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S Shibata

Publications and source records attributed to S Shibata.

At least 163 records · Page 9Linked to original sources
PubMed1999

A method to detect low-level 63Ni activity for estimating fast neutron fluence from the Hiroshima atomic bomb.

The Hiroshima and Nagasaki atomic bombs resulted in the worst reported exposure of radiation to the human body. The data of survivors have provided the basis for the risk estimation for ionizing radiation, and thus are widely used as the basis of radiation safety. In this report we have studied a new method to detect the low-level 63Ni activity in copper samples in order to estimate the fast neutron fluence from the Hiroshima atomic bomb. Only 0.8 x 10(-3) Bq g(-1) of 63Ni is expected to be produced by the atomic bomb in a copper sample with the 63Cu(n, p)63Ni reaction at a distance of 500 m from the hypocenter. Our method has the required level of sensitivity for determination of the fast neutron fluence out to distances of at least 500 m, and perhaps as far as 1,000 m. We have already investigated and collected some bomb-irradiated copper samples for further study.

Beta Particles↗
PubMed1999

Development of an enzyme-labeled oligonucleotide probe for detecting the Escherichia coli attaching and effacing A gene.

Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic Escherichia coli (EHEC) can produce attaching and effacing (AE) lesions on intestinal epithelium in vitro and in vivo. A gene necessary to cause the AE lesion has been identified and designated Escherichia coli attaching and effacing A (eaeA) gene. In this study, an alkaline phosphatase (ALP)-conjugated oligonucleotide probe for the eaeA gene was developed and used to detect the eaeA gene among 163 strains of classical EPEC and 25 strains of EHEC O157. The prevalence rates of eaeA gene in the strains of classical EPEC and EHEC O157 were 51.5 and 100%, respectively. The eaeA-positive rate (60.0%) in strains of class I EPEC serogroups (O26, O55, O86, O111, O119, O125, O126, O127, O128ab, and O142) was significantly higher than that (22.9%) in strains of the class II EPEC serogroups (O18, O44, O114) (P<0.01). A total of 109 eaeA-positive classical EPEC and EHEC O157 were positive for fluorescent actin staining (FAS) assay, whereas 79 eaeA-negative classical EPEC were negative. Both the sensitivity and specificity of the eaeA probe versus the FAS assay positivity were 100%. Thus, use of the ALP-conjugated oligonucleotide probe for the eaeA gene would be specific and reliable in identifying the adherence capability of EPEC and EHEC.

Adhesins, Bacterial↗
PubMed1999

Comparison of Ehrlichia muris strains isolated from wild mice and ticks and serologic survey of humans and animals with E. muris as antigen.

In metropolitan Tokyo, the Ehrlichia muris seropositivity rate of 24 wild mice was 63% in Hinohara Village, but in the surrounding areas, it was 0 to 5%. This finding suggests that the reservoir of E. muris is focal. Among the 15 seropositive mice, ehrlichiae were isolated from 9 Apodemus speciosus mice and 1 A. argenteus mouse, respectively. Five ehrlichial isolates were obtained from 10 ticks (Haemaphysalis flava) collected in Asuke Town, Aichi Prefecture, where the E. muris type strain had been isolated. These new isolates were compared with the E. muris type strain. The mouse virulence and ultrastructure of the new isolates were similar to those of the type strain, and all of them were cross-reactive with each other, as well as with the type strain, by indirect immunofluorescent-antibody test. The levels of similarity of the base sequences of the 16S rRNA gene of one of the A. speciosus isolates and one of the tick isolates to that of the E. muris type strain were 99.79 and 99.93%, respectively. We suggest that all of these isolates are E. muris; that E. muris is not limited to Eothenomys kageus but infects other species of mice; and that E. muris is present at locations other than Aichi Prefecture. It appears that H. flava is a potential vector of E. muris. Twenty (1%) of 1803 humans from metropolitan Tokyo were found to be seropositive for E. muris antibodies. A serological survey revealed that exposure to E. muris or organisms antigenically cross-reactive to E. muris occurred among dogs, wild mice, monkeys, bears, deer, and wild boars in Gifu Prefecture, nearby prefectures, and Nagoya City, central Japan. However, human beings and Rattus norvegicus rats in this area were seronegative. These results indicate broader geographic distribution of and human and animal species exposure to E. muris or related Ehrlichia spp. in Japan.

Animals↗
PubMed1999

An additional monitoring of regional cerebral oxygen saturation to HMPAO SPECT study during balloon test occlusion.

BACKGROUND AND PURPOSE: To increase the reliability of 99mTc-hexamethyl propyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) study in the evaluation of hemodynamic change with balloon test occlusion (BTO) of the internal carotid artery, we attempted to clarify the usefulness of additional monitoring of regional oxygen saturation of the brain (rSO2). METHODS: During BTO, rSO2 monitoring with transcranial near infrared spectroscopy was performed 17 times on 16 patients. Asymmetrical distribution of the tracer was classified visually as follows: group 1, little or no asymmetry, and group 2, moderate or severe asymmetry. Seven regions of interest (ROI) were defined in the middle cerebral artery area of each hemisphere, and the asymmetry index (AI)=200x(Cnon-Coccl)/(Cnon+Coccl)), where Cnon=mean counts on the nonoccluded side, and Coccl=mean counts on the occluded side were also calculated. Then, mean AI (MAI) was obtained from AI of 7 ROIs for each study. RESULTS: Of the 17 procedures, 10 BTOs were in group 1 and 5 BTOs were in group 2. Two patients did not undergo SPECT study because of the immediate appearance of a neurological deficit with BTO; they were defined as group 3. The MAI in group 1 was 2. 6+/-3.3%, which was significantly smaller than the MAI in group 2 (25.6+/-5.0%, P<0.02). The DeltarSO2 (baseline rSO2-rSO2 during ICA occlusion) with BTO in group 1 was 1.5+/-1.4% (n=10), which was statistically smaller than that in group 2 (5.5+/-1.3%, n=4, P<0.05). The DeltarSO2 in group 3 was 9.0+/-0.0% (n=2). In group 1, however, rSO2 began to decline when the stump pressure fell to 45 mm Hg and always declined when the stump pressure fell below 40 mm Hg. Furthermore, in group 1, a significant correlation was observed between the DeltarSO2 and stump pressure (r=0.85, P<0.0001). CONCLUSIONS: This preliminary study reveals that an obvious asymmetrical SPECT pattern always accompanies a profound decrease in rSO2 and that rSO2 parallels a severe reduction in stump pressure in cases exhibiting a symmetrical SPECT pattern. Thus, the cerebral oximetry sensitively reflects the cerebral oxygenation, and simultaneous measurements of rSO2 and stump pressure with 99mTc-HMPAO SPECT study apparently are useful in evaluating hemodynamic integrity with BTO.

Adolescent↗
PubMed1999

Novel assessment of acute lung injury by in vivo near-infrared spectroscopy.

We investigated the feasibility and validity of near-infrared (NIR) spectroscopy for evaluation of acute lung injury (ALI). In an in vitro model simulating the spectrophotometric characteristics of the lung, NIR spectroscopy could precisely detect changes in water volume, suggesting its ability to assess the extent of pulmonary edema caused by ALI. The different grades of ALI were induced in rats by administering oleic acid and varying the pulmonary ventilation conditions, and NIR spectroscopy was employed to determine lung water content and hemoglobin (Hb) oxygenation of the lungs. NIR spectroscopy detected increased water content even in histologically mild ALI. The changes in lung water content measured by NIR spectroscopy were significantly correlated with gravimetric lung water content (r = 0.877, p < 0.0001). Deoxy-Hb measured by NIR spectroscopy consistently reflected the histological changes in the lungs, and the deoxy-Hb levels correlated with changes in SaO2 (r = -0.798, p < 0.0001). These findings demonstrate that NIR spectroscopy can evaluate lung water content and Hb oxygenation quantitatively, and may be a useful tool for assessing pathological status in ALI.

Animals↗
PubMed1999

Prop-1 gene expression in human pituitary tumors.

A novel type of pituitary-specific transcription factor, Prophet of Pit-1 (Prop-1) gene (PROP1), expresses in just early embryonic stage in mouse and closely related as a causative gene in combined pituitary hormone deficiency. We studied PROP1 expression to further clarify its correlation with tumorigenesis and biological behavior in human pituitary adenomas. Eighteen pituitary adenomas and three normal pituitary glands were examined for the expression of PROP1 and POU1F1 by using RT-PCR Pituitary adenomas were diagnosed as non-functioning adenomas (n = 11), prolactinomas (n=5), GH-producing adenoma (n = 1) and ACTH-producing adenoma (n = 1). One of non-functioning adenomas was pituitary carcinoma with cerebellar metastasis and CSF dissemination. Our results demonstrated PROP1 expression in all pituitary tumors examined, in contrast, POU1F1 was detected in 14 of pituitary tumors. PROP1 was also expressed in normal pituitary gland, however, it was not in normal brain tissue, glioblastomas (cell lines and tumor tissues) and meningioma. Our data indicated that PROP1 expression was observed constantly both in the pituitary tumors and normal human adult pituitary tissues, suggesting that PROP1 is an essential transcriptional factor for pituitary specific gene expression in human. Therefore, detection of PROP1 might be a useful indicator for differentiating pituitary adenomas, regardless of their hormonal phenotypes, from other brain tumors.

Adenoma↗
PubMed1999

Inhibitory effect of chalcone derivatives on recombinant human aldose reductase.

More than fifty chalcone derivatives were synthesized to examine structure-activity relationships against human aldose reductase. Certain 2',4'-dihydroxychalcone derivatives inhibited human aldose reductase activities, and 2',4',2, 4-tetrahydroxychalcone and 2',4',2-trihydroxychalcone showed potent inhibitory activity with IC50 values of 7.4x10(-9) M and 1.6x10(-7) M, respectively. On the other hand, cis-form chalcones, which were isomerized from the original trans-forms by irradiation of daylight in methanol solution, promoted the activity of human aldose reductase.

Aldehyde Reductase↗
PubMed1999

Parathyroid hormone-related protein regulates proliferation of condylar hypertrophic chondrocytes.

The condylar cartilage, an important growth site in the mandible, shows characteristic modes of growth and differentiation, e.g., it shows delayed appearance in development relative to the limb bud cartilage, originates from the periosteum rather than from undifferentiated mesenchymal cells, and shows rapid differentiation into hypertrophic chondrocytes as opposed to the epiphyseal growth plate cartilage, which has resting and proliferative zones. Recently, attention has been focused on the role of parathyroid hormone-related protein (PTHrP) in modulating the proliferation and differentiation of chondrocytes. To investigate further the characteristic modes of growth and differentiation of this cartilage, we used mice with a disrupted PTHrP allele. Immunolocalization of type X collagen, the extracellular matrix specifically expressed by hypertrophic chondrocytes, was greatly reduced in the condylar cartilage of homozygous PTHrP-knockout mice compared with wild-type mice. In contrast, immunolocalization of type X collagen of the tibial cartilage did not differ. In wild-type mice, proliferative chondrocytes were mainly located in both the flattened cell layer and hypertrophic cell layer of the condylar cartilage, but were limited to the proliferative zone of the tibial cartilage. The number of proliferative chondrocytes was greatly reduced in both cartilages of homozygous PTHrP-knockout mice. Moreover, apoptotic chondrocytes were scarcely observed in the condylar hypertrophic cell layer, whereas a number of apoptotic chondrocytes were found in the tibial hypertrophic zone. Expression of the type I PTH/PTHrP receptor was localized in the flattened cell layer and hypertrophic cell layer of the condylar cartilage, but was absent from the tibial hypertrophic chondrocytes. It is therefore concluded that, unlike tibial hypertrophic chondrocytes, condylar hypertrophic chondrocytes have proliferative activity in the late embryonic stage, and PTHrP plays a pivotal role in regulating the proliferative capacity and differentiation of these cells.

Animals↗
PubMed1999

Diurnal changes in intraepithelial lymphocytes (IELs) in the small intestine of mice.

Diurnal changes in small intestinal intraepithelial lymphocytes (IELs) were examined in 8- to 10-week-old BALB/cA male mice. The ratio of T cell subsets expressing CD8 alpha alpha homodimer/CD8 alpha beta heterodimer was found to be higher in the dark period than that in the light period. Increased expression of Thy-1.2 on gamma delta T cells was also observed in the light period. No significant changes were found in other subsets. This is the first report to document diurnal changes in the small intestinal IELs in mice.

Animals↗
PubMed1999

Association of polymorphism in the NeuroD/BETA2 gene with type 1 diabetes in the Japanese.

NeuroD/BETA2, a transcription factor of the insulin gene, also plays an important role in the development of pancreatic beta-cells. Recently, the NeuroD/BETA2 gene has been mapped to the long arm of human chromosome 2 (2q32) where the IDDM7 gene has previously been mapped, implying its involvement in diabetes. To identify mutations in the NeuroD/BETA2 gene that may predispose patients to develop diabetes, we studied the gene in 50 Japanese subjects with diabetes (4 with type 1 and 46 with type 2) by the polymerase chain reaction (PCR) followed by single-strand conformation polymorphism and sequencing analyses. Further analysis was performed in 392 Japanese subjects (60 with type 1 and 158 with type 2 diabetes and 174 healthy control subjects) by mismatch PCR restriction fragment length polymorphism. We found a DNA polymorphism of the NeuroD/BETA2 gene. A nucleotide G-to-A transition results in the substitution of alanine to threonine at codon 45 (Ala45Thr). The frequencies of heterozygotes for the Ala45Thr variant were 9.8% in the control subjects, 9.5% in the patients with type 2 diabetes, and 25.0% in the patients with type 1 diabetes, a significant difference (P = 0.006). Because the variant of the NeuroD/BETA2 gene (Ala45Thr) is associated with type 1 but not type 2 diabetes, it may be implicated in the loss of pancreatic beta-cells in type 1 diabetes.

Adult↗
PubMed1999

Comparison of gene arrangements of chloroplasts between two centric diatoms, Skeletonema costatum and Odontella sinensis.

We have cloned and sequenced 3.4 kbp, 2.5 kbp, 1.9 kbp, 1.6 kbp and 0.5 kbp segments of a marine centric diatom, Skeletonema costatum, chloroplast DNA. These segments contain 28 genes. The genes which are not encoded on chloroplast genomes of chlorophyll a+b plants are found such as the psaD, ycf33, ycf35 and ycf47 genes. The gene sequences were compared with that of Odontella sinensis. At nucleic acid level, the ycf genes have lower homologies (69-87%) with O. sinensis than the other genes (78-100%), and some differences in the gene arrangement are found between two centric diatoms, O. sinensis and S. costatum.

Chloroplasts↗
PubMed1999

Effects of clotrimazole on the growth, morphological characteristics, and cisplatin sensitivity of human glioblastoma cells in vitro.

OBJECT: Clotrimazole, an antimycotic drug, inhibits proliferation of normal and cancer cells by downregulating the movement of intracellular Ca++ and K+. The authors examined the effect of clotrimazole on the growth and sensitivity to cisplatin of two human glioblastoma cell lines--A172, which has the wild-type p53 gene, and T98G, which has the mutant p53 gene in vitro. METHODS: The A172 and T98G glioblastoma cells were exposed to clotrimazole and cell growth was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium chloride colorimetric assay. Clotrimazole produced a dose-dependent inhibition of cell proliferation and caused changes in cellular structure toward a well-differentiated form. The growth inhibitory effect of clotrimazole was reversible. Western immunoblot analysis revealed a marked increase in cellular glial fibrillary acidic protein and wild-type p53 and a decrease in c-myc and c-fos oncoproteins in both cell lines treated with clotrimazole. Flow cytometric analysis revealed that clotrimazole-treated cells accumulated in the G0/G1 phase with a marked decrease in cells in the S phase; when clotrimazole was washed out from the culture medium, cells again started to proliferate, with a marked decrease in cells in the G0/G1 phase and an increase in cells in the S phase. The growth inhibitory effect of clotrimazole could not be overcome by exogenous stimulation with either epidermal growth factor or c-myc peptide. A combined treatment with clotrimazole and cisplatin significantly enhanced cell cytotoxicity compared with treatment using either drug alone. A DNA fragmentation assay showed that both clotrimazole and cisplatin induced apoptosis, which was increased in cells treated by both drugs. CONCLUSIONS: The present study indicates that clotrimazole inhibits cell proliferation accompanied by morphological changes toward differentiation of glioblastoma cells and that this drug synergistically enhances the antitumor effect of cisplatin by inducing wild-type p53-mediated apoptosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

[Intracranial and orbital extension of a nasal cavity adult T-cell leukemia: a case report].

Adult T-cell leukemia (ATL) is one kind of leukemia induced by human T lymphotropic virus type I (HTLV-I) infection. An unusual case of ATL is presented. A fifty-one-year-old male patient was admitted to our hospital because of nasal obstruction and blindness in the left eye. Imaging study revealed a mass lesion in the nasal cavity, the left paranasal sinus extending to the left orbit and intracranial frontal base. Biopsy of the mass from the paranasal sinus was carried out and the histological diagnosis was a granulomatous lesion with non-specific inflammation. The clinical impression of the lesion was lethal midline granuloma. After steroid therapy and 50 Gy of local radiotherapy, the patient's symptoms disappeared except for his blindness in the left eye. Imaging study revealed that the mass lesion had become smaller. In spite of local improvement, new lesions such as cervical lymph node swelling and multiple nodular shadows in the lung fields appeared on CT scan. Histological diagnosis of the biopsied cervical lymph node was T-cell dominant non-Hodgkin's lymphoma of the diffuse type. Serologically, anti-HTLV-I antibody was positive. Southern blot analysis of lymph node biopsy showed monoclonal proliferation of ATL cells. We made the diagnosis of our case as ATL. The patient died 16 months later despite repeated systemic chemotherapy with cyclophosphamide, vincristine, adriamycin, and prednisolone. ATL can involve the central nervous system (CNS) and manifest CNS symptoms. The neurosurgeon also should consider the CNS involvement of ATL especially in Japan.

Brain Neoplasms↗
PubMed1999

Cisplatin and infusional cytosine arabinoside for the treatment of colorectal adenocarcinoma: a phase II trial.

Based on the in vitro and in vivo synergy between cytosine arabinoside (Ara-C) and cis-diamminedichloroplatinum (cisplatin), we designed a phase II trial of Ara-C with cisplatin for patients with colorectal adenocarcinoma. Forty-eight eligible patients received continuous infusion Ara-C, 30 mg/m2/day over 72 hr, plus cisplatin, 30 mg/m2 for three doses at hours 12, 36, and 60 of the Ara-C infusion. The objective partial response rate for patients with colon carcinoma was 3% (1/32 patients; 95% CI, 0-16%) with a median response duration of 2.8 months. None of the 16 patients treated for rectal carcinoma responded. Myelosuppression was the most severe toxicity. Significant gastrointestinal and hepatic toxicities occurred in a small number of patients. Nephrotoxicity and neurotoxicity were mild. We conclude that the prolonged infusion of Ara-C in combination with divided doses of cisplatin offers no significant therapeutic advantage.

Adult↗
PubMed1999

Ets-1 transcription factor-mediated urokinase-type plasminogen activator expression and invasion in glioma cells stimulated by serum and basic fibroblast growth factors.

Overexpression of urokinase plasminogen activator (uPA) has been proposed to be one of the mechanisms by which malignant glioma cells cause pericellular proteolysis of stromal structures during brain-tissue invasion. However, knowledge about the mechanisms that regulate uPA in glioma cells is still rather scant. Growth factors, particularly epidermal growth factor and basic fibroblast growth factor (bFGF), regulate uPA synthesis in various nonglial cells. Because these factors have been associated with glioma invasion, we thought that perhaps similar events may occur in glioma cells. In this study, we demonstrate that growth factors regulate uPA gene transcription in glioma cells by induction of Ets-1 transcription factor. Serum and bFGF treatment concomitantly stimulated baseline levels of Ets-1 and uPA mRNA and protein, and this was associated with a marked increase in the migration and invasion potentials of glioma cells in vitro. Treatment of cells with antisense Ets-1 but not the control sense oligonucleotides concurrently inhibited the expression of Ets-1 and uPA, and this blocked glioma cell migration and invasion by more than 50%. In addition, medium conditioned by antisense Ets-1 oligonucleotide-treated cells showed markedly reduced uPA activity, as determined by casein zymography. These results strongly suggest that serum and bFGF control glioma invasion by inducing synthesis of Ets-1 transcription factor, which directly up-regulates expression of uPA in glioma cells. Antisense inhibition of Ets-1 expression may therefore provide a potential and exciting therapeutic target for preventing invasion by glioma cells.

Blood↗
PubMed1999

[Presurgical mapping with functional MRI: comparative study with transcranial magnetic stimulation and intraoperative mapping].

PURPOSE: The accuracy of preoperative mappings in patients with brain tumors near the central sulcus using functional magnetic resonance imaging (fMRI) or transcranical magnetic stimulation (TCS) was evaluated by comparative reference to intraoperative mapping. METHODS: The thumb movement was evoked by TCS for the mapping of the motor cortex. After the placement of the marker determined by TCS on the scalp, fMRI under motor tasks consisting of repetitive grasping was performed. For motor cortex activation, an axial oblique plane to maximize gray matter sampling in the rolandic cortex was employed in order to compare these different mapping techniques more precisely. Sixteen patients with brain tumors were included in this study. RESULTS: In nine patients, fMRI disclosed activation in one restricted gyrus or in the localized area around one restricted sulcus. Of these nine patients, preoperative TCS mapping corresponded closely with fMRI in six, while in the remaining three, the TCS marker fell between 1 and 2 cm apart from the fMRI-activated area. However, in these three patients, intraoperative electrocortical stimulation corresponded with the preoperative mapping with fMRI. In six patients, contigucus two gyri were activated by motor tasks. The TCS marker was disclosed on one of the two activated gyri. Of these six patients, the position of the TCS marker and fMRI-activated site corresponded with each other in four cases. They were found on the same gyrus but there was 1.0-2.0 cm distance between them in two cases. Intraoperative somatosensory evoked potential was monitored in two of these six cases. They corresponded well with the mapping by fMRI and TCS together. In only one patient, no significant activation area was obtained by fMRI because of excessive head motion during motor tasks. The TCS marker in this patient was identical with intraoperative electro-cortical stimulation mapping. CONCLUSION: For presurgical planning in patients with brain tumor near the central sulcus, comparative evaluation with fMRI and TCS is applicable and provides accurate functional mapping.

Adult↗
PubMed1999

[Biological rhythms and drugs].

Precise, rhythmic, daily change of the internal milieu is a conspicuous feature of all living organisms. It affects the temporal patterns of all kinds of behaviors during a day and deeply influences both the social structure and daily life of individual human beings. These daily variations arise from the internal circadian mechanisms. Three functions of the endogenous clock are discriminated; rhythm generation, entrainment to light-dark cycle and output from the clock. The endogenous clock is localized in the suprachiasmatic nucleus in mammals. Interestingly, recent papers demonstrated the widespread expression (hippocampus, cerebellum and also peripheral body) of clock genes such as mPer1 and mPer2 (homologs of the Dorsophila period gene). In this review, I describe the cellular mechanisms of circadian oscillation, entrainment and output. Serotonergic drugs and melatonin affect the light and non light-induced entrainment, and lithium and estrogen change the oscillation. Thus drugs can regulate the circadian oscillation, entrainment and outputs. Therefore, I mention the possibility that CNS drugs are useful to keep physiological homeostasis through their action on biological rhythms.

Animals↗