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Biomedical subjects

H Masuda

Publications and source records attributed to H Masuda.

At least 217 records · Page 12Linked to original sources
PubMed1997

[A clinicopathological study of 218 patients with bladder carcinoma treated by radical cystectomy].

Between 1986 and 1995, 218 patients with primary carcinoma of the bladder were treated with radical cystectomy at our hospitals. Clinicopathological specimens and the relative value of prognostic factors were analyzed with both the univariate and multivariate method. Univariate analysis indicated that age, sex, pathological tumor stage, grade, vessel involvement, tumor infiltrating type and positive nodes were predictive of poor cancer-specific survival. Multivariate analysis demonstrated that female patients were predictive of poor cancer-specific survival. As for the risk ratio, the prognostic factors in lymphatics involvement and tumor infiltrating type were 2.77 and 2.47, respectively.

Aged↗
PubMed1997

Immunosuppressive drugs inhibit the production of interleukin-6 and interleukin-8 in cultured cardiac myxoma cells.

Cardiac myxoma cells produce large amounts of interleukin (IL)-6 and IL-8. To determine whether immunosuppressive agents could be used to treat cardiac myxoma, we tested the effects of dexamethasone and three of the newer second-generation immunosuppressive drugs, cyclosporin A, tacrolimus, and deoxyspergualin, on the production of IL-6 and IL-8 in these cells. Cultured cardiac myxoma cells were used as in vitro model of cardiac myxoma. Cells were tested for 24 hours with 10(-7) M dexamethasone, 10(-6) M cyclosporin A, 10(-8) M tacrolimus, and 10(-6) M 15-deoxyspergualin, with aliquots of conditioned medium being assayed for cytokine levels at 0, 6, 12, and 24 hours. Cardiac myxoma cells isolated from 4 patients all produced quantities of IL-6 and IL-8. The concentrations of IL-6 in the medium after 7 days in culture ranged from 79,000 to 2,740,000 pg/ml, and the concentrations of IL-8 ranged from 40,000 to 1,000,000 pg/ml. Exposure of cyclosporin A and dexamethasone almost completely inhibited the production of IL-6 and IL-8 after 24 hours of treatment. Tacrolimus inhibited the production of both cytokines by 55%, while 15-deoxyspergualin reduced IL-6 levels by 24% and IL-8 levels by 48% after separate 24 hour treatments. These results suggest that these newer immunosuppressive agents may be useful in reducing the production of IL-6 and IL-8 in patients with cardiac myxoma.

Aged↗
PubMed1996

Isolation of a calcium-binding phosphoprotein from the oocytes and hemolymph of the blood-sucking insect Rhodnius prolixus.

A novel calcium-binding phosphoprotein was isolated from the oocytes of the blood-sucking bug Rhodnius prolixus. This protein exhibits an apparent molecular mass of 18 kDa on gel filtration, but migrates as an 8-kDa band on N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine/SDS-polyacrylamide gels. It has a high content of serine (24% of the total number of residues), and phosphoserine is the sole amino acid phosphorylated in vivo. A similar protein was partially purified from the hemolymph. It resembles the oocyte form of the protein in its NH2-terminal sequence and its ability to be taken up by growing ovaries. 45Ca binding to the oocyte phosphoprotein was determined after SDS-polyacrylamide gel electrophoresis followed by blotting on nitrocellulose membranes. Titration of Ca2+-binding sites shows a high capacity (approximately 50 mol/mol of protein), but a low affinity (K0.5 congruent with 10(-3) M). Based on these characteristics, we have named this protein Rhodnius calcium-binding phosphoprotein. It resembles phosvitin, a phosphoprotein present in the oocytes of nonmammalian vertebrates.

Amino Acid Sequence↗
PubMed1996

Sulphatide binds to human and animal influenza A viruses, and inhibits the viral infection.

We found, by using a virus overlay assay, that influenza A virus isolates bind to sulphatide (HSO3-Gal beta 1-->1'Cer), which has no sialic acid residue, and that the infection of Madin-Darby canine kidney cells with the human influenza virus A/Memphis/1/71 (H3N2) is inhibited by sulphatide. A/Memphis/1/71 (H3N2) causes obvious haemagglutination and low-pH haemolysis of asialoerythrocytes reconstituted with sulphatide. All influenza A virus isolates from the species of animals so far tested bound to sulphatide. The sulphatide-binding specificity of the isolates was different from the viral sialyl-linkage specificity. Influenza A virus isolates also bound to galactosyl ceramide (GalCer; Gal beta 1-->1'Cer), as well as sulphatide, in the virus overlay assays. In contrast, the influenza virus did not bind to N-deacyl, a derivative of sulphatide, glucosyl ceramide or the other neutral glycolipids tested. These results indicate that the linkage of galactose, or sulphated galactose, to ceramide is important for viral binding.

Animals↗
PubMed1996

Characterization and immunocytochemical localization of lipophorin binding sites in the oocytes of Rhodnius prolixus.

Purified lipophorin, metabolically labelled with 32P exclusively in the phospholipid moiety, was used to study the process of phospholipid delivery to the oocyte. The kinetics of phospholipid transfer "in vitro," from lipophorin to the oocytes, was linear at least up to 4 h and was impaired by low temperature. A net transfer of phospholipids from lipophorin particles to the oocytes was observed. The rate of phospholipid uptake was dependent on the concentration of lipophorin in the medium and was shown to be a saturable process. The addition of a molar excess of purified unlabelled lipophorin to the culture medium resulted in a substantial decrease in the transfer of [32P]phospholipids, but no reduction occurred in the presence of a molar excess of albumin. The lipophorin binding sites were localized in the oocytes by immunogold techniques using two different protocols for oocyte fixation. Strong labelling was observed especially at the microvilli. No labelling was detected in the yolk granules.

Animals↗
PubMed1996

Expression of 47 kDa heat shock protein (HSP47) during development of mouse cornea.

The 47-kDa heat shock protein (HSP47) is assumed to be a molecular chaperone specific to collagen. We examined and compared the expression patterns of HSP47 and alpha 1(I) collagen in the developing mouse cornea. Expression of HSP47 and alpha 1(I) collagen mRNAs was assessed by Northern blot analysis and in situ hybridization, and that of HSP47 protein was determined by Western immunoblotting and immunohistochemistry. HSP47 mRNA and protein were expressed strongly in early embryonic ocular tissues and were developmentally down-regulated during ocular development. Both were distributed in the mesenchymal cells (presumptive corneal stroma, sclera and choroid) and hyaloid blood vessels until post-natal day 14. The level of alpha 1(I) collagen mRNA increased during ocular development, was maximally expressed in the three days after birth, and was detected in mesenchymal cells. HSP47 expression is regulated developmentally toward completion and plays an important role during ocular development especially in corneal morphogenesis. We discuss here the relation between expression of HSP47 and alpha 1(I) collagen.

Animals↗
PubMed1996

Internal tissue displacement measurement based on ultrasonic wave Doppler signal digital detection and its application to fetal movement monitoring.

We have developed a fetal movement monitoring system based on small displacement measurement of internal tissues. When ultrasonic pulses are transmitted to the fetus, the reflected ultrasonic waves which have a Doppler frequency shift due to the fetal movements are detected by using an ultrasonic pulsed Doppler technique. In this paper, we propose a displacement measurement method for internal tissues which is based on the Doppler signal digital detection technique. In the method, the received ultrasonic RF signals are sampled with a sampling frequency of four times higher than the centre frequency of the ultrasonic waves; the Doppler frequency shift signals are derived using digital signal processing. From the detected signals, the internal displacements are estimated using the arc-tangent method. The basic algorithm of the detection method has already been used in the area of blood flow sensing, however, we apply the algorithm to the displacement measurement of internal tissues. The comparison between the proposed method and the conventional method is presented. The fetal movement quantitative monitoring system based on the method which has been constructed is shown.

Algorithms↗
PubMed1996

Developmental changes in beta-adrenergic and muscarinic modulations of Ca2+ currents in fetal and neonatal ventricular cardiomyocytes of the rat.

Developmental changes of the beta-adrenergic and muscarinic modulations acting on the slow Ca2+ channels in rat ventricular cardiomyocytes were investigated using Ba2+ as the charge carrier (IBa(L)). Single cardiomyocytes from fetal and neonatal rats were freshly isolated, and currents were recorded by whole-cell voltage clamp in Na(+)-free, K(+)-free external solution. Basal current densities showed a large increase between fetal days 15 and 18, and a small decrease after fetal day 20. The ability of isoproterenol (ISO, 1 microM) to enhance IBa(L) increased dramatically between fetal days 18 and 20, and remained almost constant thereafter during the neonatal period. The ability of forskolin (FOR, 10 microM) to stimulate IBa(L) also increased markedly between fetal day 18 and neonatal day 1. Carbachol (CCh), in a dose-dependent manner, reversed the stimulation of the IBa(L) produced by ISO in neonatal cardiomyocytes. The IC50 values for CCh inhibition of IBa(L) was almost the same on all neonatal days tested (neonatal days 1, 5 and 10). The results indicate that there are developmental changes in beta-adrenergic modulation of IBa(L) in the late fetal period, including a large jump in sensitivity to ISO on about fetal day 19. These findings are consistent with the steep increase in number of beta-adrenergic receptors that occurs between fetal days 18 and 20 (Kojima, Sperelakis & Sada, 1990a: Kojima, Ishima, Taniguchi, Kimura, Sada & Sperelakis, 1990C).

Adrenergic beta-Agonists↗
PubMed1996

Laparoscopic adrenalectomy for nonfunctioning adrenal tumors.

Thirteen patients who underwent laparoscopic adrenalectomy for nonfunctioning adrenal tumors were compared with seven patients who underwent open adrenalectomy. Although a longer operating time was required for laparoscopic surgery, postoperative recovery was significantly more rapid. Performance of adrenalectomy for nonfunctioning adrenal tumors is controversial, but we cannot exclude the possibility of malignancy and the potential for hormone overproduction by presumably nonfunctioning small tumors. The minimally invasive nature of laparoscopic surgery may widen the indications for adrenalectomy in patients with nonfunctioning adrenal tumors.

Adolescent↗
PubMed1996

Molecular cloning and characterization of human non-smooth muscle calponin.

cDNA clones encoding a calponin isoform with 309 amino acids have been isolated from human heart. The deduced amino acid polypeptide (M(r) 33,697) showed a neutral isoelectric point of 7.1. The mRNA, expressed in cultured smooth muscle cells as well as in fibroblasts, vascular endothelial cells, and keratinocytes, contains a 3' untranslated region of 1.2 kilobases that includes an Alu repetitive sequence in the antisense direction. On the basis of the nucleotide sequence identity to an expressed sequence tag, HUM21ES93 [Cheng, J.-F., Boyartchuk, V., and Zhu, Y. (1994) Genomics 23, 75-84], the human neutral calponin gene is assigned to chromosome 21q11.1. The amino acid sequence indicates that this protein is the human equivalent of mouse calponin-h2 (94.8% identity) [Strasser, P., Gimona, M., Moessler, H., Herzog, M., and Small, J.V. (1993) FEBS Lett. 330, 13-18]. Three tandem repeats of 29 amino acids, a Vav-homologous region and an actin-binding sequence, originally identified in the basic calponin isoform, are conserved. There are two consensus phosphorylation sites for tyrosine kinase. An immunoreactive form of the neutral calponin appears to be localized with vinculin in the cell-to-cell junctions of cardiomyocytes. Mouse calponin-h2 is also expressed in both embryonic and adult heart. These results indicate that the human neutral calponin is a non-smooth muscle isoform, and may play a physiological role in cytoskeletal organization.

Adult↗
PubMed1996

Aortic intimal sarcoma with acute myocardial infarction.

An autopsy case of aortic sarcoma who died of acute myocardial infarction caused by coronary involvement is reported. The patient was a 54 year old woman who was admitted because of an undiagnosed fever and general fatigue of 6 months duration. Magnetic resonance imaging (MRI) showed a tumor in the aortic arch. Total aortic arch replacement was performed. It was diagnosed as a malignant mesenchymal tumor of the aorta. The patient died of acute myocardial infarction 10 months after the operation. At autopsy, the tumor had invaded the luminal surface and intima of the proximal anastomosis (the remnant ascending aorta and the graft), the aortic valves, the distal anastomosis (surgical line of the thoracic aorta plus the graft), and the coronary arteries. The left main coronary artery showed complete obstruction by fibrin thrombus with tumor invasion in the intima, which was responsible for acute myocardial infarction. Primitive and bizarre tumor cells proliferated with many slit-like tissue spaces. Most of the tumor except for its luminal surface showed necrosis. Ultrastructurally, there were spaces between tumor cells, suggesting lumen formation, and some of them had microvilli. This sarcoma was considered to be the so-called aortic intimal sarcoma.

Aortic Diseases↗
PubMed1996

Rate of nitric oxide release in the lung and factors influencing the concentration of exhaled nitric oxide.

The level of nitric oxide (NO) in exhaled air fluctuates in normal individuals depending on the physiological conditions. We evaluated the effects of duration of exhalation and breath-holding on the exhaled concentrations of NO in 16 normal human volunteers. Exhaled gas corresponding to vital capacity was collected in 6-liter Tedlar bags and analyzed by chemiluminescence. The NO concentration in exhaled gas increased significantly in proportion to the duration of exhalation [P = 0.009 +/- 0.011 (SD)] and was increased after breath-holding. There was no significant difference in the exhaled NO concentration among 10-s phases of a 30-s exhalation, as determined from multiple breath collections. The NO released from the airways is presumably unaffected by fluctuation of exhalation speed. The NO release rate, calculated from a single regression analysis between the NO concentration and the duration of exhalation, was 39 +/- 29 pmol/s, a value which was about fourfold greater in nine patients with bronchial asthma.

Adult↗
PubMed1996

Role of gamma-tubulin in mitosis-specific microtubule nucleation from the Schizosaccharomyces pombe spindle pole body.

The ability of the Schizosacchromyces pombe spindle pole body to nucleate microtubules is activated at the onset of mitosis for forming a mitotic spindle, but it is inactivated during interphase. We have previously developed an in vitro assay for studying the molecular mechanism of spindle pole body activation using permeabilized interphase S. pombe cells and Xenopus mitotic extracts. We have shown that the interphase spindle pole body is activated indirectly by p34cdc2 protein kinase in Xenopus mitotic extracts. In this study we examined the role of gamma-tubulin, a component of both interphase and mitotic spindle pole body, in formation of the microtubule nucleating complex at the mitotic spindle pole body. A polyclonal antibody specific to S. pombe gamma-tubulin inhibited both activation of the interphase spindle pole body and microtubule nucleation from the mitotic spindle pole body. Addition of bacterially expressed S. pombe gamma-tubulin or its amino-terminal fragments to Xenopus mitotic extracts inhibited spindle pole body activation. Affinity chromatography of partially fractionated Xenopus mitotic extracts with the amino-terminal fragment of S. pombe gamma-tubulin showed that fractions bound to the fragment supported the activation. The fractions did not contain Xenopus gamma-tubulin, showing that activation of the spindle pole body is not due to recruitment of Xenopus gamma-tubulin to the spindle pole body. The spindle pole body activation occurred in extracts depleted of p34cdc2 protein kinase or MAP kinase. The activity of the fractions bound to the fragment was inhibited by a protein kinase inhibitor, staurosporine. These results suggest that S. pombe gamma-tubulin is a component of the microtubule nucleating complex, and that the function of proteins that interact with gamma-tubulin is required for activation of the spindle pole body. We present possible models for the activation that convert the immature microtubule nucleating complex at interphase into the mature microtubule nucleating complex at mitosis.

Amino Acid Sequence↗
PubMed1996

Intraperitoneal administration of Senegae Radix extract and its main component, senegin-II, affects lipid metabolism in normal and hyperlipidemic mice.

The hypolipidemic effect of Senegae Radix, i.e. "Senega," was investigated in normal and hyperlipidemic mice. The n-butanol fraction of the methanol extract of Senegae Radix (SN) (5 mg/kg) significantly reduced the blood triglyceride level of normal mice 7 h after intraperitoneal administration (p < 0.05) and also significantly reduced the blood triglyceride level of cholesterol-fed mice under similar conditions (p < 0.05). SN (5 mg/kg) also reduced the blood triglyceride and cholesterol levels after repeated administration to cholesterol-fed mice. SN also decreased the blood triglyceride level in Triton-induced hyperlipidemia. It is suggested that this fraction contains one or more hypolipidemic components including the main triterpenoid glycoside, senegin-II, which significantly reduces the levels of blood triglycerides in normal mice.

Animals↗
PubMed1996

Effect of astilbin in tea processed from leaves of Engelhardtia chrysolepis on the serum and liver lipid concentrations and on the erythrocyte and liver antioxidative enzyme activities of rats.

The effects of astilbin in Kohki tea, which is produced from the leaves of Engelhardtia chrysolepis Hance (Chinese name, huang-qui), and of an aglycone of astilbin, taxifolin, on the serum and liver lipid concentrations, and on the erythrocyte and liver antioxidative enzyme activities were determined with rats fed on a cholesterol-free diet. The total liver cholesterol concentration tended to be decreased by feeding with astilbin, and significantly decreased by feeding with taxifolin. The liver phospholipid concentration was decreased by feeding with both astilbin and taxifolin. In addition, astilbin and taxifolin lowered the serum and liver TBARS concentrations, but did not influence the serum and liver antioxidative enzyme activities, suggesting the possibility that these compounds acted to lower the TBARS concentration by their direct antioxidative action in vivo, almost without influencing the antioxidative enzyme activities.

Animals↗
PubMed1996

Protection against oxidative damage by dihydroflavonols in Engelhardtia chrysolepis.

Dihydroflavonol taxifolin and its glycoside, astilbin, from Engelhardtia chrysolepis were evaluated as antioxidants and radical scavengers. These dihydroflavonols inhibited superoxide anion production in the xanthine/xanthine oxidase system. Microsomal lipid peroxidation induced by NADPH-cytochrome P-450 reductase was also inhibited by these flavonoids. Mitochondrial lipid peroxidation was inhibited only by the aglycon. Taxifolin protected peroxy radical-damaged mitochondria with no effect on enzyme activity. Furthermore, taxifolin and astilbin protected red cells against oxidative hemolysis. These dihydroflavonols were found to be effective for protecting subcellular systems and red blood cells against oxidative stress in vitro.

Animals↗