PubMed Health⌕ Search

Biomedical subjects

S Minato

Publications and source records attributed to S Minato.

At least 19 recordsLinked to original sources
PubMed2003

Gamma-ray activity in the volcanic islands of the Southern Tyrrhenian Sea.

Field gamma-ray spectrometry was used for the quantitative assessment of U, Th and K of rocks of Stromboli, Salina, Filicuidi and Panarea (Aeolian arc of the Southern Tyrrhenian, Italy). The air absorbed dose rate was calculated from radioelement concentrations. For some rocks the gamma-ray spectra were analysed with the three photo-peak methods and the response matrix method, which converts the pulse height distribution into the true incident gamma-ray energy spectrum. The higher values of U (8.2-9.8 ppm) coincide with higher Th (20.6-27.8 ppm) concentrations associated with rocks of shoshonitic composition. The spatial variation in radioelement concentration reflects the geochemical differences among the rocks. The air absorbed dose rate varies from 25 to 215 nGy h(-1). The highest values correspond to outcrops located in the eastern part of Stromboli, where the annual effective dose equivalent reaches a value of 264 microSv.

Environmental Monitoring↗
PubMed2002

Simple soil mass balance approach to interpret the distribution of global terrestrial gamma ray dose rates in relation to geology.

A recent literature survey on natural gamma rays has yielded data on the dose rate levels above soils and rocks in the world, classified by their associated bedrock types. For comparison, the data in the Japanese Islands were also collected. The compiled results indicated a strong linear correlation between the soil and the rock dose rates. A soil-mass balance model was used to obtain the quantitative estimate of soil production and inflow rates, respectively, relative to the outflow rate. It was found from the analysis that the degree of mixing of soils, measured by the ratio between the inflow and the production rates, was fairly small in Japan compared to the world average.

Journal Article↗
PubMed2001

Natural gamma-radiation in the Aeolian volcanic arc.

Pulse-height distributions of gamma-rays, obtained with a field NaI(Tl) scintillation spectrometer in numerous sites of the Lipari and Vulcano islands (Aeolian volcanic arc, Italy), were measured to determine the U, Th and K concentrations of the bedrock and the relative values of the air absorbed dose rate. U is spatially related to both Th and K and the Th/U ratio is on average 3.1-3.5. The magmatic evolution is reflected by the concentration of the three radioelements, as they are more abundant within the more felsic units of the volcanic series. The higher values of U (15.7-20.0 ppm) coincide with higher Th (48.3-65.9 ppm) and K (4.9-6.1%) concentrations associated with rhyolitic rocks of the third cycle (< 50 ky). The air absorbed dose rate varies from 20 to 470 nGy h(-1). The highest values (> 350 nGy h(-1)) are observed on outcrops of rhyolitic obsidian lava flows. The cosmic-ray contribution is also evaluated to estimate the total background radiation dose rate.

Journal Article↗
PubMed1999

Terrestrial gamma ray dose rates of Brunei Darussalam.

GPS-indexed in-situ and car-borne survey of terrestrial gamma-ray dose rates were carried out in Brunei and adjacent areas using two portable NaI(Tl) counters. The mean and population weighted average dose rates for Brunei are 34 and 33 nGy/h, respectively. The car-borne data and the in-situ data when spectral analysed separately, were found to show fractal behaviour with D of 1.7 and 1.8, respectively. A contour map of the dose rates was also produced.

Air Pollutants, Radioactive↗
PubMed1997

Antibodies to potassium channels of PC12 in serum of Isaacs' syndrome: Western blot and immunohistochemical studies.

We investigated the pathophysiology of nerve hyperexcitability in a patient with Isaacs' syndrome, who had typical clinical and electromyographic features and responded to plasma exchange. Immunoblotting and immunohistochemistry studies showed that antibodies from this patient reacted with the lysate of a neuronal cell line (PC12). In Western blots, constituents of the patient's serum, particularly immunoglobulin M, reacted with proteins of approximately 50 and 18 kDa, whereas the control serum did not. A cross-linking study with alpha-dendrotoxin (7 kDa) showed a 57 kDa protein-peptide complex. Immunohistochemistry showed that the patient's serum reacted with PC12 cells and human intramuscular nerve axons. Our findings indicate that in Isaac's syndrome nerve hyperexcitability is the result of the immunological involvement of the voltage-dependent potassium channels located along the distal motor nerve or at the nerve terminal.

Aged↗
PubMed1997

Phylogenetic position and geographic differentiation of the Japanese dormouse, Glirulus japonicus, revealed by variations among rDNA, mtDNA and the Sry gene.

The Japanese dormouse, Glirulus Japonicus, is the only extant lineage that represents this genus and it has been classified as a single species distributed on the three main islands of Japan, namely Honshu, Shikoku and Kyushu. However, individuals collected from Fukui, Wakayama and Kochi Prefectures (southwestern part of Japan) yielded distinctly different profiles of restriction fragments of the nuclear ribosomal DNA (rDNA) spacer from those collected from Yamanashi and Nagano Prefectures (central Japan). The estimated sequence divergence between the two groups was 2.8% on average, which corresponds to a putative divergence some two million years ago. Representing mitochondrial DNA (mtDNA) sequences, 402 bases of cytochrome b gene were determined by direct sequencing and the estimated extent of the sequence divergence between the two groups was 6.5-7%. Differences between the two geographic groups were also substantial in the sequences of about 300 base-fragments from the Y-linked, sex-determining locus, Sry. To assess the phylogenetic relationships between the Japanese dormouse and members of the family Myoxidae, we compared sequences of mitochondrial 12S rRNA gene of Japanese dormice with those of the forest dormouse (Dryomys nitedula) and the common dormouse (Muscardinus avellanarins), two continental genera thought to be closely related to the genus Glirulus. The results showed that the sequences from Japanese dormice were distinct from any sequences of the two continental species and the extent of the differences were somewhat similar to that between the rat (Rattus norvegicus) and the hamster (mesocricetus auratus).

Animals↗
PubMed1997

Epidemiologic survey of Blastocystis hominis infection in Japan.

The incidence of Blastocystis hominis in a healthy population was determined by fecal examination of 6,422 Japanese and 54 resident non-Japanese who visited the St. Luke's International Hospital Health Screening Center for a routine medical check-up during a one-year period. Of the enrolled subjects, 30 Japanese (0.5%) and four non-Japanese (7.4%) had B. hominis in their stools. These individuals were asymptomatic except for one who reported flatus and one who reported mild abdominal discomfort. Statistical analysis indicated that the prevalence in the Japanese was lower than in the non-Japanese, and lower than the prevalence reported for other countries. Colonoscopic observations on seven B. hominis-positive individuals did not reveal pathogenic intestinal lesions. Several months after the first examination, 23 of the B. hominis-positive individuals, including three non-Japanese, were re-examined. Although they had not been treated with anti-B. hominis drugs, 10 individuals were now B. hominis-negative (by stool examination) and eight were passing fewer organisms. The remaining five individuals were still discharging large numbers of B. hominis. These B. hominis-positive individuals had no reported symptoms despite passing numerous organisms. Therefore, it seems that infection with B. hominis rarely gives rise to clinical symptoms. In no instance was invasion of host tissues by the organisms detected.

Adult↗
PubMed1996

Serum of Isaacs' syndrome suppresses potassium channels in PC-12 cell lines.

Blockage of K+ channels in nerve terminals by immunoglobulin is the speculated pathomechanism of Isaacs' syndrome. Using patch-clamp technique (whole-cell clamp), we investigated the effects on K+ current of serum taken from 2 patients with Isaacs' syndrome employing the clonal cell line PC-12. The addition of a patient's serum to the perfusion solution had little effect on the K+ current of P-12 cells. In contrast, K+ current was reduced by 25-80% when cells were cultured for 3-6 days with 2% serum as compared to control serum values. Suppression of the K+ current appears to develop gradually over the period of culture. Our results suggest that the pathomechanism of Isaacs' syndrome is caused by K+ channel suppression via a humoral factor(s) in the serum, which subsequently induces nerve hyperexcitability.

Adult↗
PubMed1995

Stress fractures of the medial malleolus: a case report.

The findings for stress fracture of the medial malleolus in two patients are presented. In case 1, a 54-year-old woman complained of gradual onset of pain over the medial malleolus after prolonged walking. Magnetic resonance imaging was useful in the early detection of the stress fracture of the medial malleolus. In case 2, a 16-year-old male developed stress fracture of the medial malleolus during repetitive Kendo fencing activity. Good clinical results were obtained with nonsurgical therapy.

Adolescent↗
PubMed1991

Experience of surgical treatment for craniofrontonasal dysplasia.

We present a case of a 5-year-old girl diagnosed as having craniofrontonasal dysplasia (CFND), which was first reported by Cohen in 1979. CFND is very rare and reports concerning this syndrome have never been found in Japan. In our case, frontal plagiocephaly, third degree orbital hypertelorism and clefting nasal tip coexisted. At 10 months after birth when she visited our hospital, signs of craniostenosis were not recognized and cosmetic improvement was considered the main purpose of the treatment. We performed supraorbital bar reshaping, ethmoidectomy and orbitotomy for reconstruction in one-stage at the age of five. The operation produced marked improvement in her exotropia before entering a primary school. Past reports dealing with abnormalities of the central nervous system in this syndrome are few, but agenesis of the splenium was noted in our case. This paper is a report of our findings together with some discussions in reference to the literature.

Child, Preschool↗
PubMed1990

Dynamic spectrum of airborne gamma-rays.

This note describes a method of direct measurement of airborne gamma-rays primarily from 222Rn daughters using a NaI(Tl) scintillation spectrometer with lead shields. This method has the advantage of being able to maintain the system easily compared to other usual systems including a pump. The pulse-height distributions are successively fed to a floppy disk in a personal computer every unit time. The gain shifts can be corrected automatically by a computer program. This technique would be applicable to the estimation of 222Rn daughters concentration and to examination of disequilibrium between 214Pb(RaB) and 214Bi(RaC) and of those height distribution up to about 200 m. The accuracy for estimating the concentration is as good as that of the filter method.

Air Pollutants↗
PubMed1989

Activated T cells in HTLV-I-associated myelopathy: autologous mixed lymphocyte reaction.

We examined the autologous mixed lymphocyte reaction in human T-cell lymphotropic virus type I-associated myelopathy to elucidate the known increase in spontaneous proliferation of peripheral blood lymphocytes. Proliferative responses in the autologous mixed lymphocyte reaction test were significantly increased (34,205 cpm) in cells from 9 patients with the myelopathy, as compared with findings (18,695 cpm) in the control subjects. When non-T-cell fractions were depleted from autologous mixed lymphocyte reaction cultures, proliferative responses were completely suppressed in the control subjects, while proliferation of the peripheral blood lymphocytes from the groups with the myelopathy were not affected by depletion of non-T-cell fractions. The increase in spontaneous proliferation of peripheral blood lymphocytes in patients with the myelopathy is probably not related to an increase in autologous mixed lymphocyte reactions.

Adult↗
PubMed1988

Leukoencephalopathy in HTLV-I-associated myelopathy: MRI and EEG data.

Magnetic resonance imaging (MRI) of the brain and electroencephalography (EEG) were carried out for patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). Nineteen of 22 patients (86%) had abnormalities on brain MRI and/or EEG. Thirteen patients showed high signal intensity lesions scattered in the cerebral white matter, as seen on the T2-weighted MRI images. The lesions were mostly located in the subcortical and deep cerebral white matter and were not contiguous with the lateral ventricles. Patients with abnormalities on the brain MRI had a longer duration of disease and a greater disability than did those without MRI abnormalities. The EEG records showed definite abnormalities in 9, and minor abnormalities in 5. All patients with HAM for more than 5 years showed definite evidence of cerebral involvement. Our findings strongly suggest that a multifocal pathological process over the entire CNS is probably a common occurrence in HAM.

Adult↗
PubMed1988

Expression of HTLV-I antigen in cultured peripheral blood mononuclear cells from patients with HTLV-I associated myelopathy.

The HTLV-I antigen (Ag) was detected in short-term cultured peripheral blood mononuclear cells (PBMNC) from 44% of patients with HTLV-I-associated myelopathy (HAM), using the indirect immunofluorescence method. The HTLV-I Ag-positive cells accounted for less than 4% of cultured PBMNC in all but one case. The kinetics and mechanism of HTLV-I Ag expression in cultured cells were these studied in this individual with about 20% positive cells. HTLV-I Ag was 0.3% at 6 h after the culture and the number of positive cells increased to 9.3% at 48 h. The sera from HAM patients had a suppressive effect on the expression of HTLV-I Ag in the cultured cells. This suppression was more potent in sera from patients with a high than with low antibody titer. There were no correlations between the HTLV-I Ag expression in cultured cells and the various clinical and laboratory findings, in each case.

Adult↗
PubMed1988

Elevated serum antibody titers to Epstein-Barr virus in HTLV-I-associated myelopathy (HAM).

We studied the serum antibody titers to Epstein-Barr virus (EBV) in 11 patients with HTLV-I-associated myelopathy (HAM). HAM patients showed significant increases in IgG antibodies to EBV-capsid antigen (VCA) and -early antigen (EA) and in VCA-specific IgA compared with 25 seronegative subjects. However, there were no significant differences in antibodies to EBV-nuclear antigen (EBNA) or to other viruses between the two groups. In HAM patients, altered antibody responses occurred specifically to EBV-associated antigens, not to other viruses.

Adult↗
PubMed1988

Altered subsets of peripheral blood lymphocytes in patients with HTLV-I associated myelopathy (HAM).

We studied subsets of peripheral blood lymphocytes (PBL) from 12 patients with human T-lymphotropic virus type I (HTLV-I) associated myelopathy (HAM). The percent of OKT8+ cells was significantly decreased, and the percentages of OKDR+ cells and IL-2R+ cells and the ratio of OKT4+ cells to OKT8+ cells were significantly increased compared with either HTLV-I seronegative healthy adults (controls) or HTLV-I seropositive non-HAM subjects (carriers). The subsets of PBL from eight carriers showed no differences from those in controls. The patients with HAM showed significantly higher antibody titers to HTLV-I compared with carriers. These altered PBL subsets and high HTLV-I antibody titers in the patients suggest that immune functions are in an activated state in HAM.

Adult↗