Biomedical subjects

T Nakano

Publications and source records attributed to T Nakano.

At least 325 records · Page 18Linked to original sources

PubMed1999

Rho-associated kinase of chicken gizzard smooth muscle.

Rho-associated kinase (Rho-kinase) from chicken gizzard smooth muscle was purified to apparent homogeneity (160 kDa on SDS-polyacrylamide gel electrophoresis) and identified as the ROKalpha isoform. Several substrates were phosphorylated. Rates with myosin phosphatase target subunit 1 (MYPT1), myosin, and the 20-kDa myosin light chain were higher than other substrates. Thiophosphorylation of MYPT1 inhibited myosin phosphatase activity. Phosphorylation of myosin at serine 19 increased actin-activated Mg+-ATPase activity, i.e. similar to myosin light chain kinase. Myosin phosphorylation was increased at higher ionic strengths, possibly by formation of 6 S myosin. Phosphorylation of the isolated light chain and myosin phosphatase was decreased by increasing ionic strength. Rho-kinase was stimulated 1.5-2-fold by guanosine 5'-O-3-(thio)triphosphate.RhoA, whereas limited tryptic hydrolysis caused a 5-6-fold activation, independent of RhoA. Several kinase inhibitors were screened and most effective were Y-27632, staurosporine, and H-89. Several lipids caused slight activation of Rho-kinase, but arachidonic acid (30-50 microM) induced a 5-6-fold activation, independent of RhoA. These results suggest that Rho-kinase of smooth muscle may be involved in the contractile process via phosphorylation of MYPT1 and myosin. Activation by arachidonic acid presents a possible regulatory mechanism for Rho-kinase.

Amino Acid Sequence↗

PubMed1999

Suppression of agglomeration in fluidized bed coating. II. Measurement of mist size in a fluidized bed chamber and effect of sodium chloride addition on mist size.

It has been reported that the degree of particle agglomeration in fluidized bed coating is greatly affected by the spray mist size of coating solution. However, the mist size has generally been measured in open air, and few reports have described the measurement of the mist size in a chamber of the fluidized bed, in which actual coating is carried out. Therefore, using hydroxypropylmethyl cellulose (HPMC) aqueous solution as a coating solution, the spray mist size of the coating solution in a chamber of the fluidized bed was measured under various coating conditions, such as the distance from the spray nozzle, fluidization air volume, inlet air temperature and addition of sodium chloride (NaCl) into the coating solution. The mist size in the fluidized bed was compared with that in open air at various distances from the spray nozzle. Further, the relationship between the spray mist size and the degree of suppression of agglomeration at various NaCl concentrations during fluidized bed coating was studied. The mist size distribution showed a logarithmic normal distribution in both cases of the fluidized bed and open air. The number-basis median diameter of spray mist (D50) in the fluidized bed was smaller compared with that in open air. D50 increased with the increasing distance from the spray nozzle in both cases. In the fluidized bed, D50 decreased with the increasing fluidization air volume and inlet air temperature. The effect of NaCl concentration on the mist size was hardly observed, but the degree of suppression of agglomeration during coating increased with the increasing NaCl concentration in the coating solution.

Chemistry, Pharmaceutical↗

PubMed1999

Induction of germinal vesicle breakdown in a cell-free preparation from starfish oocytes.

Incubation of isolated germinal vesicles in the homogenate from maturing starfish oocytes resulted in synchronous germinal vesicle breakdown (GVBD), and chromosome condensation and gathering within 30 min. GVBD in this cell-free system required aerobic conditions. The endogenous ATP-generation system was preserved in the homogenate and effective under aerobic conditions, and thus exogenous ATP was not added to the homogenate. Injection of the homogenate into immature starfish oocytes induced meiotic maturation without 1-methyladenine, indicating high activity of maturation-promoting factor (MPF) in the homogenate. MPF activity in the homogenate was stable for 2 h at room temperature, while it disappeared within 1 h in the supernatant prepared by centrifugation of the homogenate. This disappearance of MPF activity is regulated by cyclin B destruction, similar to that seen in vivo.

Animals↗

PubMed1999

Characterization of the bleomycin resistance determinant encoded on the transposon Tn5.

The transposon Tn5 carries a gene, ble, which confers resistance to bleomycin (Bm) and gives a survival advantage to its host cell. We found that the ble gene product, designated BLMT, is a binding protein with a strong affinity for Bm. BLMT quenched both the antibacterial and DNA-cleaving activities of Bm, when incubated with the antibiotic. An electron spin resonance spin-trapping analysis showed that BLMT inhibits the generation of Bm-induced hydroxyl radical, by trapping Bm but not the hydroxyl radical. Western blot analysis using an anti-BLMT monoclonal antibody revealed that BLMT is immunologically distinct from Bm-binding proteins from Streptomyces verticillus, Staphylococcus aureus and Streptoalloteichus hindustanus. Escherichia coli, transformed with a mutant ble having leucine instead of proline at N-terminal amino acid position 7, lost resistance to Bm, although the cell maintained the survival benefit. This suggests that the Bm resistance mediated by ble is independent of its ability to give a survival advantage to the host bacterium.

Acetyltransferases↗

PubMed1999

Effect of astaxanthin rich red yeast (Phaffia rhodozyma) on oxidative stress in rainbow trout.

The antioxidative biological effect of dietary red yeast, Phaffia rhodozyma, which is rich in astaxanthin, on rainbow trout, Oncorhynchus mykiss, was examined. The levels of serum transaminase (glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase) activities and of lipid peroxides (LPO) of fish fed oxidized oil were significantly higher than those of the control fish fed non-oxidized oil. However, the supply of red yeast considerably decreased both enzyme activities and LPO level. Furthermore, the serum lipid (triglycerides, total cholesterol and phospholipids) concentrations were also significantly decreased. Especially, the serum triglyceride level of fish fed the red yeast was as low as that of the control. It was also observed that there were no significant differences in muscle LPO levels between the fish fed red yeast and the control. The present results suggest for the first time that dietary red yeast may effectively suppress the LPO generation of tissue and normalize liver function as well as improving muscle pigmentation of trout. Thus, red yeast should have a reducing effect on oxidized oil-induced oxidative stress in fish.

Animal Feed↗

PubMed1999

Immunosuppressive activities of recombinant glycosylation-inhibiting factor mutants.

We have shown previously that glycosylation-inhibiting factor (GIF) in culture supernatants of suppressor T cell (Ts) hybridomas had bioactivity, while the same cells contained a substantial quantity of inactive GIF in cytosol. Mass-spectrometric analysis of GIF in the culture supernatant and cytosol of a Ts hybridoma provided direct evidence that GIF protein was posttranslationally modified in the Ts cells, and that the GIF bioactivity is associated with the posttranslationally modified species. Assuming that conformational changes induced by the posttranslational modifications are responsible for generation of bioactivity, we constructed cysteine mutants of human rGIF (rhGIF) in which cysteine at position 57, 60, or 81 was replaced with Ala, and the mutants were expressed in Escherichia coli. Replacement of Cys57 or Cys60 with Ala resulted in generation of bioactivity, while replacement of Cys81 with Ala failed to do so. It was also found that replacement of Cys57 with Ala and carboxymethylation of a sulfhydryl group in Cys60 synergistically increased the GIF bioactivity of the GIF derivatives. A mutated GIF protein, in which Cys57 and Asn106 in the rhGIF were replaced with Ala and Ser, respectively, had immunosuppressive effects on the IgE and IgG1 Ab responses of BDF1 mice to DNP-OVA, while wild-type rhGIF did not. Evidence was obtained that the mutated GIF suppressed Ag priming of Th cells for the Ab responses and proliferative response.

Animals↗

PubMed1999

Changes of plasma hemostatic markers during percutaneous transluminal coronary angioplasty in patients with chronic coronary artery disease.

Changes of hemostatic parameters during percutaneous transluminal coronary angioplasty (PTCA) in 75 patients with chronic coronary artery disease were evaluated. Plasma levels of D-dimer, soluble fibrin monomer, plasmin-alpha2 antiplasmin inhibitor complex, and tissue factor (TF) were significantly increased in all patients with chronic coronary artery disease. The activity of antithrombin and protein C and the levels of protein C antigen were significantly decreased 1 hr after PTCA, but they returned to normal range 1 day after PTCA. There was no significant difference in the level of plasma APC-PCI complex before and 1 hr after PTCA. The plasma levels of D-dimer, soluble fibrin monomer, thrombomodulin, TF and PPIC were significantly decreased 1 hr, and the plasma levels of plasmin-alpha2 antiplasmin inhibitor complex 1 day after PTCA. These findings suggest that the decrease of protein C and antithrombin resulted in activation of the coagulation system. One hour after PTCA, the plasma levels of (total-free) TF pathway inhibitor (TFPI) were significantly decreased, but the plasma levels of total and free-TFPI were significantly increased, suggesting that consumption of (total-free) TFPI occurs during PTCA. Overall, these findings suggest that the hypercoagulable state improves during PTCA and that transient decrease of antithrombin, protein C, (total-free) TFPI or plasmin-alpha2 antiplasmin inhibitor complex may cause restenosis of coronary artery.

Angioplasty, Balloon, Coronary↗

PubMed1999

A new genotype of TT virus (TTV) infection among Colombian native Indians.

Serum TTV DNA was assayed in 140 native Indians and 40 members of the general population in Colombia to determine the prevalence of TT virus (TTV) infection among Colombian native Indians. Of the 140 native Indians, 23 (16.4%) were positive for TTV DNA, compared to 4 (10.0%) of 40 from the general population (P = not significant). The prevalence of TTV DNA among native Indians was much higher than that of HBsAg and anti-HCV. Comparison of subjects with and without TTV DNA revealed no significant differences in all characteristics between the two groups. A phylogenetic tree, using the open reading frame 1 sequence (222 bp), indicated that the virus could be classified into four different genotypes, including three previously reported ones. The results show that TTV infection is common in Colombian native Indians without liver disease and also indicate the existence of a novel genotype of TTV.

Adolescent↗

PubMed1999

Amino acid substitutions in NS5A region of GB virus C and response to interferon therapy.

GB virus C (GBV-C) is related to hepatitis C virus (HCV) and has a similar genomic structure. Some predictors for the efficacy of interferon (IFN) therapy on HCV have been reported: genotype, viral load, IFN dose, and the amino acid substitutions in the NS5A region, designated as the interferon sensitivity determining region (ISDR). To evaluate the correlation between the amino acid substitutions in the GBV-C NS5A region and the response to IFN therapy, single-strand conformation polymorphism (SSCP) analysis was performed in the 12 concomitantly GBV-C-and HCV-infected patients who received IFN therapy at three time points: before, end-point, and after the IFN therapy. The region in the GBV-C NS5A studied includes the amino acids that exhibit some homology to the ISDR and the various substitutions. By SSCP analysis, amplicons were separated into 1-4 bands, which indicated the existence of heterogeneity in each host. However, the deduced amino acid sequences in these bands exhibited no characteristic differences among these strains irrespective of response to IFN therapy. Of the 32 strains separated by SSCP, 7 strains were responders, and 25 were nonresponders. The mean amino acid substitution, compared with the consensus sequence of nonresponders, was 1.00+/-0.93 among responders, and 1.40+/-0.85 among non-responders (P= NS). No correlation between the amino acid sequence in the GBV-C NS5A region and response to IFN therapy was found, indicating that the GBV-C NS5A region dose not act as the ISDR.

Adult↗

PubMed1999

Assessment of coronary flow reserve with fast cine phase contrast magnetic resonance imaging: comparison with measurement by Doppler guide wire.

Fast cine phase contrast magnetic resonance imaging (fast cine phase contrast MRI) can measure phasic coronary flow velocity in humans. The purpose of this study was to compare the coronary flow velocity reserves measured by MR IMAGING with those obtained by Doppler guide wire. Nineteen patients with ischemic or valvular heart disease were studied. Fast cine phase contrast MR images of the left anterior descending (LAD) artery were acquired during breath-hold time in the basal state and after administration of dipyridamole. Flow velocity in the LAD artery was also measured with Doppler guide wire before and after venous injection of dipyridamole in all subjects. Flow velocity in the coronary artery measured with MR IMAGING in the basal state (12.5 +/- 4.9 cm/sec) was significantly lower than that obtained with Doppler guide wire (32.4 +/- 12.1 cm/sec, P < 0.01). However, MR assessments of coronary flow velocity reserve showed a good linear correlation with those measured by Doppler guide wire (r = 0.91). In conclusion, fast cine phase contrast MR imaging is a useful technique, which can provide a noninvasive assessment of flow reserve ratios in patients with coronary artery disease. J. Magn. Reson. Imaging 1999;10:563-568.

Blood Flow Velocity↗

PubMed1999

Expression of functional CD40 in human hepatocellular carcinoma.

CD40, a member of the tumor necrosis factor receptor (TNFR) family, plays a crucial role in the survival, proliferation, and differentiation in B cells. However, the expression of CD40 other than in B cells has not been well studied. Therefore, we investigated the expression and function of CD40 in hepatocellular carcinomas (HCCs). Expression of CD40 mRNA in 6 established HCC cell lines was analyzed by reverse-transcription polymerase chain reaction (RT-PCR) and CD40 expression on cell surface was examined by flow cytometrical analysis. We also examined the expression of CD40 in human HCC tissues (45 cases) and nontumor liver tissues (30 cases) by immunohistochemistry. To examine the function of CD40 in HCC cells, we investigated the effect of CD40 signaling on anti-Fas antibody and TNF-alpha-induced apoptosis in HepG2 cells. In addition, intracellular levels of cysteine protease P32 (CPP32) protein in HepG2 cells were also determined by Western blotting. We have shown that 6 HCC cell lines constitutively expressed CD40 mRNA and membrane-bound CD40 antigen, which was slightly up-regulated by interferon gamma (IFN-gamma). In addition, 60% of human HCC tissues demonstrated positive staining for CD40, whereas nontumor tissues showed little detectable staining. In HepG2 cells, CD40 stimulation does not affect cell viability, but significantly inhibited Fas and TNFR-mediated apoptosis in a dose-dependent manner by blocking the activation of CPP32. From these results, we conclude that CD40 expression in HCCs plays an important role in tumor biology, especially the resistance against Fas and TNFR-mediated apoptosis.

Apoptosis↗

PubMed1999

Phylogeny of organisms investigated by the base-pair changes in the stem regions of small and large ribosomal subunit RNAs.

In order to obtain the evolutionary distance data that are as purely additive as possible, we have developed a novel method for evaluating the evolutionary distances from the base-pair changes in stem regions of ribosomal RNAs (rRNAs). The application of this method to small-subunit (SSU) and large-subunit (LSU) rRNAs provides the distance data, with which both the unweighted pair group method of analysis and the neighbor-joining method give almost the same tree topology of most organisms except for some Protoctista, thermophilic bacteria, parasitic organisms, and endosymbionts. Although the evolutionary distances calculated with LSU rRNAs are somewhat longer than those with SSU rRNAs, the difference, probably due to a slight difference in functional constraint, is substantially decreased when the distances are converted into the divergence times of organisms by the measure of the time scale estimated in each type of rRNAs. The divergence times of main branches agree fairly well with the geological record of organisms, at least after the appearance of oxygen-releasing photosynthesis, although the divergence times of Eukaryota, Archaebacteria, and Eubacteria are somewhat overestimated in comparison with the geological record of Earth formation. This result is explained by considering that the mutation rate is determined by the accumulation of misrepairs for DNA damage caused by radiation and that the effect of radiation had been stronger before the oxygen molecules became abundant in the atmosphere of the Earth.

Algorithms↗

PubMed1999

Successful antidepressant treatment for five terminally ill cancer patients with major depression, suicidal ideation and a desire for death.

In the debate on euthanasia and physician-assisted suicide, we have to exclude terminally ill patients in whom the desire for death is caused by major depression. However, it is still not clear to what degree major depression can be treated by psychiatric intervention in this setting. We evaluated the effect of antidepressant treatment in terminally ill cancer patients. Six cancer patients with suicidal ideas thought to be due to major depression were treated with tricyclic antidepressants. Three had requested terminal sedation to relieve them from their suffering. The median survival of five of these patients was 4 weeks after diagnosis; one was lost to follow-up. The efficacy of the antidepressant treatment was assessed using the Hamilton Rating Scale for Depression (HRSD). One week after the start of treatment with antidepressants, five of the six patients showed a marked improvement in their mood and showed no further suicidal thoughts or requests for terminal sedation. The average reduction in the HRSD score was 23.4 points (14-38; SD = 9. 9). Antidepressant treatment can be effective in alleviating the desire for death due to major depression, even in terminally ill cancer patients.

Affect↗

PubMed1999

Association of plasma triglyceride-rich lipoprotein remnants with coronary atherosclerosis in cases of sudden cardiac death.

Among the risk factors for coronary atherosclerosis, elevated LDL-C level is best known. The action of lipoprotein lipase on triglyceride-rich lipoproteins produces remnant lipoprotein particles enriched in cholesterol and apolipoprotein E (apo E). Apo E serves as the ligand for uptake of remnant lipoproteins via the LDL-receptor or the remnant receptor. In this study, postmortem plasma total cholesterol, triglycerides (TG), VLDL-C, HDL-C, lipoprotein (a) [Lp(a)] and remnant-like lipoprotein particles (RLP)-cholesterol, RLP-TG, apolipoproteins B, C III and E were measured, together with LDL-C to assess their potential contribution to the severity of coronary and aortic atherosclerosis of the 197 cases of sudden death (132 cardiac death and 65 non-cardiac death). In all cases, the severity of coronary atherosclerosis was determined at postmortem pathological examination. RLP-cholesterol (RLP-C) and LDL-C concentrations were significantly higher in cases with advanced coronary atherosclerosis compared with those without coronary atherosclerosis; respective median values were 13.5 vs 8.4 mg/dl (P < 0.001) and 140 vs 115 mg/dl (P < 0.05). RLP-C levels were more strongly correlated with the severity score of coronary atherosclerosis than LDL-C.

Adult↗

PubMed1999

Effect of glucose on the plasma concentration and urinary excretion of uridine and purine bases.

To examine whether glucose increases the plasma concentration of purine bases and uridine, 75 g glucose was administered orally to eight healthy subjects and two patients with hyperuricemia. The plasma concentration of uridine increased by 21%, 25%, and 20% 30, 60, and 90 minutes after administration of glucose, respectively. However, urinary excretion of uridine was not affected, nor were the plasma concentrations and urinary excretion of purine bases (hypoxanthine, xanthine, and uric acid). These results suggest that the glucose-induced increase in plasma uridine was not concomitant with adenosine triphosphate (ATP) consumption-induced purine degradation, but instead was ascribable to a uridine diphosphate (UDP)-glucose consumption-induced pyrimidine degradation (UDP-glucose-->UDP-->uridine monophosphate [UMP]-->uridine).

Adult↗

PubMed1999

High prevalence and phylogenetic analysis of TT-virus infection in Mongolia.

A novel DNA virus, TT-virus (TTV), was isolated from a post-transfusion hepatitis patient in Japan. The prevalence of TTV infection was investigated among patients with chronic liver disease and normal alanine aminotransferase (ALT) volunteers as controls in Mongolia. Polymerase chain reaction (PCR) was employed to detect TTV DNA using specific primers derived from open reading frame 1 (ORF1) of the TTV genome. Nucleotide sequences of samples positive for TTV DNA were determined. The sequences were analyzed by a molecular evolutionary method. Fifty (60.2%) hepatitis patients and 12 (42.9%) volunteers were positive for TTV DNA. The serum ALT levels did not differ significantly between patients with single TTV infection and without TTV, HBV and HCV infection. Similarly, the serum ALT levels did not differ significantly between controls with and without TTV infection. Dual infection of TTV with either HBV or HCV did not affect the ALT levels of hepatitis patients. The molecular evolutionary tree showed that TTV was a heterogeneous virus and all strains could be divided into three genotypes in Mongolia. A new genotype was identified that was distinct from those previously reported.

Adult↗

PubMed1999

TT virus infection among blood donors and patients with non-B, non-C liver diseases in Korea.

BACKGROUND/AIMS: A novel virus, designated the TT virus (TTV), was isolated from the serum of a patient with posttransfusion hepatitis of unknown etiology, in Japan. Subsequently, TTV was suggested to be a causative agent in a proportion of cases with cryptogenic hepatitis in Japan. This study aimed to elucidate the significance of TTV infection in cases with cryptogenic liver disease in Korea, a neighbor of Japan. METHODS: The prevalence of TTV infection was studied in 120 patients with liver diseases, including 85 patients diagnosed as having non-B, non-C liver diseases. As controls, 220 blood donors were also examined. TTV DNA was detected by polymerase chain reaction, and the sequence was analyzed by phylogenetic analysis. RESULTS: Fourteen (14.0%) of 100 accepted blood donors, 23 (19.2%) of 120 rejected blood donors, and 15 (17.6%) of 85 patients with non-B, non-C liver diseases were positive for TTV DNA. The prevalences of TTV infection among these groups were not significantly different. Phylogenetic analysis suggested the existence of four major genotypes of TTV The proportions of each genotype among patients with non-B, non-C liver diseases were not different from those among accepted blood donors. CONCLUSIONS: TTV exists in Korea, but the prevalence among patients with non-B, non-C liver diseases was almost the same as that among blood donors. TTV may not be the main causative agent of cryptogenic liver disease in Korea. The relationship between non-B, non-C liver diseases and TTV genotype remains unclear, although TTV can be classified into four genotypes.

Adolescent↗

PubMed1999

High prevalance of TT virus infection in Japanese patients with liver diseases and in blood donors.

BACKGROUND/AIMS: Although a novel DNA virus, TT virus (TTV), has been isolated from a patient with cryptogenic post-transfusion hepatitis, its pathogenic role remains unclear. To elucidate its prevalence and clinical impact in patients with liver diseases, the presence of TTV DNA was assessed in patients with liver diseases and blood donors (BDs) in Japan using two primer sets, one conventional and the other new and highly sensitive. METHODS: We studied 261 samples, 72 with chronic hepatitis associated hepatitis C virus (HCV-CH), 57 with hepatocellular carcinoma associated HCV (HCV-HCC), 12 with HCC without either HCV or hepatitis B virus (NBNC-HCC), and 120 of BDs. RESULTS: Using two primer sets, TTV DNA was detected in 68 (94.4%), 53 (93.0%), 12 (100%), and 98 (81.7%) HCV-CH, HCV-HCC, NBNC-HCC, and BDs, respectively. The prevalence was not significantly different between HCV-CH and HCV-HCC, or between HCV-HCC and NBNC-HCC. Comparison between patients with and without TTV revealed no significant differences in backgrounds or biochemical findings. Histopathological findings in patients with HCV-CH, and number, maximum diameter, and histological differentiation of HCC also did not demonstrate any relation to TTV infection. TTV strains can be divided into five groups using phylogenetic analysis, but no disease-specific group appears to exist. CONCLUSIONS: Our data suggest that: 1) TTV is very prevalent among patients with liver diseases and even among BDs in Japan, 2) TTV infection does not impact on liver damage with HCV infection, and 3) TTV infection also does not affect the development or progression of HCC.

Adult↗