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Biomedical subjects

S Goto

Publications and source records attributed to S Goto.

At least 109 records · Page 6Linked to original sources
PubMed2001

The inhibitory effect of simvastatin on growth in malignant gliomas--with special reference to its local application with fibrin glue spray in vivo.

Simvastatin is one of the competitive inhibitors of HMG-CoA reductase. During clinical trials, it has shown the ability to lower serum cholesterol. We investigated the effect of simvastatin on the growth of malignant gliomas in vitro, semi-in vivo, and in vivo. An in-vitro MTT assay revealed that human malignant glioma cell lines: U-251MG, U-373MG, and U-87MG, and rat malignant glioma cell line C6 were well inhibited in growth in a dose-dependent fashion. An anchorage-independent growth assay showed that the number of colonies (more than 100 microM in size) of human (U-373MG) and rat malignant gliomas (C6) was markedly reduced in a dose-dependent fashion. A flow cytometry analysis revealed that simvastatin treatment led U-251MG cells to accumulate in sub G0-G1. Immunostaining by TUNEL method showed that most glioma cells treated by 10 microM simvastatin had nuclear immunostaining, suggesting apoptotic changes of the treated cells. The human umbilical vein endothelial cells and human lung fibroblasts were inhibited in growth by no more than 20% of controls even with a high dose (10 microM) of simvastatin. In the semi-in vivo model, using newborn rat brain slice cultures, the rhodamine-labeled glioma cells were abolished after 7 days of local simvastatin treatment with fibrin glue probably suggesting that simvastatin led the cells to apoptosis. In rat models using subcutaneously inoculated C6, the local application of simvastatin combined with fibrin glue (spray method) was quite effective in inhibiting the growth of the tumor. These data suggest that simvastatin may be a novel anti-glioma drug, and the local application of simvastatin combined with fibrin glue (by spray method) may be a crucial new clinical strategy against glioma growth.

Animals↗
PubMed2001

Development of Ag-Pd-Au-Cu alloys for multiple dental applications. Part 2. Mechanical properties of experimental Ag-Pd-Au-Cu alloys containing Sn or Ga for ceramic-metal restorations.

Eighteen Ag-Pd-Au-Cu alloys, consisting of nine Ag-Pd-Au-Cu mother compositions (Pd: 20, 30 or 40%, Au: 20%, Cu: 10, 15 or 20%, Ag: balance) containing either 5% Sn or 5% Ga as an additive metal, were experimentally prepared. Tensile strength, proof stress, elongation, elastic modulus, and Vickers hardness of these alloys were evaluated to clarify the potential of these alloys for use as ceramic-metal restorations as well as the effects of the Pd and Cu contents on their mechanical properties. The tensile strength, proof stress, elongation, elastic modulus and Vickers hardness of the 18 experimental alloys were in the range of 410.0-984.0 MPa, 289.7-774.3 MPa, 2.2-23.7%, 81.3-123.0 GPa and 135.7-332.3 HV1, respectively. Ten of the 18 experimental alloys can be used for ultra-low fusing ceramics based on their proof stress, elastic modulus, elongation and hardness. Between the Ga- and Sn-added alloys, differences in tensile strength, proof stress, elongation and hardness were found at several Ag-Pd-Au-Cu compositions.

Analysis of Variance↗
PubMed2001

Effects of Sn, Ga, and In additives on properties of Ag-Pd-Au-Cu alloy for ultra-low fusing ceramics.

Nine 35% Ag-30% Pd-20% Au-15% Cu alloys containing 2, 4 and 6 mass% of Sn, Ga or In as an additive metal were experimentally prepared to investigate the effects of different additives and their content on the physical and mechanical properties as well as the bond with a ultra-low fusing ceramic. Both the different additives and their content or either of these two factors significantly influenced most of the evaluated properties except for the area fraction of the retained ceramic. Based on the evaluated properties three experimental alloys (2% Sn-added alloy, 4% Ga-added alloy and 2% In-added alloy) can be recommended as a suitable alloy for ceramic-metal restorations using ultra-low fusing ceramics.

Analysis of Variance↗
PubMed2001

[Evaluation of the conjunctiva of leprosy patients using impression cytology].

OBJECTIVE: To evaluate ocular surface disorders (OSD) similar to cicatricial pemphigoid in leprosy patients. SUBJECT AND METHOD: Sixteen leprosy patients were examined. They were under treatment as inpatients at the Tama Zenshoen National Sanatorium, an institution for the treatment of leprosy. In addition to routine ophthalmological examinations, the patients conjunctival goblet cells were examined using impression cytology. OSD similar to ocular cicatricial pemphigoid were defined as the presence of at least two items of the following: symblepharon, cicatricial contraction of the conjunctival sac, corneal neovascularization, and palpebral entropion. RESULTS: OSD was present in 8 of the 16 patients (50%). Goblet cells were either decreased in number or absent in 7 cases(44%), and included 4 cases with OSD. Six of the 7 cases(86%) with reduced or absent goblet cells had been diagnosed as leprosy prior to 1944. CONCLUSION: Reduction or absence of goblet cells is a frequent feature in leprosy patients, particularly in longstanding ones of 56 years or more. Insufficient initial treatment appears to be a major cause of this finding.

Aged↗
PubMed2001

[Factors allowing continuous working of female nurses in the People's Republic of China--survey of 15 hospitals in 5 areas].

PURPOSE: Few investigations have been conducted on working, childcare and home education among female nurses (nurses) in the People's Republic of China (P.R. of China). The purpose of this study was to clarify the factors allowing continued working of female nurses. METHODS: The subjects were nurses from 15 hospitals in 3 provinces and 2 autonomous areas. They were surveyed by questionnaire regarding their childcare and home education. In was distributed by the Ministry of Health in the P.R. of China and the data were collected between February and April in 1996. RESULTS: A total of 4,284 (80.0%) questionnaires were collected. 1. About 60% of the nurses began working when they were 15 to 19 years old. The average length of service was 13.9 years. 2. Their professional position correlated directly with their years of service. 3. 4.3% of them had not continued working. 4. The nurses entrust their children to day-care institutions (61.2%) or grandparents (22.3%) during the daytime, and to the father (66.3%) or the grandparents (19.5%) during the night. 5. 17.6% of them have experienced being away from home for more than one month due to their job. 6. 66.8% of the nurses have experienced more than one month official trip, and had children under 14 years old at the time. They entrusted their children to day-care institutions (34.1%), to the father (29.2%) and grandparents (25.3%) during the official trip. CONCLUSIONS: In summary, most nurses are employed when they are young and go on working as nurses. It is possible for them to continue their work after marriage, childbirth, and while they are bringing up their children. The high rate of working woman, sufficient nursery schools and family cooperation in housework can be pointed out as main factors that enable them to continue their work.

Adolescent↗
PubMed2001

[Childcare and home education in families of female nurses in the People's Republic of China--survey of 15 hospitals in 5 areas].

PURPOSE: The purpose of this study was to investigate the actual conditions of childcare and home education among families of female nurses in the P. R. of China. METHODS: The subjects were nurses from 15 hospitals in 3 provinces and 2 autonomous areas. They were surveyed by questionnaire regarding their childcare and home education. It was distributed by the Ministry of Health in the P. R. of China and data were collected between February and April in 1996. RESULTS: A total of 4284 (80.0%) questionnaires were collected. 1. The age of the subjects was between 18 and 62 years old with a mean of 32.9 +/- 9.0 (SD) years 71.4% of them had husbands, whose ages were between 23 and 71 years old, the mean age being 38.3 +/- 8.4 (SD) years. The family types were 63.2% nuclear family and 33.7% extended family, with 3.1% being single. 65.1% of the subjects had children, whose mean number was 1.1 +/- 0.4 (SD). Firstborn children were 49.9% girls and 50.1% boys. 2. The most popular method of infant nutrition was breast-feeding, utilized by 60.1%. The highest rate (67.8%) was in the age group of 25 to 29 years old (P < 0.01). 3. The practice of "swaddling" (wrapping the child so as not to allow movement) was more common in the over 40 year old age group than the under 40 year old group (P < 0.01). Swaddling-practice showed significant differences by area. 4. The rates for children who helped with housework were 50.3% for girls and 46.7% for boys. 5. A number of children between 7 and 18 years old were studying English privately. 6. The greatest expectation of the subjects, for their children aged between 7 and 18 years old, was to study. CONCLUSIONS: 1. Infant nutrition showed significant differences between generations, and swaddling-practice differed with the generation and the area. 2. Although girls help their parents more than boys in Japan, boys and girls equally helped their parents in the P. R. of China. 3. Concerning the topics of private learning and parents expectations, the results were similar to those in Japan.

Adolescent↗
PubMed2001

Role of von Willebrand factor for the onset of arterial thrombosis.

Von Willebrand factor, a multimeric plasma protein released from either vascular endothelial cells or platelets, has been recently shown to play a crucial role in platelet thrombosis at sites exposed to high shear stress. Since VWF is only stored in two cellular components in normal adults, platelets and endothelial cells, the local release of VWF is an important regulatory mechanism of local thrombogenicities. Since endothelial cells are a larger source of plasma VWF, plasma VWF concentration can be used as an indicator of certain endothelial functions. Moreover, VWF is now being considered as a new target for the development of antithrombotic agents because the inhibition of VWF-mediated thrombosis may result in selective inhibition of platelet thrombosis at sites exposed to high shear stress, such as in atherosclerotic stenotic coronary arteries, without bleeding complications.

Arterial Occlusive Diseases↗
PubMed2001

[Usefulness of combination post-stress dysfunction and perfusion imaging in technetium-99m-tetrofosmin myocardial scintigraphy].

OBJECTIVES: Myocardial perfusion imaging has lower sensitivity for the diagnosis of coronary artery disease in patients with three-vessel disease. The presence of post-stress dysfunction of the left ventricle, evaluated by electrocardiography(ECG) gated single photon emission computed tomography(SPECT) with a quantitative gated SPECT program, was investigated in patients with coronary artery disease, and also whether combining post-stress dysfunction and myocardial perfusion imaging improved the diagnosis of coronary artery disease. METHODS: ECG gated technetium-99m-tetrofosmin SPECT was performed using a one day, stress and rest, protocol in 139 patients. SPECT and coronary angiography were performed within 1 month. The coronary artery disease group consisted of 89 patients: 43 with one-vessel disease(1VD), 28 with two-vessel disease(2VD), and 18 with three-vessel disease(3VD). The group with zero-vessel disease(0VD) consisted of 50 patients. According to post-stress and rest ejection fraction(EF) and end-systolic volume (ESV), post-stress dysfunction is defined as follows: rest EF--post-stress EF > or = 5% and post-stress ESV--rest ESV > or = 5 ml. RESULTS: In the coronary artery disease group, post-stress ESV was larger than rest ESV(37.8 +/- 26.4, 34.0 +/- 24.2 ml, p < 0.001), and post-stress EF was lower than rest EF (61.5 +/- 11.1%, 64.2 +/- 10.8%, p < 0.001). In the 0VD group, ESV and EF were the same for post-stress and rest (25.7 +/- 20.8, 26.2 +/- 21.6 ml, NS; 70.4 +/- 9.5%, 70.0 +/- 9.6%, NS). Post-stress dysfunction was 6.0% in the 0VD group and 30.3% in the coronary artery disease group(p < 0.001). Furthermore, post-stress dysfunction in the 2VD (35.7%) and 3VD(38.9%) groups was higher than that in the 0VD group(p < 0.01, p < 0.01). Sensitivity of coronary artery disease diagnosis by myocardial perfusion imaging was 75%. The combination of post-stress dysfunction and myocardial perfusion imaging improved sensitivity from 75% to 82%(p < 0.05), but reduced the specificity from 92% to 86%(p = 0.08). CONCLUSIONS: Post-stress dysfunction is a useful parameter for clinical diagnosis of coronary artery disease.

Aged↗
PubMed2001

Adaptation to exercise-induced oxidative stress: from muscle to brain.

Exercise increases the generation of reactive oxygen and nitrogen species (RONS) and by causing adaptation, could decrease the incidence of RONS-associated diseases. A single bout of exercise, depending upon intensity and duration, can cause an increase in antioxidant enzyme activity, decrease levels of thiols and antioxidant vitamins, and result in oxidative damage as a sign of incomplete adaptation. Increased levels of RONS and oxidative damage are initiators of a specific adaptive response, such as the stimulation of the activation of antioxidant enzymes, thiols, and enhanced oxidative damage repair. Regular exercise has the capability to develop compensation to oxidative stress, resulting in overcompensation against the increased level of RONS production and oxidative damage. Regular exercise causes adaptation of the antioxidant and repair systems, which could result in a decreased base level of oxidative damage and increased resistance to oxidative stress.

Adaptation, Biological↗
PubMed2001

Role of root hairs and lateral roots in silicon uptake by rice.

The rice plant (Oryza sativa L. cv Oochikara) is known to be a Si accumulator, but the mechanism responsible for the high uptake of Si by the roots is not well understood. We investigated the role of root hairs and lateral roots in the Si uptake using two mutants of rice, one defective in the formation of root hairs (RH2) and another in that of lateral roots (RM109). Uptake experiments with nutrient solution during both a short term (up to 12 h) and relatively long term (26 d) showed that there was no significant difference in Si uptake between RH2 and the wild type (WT), whereas the Si uptake of RM109 was much less than that of WT. The number of silica bodies formed on the third leaf in RH2 was similar to that in WT, but the number of silica bodies in RM109 was only 40% of that in WT, when grown in soil amended with Si under flooded conditions. There was also no difference in the shoot Si concentration between WT and RH2 when grown in soil under upland conditions. Using a multi-compartment transport box, the Si uptake at the root tip (0-1 cm, without lateral roots and root hairs) was found to be similar in WT, RH2, and RM109. However, the Si uptake in the mature zone (1-4 cm from root tip) was significantly lower in RM109 than in WT, whereas no difference was found in Si uptake between WT and RH2. All these results clearly indicate that lateral roots contribute to the Si uptake in rice plant, whereas root hairs do not. Analysis of F(2) populations between RM109 and WT showed that Si uptake was correlated with the presence of lateral roots and that the gene controlling formation of lateral roots and Si uptake is a dominant gene.

Cell Surface Extensions↗
PubMed2001

Extraction of correlated gene clusters by multiple graph comparison.

This paper presents a new method to extract a set of correlated genes with respect to multiple biological features. Relationships among genes on a specific feature are encoded as a graph structure whose nodes correspond to genes. For example, the genome is a graph representing positional correlations of genes on the chromosome, the pathway is a graph representing functional correlations of gene products, and the expression profile is a graph representing gene expression similarities. When a set of genes are localized in a single graph, such as a gene cluster on the chromosome, an enzyme cluster in the metabolic pathway, or a set of coexpressed genes in the microarray gene expression profile, this may suggest a functional link among those genes. The functional link would become stronger when the clusters are correlated; namely, when a set of corresponding genes form clusters in multiple graphs. The newly introduced heuristic algorithm extracts such correlated gene clusters as isomorphic subgraphs in multiple graphs by using inter-graph links that are defined based on biological relevance. Using the method, we found E.coli correlated gene clusters in which genes are related with respect to the positions in the genome and the metabolic pathway, as well as the 3D structural similarity. We also analyzed protein-protein interaction data by two-hybrid experiments and gene coexpression data by microarrays in S.cerevisiae, and estimated the possibility of utilizing our method for screening the datasets that are likely to contain many false positive relations.

Algorithms↗
PubMed2001

[Determination of 35 polycyclic aromatic hydrocarbons in airborne suspended particulate by GC/MS].

OBJECTIVE: To establish capillary column GC/MS method for the determination of 35 polycyclic aromatic hydrocarbons (PAHs) in airborne suspended particulate. METHODS: The air samples collected by an electrostatic particle collector were Soxhlet-extracted using 3:1 benzene/ethanol, and then subjected to the procedures of concentration and clean-up. Finally, the target PAHs were determined by the proposed method. RESULTS: All the target PAHs could be well separated except for benzo[b] fluoranthene, benzo[j] fluoranthene and benzo [k] fluoranthene through temperature programming. The relative standard deviations of the method were 1.8%-17.7% and the recoveries ranged from 93.4% to 101.9%. The absolute detection limit ranged from 0.0001 ng to 0.1 ng. CONCLUSION: The method is applicable to the determination of more than 30 PAHs in the airborne suspended particulate samples.

Air Pollutants↗
PubMed2000

Crystallization in low-energy deposition of titanium ions.

To investigate crystallization in the ion beam deposition process, titanium ions were deposited on silicon wafers at 105 and 55 eV. As titanium is an active metal, titanium compounds are formed by absorbing backfilled or residual gas. At energy levels of 105 or 55 eV, titanium crystallizes in a NaCl-type titanium compound with the backfilling of air. In all samples, (110)-oriented crystals grew with a rectangular lattice arrangement of titanium atoms. The open channel <110> of preferentially oriented crystal growth was parallel to the direction of incident ions normal to the substrate surface.

Journal Article↗
PubMed2000

Enhanced shear-induced von Willebrand factor binding to platelets in acute myocardial infarction.

Recent investigations have suggested that von Willebrand factor (vWF) plays a crucial role in platelet thrombosis under flow conditions. The effects of plasma obtained from 15 patients with acute myocardial infarction and 10 patients with the chest pain syndrome as controls, on shear-induced vWF binding to platelets and subsequent platelet activation, as evidenced by microparticle release, were investigated by quantitative flow cytometry. Platelet-rich plasma was obtained from a 38-year-old healthy male volunteer with blood type O. Stored plasma from either the acute myocardial infarction or control patients was then added to the freshly prepared platelet-rich plasma in equal volumes. The mixtures were then exposed to specific shear rates in an optically modified cone-plate viscometer. The number of vWF molecules bound to the platelet surface and the number of microparticles released from the platelets were then measured by quantitative flow cytometry using an FITC-conjugated anti-vWF monoclonal antibody. The shear-induced increase in vWF binding to the platelet surface was enhanced in the presence of plasma from patients with acute myocardial infarction (acute myocardial infarction plasma). The shear-induced release of microparticles from platelets was enhanced from 889+/-134 in the presence of control plasma to 1045+/-222 in the presence of the acute myocardial infarction plasma (p<0.05). Acute myocardial infarction plasma also reduced the shear rate threshold required to induce measurable shear-induced vWF binding from 10800 s(-1) to 9000 s(-1). We conclude that the plasma of acute myocardial infarction patients contains factors that enhance shear-induced vWF binding and vWF-mediated platelet activation, which may contribute to thrombotic re-occlusions of the coronary arteries in patients who have received reperfusion treatments.

Aged↗
PubMed2000

Regular training modulates the accumulation of reactive carbonyl derivatives in mitochondrial and cytosolic fractions of rat skeletal muscle.

The oxygen flux into the mitochondria of skeletal muscle increases with exercise. However, the extent of oxidative damage to mitochondrial proteins of skeletal muscle has only been estimated. We studied the alteration of reactive carbonyl derivatives (RCD) in mitochondrial and cytosolic fractions of skeletal muscle following 9 weeks of swimming training in rats. The RCD content of mitochondria was significantly elevated compared with the cytosolic fraction of both control and exercised animals. Accumulation of RCD in muscle mitochondria of the exercised group was also significantly elevated (P < 0.05). On the other hand, alteration of the accumulation of RCD was not apparent in the cytosolic fraction of skeletal muscle. The activity of proteasome complex, however, was increased in the cytosolic fraction of exercised muscle (P < 0.05). The data suggest that mitochondria of skeletal muscle accumulate significantly larger amounts of RCD than the cytosolic fraction and the tendency of the accumulation varies in cell fractions. Exercise training increases the accumulation of protein damage in mitochondria of skeletal muscle but cytosolic proteins are protected by increased activity of proteasome complex and possibly by other antioxidant enzymes.

Animals↗
PubMed2000

A heuristic graph comparison algorithm and its application to detect functionally related enzyme clusters.

The availability of computerized knowledge on biochemical pathways in the KEGG database opens new opportunities for developing computational methods to characterize and understand higher level functions of complete genomes. Our approach is based on the concept of graphs; for example, the genome is a graph with genes as nodes and the pathway is another graph with gene products as nodes. We have developed a simple method for graph comparison to identify local similarities, termed correlated clusters, between two graphs, which allows gaps and mismatches of nodes and edges and is especially suitable for detecting biological features. The method was applied to a comparison of the complete genomes of 10 microorganisms and the KEGG metabolic pathways, which revealed, not surprisingly, a tendency for formation of correlated clusters called FRECs (functionally related enzyme clusters). However, this tendency varied considerably depending on the organism. The relative number of enzymes in FRECs was close to 50% for Bacillus subtilis and Escherichia coli, but was <10% for SYNECHOCYSTIS: and Saccharomyces cerevisiae. The FRECs collection is reorganized into a collection of ortholog group tables in KEGG, which represents conserved pathway motifs with the information about gene clusters in all the completely sequenced genomes.

Algorithms↗
PubMed2000

Lipophilic HMG-CoA reductase inhibitor has an anti-inflammatory effect: reduction of MRNA levels for interleukin-1beta, interleukin-6, cyclooxygenase-2, and p22phox by regulation of peroxisome proliferator-activated receptor alpha (PPARalpha) in primary endothelial cells.

We examined the effects of four 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (pravastatin, simvastatin, fluvastatin, and cerivastatin) on the production and expression of inflammatory cytokines and on enzyme expression involving prostaglandin and superoxide production in cultured human umbilical vein endothelial cells (HUVEC). All HMG-CoA reductase inhibitors significantly reduced interleukin-1beta and -6 mRNA expression and their protein levels in the culture medium, and also inhibited cyclooxygenase-2 mRNA expression and their protein levels. And these drugs induced peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma mRNA expression and their protein levels in HUVEC and hepatocyte. Moreover, the mRNA levels of p22phox, a 22-kD subunit and the protein levels of p47phox, a 47-kD subunit of nicotine adenine dinucleotide phosphate (NADPH) oxidase, was decreased by treatment with either simvastatin, fluvastatin or cerivastatin, and this effect was reversed by mevalonate, geranylgeraniol, farnesol, and cholesterol. The changes induced by HMG-CoA reductase inhibitors might be due to regulation of cellular cholesterol content level, cellular cholesterol metabolic pathway, and cellular PPARalpha activity, which was related with inflammation. This unique anti-inflammatory effect in addition to its hypolipidemic action, may be beneficial in preventing the vascular complications that are induced by hyperlipidemia.

Anti-Inflammatory Agents↗