-myc was markedly reduced to the same extent as that of the nonrearranged one in hybrids between the MPC cells and the fibroblasts, but not in a hybrid between the MPC and the spleen cells. These results suggest that trans-acting factors in fibroblasts alter the DNase I-sensitive structure of the rearranged c-myc gene.

Animals↗
PubMed1989

Point substitutions in Japanese alloalbumins.

We have completed the structural study of five rare types of inherited albumin variants (alloalbumins) discovered in the Biochemical Genetics Study of 15,581 unrelated children in Hiroshima and Nagasaki. We have also identified the structural change in five other alloalbumin specimens detected during clinical electrophoresis of sera from Japanese living near Tokyo. Each of the five albumin variants from Nagasaki and Hiroshima has a single amino acid substitution. All of these substitutions differ, and none has been reported in non-Japanese populations. No instances of proalbumin variants or of albumin B (the most frequent alloalbumins in Caucasians) were detected in the children in Hiroshima and Nagasaki. However, one instance of a variant proalbumin and two examples of albumin B occurred in Japanese from the vicinity of Tokyo. In addition a previously unreported point substitution was found in albumin Tochigi, which is present in two unrelated persons from Tochigi prefecture. Four of the point mutations in the Japanese alloalbumins are in close proximity in a short segment of the polypeptide chain (residues 354-382) in which three additional point substitutions have been reported in diverse populations. These results, combined with earlier data, suggest that point substitutions are grouped in certain segments of the albumin molecule.

Amino Acid Sequence↗
PubMed1989

Implications of the Hiroshima-Nagasaki genetic studies for the estimation of the human "doubling dose" of radiation.

Since 1946 a continuous effort to evaluate the potential genetic effects of the atomic bombs has been sustained. Observations on children born in Hiroshima and Nagasaki include sex ratio, congenital malformations, stillbirths, survival of liveborn infants, chromosomal abnormalities (sex chromosomal abnormalities and balanced chromosomal rearrangements), mutations altering protein structure or activity, and physical growth and development. There are no statistically significant differences between the children of parents who received increased amounts of radiation at the time of the bombings and those whose parents did not. However, the difference between the two sets of children is consistent with the hypothesis of a genetic effect of the exposure, but its magnitude suggests humans are not as sensitive to the genetic effects of radiation as projected from the mouse paradigm.

Adolescent↗
PubMed1988

Heterozygosity and ethnic variation in Japanese platelet proteins.

Sixty-two polypeptides visualized on silver-stained two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) preparations of platelets from 85 Japanese subjects, in total 5,252 spots, have been scored for genetic variation. Inherited variants of 11 of the polypeptides were recognized; the index of heterozygosity was 2.4% +/- 0.2%. Thus far, 10 genetic polymorphisms identified by 2-D PAGE of plasma, erythrocytes, or platelets have been identified in both Japanese and Caucasian subjects. A comparison of allele frequencies reveals four significant ethnic differences. We also observed four polypeptides exhibiting a low frequency polymorphism in one group but not in the other, as well as three polymorphisms in Caucasians for which no counterpart polypeptide has thus far been recognized in the Japanese group and, vice versa, 11 such polymorphisms in Japanese. Although a similar comparison of 7 enzyme polymorphisms studied with one-dimensional electrophoresis (1-D E) in the same populations revealed a relatively higher number of significant ethnic differences, evidence is presented that this is due primarily to the greater number of 1-D E observations entering into the calculation. It is argued that this similarity in the frequency of ethnic differences among the polypeptides studied by 2-D PAGE and by 1-D E is further evidence that the proteins revealed by 2-D PAGE do not differ greatly in their response to the interplay of mutation, selection, and drift from those revealed by 1-D E studies of plasma proteins and erythrocyte enzymes.

Alleles↗
PubMed1988

Diverse characteristics in potential waveform of His-Purkinje system--experimental and simulation studies.

Reflection to the body surface of the single beat-potentials of the His-Purkinje system (HPS) was analysed by a single beat recording of the epicardial HPS potentials from the Langendorff perfused canine heart and by the reconstruction of HPS potentials on the basis of the cable concept. Unipolar epicardial HPS potentials from 8 leads distributed equidistantly over the basal region of the ventricles were amplified by a high gain (120 dB) amplifiers with an active bandpass filter (40-2400 kHz). The waveform of these HPS potentials differed in each lead. The largest (42 +/- 8 microV, mean +/- SE, n = 5) of these HPS potentials, which was obtained from the anterior free wall of the right ventricle, was composed of two peaks: the initial slow- and positive-peak and the late sharp- and negative-peak. The former peak appeared 12 +/- 3 msec (mean +/- SE, n = 5) ahead of the spike of the His-bundle electrogram (HBE) recorded from the close bipolar electrodes which were attached intracavitally along the membrane portion of the His-bundle. The latter appeared in coincidence with the spike of HBE. The extracellular potentials generated by HPS excitation were calculated by assuming that the excitation proceeds along the three dimensionally reconstructed HPS. The simulated waveform was in agreement with those of the epicardial HPS potentials. Thus, the HPS potentials on the body surface may inscribe a diverse waveform as a reflection of the complexed architecture of the whole HPS.

Action Potentials↗
PubMed1988

Protein variants in Hiroshima and Nagasaki: tales of two cities.

The results of 1,465,423 allele product determinations based on blood samples from Hiroshima and Nagasaki, involving 30 different proteins representing 32 different gene products, are analyzed in a variety of ways, with the following conclusions: (1) Sibships and their parents are included in the sample. Our analysis reveals that statistical procedures designed to reduce the sample to equivalent independent genomes do not in population comparisons compensate for the familial cluster effect of rare variants. Accordingly, the data set was reduced to one representative of each sibship (937,427 allele products). (2) Both chi 2-type contrasts and a genetic distance measure (delta) reveal that rare variants (P less than .01) are collectively as effective as polymorphisms in establishing genetic differences between the two cities. (3) We suggest that rare variants that individually exhibit significant intercity differences are probably the legacy of tribal private polymorphisms that occurred during prehistoric times. (4) Despite the great differences in the known histories of the two cities, both the overall frequency of rare variants and the number of different rare variants are essentially identical in the two cities. (5) The well-known differences in locus variability are confirmed, now after adjustment for sample size differences for the various locus products; in this large series we failed to detect variants at only three of 29 loci for which sample size exceeded 23,000. (6) The number of alleles identified per locus correlates positively with subunit molecular weight. (7) Loci supporting genetic polymorphisms are characterized by more rare variants than are loci at which polymorphisms were not encountered. (8) Loci whose products do not appear to be essential for health support more variants than do loci the absence of whose product is detrimental to health. (9) There is a striking excess of rare variants over the expectation under the neutral mutation/drift/equilibrium theory. We suggest that this finding is primarily due to the relatively recent (in genetic time) agglomeration of previously separated tribal populations; efforts to test for agreement with the expectations of this theory by using data from modern cosmopolitan populations are exercises in futility. (10) All of these findings should characterize DNA variants in exons as more data become available, since the finding are the protein expression of such variants.

Alleles↗
PubMed1988

Search for mutations altering protein charge and/or function in children of atomic bomb survivors: final report.

A sample of (1) children whose parents had been proximally exposed (i.e., less than 2,000 m from the hypocenter) at the time of the atomic bombings of Hiroshima and Nagasaki and (2) a suitable comparison group have been examined for the occurrence of mutations altering the electrophoretic mobility or activity of a series of 30 proteins. The examination of the equivalent of 667,404 locus products in the children of proximally exposed persons yielded three mutations altering electrophoretic mobility; the corresponding figure for the comparison group was three mutations in 466,881 tests. The examination of a subset of 60,529 locus products for loss of enzyme activity in the children of proximally exposed persons yielded one mutation; no mutations were encountered in 61,741 determinations on the children of the comparison group. When these two series are compared, the mutation rate observed in the children of proximally exposed persons is thus 0.60 x 10(-5)/locus/generation, with 95% confidence intervals between 0.2 and 1.5 x 10(-5), and that in the comparison children is 0.64 x 10(-5)/locus/generation, with 95% intervals between 0.1 and 1.9 x 10(-5). The average conjoint gonad doses for the proximally exposed parents are estimated to be 0.437 Gy of gamma radiation and 0.002 Gy of neutron radiation. If a relative biological effectiveness of 20 is assigned to the neutron radiation, the combined total gonad dose for the parents becomes 0.477 Sv. (Organ absorbed doses are expressed in gray [1 Gy = 100 rad]; where dose is a mixture of gamma and neutron radiation, it is necessary because of the differing relative biological effectiveness of gamma and neutron radiation to express the combined gamma-neutron gonad exposures in sieverts [1 Sv = 100 rem]).

Enzymes↗
PubMed1987

Amino acid substitutions in inherited albumin variants from Amerindian and Japanese populations.

We report an effort to determine the basis for the altered migration of seven inherited albumin variants detected by one-dimensional electrophoresis in population surveys involving tribal Amerindians and Japanese children. An amino acid substitution has thus far been determined for four of the variants. The randomness in the albumin polypeptide of these and the other sixteen independently ascertained amino acid substitutions of albumin and proalbumin thus far established was analyzed; the clustering of eight of these at two positions in the six-amino acid propeptide sequence seems noteworthy. By comparison with other proteins studied by electrophoresis, albumin exhibits "average" variability. It is a paradox that individuals who, for genetic reasons, lack albumin exhibit no obvious ill effects; yet, electrophoretic variants of albumin are no more numerous than are variants of proteins, the absence of which results in severe disease.

Albumins↗
PubMed1986

Characterization of three electrophoretic variants of human erythrocyte triosephosphate isomerase found in Japanese.

Three new electrophoretic variants of human erythrocyte triosephosphate isomerase (TPI) have been partially purified and compared with the normal isozyme with respect to stability, kinetics, and immunological properties. TPI 2HR1, an anodally migrating variant, was less stable than normal in guanidine denaturation and thermodenaturation tests, although it exhibited normal kinetic properties. The level of enzyme activity in erythrocytes from the proband with the phenotype TPI 1-2HR1 was about 60% of the normal mean. The variant allozyme TPI 2NG1, an anodally migrating allozyme associated with normal activity, was very thermolabile at 55 and 57 degrees C. It was also much more labile than normal in stability tests in buffers at pH 5 and pH 10, although it exhibited normal kinetic and immunological properties. TPI 4NG1, a cathodally migrating variant associated with normal activity and normal kinetic as well as immunological properties, was more stable than normal in pH 5 buffer. Family studies demonstrated that the unique characteristics of these variants are genetically transmitted. In two-dimensional electrophoresis of purified isozymes the variant subunits were separated from the normal in the pI axis. However, there is no difference between the variants and the normal in the molecular weight axis, suggesting that the variants result from single amino acid substitutions.

Carbohydrate Epimerases↗
PubMed1986

The rate with which spontaneous mutation alters the electrophoretic mobility of polypeptides.

Studies of a Japanese population, involving a total of 539,170 locus tests distributed over 36 polypeptides, yielded three presumptive spontaneous mutations altering the electrophoretic mobility of the polypeptide. This corresponds to a mutation rate of 0.6 X 10(-5) per locus per generation. The a priori probability that undetected discrepancies between legal and biological parentage might in our test system result in an apparent electrophoretic mutation in this population is calculated to be only 0.3 X 10(-7) per locus per generation. Since electrophoresis only detects about half of the amino acid substitutions due to mutations of nucleotides, the corrected rate for mutations causing amino acid substitutions in polypeptides is 1.2 X 10(-5) per locus per generation. With allowance for synonymous mutations and those resulting in stop codons, the total mutation rate for nucleotide changes in the exons encoding a polypeptide becomes approximately equal to 1.8 X 10(-5) per locus per generation. When the present observations are combined with all of the other available data concerning mutation resulting in electrophoretic variants, the electrophoretic rate drops to 0.3 X 10(-5) per locus per generation, the total locus rate drops to roughly 1.0 X 10(-5), and the nucleotide rate drops to 1 X 10(-8). Even with this lower estimate, given approximately equal to 2 X 10(9) nucleotides in the haploid genome and an average of 10(3) exon nucleotides per polypeptide encoded, the implication, if these exon rates can be generalized, is of approximately equal to 20 nucleotide mutations per gamete per generation. This estimate of the frequency of "point" mutations does not include small duplications, rearrangements, or deletions resulting from unequal crossing-over, transcription errors, etc.

Child↗
PubMed1986

Inherited electrophoretic variants detected in a Japanese population with two-dimensional gels of erythrocyte lysates.

Genetic variation has been studied in erythrocyte lysates from 100 Japanese children and their parents by means of two-dimensional polyacrylamide gel electrophoresis. Fifty-five polypeptides selected without respect to variability were considered suitable for scoring. Genetic variation was encountered in 14 of these polypeptides. Family data show that the segregation of 13 variants is consistent with an autosomal codominant mode of inheritance; the remaining variant exhibits a sex-linked mode of inheritance. Of 8 presumably identical polypeptides found variable in Japanese and/or Caucasians, differences in the occurrence or allele frequencies of polymorphisms were recognized for four. Contrary to the experience of some investigators, the amount of variation and the ethnic differences we are encountering indicate that two-dimensional polyacrylamide gel electrophoresis is a sensitive tool for the study of genetic events.

Alleles↗