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Biomedical subjects

K Inoue

Publications and source records attributed to K Inoue.

At least 631 records · Page 35Linked to original sources

Structural and functional analyses of photosynthetic regulatory genes regA and regB from Rhodovulum sulfidophilum, Roseobacter denitrificans, and Rhodobacter capsulatus.

Genes coding for putative RegA, RegB, and SenC homologues were identified and characterized in the purple nonsulfur photosynthetic bacteria Rhodovulum sulfidophilum and Roseobacter denitrificans, species that demonstrate weak or no oxygen repression of photosystem synthesis. This additional sequence information was then used to perform a comparative analysis with previously sequenced RegA, RegB, and SenC homologues obtained from Rhodobacter capsulatus and Rhodobacter sphaeroides. These are photosynthetic bacteria that exhibit a high level of oxygen repression of photosystem synthesis controlled by the RegA-RegB two-component regulatory system. The response regulator, RegA, exhibits a remarkable 78.7 to 84.2% overall sequence identity, with total conservation within a putative helix-turn-helix DNA-binding motif. The RegB sensor kinase homologues also exhibit a high level of sequence conservation (55.9 to 61.5%) although these additional species give significantly different responses to oxygen. A Rhodovulum sulfidophilum mutant lacking regA or regB was constructed. These mutants produced smaller amounts of photopigments under aerobic and anaerobic conditions, indicating that the RegA-RegB regulon controls photosynthetic gene expression in this bacterium as it does as in Rhodobacter species. Rhodobacter capsulatus regA- or regB-deficient mutants recovered the synthesis of a photosynthetic apparatus that still retained regulation by oxygen tension when complemented with reg genes from Rhodovulum sulfidophilum and Roseobacter denitrificans. These results suggest that differential expression of photosynthetic genes in response to aerobic and anaerobic growth conditions is not the result of altered redox sensing by the sensor kinase protein, RegB.

Aerobiosis↗

Quantitation of hepatitis B virus genomic DNA by real-time detection PCR.

Quantitation of hepatitis B virus (HBV) DNA in serum is a useful method for the monitoring of HBV replication. We attempted to develop a quantitative assay system for HBV DNA that is more sensitive, accurate, and reproducible than existing systems. We detected HBV DNA by real-time detection PCR (RTD-PCR) based on Taq Man chemistry. The efficacy of this assay was evaluated by quantitatively measuring sequential levels of synthetic DNA and DNA in clinical serum samples. The detection limit of this system was as few as 10 DNA copies/reaction. A linear standard curve was obtained between 10(1) and 10(8) DNA copies/reaction. The coefficient of variation for both intra- and interexperimental variability indicated remarkable reproducibility. This system detected HBV DNA in 100% of chronic hepatitis B patients tested and never detected HBV DNA in healthy volunteers who were negative for HBV markers. These observations suggest that RTD-PCR is an excellent candidate for a standard HBV quantification method.

Adult↗

Association of oestrogen receptor gene polymorphisms with age at onset of rheumatoid arthritis.

OBJECTIVE: In view of the possible role of oestrogens in the pathogenesis of rheumatoid arthritis (RA), this study investigated the association between oestrogen receptor (OR) gene polymorphisms and RA. METHODS: Pvu II and Xba I restriction fragment length polymorphisms of the OR gene were analysed in 70 male and 240 female patients with RA, and in 300 male and 350 female controls. The absence or presence of restriction sites were represented as P, p (Pvu II) or X, x (Xba I). The distribution of OR genotypes was compared between the RA and control subjects by sex. RA patients were divided into subgroups according to their OR genotypes, then the age at onset, seropositivity, and rheumatoid nodule positivity were compared between the subgroups. RESULTS: The OR genotype frequency of distribution did not have significant differences between the male RA and male controls nor between the female RA and female controls. In women with RA, there was a significant difference of age at onset between the subgroups (uncorrected p = 0.047, corrected p = 0.94). Female patients with the OR genotype PPxx (homozygote of Px) tended to have developed RA at a younger age, whereas those with PPXX and ppxx (lack of Px haplotype) developed RA at an older age. In men with RA, there was no association between the OR genotype and age at onset. In seropositivity and rheumatoid nodule positivity, there was no significant difference between subgroups for either sex. CONCLUSIONS: Some variants of the OR gene are related to the onset of RA in women in certain age periods, suggesting the role of the interaction between the OR gene and serum concentrations of oestrogen at the onset of the disease.

Adult↗

Changes in the incidence and prevalence of rheumatoid arthritis in Kamitonda, Wakayama, Japan, 1965-1996.

OBJECTIVE: To evaluate secular trends in the incidence and prevalence of rheumatoid arthritis (RA) in Japan. METHODS: The incidence and prevalence of RA were determined in a longitudinal population based study in the Kamitonda district, Wakayama, Japan, from 1965 to 1996. RESULTS: In the study area consisting of about 3000 inhabitants, 16 incident cases, satisfying definite RA by the Rome criteria were detected during the study period. The age and sex adjusted incidence in both men and women combined and the age adjusted incidence in women significantly decreased (p<0.025 and p<0. 01, respectively). The age and sex adjusted prevalence in all inhabitants tended to decrease (p<0.1), and the age adjusted prevalence in women significantly declined (p<0.025). In men, however, neither incidence nor prevalence showed significant change. CONCLUSIONS: The decline of incidence and prevalence of female RA may be reducible to some environmental changes preferentially occurring more obviously in Japanese women than in men. Because the use of oral contraceptives has been extremely low in Japan, the decline should be explained by other factors.

Adolescent↗

Polymorphic CAG repeats of the androgen receptor gene and rheumatoid arthritis.

OBJECTIVE: In view of the possible role of androgens in the pathogenesis of rheumatoid arthritis (RA), this study investigated the association between repeat lengths of CAG microsatellites of the androgen receptor (AR) gene and RA. METHODS: The number of CAG repeats in exon 1 of the AR gene was determined in 90 men and 276 women with RA, as well as in 305 male and 332 female controls. RESULTS: The male RA patients tended to have shorter repeats than the male controls (22.5 versus 23.1, p=0.07), whereas the female RA patients had similar repeats to the female controls (22.7 versus 22.9, p=0.17). Patients of both sexes were divided into younger and older age at onset groups, and compared with younger and older controls. Younger onset male RA patients had significantly shorter CAG repeat lengths than the younger male controls (21.8 versus 23.2, p=0.007) or the older onset male RA patients (21.8 versus 23.2, p=0.04). Older onset male RA and both younger and older onset female RA patients had similar CAG repeat lengths when compared with their controls. Neither seropositivity nor rheumatoid nodule positivity had a significant relation with CAG repeat lengths. CONCLUSION: Shorter CAG repeats of the AR gene, presenting high levels of transactivation activity, are related to younger age onset male RA, suggesting the possible role of androgens as a modulating factor.

Adult↗

Expression of p53 and glutathione S-transferase-pi relates to clinical drug resistance in non-small cell lung cancer.

To determine the predictive value of the expression of p53 and glutathione S-transferase-pi (GST-pi) with respect to chemotherapy response, immunostaining was performed on transbronchial biopsy specimens from previously untreated patients with non-small cell lung cancer. Of the 54 patients, 34 patients (63%) and 37 patients (69%) were positive for p53 and GST-pi, respectively. The response rates in the p53-positive and p53-negative group were 15 and 45%, and those in GST-pi-positive and GST-pi-negative groups were 16 and 47%, respectively. A multiple logistic regression analysis revealed that positive immunostaining for GST-pi was a significant risk factor for clinical chemotherapy resistance. The combination of these two markers was the most important independent factor in predicting a response to chemotherapy in multiple logistic regression analysis. Immunohistochemical expression of p53 and GST-pi was independently related to clinical chemoresistance in patients with non-small cell lung cancer. Combined use of these two biomarkers may be a useful predictor of clinical chemoresistance.

Adult↗

Alternative angiotensin II formation in rat arteries occurs only at very high concentrations of angiotensin I.

Contrary to previous reports, recent enzymatic assays showed the predominance of chymase-like activity in rat arteries. We determined the existence and significance of such alternative pathways in rat carotid arteries by measuring contraction of arterial rings in organ baths and blood pressure in conscious rats. Hamster aorta served as a positive control for chymase. Temocapril (30 micromol/L) inhibited the contractions to angiotensin (Ang) I (10(-9) to 10(-5) mol/L) except at high concentrations of Ang I (>10(-7) mol/L). Addition of chymostatin (100 micromol/L) to temocapril exerted a synergistic inhibitory effect. Hamster aorta gave similar results, except that temocapril was 30-fold less effective than in rat arteries. [Pro(11), D-Ala(12)]Ang I (10(-8) to 10(-5) mol/L), a chymase-specific substrate, provoked similar responses in rat and hamster arteries; chymostatin, but not temocapril, attenuated the responses. CV 11974 (30 micromol/L), an Ang II type 1 receptor antagonist, abolished the responses to both peptides. In conscious rats, Ang I (0.03 to 30 microg/kg) and [Pro(11),D-Ala(12)]Ang I (7 to 700 microg/kg) produced similar pressor responses. Not only CV 11974 (1 mg/kg) but also temocapril (2 mg/kg) abolished Ang I-induced responses in vivo. CV 11974, but not temocapril, inhibited responses to [Pro(11), D-Ala(12)]Ang I. Our results showed the presence of the alternative pathway in rat arteries, but it did not play a major role. Arteries with the opposing characteristics of chymase responded equally to [Pro(11),D-Ala(12)]Ang I. These findings suggest that biochemical and [Pro(11),D-Ala(12)]Ang I-derived results may not reflect the functional significance of chymase.

Angiotensin I↗

IL-17 in synovial fluids from patients with rheumatoid arthritis is a potent stimulator of osteoclastogenesis.

IL-17 is a newly discovered T cell-derived cytokine whose role in osteoclast development has not been fully elucidated. Treatment of cocultures of mouse hemopoietic cells and primary osteoblasts with recombinant human IL-17 induced the formation of multinucleated cells, which satisfied major criteria of osteoclasts, including tartrate-resistant acid phosphatase activity, calcitonin receptors, and pit formation on dentine slices. Direct interaction between osteoclast progenitors and osteoblasts was required for IL-17-induced osteoclastogenesis, which was completely inhibited by adding indomethacin or NS398, a selective inhibitor of cyclooxgenase-2 (COX-2). Adding IL-17 increased prostaglandin E2 (PGE2) synthesis in cocultures of bone marrow cells and osteoblasts and in single cultures of osteoblasts, but not in single cultures of bone marrow cells. In addition, IL-17 dose-dependently induced expression of osteoclast differentiation factor (ODF) mRNA in osteoblasts. ODF is a membrane-associated protein that transduces an essential signal(s) to osteoclast progenitors for differentiation into osteoclasts. Osteoclastogenesis inhibitory factor (OCIF), a decoy receptor of ODF, completely inhibited IL-17-induced osteoclast differentiation in the cocultures. Levels of IL-17 in synovial fluids were significantly higher in rheumatoid arthritis (RA) patients than osteoarthritis (OA) patients. Anti-IL-17 antibody significantly inhibited osteoclast formation induced by culture media of RA synovial tissues. These findings suggest that IL-17 first acts on osteoblasts, which stimulates both COX-2-dependent PGE2 synthesis and ODF gene expression, which in turn induce differentiation of osteoclast progenitors into mature osteoclasts, and that IL-17 is a crucial cytokine for osteoclastic bone resorption in RA patients.

Animals↗

An imbalance in plasma prostanoids in patients with Raynaud's phenomenon and pulmonary vasospasm.

Raynaud's phenomenon has been suggested as a predisposing factor for pulmonary vasospasm which may lead to pulmonary hypertension, but the occurrence of cold stimulus-induced pulmonary vasospasm has been inconsistent. Such inconsistent pulmonary vascular responses may be caused by differences in the production of endogenous vasodilators and vasoconstrictors among patients. Fourteen patients with Raynaud's phenomenon associated with mixed connective tissue disease (n=10) or systemic sclerosis (n=4) participated in the study. Right heart catheterization was performed before and after a cold pressor test, immersing a hand in cold water (15 degrees C) for 5 min. Plasma levels of 6-keto prostaglandin (PG)F1alpha, thromboxane (TX)B2 and endothelin (ET)-1 in the mixed venous blood were measured. Mean pulmonary artery pressure increased after the cold pressor test in five of 14 patients, and the patients were divided into those with pulmonary vasospasm (responders) and those without vasospasm (nonresponders). After the cold pressor test, levels of 6-keto PGF1alpha increased significantly in nonresponders (p<0.01) and decreased significantly in responders (p<0.05). The ratios of 6-keto PGF1alpha to TXB2 significantly increased in nonresponders (p<0.01) but not in responders and the difference between responders and nonresponders after the cold pressor test was also statistically significant (p<0.05). No significant change in plasma ET-1 levels occurred in either responders or nonresponders. The results suggest that an impaired production of prostaglandin I2 and an imbalance between prostaglandin I2 and thromboxane A2 are associated with the occurrence of pulmonary vasospasm induced by Raynaud's phenomenon.

6-Ketoprostaglandin F1 alpha↗

Molecular mechanisms of the negative effect of insulin-like growth factor-I on growth hormone gene expression in MtT/S somatotroph cells.

Although insulin-like growth factor-I (IGF-I) is shown to have a suppressive effect on GH gene expression at the pituitary level, its molecular mechanism has not yet been clarified. To study the issue, we established a new in vitro system using MtT/S, a recently established rat somatotroph tumor cell line that retains the basic characteristics of somatotroph function. Plasmids containing the GH 5' promoter (approximately 1.75 kb or shorter)-luciferase fusion gene were transfected stably or transiently into the cells, and the effect of IGF-I on the GH promoter activity was estimated by a luciferase assay. The results showed that IGF-I inhibited GH promotor activity (more than 50% suppression) in a time- and dose-related manner. IGF-I also inhibited GH secretion. A study using deletion mutants of the GH promoter revealed that the negative effect was maintained in the shortest construct (-80 to +6), suggesting that IGF-I-related factor is acting at the region very close to the minimal promoter. Interestingly, the negative effect was completely eliminated by a PI3 kinase inhibitor wortmannin (1 microM), whereas a MAP kinase inhibitor PD98059 (20 microM) or S6 kinase inhibitor rapamycin (10 nM) did not influence the effect. Our results suggest that IGF-I suppresses GH gene expression at the transcriptional level and that the PI3 kinase-mediated signaling pathway plays a major role in the negative effect of IGF-I. We believe that our system using MtT/S cells is an excellent experimental model system for studying the cellular and molecular mechanisms of the transcriptional regulation of GH in vitro.

Androstadienes↗

Immunocytochemical localization of prolactin-releasing peptide in the rat brain.

A hypothalamic peptide that stimulates PRL release has recently been found as a ligand of an orphan receptor and named PRL-releasing peptide (PrRP). PrRP and its receptor were mainly detected in the hypothalamus and pituitary gland, respectively. Its characteristics suggested PrRP to be a novel hypophysiotropic peptide that stimulates the anterior pituitary PRL cell; however, this remained to be confirmed morphologically. We therefore performed an immunocytochemical study to locate PrRP in the rat brain using the region-specific monoclonal antibodies, P2L-1C and P2L-1T, which recognize the C-terminal and the internal sequence of PrRP, respectively. Our results clearly show that dense immunoreactive nerve fiber networks are present in the paraventricular hypothalamic nucleus, supraoptic nucleus, paratenial thalamic nucleus, basolateral amygdaloid nucleus, and bed nucleus of the stria terminalis. A small number of PrRP nerve fibers was also observed in the neural lobe of the hypophysis. However, no immunopositive fiber was observed in the external region of the median eminence, which is known to be the release site of the classical hypophysiotropic hormones. Also, the distribution of PrRP was not changed during the estrous cycle. We therefore concluded that PrRP probably differs from classical hypothalamic releasing hormones. We found the immunoreactive cell bodies to be mainly in the caudal portion of the dorsomedial hypothalamic nucleus and solitary nucleus. A double immunocytochemical procedure revealed that some PrRP-positive neurons showed synaptic contact with oxytocin-positive cell bodies in the paraventricular hypothalamic nucleus, which suggests that PrRP regulates the function of oxytocin neurons. This is the first report to demonstrate the localization of the novel hypothalamic peptide, PrRP, and we therefore suggest that it takes part in a variety of brain functions. However, it is not yet known how PrRP is transported to the pituitary gland, which is the site that contains the greatest concentration of receptors to this new peptide. Therefore, additional work will be required to resolve this discrepancy between ligand and receptor site location.

Animals↗

Regulation of growth hormone-releasing hormone receptor messenger ribonucleic acid expression by glucocorticoids in MtT-S cells and in the pituitary gland of fetal rats.

Regulation of GH-releasing hormone receptor (GHRH-R) messenger RNA (mRNA) expression was studied, with the ribonuclease protection assay, in the fetal rat pituitary gland and in MtT-S clonal cells. GHRH-R mRNA was first detected on embryonic day (E)19 and increased rapidly thereafter, to reach a maximum at E21. Incubation of E17 or E18 pituitaries with 50 nM dexamethasone (DEX), a synthetic glucocorticoid, induced GHRH-R mRNA expression, suggesting that glucocorticoids play a pivotal role in the developmental expression of this mRNA. In E19 pituitaries, 24 h treatment with DEX increased GHRH-R mRNA by 60%, and GH mRNA by 76%, but did not affect pit-1 mRNA level, suggesting that the effect of DEX is specific for expressions of GH mRNA and GHRH-R mRNA. The accumulation of GHRH-R mRNA by DEX was time dependent, and it was slightly enhanced by the protein synthesis inhibitor, puromycin (100 microM). In MtT-S cells (a pituitary cell line established from an estrogen-induced tumor), DEX induced GHRH-R mRNA expression within 2 h in a dose-dependent manner. This induction was augmented by puromycin (100 microM) or cycloheximide (3.5 microM). However, the RNA synthesis inhibitor Actinomycin D (1 microM) completely inhibited GHRH-R mRNA accumulation in response to either DEX or DEX plus puromycin, suggesting that glucocorticoids induce GHRH-R mRNA mainly through stimulation of mRNA transcription. These results suggest: that GHRH-R mRNA accumulation in the fetal pituitary gland of rats normally occurs at E19, probably because of the direct action of glucocorticoids on the pituitary gland, to stimulate GHRH-R mRNA transcription; and that the expression of glucocorticoid receptors is an important event in GH cell development in rats. Accordingly, immunocytochemical results suggest an increase in glucocorticoid receptors in immature GH cells between E17 and E18. The present results also imply that MtT-S cells may be a good model in which to further study the molecular mechanisms of the regulation of GHRH-R gene expression.

Animals↗

A 60 kDa plasma membrane protein changes its localization to autophagosome and autolysosome membranes during induction of autophagy in rat hepatoma cell line, H-4-II-E cells.

We previously reported the preparation and characterization of an antibody against membrane fraction of autolysosomes from rat liver (J. Histochem. Cytochem. 38, 1571-1581, 1990). Immunoblot analyses of total membrane fraction of a rat hepatoma cell line, H-4-II-E cells by this antibody suggested that H-4-II-E cells expressed several autolysosomal proteins, including a protein with apparent molecular weight of 60 kDa. It was suggested that this 60 kDa protein was a peripheral membrane protein, because it was eluted from the membrane by sodium carbonate treatment. We prepared an antibody against this 60 kDa protein by affinity purification method, and examined its behavior during induction of autophagy. Autophagy was induced by transferring the cells from Dulbecco's modified Eagle medium (DMEM) containing 12% fetal calf serum into Hanks' balance salt solution. In DMEM, the 60 kDa protein showed diffused immunofluorescence pattern, and immunoelectron microscopy suggested that this protein was located on the extracellular side of the plasma membrane. After inducing autophagy, the immunofluorescence configuration of the 60 kDa protein changed from the diffused pattern to a granulous one. Immunoelectron microscopy showed that the 60 kDa protein was localized on the luminal side of the limiting membrane of autolysosomes and endosomes. In the presence of bafilomycin A1 which prevents fusion between autophagosomes and lysosomes, the 60 kDa protein was localized on the limiting membrane of the autophagosomes and endosomes. These results suggest that the 60 kDa protein is transported from the plasma membrane to the autophagosome membrane through the endosomes.

Animals↗

Involvement of serotonin in zimelidine-induced hyperglycemia in mice.

Effects of a selective serotonin reuptake inhibitor, zimelidine, on plasma glucose was studied in mice. Zimelidine dose-dependently induced hyperglycemia, although it did not change insulin levels. To determine the involvement of the serotonergic system in zimelidine-induced hyperglycemia, effects of the 5-HT depleter p-chlorophenylalanine(pCPA) were examined. pCPA significantly reduced zimelidine-induced hyperglycemia. This suggests that zimelidine-induced hyperglycemia is mediated by the serotonergic system through its 5-HT reuptake inhibition.

Animals↗

Sensitivity of real time viral detection by an optical biosensor system using a crude home-made antiserum against measles virus as a ligand.

Virus identification in clinical materials during acute phase infections could give necessary information for the treatment of infections by human immunoglobulin (hIg) or interferon (IF). But because of a lack of information, most virus infections have not been treated. We have tried to develop a real time detection system for viruses in general using an optical biosensor and a model virus, Herpes simplex virus Type 1 (HSV-1), and have proved that the HSV-1 virus propagated in Vero cells and diluted in minimum essential medium (MEM) with 10% fetal bovine serum (FBS) could be detected in high sensitivity close to 10 infectious units (50% tissue culture infective dose [TCID50] units) using purified cellular receptor molecules as the ligand because the receptor could be the most specific ligand. However, because ligands available for this system to identify various viral infections in general are limited, we also tested this system using a purified polyclonal antibody which contained many other antigens as the ligand, and produced sensitivity comparable to that using the receptor as a ligand. In this paper, we tested the sensitivity by this system under the worst condition. That is, we used a crude home-made rabbit antiserum against measles virus with host cell debris as a ligand. It was found that less than 500 infectious (TCID50) units of virus were required for detection in a 100 microl solution, and that the efficacy of the commercially available hIg was also estimated by this system. This result suggested that this real time viral detection and titration system was applicable for the diagnosis of all viral infections even under difficult conditions without requiring any complex skills, with high enough sensitivity for clinical purposes. The efficacy of hIg preparations could also be evaluated by this system at the same time of the clinical material sampling.

Animals↗

A rapid and simple detection of genetic defects responsible for the phenotypic polymorphism of cytochrome P450 2C19.

A rapid and simple cytochrome P450 (CYP) 2C19 genotyping system was established by making several modifications in previously reported procedures. PCR conditions were modified to be capable of simultaneous amplification of CYP2C19m1 and CYP2C19m2 regions. Intensive bands of 169 bp for the CYP2C19m1 region and 329 bp for the CYP2C19m2 region with low background were obtained by using PCR condition involving an initial denaturation of 5 min at 94 degrees C, 35 cycles of 1 min at 94 degrees C; 1 min at 53 degrees C; 1 min at 72 degrees C, and final extension of 5 min at 72 degrees C. Next, the optimal restriction enzyme digestion conditions were determined by using PCR products from a subject of wt/wt genotype. Both products were completely digested with 5 U of the corresponding enzyme (Sma I for CYP2C19m1 and Bam HI for CYP2C19m2) for 1 h incubation at an optimal temperature. The incidence (16%; 5/32) of subjects homozygous for mutant alleles determined by an established assay system agreed well with the incidence of the poor metabolizer (PM) phenotype in the Japanese population. The established genotyping system would, therefore, be applicable to the clinical laboratory testing of patients with a PM phenotype of CYP2C19 to select appropriate and effective medication.

Aryl Hydrocarbon Hydroxylases↗

Determination of valproic acid in human serum by high-performance liquid chromatography with fluorescence detection.

A simple and highly sensitive high-performance liquid chromatographic method is described for the determination of valproic acid in human serum. The method is based on the direct derivatization of serum sample with 6,7-methylenedioxy-1-methyl-2-oxo-1,2-dihydroquinoxaline-3-ylpr opionohydrazide. The derivatization reaction proceeds in aqueous solution in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at 37 degrees C. The resulting derivatives were separated on a reversed-phase column (YMC Pack ODS-A) with isocratic elution and were fluorimetrically detected at 440 nm with excitation at 365 nm. The detection limit (signal-to-noise ratio=3) for valproic acid added to serum sample was 0.1 microg (700 fmol)/ml serum sample (2.3 fmol on column). The method was applied to determine the unbound- and total-valproic acid levels in the serum obtained from three healthy volunteers after oral administration of the drug (600 mg).

Adult↗