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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 253 records · Page 14Linked to original sources
PubMed2000

Synergistic effect of genistein and zinc on bone components in the femoral-metaphyseal tissues of female rats.

The effect of genistein and zinc on bone components in rats was investigated. Femoral-metaphyseal tissues obtained from female rats (4 weeks old) were cultured for 24 h in a medium containing either vehicle or genistein (10(-7)-10(-5) M) in the absence or presence of zinc sulfate (10(-6)-10(-4) M) in vitro. The presence of genistein (10(-6) and 10(-5) M) or zinc (10(-6) and 10(-5) M) caused a significant increase in alkaline phosphatase activity, deoxyribonucleic acid (DNA), and calcium content in the metaphyseal tissues. These increases were significantly enhanced by the combination of each compound. The synergistic effect on bone components was seen in the combination with genistein (10(-6) and 10(-5) M) plus zinc (10(-5) M). Such an effect was completely blocked by the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis. Moreover, the oral administration of genistein (100 and 300 micrograms/kg body weight) or zinc sulfate (1 and 5 mg Zn/kg) to rats for 3 days caused a significant elevation of alkaline phosphatase activity, DNA, and calcium content in the femoral-metaphyseal tissues. These increases were significantly enhanced by the combination of each compound. The synergistic effect was seen in the case of genistein (100 and 300 micrograms/kg) plus zinc (5 mg/kg). These results demonstrate that the anabolic effect of genistein on bone components is synergistically enhanced by zinc in vitro and in vivo. This study further supports the view that the combination of nutritional factors has a potent anabolic effect on bone metabolism.

Alkaline Phosphatase↗
PubMed2000

Intake of fermented soybean (natto) increases circulating vitamin K2 (menaquinone-7) and gamma-carboxylated osteocalcin concentration in normal individuals.

Changes in circulating vitamin K2 (menaquinone-7, MK-7) and gamma-carboxylated osteocalcin concentrations in normal individuals with the intake of fermented soybeans (natto) were investigated. Eight male volunteers were given sequentially fermented soybeans (natto) containing three different contents of MK-7 at an interval of 7 days as follows: regular natto including 775 micrograms/100 g (MK-7 x 1) or reinforced natto containing 1298 micrograms/100 g (MK-7 x 1.5) or 1765 micrograms/100 g (MK-7 x 2). Subsequently, it was found that serum MK-7 and gamma-carboxylated osteocalcin concentrations were significantly elevated following the start of dietary intake of MK-7 (1298 or 1765 micrograms/100 g). Serum undercarboxylated osteocalcin concentrations were significantly decreased by dietary MK-7 (1765 micrograms/100 g) supplementation. Moreover, the changes in serum MK-7 level with the frequency of dietary natto intake were examined in 134 healthy adults (85 men and 39 women) without and with occasional (a few times per month), and frequent (a few times per week) dietary intake of regular natto including MK-7 (775 micrograms/100 g). Serum MK-7 and gamma-carboxylated osteocalcin concentrations in men with the occasional or frequent dietary intake of natto were significantly higher than those without any intake. The present study suggests that intake of fermented soybean (natto) increases serum levels of MK-7 and gamma-carboxylated osteocalcin in normal individuals.

Adult↗
PubMed2000

Clinical and pathological features of accessory valve tissue.

BACKGROUND: Accessory valve tissue is a rare congenital cardiac malformation causing a variety of clinical features. We describe our experience with the surgical treatment of accessory valve tissue to clarify clinical and pathological features of this anomaly. METHODS: Between December 1990 and February 1999, 11 children underwent resection of accessory valve tissue together with repair of coexisting intracardiac malformations. Eight patients had accessory tricuspid valve, while 3 had accessory mitral valve tissue. Associated intracardiac malformations included tetralogy of Fallot in 6 patients, transposition of the great arteries in 3, coarctation complex in 1, and ventricular septal defect in 1. RESULTS: Accessory valve tissue was completely resected in all but 1 patient with accessory mitral valve and transposition of the great arteries. As total resection of the accessory valve tissue through the pulmonary artery was unsuccessful, partial resection and bidirectional Glenn shunt operation was performed instead of arterial switch operation in this patient. CONCLUSIONS: The clinical signs and symptoms of accessory valve tissue vary according to its location and coexisting cardiac malformations. Congenital heart surgeons should be familiar with the clinical and pathological features of accessory valve tissue, so as not to overlook it during operation.

Cardiac Catheterization↗
PubMed2000

Spectrophotometric assay for serum platelet-activating factor acetylhydrolase activity.

We developed a spectrophotometric assay for serum platelet-activating factor acetylhydrolase (PAF-AH, EC 3.1.1.47.) activity using a platelet-activating factor (PAF) analogue with a 4-nitrophenyl group as substrate. PAF-AH hydrolyzes the sn-2 position of the substrate ¿1-myristoyl-2-(p-nitrophenylsuccinyl)phosphatidylcholine, producing p-nitrophenyl succinate. This liberation was spectrophotometrically monitored and the activity determined from the change in absorption. The assay does not require radioisotopes and is applicable to an automatic analyzer. Utilizing this assay with an automatic analyzer, it is possible to measure the activities of thousands of samples in a few hours with excellent precision (CV 0.5%, n=30) and high correlation (r=0.979, n=100) with the results of a conventional radioisotopic assay. The assay should be particularly useful for clinical diagnostics.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Cyclic malyl anthocyanins in Dianthus caryophyllus.

3,5-Di-O-(beta-glucopyranosyl) pelargonidin 6''-O-4,6'''-O-1-cyclic malate and a previously reported cyanidin equivalent, 3,5-di-O-(beta-glucopyranosyl) cyanidin 6''-O-4,6'''-O-1-cyclic malate were identified from petals of deep pink and red-purple flower cultivars of Dianthus caryophyllus, respectively.

Anthocyanins↗
PubMed2000

Direct IFNluence of interferon-gamma on proliferation and cell-surface antigen expression of non-small cell lung cancer cells.

In order to clarify the anti-tumor activity of IFN-gamma, we investigated the direct IFNluence of IFN-gamma on both the growth and cell-surface antigen expression of tumor cells. In the present study, four human lung cancer cell lines were used; two squamous cell lines (QG-56, QG-95) and two adenocarcinoma cell lines (PC-9, PC-12). In all four tumor cell lines, mutations were detected in exon 7 of the p53 gene by a PCR-FSSCP analysis. The proliferation of QG-56 or QG-95 was inhibited by IFN-gamma in a dose-dependent manner with about 70% inhibition at 1000 JRU/ml while that of PC-9 was slightly inhibited with maximally 25% inhibition at 1000 JRU/ml. The growth of PC-12 was not inhibited at all. In QG-56, QG-95 and PC-9, the fraction of cells in G1 phase increased while the fractions of cells in both S and G2/M phases decreased after exposure to IFN-gamma (200 JRU/ml) for 72 h. The growth inhibition by long-term exposure to IFN-gamma was irreversible in QG-56. After culture in the presence of IFN-gamma (200 JRU/ml) for 14-16 days, tumor cells were examined for expression of various antigens, including HLA-class I, HLA-class II, and CEA. In all cell lines but PC-12, 100% of cells expressed HLA-class I after incubation with IFN-gamma. Both HLA-class II and CEA were also induced in those cell lines. The proportion of HLA-class II-positive cells or that of CEA-positive cells varied among the cell lines. Of the three antigens, the degree of HLA-class II expression paralleled that of growth inhibition by IFN-gamma treatment. These results suggested that in various function of IFN-gamma against tumor cells, the anti-proliferative effect might be closely linked with the induction of HLA-class II probably through a similar posttranscriptional process, independent of the function of p53 gene.

Antigens, Surface↗
PubMed2000

Left ventricular systolic dysfunction during exercise and dobutamine stress in patients with hypertrophic cardiomyopathy.

OBJECTIVES: We sought to characterize stress-induced left ventricular systolic dysfunction in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND: Myocardial ischemia and diastolic dysfunction occur in patients with HCM. We hypothesized that, in the setting of transient myocardial ischemia, left ventricular systolic dysfunction occurs during exercise and dobutamine stress. METHODS: We studied 39 patients with HCM but without obstructive symptoms at rest or coronary artery disease. A continuous ventricular function monitor equipped with cadmium telluride detectors (VEST) was used to evaluate left ventricular function during supine bicycle ergometer exercise. Dobutamine stress echocardiography (DSE) was also performed. The left ventricular ejection fraction (LVEF) and regional wall motion were determined from echocardiographic images. RESULTS: Changes in the LVEF correlated between exercise and dobutamine stress (r = 0.643, p < 0.0001). The LVEF decreased more than 5% at peak exercise in 17 of patients (group II), while the other patients had normal responses (group I). New regional wall motion abnormalities during dobutamine infusion were detected in 18 of 110 (16.4%) segments in group I and 42 of 85 (49.4%) segments in group II. Decreased or unchanged regional wall motion occurred more frequently in hypertrophied segments than in nonhypertrophied segments (p < 0.0001). There were significant inverse correlations between the LVEF responses during both stresses and the number of abnormal segments noted during dobutamine stress in all patients (VEST: p < 0.005; DSE: p < 0.0005). Signs of left ventricular obstruction were observed in 11 of 39 patients during DSE. However, there was no significant correlation between the LVEF response and the dobutamine-induced left ventricular pressure gradient. CONCLUSIONS: Exercise-induced systolic dysfunction occurred in 50% of patients with HCM. In these patients, regional wall motion abnormalities were present in hypertrophied segments.

Adult↗
PubMed2000

The spatial location of impingement in total hip arthroplasty.

Impingement between acetabular and femoral components produces wear debris and results in abnormal loads on the edge of the implant. To characterize further the spatial location of impingement and the design and alignment factors associated with impingement, we reviewed 111 retrieved acetabular components from a single manufacturer. The location of impingement in the pelvis was determined by combining the location of impingement in the retrieved implants and the spatial orientation of the acetabular components measured from available radiographs. Evidence of impingement was identified in 39% of the retrieved implants and involved the posterior portion of the acetabulum in all cases. Posterior impingement was probably the result of femoral extension and external rotation, a motion that occurs during the toe-off phase of the gait cycle. Cups with impingement were more anteverted than those without impingement (P = .016). There was a significant inverse association between impingement and the size of the femoral head, and the mean head-to-neck diameter ratio for implants with impingement was smaller than that for implants without impingement (P < .0001). Factors that appear to be associated with impingement include i) excessive cup anteversion combined with posterior positioning of the extended rim and ii) femoral components with relatively small head-to-neck diameter ratio.

Adult↗
PubMed2000

Construction and characterization of phage libraries displaying artificial proteins with random sequences.

Three phage libraries, PL1, PL2, and PL3, displaying artificial proteins with random sequences were constructed. The artificial proteins, which are model of ancestral proteins, are derivatives of the 25 kinds of random proteins with about 140 amino acid residues produced via random mutagenesis and combinatorial recombination. The random proteins were displayed on the surface of filamentous bacteriophage as fusion protein with the pIII coat protein at an estimated average number on the phage particles in PL1, PL2, and PL3 of 0.32, 0.32, and 0.08, respectively. Each library was shown to express 10(5) to 10(6) kinds of random proteins. With the phage libraries displaying long random peptides, we now have an effective selection system to observe in vitro evolution of new functional proteins from artificial proteins with random sequences.

Journal Article↗
PubMed2000

Stimulatory effect of regucalcin on proteolytic activity is impaired in the kidney cortex cytosol of rats with saline ingestion.

The effect of regucalcin (RC) on neutral proteolytic activity in the cytosol of rat kidney cortex was investigated. Proteolytic activity was significantly increased by the presence of RC (0.01-0.10 microM) in the enzyme reaction mixture. This increase was completely abolished by the addition of anti-RC monoclonal antibody (150 ng/ml). When the renal cortex cytosol was incubated without RC addition, the degradation of globin of substrate was demonstrated by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. This degradation was clearly inhibited by the addition of anti-RC antibody (150 ng/ml), indicating that protein degradation results partly from the cytosolic endogenous RC. Meanwhile, proteolytic activity was significantly decreased in the renal cortex cytosol of rats with saline ingestion for 2, 7, and 14 days. The effect of RC (0.1 microM) in increasing proteolytic activity was weakened in the kidney cortex cytosol of saline-ingested rats. The present study suggests that endogenous RC plays a role in the activation of proteases in the renal cortex cytosol, and that the RC effect is impaired in saline-ingested rats.

Animals↗
PubMed2000

Role of endogenous regucalcin in protein tyrosine phosphatase regulation in the cloned rat hepatoma cells (H4-II-E).

Regucalcin, a regulatory protein of Ca2+ signaling, is mainly present in liver cells. The role of regucalcin in hepatoma cells, however, has not been clarified. The role of endogenous regucalcin in the regulation of protein tyrosine phosphatase activity in the cloned rat hepatoma cells (H4-II-E) was investigated. Hepatoma cells were cultured for 3 days in a medium containing serum (10% fetal bovine serum). After subconfluency, the cells were used for the assay of protein phosphatase activity toward phosphotyrosine. The expression of regucalcin in hepatoma cells was detected by Western blotting using anti-regucalcin antibody. Protein tyrosine phosphatase activity was exhibited in the cytosol of hepatoma cells. The enzyme activity in the cytosol of hepatoma cells was significantly elevated by the addition of calcium chloride (10(-6)-10(-4) M) in the reaction mixture. This elevation was completely blocked by the addition of trifluoperazine (TFP: 2.5 x 10(-6) M), an antagonist of calmodulin. The addition of regucalcin (10(-7) M) caused a complete inhibition of the calcium (10(-4) M)-increased enzyme activity. The presence of anti-regucalcin monoclonal antibody (25, 50, and 100 ng/ml) in the enzyme reaction mixture produced a significant increase in protein tyrosine phosphatase activity in the cytosols of hepatoma cells and normal liver cells. This increase was completely prevented by regucalcin addition. The effect of antibody (50 ng/ml) in elevating the enzyme activity was partly inhibited by vanadate (10(-4) M). Protein tyrosine phosphatase activity was significantly elevated by the culture with Bay K 8644, a Ca2+-channel agonist. This increase was blocked by TFP addition in the enzyme reaction mixture, and it was enhanced in the presence of anti-regucalcin antibody. The present study demonstrates that regucalcin is expressed in hepatoma cells (H4-II-E), and that the protein may have an inhibitory effect on Ca2+/calmodulin-dependent protein tyrosine phosphatase activity in the cells.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2000

Stimulatory effect of genistein and daidzein on protein synthesis in osteoblastic MC3T3-E1 cells: activation of aminoacyl-tRNA synthetase.

The effect of genistein and daidzein on protein synthesis in osteoblastic MC3T3-E1 cells in vitro was investigated to determine a cellular mechanism by which the isoflavones stimulate bone formation. Cells were cultured for 48 h in alpha-minimal essential medium containing either vehicle, genistein (l0(-7) - 10(-5) M) or daidzein (10(-7) - 10(-5) M). The 5,500 g supernatant of cell homogenate was used for assay of protein synthesis with [3H]leucine incorporation in vitro. The culture with genistein or daidzein caused a significant elevation of protein synthesis in the cell homogenate. The effect of genistein ( 10(-5) M) or daidzein ( 10(-5) M) in elevating protein synthesis was significantly prevented, when cells were cultured for 48 h in a medium containing either actinomycin D (10(-7) M) or cycloheximide (10(-6) M) in the absence or presence of isoflavones. Moreover, when genistein (10(-7) 10(-5) M) or daidzein (10(-6) and 10(-5) M) was added to the reaction mixture containing the cell homogenate obtained from osteoblastic cells cultured without isoflavone, protein synthesis was significantly raised. This increase was markedly blocked by the addition of cycloheximide (10(-7) M). In addition, [3H]leucyl-tRNA synthetase activity in the cytosol of osteoblastic cells was significantly increased by the addition of genistein (10(-6) and 10(-5) M) or daidzein (10(-5) M) into the enzyme reaction mixture. The present study demonstrates that genistein or daidzein can stimulate protein synthesis in osteoblastic MC3T3-E1 cells. The isoflavones may have a stimulatory effect on osteoblastic bone formation due to increasing protein synthesis.

3T3 Cells↗
PubMed2000

Eotaxin in induced sputum of asthmatics: relationship with eosinophils and eosinophil cationic protein in sputum.

BACKGROUND: Eosinophilic inflammation is a crucial aspect of allergic diseases such as bronchial asthma. An eosinophil-active chemokine, eotaxin, may play a role in the pathogenesis of the tissue eosinophilia accompanying asthma. METHODS: Induced sputa were obtained from 53 patients with atopic asthma and six healthy subjects, and the concentration of eotaxin in the sputum was measured by ELISA. We investigated whether the sputum content of eotaxin is related to 1) asthma status or corticosteroid therapy, and 2) other sputum indices, including percentage of eosinophils and concentration of eosinophil cationic protein (ECP). RESULTS: The patients with stable or unstable asthma showed significantly higher concentrations of sputum eotaxin than the normal controls. The level of sputum eotaxin demonstrated a positive correlation with the percentage of eosinophils in stable asthmatics not receiving corticosteroid therapy, but not in stable patients treated with corticosteroids, or in unstable patients. Sputum eotaxin demonstrated a positive correlation with ECP in asthmatic patients who were either in a stable state or not receiving steroid therapy. CONCLUSIONS: The elevated level of eotaxin detected in association with increased eosinophils and ECP in the sputum of asthmatics suggests that eotaxin is involved in the pathogenesis of eosinophilic airway inflammation. The relationship of eotaxin to airway eosinophilia may be modified by the stability status of asthma and corticosteroid therapy.

Adult↗