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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 415 records · Page 23Linked to original sources
PubMed1995

Synthesis of (1-->4)-beta-D-xylo-oligosaccharides of dp 4-10 by a blockwise approach.

Dibutyltin oxide-mediated regioselective chloroacetylation of methyl 1-thio-beta-xylobioside, followed by treatment of the product with 4-methylbenzoyl chloride-pyridine, gave methyl 4-O-chloroacetyl-2,3-di-O-(4-methylbenzoyl)-beta-D-xylopyranosyl-(1-->4) -2.3-di - O-(4-methylbenzoyl)-1-thio-beta-D-xylopyranoside (18) in 70% yield. Coupling of 18 with benzyl alcohol afforded the disaccharide benzyl beta-glycoside, which was O-dechloroacetylated to provide methyl 2,3-di-O-(4-methylbenzoyl)-beta-D-xylopyranosyl-(1-->4)-2,3-di-O-(4- methylbenzoyl)-1-thio-beta-D-xylopyranoside (20). A homologous series of (1-->4)-beta-D-xylo-oligosaccharides from the tetra- to the deca-saccharide have been synthesized in a blockwise manner by using 20 as the glycosyl acceptor, 18, methyl 1-thio-beta-xylobioside pentaacetate, and methyl 1-thio-beta-xylotrioside heptaacetate as the glycosyl donors, and a combination of N-iodosuccinimide-silver triflate as the promoter.

Carbohydrate Conformation↗
PubMed1995

Synthesis of 2- and 4-nitrophenyl beta-glycosides of beta-(1-->4)- D-xylo-oligosaccharides of dp 2-4.

2- and 4-Nitrophenyl beta-D-xylopyranosides (4 and 5) were transformed, via dibutyltin oxidemediated acylation, into the corresponding 2,3-di-O-benzoyl derivatives 11 and 15. Xylobiose and xylotriose were easily isolated by charcoal column chromatography from a commercially available material and converted into the di- and trisaccharide methyl 1-thio-beta-glycosides 36 and 37. The 2-and 4-nitrophenyl beta-glycosides of the beta-(1-->4)-D-xylo-oligosaccharides of dp 2-4 were synthesized by N-iodosuccinimide-silver triflate-promoted condensation using 11 and 15 as the glycosyl acceptors and ethyl 1-thio-beta-D-xylopyranoside triacetate 16, 36, and 37 as the glycosyl donors. Also described are an improved preparation of 4 and 5, and the synthesis of 1-naphthyl beta-D-xylopyranoside, as well as an alternative approach to the 2- and 4-nitrophenyl beta-xylobiosides.

Carbohydrate Sequence↗
PubMed1995

Helicobacter pylori increases gene expression of hepatocyte growth factor in human gastric mucosa.

Helicobacter pylori (H. pylori) induces hyperproliferation of the gastric mucosa. This study was designed to clarify whether H. pylori infection is involved in the gene expression of hepatocyte growth factor (HGF), a potent stimulator of cell proliferation in gastric mucosa. Levels of HGF mRNA were determined by a reverse transcription-polymerase chain reaction in endoscopic gastric biopsy specimens from 9 control subjects and 9 patients with H. pylori infection. In patients with H. pylori infection, levels of HGF mRNA in gastric mucosa were significantly higher than those in control subjects. HGF mRNA levels in patients with H. pylori infection were correlated with the severity of gastric mucosal inflammation. Our observations indicate that H. pylori infection increases the expression of HGF gene in gastric mucosa probably through the mucosal inflammation.

Adult↗
PubMed1995

Usefulness of interlocking detachable coil for embolization of the major aorto-pulmonary collateral artery: a case report.

A 5-yr-old male had undergone a right-modified Blalock-Taussig shunt operation at the age of 1 mo for stenotic patient ductus arteriosus and pulmonary atresia with ventricular septal defect. Before a corrective operation, the angiogram revealed one large major aorto-pulmonary collateral artery from the descending aorta to the right upper lung. Embolization of the major aorto-pulmonary collateral artery was successfully performed using interlocking detachable coils. This is the first reported case of embolization of the major aorto-pulmonary collateral artery using this device.

Angiography↗
PubMed1995

Salmon GnRH synthesis in the preoptic area and the ventral telencephalon is activated during gonadal maturation in female Masu Salmon.

Changes in salmon gonadotropin-releasing hormone (sGnRH) synthetic activity in the brain during gonadal maturation were examined by in situ hybridization in 2-year-old female masu salmon. Oncorhynchus masou. During gonadal maturation, the numbers of neurons expressing sGnRH mRNA increased in the preoptic area and the ventral telencephalon, but not in the olfactory bulbs and the terminal nerve ganglion. The numbers of silver grains per neuron also increased in the preoptic area and the ventral telencephalon. These results indicate that sGnRH has multiple physiological functions according to the location of the neurons in the brain; neurons in the preoptic area and the ventral telencephalon are involved in gonadal maturation possibly by stimulating gonadotropin synthesis and release, whereas neurons in the olfactory bulbs and the terminal nerve ganglion may have different roles.

Animals↗
PubMed1995

Short photoperiod accelerates preoptic and ventral telencephalic salmon GnRH synthesis and precocious maturation in underyearling male masu salmon.

The temporal relationship between testicular maturation and salmon gonadotropin-releasing hormone (sGnRH) mRNA expression was investigated in underyearling precocious male masu salmon, Oncorhynchus masou. Testicular maturation could be experimentally manipulated by changing the length of the light-dark photoperiod; maturation was accelerated in the short photoperiod group (8L-16D) and delayed in the long photoperiod group (16-8D). sGnRH mRNA and total silver grains in these loci in individual fish, increased with advancing testicular maturation. They were maximal in the short photoperiod group in August and in the long photoperiod group in September, when spermiation occurred. In contrast, marked changes in sGnRH synthetic activity in relation to testicular maturation were not observed in the terminal nerve ganglion or in the olfactory bulbs. sGnRH neurons in the preoptic area and the ventral telencephalon are clearly influenced by photoperiod and are involved in the control of gonadal maturation probably via gonadotropin secretion.

Animals↗
PubMed1995

Flow cytometric analysis of the DNA content of thymomas.

In this study, the prognostic value of determining the nuclear DNA content of thymomas by flow cytometry was evaluated. Of a total 31 resected thymomas, 10 (32%) showed DNA aneuploidy, the presence of which was significantly correlated with an advanced clinical stage of disease. The patients with an aneuploid tumor had a poorer prognosis than those with a diploid tumor, demonstrating a survival rate of 50% at 7 postoperative years, which was considerably less favorable than that of the patients with a diploid tumor, being 100% in the same period (p < 0.05). Moreover, patients with a high DNA index (DI), i.e., a DI >or= 1.5, tended to have a poorer prognosis than those with a low DI. These findings indicated that the DNA content can be an important prognostic index in patients with thymomas.

Adult↗
PubMed1995

Left atrial plication combined with mitral valve surgery in patients with a giant left atrium.

The benefits of performing left atrial plication during mitral valve surgery for patients with a giant left atrium were evaluated by analyzing the short- and long-term surgical results and changes in the left atrial dimension (LAD) and respiratory function of 30 patients. Of the 30 patients, 2 (7%) died of multiple organ failure on postoperative days 26 and 117, but no other deaths occurred during the mean follow-up of 5.9 +/- 2.1 years. Valve thrombosis was observed in one patient and cerebral complications with no residual deficit were observed in two patients, with a 9-year event-free rate of 87 +/- 7%. The LAD decreased significantly from 69.0 +/- 8.5 mm to 53.7 +/- 9.1 mm (P < 0.01) shortly after surgery, and this decreased was maintained even 5 years after surgery (53.3 +/- 11.4 mm). The cardiothoracic ratio decreased from 74.8 +/- 8.3% to 62.8 +/- 9.0% (P < 0.01) and the vital capacity of the lungs increased from 71.1 +/- 18.0% to 82.9 +/- 22.2% (P < 0.01). Thus, we conclude that performing left atrial plication during mitral valve surgery is safe and effective for patients with giant left atrium.

Adult↗
PubMed1995

Usefulness of femoro(ilio)-axillar bypass surgery for the treatment of subclavian steal syndrome caused by aortitis syndrome.

In two patients with subclavian steal syndrome associated with aortitis syndrome, retrograde bypass grafting from the femoral or common iliac artery to the axillary artery resulted in the disappearance of symptoms. One patient, a 37-year-old female, was treated with a bypass from the left femoral artery to the left axillary artery with a 10-mm ring-supported double velour knitted Dacron graft. The other patient, a 54-year-old female, with the complication of moderate aortic regurgitation, was treated with a bypass from the left common iliac artery to the left axillary artery with an 8-mm EPTFE graft. These bypass grafts were angiographically confirmed to be patent after the operation. When changes in graft flow in different body positions (supine, sitting, and standing) were examined, using a transcutaneous Doppler flow meter, 5 years after the operation, resting graft flow to the upper extremities showed no consistent changes among the three different positions and was maintained in a stable condition, regardless of the patients' positions. Furthermore, graft flow increased while the left arm exercised. This finding, together with the clinical efficacy, indicates that this mode of retrograde bypass grafting may be effective in some selected patients with this complicated syndrome.

Adult↗
PubMed1995

Systolic and diastolic function after patch reconstruction of left ventricular aneurysms.

Left ventricular function after patch reconstruction for postinfarction left ventricular aneurysms is largely unknown. In this study, 16 patients with an anteroseptal-lateral left ventricular aneurysm were treated by reconstruction of the left ventricle using a Dacron patch. Coronary artery bypass grafting was performed concomitantly in 9 patients. The size of the patch used was 57% +/- 19% of the resected myocardial scar area, including the sewing cuff area to be sutured. In these patients, the ejection fraction increased significantly from 0.28 +/- 0.12 to 0.39 +/- 0.12 (p = 0.007) at rest and from 0.32 +/- 0.14 to 0.41 +/- 0.10 (p = 0.008) during exercise. The left ventricular end-diastolic pressure and left ventricular end-diastolic volume index were reduced significantly from 14 +/- 7.0 to 8 +/- 3.2 mm Hg (p = 0.032), and from 178 +/- 116 to 92 +/- 21 mL/m2 (p = 0.016). The peak filling rate was improved significantly from 1.2 +/- 0.47 to 1.8 +/- 0.6/s (p = 0.048) postoperatively. The ratio of the peak flow velocity during the atrial kick phase to the peak flow velocity in the rapid filling phase, at the level of the mitral valve, improved (p = 0.016) after operation and remained improved up to 16 to 24 months after operation. Patch reconstruction of the left ventricle resulted in the recovery of systolic and diastolic function soon after operation, which has persisted into the late postoperative period.

Blood Pressure↗
PubMed1995

Effect of warm ischemia and cryopreservation on cell viability of human allograft valves.

Fibroblast viability of the allograft valve leaflet has been suggested to affect clinical durability. Warm ischemic time is thought to be one of the critical determinants of cell viability. We assessed cell viability of allograft valves by flow cytometry, using a fluorescein diacetate-propidium iodide stain to characterize the effects of warm ischemia and cryopreservation on viability. Twelve human pulmonary valves with harvest-related warm ischemic times (range, 70 to 520 minutes; mean +/- standard deviation, 225 +/- 157 minutes) were studied by flow cytometry. We assessed cell viability of the allograft valve leaflets before and 30 days after storage. A significant negative correlation was found between warm ischemic time (x minutes) and cell viability (y%) before (y = -0.024x + 96.7; r2 = 0.62; p = 0.002) and after 30 days of storage (y = -0.036x + 94.0; r2 = 0.86; p = 0.001). Cell viability of the cryopreserved allograft valves was well preserved (> 70%) with a warm ischemic time less than 520 minutes (8.7 hours).

Adult↗
PubMed1995

Identification of osteopontin in human dental calculus matrix.

Osteopontin is a prominent non-collagenous component of bone matrix, although it is expressed in several other tissues. Recently, osteopontin was reported to be involved in urinary stone formation and atherosclerotic lesions of the aorta, suggesting that it may be a key protein associated with these types of pathological mineralization. In this study, whether or not human dental calculus contains osteopontin was investigated by immunoblotting and immunohistochemical analyses. After extraction of calculus proteins with EDTA and separation of the proteins by electrophoresis, immunoblotting analysis revealed the presence of osteopontin. Two forms of osteopontin appeared at 61 and 68 kDa on 10% polyacrylamide gel and the proteins were digested with thrombin, a highly specific protease. Moreover, immunohistochemical analysis revealed that osteopontin was localized in dental calculus adherent to tooth roots. These findings indicate that osteopontin is, in fact, present in human dental calculus and may be involved in calculus formation as the stone matrix.

Dental Calculus↗
PubMed1995

Liver with hypoechoic nodular pattern as a risk factor for hepatocellular carcinoma.

BACKGROUND/AIMS: Ultrasonography should be used for screening of hepatocellular carcinoma, but there are few reports on the relationship between liver ultrasonographic findings and the development of hepatocellular carcinoma (HCC). Using prospective follow-up studies, we examined the role of liver with a hypoechoic nodular pattern as a high-risk factor in HCC. METHODS: The study was performed by follow-up on 593 patients with chronic liver disease recorded at our hospital. The ultrasonographic pattern of the liver parenchyma was classified either as a small or large hypoechoic nodular pattern or as a nonnodular pattern. Patients were followed up from the time of initial ultrasonographic examination (1985-1987) until January 1, 1991. RESULTS: During the follow-up period (average, 4.2 years, range, 0.3-6.0 years), 62 patients were found to have HCC (12%). Patients whose livers showed small or large hypoechoic nodular pattern had a significantly higher risk of HCC than did patients whose livers showed a nonnodular pattern (rate ratios were 14.0 and 20.0, respectively, adjusted for age, sex, hepatitis virus markers, ICG R15, alpha-fetoprotein concentration, and ultrasonographic pattern of the liver). CONCLUSIONS: Liver showing a hypoechoic nodular pattern is a major risk factor in HCC.

Adult↗
PubMed1995

Soluble CD14 in serum mediates LPS-induced increase in permeability of bovine pulmonary arterial endothelial cell monolayers in vitro.

Lipopolysaccharide (LPS) is a mediator of septic shock and acute respiratory distress syndrome (ARDS), conditions which are characterized by high-permeability pulmonary edema. LPS increases endothelial permeability both directly and indirectly via the pro-inflammatory cytokines produced by monocytes and macrophages. We investigated the role of soluble CD14 in serum in the increased endothelial permeability induced by LPS. Bovine pulmonary artery endothelial cells were grown to confluence on a microporous filter and the 125I-albumin clearance rate across the monolayer was determined. Even a high concentration of LPS (1 microgram/ml) did not increase endothelial permeability under a serum-free condition. In the presence of more than 3% normal human serum, LPS increased endothelial permeability. The presence of neutralizing anti-CD14 monoclonal antibody eliminated the serum-dependent effect of LPS. The addition of recombinant sCD14 completely replaced the requirement for serum. LPS-binding protein (LBP) did not enhance the rsCD14-mediated LPS effect, and anti-LBP antibody did not attenuate the serum-dependent LPS effect. These findings suggest that sCD14 in serum mediates the permeability-increasing effect on LPS on endothelial cells but that LBP is not necessary for this effect.

Acute-Phase Proteins↗
PubMed1995

Eicosapentaenoic acid modulates arachidonic acid metabolism in rat alveolar macrophages.

Eicosapentaenoic acid (EPA) is an unsaturated fatty acid contained in fish oils. In order to clarify the mechanism of its anti-inflammatory effects on the lung, we studied arachidonic acid (AA) metabolism by in vitro exposure of rat alveolar macrophages to EPA. EPA was found to inhibit the endogenous production of leukotriene B4 (LTB4) from AA. At a low concentration of EPA, generation of LTB5 was increased, while at a high concentration it was decreased. These results suggest that at a lower concentration EPA may be competitive with AA as a substrate, and that at a higher concentration it may directly inhibit AA metabolism via inhibition of 5-lipoxygenase or phospholipase A2.

Animals↗
PubMed1995

Effectiveness of galactose-based intravenous contrast medium on color Doppler sonography of deeply located hepatocellular carcinoma.

The purpose of this study is to examine the effectiveness of intravenously injectable sonographic contrast medium for color Doppler sonographic diagnosis of deeply located hepatocellular carcinoma. Subjects were 7 hepatocellular carcinomas, an adenomatous hyperplasia and a hemangioma located more than 7 cm below the abdominal surface. Levovist, a galactose-based sonographic contrast medium was injected through median cubital vein as a phase-two clinical study, and the pre- and post-enhanced color Doppler sonographic findings of these lesions were compared. The incidence of the positive findings for hepatocellular carcinoma increased from 29% (2/7) to 86% (6/7) of hepatocellular carcinoma after contrast enhancement. Positive findings were 0% in other cases even after enhancement. Levovist brought a certain improvement in the visualization of the tumor vessel by color Doppler sonography without any noteworthy side effects. Contrast enhancement was useful for the diagnosis of liver lesions suspected to be hepatocellular carcinoma by ordinary sonography, but could not be confirmed by color Doppler sonography.

Adult↗
PubMed1995

N-acetylation and N-formylation of carcinogenic arylamines and related compounds in dogs.

When sulfanilamide, p-aminobenzoic acid, 4-amino-biphenyl, 2-aminofluorene or 1-aminopyrene was given orally to dogs, the corresponding N-acetyl and N-formyl derivates were isolated from urine or feces. These metabolites were identified unequivocally by comparison with an authentic sample by UV and mass spectrometry and their behaviour in TLC and HPLC. Dog intestinal flora and several bacterial strains exhibited both N-acetylating and N-formylating activities, in varying degrees, toward all of the arylamines tested. The metabolites formed by the intestinal bacteria were also isolated and identified unequivocally. The results suggest that the intestinal microflora plays an important role in the formation of N-acyl derivatives from arylamines in dogs.

Acetylation↗