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Biomedical subjects

H Yoshioka

Publications and source records attributed to H Yoshioka.

At least 163 records · Page 9Linked to original sources
PubMed1997

Spatiotemporal ESR-CT study on the metabolism of spin-labeled polysaccharide in a mouse.

A spatiotemporal ESR-CT study, rapid three dimensional ESR imaging by which distribution and metabolism of radicals in a small region in a living body can be followed, was carried out by intravenously administering spin-labeled polysaccharides to mice. The in vivo lifetime of spin-labeled hydroxyethylstarch (TEMPO-HES) was shorter than that of spin-labeled dextran (TEMPO-DX), suggesting that the clearance of their spins depended on the stability of the polymer chains to the hydrolysis. Spatiotemporal image at the kidney domain of a mouse showed that low molecular weight TEMPO-DX was excreted into the kidney and then was transferred to the bladder. Time dependence of the ESR intensity of TEMPO-HES at certain points in the liver domain had a maximum showing that TEMPO-HES was taken into the liver and then was decomposed there by the metabolism, but the rate of decrease in the intensity was different in each part in the liver because of the difference in metabolic function. The rate of decrease of TEMPO-DX in the blood was slowed by the prior administration of dextran, meaning that the intake of TEMPO-DX into the liver from the blood was suppressed by the dextran.

Animals↗
PubMed1997

Beta ray-induced scission of DNA in tritiated water and protection by a green tea percolate and (-)-epigallocatechin gallate.

The beta-ray induced scission of puC18 plasmid DNA from E. coli in tritiated water was examined in the presence or absence of a green tea percolate (TP) and the main constituent, (-)-epigallocatechin gallate (EGCg). An analysis of the ratio of the original closed-circular to the open-circular form of DNA, which was formed by the strand scission of DNA, revealed that TP and EGCg showed a protective effect on DNA scission depending on their concentrations. A new technique, named solid state spin trapping, was applied to examine this scavenging ability toward the hydroxyl (OH) radical generated in tritiated water. The result was kinetically analyzed to reveal that TP and EGCg showed the scavenging effect, suggesting that the protective effect on DNA scission was attributable to the scavenging effect on the OH radical.

Beta Particles↗
PubMed1997

Protection by trehalose of DNA from radiation damage.

The most serious damage to cells exposed to radiation is attributed mostly to effects on the structure of cellular DNA. We found that trehalose protects DNA from irradiation. In the presence of 10 mM trehalose, DNA can be protected from about 4 times higher doses of beta- and gamma-ray irradiation. The protective effect increases with the amount of the sugar. Other disaccharides, sucrose, and maltose had similar effects.

Beta Particles↗
PubMed1997

[Three cases of mediastinal neurogenic tumors originating from the intrathoracic vagal nerve].

Three cases of mediastinal neurogenic tumors originating from the intrathoracic vagal nerve is reported. Two of those is neurilemmomas. One tumor was located in the site to the branching point of the recurrence nerve. The tumor was enucleated. Postoperative hoarseness arose. Another tumor was located in the vagal nerve. The tumor was resected. One of those is neurofibromatosis in the vagus nerve with the axillary tumor. The tumors arose from the vagus nerve was resected. Careful follow-up are required in two patients.

Adult↗
PubMed1997

[Evaluation of left ventricular ejection fraction using an automated contour tracking method: comparison with equilibrium radionuclide angiography].

A recently developed contour tracking method provides automated edge detection of left ventricular endocardium without a region of interest. The accuracy of this automated contour tracking (ACT) method in the evaluation of left ventricular ejection fraction was assessed in 20 patients (16 males and 4 females, mean age 58 years) using both the ACT method and equilibrium radionuclide angiography. Ejection fractions measured by the ACT method correlated well with those measured by equilibrium radionuclide angiography (y = 0.8x + 11.9, r = 0.91, SEE = 4.0%, p < 0.01). The ACT method provides an accurate estimate of left ventricular ejection fraction.

Echocardiography↗
PubMed1997

Factors associated with survival exceeding 5 years after transcatheter arterial embolization for hepatocellular carcinoma.

During the period between April 1981 and March 1988, 232 consecutive patients underwent transcatheter arterial embolization (TAE) for hepatocellular carcinoma at the Department of Radiology, Wakayama Medical College. A > or = 5-year course calculated from the time of the initial TAE was able to be confirmed in 216 patients, who became the subjects of this study. Five-year survival rates were calculated by the direct method, while the clinical features existing at the time of the initial therapy and the clinical course of patients surviving > or = 5 years were studied. The 5-year survival rate was 6.0%. Comparison of the patients dying within 1 year and the patients surviving for > or = 5 years revealed differences in the severity of liver cirrhosis and the tumor type. The long-term survivors tended to have low serum alpha-fetoprotein values. The clinical picture of the patients surviving > or = 5 years after TAE was characterized by relatively mild liver cirrhosis (Child's class A or B), a serum alpha-fetoprotein value of < or = 1,500 ng/dL, relatively small nodular-type tumors with a maximum main tumor diameter of < or = 5.5 cm, a tumor-occupying rate of less than 20%, and absence of portal vein involvement by the tumor. There were patients in whom a relatively small number of TAE sessions was effective in controlling the tumor for a prolonged period, with the patients then dying of causes unrelated to the tumor, as well as patients in whom proliferation of the tumor was controlled by numerous applications of transcatheter therapy, resulting in > or = 5-year survival but with eventual death due to the tumor. Transcatheter arterial embolization makes a major contribution to achieving long-term survival of > or = 5 years in patients with hepatocellular carcinoma.

Adult↗
PubMed1997

Video thoracoscopic resection of neurogenic tumor in a superior-posterior mediastinum: three case reports.

Neurogenic tumors of the thorax can originate in any neurogenic structure within the chest. Surgical resection is considered the primary treatment of such tumors and usually is performed through a thoracotomy. Recently, using a new approach, we applied the technique of video thoracoscopic surgery to resection a posterior mediastinal tumor. In this paper, we report three patients with superior-posterior mediastinal neurogenic tumors in which the approach to the tumor is technically difficult. Cases 1 and 2 were a 26-year-old man and a 50-year-old asymptomatic man, respectively, and case 3 was a 45-year-old asymptomatic woman. The sizes of the three tumors were 3.0 x 2.5 x 1.8 cm (case 1), 6.0 x 4.0 x 2.0 cm (case 2), and 3.0 x 2.0 x 2.0 cm (case 3). In one case (case 2), minithoracotomy was added to video thoracoscopic surgery for adhesion to the spinal artery and intraspinal extension. A standard thoracotomy was avoided in all three cases. All patients had uncomplicated postoperative courses. Video thoracoscopic resection of a neurogenic tumor in the superior-posterior mediastinum may be a safe and useful approach with improved cosmetic results.

Adult↗
PubMed1996

The oxidative burst protects plants against pathogen attack: mechanism and role as an emergency signal for plant bio-defence--a review.

Various aspects, mechanisms and functions of the oxidative burst with generation of O2- superoxide anions in plant cells, which is stimulated by active defence-inducing agents such as fungal infection or elicitor treatment, were reviewed mainly on the basis of experimental evidence obtained in a system of Solanaceae plants and Phytophthora spp. The oxidative burst may be due to an O(2-)generating NADPH oxidase in the plasma membrane, which is activated with combinations of cytosolic proteins, Ca2+, calmodulin and protein kinase, following stimulation by elicitor molecules. The oxidative burst may play the role of an internal emergency signal for induction of the metabolic cascade for active defence.

Cells, Cultured↗
PubMed1996

Sonic hedgehog is expressed in epithelial cells during development of whisker, hair, and tooth.

Sonic hedgehog (Shh) is a vertebrate gene homologous to a Drosophila segment polarity gene, hedgehog, and functions as a secreted signaling molecule in limb pattern formation, differentiation of motor neurons, and sclerotome induction. We found that Shh is also expressed in epithelia of the developing whisker, hair, tooth, rugae, and thyroid primordium of mouse embryos. In whisker and hair development, Shh is expressed in epithelial cells before condensation of the underlying mesenchymal cells and then in the placode. The expression of Shh continues in the hair bulb surrounding the dermal papilla. Shh is also expressed in epithelial cells of the tooth bud, then localized to the enamel knot. The Shh expression continues in developing ameloblasts. These results suggest that SHH is an essential epithelial signaling molecule in epithelio-mesenchymal interactions for the terminal differentiation.

Animals↗
PubMed1996

Polarizing activity, Sonic hedgehog, and tooth development in embryonic and postnatal mouse.

Tooth development involves reciprocal epithelial-mesenchymal interactions, polarized growth, mesenchyme condensation, and complex morphogenetic events. Because these processes bear similarities to those occurring in the developing limb, we asked whether morphogenetic signals found in the limb also occur in the developing tooth. We grafted mouse embryo tooth germs to the anterior margin of host chick embryo wing buds and determined whether the dental tissues had polarizing activity. Indeed, the grafts induced supernumerary digits. Activity of both molar and incisor tooth germs increased from bud to cap stages and was maximal at late bell stage in newborn. With further development the polarizing activity began to decrease, became undetectable in adult molar mesenchyme but persisted in incisor mesenchyme, correlating with the fact that incisors grow throughout postnatal life while molars do not. When different portions of neonatal incisors were assayed, a clear proximo-distal gradient of activity was apparent, with maximal activity restricted to the most proximal portion where undifferentiated mesenchyme and enamel organ reside. In situ hybridizations demonstrated that prior to induction of supernumerary digits, the tooth germ grafts induced expression in host tissue of Hoxd-12 and Hoxd-13. In addition, whole-mount in situ hybridizations and immunohistochemistry showed that developing tooth germs express Sonic hedgehog (Shh). Shh expression was first detected in bud stage tooth germs; at later stages Shh transcripts were prominent in enamel knot and differentiating ameloblasts at the cuspal region. We concluded that tooth germs possess polarizing activity and produce polarizing factors such as Shh. As in the limb, these factor(s) and activity probably play key roles in establishing polarity and regulating morphogenesis during early tooth development. Given its subsequent association with differentiating ameloblasts, Shh probably participates also in cytogenetic events during odontogenesis.

Aging↗
PubMed1996

Differential expressions of collagen types IV, III, and I during the development of invasive trophoblasts in rats.

We examined the differential expressions of collagen types IV, III and I in the developing feto-maternal placental tissue of pregnant rats by a combination of in situ hybridization and immunohistochemistry. At day 9.5 of gestation, polygonal invasive cytotrophoblasts from the ectoplacental cone, which was modifying the maternal central artery, revealed intensely expressed alpha 1 (IV) and alpha 1 (III) collagen mRNAs. The localization patterns of these translated products, collagen type IV and procollagen type III, were slightly different in the invasive cytotrophoblasts. Collagen type IV densely deposited intracellularly and intercellularly in the maternal central artery and in the thickened basement membranes of the cytotrophoblasts. However, expression of alpha 1 (I) collagen mRnA and procollagen type I was hardly detectable in the cytotrophoblasts. At day 13 of gestation, a high level of alpha 1 (IV) collagen mRNA was expressed in the cytotrophoblastic cell layer (trophospongium) and in the invasive large cytotrophoblasts. A moderate level of alpha 1 (III) collagen mRNA was also expressed mainly in the cytotrophoblasts, while alpha 1 (I) collagen mRNA was expressed at very low levels. Interestingly, procollagen type III failed to show linear immunoreactivity in the subepithelial extracellular matrix beneath the maternal artery with the invasive cytotrophoblasts. Additional quantitative analyses of these type IV, III, and I collagen mRNA levels in in situ hybridization experiments between several cell types also revealed significant differences individually. Electron-microscopic study detected no cross-striated collagen fibers in the thickened basement membrane-like structures adjacent to the invasive cytotrophoblasts. Fibrillar and basement membrane collagen gene expressions, their protein syntheses, and the processing of these procollagens seems to be developmentally regulated in the invasive cytotrophoblasts during the organization of feto-maternal placental tissue. The remodeling of the maternal central artery by the invasive cytotrophoblasts is important for ensuring the adequate blood supply to the developing placenta and fetus.

Animals↗
PubMed1996

Relationships between fiber composition and NMR measurements in human skeletal muscle.

The purpose of this study was to examine the relationships between the relative contents of phosphocreatine (PCr), inorganic phosphate (Pi), beta-adenosine triphosphate (ATP), and transverse relaxation time (T2) with fiber composition, which determined histochemically in the human skeletal muscle. The vastus lateralis muscles of 28 volunteers were subjected to phosphorus nuclear magnetic resonance (31P NMR) spectroscopy, magnetic resonance imaging (MRI) and muscle biopsy. Muscle fibers were divided into type I and type II fibers using myosin ATPase stain. A wide range of fiber composition levels were observed in the subjects (27.3-74.6% type I fibers). The PCr/ATP, Pi/ATP and (PCr + Pi)/ATP ratios were positively related to the percentage of type II fibers (r = 0.695, p < 0.001, r = 0.429, p < 0.05 and r = 0.773, p < 0.001, respectively). There was no correlation between fiber composition and the PCr/Pi ratio (r 0.127, n.s.) or intracellular pH (r = 0.305, n.s.). Moreover, no correlation was found between T2 and fiber type (r = 0.144, n.s.). These results suggest that 31P NMR can detect the differences in relative content of phosphates between type I and type II fibers, thereby noninvasively evaluating fiber composition in human skeletal muscle.

Adenosine Triphosphate↗
PubMed1996

Establishment of bone morphogenetic protein 2 responsive chondrogenic cell line.

A clonal cell line named RMD-1 was established from the skeletal muscle of a 20-day fetal rat. RMD-1 represents a morphologically homogeneous population of undifferentiated mesenchymal cells, expressing alpha-smooth muscle actin and type I collagen, but no cartilage-associated genes. When cultured in agarose gel containing 100 ng/ml of recombinant human bone morphogenetic protein 2 (rhBMP-2; BMP-2), RMD-1 cells formed colonies and showed chondrocyte-like features as assessed by their ultrastructure, metachromatic staining with toluidine blue, and the production of large hydrodynamic-size proteoglycans. RMD-1 cells also differentiated into chondrocytes when the cells were plated at high density (over 2.5 x 10(5) cells/cm2) on type I collagen and incubated in medium containing 0.5% fetal bovine serum and 100 ng/ml of BMP-2. This chondrogenic differentiation was evidenced by a distinct morphological change into spherical cells, an increase in the levels of sulfated glycosaminoglycans, a decrease in type I collagen mRNA and the expression of cartilage-associated genes, including type II collagen, type IX collagen, aggrecan and alkaline phosphatase. In the presence of ascorbic acid and 10% serum, RMD-1 cells increased in size and expressed type X collagen as well as high alkaline phosphatase activity, then induced matrix mineralization. Thus, RMD-1 is a unique cell line that can differentiate from undifferentiated mesenchymal cells into hypertrophic chondrocytes.

Actins↗
PubMed1996

Dynamic electron spin resonance (ESR) imaging of the distribution of spin labeled dextran in a mouse.

The nitroxide group 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) was covalently bound to a dextran via an N-acetamido linkage to produce a novel spin probe, TEMPO-dextran (TEMPO-DX), which circulates for long time periods in an animal without metabolic degradation. TEMPO-DX was stable in mice, while small TEMPO analogs quickly disappeared after administration. Since dextran was reduced somewhat in size during synthesis, the resultant spin-labeled dextran could be excreted through the kidney. A strong L-band electron spin resonance signal was obtained shortly after intravenous administration of TEMPO-DX into the tail vein of a mouse, from which three-dimensional images of specific organs were calculated. The signal was found to persist for well over 1 h.

Animals↗
PubMed1996

Urinary incontinence in elderly inpatients in Japan: a comparison between general and geriatric hospitals.

This is the first multi-hospital epidemiological study to elucidate the prevalence and characteristics of urinary incontinence in elderly inpatients throughout Japan. Of the 2586 subjects to whom questionnaires were issued, 1563 (60.4%) (65 to 102 years old, 598 men, 965 women) were suitable for the study. A total of 817 patients were hospitalized in geriatric hospitals; that is, geriatric facilities under the regulation of the Department of Health and Welfare. All patients were evaluated by medical doctors for the following items: age, sex, duration of hospitalization, activities of daily living, medical diagnosis, presence or absence of urinary incontinence, type of urinary incontinence, and therapy for urinary incontinence. The prevalence of urinary incontinence in patients under 70, 70-79, 80-89, and over 90 years old was 59.3%, 67.7%, 79.8%, and 82.2%, respectively. Overall, 1142 patients (72.0%) suffered from urinary incontinence. Cerebrovascular disease was the major cause of admission to hospital in patients with urinary incontinence (37.0%). The most frequent type of urinary incontinence was functional urinary incontinence in patients who were mentally and/or physically unable to go to the bathroom without aid (21.5%). Specifically, 38.1% of patients in geriatric hospitals were diagnosed as having functional urinary incontinence, in contrast to only 3.9% of patients in non-geriatric units. In patients with dementia, 88.7% were incontinent, whereas in patients without dementia, the prevalence of urinary incontinence was much lower (51.5%, p < 0.001). Another predisposing factor for urinary incontinence was urinary tract infection. The prevalence of urinary incontinence in patients with and without urinary tract infection was 87.8% and 59.5%, respectively (p < 0.001). Almost all patients with poor activities of daily living (who were bedridden) suffered from urinary incontinence (98.5%). On the other hand, urinary incontinence was not so frequent in patients who could walk (26.9%). Pad (42.8%) and indwelling bladder catheter (18.3%) were the major means of management of incontinence, whereas behavioral therapy (4.9%) and surgery (0.5%) were not common. These results suggest that elderly patients with treatable urinary incontinence do not receive adequate therapy in Japan.

Activities of Daily Living↗
PubMed1996

Spinal cord MRI in neuro-Behçet's disease.

We report the case of a 10-year-old boy with neuro-Behçet's disease. Spinal cord MRI showed signal abnormalities in the cervical and thoracic cord, but cerebral CT and MRI revealed no abnormality.

Behcet Syndrome↗