Plasma concentrations of vascular endothelial growth factor are associated with peripheral oedema in patients treated with thiazolidinedione.
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Biomedical subjects
Publications and source records attributed to M Emoto.
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A higher body mass index (BMI) is a predictor of better survival in hemodialysis patients, although the relative importance of body fat and lean mass has not been examined in the dialysis population. We performed an observational cohort study in 808 patients with end-stage renal disease on maintenance hemodialysis. At baseline, fat mass was measured by dual-energy X-ray absorptiometry and expressed as fat mass index (FMI; kg/m2). Lean mass index (LMI) was defined as BMI minus FMI. During the mean follow-up period of 53 months, 147 deaths, including 62 cardiovascular (CV) and 85 non-CV fatal events, were recorded. In univariate analysis, LMI was not significantly associated with CV or non-CV death, whereas a higher FMI was predictive of lower risk for non-CV death. Analyses with multivariate Cox models, which took other confounding variables as covariates, indicated the independent associations between a higher LMI and a lower risk of CV death, as well as between a higher FMI and a lower risk of non-CV death. These results indicate that increased fat mass and lean mass were both conditions associated with better outcomes in the dialysis population.
The putative presence of a mutation in codon 12 of the K-ras gene was investigated in the endometrium of tamoxifen (TAM) and toremifene (TOR)-treated breast cancer patients. DNA was extracted from fresh cytologic samples of the endometrium in 86 TAM and 21 TOR-treated breast cancer patients. Mutations were detected by enriched PCR and an enzyme-linked mini-sequence assay (ELMA). K-ras mutation was found in 35 TAM-treated endometrial samples, and in only one TOR-treated endometrium (P<0.003). In 24 premenopausal patients, K-ras mutation was found in seven (43.8%) of 16 patients with less than 47 months of TAM treatment, while none was found in eight patients with more than 48 months of TAM treatment (P<0.03). In 62 postmenopausal-amenorrheic patients, K-ras mutation was found in three (15.8%) of 19 patients with less than 23 months of TAM treatment, while it was found in 16 (61.5%) of 26 patients with 24-47 months of TAM treatment and nine (52.9%) of 17 patients with more than 48 months of TAM treatment (P=0.002). The presence of K-ras mutation is significantly influenced by the duration of TAM treatment and menstrual status of the patients. TOR may have a lower potential genotoxicity than TAM.
Sawtooth oscillations have been observed in current-carrying helical plasmas by using electron-cyclotron-emission diagnostics in the Large Helical Device. The plasma current, which is driven by neutral beam injection, reduces the beta threshold of the sawtooth oscillation. When the central q value is increased due to the plasma current, the core region crashes, and, when it is decreased, the edge region crashes annularly. Observed rapid mixture of the plasma in the limited region suggests that these sawtooth crashes are reconnection phenomena. Unlike previous experiments, no precursor oscillation has been observed.
We assessed the presence of vascular endothelial growth factor (VEGF)-C, VEGF-D and their receptor VEGFR-3 by immunohistochemistry in 59 epithelial ovarian carcinomas, 11 borderline tumours and 20 benign cystadenomas. VEGF-C and VEGF-D were generally expressed in tumour cells and also in endothelia adjacent to tumour nests which showed a strong staining for them. VEGFR-3 was expressed in lymphatic and vascular endothelial cells adjacent to tumour nests. Immunoreactivity was significantly more frequent as lesions progressed from a benign tumour to advanced carcinoma. A strong correlation was found between VEGF-C and VEGF-D detected in carcinoma and VEGFR-3 detected in neighbouring endothelial cells. Increased expression of VEGF-C, VEGF-D and VEGFR-3 was significantly associated with lymph node metastasis and peritoneal metastasis outside the pelvis. There was a significant correlation between the high levels of VEGF-C and VEGF-D proteins, and poor survival. The presence of VEGF-D was an independent prognostic indicator by multivariate analysis. We conclude that VEGF-C, VEGF-D and VEGFR-3 play an important role in lymphatic spread and intraperitoneal tumour development in ovarian carcinoma. Since VEGF-D was found to be an independent predictor of poor outcome, its measurement, together with other prognostic markers may improve prospective identification of patients with a poor prognosis.
In the Large Helical Device plasma discharges, the size of an externally imposed island with mode number ( n/m = 1/1) decreases substantially when the plasma is collisionless ( nu(*)< approximately 1) and the beta is finite ( > approximately 0.1%) at the island location. For the collisional plasmas with finite beta, on the other hand, the size of the island increases. However, there is a threshold in terms of the vacuum island size below which the island enlargement is not seen.
The present study was undertaken to assess the effect of hyperthyroidism on stiffness in the common carotid artery (CCA) in patients with Graves' disease (GD) and elucidate the mechanism by which arterial stiffness is increased in hyperthyroidism. The arterial stiffness index beta (stiffness beta) was evaluated in the CCA using an ultrasonic phase-locked echo-tracking system. Stiffness beta was defined as the logarithm of the ratio of systolic to diastolic blood pressure divided by the fractional diameter increase during the cardiac cycle and thus established as a measure of arterial stiffness uninfluenced by the change in blood pressure. Seventy euthyroid GD patients were measured for CCA stiffness beta to determine its relationship to retinal blood flow and plasma levels of vascular injury markers. To investigate the effect of hyperthyroidism, 27 GD patients were measured for changes during antithyroid drug (ATD) therapy in stiffness beta and in hemodynamic parameters, retinal blood flow and plasma vascular injury markers. In euthyroid GD patients, stiffness beta in the CCA showed a significant and positive correlation with systolic blood pressure and pulse pressure, but not with peripheral blood flow in the central retinal artery. ATD therapy significantly reduced stiffness beta from 5.23 +/- 2.10 to 4.36 +/- 1.48. The fractional reduction of stiffness beta during ATD therapy correlated significantly with reductions in pulse pressure and retinal blood flow, but not with the reductions in systolic and mean blood pressure, or any of the plasma injury markers. In summary, the significant increase in stiffness beta in the hyperthyroid state may reflect the harmful effect of hyperthyroidism on the arterial wall, which may in turn result from increased stroke volume.
It was observed that the vacuum magnetic island produced by an external error magnetic field in the large helical device shrank in the presence of plasma. This was evidenced by the disappearance of flat regions in the electron temperature profile obtained by Thomson scattering. This island behavior depended on the magnetic configuration in which the plasmas were produced.
Recent large helical device experiments revealed that the transition from ion root to electron root occurred for the first time in neutral-beam-heated discharges, where no nonthermal electrons exist. The measured values of the radial electric field were found to be in qualitative agreement with those estimated by neoclassical theory. A clear reduction of ion thermal diffusivity was observed after the mode transition from ion root to electron root as predicted by neoclassical theory when the neoclassical ion loss is more dominant than the anomalous ion loss.
Insulin regulates glucose uptake in adipocytes and muscle by stimulating the movement of sequestered glucose transporter 4 (GLUT4) proteins from intracellular membranes to the cell surface. Here we report that optimal insulin-mediated GLUT4 translocation is dependent upon both microtubule and actin-based cytoskeletal structures in cultured adipocytes. Depolymerization of microtubules and F-actin in 3T3-L1 adipocytes causes the dispersion of perinuclear GLUT4-containing membranes and abolishes insulin action on GLUT4 movements to the plasma membrane. Furthermore, heterologous expression in 3T3-L1 adipocytes of the microtubule-binding protein hTau40, which impairs kinesin motors that move toward the plus ends of microtubules, markedly delayed the appearance of GLUT4 at the plasma membrane in response to insulin. The hTau40 protein had no detectable effect on microtubule structure or perinuclear GLUT4 localization under these conditions. These results are consistent with the hypothesis that both the actin and microtubule-based cytoskeleton, as well as a kinesin motor, direct the translocation of GLUT4 to the plasma membrane in response to insulin.
Cardiovascular risk is increased in patients with diabetic nephropathy. The aim of this study was to examine the relative impacts of albuminuria and renal failure, the two important features of diabetic nephropathy, on potentially atherogenic lipoprotein changes in this condition. The subjects were 160 non-diabetic healthy controls and a total of 200 type 2 diabetes patients with various degrees of nephropathy. The diabetic patients were divided into four groups by urinary albumin/creatinine ratio (U-ACR) and serum creatinine (S-Cr) levels: DM-1 (U-ACR< 30 mg/g, N=85), DM-2 (U-ACR=30-300 mg/g, N=48), DM-3 (U-ACR > 300 mg/g, N=29) and DM-4 (S-Cr>177 micromol/l or 2.0mg/dl, N=38). Lipids in very low (VLDL), intermediate (IDL), low (LDL), and high density (HDL) lipoproteins were measured following ultracentrifugation. VLDL-cholesterol (VLDL-C) was elevated (by 73-100%) in diabetic patients and it did not differ among the stages of nephropathy. IDL-C was higher as the nephropathy stage was advanced, and the elevation was significant in the DM-3 (by 75%) and DM-4 (by 131%) groups. LDL-C was not elevated in diabetic patients and was not different among the stages of nephropathy. Reduction of HDL-C was significant in DM-1, DM-2 and DM-3 (by 12-16%) and it was more exaggerated in DM-4 (by 35%). Multiple regression analyses indicated that elevated S-Cr, but not U-ACR, was an independent factor associated with raised IDL-C and lowered HDL-C in diabetic patients. These results indicate that diabetic patients with nephropathy show multiple lipoprotein changes, and that renal failure has greater impact than albuminuria on abnormalities in IDL and HDL. These lipoprotein alterations may contribute to an increased cardiovascular risk in diabetic nephropathy, especially in diabetic renal failure.
Stiffening and thickening of arterial wall are two important components of atherosclerosis. The purpose of this study was to evaluate the effects of femoral artery wall stiffness on clinical manifestation of peripheral vascular disease (PVD) in type 2 diabetes mellitus. The subjects were 315 patients with type 2 diabetes. Presence of intermittent claudication and/or leg pain at rest and reduced ankle-brachial blood pressure index (ABI<0.9) were used as a subjective and an objective index of PVD, respectively. Femoral artery intima-media thickness (FA-IMT) and stiffness parameter beta (FA-stiffness beta) were measured by ultrasound methods. Symptomatic patients (N=58) showed greater values for both FA-IMT and FA-stiffness beta than those without symptom (N=257). Similarly, patients with reduced ABI (N=56) had greater FA-IMT and FA-stiffness beta than those without (N=259). However, correlation between FA-IMT and FA-stiffness beta was not impressive, especially in the symptomatic patients. To evaluate the effect of FA-stiffness beta on PVD symptoms, the subjects were divided into three subgroups according to FA-IMT, and then FA-stiffness beta was compared between those with and without PVD symptoms in each subgroup. The symptomatic patients had greater FA-stiffness beta values than the asymptomatic subjects in all the three subgroups. Multiple logistic regression analysis indicated that the presence of PVD symptoms was associated more closely with increased FA-stiffness beta than with increased FA-IMT, whereas reduced ABI was associated more closely with FA-IMT than with FA-stiffness beta. These data suggest that stiffening of arterial wall has a significant impact on PVD manifestations, particularly on the leg symptoms, in patients with type 2 diabetes.
Diabetes mellitus is a strong risk factor for the progression of atherosclerosis. In patients with chronic renal failure on hemodialysis, advanced atherosclerosis is reported to be present. We examined how renal insufficiency affects intima-medial thickness (IMT) of the carotid and femoral arteries in patients with type 2 diabetes mellitus. IMT was measured by B-mode ultrasonography in 115 patients with type 2 diabetes mellitus (65 men, 50 women; 58 +/- 13 years old). The IMT of the carotid and the femoral artery of patients with creatinine clearance less than 80 mL/min (n = 55) were significantly greater than those of patients with creatinine clearance 80 mL/min or greater (n = 60; P < 0.01 and P < 0.05). Linear regression analyses showed that there was a significant negative correlation between creatinine clearance and IMT of the carotid artery (r = -0.330; P < 0.001) and femoral artery (r = -0.336; P < 0.001). Multiple regression analyses revealed that age and creatinine clearance significantly and independently affected the IMT of the carotid artery (R(2) = 0.176; P < 0.0001), and age, duration of diabetes, and smoking affected the IMT of the femoral artery (R(2) = 0.287; P < 0.0001). These findings show that decreased renal function accelerates atherosclerosis in patients with type 2 diabetes mellitus and that chronic renal failure is a significant, independent risk factor for carotid atherosclerosis in these patients.
Although it is generally assumed that T-cell receptor (TCR) gamma/delta cells participate in protection against intracellular microbial pathogens, their impact remains controversial. In our study, young (14-day-old) mice lacking TCRgamma/delta cells were far more susceptible to Listeria monocytogenes than wild-type (WT) mice of the same age. The number of interferon gamma (IFN-gamma) producers responsible for antilisterial resistance was significantly higher among natural killer (NK)1(+) TCRgamma/delta cells than among NK1(-) TCRgamma/delta cells. Endogenous IFN-gamma neutralization increased susceptibility of young WT mice to L. monocytogenes infection. Liver was a major residence of peripheral NK1(+) TCRgamma/delta cells, whereas NK1(-) TCR gamma/delta cells were broadly distributed in various lymphoid organs. Numbers of both NK1(+) and NK1(-) TCRgamma/delta cells increased in the liver of WT mice prior to TCRalpha/beta cells and represented a substantial population in early life (14 days after birth). Virtually all NK1(+) TCRgamma/delta cells expressed activation markers, whereas substantial numbers of NK1(-) TCRgamma/delta cells showed a naive phenotype. We conclude that TCRgamma/delta cells play a critical role in protection against L. monocytogenes in the early life of mice, probably because their TCRalpha/beta cell compartment is not fully competent. For this antibacterial function, we assign NK1(+) TCRgamma/delta cells a more important role than their NK1(-) cognates.
Paraoxonase is a high-density lipoprotein (HDL)-bound esterase that hydrolyzes various organophosphorus compounds and protects low-density lipoprotein (LDL) against accumulation of lipid peroxides. Paraoxonase activity is strongly affected by the polymorphism of the paraoxonase gene (PON1) at position 192. In addition, the enzyme activity shows a great variation within each genotype, although the underlying mechanism is unknown. Because paraoxonase activity is decreased in subjects with type 2 diabetes mellitus who have insulin resistance, we investigated the association between paraoxonase activity and insulin resistance in a nondiabetic population. The subjects were 237 healthy Japanese adults with fasting plasma glucose less than 7.0 mmol/L. Paraoxonase activity was measured using paraoxon as a routine substrate. Insulin resistance was assessed by homeostasis model assessment index (HOMA index). Paraoxonase activity was affected by HDL level. To reduce the effect of HDL on paraoxonase, paraoxonase activity/HDL ratio was used. When the subjects were divided into tertiles by HOMA index, the subjects with higher HOMA values had higher paraoxonase/HDL ratios, although the 3 groups were comparable in age, gender and the PON1 genotype distribution. Paraoxonase/HDL ratio showed significant positive correlations not only with HOMA index, but also with body mass index, waist-to-hip ratio (WHR), whereas it correlated inversely with age at borderline significance. Multiple regression analysis indicated that the association between HOMA index and paraoxonase/HDL ratio was significant and independent of PON1 genotype, age, and adipocity. The positive association between HOMA index and HDL-corrected enzyme activity was again significant when the enzyme activity was measured with diazoxon as an alternative substrate. These results suggest that insulin resistance or hyperinsulinemia is a factor contributing to the intragenotype variability of paraoxonase activity in a population without overt hyperglycemia.
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OBJECTIVE: Graves' ophthalmopathy (GO), resulting from the inflammation of retro-orbital tissue, is one of the major complications of Graves' disease (GD). We investigated the clinical usefulness of the measurement of retinal blood flow (RBF) in the evaluation of GO and its activity. MEASUREMENT: RBF was quantitated by pulsed Doppler mode at just below the branch of central retinal artery, from which the resistance index (RI) was calculated. PATIENTS: Forty-seven euthyroid GD patients and 70 gender- and age-matched normal controls were measured for RI to investigate the effect of GO on RBF. To investigate the effect of hyperthyroidism, 20 GD patients were measured for RI changes during antithyroid drug (ATD) therapy. Furthermore, 17 GD patients with clinically overt GO were measured for RI changes during treatment with glucocorticoid plus retro-orbital radiation. RESULTS: RI and exophthalmos showed a significant positive correlation in 47 treated euthyroid GD patients without clinically overt GO (r=0.307, P<0.05), but not in 70 age- and sex-matched normal subjects (r=0.185, P=0.161). Furthermore, RI, but not exophthalmos, significantly correlated with serum TSH receptor antibodies, an indicator for the disease activity of GO. ATD therapy significantly reduced RI in GD patients from 0.719+/-0.041 in the hyperthyroid state to 0.661+/-0.051 in the euthyroid state, but not to the levels observed in normal subjects having the similar exophthalmos (0.640+/-0.049). The fractional reduction of RI during ATD therapy significantly correlated with those of pulse pressure and ultrasonographic distensibility in carotid artery, but not with those of serum vascular injury markers. In 17 GD patients with clinically overt GO, all four patients having adipose tissue enlargement but not extraocular muscle hypertrophy (inactive GO) showed RI within the mean +/- 1 s.d. for treated GD patients without GO. In the other 13 GD patients having extraocular muscle hypertrophy (active GO), four and eight patients showed RI outside mean +/- 2 s.d. and mean +/- 1 s.d. respectively. Treatment with glucocorticoid plus radiation moved RI in 8 out of 10 patients toward the mean values of GD patients without GO, in spite of little improvement of exophthalmos. CONCLUSIONS: It was suggested that GD patients showed altered retinal hemodynamics, possibly resulting either from the cardiovascular effect of hyperthyroidism or from retro-orbital inflammation, particularly in extraocular muscle.
Troglitazone is one of the thiazolidinediones, a new class of oral antidiabetic compounds that are ligands of peroxisome proliferator-activated receptor-gamma. This study on vascular endothelial growth factor (VEGF), also known as vascular permeability factor, was prompted by our clinical observation that the characteristics of troglitazone-induced edema were very similar to those caused by vascular hyperpermeability. When Japanese diabetic patients were screened for plasma VEGF, we found levels to be significantly (P < 0.001) increased in troglitazone-treated subjects (120.1 +/- 135.0 pg/ml, n = 30) compared with those treated with diet alone (29.2 +/- 36.1 pg/ml, n = 10), sulfonylurea (25.8 +/- 22.2 pg/ml, n = 10), or insulin (24.6 +/- 19.0 pg/ml, n = 10). Involvement of troglitazone in increased VEGF levels was further supported by the plasma VEGF levels in five patients before treatment (20.2 +/- 7.0 pg/ml), after 3 months of troglitazone treatment (83.6 +/- 65.9 pg/ml), and 3 months after discontinuation (28.0 +/- 11.6 pg/ml). We further demonstrated that troglitazone, as well as rosiglitazone, at the plasma concentrations observed in patients, increased VEGF mRNA levels in 3T3-L1 adipocytes. VEGF is an angiogenic and mitogenic factor and is currently considered the most likely cause of neovascularization and hyperpermeability in diabetic proliferative retinopathy. Although increased VEGF may be beneficial for subjects with macroangiopathy and troglitazone is currently not available for clinical use, vascular complications, especially diabetic retinopathy, must be followed with great caution in subjects treated with thiazolidinediones.