Search PubMed⌕ Search

Biomedical subjects

Y Murakami

Publications and source records attributed to Y Murakami.

At least 271 records · Page 15Linked to original sources
PubMed1999

MN/CA9 gene expression as a potential biomarker in renal cell carcinoma.

OBJECTIVE: To compare the levels of MN/CA9 expression with clinicopathological variables in renal cell carcinoma (RCC), and thus evaluate MN/CA9 expression as a possible biomarker for RCC. MATERIALS AND METHODS: The level of expression of MN/CA9 was evaluated in 76 surgically obtained tissue samples (49 from RCC, 22 from normal kidney and five from oncocytoma) using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis. In RCC, MN/CA9 expression was compared with stage, grade and cell type. RESULTS: MN/CA9 was expressed in 42 of 49 (86%) RCC samples, but in only two of 22 (9%) normal kidney and none of five oncocytoma samples. Levels of MN/CA9 expression were significantly higher in tumours consisting only of clear cells than in those containing other cell types (P=0.0189), and MN/CA9 was expressed in 34 of 37 (92%) RCC samples consisting only of clear cells. Tumours of low clinical stage showed a striking increase in MN/CA9 expression, and high MN/CA9 expression was associated with a good patient outcome. CONCLUSION: These results suggest that MN/CA9 expression is a potential diagnostic biomarker of RCC, especially the clear-cell type, and can be targeted using molecular biological techniques.

Adult↗
PubMed1999

Effects of erythropoietin on neuronal activity.

Recently, erythropoietin (EPO) receptors and synthesis of EPO have been identified in the brain. To clarify the effects of EPO on neuronal cells, we investigated the effects of EPO on Ca2+ uptake, intracellular Ca2+ concentration, membrane potential, cell survival, release and biosynthesis of dopamine, and nitric oxide (NO) production in differentiated PC12 cells, which possess EPO receptors. EPO (10(-12)-10(-10) M) increased 45Ca2+ uptake and intracellular Ca2+ concentration in PC12 cells in a dose-related manner; these increases were inhibited by nicardipine (1 microM) or anti-EPO antibody (1:100 dilution). EPO induced membrane depolarization in PC12 cells. After a 5-day culture without serum and nerve growth factor (NGF), viable cell number decreased to 50% of that of the control cells cultured with serum and NGF. EPO (10(-13)-10(-10) M) increased the number of viable cells cultured without serum and NGF; this increase was blunted by nicardipine or anti-EPO antibody. Incubation with EPO (10(-13)-10(-10) M) stimulated mitogen-activated protein kinase activity in PC12 cells. EPO (10(-13)-10(-10) M) increased dopamine release from PC12 cells and tyrosine hydroxylase activity; these increases were sensitive to nicardipine or anti-EPO antibody. Following a 4-h incubation with EPO (10(-14)-10(-10) M), NO production was increased, which was blunted by nicardipine and anti-EPO antibody. In contrast, maximal NO synthase activity was not changed by EPO. These results suggest that EPO stimulates neuronal function and viability via activation of Ca2+ channels.

Animals↗
PubMed1999

Postoperative toxic shock syndrome caused by a highly virulent methicillin-resistant Staphylococcus aureus strain.

We report on a rare fatal case of postoperative toxic shock syndrome caused by infection with a highly virulent methicillin-resistant Staphylococcus aureus strain, designated Sak-1, which was found to be characteristic in its increased production of toxic shock syndrome toxin 1 in human whole blood (about 30-fold more than produced in Tod Hewitt broth). The strain also produced a high level of toxic shock syndrome toxin 1 in the circulating blood of mice experimentally infected with the strain.

Adult↗
PubMed1999

Purification and characterization of cold-active L-glutamate dehydrogenase independent of NAD(P) and oxygen.

L-Glutamate dehydrogenase (GLDH) independent of NAD(P) and oxygen was first obtained from the psychrotrophic bacterium Aeromonas sp. L101, originally isolated from the organs of salmon (Oncorhynchus keta). GLDH was purified by a series of chromatography steps on DEAE-Sepharose, Superdex 200pg, Q-Sepharose, CM-Sepharose, and Phenyl-Sepharose. The purified protein was determined to have a molecular mass of 110 kDa and a pI of 5.7. Maximum activity was obtained at 55 degrees C and pH 8.5. The activity of GLDH at 4 and 20 degrees C was 38 and 50%, respectively, of that at 50 degrees C. GLDH was coupled to cytochrome c and several redox dyes including 1-methoxy-5-methylphenazinium methylsulfate (1-Methoxy PMS), 2, 6-dichlorophenylindophenol (DCIP), 9-dimethylaminobenzo[alpha]phenoxazin-7-ium chloride (meldola's blue), 3,3'-[3,3'-dimethoxy-(1,1'-biphenyl)-4, 4'-diyl]-bis[2-(4-nitrophenyl)-5-phenyl-2H tetrazolium chloride] (nitroblue tetrazolium; NBT), and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H tetrazolium (INT). The presence of NAD(P) and oxygen gave no oxidation activity to GLDH. Spectroscopic profile and ICP data indicated a b-type cytochrome containing iron.

Aeromonas↗
PubMed1999

Human temporal bone study on the postnatal ossification process of auditory ossicles.

OBJECTIVE: In infancy the head of the malleus and body of the incus normally contain bone marrow, which is gradually replaced by bone and converted into vascular channels with age. This study was carried out to clarify the age at which ossification of the ossicles is complete and to examine factors influencing the ossification process. STUDY DESIGN: Human temporal bone sections from 32 infants and children with or without congenital anomalies, aged 1 day to 9 years, who were born at term were studied. METHODS: The percentage bone marrow area occupying the head of the malleus and body of the incus was calculated in three horizontal temporal bone sections for each case, using computer-aided digital processing of images. RESULTS: Bone marrow was observed in both the malleus and incus in children until 25 months of age, while after the age of 25 months no bone marrow tissue was present in either of the ossicles. It appeared that the bone marrow space disappeared somewhat earlier in the malleus than in the incus. The bone marrow space around the otic capsule disappeared much earlier than that within the ossicles. The age at completion of ossification was correlated with neither the presence of congenital anomalies nor the presence of residual mesenchyme in the middle ear. CONCLUSIONS: Ossification of the ossicles seems to occur steadily throughout fetal life and after birth during development of the middle ear. Although the clinical significance of postnatal residual bone marrow within the ossicles is not known, it possibly plays a role as a blood-forming organ in early infancy.

Bone Marrow↗
PubMed1999

Localization of precise origin of idiopathic ventricular tachycardia from the right ventricular outflow tract by a 12-lead ECG: a study of pace mapping using a multielectrode "basket" catheter.

Radiofrequency catheter ablation guided by pace-mapping techniques has proven effective in eliminating idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). A method for rapidly identifying the origin of VT from 12-lead electrocardiogram (ECG) findings would be helpful for the catheter ablation procedure. The purpose of this study is to precisely localize the origin of idiopathic VT from the RVOT by a 12-lead ECG from a study of multipoint pace mapping. In one patient with premature ventricular complex (PVC) and 3 with VT, a "basket" catheter was deployed in the RVOT for bipolar pacing from 56 sites in the endocardium of RVOT. Under fluoroscopy the pacing sites were classified into the septum and free wall. We investigated the QRS morphology in leads, I, II, and III; the depth of the QS wave in leads aVR and aVL; and the height of the initial r wave in leads V1 and V2. Pacing was captured in 30-47 of 56 sites (54%-84%). As the pacing sites changed from the anterior to posterior of the septum, the QS notch (-) type in lead I shifted through rs to R, while a shift from R type to rR' or Rr' was noted in leads II and III. As the pacing sites changed from the anterior to posterior of the free wall, lead I showed a shift from the QS notch (+) type to R, while a shift from rR' to Rr' (or rR' unchanged) was found in leads II and III. The depth of the QS wave in leads aVR and aVL showed a tendency for aVR to be deeper than aVL toward the posterolateral attachment of both the septum and free wall, whereas aVL tended to be deeper than aVR toward the anterior attachment. The initial r waves in V1 and V2 became greater as the pacing site was positioned at a higher or more posterior location. These findings may provide more precise and clinically useful diagnostic information on the site of the origin of idiopathic VT originating from the RVOT by a 12-lead ECG.

Adult↗
PubMed1999

Serum levels of soluble tumor necrosis factor receptors and effects of interferon therapy in patients with chronic hepatitis C virus infection.

OBJECTIVE: The aim of this study was to understand the significance of the tumor necrosis factor receptor (TNFR)-mediated signaling pathway in the pathophysiology of chronic hepatitis C. METHODS: The serum levels of soluble TNFRs (sTNFRs; sTNFR p55 and sTNFR p75) were measured in 84 patients with chronic hepatitis C virus (HCV) infection (24 sustained responders and 25 nonresponders to interferon [IFN] therapy and 35 patients with persistent normal blood chemistries) and 20 healthy controls, then compared with clinical parameters. RESULTS: The serum levels of sTNFRs increased in proportion to the severity of liver disease. The levels of sTNFRs revealed significant correlations with the serum levels of alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, and gamma-globulin, but not with the serum levels of HCV-core protein. In the sustained responder group, the levels of sTNFR p75 showed a significant decrease (p < 0.0002) 1 yr after IFN therapy, although the levels of sTNFR p55 did not. The levels of sTNFR p75 were correlated with the serum levels of macrophage-colony stimulating factor both before and after IFN therapy. In the nonresponder group, the levels of both sTNFRs were unaltered after IFN therapy. CONCLUSIONS: The TNF alpha-TNFRs system, especially the TNFR p75-mediated pathway, is involved in the hepatic inflammation-fibrosis process in chronic hepatitis C. The serum levels of sTNFR p75, but not sTNFR p55, were correlated with the serum levels of macrophage colony stimulating factor in this process.

Adult↗
PubMed1999

Phytate and phosphorus movements in the digestive tract of horses.

This experiment was conducted to study phytate degradation and the effect of dietary phytate level on phosphorus absorption in the gastrointestinal tract of horses. Six Thoroughbred horses were fed diets containing low-phytate diet or high-phytate diet for 5 days. The diets were supplemented with Cr2O3 as an unabsorbable marker. The horses were killed 3 h after the last feeding and digesta in some segments of the intestine were collected. In both dietary groups, the daily passage of phytate phosphorus was decreased in the upper small intestine and in the lower large intestine. The daily passage of phytate phosphorus in the lower large intestine did not differ between these groups. Although the passage of total phosphorus increased in the upper small intestine and in the upper large intestine of both groups, its passage decreased in the lower large intestine. These results suggest that phytate phosphorus is degraded in the upper small intestine and in the lower large intestine of both groups. Phosphorus is suggested to be mainly absorbed in the lower large intestine. Therefore, phytate phosphorus is considered to be easily absorbed in horses because the major site of phosphorus is the lower large intestine where most of phytate is already degraded.

Animal Feed↗
PubMed1999

Mapping the genetic determinants of pathogenicity and plaque phenotype in swine vesicular disease virus.

A series of recombinant viruses were constructed using infectious cDNA clones of the virulent J1'73 (large plaque phenotype) and the avirulent H/3'76 (small plaque phenotype) strains of swine vesicular disease virus to identify the genetic determinants of pathogenicity and plaque phenotype. Both traits could be mapped to the region between nucleotides (nt) 2233 and 3368 corresponding to the C terminus of VP3, the whole of VP1, and the N terminus of 2A. In this region, there are eight nucleotide differences leading to amino acid changes between the J1'73 and the H/3'76 strains. Site-directed mutagenesis of individual nucleotides from the virulent to the avirulent genotype and vice versa indicated that A at nt 2832, encoding glycine at VP1-132, and G at nt 3355, encoding arginine at 2APRO-20, correlated with a large-plaque phenotype and virulence in pigs, irrespective of the origin of the remainder of the genome. Of these two sites, 2APRO-20 appeared to be the dominant determinant for the large-plaque phenotype but further studies are required to elucidate their relative importance for virulence in pigs.

Animals↗
PubMed1999

ATP-Dependent inactivation and sequestration of ornithine decarboxylase by the 26S proteasome are prerequisites for degradation.

The 26S proteasome is a eukaryotic ATP-dependent protease, but the molecular basis of its energy requirement is largely unknown. Ornithine decarboxylase (ODC) is the only known enzyme to be degraded by the 26S proteasome without ubiquitinylation. We report here that the 26S proteasome is responsible for the irreversible inactivation coupled to sequestration of ODC, a process requiring ATP and antizyme (AZ) but not proteolytic activity. Neither the 20S proteasome (catalytic core) nor PA700 (the regulatory complex) by itself contributed to this ODC inactivation. Analysis with a C-terminal mutant ODC revealed that the 26S proteasome recognizes the C-terminal degradation signal of ODC exposed by attachment of AZ, and subsequent ATP-dependent sequestration of ODC in the 26S proteasome causes irreversible inactivation, possibly unfolding, of ODC and dissociation of AZ. These processes may be linked to the translocation of ODC into the 20S proteasomal inner cavity, centralized within the 26S proteasome, for degradation.

Adenosine Triphosphate↗
PubMed1999

Context-dependent modulation of replication activity of Saccharomyces cerevisiae autonomously replicating sequences by transcription factors.

Evidence for transcription factor involvement in the initiation of DNA replication at certain replication origins in Saccharomyces cerevisiae mainly comes from an indirect assay which measures the mitotic stability of plasmids containing an autonomously replicating sequence (ARS), a selectable marker gene, and a centromere. In order to eliminate the effect of transcription factor binding to the selectable marker gene or centromere in such assays, we have adapted the DpnI assay to directly measure ARS replication activity in vivo by using ARS plasmids devoid of extraneous transcription elements. Using this assay, we found that the B3 element of ARS1, which serves as a binding site for the transcription factor Abf1p, does not stimulate ARS activity on plasmids lacking a centromere and a selectable marker gene. We also found with such plasmids that exogenous expression of the strong transcriptional activators Gal4 and Gal4-VP16 inhibited the replication activity of ARS1 when B3 was replaced by the Gal4 binding site, although these activators had previously been shown to stimulate replication activity in the stability assay. Moreover, a chromosomally inactive ARS, ARS301, which was active by itself on a plasmid, was inactivated by placing an Abf1p binding site in its vicinity. These results indicate that the sequences surrounding the ARS as well as properties of the ARS element itself determine its response to transcription factors.

Binding Sites↗
PubMed1999

Characterization of a fission yeast SUMO-1 homologue, pmt3p, required for multiple nuclear events, including the control of telomere length and chromosome segregation.

Unlike ubiquitin, the ubiquitin-like protein modifier SUMO-1 and its budding yeast homologue Smt3p have been shown to be more important for posttranslational protein modification than for protein degradation. Here we describe the identification of the SUMO-1 homologue of fission yeast, which we show to be required for a number of nuclear events including the control of telomere length and chromosome segregation. A disruption of the pmt3(+) gene, the Schizosaccharomyces pombe homologue of SMT3, was not lethal, but mutant cells carrying the disrupted gene grew more slowly. The pmt3Delta cells showed various phenotypes such as aberrant mitosis, sensitivity to various reagents, and high-frequency loss of minichromosomes. Interestingly, we found that pmt3(+) is required for telomere length maintenance. Loss of Pmt3p function caused a striking increase in telomere length. When Pmt3p synthesis was restored, the telomeres became gradually shorter. This is the first demonstration of involvement of one of the Smt3p/SUMO-1 family proteins in telomere length maintenance. Fusion of Pmt3p to green fluorescent protein (GFP) showed that Pmt3p was predominantly localized as intense spots in the nucleus. One of the spots was shown to correspond to the spindle pole body (SPB). During prometaphase- and metaphase, the bright GFP signals at the SPB disappeared. These observations suggest that Pmt3p is required for kinetochore and/or SPB functions involved in chromosome segregation. The multiple functions of Pmt3p described here suggest that several nuclear proteins are regulated by Pmt3p conjugation.

Amino Acid Sequence↗
PubMed1999

Myocardial creatine kinase kinetics in hearts with postinfarction left ventricular remodeling.

This study examined whether alterations in myocardial creatine kinase (CK) kinetics and high-energy phosphate (HEP) levels occur in postinfarction left ventricular remodeling (LVR). Myocardial HEP and CK kinetics were examined in 19 pigs 6 wk after myocardial infarction was produced by left circumflex coronary artery ligation, and the results were compared with those from 9 normal pigs. Blood flow (microspheres), oxygen consumption (MVO2), HEP levels [31P magnetic resonance spectroscopy (MRS)], and CK kinetics (31P MRS) were measured in myocardium remote from the infarct under basal conditions and during dobutamine infusion (20 micrograms. kg-1. min-1 iv). Six of the pigs with LVR had overt congestive heart failure (CHF) at the time of study. Under basal conditions, creatine phosphate (CrP)-to-ATP ratios were lower in all transmural layers of hearts with CHF and in the subendocardium of LVR hearts than in normal hearts (P < 0.05). Myocardial ATP (biopsy) was significantly decreased in hearts with CHF. The CK forward rate constant was lower (P < 0.05) in the CHF group (0.21 +/- 0.03 s-1) than in LVR (0.38 +/- 0.04 s-1) or normal groups (0.41 +/- 0.03 s-1); CK forward flux rates in CHF, LVR, and normal groups were 6.4 +/- 2.3, 14.3 +/- 2.1, and 20.3 +/- 2.4 micromol. g-1. s-1, respectively (P < 0.05, CHF vs. LVR and LVR vs. normal). Dobutamine caused doubling of the rate-pressure product in the LVR and normal groups, whereas CHF hearts failed to respond to dobutamine. CK flux rates did not change during dobutamine in any group. The ratios of CK flux to ATP synthesis (from MVO2) under baseline conditions were 10.9 +/- 1.2, 8. 03 +/- 0.9, and 3.86 +/- 0.5 for normal, LVR, and CHF hearts, respectively (each P < 0.05); during dobutamine, this ratio decreased to 3.73 +/- 0.5, 2.58 +/- 0.4, and 2.78 +/- 0.5, respectively (P = not significant among groups). These data demonstrate that CK flux rates are decreased in hearts with postinfarction LVR, but this change does not limit the response to dobutamine. In hearts with end-stage CHF, the changes in HEP and CK flux are more marked. These changes could contribute to the decreased responsiveness of these hearts to dobutamine.

Animals↗
PubMed1999

Oxygen delivery does not limit cardiac performance during high work states.

This study tested the hypothesis that the loss of myocardial high-energy phosphates (HEP), which occurs during high cardiac work states [J. Zhang, D. J. Duncker, Y. Xu, Y. Zhang, G. Path, H. Merkle, K. Hendrich, A. H. L. From, R. Bache, and K. Uğurbil. Am. J. Physiol. 268: (Heart Circ. Physiol. 37): H1891-H1905, 1995], is not the result of insufficient intracellular O(2) availability. To evaluate the state of myocardial oxygenation, the proximal histidine signal of deoxymyoglobin (Mb-delta) was determined with (1)H nuclear magnetic resonance spectroscopy (MRS), whereas HEP were examined with (31)P MRS. Normal dogs (n = 11) were studied under basal conditions and during combined infusion of dobutamine and dopamine (20 micrograms . kg(-1). min(-1) iv each), which increased rate-pressure products to >50,000 mmHg. beats. min(-1). Creatine phosphate (CP) was expressed as CP/ATP, and myocardial myoglobin desaturation was normalized to the Mb-delta resonance present during total coronary artery occlusion. This Mb-delta resonance appeared at 71 parts per million downfield from the water resonance. CP/ATP decreased from 2. 22 +/- 0.12 during the basal state to 1.83 +/- 0.09 during the high work state (P < 0.01), whereas DeltaP(i)/CP increased from 0 to 0.21 +/- 0.04 (P < 0.01). Despite these HEP changes, Mb-delta remained undetectable. In contrast, when a coronary stenosis was applied to produce a similar decrease in CP/ATP, Mb-delta reached 0.38 +/- 0.10 of the value present during total coronary occlusion. These data demonstrate that Mb-delta is readily detected in vivo during limitation of coronary blood flow sufficient to cause a decrease of myocardial CP/ATP. However, similar HEP changes that occur at high work states in the absence of coronary occlusion are not associated with a detectable Mb-delta resonance. The findings support the hypothesis that the myocardial HEP changes observed at high work states are not due to inadequate O(2) availability to the mitochondria and emphasize the limitations of interpreting HEP alterations in the absence of knowing the level of myocyte oxygenation.

Animals↗
PubMed1999

Anticonvulsant activity of paeonimetabolin-I adducts obtained by incubation of paeoniflorin and thiol compounds with Lactobacillus brevis.

Seventeen thiopaeonimetabolin-I adducts were obtained as mixtures of diastereoisomers after incubation of paeoniflorin with Lactobacillus brevis in the presence of various thiols. The anticonvulsant activity of the adducts was investigated in mice using the maximal subcutaneous pentylenetetrazol seizure test and sodium valproate (1.5 mmol/kg) as a positive control. Thirteen adducts showed dose-dependent prolongation of latencies of clonic and tonic convulsions. Maximal protection against convulsions was effectively demonstrated by 8-(n-hexylthio)paeonimetabolin I (8) and 8-benzoylthiopaeonimetabolin I (18) at doses of 0.125 and 0.25 mmol/kg, respectively, while 100% protection was only achieved at 0.5 mmol/kg of 8-cyclopentylthiopaeonimetabolin I and 8-(p-tolylthio)paeonimetabolin I. The principal anticonvulsant activity of the diastereoisomers of 8 and 18 was attributed to their 7S-isomers [ED50 values of 0.09 and 0.12 mmol/kg, and protective indices of 5.0 and 4.0 for 8 (7S) and 18 (7S), respectively], while the 7R counterparts [8 (7R) and 18 (7R)] showed a muscle relaxation effect.

Analysis of Variance↗
PubMed1999

[Chemistry of indoles: new reactivities of indole nucleus and its synthetic application].

This review summarizes our studies on the development of new reactivities of the indole nucleus and on its application for the synthesis. These studies involve the following five main subjects: 1) The Vilsmeier-Haack reaction was applied to 1,2,3,4-tetrahydrocarbazole and its N-alkyl compounds. The conditions and the mechanisms of the formation of three kinds of products obtained from the latter compound were clarified, and among the three products, 1,9-dimethylcarbazole-3-aldehyde was found to be useful for the syntheses of olivacine and ellipticine. 2) The Fischer indole synthesis of various 2-substituted phenylhydrazones was examined in detail and it was found that the Fischer indole synthesis of 2-sulfonyloxyphenylhydrazones served a new and convenient method for the synthesis of 7-oxygenated indoles. This reaction was applied to the synthesis of eudistomidin-A. 3) The reactivities of ethyl indole-2-carboxylate for acylation and bromination were also studied, and the use of this compound as a starting material for the synthesis of 4-methoxy-beta-carbolines was successfully investigated. 4) Acylation of ethyl pyrrole-2-carboxylate was concisely studied and this reaction was applied to the syntheses of benzene ring-substituted indoles and benz[f]indoles involving eupolauramine. 5) Two kinds of method for the debenzylation of N-benzylindoles were developed using either AlCl3-benzene or methyl lithium, and they are complementary with each other.

Chemistry, Organic↗