Biomedical subjects

K Yasuda

Publications and source records attributed to K Yasuda.

At least 145 records · Page 8Linked to original sources

PubMed2001

Dose-dependent prophylactic effect of nicorandil, an ATP-sensitive potassium channel opener, on intra-operative myocardial ischaemia in patients undergoing major abdominal surgery.

Nicorandil, a nicotinamide nitrate derivative, relaxes vascular smooth muscle and reduces cardiac muscle contractility by increasing membrane potassium conductance, probably by activating ATP-sensitive potassium channels. In this prospective, randomized, double-blind, placebo-controlled clinical study, we examined the dose-dependent prophylactic effect of nicorandil on intra-operative myocardial ischaemia in 248 patients who had pre-operative risk factors for ischaemic heart disease and were undergoing major abdominal surgery. Patients in group HD (n=81) received a bolus dose of nicorandil 0.08 mg kg(-1) and a continuous infusion of 0.08 mg kg(-1) h(-1). Patients in group LD (n=87) received nicorandil 0.04 mg kg(-1) and 0.04 mg kg(-1) h(-1). Patients in the placebo (P) group (n=80) received the same volumes of saline. The patients were monitored with a three-lead clinical ECG monitor with an ST trending device from arrival in the operating theatre to the end of anaesthesia. Intra-operative myocardial ischaemia occurred significantly less frequently in the HD group (one patient, 1.2%) than in the LD (11 patients, 12.6%) and P groups (21 patients, 26.3%) (P<0.01), and in group LD significantly less than in group P (P<0.05). Administration of nicorandil had little effect on the patients' heart rate or arterial pressure. Three patients in group P and none in either treatment group developed myocardial infarction after surgery.

Abdomen↗

PubMed2001

The inhibitory effect of dienogest, a synthetic steroid, on the growth of human endometrial stromal cells in vitro.

Dienogest is a synthetic steroid that has been used as a progestogen in contraceptive pills and is currently being studied for its possible clinical use in the treatment of endometriosis. In this study, we investigated the direct effects of dienogest in differentiation and proliferation of human endometrial stromal cells (ESC) in vitro. After 12 days in the presence of oestradiol (10(-8) mol/l) plus dienogest (10(-6) mol/l), cultured ESC underwent morphological differentiation and produced prolactin, a typical marker for decidualization. By using Northern blot analysis and radioimmunoassay, it was shown that treatment of ESC with oestradiol (10(-8) mol/l) plus dienogest (10(-9) to10(-6) mol/l) led to an increase in the levels of prolactin mRNA and prolactin production in a dose-dependent manner. Additionally, RU-486, a progesterone receptor antagonist, almost completely inhibited dienogest-induced prolactin production. As shown by the thymidine uptake method, there was a dose-dependent inhibition of ESC proliferation with dienogest (P < 0.01, control versus concentrations >10(-7) mol/l). The significant inhibition of ESC proliferation by dienogest (10(-7) mol/l) was partially reversed by RU-486 (10(-6) mol/l). In summary, dienogest directly acts on endometrial tissue in progestogenic response, such as decidualization, increased prolactin production and growth retardation. These data imply that dienogest exerts direct effect in suppressing growth of endometriotic implants.

Cell Division↗

PubMed2001

Isolation, characterization, and expression analysis of zebrafish large Mafs.

Large Maf proteins, which are members of the basic leucine zipper (b-Zip) superfamily, are involved in the determination and control of cellular differentiation. The expression patterns of various vertebrate large Maf mRNAs were described previously. Here, we report the cloning of a novel zebrafish large Maf cDNA, SMaf1 (Somite Maf1), and other zebrafish large Mafs, the N-terminus domains of which possess transactivational activity. We also analyzed the expression patterns of SMaf1 and SMaf2 (Somite Maf2)/Krml2 as well as MafB/Val and c-Maf during zebrafish embryogenesis. In particular, the robust expression of the novel SMaf1 mRNA, which overlapped that of MyoD, in somitic cells during somitogenesis was noteworthy. In addition, the expression patterns of SMaf2 and MafB in the blood-forming regions, and those of c-Maf and MafB in the lens cells showed spatial redundancy, although the temporal appearance of these genes at these sites differed. These data indicate that SMafs may play important roles in somitogenesis, and that Maf proteins may have overlapping and yet specific functions as to the determination and differentiation of cell lineages.

Amino Acid Sequence↗

PubMed2001

Platelet-activating factor acetylhydrolase isoforms I and II in human uterus. Comparisons with pregnant uterus and myoma.

The concentrations of platelet-activating factor (PAF) that possesses the ability to stimulate myometrial contraction are partially regulated by intracellular type of platelet-activating factor acetylhydrolase (PAF-AH) in many tissues. Tissue cytosol contains at least two intracellular PAF-AH, isoforms I and II. To examine the relationship between the activity and isoforms of intracellular PAF-AH in human uterine myometrium and myoma, we assayed the PAF-AH activity and identified the PAF-AH isoforms I and II by Western blot analysis. The intense bands of the alpha2 and ss subunits of PAF-AH isoform I were detected in nonpregnant uterus; however, the specific bands of the alpha1 subunit of PAF-AH isoform I and the PAF-AH isoform II were extremely weak. The levels of the alpha2 and ss subunits and PAF-AH activity in pregnant uterus (37-39 wk gestation) were significantly lower than those in nonpregnant uterus. On the other hand, the level of ss subunit and the PAF-AH activity in myoma were significantly higher than those in nonpregnant uterus. No significant difference was found in the expression of the PAF-AH isoform II among three tissues. These results indicate that the change in the PAF-AH activity observed in pregnant uterus and myoma are due to the lower or higher protein expression of the PAF-AH isoform I, especially the alpha2 and/or ss subunits. The decrease of the uterine PAF-AH activity in the late stage of pregnancy may facilitate the action of PAF to stimulate myometrial contraction.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed2001

Alpha-fetoprotein-producing male breast cancer accompanied with hepatocellular carcinoma: assessment by lectin-affinity profile.

An autopsy case associated with both male breast cancer and hepatocellular carcinoma in which serum alpha-fetoprotein (AFP) was extremely elevated is described. The source of AFP production was investigated. In lectin-affinity chromatography of the patient's serum, concanavalin A (ConA) binding pattern was not consistent with that of hepatocellular carcinoma, and lens culinaris agglutinin A (LCA) affinity indicated a similar pattern to hepatocellular carcinoma. The immunohistochemistry staining for AFP revealed positive reactivity in breast cancer cells, but was negative in hepatocellular carcinoma cells. To the best of our knowledge, there have been no reports of breast cancer exhibiting immunohistochemically positive AFP in breast cancer cells. In the present case, ConA binding test was useful for identification of the source of AFP production. Furthermore, corresponding aggravation of breast cancer to the elevation of AFP suggested the possibility that AFP might enhance breast cancer growth.

Aged↗

PubMed2001

The human pregnane X receptor: genomic structure and identification and functional characterization of natural allelic variants.

The pregnane X receptor (PXR)/steroid and xenobiotic receptor (SXR) transcriptionally activates cytochrome P4503A4 (CYP3A4) when ligand activated by endobiotics and xenobiotics. We cloned the human PXR gene and analysed the sequence in DNAs of individuals whose CYP3A phenotype was known. The PXR gene spans 35 kb, contains nine exons, and mapped to chromosome 13q11-13. Thirty-eight single nucleotide polymorphisms (SNPs) were identified including six SNPs in the coding region. Three of the coding SNPs are non-synonymous creating new PXR alleles [PXR*2, P27S (79C to T); PXR*3, G36R (106G to A); and PXR*4, R122Q (4321G to A)]. The frequency of PXR*2 was 0.20 in African Americans and was never found in Caucasians. Hepatic expression of CYP3A4 protein was not significantly different between African Americans homozygous for PXR*1 compared to those with one PXR*2 allele. PXR*4 was a rare variant found in only one Caucasian person. Homology modelling suggested that R122Q, (PXR*4) is a direct DNA contact site variation in the third alpha-helix in the DNA binding domain. Compared with PXR*1, and variants PXR*2 and PXR*3, only the variant PXR*4 protein had significantly decreased affinity for the PXR binding sequence in electromobility shift assays and attenuated ligand activation of the CYP3A4 reporter plasmids in transient transfection assays. However, the person heterozygous for PXR*4 is normal for CYP3A4 metabolism phenotype. The relevance of each of the 38 PXR SNPs identified in DNA of individuals whose CYP3A basal and rifampin-inducible CYP3A4 expression was determined in vivo and/or in vitro was demonstrated by univariate statistical analysis. Because ligand activation of PXR and upregulation of a system of drug detoxification genes are major determinants of drug interactions, it will now be useful to extend this work to determine the association of these common PXR SNPs to human variation in induction of other drug detoxification gene targets.

Alleles↗

PubMed2001

Laparoscopy-assisted distal gastrectomy for gastric malignant lymphoma.

Although the best treatment for gastric malignant lymphoma remains a controversial matter, surgery is the first choice for localized malignant lymphoma without lymph node metastasis and invasion to the adjacent organ. We report a case of gastric malignant lymphoma that was managed with laparoscopy-assisted distal gastrectomy. A 47-year-old man was referred to our department for management of gastric lymphoma. After preoperative examination revealed a tumor confined to the gastric wall but no lymph node metastasis, we performed laparoscopy-assisted Billroth I gastrectomy. Histopathologic examination confirmed that the tumor was follicular center lymphoma limited to the submucosa with no lymph node metastasis. The postoperative course was good. This is the first reported case of laparoscopic gastrectomy-treated gastric malignant lymphoma. Because it involves minimal access and invasiveness, this procedure may be an effective method of treatment of localized malignant lymphoma of the stomach.

Gastrectomy↗

PubMed2001

Transcriptional control of intestinal cytochrome P-4503A by 1alpha,25-dihydroxy vitamin D3.

It was previously shown that CYP3A4 is induced in the human intestinal Caco-2 cell model by treatment with 1alpha,25-dihydroxy vitamin D3 (1,25-D3). We demonstrate the vitamin D analog, 19-nor-1alpha,25-dihydroxy vitamin D2, is also an effective inducer of CYP3A4 in Caco-2 cells, but with half the potency of 1,25-D3. We report that treatment of LS180 cells, a human intestinal cell line, with 1 to 10 nM 1,25-D3 dose dependently increased CYP3A4 protein and CYP3A4 mRNA expression. CYP3A4- and CYP3A23-promoter-Luciferase reporter constructs transiently transfected into LS180 cells were transcriptionally activated in a dose-dependent manner by 1,25-D3, whereas mutation of the nuclear hormone receptor binding motif (ER6) in the CYP3A4 promoter abrogated 1,25-D3 activation of CYP3A4. Although the CYP3A4 ER6 promoter element has been shown to bind the pregnane X receptor (PXR), this receptor does not mediate 1,25-D3 induction of CYP3A4 because a) PXR is not expressed in Caco-2 cells; b) PXR mRNA expression is not induced by 1,25-D3 treatment of LS180 cells; and c) the ligand binding domain of human PXR was not activated by 1,25-D3. 1,25-D3 uses the vitamin D receptor to induce CYP3A4 because a) the vitamin D receptor (VDR)-retinoid X receptor (RXR) heterodimer binds specifically to the CYP3A4 ER6; b) selective mutation of the CYP3A4 ER6 disrupted the binding of VDR-RXR; and c) reporter constructs containing only three copies of the CYP3A4 ER6 linked to a TK-CAT reporter were activated by 1,25-D3 only in cells cotransfected with a human VDR expression plasmid. These data support the hypothesis that 1,25-D3 and VDR induce expression of intestinal CYP3A by binding of the activated VDR-RXR heterodimer to the CYP3A PXR response element and promoting gene transcription.

Animals↗

PubMed2001

Serine proteases increase oxidative stress in lung cells.

Several serine proteases are directly cytotoxic. We investigated whether the cytotoxic effects of proteases are associated with increased levels of reactive oxygen species (ROS) in cells. We found that treatment of lung fibroblasts or bronchial epithelial cells with relatively high concentrations (0.1--100 U/ml) of neutrophil elastase, trypsin, and Pronase increased ROS levels in the mitochondria and cytoplasm. The protease-induced increase in ROS was associated with oxidative cellular injury as determined by generation of 8-hydroxy-2'-deoxyguanosine and malonaldehyde plus 4-hydroxyalkenal. The protease-induced increase in ROS was not merely due to cell detachment because the proteases also caused an increase in ROS in suspended cells, which precluded attachment to the extracellular matrix. The protease-induced increase in ROS appears to contribute to cytotoxicity because cell death induced by proteases was attenuated by treatment with catalase, a decomposer of H(2)O(2), and accelerated by treatment with aminotriazole, a catalase inhibitor. These results suggest that several proteases increase oxidative stress, indicating a direct interaction between proteases and ROS in mediating cytotoxicity.

Bronchi↗

PubMed2001

Transurethral holmium: YAG laser prostatectomy using a side-firing fiber for bladder outlet obstruction due to benign prostatic enlargement: urodynamic evaluation of surgical outcome.

OBJECTIVES: To prospectively assess the efficacy of transurethral holmium (Ho):YAG laser prostatectomy using a side-firing fiber in patients with bladder outlet obstruction due to benign prostatic enlargement (BPE) from the standpoint of urodynamics. METHODS: 32 male patients with BPE aged 53-83 (mean 69.4) years were operated on. All patients, excluding 3 with urinary retention, were evaluated with the International Prostatic Symptom Score (IPSS), Quality of Life (QOL) score and uroflowmetry up to 12 months postoperatively, and a pressure/flow study was performed before and 3 months after the operation. RESULTS: The total IPSS score, QOL score, average and maximum flow rates improved significantly (p<0.0001) at 12 months postoperatively. In the pressure/flow study, detrusor opening pressure, maximum detrusor pressure, detrusor pressure at maximum flow, minimum urethral opening pressure, and Abrams-Griffiths number decreased significantly (p<0.0001, p = 0.0001, p<0.0001, p = 0.0019 and p<0.0001, respectively) 3 months postoperatively. Detrusor instability disappeared in 12 of 17 patients and remained in 2. CONCLUSIONS: Transurethral Ho:YAG laser prostatectomy was found to be effective for the treatment of bladder outlet obstruction due to BPE.

Aged↗

PubMed2001

Association between serum leptin concentrations and bone mineral density, and biochemical markers of bone turnover in adult men.

Leptin, the product of the ob gene, has been shown to inhibit bone formation in mice. We addressed whether leptin has any role in the regulation of bone mineral density (BMD) in humans. Subjects were 221 adult men with a mean (+/-SD) age and body mass index of 52.1 +/- 8.7 yr and 23.6 +/- 2.8 kg/m2. Serum leptin, carboxyterminal propeptide of type 1 procollagen (PICP; a marker of bone formation), and cross-linked carboxyterminal teleopeptide of type 1 collagen (a marker of bone resorption) were measured by RIA. BMD was assessed by single photon absorptiometry, and total fat mass was determined by bioimpedance analysis. BMD was inversely associated with serum leptin concentrations and total fat mass after adjustment for body weight. PICP, but not cross-linked carboxyterminal teleopeptide of type 1 collagen, was inversely correlated with serum leptin. These results may suggest that an increase in serum leptin reduces bone formation and decreases BMD in adult men. Leptin may be a regulator of BMD in humans.

Adult↗

PubMed2001

Usefulness of thyrotropin (TSH)-releasing hormone test and nocturnal surge of TSH for diagnosis of isolated deficit of TSH secretion.

Six patients with idiopathic isolated deficit of TSH secretion were examined and reported on. Their clinical symptoms and routine biochemical data were unclear and were not specific for hypothyroidism. Serum triiodothyronine, free thyroxine and TSH levels were slightly low or low-normal. Basal metabolic rate and thyroidal (123)I-uptake were also slightly low or low-normal. The response of serum TSH to TRH stimulation was blunted in all patients. No nocturnal surge of serum TSH level could be seen in any of the patients. Empty sella was revealed in three patients, and pituitary microadenoma in one patient via magnetic resolution imaging. Antihuman pituitary cytosol antibody was seen in five patients. Autoimmunity may have played a role in the pathogenesis of idiopathic isolated TSH deficiency. Routine examination of thyroid function cannot easily detect this disease. TSH response to TRH stimulation and nocturnal surge of TSH should be examined when this disease is suspected.

Adult↗

PubMed2001

Adrenal insufficiency after incomplete resection of pituitary macrocorticotropinoma of Cushing's disease: role of high molecular weight ACTH.

A 15-year-old girl with Cushing's disease exhibited adrenal insufficiency following incomplete trans-sphenoidal resection of a large pituitary corticotropinoma, approximately 35 mm in diameter. Within two weeks following surgery, her plasma ACTH level decreased from 42 to 13 pmol/l, while, her plasma cortisol levels and urinary excretion of free cortisol decreased from 607 nmol/l and 1112 nmol/day to 94 nmol/l and 55 nmol/day, respectively. Immunoreactive ACTH was characterized in plasma using Sephadex G-75 column chromatography and measuring ACTH with immunoradiometric assay (IRMA) and radioimmunoassay (RIA) to determine additional peaks, other than the one demonstrated for 1-39 ACTH. In particular, when measured with RIA, a broad peak including the high molecular weight ACTH was detected as well as 1-39 ACTH. The bioactivity of the high molecular weight ACTH in patient plasma was lower than the reference range of 1-39 ACTH, which is determined by the ability of dispersed rat adrenocortical cells to secrete corticosterone. The large pituitary corticotropinoma found in this patient secreted not only 1-39 ACTH but also high molecular weight proopiomelanocortin (POMC)-derived peptides, which could be detected by measuring with IRMA and RIA for ACTH. Based on the results of biological activity and molecular ratios, no positive evidence could be found to support the hypothesis that the high molecular weight ACTH induced any postoperative adrenal insufficiency in this patient. However, based on this study, the possibility of adrenal insufficiency should be carefully monitored, even when post-operative remnant tumor tissue is clearly present in patients with Cushing's disease, accompanied by macrocorticotropinoma.

Adenoma↗

PubMed2001

The Fc gamma receptor genotype as a severity factor for chronic periodontitis in Japanese patients.

BACKGROUND: Functional polymorphisms of immunoglobulin G (IgG) Fc receptors (Fc gamma R) have been shown to be associated with generalized aggressive periodontitis (GAgP) or recurrence of chronic periodontitis (CP) in Japanese patients. The purpose of this study was to evaluate whether Fc gamma R polymorphisms are also associated with severity of CP. METHODS: Fifty Japanese non-smoking patients with severe CP and 39 Japanese non-smoking patients with moderate CP were identified according to established clinical criteria, including measurements of probing depth (PD), clinical attachment level (CAL), and alveolar bone loss (BL). Fc gamma R genotypes for 3 bi-allelic polymorphisms (Fc gamma RIIa-R/H131, Fc gamma RIIIa-158V/F, Fc gamma RIIIb-NA1/NA2) were determined in these CP patients and 64 race-matched, non-smoking healthy controls by means of allele-specific polymerase chain reactions. RESULTS: There was a significant over-representation of Fc gamma RIIIa-158V allele in severe CP patients compared to moderate CP patients (odds ratio 2.03, 95% confidence interval [CI] 1.03-4.01, chi 2 = 4.86, P = 0.028). In addition, we found a strong association between CP severity and Fc gamma R composite genotype comprising Fc gamma RIIIa-158V plus Fc gamma RIIIb-NA2 (severe CP versus moderate CP: odds ratio 4.69, 95% CI 1.52-15.10, chi 2 = 9.35, P = 0.002; severe CP versus healthy controls: odds ratio 4.10, 95% CI 1.62-10.59, chi 2 = 11.13, P = 0.0009). Moreover, CP patients positive for the composite genotype exhibited more severe signs of periodontitis than composite genotype-negative individuals (positive versus negative; mean PD: 3.8 mm versus 3.2 mm, P = 0.005; mean CAL: 4.5 mm versus 3.7 mm, P = 0.005; mean % BL: 37.6% versus 29.9%, P = 0.008). CONCLUSION: Our results document the Fc gamma RIIIa-158V allele and possibly Fc gamma RIIIb-NA2 to be associated with severity of CP in Japanese patients.

Adult↗

PubMed2001

A Japanese case of congenital hyperinsulinism with hyperammonemia due to a mutation in glutamate dehydrogenase (GLUD1) gene.

We describe a Japanese case of neonatal hyperinsulinism due to a de novo mutation (Gly446Asp) in glutamate dehydrogenase gene (GLUD1). A boy suffered from hypoglycemic coma with relative hyperinsulinemia on day 1 after birth, and received subtotal pancreatectomy. Examination of the resected pancreas revealed a diffuse increase in endocrine cells, consistent with 'nesidioblastosis'. He is now 15 years old and has exhibited mild but persistent hyperammonemia, which is a very unique feature of the disorder caused by GLUD1 activating mutations. He has also been suffering from seizures and mental retardation. Thus, GLUD1 mutations can be a cause of congenital hyperinsulinism in Japanese.

Allosteric Regulation↗

PubMed2001

The Pro12 -->Ala substitution in PPAR-gamma is associated with resistance to development of diabetes in the general population: possible involvement in impairment of insulin secretion in individuals with type 2 diabetes.

The allele frequencies for a Pro12-->Ala substitution in peroxisome proliferator-activated receptor-gamma differ among ethnic groups, and its relationship with diabetes and associated diseases is controversial. The prevalence of this polymorphism and its effects on clinical characteristics have now been evaluated with a large number of Japanese individuals with type 2 diabetes (n = 2,201) and normal control subjects (n = 1,212) recruited by 10 institutions located in seven different cities in Japan. The allele frequency for the Ala12 variant was significantly lower in the type 2 diabetic group than in the control group (2.39 vs. 4.13%, P = 0.000054). However, compared with subjects without the Ala12 variant, the diabetic subjects with this variant exhibited a significantly higher serum concentration of total cholesterol (P = 0.001), manifested a reduced capacity for insulin secretion as evaluated by homeostasis model assessment (P = 0.007), and tended to possess a higher level of HbA1c. These data suggest that the Ala12 variant is associated with a reduced risk for the development of diabetes in the general population, but that it may be also a risk factor for insulin deficiency and disease severity in individuals with type 2 diabetes.

Adult↗

PubMed2001

Body fatness and fat distribution as predictors of metabolic abnormalities and early carotid atherosclerosis.

OBJECTIVE: To test the hypothesis that intra-abdominal fat plays a primary role over general adiposity for metabolic abnormalities and atherosclerosis. RESEARCH DESIGN AND METHODS: We cross-sectionally studied 849 Japanese men aged 50.3 +/- 8.5 years (range 20-78) with BMI 23.5 +/- 2.9 kg/m(2). Intimal-medial thickness (IMT) of the carotid artery was measured by ultrasound. General adiposity was assessed by BMI. Waist circumference and waist-to-hip ratio (WHR) were used as a surrogate measure for abdominal fat. Abdominal subcutaneous fat area (ASF) and intra-abdominal fat area (IAF) were measured by computed tomography. Correlations between these measures and carotid IMT were analyzed. The interaction of generalized adiposity (BMI) and IAF in relation to metabolic variables, such as glucose tolerance, insulin resistance, and serum lipids, was also evaluated. RESULTS: BMI, waist circumference, WHR, ASF, and IAF were all correlated with carotid IMT. Adjustment for BMI eliminated the associations between IMT and waist circumference, ASF, and IAF. In contrast, WHR retained a significant correlation with IMT. BMI and IAF were associated with insulin resistance, glucose tolerance, HDL cholesterol, and blood pressure independently of each other. IAF was an independent correlate for serum triglyceride, but BMI was not. CONCLUSIONS: The primary importance of IAF over general adiposity for carotid atherosclerosis was not confirmed. Caution is recommended when using WHR as a measure of abdominal fat. The roles of IAF for metabolic abnormalities may be more limited than conventionally thought. BMI and WHR are simple and better clinical predictors for carotid atherosclerosis versus IAF.

Abdomen↗

PubMed2001

[Analysis of main pigments and other ingredients in lac color product].

The contents of the main pigments and other ingredients in commercial lac color products were determined by HPLC using an RP-18 column with 0.1 mol/L citric acid buffer solution-methanol (16:5) as the mobile phase, and a photodiode array (PDA) detector set at 280 nm and 490 nm. The main pigments were confirmed by PDA and electrospray ionization mass spectrometry. Laccaic acids A, B, C and E were detected in all lac color products, and the ratio of content of laccaic acid A in all products was over 50%. The total contents of laccaic acids A, B and C in lac color food additive products and reagent products were 775-858, 797 and 779 g/kg, respectively. As for the contents of ingredients except pigments in commercial food additive products, the maximum moisture content was about 10%, and ether-soluble substances amounted to 0.5-3.6%.

Azo Compounds↗