Epitaxial growth of SiGe films by annealing Al-Ge alloyed pastes on Si substrate.

A simple, low-cost, and non-vacuum epitaxial growth method to realize large-area semiconductors on crystalline silicon will become the game-changer for various applications. For example, we can expect the disruptive effect on the cost of large-scale III-V multi-junction solar cells if we could replace the high-cost germanium substrate with silicon-germanium (SiGe) on Si. For SiGe epitaxial growth, we attempted to develop a process using original Al-Ge pastes for screen printing and subsequent annealing. We compare two pastes including Al-Ge alloyed pastes with compositional uniformity in each particle and Al-Ge mixed pastes. We revealed that Al-Ge alloyed paste could form flatter SiGe film with much less residual pastes, supported by in-situ observations. The uniform and sufficient dissolution of the alloyed paste is responsible for these and led to higher average Ge-composition by annealing at 500 °C. The composition in SiGe was vertically graded up to ~ 90% at the topmost surface. These results show that printing and firing of Al-Ge alloyed paste on Si is the desirable, simple, and high-speed process for epitaxial growth of SiGe, which could be potentially used as the lattice-matched virtual substrate with III-V semiconductors.

Synthesis of omega-hydroxy carboxylic acids and alpha,omega-dimethyl ketones using alpha,omega-diols as alkylating agents.

Synthesis of omega-hydroxy carboxylic acids and alpha,omega-dimethyl diketones was successfully achieved by using alpha,omega-diols as alkylating agents under the influence of an iridium catalyst. For example, the alkylation of butyl cyanoacetate with 1,13-tridecanediol in the presence of [IrCl(cod)](2) or [IrCl(coe)(2)](2) gave rise to butyl 2-cyano-15-hydroxypentadecanoate in good yield which is easily converted to cyclopentadecanolide (CPDL). In addition, the alkylation of acetone with 1,10-decanediol in the presence of [IrCl(cod)](2) and KOH resulted in an important muscone precursor, 2,15-hexadecanedione (HDDO), in good yield.

Anxiety-induced plasma norepinephrine augmentation increases reactive oxygen species formation by monocytes in essential hypertension.

BACKGROUND: An association between anxiety and depression and increased blood pressure (BP) and cardiovascular disease risk has not been firmly established. We examined the hypothesis that anxiety and depression lead to increased plasma catecholamines and to production of reactive oxygen species (ROS) by mononuclear cells (MNC) in hypertensive individuals. We also studied the role of BP in this effect. METHODS: In Protocol 1, a cross-sectional study was performed in 146 hypertensive patients to evaluate whether anxiety and depression affect BP and ROS formation by MNC through increasing plasma catecholamines. In Protocol 2, a 6-month randomized controlled trial using a subtherapeutic dose of the alpha(1)-adrenergic receptor antagonist doxazosin (1 mg/day) versus placebo in 86 patients with essential hypertension was performed to determine whether the increase in ROS formation by MNC was independent of BP. RESULTS: In Protocol 1, a significant relationship was observed between the following: trait anxiety and plasma norepinephrine (r = 0.32, P < .01); plasma norepinephrine and ROS formation by MNC (r = 0.36, P < .01); and plasma norepinephrine and systolic, diastolic, and mean BP (r = 0.17, P = .04; r = 0.26, P = .02; r = 0.23, P < .01, respectively). In Protocol 2, subtherapeutic doxazosin treatment (1 mg/day) had no significant effect on BP. However doxazosin significantly decreased ROS formation by MNC compared with placebo (P < .01). CONCLUSION: Trait anxiety may increase plasma norepinephrine and increase ROS formation by MNC independent of BP in hypertensive patients.

Benidipine, a long-acting calcium channel blocker, inhibits oxidative stress in polymorphonuclear cells in patients with essential hypertension.

To study the relationship between blood pressure and oxidative stress in leukocytes, the effect of benidipine on these variables was compared with that of a placebo. Hypertensive patients were randomly assigned benidipine 4 mg (n=40) or placebo (n=40), and treated for 6 months. Oxidative stress in polymorphonuclear cells (PMNs) was measured by gated flow cytometry. There was a significant relationship between systolic or diastolic arterial pressure and reactive oxygen species (ROS) formation by PMNs in the benidipine group (r=0.61, p<0.01) and in the placebo group (r=0.58, p<0.01). After administration of 4 mg benidipine, ROS formation by PMNs fell by 32 arbitrary units (n=40, p<0.01). After administration of placebo, ROS formation by PMNs decreased by 0.6 arbitrary units (n=40, p=0.31) (p<0.01 for differing treatment effects). There was a significant relationship between the decrease in systolic arterial pressure and the decrease in ROS formation by PMNs in the benidipine group (r=0.52, p<0.01), but not in the placebo group (r=-0.08, p=0.61). There was also a significant relationship between the decrease in diastolic arterial pressure and decrease in ROS formation by PMNs in the benidipine group (r=0.65, p<0.01) but not in the placebo group (r=-0.09, p=0.59). In hypertensive patients, we observed a significant relationship between systolic or diastolic blood pressure and ROS formation by PMNs, and found that benidipine decreased oxidative stress in PMNs of hypertensive patients, at least in part by decreasing blood pressure.

Enhanced oxidative stress in neutrophils from hyperlipidemic guinea pig.

Inhibitors of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase are antilipidemic agents (statins) widely used for the prevention of cardiovascular diseases. Recent studies have suggested that the overall benefits of statin therapy cannot be accounted for solely by its antilipidemic effect. To obtain further insight into the mechanism of action of statins, we studied the effect of pitavastatin on the generation of reactive oxygen species (ROS) by peritoneal polymorphonuclear leukocytes (PMN) obtained from control and hyperlipidemic guinea pigs. Flow cytometric analysis revealed that the amount of ROS generated by PMN from the hyperlipidemic animals that had been administered a laurate-containing diet (LD) for 4 weeks was larger than that from the normal diet (ND) group (837% increase, ND; 82.17 arbitrary units, LD; 688.10 arbitrary units, P < 0.01, n = 6). Administration of pitavastatin to the LD group significantly decreased plasma levels of total cholesterol (TC) and low-density lipoprotein (LDL) with a reduction in ROS generation by PMN (19% decrease, LD control; 688.10 arbitrary units, LD + pitavastatin; 556.87 arbitrary units, P < 0.01, n = 6). Western blotting analysis revealed that the expression of protein kinase C alpha (PKC alpha) and betaI was higher in PMN from the LD group than in PMN from the ND group (PKC alpha; 74% increase, PKC betaI; 339% increase, P < 0.05, n = 4, respectively). Furthermore, expression of NADPH oxidase gp91phox in PMN from the LD group was higher than that in PMN from the ND group (18% increase, P < 0.05, n = 4). By administration of pitavastatin to the LD group, the expression of PKC alpha, betaI and gp91phox was suppressed compared with the control LD group (PKC alpha; 41% decrease, PKC beta; 28% decrease, gp91phox; 56% decrease, P < 0.05, n = 4, respectively). These results indicate that PMN from hyperlipidemic animals is associated with an accelerated respiratory burst of ROS by increasing the expression of PKC alpha, betaI and gp91phox, and pitavastatin inhibits this by suppressing the expression of those proteins.

Oxidative stress by peripheral blood mononuclear cells is increased in hypertensives with an extreme-dipper pattern and/or morning surge in blood pressure.

Because oxidative stress and inflammation are known to play important roles in the pathogenesis of cardiovascular events that occur most frequently in the morning, we studied the association between reactive oxygen species (ROS) formation by polymorphonuclear leukocytes (PMNs) or mononuclear cells (MNCs) and morning blood pressure (BP) rhythm. A total of 31 hypertensives in whom ambulatory BP monitoring was performed participated in this study. They were first divided into three groups according to their nocturnal BP rhythm (non-dippers, dippers and extreme dippers), and then into two groups according to their morning BP change (surge-type and sustained-type). ROS formation by PMNs and MNCs was measured by gated flow cytometry. C-reactive protein and traditional risk factors such as age, gender, body mass index, hemoglobin A1c, and total cholesterol were also measured. ROS formation by MNCs was significantly increased in extreme dippers (vs. dippers, p<0.05, n=11) and in morning BP surge-type hypertensives (vs. sustained-type, p<0.05, n=13). In patients who were both extreme dippers and morning BP surge-types, ROS formation by MNCs was significantly higher than that in other groups. These results suggest that both extreme dippers and morning BP surge-type hypertensives may suffer increased ROS formation by MNCs, and that increased ROS formation by MNCs may underlie morning strokes.

Pharmacological and clinical studies with temocapril, an angiotensin converting enzyme inhibitor that is excreted in the bile.

Temocapril is an angiotensin converting enzyme inhibitor (ACEI), a prodrug with a thiazepine ring. Its active form, temocaprilat, is slightly more potent than enalaprilat in inhibiting ACE isolated from rabbit lung. The inhibitory potency of temocaprilat on isolated rat aorta is 3 times that of enalaprilat. Temocapril is excreted in the bile and urine and can be used in patients with renal insufficiency. It reduces blood pressure without causing any significant change in heart rate or cardiac output. Temocapril has been reported to improve endothelial dysfunction in vitro by suppressing increased oxidative stress. In vivo it improves reactive hyperemia in patients with essential hypertension. It has been reported to prevent coronary vascular remodeling in vivo by suppressing local ACE and increased oxidative stress. In humans temocapril has been found to improve insulin resistance partly by increasing adiponectin levels. Cardiac remodeling was improved by temocapril not only in experiment animals but also in humans. It improves renal function and decreases urinary albumin excretion in diabetics as well as in hypertensive patients. Temocapril is currently marketed only in Japan. Considering its beneficial effects and unique pharmacokinetics, temocapril, is likely to be introduced in other countries as well.

Comparative effects of valsartan versus amlodipine on left ventricular mass and reactive oxygen species formation by monocytes in hypertensive patients with left ventricular hypertrophy.

OBJECTIVES: To compare the effects of the angiotensin receptor blocker (ARB) valsartan versus the calcium channel blocker amlodipine, reactive oxygen species (ROS) formation by monocytes, C-reactive protein (CRP), and left ventricular (LV) mass were studied in 104 hypertensive patients with left ventricular hypertrophy (LVH). BACKGROUND: There is evidence that ARBs have blood pressure (BP)-independent effects on LV mass. Whether regression of LV mass by ARBs is correlated to ROS formation by monocytes and CRP is not fully understood yet. METHODS: A cross-sectional and prospective study was performed. Participants were randomly assigned to either the 80-mg valsartan (n = 52) or 5-mg amlodipine (n = 52) group and were treated for eight months. The left ventricular mass index (LVMI) was calculated from two-dimensional M-mode echocardiography. Formation of ROS by monocytes was measured by gated flow cytometry. In addition, CRP, plasma renin activity, plasma aldosterone, and traditional risk factors were assessed. RESULTS: Multiple regression analysis showed a significant correlation between LVMI and ROS formation by monocytes and between LVMI and CRP. Treatment reduced BP to a similar extent in both groups. Valsartan significantly reduced LVMI after eight months, but amlodipine had less effect (16% vs. 1.2%, n = 50, p < 0.01). Formation of ROS by monocytes was reduced to a greater extent with valsartan than with amlodipine (28% vs. 2%, n = 50, p < 0.01). Valsartan but not amlodipine reduced CRP levels. A significant correlation between changes in ROS formation by monocytes and LVMI or between CRP and LVMI was observed. CONCLUSIONS: The ARB valsartan has BP-independent effects on LVH, ROS formation by monocytes, and CRP in hypertensive patients with LVH.

Effects of carvedilol on oxidative stress in polymorphonuclear and mononuclear cells in patients with essential hypertension.

PURPOSE: To compare the effects of carvedilol and propranolol on oxidative stress in leukocytes and C-reactive protein levels in patients with hypertension. METHODS: Sixty hypertensive patients were randomly assigned to carvedilol (20 mg; n = 30) or propranolol (60 mg; n = 30) for 6 months. Thirty normotensive subjects who were given placebo served as controls. Oxidative stress in polymorphonuclear cells and mononuclear cells were measured by gated flow cytometry. C-reactive protein levels were measured by immunonephelometric assay. RESULTS: Oxidative stress in polymorphonuclear cells and mononuclear cells was increased significantly in hypertensive patients compared with in normotensive controls. After 6 months of treatment, carvedilol decreased oxidative stress significantly in polymorphonuclear cells by a mean of 45 arbitrary units (95% confidence interval [CI]: 32 to 59 arbitrary units; P <0.001) and propranolol decreased oxidative stress significantly by 20 arbitrary units (95% CI: 7 to 33 arbitrary units; P <0.003; P = 0.001 for difference between treatments). Carvedilol also decreased oxidative stress significantly in mononuclear cells by 23 arbitrary units (95% CI: 15 to 31 arbitrary units; P <0.001), whereas propranolol decreased oxidative stress by 2 arbitrary units (95% CI: 7 to 12 arbitrary units; P = 0.62; P = 0.002 for difference between treatments). Carvedilol decreased C-reactive protein levels significantly by a median of 0.073 mg/dL (interquartile range, 0.034 to 0.112 mg/dL; P <0.001), whereas propranolol decreased levels by 0.012 mg/dL (interquartile range, 0.009 to 0.032 mg/dL; P = 0.26; P = 0.003 for difference between treatments). CONCLUSION: These findings suggest that carvedilol inhibits oxidative stress in polymorphonuclear and mononuclear cells, as well as lowers C-reactive protein levels, to a greater extent than does propranolol in hypertensive patients.

Dopamine as a novel anti-migration factor of vascular smooth muscle cells through D1A and D1B receptors.

To elucidate the roles of rat vascular dopamine D1A and D1B receptors in vascular smooth muscle cell migration, the effect of antisense oligonucleotides to D1A receptors (+1 to +21 of rat D1A receptors) and to D1B receptors (-12 to +6 of rat D1B receptors) on dopamine-mediated suppression of platelet-derived growth factor BB-mediated vascular smooth muscle cell migration, evaluated by the Boyden's chamber method, was studied. Increased vascular smooth muscle cell migration by platelet-derived growth factor BB (5 ng/ml) was suppressed significantly by co-incubation with dopamine (0.025-10 micromol/l) (by 15-59%). This suppression by 10 micromol/l dopamine was reversed by D1A antisense oligonucleotides (46%) and D1B antisense oligonucleotides (51%), but by neither the sense nor the random sense oligodeoxynucleotides to these receptors. The suppression by antisense oligodeoxynucleotides (21-51%) is dose dependent (1-10 micromol/l) and time dependent (0-4 h). Dopamine (10 micromol/l)-induced cyclic AMP formation is also suppressed by D1A antisense oligonucleotides (50%) and D1B antisense oligonucleotides (58%), but by neither the sense nor the random sense oligodeoxynucleotides to these receptors. The platelet-derived growth factor BB (5 ng/ml)-mediated activation of phospholipase D and protein kinase C activities were significantly suppressed by co-incubation with 10 micromol/l dopamine, which was reversed by D1A antisense oligonucleotides (45%) and D1B antisense oligonucleotides (50%) but by neither the sense nor the random sense oligodeoxynucleotides to these receptors. These results suggest that vascular D1A and D1B receptors inhibit migration of vascular smooth muscle cells, possibly through cyclic AMP activation and the suppression of phospholipase D and protein kinase C activities.

Activation of protein kinase C and nicotinamide adenine dinucleotide phosphate oxidase in leukocytes of spontaneously hypertensive rats.

The involvement of oxidative stress in polymorphonuclear leukocytes (PMN) in the pathogenesis of hypertension remains to be elucidated. We analyzed the generation of reactive oxygen species (ROS) by the circulating and peritoneally infiltrating PMN from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Flow cytometric analysis revealed that ROS generation by PMN from SHR was higher than that from WKY before (at 6 weeks of age) and after (at 16 weeks of age) the onset of hypertension. In vivo, ROS generation by PMN from SHR, but not that by PMN from WKY, was significantly suppressed by 10-week treatment with 50 mg/kg/day carvedilol, and this treatment did not affect blood pressure. Western blotting analysis revealed that protein kinase C alpha (PKCalpha), but not PKCbetaI or betaII, was activated more strongly in PMN from SHR than in PMN from WKY. Furthermore, expression of p47phox of nicotinamide adenine dinucleotide phosphate oxidase, but not of p67phox, in PMN from SHR was higher than that in PMN from WKY. These results suggest that ROS generation by PMN is principally enhanced in SHR through activation of PKCalpha and p47phox.

Converting enzyme inhibitor temocaprilat prevents high glucose-mediated suppression of human aortic endothelial cell proliferation.

We examined the involvement of the oxidative stress in high glucose-induced suppression of human aortic endothelial cell proliferation. Chronic glucose treatment for 72 h concentration-dependently (5.6-22.2 mol/l) inhibited human coronary endothelial cell proliferation. Temocaprilat, an angiotensin-converting enzyme inhibitor, at 10 nmol/l to 1 micromol/l inhibited high glucose (22.2 mmol/l)-mediated suppression of human aortic endothelial cell proliferation. Temocaprilat at 1 micromol/l inhibited high glucose-induced membrane-bound protein kinase C activity in human aortic endothelial cells. The protein kinase C inhibitors calphostin C 100 nmol/l or chelerythrine 1 micromol/l inhibited high glucose-mediated suppression of human aortic endothelial cell proliferation. Chronic high glucose treatment for 72 h increased intracellular oxidative stress, directly measured by flow cytometry using carboxydichlorofluorescein diacetate bis-acetoxymethyl ester, and this increase was significantly suppressed by temocaprilat 10 nmol/l to 1 micromol/l. Bradykinin B2 receptor antagonist icatibant 100 nmol/l significantly reduced the action of temocaprilat; whereas bradykinin B1 receptor antagonist des-Arg9-Leu8-bradykinin 100 nmol/l had no effect. These findings suggest that high glucose inhibits human aortic endothelial cell proliferation and that the angiotensin-converting enzyme inhibitor temocaprilat inhibits high glucose-mediated suppression of human aortic endothelial cell proliferation, possibly through suppression of protein kinase C, bradykinin B2 receptors and oxidative stress.

Carvedilol inhibits pressure-induced increase in oxidative stress in coronary smooth muscle cells.

The cellular mechanisms by which hypertension enhances atherosclerosis are still not known in detail. Recently, evidence has been obtained that oxidative stress plays a role in the pathogenesis of pressure-induced atherosclerosis. We examined the effects of pressure on oxidative stress in cultured human coronary smooth muscle cells (SMCs). Application of increased pressure (+100 mmHg) with He gas for 48 h increased oxidative stress of measured by flow cytometry by 71% and F2-isopretane by 77%. Increased pressure also increased the activities of phospholipase D (PLD), and particulate protein kinase C (PKC). The PLD inhibitor suramin 100 micromol/l, 1-butanol 40 mmol/l, and the PKC inhibitors chelerythrine 1 micromol/l and calphostin C 100 nmol/l and completely blocked the increase in oxidative stress induced by pressure. Carvedilol 1 micromol/l but not propranolol 1 micromol/l blocked pressure-induced increases in oxidative stress in cultured SMCs. These findings suggest that pressure increases oxidative stress and that carvedilol significantly inhibits pressure-induced increase in oxidative stress in cultured human coronary smooth muscle cells.

Pressure promotes angiotensin II--mediated migration of human coronary smooth muscle cells through increase in oxidative stress.

Angiotensin II--mediated oxidative stress may play a role in the pathogenesis of coronary atherosclerosis. We examined the effects of pressure on the angiotensin II--mediated increase in oxidative stress and migration of cultured human coronary smooth muscle cells (SMCs). Increased pressure (100 mm Hg) by helium gas for 48 hours increased angiotensin II--mediated oxidative stress as evaluated by flow cytometry and SMC migration (from 15.9 +/- 2.2 to 32.0 +/- 2.4 cells per 4 high-power fields, P<0.05; n=8). The pressure-induced increases in oxidative stress observed appear to involve phospholipase D (PLD) and protein kinase C (PKC), inasmuch as the indirect PLD inhibitor suramin, at 100 micromol/L, and the PKC inhibitor chelerythrine, at 1 micromol/L, completely blocked the increase in angiotensin II--mediated oxidative stress induced by pressure. Pressure-induced increase in angiotensin II--mediated oxidative stress was inhibited by diphenylene iodonium chloride, an NADPH oxidase inhibitor, by 79% (P<0.05, n=8). Losartan (1 micromol/L), its active metabolite E3174 (1 micromol/L), and the antioxidant N-acetylcysteine (100 mmol/L) but not PD123319 (1 micromol/L) also blocked pressure-induced increases in angiotensin II--mediated oxidative stress and SMC migration (P<0.05, n=8). These findings suggest a novel cellular mechanism whereby pressure regulates the angiotensin II--mediated migration of SMCs, possibly via angiotensin II type 1 receptors, and which involves PLD-mediated, PKC-mediated, and NADPH oxidase--mediated increases in oxidative stress.

Oxidative stress in leukocytes is a possible link between blood pressure, blood glucose, and C-reacting protein.

Because oxidative stress and inflammation are believed to play roles in the pathogenesis of cardiovascular diseases, oxidative stress in polymorphonuclear leukocytes (PMNs) and mononuclear cells (MNCs) has been measured. A total of 529 subjects participated this study. Intracellular oxidative stress in PMNs and MNCs was measured by gated flow cytometry using carboxyfluorescin diacetate bis-acetoxymethyl ester. C-reacting protein (CRP), insulin action (homeostasis model assessment), and traditional risk factors such as age, gender, body mass index, triglycerides, LDL cholesterol, HDL cholesterol, hemoglobin A(1c), and mean blood pressure were also measured. Multiple regression analysis revealed a significant correlation between mean blood pressure and PMN oxidative stress (r=0.104, P=0.018). It also demonstrated a significant correlation between hemoglobin A(1c) and PMN oxidative stress (r=0.112, P=0.021). A significant correlation was also found between CRP and MNC oxidative stress (r=0.116, P=0.008) by multiple regression analysis. In patients with both hypertension and diabetes, both PMN and MNC oxidative stress was increased (n=21, P=0.022 and P=0.006). These results suggest that both hypertension and diabetes lead to increased oxidative stress of PMNs and MNCs, and that CRP is related to MNC oxidative stress.