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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 289 records · Page 16Linked to original sources
PubMed1998

Dietary cystine and liver triacylglycerols in rats: effects of dietary lysine and threonine.

Addition of excess cystine to a wheat gluten diet did not alter rat liver triacylglycerols or serum cholesterol. However, if the cystine-enriched diet was supplemented with lysine and threonine, rats accumulate triacylglycerols and show increased serum cholesterol. Increases in hepatic triacylglycerols can be prevented by the further addition of methionine. This diet further increases serum cholesterol. We conclude that accumulation of triacylglycerols in the liver might be due to an increased methionine requirement, induced by the addition of excess cystine, and therefore to choline deficiency.

Amino Acids↗
PubMed1998

A novel second isoenzyme of the human UDP-N-acetylglucosamine:alpha1,3-D-mannoside beta1,4-N-acetylglucosaminyltransferase family: cDNA cloning, expression, and chromosomal assignment.

We isolated a novel cDNA encoding a second isoenzyme of UDP-N-acetylglucosamine:alpha1,3-D-mannoside beta1,4-N-acetylglucosaminyltransferase (GnT-IV; EC 2.4.1.145). The nucleotide and deduced amino acid sequences of the cDNA were homologous to those of the previously cloned human GnT-IV cDNA (63% and 62% identity, respectively). The new cDNA is also confirmed to express GnT-IV activity, suggesting that two isoenzymes of human GnT-IV exist. Although genomic Southern analysis suggested that both genes exist in many mammalian species and the chicken, northern analysis revealed that both genes are expressed in different ways in human tissues. This is the first report concerning the gene family of an N-acetylglucosaminyltransferase in mammals.

Amino Acid Sequence↗
PubMed1998

Low-density induced apoptosis of cortical neurons is inhibited by serum factors.

1. We investigated the survival of neurons under serum-free conditions without any exogenous signal molecules, using primary cultures of rat cerebral cortex. 2. Survival activity, measured with Alamar Blue, showed a cell density dependency under serum-free conditions. 3. The addition of fetal bovine serum suppressed the apoptotic cell death accompanied by DNA-laddering and fragmentation specific in low-density cultures, resulting in the disappearance of the cell density dependency of survival. 4. These findings suggest that serum factors may substitute for endogenous survival factors from cortical neurons in high-density cultures.

Animals↗
PubMed1998

Comparison of short- and long-term effects of betaxolol and timolol on human retinal circulation.

PURPOSE: To determine the short- and long-term effects of betaxolol and timolol on human retinal circulation. METHODS: In a double-masked, randomised, placebo-controlled study we evaluated the effects of both a one-drop application and a twice-daily 2-week application of either topical 0.5% betaxolol hydrochloride or topical 0.5% timolol maleate on the retinal circulation in 12 healthy volunteers. Laser Doppler velocimetry was used to detect changes in the retinal venous blood flow. RESULTS: In both betaxolol- and timolol-treated eyes, intraocular pressure decreased significantly compared with baseline values after both 90 min and 2 weeks. In betaxolol-treated eyes, retinal blood flow did not change significantly after 90 min, but increased significantly (14 +/- 9%; p = 0.02) compared with baseline after 2 weeks. In timolol-treated eyes, retinal blood flow decreased significantly (18 +/- 5%: p = 0.04) compared with baseline after 90 min, and also decreased significantly (14 +/- 6%; p = 0.04) compared with baseline after 2 weeks. CONCLUSIONS: Retinal blood flow increases as a long-term effect of betaxolol and decreases as both a short- and long-term effects of timolol.

Adrenergic beta-Antagonists↗
PubMed1998

Diurnal variation of corneal autofluorescence in normal and diabetic eyes.

PURPOSE: To examine the diurnal variations in corneal autofluorescence in normal and diabetic patients. METHODS: We measured corneal autofluorescence using a fluorophotometer fitted with an anterior segment adapter. Corneal autofluorescence was measured 10 times at 3 min intervals to evaluate the reproducibility of this instrument in 4 eyes of 4 normal subjects. The diurnal variation in corneal autofluorescence was determined by measuring the fluctuations in 10 eyes in 10 normal subjects and one unoperated eye each of 10 patients with proliferative diabetic retinopathy (PDR). We performed five consecutive measurements at 1000, 1130, 1400, 1630 and 1900 hours. The mean value of five measurements, the variation range and the coefficient of variation were analysed. RESULTS: The mean coefficient of variation in the measurement using this instrument was 8.6 +/- 1.0%. In the patients with PDR, the mean corneal autofluorescence value was significantly higher (p < 0.001), the variation range was significantly wider (p < 0.001) and the coefficient of variation was significantly greater (p < 0.01) than in the normal subjects. CONCLUSIONS: The results of this study suggest that corneal autofluorescence changes over the course of a day in patients with diabetes. This may be caused by the breakdown of the blood-aqueous barrier that we reported previously.

Adult↗
PubMed1998

Range of motion of the temporomandibular joint in rheumatoid arthritis: relationship to the severity of disease.

The purpose of this study was to determine the frequency and nature of temporomandibular joint (TMJ) involvement in rheumatoid arthritis (RA) patients with symptoms in this joint, and to investigate the relationship of symptoms to the C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and Steinbrocker stage. Clinical examination of the range of motion of the TMJ was performed in 218 RA patients. In addition, correlations between the maximal mouth opening and the severity of RA were studied. Restriction in opening the mouth (defined as < or = 30 mm movement in the central incisor region from the fully occluded to maximally open positions) was observed in 12.8% of the RA patients (28/218). The CRP, ESR and Steinbrocker stage were all correlated with maximal opening (p < 0.05). There was a positive correlation between the severity of RA and the range of motion of the jaw.

Adult↗
PubMed1998

Additive effects of bovine serum albumin, dithiothreitol, and glycerol on PCR.

The effects of bovine serum albumin, dithiothreitol, and glycerol on PCR were studied. PCR under standard conditions failed the amplification of an enterohemorrhagic E. coli DNA fragment when the boiled bacterial cell lysate was used as the template. The addition of either one of bovine serum albumin, dithiothreitol, or glycerol in the reaction mixture allowed the specific fragment amplification; and the optimum concentrations were as follows: bovine serum albumin, 1 mg/ml; dithiothreitol, 10 mM; and glycerol, 5%. In addition, when all of the three agents were included at the above concentrations, the PCR yield was further increased. The effect of the three-agent mixture was not the template specific. Furthermore, the mixture enabled long PCR over 20 kb when Taq DNA polymerase with 3'-5' exonuclease activity was used for the amplification. Our simple PCR method allows robust PCR independent of template purity or amplification length.

Animals↗
PubMed1998

Prevalence of hepatitis G virus RNA and anti-E2 in a Japanese haemodialysis population.

BACKGROUND: Patients on maintenance haemodialysis (HD) are at greater risk of parenterally transmitted infection with not only A-E hepatitis virus but also with hepatitis G virus (HGV) that has been recovered from patients with non A-E hepatitis. The prevalence of HGV infection in HD patients, which is based on the detection of HGV RNA using reverse transcription-polymerase chain reaction techniques, differs widely between countries. Recently, a new assay has been developed that detects an antibody to the envelope protein (E2) of HGV (anti-E2) that appears to be associated with the loss of HGV RNA from the serum and which may be a useful marker for previous HGV infection. METHODS: To determine the actual prevalence of HGV infection in maintenance HD patients, we examined both HGV RNA and anti-E2 antibody in sera from 200 patients undergoing maintenance HD. RESULTS: Thirty patients (15%) tested positive for HGV RNA, and 14 (7%) tested positive for E2 antibody. Of these, two individuals tested positive for both markers. Overall, 21% of these HD patients had been exposed to HGV. A logistic regression analysis failed to show any clinical feature associated with the detection of HGV RNA. The duration of HD and the presence of HCV RNA were associated with anti-E2. Male gender and HCV RNA were risk factors for the elevation of serum ALT activities. HGV RNA sequences of the patients were not identical to each other. CONCLUSIONS: Our data indicate that HGV infection is prevalent in patients undergoing HD but that liver abnormalities are rare. The nosocomial transmission of HGV in the HD unit was not confirmed.

Aged↗
PubMed1998

Evaluation of changes in sympathetic nerve activity and heart rate in essential hypertensive patients induced by amlodipine and nifedipine.

OBJECTIVE: To compare the effects of amlodipine and nifedipine on heart rate and parameters of sympathetic nerve activity during the acute and chronic treatment periods in order to elucidate their influence on cardiovascular outcome. DESIGN: A randomized and single-blind study. METHODS: We performed 24 h ambulatory electrocardiography and blood pressure monitoring of 45 essential hypertensive inpatients. Plasma and urinary catecholamine levels were measured during the control (pretreatment) period, on the first day (acute period) and after 4 weeks (chronic period) of administration of amlodipine and of short-acting nifedipine or its slow-releasing formulation. The low-frequency and high-frequency power spectral densities and low-frequency: high-frequency ratio were obtained by heart rate power spectral analysis. RESULTS: Blood pressure was significantly and similarly reduced by administrations of amlodipine, short-acting nifedipine and slow-releasing nifedipine during the chronic period. The total QRS count per 24 h, which remained constant during the chronic period of administration of slow-releasing nifedipine and was increased by administration of nifedipine, was decreased by 2.8% by administration of amlodipine. Administration of amlodipine decreased the plasma and urinary norepinephrine levels during the chronic period, whereas the levels were significantly increased by administration of short-acting nifedipine and not changed by administration of slow-release nifedipine. Although low-frequency: high-frequency ratio was increased significantly by administration of short-acting nifedipine and slightly by administration of slow-releasing nifedipine, administration of amlodipine reduced it during the acute and chronic periods. CONCLUSIONS: Administration of amlodipine did not induce an increase in sympathetic nerve activity in essential hypertensive patients during the chronic period, suggesting that beneficial effects on essential hypertension can be expected after its long-term administration. Administration of slow-releasing nifedipine induces milder reflex sympathetic activation than does that of short-acting nifedipine.

Adult↗
PubMed1998

Use of a gastric juice-based PCR assay to detect Helicobacter pylori infection in culture-negative patients.

A gastric juice-based PCR assay was compared with culture, microscopy, and a rapid urease test with specimens from 114 subjects. The PCR and conventional tests were positive for 76 and 62% of the subjects, respectively. The prevalence of gastroduodenal disease and seropositivity for anti-Helicobacter pylori immunoglobulin G were similarly high among conventional-test-positive and PCR-only-positive subjects compared to all-negative ones. The PCR assay is recommended to confirm the H. pylori status of culture-negative peptic-ulcer patients.

Adult↗
PubMed1998

Association between angiotensin II receptor gene polymorphism and serum angiotensin converting enzyme (SACE) activity in patients with sarcoidosis.

BACKGROUND: Serum angiotensin converting enzyme (SACE) is considered to reflect disease activity in sarcoidosis. SACE activity is increased in many patients with active sarcoid lesions. The mechanism for the increased SACE activity in this disease has not been clarified. ACE insertion/deletion (I/D) gene polymorphism has been reported to have an association with SACE levels in sarcoidosis, but no evidence of an association between angiotensin II receptor gene polymorphism and SACE in this disease has been found. A study of the association of angiotensin II receptor gene polymorphisms with sarcoidosis was therefore undertaken. METHODS: ACE (I/D), angiotensin II type 1 receptor (AGTR1), and angiotensin II type 2 receptor (AGTR2) gene polymorphisms were investigated by polymerase chain reaction (PCR) and SACE levels were measured in three groups of patients: those with sarcoidosis or tuberculosis and normal controls. RESULTS: There was no difference in allele frequency of AGTR1 and AGTR2 polymorphism among the three groups. Neither AGTR1 nor AGTR2 polymorphisms were associated with sarcoidosis. SACE activity was higher in patients with sarcoidosis with the AGTR1 A/C genotype than in others. However, this tendency was not detected in patients with tuberculosis. CONCLUSIONS: The AGTR1 allele C is associated with high activity of SACE in patients with sarcoidosis. It is another predisposing factor for high levels of SACE in patients with sarcoidosis and is considered to be an independent factor from the ACE D allele for high levels of SACE in sarcoidosis. This fact could be one of the explanations for the increased SACE activity in sarcoidosis.

Analysis of Variance↗
PubMed1998

Corneal and lens autofluorescence in young insulin-dependent diabetic patients.

To study the early ocular abnormalities in young diabetic patients, corneal and lens autofluorescence was measured by fluorophotometry in 30 eyes of 30 insulin-dependent diabetic patients without retinopathy. The lens [f(l)] and the corneal [f(c)] autofluorescence values in diabetic patients were significantly higher than in controls. In diabetic patients, f(l) was significantly correlated with the duration of diabetes, the f(c) was significantly correlated with the duration of diabetes and the indices of metabolic control, i.e. HbA1c and fructosamine. Our study demonstrated that young diabetic patients clearly had corneal and lens abnormalities before the appearance of overt diabetic retinopathy. The f(c) value might be a good indicator of metabolic control in diabetic patients.

Adolescent↗
PubMed1998

Increased vascular endothelial growth factor production in the lungs of rats with hypoxia-induced pulmonary hypertension.

Vascular endothelial growth factor (VEGF) is a potent mitogenic and permeability factor targeting predominantly endothelial cells. At least two tyrosine kinase receptors, Flk-1 and Flt-1, mediate its action and are mostly expressed by endothelial cells. VEGF and VEGF receptor expression are upregulated by hypoxia in vivo and the role of VEGF in hypoxia-induced angiogenesis has been extensively studied in a variety of disease entities. Although VEGF and its receptors are abundantly expressed in the lung, their role in hypoxic pulmonary hypertension and the accompanying vascular remodeling are incompletely understood. We report in this in vivo study that hypoxia increases mRNA levels for both VEGF and Flk-1 in the rat lung. The kinetics of the hypoxic response differ between receptor and ligand: Flk-1 mRNA showed a biphasic response to hypoxia with a significant, but transient, rise in mRNA levels observed after 9-15 h of hypoxic exposure and the highest levels noted after 3 wk. In contrast, VEGF mRNA levels did not show a significant increase with acute hypoxia, but increased progressively after 1-3 wk of hypoxia. By in situ hybridization, VEGF mRNA was localized predominantly in alveolar epithelial cells with increased signal in the lungs of hypoxic animals compared with controls. Immunohistochemical staining with anti-VEGF antibodies localized VEGF peptide throughout the lung parenchyma and was increased in hypoxic compared with normoxic animals. Furthermore, hypoxic animals had significantly higher circulating VEGF concentrations compared with normoxic controls. Lung vascular permeability as measured by extravasation of Evans Blue dye was not significantly different between normoxic and hypoxic animals, although a tendency for increased permeability was seen in the hypoxic animals. These findings suggest a possible role for VEGF in the pulmonary response to hypoxia.

Animals↗
PubMed1998

The role of NF-kappaB in retinal neovascularization in the rat. Possible involvement of cytokine-induced neutrophil chemoattractant (CINC), a member of the interleukin-8 family.

Hypoxia precedes neovascularization in many retinal diseases that can lead to irreversible vision loss. The transcription factor NF-kappaB is activated by hypoxia and regulates the expression of many genes, including angiogenic factors. The relation between the NF-kappaB activation and the cytokine-induced neutrophil chemoattractant (CINC), a member of the interleukin-8 (IL-8) family, was investigated by immunohistochemistry in a rat model of proliferative retinopathy presumably caused by relative hypoxia. Activated NF-kappaB and CINC immunoreactivity was detected in retinal glial cells in the nonperfused retina and in neovascular cells. Activated NF-kappaB was detected before the CINC staining, and both of these events occurred before the development of neovascularization. The intensity of both activated NF-kappaB and CINC staining remained increased during the development of neovascularization and then declined as neovascularization regressed. In rat retinal glial cells in vitro, dexamethasone, an inhibitor of NF-kappaB activation, prevented the hypoxia-induced increase in the amount of CINC mRNA. Furthermore, CINC induced neovascularization in a rat corneal pocket model. These results suggest that hypoxia-induced activation of NF-kappaB results in CINC production and participates in the induction of retinal neovascularization.

Actins↗
PubMed1998

The relation between the pacing sites in the right ventricular outflow tract and QRS morphology in the 12-lead ECG.

Optimal pace mapping is a good predictor of the appropriate ablation site for idiopathic right ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). We studied the relationship between the RVOT pacing site and QRS morphology in the 12-lead ECG during pacing to find the optimal site more quickly. In 13 patients with idiopathic VT, pacing at 8 sites in the RVOT (free wall, septum, and anterior and posterior regions of upper and lower sites) was performed while 12-lead ECGs were recorded. The R-wave amplitude minus the S-wave amplitude in lead I (RI-SI) and aVF (RavF-SavF) and the transitional zone index (TZI) were compared in the different pacing sites; TZI was defined to examine the transitional zone as a value. The RI-SI was smaller in the anterior region than in the other regions, and the negative RI-SI predicted that the pacing site was in the upper or lower anterior regions. The RavF-SavF was larger in the septum and anterior regions than in the free wall and posterior regions. The TZI was larger in the free wall region than in the septum. From the results, we constructed a flow chart that differentiates the origin of the arrhythmia in the RVOT and a directional guide that indicates the direction from the current mapping site for optimal pace mapping. The results provided an ECG guide for locating the focus of VT originating from the RVOT. These findings may systematically improve the mapping procedure.

Adolescent↗
PubMed1998

A case of cardiac sarcoidosis: significance of ventricular tachycardia originating from the septum.

A 65-year-old woman was admitted for assessment of recurrent tachycardia. Cross-sectional echocardiography showed that the anterobasal portion of the ventricular septum was thin and dyskinetic. An electrophysiologic study revealed ventricular tachycardia, during which marked fragmented potentials could be obtained from the anterior septal aspect of the right ventricle. The site of earliest activation was in the vicinity of the His bundle. A diagnosis of cardiac sarcoidosis was made by based on endomyocardial biopsy combined with the clinical manifestations. Ventricular tachycardia originating from the anterior septum may be an indicator of underlying cardiac sarcoidosis.

Aged↗