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Biomedical subjects

Y Ouchi

Publications and source records attributed to Y Ouchi.

At least 145 records · Page 8Linked to original sources
PubMed1999

Alterations in binding site density of dopamine transporter in the striatum, orbitofrontal cortex, and amygdala in early Parkinson's disease: compartment analysis for beta-CFT binding with positron emission tomography.

We investigated changes in the kinetics in the binding of the dopamine transporter probe 2-beta-carbomethoxy-3beta-(4-[11C]fluorophenyl)tropane (beta-CFT) in living brain by compartmental analysis, using positron emission tomography in unmedicated patients with Parkinson's disease (PD) (Hoehn and Yahr stages I-II). With dynamic positron emission tomographic data from 90-minute acquisitions and metabolite-corrected arterial input functions, binding potentials (k3/k4) were calculated by using estimated rate constants (K1 - k4). In this analysis, the magnitude of the distribution volume (K1/k2) measured in the cerebellum, in which specific binding is negligible, was used as a constrained value for fitting in binding regions. Statistics showed that k3/k4 values in the striatum, the orbitofrontal cortex, and the amygdala were significantly lower in PD patients than in normal controls, whereas there were no differences in K1/k2 ratios and structural volumes between the groups. Correlation analysis showed that the putaminal and orbitofrontal binding levels were correlated positively with motor and mentation scores, respectively, of the Unified Parkinson's Disease Rating Scale. These results indicated that not only the striatal but also the orbitofrontal and amygdalar presynaptic dopaminergic functions were altered in early PD. The reductions in these mesocortical/mesolimbic functions might contribute to the mental and behavioral impairment observed in PD.

Aged↗
PubMed1999

[Effect of mechanical damage on ex vivo DNA virus vector-mediated gene transduction in epithelial cells of murine trachea].

The mechanism of Adenovirus (Ad) and Adeno-associated virus (AAV) vector-mediated gene transduction in murine tracheae has not been fully understood. Excised tracheae from mice were exposed to either Ad vector (Ad-CMV-LacZ) or AAV vector (AAV-CMV-LacZ) for 1 hour. LacZ gene expression in tracheal epithelial cells was detected by X-gal staining. Only patch distributions of LacZ expressing cells were observed. The percentage of LacZ expressing cells to total cells was less than 1% with either vector. Ad-mediated LacZ transduction was increased by mechanical damage using forceps. AAV-mediated gene transduction in tracheal epithelial cells was also increased by mechanical damage. Furthermore, this increased expression of vector LacZ by damaged epithelial cells was not affected by pretreatment with anti-ICAM-1 mAb or platelet-activating factor receptor antagonist. Although the Ad and AAV vectors were inefficient in transferring genetic material to murine trachea ex vivo, our results suggest that mechanical damage can enhance their transduction efficiency.

Adenoviruses, Human↗
PubMed1999

[The simple swallowing provocation test as a means of screening for swallowing disorders: a comparison with the water swallowing test].

The sensitivity and specificity of the simple swallowing provocation test (S-SPT) were evaluated in a group of patients who were being examined for aspiration pneumonia (ASP) (ASP group: 72.5 +/- 3.9 years old) and in a group of age-matched control subjects (CTRL group: 69.5 +/- 2.9 years old). The S-SPT was evaluated in terms of the swallowing response and latent time (LT) for swallowing after a bolus injection of 0.4 ml of distilled water at the suprapharynx. Responses to the S-SPT were classified as normal or abnormal, dependent on induction of the swallowing reflex within 3 seconds after bolus injection. The sensitivity and specificity of the S-SPT in detecting ASP were calculated. Of the 40 patients in the ASP group, 18 were given a diagnosis of ASP on the basis of clinical findings and laboratory examinations. The sensitivity and specificity of the S-SPT were 94.4% and 86.4%, respectively, compared to 77.8% and 68.1%, respectively, for the water swallowing test. Because the S-SPT can be performed without any need for special patient effort or cooperation, it should be effective in diagnosing ASP in a wide variety of patients, including those who are bedridden.

Aged↗
PubMed1998

Molecular cloning of a novel RING finger-B box-coiled coil (RBCC) protein, terf, expressed in the testis.

RING finger is a variant zinc finger motif present in a new family of proteins including transcription regulators. Here, utilizing the polymerase chain reaction with degenerate primers, we isolated a genomic DNA fragment containing the RING finger motif. Using this fragment as a probe, we have identified a novel cDNA from rat testis library. Then, the human homologue of the terf cDNA was also isolated from a testis library. This gene was designated testis RING finger protein (terf) because the corresponding transcripts were detected almost exclusively in the testis by Northern blot analysis. Both cDNAs encode an open reading frame of 477 amino acids sharing high homology (74% identity at the protein level) between two species. The terf contains an N-terminal RING finger domain, one B-box domain, middle coiled-coil domain, and a C-terminal domain, belonging to the RING finger-B box-coiled coil (RBCC) family. Several RBCC proteins, such as PML, TIF1alpha and RFP, have transformation capabilities when found in chromosomal translocations. Among the members of the RBCC family, the terf shares highest homology (40% identity at the protein level) with RFP that is expressed only in the testis in normal tissues. Structural similarity raises the possibilities that the terf gene might be also involved in carcinogenesis or cell transformation.

Amino Acid Sequence↗
PubMed1998

Estrogen attenuates endothelin-1 production by bovine endothelial cells via estrogen receptor.

To investigate the mechanism underlying the antiatherogenic effect of estrogen, we examined the role of estrogen in the regulation of endothelin-1 (ET-1) production by cultured bovine carotid arterial endothelial cells. Treatment of the cells with 17beta-estradiol dose dependently inhibited gene expression and peptide secretion of ET-1. This inhibitory effect of 17beta-estradiol was more marked when ET-1 production was stimulated by transforming growth factor-beta1. Simultaneous addition of ICI 182,780, a pure estrogen receptor antagonist, completely blocked the effect of 17beta-estradiol, indicating that 17beta-estradiol acted via estrogen receptor. These results suggest that reduced ET-1 production by endothelial cells may be involved in the vasoprotective effect of estrogen.

Animals↗
PubMed1998

Cytokine-induced expression of parathyroid hormone-related peptide in cultured human vascular endothelial cells.

Parathyroid hormone-related peptide (PTHrP) is a potent vasodilatory peptide whose expression has been demonstrated in various tissues. The present study was undertaken to examine the regulation of PTHrP expression in cultured endothelial cells derived from human umbilical vein. Immunoradiometric assay revealed that the amount of PTHrP in the conditioned medium was increased by both tumor necrosis factor alpha (TNF-alpha) and interleukin 1beta (IL-1beta) in both a time- and a dose-dependent manner. The induction of PTHrP mRNA was also observed, with a peak after 2 hours of incubation with both TNF-alpha and IL-1beta. Angiotensin II, endothelin-1, and arginine vasopressin had no affect on PTHrP production. Our results suggest that PTHrP produced in vascular endothelial cells in response to cytokines may modulate vascular function as a local factor.

Cells, Cultured↗
PubMed1998

Molecular cloning and characterization of human estrogen receptor betacx: a potential inhibitor ofestrogen action in human.

We have identified and characterized a novel human estrogen receptor (ER) beta isoform, ERbetacx, which is truncated at the C-terminal region but has an extra 26 amino acids due to alternative splicing. The ERbetacx transcript is expressed in testis, ovary, thymus and prostate as well as in human cultured cell lines such as HEC-1, HOS-TE85 and Saos-2 cells. ERbetacx protein is also immunodetectable in these human cells. Biochemical analysis reveals that the average dissociation constants ( K d) of ERalpha and ERbeta for 17beta-estradiol (E2) are 0.2 and 0.6 nM respectively, but ERbetacx has no ligand binding ability. ERalpha and ERbeta proteins bind to the estrogen response element, whereas ERbetacx does not form any shifted complex in gel shift assays. In a transient expression assay, ERbetacx shows no ligand-dependent transactivation ability of a basal promoter and also cannot interact with a cofactor, TIF1alpha, in the presence or absence of E2. ERbetacx preferentially forms a heterodimer with ERalpha rather than that with ERbeta, inhibiting DNA binding by ERalpha. Interestingly, however, it shows a significant dominant negative activity only against ERalpha transactivation. Thus, this study indicates that ERbetacx potentially inhibits ERalpha-mediated estrogen action and that alternative splicing of the C-terminal region and its inhibitory properties are characteristic of several members of nuclear receptor isoforms.

Amino Acid Sequence↗
PubMed1998

Expression of peroxisome proliferator-activated receptor gamma (PPARgamma) in rat aortic smooth muscle cells.

Peroxisome proliferator-activated receptor gamma (PPARgamma), a member of nuclear receptors, is expressed at a high level in adipose tissue and plays an important role in adipocyte differentiation. In the present study, we identified the expression of PPARgamma in rat aortic smooth muscle cells (RASMC) using reverse transcription-polymerase chain reaction and gel mobility shift assay. In addition, to investigate whether PPARgamma in RASMC is functional or not, we examined the effect of two specific ligands for PPARgamma, a thiazolidinedione anti-diabetic agent, troglitazone, and 15-deoxy-Delta12,14-prostaglandin J2, on the transcriptional activity of PPAR responsive element (PPRE). A significant increase in the activity of PPRE by addition of these ligands was found. These results suggest that in RASMC, target genes for PPARgamma may be activated by specific ligands for PPARgamma through PPRE in their promoters. In conclusion, PPARgamma is expressed and functional in vascular smooth muscle cells.

Animals↗
PubMed1998

Cross-inhibition of both estrogen receptor alpha and beta pathways by each dominant negative mutant.

Both estrogen receptor alpha (ERalpha) and the recently identified ERbeta are nuclear receptors that are activated by estrogen. It was reported that ERalpha and ERbeta form heterodimers. Here, we show that they activate transcription independently rather than synergistically via estrogen response elements (ERE). To show the cross-talk between ERalpha and ERbeta, we utilized dominant negative mutants of ERs constructed by C-terminal truncation. Interestingly, ERalpha1-530 inhibited transactivation not only by ERalpha but also by ERbeta, whereas ERbeta1-481 inhibited transactivation by ERalpha as well as by ERbeta. The GST pull-down assay also demonstrated the cross-interaction of these mutants with wild-type ERalpha and ERbeta. Thus, we found dominant negative mutants that block both ERalpha and ERbeta signaling pathways.

Amino Acid Sequence↗
PubMed1998

The complete primary structure of human estrogen receptor beta (hER beta) and its heterodimerization with ER alpha in vivo and in vitro.

Human estrogen receptor beta (hER beta) cDNA that encodes the full-length amino acid sequence has been isolated from testis poly(A)+ RNA with the combination of cDNA screening and reverse transcription-PCR. It is composed of a 1590-bp open reading frame and a segment of the 5'- and 3'-untranslated region (UTR) and encodes an additional 53 amino acids in the N-terminal region compared with the previously reported one. Protein interaction between ER alpha and ER beta was demonstrated in vitro by GST pull-down assay and in vivo by immunoprecipitation. Thus, this study indicates that ER alpha and ER beta can interact in vivo, cross-signaling each other.

Amino Acid Sequence↗
PubMed1998

Polymorphism of insulin-like growth factor I gene and bone mineral density.

The polymorphism of insulin-like growth factor-I (IGF-I) gene was examined in Japanese postmenopausal women to analyze the genetic background for osteoporosis. In this study, the dinucleotide (cytosine-adenine; CA) repeat sequence lying upstream of the transcription initiation site of this gene was examined. We named the most frequent allele including (CA) 19 as J allele. There were 6 alleles (J-4 containing 17 CA repeats: (CA)17, [J-2 (CA)18, J (CA)19, J + 2 (CA)20, J + 4 (CA)21, J + 6 (CA)22]) in the Japanese population. The genotype distribution was different from that of Caucasians. There was no different in bone mineral density (BMD) between the group with one or two alleles of each genotype and that without that genotype. When we separate the subjects into three groups having two alleles, one allele, and no alleles, the three subjects who possess the allele 'J-2' in both strands had low BMD (Z score of L2-4; -1.24 +/- 0.56, total body; -0.943 +/- 0.59, mean +/- SE). On the other hand, sequence of IGF-I gene in this study was different from reported sequence of IGF-I gene; that was 2 base pair (bp) deletion following 3'end of CArepeat (-645adenine/-646guanine). The present study showed that there was no association between the microsatellite polymorphism of IGF-I gene and BMD in Japanese postmenopausal women, but some possibility remains that the microsatellite polymorphism of IGF-I gene is useful to detect a kind of particular osteoporosis.

Absorptiometry, Photon↗
PubMed1998

Amino-terminal fragment (1-34) of parathyroid hormone-related protein inhibits migration and proliferation of cultured vascular smooth muscle cells.

We investigated the effects of amino-terminal fragment (1-34) of parathyroid hormone-related protein [PTHrP-(1-34)] on the migration and proliferation of vascular smooth muscle cells (VSMCs). Cultured VSMCs (5-9th passage) obtained from the aortas of male Wistar rats were used in this study. Migration of VSMCs was assessed using a modified Boyden's chamber. Proliferation of VSMCs was evaluated by measuring [3H]thymidine incorporation and counting cell numbers. PTHrP-(1-34) inhibited 10% fetal bovine serum (FBS)-induced increase in migration of VSMCs (61% of control at 1 micromol/l) in a concentration-dependent manner. PTHrP-(1-34) also inhibited 5% FBS-induced increase in [3H]thymidine incorporation (37% of control at 1 micromol/l) and cell number of VSMCs (33% of control at 1 micromol/l) in a concentration-dependent manner. Parathyroid hormone (PTH)-(1-34) inhibited the migration and DNA synthesis of VSMCs to a similar extent. PTHrP-(7-34), a PTH/PTHrP receptor antagonist, significantly inhibited these effects of PTHrP and PTH. PTHrP-(1-34) also inhibited platelet-derived growth factor-BB (5 ng/ml)-induced migration and DNA synthesis of VSMCs. These findings suggest that PTHrP-(1-34) inhibits the migration and proliferation of VSMCs through PTH/PTHrP receptors.

Animals↗
PubMed1998

Role of brain vasopressin in regulation of blood pressure.

Using recent advances in brain physiological, neurohistochemical, and molecular biological techniques, it could be demonstrated that the central action of vasopressin (VP) is important in cardiovascular regulation and in the pathogenesis of hypertension. VP is now known to be located in the area of the brain involved in cardiovascular regulation. Furthermore, in various pathophysiological states, brain VP secretion is regulated separately from the peripheral VP secretion system. The role of brain VP in the regulation of the circadian rhythm of blood pressure is becoming a topic of major interest.

Animals↗
PubMed1998

Effects of tibolone (Org OD14) treatment for 3 months on ovariectomy-induced osteopenia in 8-month-old rats on a low-calcium diet: preventive testing for 3 months.

Tibolone (Org OD14), (7alpha, 17alpha)-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn++ +-3-one, is a synthetic steroid with weak estrogenic, progestational, and androgenic properties. We investigated the prophylactic effects of tibolone on bone loss, bone strength, and plasma and urinary parameters in 8-month-old ovariectomized rats on a low-Ca diet. Oral administration of tibolone (0.03-3 mg/kg/day) was started immediately after ovariectomy (ovx) and continued for 3 months. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. Oral administration of tibolone (1 or 3 mg/kg/day) significantly prevented a decrease in BMD and bone ash density (bone ash weight/volume) of the global femur, and BMDs in the femoral distal and proximal regions. Also in the lumbar vertebrae, the ovx-induced reduction in BMD was prevented by tibolone (1 and 3 mg/kg/ day) treatment, resulting in a significantly higher lumbar vertebral (L-2) bone compression strength compared to the ovx control group. Neither ovx alone nor supplemented with tibolone affected the BMD or bending strength of the femoral mid-diaphysial region. Tibolone (0.03-3 mg/kg/day) significantly reduced the ovx-induced increases in serum osteocalcin level. Furthermore, tibolone inhibited an increase in the urinary hydroxyproline/creatinine, pyridinoline/creatinine, and deoxypyridinoline/creatinine ratios induced by ovx. Tibolone also reduced body weight gain and serum cholesterol level, as has been reported for estrogen. These findings indicate that tibolone prevents reduction in bone mass associated with osteopenia by reducing increased trabecular bone resorption induced by a combination of ovx and a low-Ca diet.

Administration, Oral↗
PubMed1998

The impairment of flow-mediated vasodilatation in obese men with visceral fat accumulation.

BACKGROUND: Obesity has been reported to be associated with coronary artery disease and other atherosclerotic diseases. Recently, evidence has accumulated indicating that intra-abdominal visceral fat accumulation contributes to atherogenesis; however, the mechanism underlying this remains to be determined. This study was undertaken to elucidate whether intra-abdominal visceral fat accumulation impairs vascular endothelial function in obese men. METHODS AND RESULTS: Thirty-eight obese men (body mass index (BMI) > or = 26.0), aged 19-64 y (mean age 37.6 +/- 1.8 y) and 23 age-matched non-obese subjects were examined. According to the ratio of the maximum thickness of preperitoneal fat to the minimum thickness of subcutaneous fat (Pmax/Smin) obtained by longitudinal ultrasound scanning in the subxiphoid region in obese men, we divided obese subjects into two categories; visceral (Pmax/Smin > or = 1; n=23) and subcutaneous type (Pmax/Smin < 1; n=15). To investigate endothelial function, we performed ultrasound measurement of the brachial artery diameter non-invasively both at rest and during reactive hyperaemia in the muscle distal to the brachial artery which causes endothelium-dependent vasodilatation. The brachial diameter change was also measured after sublingual administration of nitroglycerin, which causes endothelium-independent vasodilatation. Flow-mediated diameter (D) increase (%FMD; deltaD/D x 100), in the subjects with visceral type obesity (3.09 +/- 0.43%) was significantly lower than those of the subjects with subcutaneous type obesity and non-obese subjects (7.90 +/- 0.51%, 8.91 +/- 0.44%, respectively, P < 0.01). The magnitude of endothelium-independent vasodilatation by nitroglycerin was similar in all groups. On multiple regression analysis, the Pmax/Smin showed a significant inverse correlation with %FMD. CONCLUSIONS: The subjects with visceral type obesity, rather than those with the subcutaneous type, are associated with impaired flow-mediated endothelium-dependent vasodilatation of the brachial artery.

Adipose Tissue↗