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Biomedical subjects

S Onishi

Publications and source records attributed to S Onishi.

At least 55 records · Page 3Linked to original sources
PubMed2000

Transforming growth factor-beta 1 derived from biliary epithelial cells may attenuate alloantigen-specific immune responses.

Immune response to liver allografts may be different from that to other organ transplants since immunological manipulation easily attenuates immune-response to liver allografts. Numerous studies on the alloantigen-specific immune response have been carried out, however, the precise mechanisms involved in this attenuation are not clear yet. Here we suggest the attenuation of alloantigen-specific immune response by TGF-beta 1 derived from biliary epithelial cells. The transforming growth factor-beta 1 (TGF-beta 1) expression in rat liver was examined immunohistologically. Rat biliary epithelial cells (BEC) were purified from the perfused liver and added to allogeneic mixed lymphocyte reaction (allo-MLR) to assess their attenuating potential on allo-MLR and alloantigen-specific cytotoxic T lymphocyte (allo-CTL) induction. Immunohistological investigation revealed the expression of TGF-beta 1 in biliary epithelial cells. Both purified biliary epithelial cells and TGF-beta 1 attenuated allo-MLR and allo-CTL induction in a dose-dependent manner, and anti-TGF-beta 1 antibody partially relieved this attenuation. This study reveals that biliary epithelial cells, the major target cells of allo-antigen specific immune response, contain TGF-beta 1 and that they have a capacity to attenuate allo-MLR and allo-CTL induction.

Animals↗
PubMed2000

Expression of UDP-GalNAc: polypeptide N-acetylgalactosaminyltransferase isozymes T1 and T2 in human colorectal cancer.

Uridine diphosphate (UDP)-GalNAc: polypeptide N-acetylgalactosaminyltransferase (GalNAc transferase) catalyzes the initial step in mucin type O-glycosylation, and its expression has been assumed to be altered between normal epithelial cells and cancer cells. We studied the alteration of GalNAc transferase expression during the carcinogenesis of human colorectal epithelial cells. We produced polyclonal antibodies against synthetic polypeptides with specific sequence to two GalNAc transferase isozymes, T1 and T2. Surgically resected specimens from 50 patients with colorectal cancer were immunohistochemically stained, and the staining grade (percentage of positively stained cells) was compared between cancer and its normal counterpart in the same specimen. Significant signals for both T1 and T2 expression were seen in the supranuclear region of normal and cancer cells, indicating the subcellular localization of the enzymes in the Golgi apparatus. The prevalence of positive staining for T1 and T2 expression in colorectal cancer was significantly higher than that in normal epithelium (P < 0.05). However, the difference in staining grades between cancer and normal tissues varied in each patient. These results indicate that there is variability in the expression patterns of GalNAc transferase isozymes in normal and cancerous cells colorectal among individuals.

Adenocarcinoma↗
PubMed2000

Aortic root dilatation among young competitive athletes: echocardiographic screening of 1929 athletes between 15 and 34 years of age.

BACKGROUND: Aortic dilatation can be lethal for young competitive athletes. The prevalence among athletes is not known, however, and thus a reasonable approach to early recognition remains uncertain. METHODS AND RESULTS: Echocardiograms of 1929 normotensive athletes 15 to 34 years of age were analyzed. Five (0.26%) athletes had aortic dilatation; 4 of the 5 played basketball. This made the prevalence of aortic dilatation 0.96% (4 of 415) among basketball and volleyball players, who represented a population of especially tall athletes. Tallness aside, only 2 of the 5 athletes had features of Marfan syndrome. Among the athletes without aortic dilatation, the relation between body surface area and aortic root dimension was nonlinear and best described with a quadratic regression model. Athletes with aortic dilatation fell well outside the 95% confidence interval. CONCLUSION: Because a higher incidence of aortic dilatation is to be anticipated among very tall athletes, inclusion of echocardiography in screening before participation in certain sports should be considered.

Adolescent↗
PubMed2000

Developmental changes of vitamin K epoxidase and reductase activities involved in the vitamin K cycle in human liver.

We examined the developmental changes in activities of vitamin K epoxidase, and vitamin K-2,3-epoxide reductase and vitamin K reductase in the human autopsied liver. The activity of epoxidase, which converts vitamin K hydroquinone to its epoxide, showed a high value in the early prenatal period of 10-30 gestational weeks but decreased rather rapidly in contrast with the reductase activities. After birth, a significant decrease of the epoxidase activity was observed but no such change was seen during the postnatal period. On the other hand, the activities of vitamin K-2,3-epoxide reductase and vitamin K reductase, which convert vitamin K-2,3-epoxide to its hydroquinone, showed a significantly low value in the early prenatal period. The highest activity of vitamin K epoxidase in the early prenatal period may be essential to the production of vitamin K dependent ligands for growth factors expressed in the embryo.

Adolescent↗
PubMed2000

Hepatic taurine, glycine and individual bile acids in early human fetus.

OBJECTIVE: To examine 3alpha-hydroxy individual bile acid and the association between taurine and taurine-conjugated bile acid in human fetal liver. METHODS: Taurine, glycine and the individual bile acids in liver samples taken from 17 human fetuses whose abortion was induced from 12 to 23 weeks' gestation were determined by high-performance liquid chromatography. RESULTS: The concentrations of taurine, glycine and bile acids in early fetal life were not related to gestational age. Hepatic taurine was statistically correlated with total taurine-conjugates (r = 0.798; P < 0.0001), but hepatic glycine was not correlated with glycine-conjugates (r = -0.103; P > 0.05). Lithocholic acid was conjugated exclusively with taurine. CONCLUSIONS: Our results supported that in human fetal life there is a considerable bile acid pool in liver, and that taurine works effectively on the bile acid metabolism depending on the hepatic taurine concentration.

Abortion, Induced↗
PubMed2000

Formation of propentdyopents and biliverdin, oxidized metabolites of bilirubin, in infants receiving oxygen therapy.

BACKGROUND: Bilirubin has antioxidative effects. When bilirubin reacts with reactive oxygen species, oxidized metabolites of bilirubin are formed, such as biliverdin and propentdyopents. A decrease in serum bilirubin concentration and an increase in serum and urinary oxidized metabolites of bilirubin may indicate the protective action of bilirubin against reactive oxygen species. METHODS: In the in vitro study, we measured the oxidative products of bilirubin formed through the action of O2- by the xanthine-xanthine oxidase system, either as free bilirubin or bilirubin-human serum albumin complex. In the clinical investigation, serum concentrations of (ZZ)-bilirubin (4Z, 15Z-bilirubin), the subfraction and biliverdin, and urinary propentdyopent absorption, were measured in blood and urine samples, respectively, collected from 30 5-day-old neonates with birth weights of 1500-3624 g who had been hospitalized at the Ehime Prefectural Hospital and who had not undergone phototherapy. RESULTS: In the in vitro study, a significant formation of propentdyopents was observed in aqueous solution. A statistically significant correlation was found between serum (ZZ)-bilirubin concentration and serum biliverdin concentration (r = 0.82, P < 0.0001), but not between serum (ZZ)-bilirubin concentration and urinary propentdyopent absorption. Serum (ZZ)- and serum (ZE)-bilirubin and biliverdin concentrations, and urinary propentdyopent absorption were compared between the groups with and without oxygen therapy. No significant differences were found in serum (ZZ)-bilirubin, serum (ZE)-bilirubin and biliverdin concentration, urinary propentdyopent absorption, serum biliverdin/serum (ZZ)-bilirubin, or urinary propentdyopent absorption/serum (ZZ)-bilirubin. Neither a decrease in serum bilirubin concentration nor an increase in serum biliverdin concentration and urinary propentdyopent absorption after oxygen therapy were demonstrated in the present study. CONCLUSIONS: In the in vitro study, we demonstrated for the first time that propentdyopents were produced from (ZZ)-bilirubin by the xanthine-xanthine oxidase system but biliverdin was not. In the in vivo study, serum biliverdin concentration and urinary propentdyopent absorption seem to have a different relationship to serum (ZZ)-bilirubin concentration in sick and early neonates.

Bilirubin↗
PubMed2000

The role of anti-epithelial cell antibodies in the pathogenesis of bilateral radiation pneumonitis caused by unilateral thoracic irradiation.

Two cases of bilateral radiation pneumonitis associated with unilateral thoracic irradiation against lung cancer are described. Both patients died of respiratory failure and autopsy was performed. Histologically, bilateral diffuse alveolar damage was demonstrated in both cases, associated with marked organization of hyaline membrane in one case (case 1). In addition, numerous hyperplastic type II pneumocytes which strongly expressed cytokeratins 8, 18 and 19 were observed. In both patients' sera, antibodies against cytokeratin 8, 18 and 19 were demonstrated by a Western immunoblot. The possible association between autoantibodies to cytokeratins and diffuse alveolar damage observed in patients with bilateral radiation pneumonitis are discussed.

Adenocarcinoma↗
PubMed2000

Physiological profile of middle-aged and older climbers who ascended Gasherbrum II, an 8035-m Himalayan peak.

BACKGROUND: The purpose of this study was to investigate the physiological characteristics of a group of middle-aged and older Japanese climbers who ascended Gasherbrum II, an 8035-m peak in the Karakoram Range of the Himalayas. METHODS: Body composition, cardiac structure, and respiratory gas exchange during exercise were estimated in eight climbers with differing levels of experience (seven men and one woman, aged 54 to 63 years) 6 months before their expedition. RESULTS: Using supplementary O2, the four experienced climbers ascended beyond Camp 4 (7400 m) without showing any health problems and were able to attempt the summit. In contrast, the others, who had minimal experience at extreme altitude, suffered from altitude sickness on the way to Camp 4. Body mass index values were relatively high, but their low percentage of body fat (14.9%-21.4%) was indicative of the climbers' substantial lean body weight. Cardiac structures were generally normal, although three experienced male climbers had borderline hypertension and eccentric hypertrophy of the left ventricle. Peak VO2 ranged from 30.9 to 45.6 ml/kg/min, and no significant relationship between fitness level and the success or failure of the ascent was evident. CONCLUSIONS: Even sexagenarians are capable of safely climbing 8000-m peaks with supplementary O2. An exceptionally high fitness level, as is seen in elite older athletes, does not appear to be required. What is essential, however, is moderate fitness, good health, and extensive experience.

Aged↗
PubMed2000

Peak aerobic performance and left ventricular morphological characteristics in university students.

OBJECTIVE: To determine whether a relationship exists between left ventricular morphology and aerobic capacity in large numbers of male university students with a physically inactive and active life style. DESIGN: A prospective study. SETTING: Sports medicine research center. PARTICIPANTS: Eleven sedentary normal-weight university students, 17 sedentary overweight university students, and 215 university athletes. MAIN OUTCOME MEASURES: After the echocardiographic examination, an incremental treadmill exercise test until exhaustion was performed to measure peak oxygen uptake (VO2). RESULTS: In sedentary students, absolute peak VO2 in the overweight students was slightly higher than that in normal-weight students (3,024 vs. 2.912 ml/min). Relative peak VO2 (ml/min/kg) was highly negatively correlated with body mass index (kg/m2) in a total of 28 sedentary students. The correlation between absolute peak VO2 and left ventricular dimension was weak in the sedentary overweight students; however, a correlation coefficient of 0.55 was obtained in athletic students. A stepwise multiple regression showed significant determinants of absolute peak VO2 in athletic students for body surface area (45%), left ventricular dimension (7%), and certain sports (6%). CONCLUSIONS: A physically active life style plays a role in increasing both aerobic capacity and left ventricular enlargement. Body size appeared to be a potent stimulus to left ventricular enlargement.

Adult↗
PubMed2000

Changes in cerebral hemoglobin concentration and oxygen saturation immediately after birth in the human neonate using full-spectrum near infrared spectroscopy.

Using full-spectrum near infrared spectroscopy (fsNIRS), we measured changes in oxy- and deoxyhemoglobin (HbO2 and Hb), total hemoglobin (T-Hb) concentration, and hemoglobin oxygen saturation (SbO2) in the brain tissue of seven neonates immediately following birth. It was found that HbO2 rose rapidly within 2-3 min after birth. During the same time, there was a transient increase in T-Hb concentration, after which it decreased together with Hb. SbO2 increased rapidly after birth, from 18% at 1.5 min to about 55% at 5-6 min, followed by a gradual increase of about 10%. Oxygenation in the brain occurred much sooner in three subjects given oxygen for a short time immediately after birth than in those who did not receive oxygen. This preliminary study indicated that dynamic changes occur in cerebral circulation and oxygenation as part of the physiological changes taking place soon after birth.

Brain↗
PubMed2000

Altered expression of fatty acid-metabolizing enzymes in aromatase-deficient mice.

Hepatic steatosis is a frequent complication in nonobese patients with breast cancer treated with tamoxifen, a potent antagonist of estrogen. In addition, hepatic steatosis became evident spontaneously in the aromatase-deficient (ArKO) mouse, which lacks intrinsic estrogen production. These clinical and laboratory observations suggest that estrogen helps to maintain constitutive lipid metabolism. To clarify this hypothesis, we characterized the expression and activity in ArKO mouse liver of enzymes involved in peroxisomal and mitochondrial fatty acid beta-oxidation. Northern analysis showed reduced expression of mRNAs for very long fatty acyl-CoA synthetase, peroxisomal fatty acyl-CoA oxidase, and medium-chain acyl-CoA dehydrogenase, enzymes required in fatty acid beta-oxidation. In vitro assays of fatty acid beta-oxidation activity using very long (C24:0), long (C16:0), or medium (C12:0) chain fatty acids as the substrates confirmed that the corresponding activities are also diminished. Impaired gene expression and enzyme activities of fatty acid beta-oxidation were restored to the wild-type levels, and hepatic steatosis was substantially diminished in animals treated with 17beta-estradiol. Wild-type and ArKO mice showed no difference in the binding activities of the hepatic nuclear extracts to a peroxisome proliferator response element. These findings demonstrate the pivotal role of estrogen in supporting constitutive hepatic expression of genes involved in lipid beta-oxidation and in maintaining hepatic lipid homeostasis.

Acyl-CoA Dehydrogenase↗
PubMed2000

Effects of bilirubin and its photoisomers on direct bilirubin measurement using bilirubin oxidase.

We examined the reactivity of human serum albumin-bound bilirubin and its photoisomers as substrates for a direct bilirubin assay using bilirubin oxidase. The reduction of (EZ)-cyclobilirubin reached 100% 5 min after addition of the enzyme at any pH tested (3.5-7.4) in 0.1 mol/L phosphate buffer, whereas the reduction of (ZE)-bilirubin or (ZZ)-bilirubin reached 100% only below pH 4.5 or 5.5, respectively. (ZZ)-Bilirubin and its photoisomers did not react in citrate-lactate buffer at pH 3.7. The circular dichroism spectrum of (ZZ)-bilirubin in this buffer did not show a positive Cotton effect. These results indicate that a three-dimensional structure surrounding the reaction site of bilirubin is important for the reactivity with bilirubin oxidase.

Bilirubin↗