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Hiroyuki Nakamura

Publications and source records attributed to Hiroyuki Nakamura.

At least 55 records · Page 3Linked to original sources
PubMed2005

Reversible activation of secretory phospholipase A2 by sulfhydryl reagents.

Secretory phospholipase A(2)s (sPLA(2)s) have been implicated in physiological and pathological events, but the regulatory mechanism(s) of their activities in cells remains to be solved. Previously, we reported that phenylarsine oxide (PAO), a sulfhydryl reagent, stimulated arachidonic acid (AA) release in rat pheochromocytoma PC12 cells. In this study, we examined the effects of thimerosal, another sulfhydryl reagent, to clarify the sulfhydryl modification and activation of sPLA(2) molecules in cells. Like PAO, thimerosal-stimulated AA release in an irreversible manner and the responses were not additive. Dithiol compounds such as dithiothreitol inhibited AA release from both the thimerosal- and the PAO-treated cells, and monothiol compounds (l-Cys and glutathione) decreased the thimerosal response. Both sulfhydryl reagents stimulated AA release from the HEK293T cells expressing human sPLA(2)X, and stimulated the sPLA(2) activities of bee venom sPLA(2) and the soluble fraction of sPLA(2)X-expressing cells. Our results suggest that the sPLA(2)s in cells are inactive and modification of disulfide bonds in the molecules can be a trigger of sPLA(2) activation in cells. Sulfhydryl reagents are useful tools for studying the regulatory mechanism(s) of sPLA(2) activity in cells.

Animals↗
PubMed2005

Transforming growth factor-beta1 induces LMO7 while enhancing the invasiveness of rat ascites hepatoma cells.

We have previously shown that transforming growth factor-beta1 (TGF-beta1) markedly stimulates the invasive capacity of rat ascites hepatoma AH130 W1 cells in vitro and in vivo. A differential hybridization procedure was used to isolate genes that were specifically up-regulated in TGF-beta1 treated W1 cells. Among ten independent cDNA clones, we focused on LMO7 and a variant isoform, LMO7S, that was generated by alternative splicing. LMO7 had PDZ and LIM domains, while LMO7S had only PDZ domain. TGF-beta1 up-regulated expression levels of LMO7 and LMO7S. LMO7 expression was up-regulated in the highly metastatic clone MM1.

Animals↗
PubMed2005

Synthesis of heterocyclic allenes via palladium-catalyzed hydride-transfer reaction of propargylic amines.

[reaction: see text] Propargylic diisopropylamines containing heterocycles, which were prepared readily from heterocyclic bromides and propargyldiisopropylamine by the Sonogashira coupling reaction, underwent the allene transformation reaction in the presence of Pd(2)(dba)(3).CHCl(3) catalyst (2.5 mol %) and 1,2-bis[bis(pentafluorophenyl)phosphino]ethane (10 mol %) at 100 degrees C in CHCl(3), giving the corresponding heterocyclic allenes in good to high yields via the palladium-catalyzed hydride-transfer reaction.

Alkenes↗
PubMed2005

Increasing prevalence of Japanese cedar pollinosis: a meta-regression analysis.

BACKGROUND: Japanese cedar pollinosis, caused by the pollen of the Japanese cedar tree (Cryptomeria japonica), is the commonest seasonal allergic disease in Japan. A number of epidemiological surveys have been reported on Japanese cedar pollinosis, but it has never been assessed systematically or quantitatively. To confirm the increasing prevalence of Japanese cedar pollinosis and related factors, we conducted a meta-regression analysis on population-based surveys in Japan. METHODS: We searched for data from population-based surveys in which serological methods were used to test all participants. Weighted regression of logit-transformed prevalence and sensitization rates were used to evaluate the effects of the year of survey, age, and degree of urbanization. We also analyzed the relationship between prevalence and sensitization rate. RESULTS: Thirty-eight reports with 27 subgroups for prevalence and 134 subgroups for sensitization rate were selected from the literature published in the years between 1986 and 2000. The Japanese cedar pollen sensitization rate was found to be significantly correlated with the year of survey, age, and degree of urbanization (adjusted R(2) = 0.55). The coefficient for the correlation between the prevalence and the sensitization rate revealed a statistically significant correlation (Pearson's r = 0.70, p < 0.001). CONCLUSIONS: The prevalence of Japanese cedar pollinosis among adolescents was predicted to be 28.7% in metropolitan areas and 24.5% in the general population in urban areas in the year 2004, derived from the estimated sensitization rate and the relationship between sensitization rate and prevalence. The prevalence of Japanese cedar pollinosis increased 2.6-fold between 1980 and 2000, and the prevalence differed considerably according to age and degree of urbanization.

Adolescent↗
PubMed2005

Synthesis and in vivo biodistribution of BPA-Gd-DTPA complex as a potential MRI contrast carrier for neutron capture therapy.

p-boronophenylalanine (BPA) conjugated Gd-DTPA complex (3) was synthesized from the active methyne compound 6, the allylic carbonate 7, and BPA by the palladium-catalyzed allylation reaction followed by the DCC coupling reaction. The in vivo biodistribution of complex 3 was evaluated by prompt gamma-ray analysis and alpha-autoradiography using the tumor-bearing rats. High accumulation of gadolinium was observed in the kidney and the %ID values were 0.17 and 0.088 at 20 and 60 min after injection of 3, respectively. The accumulation was also observed in the tumor and the %ID values were 0.010 and 0.0025 at 20 and 60 min after injection, respectively. The visualization experiment of boron distribution in the tumor-bearing rat by alpha-autoradiography indicates that boron was accumulated in the tumor and the intestines at 20 min after injection.

Animals↗
PubMed2005

Detection of Helicobacter pylori in the middle ear fluid of patients with otitis media with effusion.

OBJECTIVES: In patients with otitis media with effusion (OME), colonization of the middle ear effusion (MEE) by Helicobacter pylori (HP) was investigated. STUDY DESIGN: A prospective nonrandomized study with nonpaired, nonmatched controls. Smear preparations were immunostained with anti-HP antibody and were subjected to Gram staining and Giemsa staining. The rapid urease test (CLO) was done. RESULTS: Twelve of 15 smears for MEE were positive for HP by immunohistochemistry and 14 by Giemsa that were Gram-negative. In 3 with positive immunohistochemistry, the CLO was positive. CONCLUSION: The results suggest that HP may exist in the MEE of some patients with OME.

Adolescent↗
PubMed2005

Eradication of Epstein-Barr virus episome and associated inhibition of infected tumor cell growth by adenovirus vector-mediated transduction of dominant-negative EBNA1.

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1), a latent viral protein consistently expressed in infected proliferating cells, is essentially required in trans to maintain EBV episomes in cells. We constructed a mutant (mt) EBNA1 and examined whether it exerted dominant-negative effects on maintenance of the viral episome thereby leading to abrogation of EBV-infected tumor cell growth. Using lymphocyte and epithelial cell lines converted with neomycin-resistant recombinant EBV (rEBV) as models, adenovirus vector-mediated transduction of mtEBNA1, but not LacZ, brought about rapid and striking reductions in rEBV-derived wild-type EBNA1 levels and viral genomic loads in converted lines of three major viral latencies. This outcome was further validated at the single-cell level by cellular loss of G418 resistance and viral signals in situ. The mtEBNA1 transduction significantly impaired growth of naturally EBV-harboring Burkitt lymphoma cells in vitro and in vivo, largely in association with the eradication of viral episomes. Expression of mtEBNA1 per se caused no detectable cytotoxicity in EBV-uninfected cells. These results indicate that mtEBNA1 can act as a dominant-negative effector that efficiently impedes the EBV-dependent malignant phenotypes in cells regardless of viral latency or tissue origin. The mutant will afford an additional therapeutic strategy specifically targeting EBV-associated malignancies.

Adenoviridae↗
PubMed2005

Epidermolysis bullosa simplex associated with pyloric atresia is a novel clinical subtype caused by mutations in the plectin gene (PLEC1).

Epidermolysis bullosa (EB) is an inherited mechano-bullous disorder of the skin, and is divided into three major categories: EB simplex (EBS), dystrophic EB, and junctional EB (JEB). Mutations in the plectin gene (PLEC1) cause EBS associated with muscular dystrophy, whereas JEB associated with pyloric atresia (PA) results from mutations in the alpha6 and beta4 integrin genes. In this study, we examined three EB patients associated with PA from two distinct families. Electron microscopy detected blister formation within the basal keratinocytes leading to the diagnosis of EBS. Surprisingly, immunohistochemical studies using monoclonal antibodies to a range of basement membrane proteins showed that the expression of plectin was absent or markedly attenuated. Sequence analysis demonstrated four novel PLEC1 mutations. One proband was a compound heterozygote for a nonsense mutation of Q305X and a splice-site mutation of 1344G-->A. An exon-trapping experiment suggested that the splice-site mutation induced aberrant splicing of the gene. The second proband harbored a heterozygous maternal nonsense mutation, Q2538X and homozygous nonsense mutations R1189X. Analysis of the intragenic polymorphisms of PLEC1 suggested that R1189X mutations were due to paternal segmental uniparental isodisomy. These results indicate that PLEC1 is a possible causative gene in this clinical subtype, EBS associated with PA. Furthermore, two patients out of our three cases died in infancy. In terms of clinical prognosis, this novel subtype is the lethal variant in the EBS category.

Epidermolysis Bullosa Simplex↗
PubMed2005

Relationships between echocardiographic findings, pulse wave velocity, and carotid atherosclerosis in type 2 diabetic patients.

The purpose of the present study was to analyze the relationships between echocardiographic findings, brachial-ankle pulse wave velocity, and carotid atherosclerosis in type 2 diabetic patients. In 70 type 2 diabetic patients without cardiovascular disease, pulse wave velocity was measured using an automatic waveform analyzer, and the carotid plaque score was obtained by carotid ultrasonography. The left ventricular wall thickness and the indexes of left ventricular diastolic function (the peak velocity of early rapid filling [E velocity], the peak velocity of atrial filling [A velocity], and the E/A ratio) were obtained by echocardiography. Brachial-ankle pulse wave velocity correlated significantly with the carotid plaque score, but the correlation was weak (r=0.37, p=0.001). The brachial-ankle pulse wave velocity demonstrated a strong correlation with the A velocity (r=0.73, p<0.001), the ratio of E to A (E/A) (r=-0.63, p<0.001), and the deceleration time of the E velocity (r=0.48, p<0.001). Stepwise regression analysis showed that the A velocity (beta coefficient=0.42, p<0.001) and ventricular septal thickness at the left ventricular outflow tract (beta coefficient=0.27, p=0.001) were independently associated with brachial-ankle pulse wave velocity. Stepwise regression analysis indicated that ventricular septal thickness at the left ventricular outflow tract (beta coefficient=0.38, p=0.001) was independently associated with the plaque score. These results indicate that left ventricular diastolic dysfunction as revealed by increased peak velocity of atrial filling reflects arterial stiffening in type 2 diabetic patients. In addition, myocardial wall thickening at the left ventricular outflow tract reflects not only arterial stiffening but also carotid atherosclerosis. Therefore, these abnormal echocardiographic findings of left ventricular diastolic dysfunction and myocardial wall thickening may be useful markers of the presence of progressive arteriosclerosis in type 2 diabetic patients.

Aged↗
PubMed2005

Severe community-acquired pneumonia in an intensive care unit: risk factors for mortality.

OBJECTIVE: To evaluate severe community-acquired pneumonia (SCAP) patients in an intensive care unit (ICU) with regard to risk factors for mortality and to compare ICU patients with matched non-ICU patients to evaluate whether our judgement for ICU admission was appropriate or not. MATERIALS AND METHODS: During a 7-year period, all patients with CAP who were admitted to the ICU were examined. They underwent clinical and radiographic evaluations, and two commonly used severity of illness scores were also calculated using the Simplified Acute Physiological Score (SAPS) and the Acute Physiology and Chronic Health Evaluation (APACHE) II methods. To detect risk factors for ICU admission using existing guidelines, each study patient was matched with two patients hospitalized in a general medical ward. RESULTS: Seventy-two patients were identified during the study period. Their mean age was 72.9 years, and 35 patients (48.6%) subsequently died. For the univariate analysis, there were significant differences with the pulse rate > or = 130/min, blood urea nitrogen > or = 30 mg/dl, multilobar shadow, SAPS > or = 13, APACHE II > or = 23, and the occurrence of septic shock between the survivors and those who died. For the multivariate analysis, septic shock (p = 0.0005, odds ratio of 26.6) and blood urea nitrogen > or = 30 mg/dl (p = 0.037, odds ratio of 5.38) were associated with mortality. Regarding the characteristics of different clinical predictions for ICU admission, the revised American Thoracic Society criteria might have been the most accurate. CONCLUSION: Septic shock was associated with high mortality, which is a more accurate and higher predictor of mortality than was physical examination, laboratory or radiographic findings.

Aged↗
PubMed2005

Efficient immobilization of enzymes on microchannel surface through His-tag and application for microreactor.

We developed a simple immobilisation method for His-tagged enzymes on a microchannel surface. It facilitates immobilisation of protein molecule on microchannel surface through Ni-complex, using crude or purified protein solutions. By this method, we could immobilize proteins on microcapillary constantly. This method might be useful for further development of microreactor with reversibly immobilized enzymes.

Animals↗
PubMed2005

[Effect of oral beta2-stimulant on pulmonary function in asthma patients treated with multiple medications].

This study was designed to evaluate the effect of discontinuing oral beta2-stimulant in patients with asthma who were being treated with multiple medications. Thirty-two asthmatics controlled under multiple medications who had a stable PEF were entered. Patient symptoms, PEF, FEV10, V75,V50, and V25 were evaluated before and after discontinuing beta2-stimulant. Results showed that after discontinuing beta2-stimulant, there was little change in symptoms, PEF, or FEV10, and only two patients had to be re-medicated with oral beta2-stimulant. However, deterioration of V50 and V25 were clearly observed, suggesting that oral beta2-stimulant had an affect on dilatation of the small airway. Based on our data, we should regard that when discontinuing oral beta2-stimulant from combined use, the lung function reflecting the small airway decreases even if no change of symptoms is observed.

Administration, Inhalation↗
PubMed2005

[Measurement of peak inspiratory flow with asthma: effect of inhaled beta2-stimulant].

This study was designed to evaluate peak inspiratory flow (PIF) and peak expiratory flow (PEF) in 24 patients with mild asthma. After inhalation of a beta2-stimulant (beta2), PIF significantly increased from 173.0 +/- 67.0 (range 70-300 L/min) to 194.0 +/- 66.7 after 1 minute, and to 199.3 +/- 63.0 after 15 minutes (p < 0.0025, and p < 0.008, respectively). PEF also significantly increased. The previous inhalation of beta2 improved the efficacy of inhalation of dry powder. This evidence should be considered in performing patient education for effective methods of inhalation.

Administration, Inhalation↗
PubMed2005

[A case of pseudo-meigs syndrome due to ovarian clear cell adenocarcinoma].

A 59-year-old woman was admitted with dyspnea. A chest X-ray film revealed a large amount of pleural effusion at the both sides. No malignant cells were found in bilateral pleural effusions. Computed tomography (CT) of the abdomen showed a huge mass of the right ovary with a small amount of ascites, suggesting a diagnosis of Meigs syndrome. The ovarian mass and the neighboring organs, including the uterus and the greater omentum, were surgically removed, and then both the bilateral pleural effusion and ascites disappeared after the surgery. The histopathological examination revealed that the mass was clear cell adenocarcinoma of the ovary (stage IIc), indicating that the disease was pseudo-Meigs Syndrome. This is the second report of pseudo-Meigs Syndrome caused by clear cell adenocarcinoma of the ovary in Japan.

Adenocarcinoma, Clear Cell↗
PubMed2004

Functional analysis of the single nucleotide polymorphism (787T>C) in the tissue-nonspecific alkaline phosphatase gene associated with BMD.

UNLABELLED: Polymorphisms of the TNSALP gene have not previously been studied as a possible determinant for variations in BMD or as a predisposing genetic factor for osteoporosis. This study showed a significantly higher association between the 787T>C (Tyr246His) TNSALP gene and BMD among 501 postmenopausal women. Furthermore, the effects of amino acid substitution on the catalytic property of the protein translated from the 787T>C gene were examined. INTRODUCTION: Alkaline phosphatase (ALP) is present mainly on the cell membrane in various tissues and hydrolyzes a variety of monophosphate esters into inorganic phosphoric acid and alcohol. Human ALPs are classified into four types: tissue-nonspecific, intestinal, placental, and germ cell types. Based on studies of hypophosphatasia, which is a systemic skeletal disorder resulting from a tissue-nonspecific ALP (TNSALP) deficiency, TNSALP was suggested to be indispensable for bone mineralization. MATERIALS AND METHODS: We explored the possibility that the TNSALP gene may contribute to age-related bone loss in humans by examining the association between TNSALP gene polymorphisms and BMD in 501 Japanese postmenopausal women. To analyze the protein translated from the TNSALP gene associated with BMD, we constructed a TNSALP cDNA expression plasmid. RESULTS: We genotyped two single nucleotide polymorphisms (787T>C[Tyr246His] and 876A>G[Pro275Pro]), which proved to be in complete linkage disequilibrium. There was a significant difference in BMD and the BMD score adjusted for age and body weight (Z score) among haplotypes (p = 0.041), which was lowest among 787T/876A homozygotes, highest among 787T>C/876A>G homozygotes, and intermediate among heterozygotes. In subgroups divided by age, haplotypes were significantly associated with BMD in older postmenopausal women (>74 years; p = 0.001), but not in younger postmenopausal women (<74 years; p = 0.964). Expression of the 787T>C TNSALP gene using COS-1 cells showed that the protein translated from 787T>C had ALP-specific activity similar to that of 787T. Interestingly, the K(m) value for TNSALP in cells transfected with the 787T>C TNSALP gene was decreased significantly compared with that of cells bearing the 787T gene, reflecting the higher affinity. CONCLUSIONS: These results suggest that variation in TNSALP may be an important determinant of age-related bone loss in humans and that the phosphate metabolism pathway may provide a novel target for the prevention and treatment of osteoporosis.

Aged↗
PubMed2004

Effects of synthetic sphingosine-1-phosphate analogs on arachidonic acid metabolism and cell death.

Sphingolipid metabolites such as sphingosine regulate cell functions including cell death and arachidonic acid (AA) metabolism. D-erythro-C18-Sphingosine-1-phosphate (D-e-S1P), a sphingolipid metabolite, acts as an intracellular messenger in addition to being an endogenous ligand of some cell surface receptors. The development of S1P analogs may be useful for studying and/or regulating S1P-mediated cellular responses. In the present study, we found that several synthetic S1P analogs at pharmacological concentrations stimulated AA metabolism and cell death in PC12 cells. D-erythro-N,O,O-Trimethyl-C18-S1P (D-e-TM-S1P), L-threo-O,O-dimethyl-C18-S1P (L-t-DM-S1P) and L-threo-O,O-dimethyl-3O-benzyl-C18-S1P (L-t-DMBn-S1P) at 100 microM stimulated [(3)H]AA release from the prelabeled PC12 cells. L-t-DMBn-S1P at 20 microM increased prostanoid formation in PC12 cells. L-t-DMBn-S1P-induced AA release was inhibited by D-e-sphingosine, but not by the tested PLA(2) inhibitors. L-t-DMBn-S1P did not stimulate the activity of cytosolic phospholipase A(2alpha) (cPLA(2alpha)) in vitro and the translocation of cPLA(2alpha) in the cells, and caused AA release from the cells lacking cPLA(2alpha). These findings suggest that L-t-DMBn-S1P stimulated AA release in a cPLA(2alpha)-independent manner. In contrast, D-e-S1P and D-erythro-N-monomethyl-C18-S1P caused cell death without AA release in PC12 cells, and the effects of D-e-TM-S1P, L-t-DM-S1P and L-t-DMBn-S1P on cell death were limited. Synthetic S1P analogs may be useful tools for studying AA metabolism and cell death in cells.

Animals↗