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Biomedical subjects

Y Yazaki

Publications and source records attributed to Y Yazaki.

At least 631 records · Page 35Linked to original sources
PubMed1993

Plasma 19-hydroxyandrostenedione is elevated in patients with high renin essential hypertension.

OBJECTIVES: We have reported that 19-hydroxyandrostenedione (19-OH-A-dione) functions as an amplifier of the sodium-retaining and hypertensive action of aldosterone. We therefore measured 19-hydroxyandrostenedione in hypertensive patients. PATIENTS AND MEASUREMENTS: We studied 53 normal male control subjects and 63 male patients with essential hypertension (48 patients with normal renin essential hypertension and 15 patients with high renin essential hypertension). Plasma 19-OH-A-dione levels were measured by RIA. RESULTS: Plasma 19-OH-A-dione concentrations in control subjects and patients with normal and high renin essential hypertension were 115 +/- 46 (mean +/- SD), 112 +/- 49 and 201 +/- 79 pmol/l, respectively. Patients with high renin essential hypertension showed significantly higher 19-OH-A-dione concentrations than did control subjects. The evaluation of the correlation between plasma 19-OH-A-dione concentrations and plasma renin activity revealed that plasma 19-OH-A-dione concentrations in hypertensive subjects rose gradually with an increase in plasma renin activity. Therefore, a significant correlation was found between plasma renin activity and plasma 19-OH-A-dione (r = 0.586, P < 0.001). In contrast, in control subjects, no significant correlation was found between plasma renin activity and plasma 19-OH-A-dione (r = 0.059, P > 0.05). CONCLUSIONS: The secretion of 19-OH-A-dione from the adrenal cortex is under the control of the renin-angiotensin system in hypertensives but not in normotensives.

Adult↗
PubMed1993

Long QT syndrome with insulin-dependent diabetes mellitus: contiguous gene syndrome on chromosome 11p.

Long QT syndrome (Romano-Ward syndrome) and insulin-dependent diabetes mellitus (IDDM) have been documented as being linked with gene(s) on chromosome 11p although concurrence of the two disorders has not been reported. Our case is a 13-year-old boy with Romano-Ward syndrome accompanied by IDDM. The long QT syndrome seemed to be transmitted in an autosomal-dominant mode because the Q-T intervals of his father and paternal grandfather were longer than normal. There was no family member with an abnormally high level of blood glucose except the patient. The human leucocyte antigen (HLA) haplotypes of the patient and the father were DR4/DR9 and DR2/DR9, respectively. This study suggests that in our patient IDDM, as well as Romano-Ward syndrome, is linked with chromosome 11p in the presence of HLA-DR4. The results support the previous study that chromosome 11p encodes a gene implicated in HLA-DR4-dependent diabetes susceptibility.

Child↗
PubMed1993

Expression of GLUT-4 glucose transporter in unweighted soleus muscle of normal and STZ-induced diabetic rats.

Effects of 6 days of hindlimb suspension on expression of glucose transporters were studied in the skeletal muscle of nondiabetic and streptozotocin-induced diabetic rats. Although total membrane protein recovered from soleus muscles tended to decrease with suspension, GLUT-4 protein concentration (amount per gram membrane protein) was increased by 66 and 91% compared with weight-bearing control in nondiabetic and diabetic rats, respectively. Therefore, the amount of GLUT-4 protein in whole soleus muscle did not decrease with the hindlimb suspension in normal and diabetic rats. In contrast, hindlimb suspension decreased GLUT-4 mRNA amount in whole soleus muscle by 47 and 27% in nondiabetic and diabetic rats, respectively. Thus the GLUT-4 protein-to-GLUT-4 mRNA ratio was increased 2.1-fold in nondiabetic and 1.4-fold in diabetic rats. The extensor digitorum longus muscle, which generally shows little response to unweighting, exhibited no such changes. These results suggest that the amount of GLUT-4 glucose transporter in the unweighted soleus muscle was maintained via a translational and/or posttranslational mechanism in nondiabetic rats as well as in streptozotocin-induced diabetic rats under the condition of reduced weight-bearing activity.

Animals↗
PubMed1993

Ductus arteriosus. Advanced differentiation of smooth muscle cells demonstrated by myosin heavy chain isoform expression in rabbits.

BACKGROUND: The closure of the ductus arteriosus (DA) is one of the most striking cardiovascular events that occur at birth. It has been attributed to oxygenation and intrinsic prostaglandins. However, selective constriction of DA suggests the presence of highly specialized contractile mechanisms in DA. We previously reported that smooth muscle myosin heavy chain isoforms, SM1 and SM2, are molecular markers for smooth muscle differentiation because of their unique expression pattern during vascular development. SM1 and SM2 are generated from a single gene through developmentally regulated alternative RNA splicing; SM1 is expressed in almost all stages of differentiation of the vascular smooth muscles, but SM2 is found only after birth. METHODS AND RESULTS: Immunohistochemistry was performed to study the expression of the different types of myosin heavy chain isoforms in DA of fetal and neonatal rabbits. Electron microscopic examinations were also carried out to demonstrate ultrastructural characteristics of ductus muscles. We found that SM2 is expressed before birth in the medial layer of DA, indicating advanced differentiation of smooth muscle cells in DA. The exact location of immunoreactivity for SM2 was in the smooth muscle cell of the medial layer of DA. Immunoreactivity for SM1, however, was not different for DA and adjacent great arteries. Transmission electron microscopy demonstrated greater amounts of myofilaments in medial smooth muscles of DA than those of aorta. CONCLUSIONS: These results indicate that smooth muscles in DA are more differentiated than those in other arteries, which may be one of the cellular mechanisms responsible for the unique closure of DA at birth.

Actin Cytoskeleton↗
PubMed1993

Human smooth muscle myosin heavy chain isoforms as molecular markers for vascular development and atherosclerosis.

Smooth muscle myosin heavy chains (MHCs) exist in multiple isoforms. Rabbit smooth muscles contain at least three types of MHC isoforms: SM1 (204 kD), SM2 (200 kD), and SMemb (200 kD). SM1 and SM2 are specific to smooth muscles, but SMemb is a nonmuscle-type MHC abundantly expressed in the embryonic aorta. We recently reported that these three MHC isoforms are differentially expressed in rabbit during normal vascular development and in experimental arteriosclerosis and atherosclerosis. The purpose of this study was to clarify whether expression of human smooth muscle MHC isoforms is regulated in developing arteries and in atherosclerotic lesions. To accomplish this, we have isolated and characterized three cDNA clones from human smooth muscle: SMHC94 (SM1), SMHC93 (SM2), and HSME6 (SMemb). The expression of SM2 mRNA in the fetal aorta was significantly lower as compared with SM1 mRNA, but the ratio of SM2 to SM1 mRNA was increased after birth. SMemb mRNA in the aorta was decreased after birth but appeared to be increased in the aged. To further examine the MHC expression at the histological level, we have developed three antibodies against human SM1, SM2, and SMemb using the isoform-specific sequences of the carboxyl terminal end. Immunohistologically, SM1 was constitutively positive from the fetal stage to adulthood in the apparently normal media of the aorta and coronary arteries, whereas SM2 was negative in fetal arteries of the early gestational stage. In human, unlike rabbit, aorta or coronary arteries, SMemb was detected even in the adult. However, smaller-sized arteries, like the vasa vasorum of the aorta or intramyocardial coronary arterioles, were negative for SMemb. Diffuse intimal thickening in the major coronary arteries was found to be composed of smooth muscles, reacting equally to three antibodies for MHC isoforms, but reactivities with anti-SM2 antibody were reduced with aging. With progression of atherosclerosis, intimal smooth muscles diminished the expression of not only SM2 but also SM1, whereas alpha-smooth muscle actin was well preserved. We conclude from these results that smooth muscle MHC isoforms are important molecular markers for studying human vascular smooth muscle cell differentiation as well as the cellular mechanisms of atherosclerosis.

Aging↗
PubMed1993

Expression of intercellular adhesion molecule-1 in murine hearts with acute myocarditis caused by coxsackievirus B3.

A cell-mediated autoimmune mechanism has been strongly implicated in the pathogenesis of viral myocarditis. Using a murine model of myocarditis caused by coxsackievirus B3 (CVB3), we previously reported that the heart is infiltrated first by natural killer cells, which express a cytolytic factor, perforin, and then by activated T cells. This action may play an important role in the pathogenesis of the observed myocardial cell damage. Cell-cell contact and adhesion is required in immune responses, and intercellular adhesion molecule-1 (ICAM-1), which is a ligand for lymphocyte function-associated antigen-1 (LFA-1), plays an important role in this process. To investigate the essential role of the ICAM-1/LFA-1 pathway in the cell-mediated cytotoxicity involved in viral myocarditis, we examined by immunofluorescence the expression of ICAM-1 in murine hearts with acute myocarditis caused by CVB3. We also evaluated the induction of ICAM-1 in cultured cardiac myocytes treated with cytokines by immunofluorescence and Northern blot hybridization. Furthermore, we analyzed the effects of in vivo administration of anti-ICAM-1 mAbs on the inflammation associated with acute viral myocarditis. We found that CVB3-induced murine acute myocarditis resulted in enhanced expression of ICAM-1 in myocardial cells. The expression of ICAM-1 in myocardial cells could be induced in vitro by IFN-gamma and TNF-alpha, which were shown to be synthesized by the infiltrating cells. In vivo treatment with F(ab')2 fragments of an anti-ICAM-1 mAb significantly reduced the myocardial inflammation induced by CVB3. These data strongly suggest that the expression of ICAM-1 in myocardial cells plays a critical role in the cell-mediated cytotoxicity involved in acute viral myocarditis.

Acute Disease↗
PubMed1993

Macrophage colony-stimulating factor regulates both activities of neutral and acidic cholesteryl ester hydrolases in human monocyte-derived macrophages.

Macrophage colony-stimulating factor (M-CSF) regulates cholesterol metabolism in vivo and in vitro. We studied the effects of M-CSF on enzyme activities of acidic cholesteryl ester (CE) hydrolase, neutral CE hydrolase, and acyl-coenzyme A:cholesterol acyltransferase (ACAT), all of which are involved in cellular cholesterol metabolism in macrophages. During the differentiation of monocytes to macrophages, these enzyme activities were induced and further enhanced in response to M-CSF. M-CSF (100 ng/ml) enhanced acidic and neutral CE hydrolase and ACAT activities by 3.2-, 4-, and 2.3-fold, respectively, in the presence of acetyl LDL. The presence of acetyl LDL influenced these enzyme activities. ACAT and acidic CE hydrolase activities were increased and neutral CE hydrolase activity was decreased, indicating that these enzymes are regulated by intracellular cholesterol enrichment. M-CSF increased the ratios of acidic CE hydrolase to ACAT activity and of neutral CE hydrolase to ACAT activity. The results suggest that M-CSF enhances net hydrolysis of CE by stimulating the two CE hydrolases to a greater extent than ACAT, and M-CSF may reduce the rate of atherogenesis.

Base Sequence↗
PubMed1993

Disruption of cytoskeletal structures mediates shear stress-induced endothelin-1 gene expression in cultured porcine aortic endothelial cells.

Hemodynamic shear stress alters the architecture and functions of vascular endothelial cells. We have previously shown that the synthesis of endothelin-1 (ET-1) in endothelial cells is increased by exposure to shear stress. Here we examined whether shear stress-induced alterations in cytoskeletal structures are responsible for increases in ET-1 synthesis in cultured porcine aortic endothelial cells. Exposure of endothelial cells to 5 dyn/cm2 of low shear stress rapidly increased monomeric G-actin contents within 5 min without changing total actin contents. The ratio of G- to total actin, 54 +/- 0.8% in quiescent endothelial cells, increased to 87 +/- 4.2% at 6 h and then decreased. Following the disruption of filamentous (F)-actin into G-actin, ET-1 mRNA levels in endothelial cells also increased within 30 min and reached a peak at 6 h. The F-actin stabilizer, phalloidin, abolished shear stress-induced increases in ET-1 mRNA; however, it failed to inhibit increases in ET-1 mRNA secondary to other stimulants. This indicates that shear stress-induced increases in ET-1 mRNA levels may be mediated by the disruption of actin fibers. Furthermore, increases in ET-1 gene expression can be induced by actin-disrupting agents, cytochalasin B and D. Another cytoskeleton-disrupting agent, colchicine, which inhibits dimerization of tubulin, did not affect the basal level of ET-1 mRNA. However, colchicine completely inhibited shear stress- and cytochalasin B-induced increases in ET-1 mRNA levels. These results suggest that shear stress-induced ET-1 gene expression in endothelial cells is mediated by the disruption of actin cytoskeleton and this induction is dependent on the integrity of microtubules.

Actins↗
PubMed1993

Cloning and increased expression with fructose feeding of rat jejunal GLUT5.

We have isolated a clone from the rat jejunum cDNA library using a fragment of human GLUT5 cDNA as a probe. The coding region of this clone shares 80% nucleotide and 81% amino acid identity with human GLUT5 and is thus termed rat GLUT5 cDNA. Rat GLUT5 mRNA exhibited a tissue distribution very similar to that of human GLUT5, with the highest levels in the jejunum, but was not detected in fat, muscle, or testis on Northern blot analysis. The antipeptide antibody raised against the C-terminal domain of rat GLUT5 protein specifically recognized a rat jejunal protein with an apparent mol wt of 60,000 on immunoblots. The amount of GLUT5 mRNA and protein in the jejuni of rats fed a fructose-enriched diet (50%, wt/wt) for 3 days were increased 2.5- and 6-fold, respectively, compared to those of rats fed standard rat chow, whereas those of rats fed a starch-enriched diet (50%, wt/wt) were not altered. Similarly, GLUT5 mRNA and protein in the jejunum were increased 5- and 8-fold, respectively, after 15 days of fructose feeding. Thus, an increase in fructose absorption up-regulates GLUT5 expression in the jejunum. These results are consistent with the notion that GLUT5 plays a major role in fructose absorption in the small intestine.

Amino Acid Sequence↗
PubMed1993

19-Hydroxyandrostenedione amplifies the hypertensive action of mineralocorticoids in rats.

We have reported that 19-hydroxyandrostenedione (19-OH-A-dione) amplifies the sodium-retaining action of aldosterone. To evaluate whether it also amplifies the hypertensive action of small doses of aldosterone, mononephrectomized rats were given 0.5 mg aldosterone, 10 mg 19-OH-A-dione or a combination of both once a week for 19 weeks, and changes in blood pressure were evaluated. Rats were given 154 mmol NaCl/l to drink. The blood pressure of controls, rats given aldosterone alone, 19-OH-A-dione alone or a combination of both in week 19 were 137 +/- 4 (S.E.M.), 146 +/- 7, 147 +/- 4 and 191 +/- 8 mmHg respectively. The blood pressure of rats given the combination was significantly higher than any of the other three groups. These results indicate that 19-OH-A-dione amplifies the hypertensive action of aldosterone and may be considered a potent hypertensive agent in the presence of aldosterone. To evaluate whether 19-OH-A-dione amplifies the hypertensive action of small doses of deoxycorticosterone acetate (DOCA), another experiment was carried out in which similar rats were given 5 mg DOCA or a combination of 5 mg DOCA and 10 mg 19-OH-A-dione once a week for 8 weeks. The blood pressure of controls, rats given DOCA alone and a combination of DOCA and 19-OH-A-dione in week 8 were 139 +/- 5, 166 +/- 7 and 208 +/- 12 mmHg respectively. The blood pressure of rats given a combination of DOCA and 19-OH-A-dione was significantly higher than that of control rats or the rats given DOCA alone. These results indicate that 19-OH-A-dione can also amplify the hypertensive action of DOCA. It is concluded that 19-OH-A-dione amplifies the hypertensive action of mineralocorticoids as well as the sodium-retaining action of aldosterone.

Aldosterone↗
PubMed1993

Sequence variations of the glucokinase gene in Japanese subjects with NIDDM.

Mutations in the glucokinase gene have been identified recently in patients with maturity-onset diabetes of the young, a subtype of NIDDM. The proposed role of glucokinase as a glucose sensor, combined with the low insulin response to glucose found in most Japanese with NIDDM, prompted us to speculate that mutations in the glucokinase gene might be one of the major causes of NIDDM in Japanese subjects. To determine the prevalence of mutations and sequence variations in the glucokinase gene, we screened all 12 exons of the glucokinase gene, including exon/intron junctions, by polymerase chain reaction followed by single-strand conformation polymorphism in 209 Japanese NIDDM subjects. In addition to the mutation in exon 7, which substituted Arg (AGG) for Gly (GGG) at codon 261 (10), a silent mutation of Pro (CCC-->CCG) in exon 4 at codon 145 and several new sequence variations in intervening sequences and the 5'-untranslated region of exon 1 beta (beta-cell-specific exon 1) were identified. Because we identified only one subject who had a structurally abnormal glucokinase molecule, we conclude that the prevalence of structural mutations in the glucokinase gene responsible for NIDDM appears to be rare among Japanese patients. To our knowledge, this is the first thorough study describing the ethnic prevalence of mutations and sequence variations in the glucokinase gene in NIDDM.

Adolescent↗
PubMed1993

Apolipoprotein E polymorphism is associated with plasma cholesterol response in a 7-day hospitalization study for metabolic and dietary control in NIDDM.

OBJECTIVE: To investigate the effects of apolipoprotein E phenotype, which is an important genetic factor determining plasma cholesterol level, on plasma lipoprotein metabolism during a 7-day diet therapy of diabetes. RESEARCH DESIGN AND METHODS: Diet therapy was performed in 242 subjects with NIDDM. Plasma lipid levels and apolipoprotein A-I, B, and E levels on hospital days 2 and 9 were compared in three phenotype groups, epsilon 2 (E2/2, and E2/3), epsilon 3 (E3/3), and epsilon 4 (E3/4 and E4/4). RESULTS: No differences were observed in fasting blood glucose level, body mass index, age, duration of NIDDM, or medication among the three phenotype groups. Before starting the treatment, total plasma cholesterol did not vary by apolipoprotein E phenotype, although the mean plasma low-density lipoprotein cholesterol level in epsilon 4 patients was higher than in either epsilon 3 or epsilon 2 patients (epsilon 4, 145 +/- 42; epsilon 3, 131 +/- 34; epsilon 2, 128 +/- 36 mg/dl; P < 0.05). Changes in fasting blood glucose/body mass index after the 7-day treatment were not different among the apolipoprotein E phenotype groups, whereas the decrease in plasma cholesterol level after the treatment was significantly greater in epsilon 2 patients than in either epsilon 3 or epsilon 4 patients (epsilon 2, 10.3 +/- 14.2; epsilon 3, 6.1 +/- 11.0; epsilon 4, 3.8 +/- 9.6%; P < 0.05). CONCLUSIONS: Total plasma cholesterol response to in-hospital diet therapy varies by apolipoprotein E phenotypes, with subjects with apolipoprotein E2 showing the greatest response, whereas those with apolipoprotein E4 show the least. We suggest that subjects with apolipoprotein E4 should be controlled more strictly than other subjects from a viewpoint of reducing plasma cholesterol levels.

Alleles↗
PubMed1993

Changes in subset specificity of anti-T cell autoantibodies in systemic lupus erythematosus.

Relative reactivity of anti-lymphocyte autoantibodies (ALA) from patients with systemic lupus erythematosus (SLE) against CD4+ and CD8+ T cells was studied using C-dependent microcytotoxicity assay. Of 46 SLE sera screened for anti-T cell autoantibodies, 27 sera (59%) showed significant cytotoxic reactivity. Of these, positive correlation between the titer of anti-T cell antibody and CD4/CD8 killing ratio (p < 0.01) was demonstrated. In time course study of individual patients, the CD4/CD8 killing ratio increased and decreased as the disease flared and subsided and was accompanied by parallel changes in the titer of anti-T cell antibody titer. Moreover, as sera were serially diluted, the CD4/CD8 killing ratio decreased in 5 out of 10 sera. These results suggest that discrepancy among reports concerning the subset specificity of anti-T cell antibodies may be due, in part, to differences in the titer of ALA in the sera studied and to the dilution of serum used.

Animals↗
PubMed1993

HLA B44-restricted cytotoxic T lymphocytes recognizing an epitope on hepatitis C virus nucleocapsid protein.

Cytotoxic T lymphocytes have been reported to be involved in the immune clearance of virus-infected cells and in the pathogenesis of viral infection. We studied the cytotoxic T lymphocyte response to the putative nucleocapsid protein of hepatitis C virus in patients with chronic hepatitis C. Cytotoxic T lymphocytes specific for hepatitis C virus nucleocapsid protein were generated from peripheral blood lymphocytes by means of repeated stimulation with a synthetic hepatitis C virus nucleocapsid protein peptide. The cytotoxic T lymphocytes were CD8 positive and recognized an epitope in hepatitis C virus nucleocapsid protein residues 81 to 100 in association with a human leukocyte antigen class I molecule, B44. The peptide-induced cytotoxic T lymphocytes recognized target cells synthesizing hepatitis C virus nucleocapsid protein endogenously, though less efficiently than peptide-pulsed target cells. The human leukocyte antigen B44-restricted cytotoxic T lymphocyte response was observed in three of five patients with chronic hepatitis C and a human leukocyte antigen B44 molecule but in neither of two hepatitis C virus-negative healthy individuals with human leukocyte antigen B44 molecules. The results demonstrate the presence of hepatitis C virus-specific cytotoxic T lymphocytes in the peripheral blood of patients with chronic hepatitis C and provide a strategy to study the role of cytotoxic T lymphocytes in the viral clearance and the pathogenesis of hepatitis C virus infection.

Antigens, Viral↗
PubMed1993

Detection of cardiac rejection in mice by radioimmune scintigraphy using 123iodine-labeled anti-ICAM-1 monoclonal antibody.

Intercellular adhesion molecule-1 (ICAM-1) is induced on allograft cells in association with acute rejection and plays important roles in the rejection process. Mice with abdominal heart transplants were studied to determine whether an increase in ICAM-1 expression in rejecting cardiac allografts could be detected by radioimmunoscintigraphy. Allografts from BALB/c donors were transplanted into C3H/He recipients (n = 7). Two of the allografted mice were treated with FK506 (2 mg/kg/day) and four isografted C3H/He mice served as controls. One to eight days after transplantation each mouse was injected intravenously with 50 microCi of 123I-labeled anti-ICAM-1 monoclonal antibody (YN1/1.7). After imaging the mice were killed for tissue counting and histopathology. Graft to native heart radiotracer uptake ratio in the mice with rejecting cardiac allograft (2.12 +/- 0.22, n = 5) was significantly greater than that in the mice with non-rejecting graft (1.23 +/- 0.14, n = 6, p < 0.001). In contrast to non-rejecting grafts, a rejecting allograft with lymphocyte infiltration but without myocyte necrosis and other allografts with relatively advanced rejection could be identified by the scintigraphy. We conclude that 123I-labeled anti-ICAM-1 antibody imaging is a noninvasive method for detecting cardiac allograft rejection.

Abdomen↗