Effect Of Pressure Reduction Research Articles

Nonlinear Analysis of Pressurized Piping Elbows Subjected to Out-of-Plane Bending

The behavior of piping elbows under bending and internal pressure is more complicated than expected. The main problem is that the coupling of bending and internal pressure is nonlinear; the resulting stress and displacement cannot be added according to the principle of superposition. In addition, internal pressure tends to act against the effect caused by the bending moment. If bending moment ovalise the elbow cross-section, with internal pressure acting against this deformation, then the ovalised cross section deform back to the original circular shape. It is then introduced the term “pressure reduction effect”, or in some literature, “pressure stiffening effect”. Current design piping code treats the pressure reduction effect equally for in-plane (closing and opening) moment and outof- plane moment. The aim of this paper is to present results of a detailed finite element analysis on the non-linear behavior of piping elbows of various geometric configurations subject to out-of-plane bending and internal pressure. Specifically the standard Rodabaugh & George nonlinear pressure reduction equations for in-plane closing moment are checked in a systematic study for out-of-plane moment against nonlinear finite element analysis. The results show that the pressure stiffening effects are markedly different for in-plane and out-of-plane bending.

Effect of Nocturnal Blood Pressure Reduction on Circadian Fluctuation of Mean Ocular Perfusion Pressure: A Risk Factor for Normal Tension Glaucoma

To study blood pressure (BP), intraocular pressure (IOP), and mean ocular perfusion pressure (MOPP) in patients with untreated normal tension glaucoma (NTG), and to investigate the relationship between circadian MOPP fluctuation and visual field status at initial presentation. IOP and BP were evaluated in hospital over 24 hours in 132 patients with NTG, with measurements taken every 2 hours between 12 PM and 10 AM the following day, except for the period between 12 and 6 AM, during which measurements were taken every 3 hours. MOPP was calculated from the 24-hour IOP and BP data. Patients were classified into three groups-nondippers, dippers, and overdippers-corresponding to the degree of reduction in their nocturnal mean arterial pressure (MAP) compared with their diurnal MAP. IOP and systemic and ocular hemodynamic parameters were compared among the groups. The correlations between circadian MOPP fluctuation and visual field scores (mean deviation [MD] and corrected pattern standard deviation [CPSD]) at initial presentation were analyzed. Forty-one (31.1%) of the patients with NTGs were classified into the nondipper group, 36 (27.2%) into the dipper group, and 55 (41.7%) into the overdipper group. Marked circadian MOPP fluctuation was noted in the overdipper group (P < 0.05). Circadian MOPP fluctuation showed positive associations with visual field indices at initial diagnosis of NTG (P < 0.05, R2 = 0.056 with MD, R2 = 0.038 with CPSD). Marked circadian MOPP fluctuation was associated with nocturnal BP reduction. Circadian MOPP fluctuation may be a risk factor for the development of NTG.

Volume Control Associated with Better Cardiac Function in Long-Term Peritoneal Dialysis Patients

This study was undertaken to investigate the effect of long-term blood pressure (BP) reduction, achieved with salt restriction and strict volume control, on frequency and regression of left ventricular hypertrophy (LVH) in long-term peritoneal dialysis (PD) patients. 56 patients who had been treated for more than 2 years under our care were enrolled. After echocardiographic (Echo) evaluation, 46 patients were included in the follow-up study. In our unit, we aim to keep patients' BP below 130/85 mmHg and cardiothoracic index below 0.50. To reach these targets, moderate salt restriction is advised, and if necessary, hypertonic PD solutions are used. Echo was performed at the beginning of the study (after a mean period of 36 months on PD) and at the end of the prospective follow-up period (24 months later). At the time of the first Echo, LVH was detected in only 8 (21%) patients. Residual urine volume was significantly decreased compared to data taken when they first started PD (658 +/- 795 vs 236 +/- 307 mL/day). Mean left ventricular mass index (LVMI) was 107 +/- 26.5 g/m2. LVMI was significantly decreased at the end of the follow-up in patients who had LVH at baseline. No LVH developed in patients who had normal LVMI at baseline. Our results indicate that control of hypertension is possible when extracellular fluid volume is kept under control using hypertonic PD solutions in case of recruitment in addition to salt restriction in long-term PD patients. Sustained normovolemia is associated with low incidence and regression of LVH.

Differential Expression of Components of the Cardiomyocyte Adrenomedullin/Intermedin Receptor System following Blood Pressure Reduction in Nitric Oxide-Deficient Hypertension

Adrenomedullin (AM) and intermedin (IMD; adrenomedulln-2) are vasodilator peptides related to calcitonin gene-related peptide (CGRP). The actions of these peptides are mediated by the calcitonin receptor-like receptor (CLR) in association with one of three receptor activity-modifying proteins. CGRP is selective for CLR/receptor activity modifying protein (RAMP)1, AM for CLR/RAMP2 and -3, and IMD acts at both CGRP and AM receptors. In a model of pressure overload induced by inhibition of nitric-oxide synthase, up-regulation of AM was observed previously in cardiomyocytes demonstrating a hypertrophic phenotype. The current objective was to examine the effects of blood pressure reduction on cardiomyocyte expression of AM and IMD and their receptor components. Nomega-nitro-L-arginine methyl ester (L-NAME) (35 mg/kg/day) was administered to rats for 8 weeks, with or without concurrent administration of hydralazine (50 mg/kg/day) and hydrochlorothiazide (7.5 mg/kg/day). In left ventricular cardiomyocytes from L-NAME-treated rats, increases (-fold) in mRNA expression were 1.6 (preproAM), 8.4 (preproIMD), 3.4 (CLR), 4.1 (RAMP1), 2.8 (RAMP2), and 4.4 (RAMP3). Hydralazine/hydrochlorothiazide normalized systolic blood pressure (BP) and abolished mRNA up-regulation of hypertrophic markers sk-alpha-actin and BNP and of preproAM, CLR, RAMP2, and RAMP3 but did not normalize cardiomyocyte width nor preproIMD or RAMP1 mRNA expression. The robust increase in IMD expression indicates an important role for this peptide in the cardiac pathology of this model but, unlike AM, IMD is not associated with pressure overload upon the myocardium. The concordance of IMD and RAMP1 up-regulation indicates a CGRP-type receptor action; considering also a lack of response to BP reduction, IMD may, like CGRP, have an anti-ischemic function.

Report from the Cardiovascular and Renal Drugs Advisory Committee: US Food and Drug Administration; June 15-16, 2005; Gaithersburg, Md.

The Advisory Committee was asked to consider the desirability of class labeling for antihypertensive drugs. Antihypertensive drugs, with few exceptions, have no clinical outcomes claims in their labeling because approval of these agents is usually based on demonstration of efficacy at lowering blood pressure, not reducing morbidity or mortality. Initial placebo-controlled trials of antihypertensive agents were conducted more than 2 decades ago. Accordingly, it has been considered ethically inappropriate to perform placebo-controlled studies of modern antihypertensive agents. These factors have resulted in a clinical conundrum in which agents believed to be highly effective at reducing morbidity and/or mortality cannot claim such benefits. The Advisory Committee meeting was convened to consider how labeling should address the relationship between blood pressure and outcome. The committee felt strongly that not having outcome data available in antihypertensive drugs labels prevents optimal education of practitioners regarding the benefits of important therapeutic agents. Several committee members pointed out that undertreatment of blood pressure remains a major health problem that might be addressed by more descriptive class labeling of antihypertensive agents. The committee agreed that scientific knowledge about antihypertensive drugs is extensive and that lowering blood pressure represents one of the best-studied surrogate outcome measures in clinical medicine. However, the committee expressed some concern regarding “unintended consequences” of class labeling and discussed the need for robust preapproval safety studies and postmarketing surveillance. The industry representative on the committee cautioned that class labeling might represent a disincentive to the pharmaceutical industry to engage in future clinical trials. The committee reviewed the effects of blood pressure reduction on specific cardiovascular and renal outcome measures. After considerable discussion, the committee agreed that reduction in the incidence of stroke and myocardial infarction is the most clearly attributable benefits of blood pressure reduction. Evidence for reduction in cardiovascular mortality and renal disease …

Nocturnal fall of blood pressure with antihypertensive therapy and recurrence of ischaemic stroke: ‘the lower the better’ revisited

Nocturnal fall of blood pressure with antihypertensive therapy and recurrence of ischaemic stroke: ‘the lower the better’ revisited

Pressure dependence of superconducting and magnetic critical temperatures in the ruthenocuprates

We study the dependence on filling and pressure of the superconducting and ferromagnetic critical temperatures of the ruthenocuprates, within the two-band model. At zero pressure, we find separate regions of coexistence of superconductivity and ferromagnetism as a function of filling, with contiguous regions merging together as pressure increases. As a function of pressure, a stronger enhancement of the magnetic phase results in a reduced pressure effect on the superconducting critical temperature. Comparison with recent experiments on the determination of the critical temperatures as a function of the pressure is also discussed.

How to control measurement variation in estimating the mean intraocular pressure reducing effect at a specific point in time

Objective To clarify how to control measurement variation in estimating the mean intraocular pressure reducing effect at a specific point in time. Methods A set of 629 open-angle glaucoma or ocular hypertensive patients, eligible for treatment in both eyes, previously untreated, were reanalyzed at 3 or 6 months of intraocular pressure (IOP) reducing treatment. The trial design had parallel treatment groups; one group receives treatment A and the other group receives treatment B. The standard deviation (SD) of the IOP response variable was calculated based on a single eye per patient, mean of right and left eye (bilaterally identical treatment within each group) or difference between right and left eye (paired-eye difference within each group; one eye receives active treatment and the other eye receives placebo). The effect of using mean of replicated recordings on the SD of the patient group mean IOP was also studied. The results were generalized by applying a measurement variation model. Results The “paired-eye difference within each group” design was clearly most effective; the SD of the IOP response variable was 2.2 mm Hg. Using mean of the right and left eye in a “design with bilaterally identical treatment in each group” was the next best solution; the SD of the IOP was 3.0 mm Hg. The SD of the IOP was 3.2 to 3.4 mm Hg when based on a single eye per patient. The minimization of the SD gave important reduction of number of patients required to enroll in a new trial. Using a single IOP recording per patient produced similar SD of the patient group mean IOP as using mean of replicated IOP recordings when measured with Goldmann tonometry. Conclusion Calculating the mean IOP by using measurements from both eyes of the patient gives important reduction of the variability.

Proteinuria reduction and progression to renal failure in patients with type 2 diabetes mellitus and overt nephropathy

Little is known of the effects of blood pressure reduction by specific classes of antihypertensive drugs on the association between proteinuria reduction and progression of kidney insufficiency and development of end-stage kidney disease in patients with overt diabetic nephropathy in type 2 diabetes mellitus. Associations between baseline proteinuria and proteinuria reduction by either irbesartan, amlodipine, or control for similar decrements in blood pressure and the cumulative incidence of renal end points were examined using the Kaplan-Meier method in patients enrolled in the Irbesartan Diabetic Nephropathy Trial. Risk for kidney failure doubled for each doubling of baseline proteinuria level (hazard ratio, 2.04; 95% confidence interval, 1.87 to 2.22; P < 0.001). For each halving of proteinuria level between baseline and 12 months with treatment, risk for kidney failure was reduced by more than half (hazard ratio, 0.44; 95% confidence interval, 0.40 to 0.49; P < 0.001). For the same proportional change in proteinuria, the reduction in risk for kidney failure was significantly greater for irbesartan compared with amlodipine ( P = 0.048), but not control ( P = 0.245). Proteinuria reduction in the first 12 months of therapy with irbesartan is associated with 36% of the total renoprotective effect observed. Baseline proteinuria is an important risk factor for kidney failure and provides a means to identify patients at greatest risk. Halving proteinuria halves the kidney risk. Proteinuria reduction using an angiotensin receptor-blocking agent, such as irbesartan, should be regarded as an important therapeutic goal in renoprotective strategies.

Antioxidant and Cardioprotective Properties of the Sulphydryl Angiotensinconverting Enzyme Inhibitor Zofenopril

Zofenopril, a new potent sulphydryl angiotensin-converting enzyme (ACE) inhibitor, is characterized by high lipophilicity, selective cardiac ACE inhibition, and antioxidant and tissue protective activities. In vitro and in vivo experiments suggest that zofenopril exerts antioxidant properties at clinically achievable tissue concentrations. In endothelial cells, zofenopril enhances nitric oxide production, attenuates atherosclerotic lesion development and inhibits adhesion molecule expression by reducing reactive oxygen species. These peculiar characteristics are reflected in the drug's cardioprotective activity, which has been shown to be greater than that of non-sulphydryl ACE inhibitors. Cardiac hypertrophy was also reduced by chronic zofenopril administration, independently of its blood pressure-reducing effect. ACE inhibitors with a sulphydryl group could have an advantage in improving vascular function and reducing cardiac impairment compared with non-sulphydryl-containing ACE inhibitors. This could explain zofenopril's remarkable clinical efficacy post-infarction, and potentially beneficial use in prevention and therapy of cardiovascular diseases, such as atherosclerosis, thrombosis and heart failure.

Latanoprost eye drops increase concentration of glycosaminoglycans in posterior rabbit sclera.

Glycosaminoglycans are important components of ocular tissues such as the sclera. The pressure reducing effect of a new antiglaucoma drug, latanoprost, is based on an increase in the uveo-scleral outflow by way of modulation of the intracellular matrix of the ciliary body. The purpose of the study was to test the effect of latanoprost on the content of glycosaminoglycans in rabbit cornea and sclera. Twelve rabbits were studied. Six rabbits were treated for 12 weeks with latanoprost eye drops and 6 with hydroxypropylmethylcellulose, dextran 70 eye drops for control. Samples were taken from cornea and anterior, lateral, and posterior sclera. Glycosaminoglycans were determined quantitatively by spectrophotometry (uronic acids). A significant increase in the concentration of uronic acids was found in all three localisations of sclera from latanoprost-treated animals. The increase was 26%, 24%, and 20% in anterior, lateral, and posterior sclera, respectively. Long-term treatment with latanoprost induces biochemical changes in sclera. The results indicate that topically applied latanoprost reaches the posterior parts of the rabbit eye.

The pressure reduction effect in smooth piping elbows—revisited

The aim of this paper is to revisit the pressure reduction effect in smooth piping elbows under moment loading. A brief review of historical studies and an explanation of the origins of the effect is followed by an overview of an extensive series of detailed finite element analyses, carried out by the authors, which re-examines the well known Rodabaugh and George design factors that are widely used in piping Design Codes.

Effect of Acute Blood Pressure Reduction on Oxygen Uptake Kinetics at the Onset of Exercise in Hypertensive Patients

The aim of the present study was to investigate the adverse effects of hypertension on the cardiovascular system in daily activities and the effect of acute blood pressure reduction on oxygen (O(2)) uptake kinetics. Twenty hypertensive patients were included in the study group. Patients performed treadmill exercise tests (2.5 km/hour and 5 inclines) twice, before and after blood pressure reduction with sublingual captopril. In the control group, ten hypertensive patients underwent two tests one hour apart without blood pressure reduction brought about by drug therapy. The changes in O(2) kinetic values (O(2) deficit and mean response time [MRT]) between the two tests were investigated. In the study group, the O(2) deficit and MRT values measured during the first exercise testing were found to be 547 +/- 183 mL and 40 +/- 9 seconds, while those in the second exercise testing were 401 +/- 127 mL and 34 +/- 7 seconds, respectively. In the control group, the O(2) deficit and MRT values measured during the first exercise test were 491 +/- 217 mL and 42 +/- 16 seconds and 515 +/- 159 mL and 41 +/- 13 seconds in the second exercise test. The differences in O(2) deficit and MRT in the study group were considered to be statistically significant (P = 0.008 and P = 0.004, respectively). Based on our findings, there was a significant improvement in O(2) kinetic values with an acute reduction in blood pressure in hypertensive patients, most likely as a result of an improved response in cardiac output.

Factors associated with long-term progression or stability in exfoliation glaucoma.

To evaluate the effect of intraocular pressure (IOP) reduction on long-term progression or stability in patients with exfoliation glaucoma. Multicenter (Greece, Spain, Russia, and Hungary), retrospective analysis. Medical record analysis of 167 patients with at least 5 years of follow-up, who were stable (n = 85) or whose condition had progressed (n = 82) after the beginning of the follow-up period. The mean +/- SD IOP was 18.1 +/- 2.6 mm Hg in the stable group and 20.1 +/- 4.3 mm Hg in the progressed group (P<.001). The mean +/- SD follow-up time was 6.1 +/- 2.3 years for the stable group and 3.4 +/- 1.7 years for the progressed group. The mean SD for each patient's average IOP was 2.9 mm Hg for the stable group and 4.6 mm Hg for the progressed group (P<.001). Twenty-eight percent of patients who had a mean IOP of 17 mm Hg or lower, 43% of those with an IOP of 18 to 19 mm Hg, and 70% of those with an IOP of 20 mm Hg or higher progressed. Progressed patients had statistically greater optic disc damage at baseline and more medication changes and trabeculectomies during follow-up than stable patients (P<.05). This study suggests that IOP reduction helps to prevent glaucoma progression in patients with exfoliation glaucoma, although it does not guarantee the prevention or worsening of the disease.

Difference-frequency-generator�??based spectrometer at 3 μm for high-sensitivity C2H2 and H2O detection

We detect acetylene and water-vapor lines by using a difference-frequency generator in the spectral region around 3 mm. Both C2H2 and H2O lines belong to fundamental vibrational bands and exhibit a line strength of the order of 10-20 cm/mol. Acetylene molecules were detected either by pure absorption or by first-derivative wavelength-modulation spectroscopy. The minimum detection sensitivity achieved for C2H2 in nitrogen was 4 ppb (parts in 109). Moreover, we discuss the effects of C2H2 pressure reduction in the presence of nitrogen in order to estimate systematic errors in the concentration measurements. Finally, we tested the accuracy of our spectrometer by detecting water vapor present as an impurity in a nitrogen cylinder at a nominal concentration of approximately 5 ppm.

Effects of the flavonoid quercetin and its methylated metabolite isorhamnetin in isolated arteries from spontaneously hypertensive rats.

Chronic oral quercetin exerts antihypertensive effects in spontaneously hypertensive rats (SHR). In the present study, the vasodilator effects of the flavonoid quercetin and its main metabolite isorhamnetin were analysed in isolated thoracic aorta, iliac artery and on the isolated perfused mesenteric resistance vascular bed from SHR and normotensive Wistar Kyoto rats (WKY). In noradrenaline-precontracted vessels from SHR there was an inverse correlation between the relaxant potency (pIC50) of quercetin (4.76 +/- 0.02, 5.08 +/- 0.12, 5.30 +/- 0.18, in aorta, iliac arteries and mesentery, respectively) and isorhamnetin (4.90 +/- 0.11, 5.38 +/- 0.15 and 5.80 +/- 0.10, respectively) and the diameter of the vessel studied. Both flavonoids were more potent in endothelium-denuded aortae and iliac arteries from SHR than from normotensive WKY rats. In addition, in aortae from SHR both flavonoids restored the endothelial-dependent vasodilation. Isorhamnetin, but not quercetin, also reduced the endothelium-dependent contractile responses induced by acetylcholine. These direct vasodilator effects, together with the improvement of endothelial function, are good candidates to explain the blood pressure reduction and vascular protective effects of quercetin in animal models of hypertension and possibly in human cardiovascular diseases.

The effects of dual blockade of the renin- angiotensin system on urinary protein and transforming growth factor-b excretion in 2 groups of patients with IgA and diabetic nephropathy

The therapeutic benefits of dual blockade of the renin-angiotensin system (RAS) have been inconsistent on renal function and proteinuria. To know the contribution of the heterogeneity of study subjects to such inconsistency, we evaluated the effects of dual blockade of RAS in 2 groups of selected renal diseases, IgA and diabetic nephropathy. To avoid confounding by the blood pressure-reducing effects, angiotensin II receptor antagonists (ATRAs) were added on the patients with long-term, optimally controlled blood pressure taking ACE inhibitors. Twenty-four-hour urinary protein excretion rate and urinary TGF-beta1 level were measured as surrogate markers of renal injury. We conducted a prospective crossover trial with 14 IgA and 18 type-2-diabetic nephropathy patients showing moderate degree of proteinuria (> or = 1.0 g/day) and renal dysfunction (creatinine clearance 25 - 75/ml/min). Four to 8 mg once-daily dose of candesartan and placebo were alternatively added on ramipril dose of 5 - 7.5 mg/day for 16 weeks. All baseline data except for the age factor were statistically the same between the 2 disease groups. Twenty-four-hour mean arterial blood pressures were 91.2 +/- 1.6 and 92.3 +/- 1.8 mmHg in IgA and diabetic nephropathy patients respectively at baseline (p = NS). Mean arterial pressure did not change by the addition of candesartan or placebo in both groups. The addition of candesartan (combination) reduced 24-hour urinary protein excretion rate in IgA nephropathy patients with a mean change of -12.3 +/- 4.5%, which is significantly greater compared to a mean change of -0.1 +/- 3.3% after the addition of placebo (placebo) (mean difference 12.4 +/- 5.0, 95% CI 1.2 - 23.5; p < 0.05). Urinary TGF-beta1 level was reduced considerably by the combination therapy, with a -28.9 +/- 6.0% decrease, which was significantly different to that by the placebo, with +4.3 +/- 12.4% (33.3 +/- 13.5, 3.2 - 63.3; p < 0.05). In diabetic nephropathy patients, the addition of candesartan did not reduce 24-hour urinary protein excretion rate. Mean changes of 24-hour urinary protein excretion rate were -0.8 +/- 4.7% by the combination therapy and +0.5 +/- 6.1% by placebo (mean difference 1.3 +/- 4.7, 95% CI -6.8 - 13.5; p < NS). The level of urinary TGF-beta1 was reduced by the combination therapy, with -14.3 +/- 9.5% decrease, but it did not reach statistical significance compared to placebo of +0.7 +/- 15.5% (15.0 +/- 13.5, -14.4 - 44.5; p < NS). The changes in 24-hour urinary protein excretion rate and urinary TGF-beta1 level were neither correlated with each other, nor with the change in mean arterial pressure. Significant changes in the renal function were not detected during the study period. Definite beneficial effects of dual blockade of RAS on proteinuria and TGF-beta1 excretion were found in IgA nephropathy patients, which was independent of blood pressure-reducing effect. With our 16-week trial, such benefits were not observed in type 2 diabetic nephropathy. The reduction in urinary TGF-beta1 level suggests that the combination therapy may provide additional renoprotection through the antisclerosing effects. Based on our results, for a proper interpretation the therapeutic effects of the combination therapy should be evaluated separately according to the underlying renal disease.

Successful treatment of renovascular hypertension has no effect on insulin sensitivity.

The association of insulin resistance (IR) and essential hypertension is well known, but a causal relationship has not been proven. Patients with secondary hypertension as a result of renal artery stenosis (RAS) usually do not reveal IR, but no study has addressed the effect of blood pressure reduction after successful treatment of RAS on insulin sensitivity and glucose effectiveness. The insulin sensitivity index (SI) and glucose effectiveness (SG) were measured before and after successful intervention of an angiographically proven significant RAS in 18 out of 23 patients (eight males/10 females; mean age 51.5 +/- 13.1 years) in which improvement/cure of arterial hypertension was achieved. After a mean of 10.7 months, patients were reevaluated for 24-h blood-pressure measurement, kidney function, adrenaline, noradrenaline, plasma-renin-activity (PRA), aldosterone, atrial natriuretic peptide (ANP) and cyclic guanosine monophosphate (cGMP), and glucose metabolism parameters such as basal insulin, glucose disappearance constant (K-value), SI and SG. For calculation of SI and SG, insulin and glucose data from the modified frequent sampling intravenous glucose tolerance test (FSIGT) were submitted to the MINMOD program. After intervention, systolic 24-h blood pressure had decreased from 156.1 +/- 16.4 mmHg to 139.9 +/- 15.1 mmHg, and diastolic 24-h blood pressure from 97.1 +/- 14.7 mmHg to 87.3 +/- 13.4 mmHg. No significant change in SI (before 4.3 +/- 2.0, after 4.8 +/- 2.0 min(-1) per microU mL(-1)) or SG (before 1.55 +/- 0.42x10(-2) min(-1), after 1.8 +/- 0.48x10(-2) min(-1)) was observed. Aldosterone decreased from 246.7 +/- 180.7 to 115 +/- 61.4 (P=0.009) as PRA decreased from 12.4 +/- 11.4 to 4.2 +/- 7.6 ng mL h(-1) (P=0.01). Creatinine clearance, and adrenaline and noradrenaline levels as well as ANP and cGMP did not change after treatment for RAS. Subsequent to the definition of IR (SI < or =3.2x10(-4) min(-1) per microU mL(-1)) some differences among these two subgroups (SI < or =3.2, or SI>3.2) could be found. Patients with IR (n=8) were characterized by a higher body mass index (BMI), higher basal insulin values and significantly lower cGMP values. Only the group without IR (n=10) developed significant improvement of systolic blood pressure. We conclude that blood pressure reduction by treatment of RAS does not alter insulin action and that there is no link between the circulating concentrations of renin/aldosterone and glucose metabolism in renovascular hypertension (RVH). The results do not support the hypothesis of a direct link between blood pressure in RVH and the individual state of insulin sensitivity. However, patients with a normal SI are more likely to experience an almost normalization of arterial blood pressure after treatment for RAS.

Antihyperglycemic and blood pressure-reducing effects of stevioside in the diabetic Goto-Kakizaki rat

Stevioside, a glycoside present in the leaves of the plant, Stevia rebaudiana Bertoni (SrB), has acute insulinotropic effects in vitro. Its potential antihyperglycemic and blood pressure–lowering effects were examined in a long-term study in the type 2 diabetic Goto-Kakizaki (GK) rat. Rats were fed 0.025 g · kg−1 · d−1 of stevioside (purity > 99.6%) for 6 weeks. An intra-arterial catheter was inserted into the rats after 5 weeks, and conscious rats were subjected to arterial glucose tolerance test (2.0 g · kg−1) during week 6. Stevioside had an antihyperglycemic effect (incremental area under the glucose response curve [IAUC]): 985 ± 20 (stevioside) versus 1,575 ± 21 (control) mmol/L × 180 minutes, (P <.05), it enhanced the first-phase insulin response (IAUC: 343 ± 33 [stevioside] v 136 ± 24 [control] μU/mL insulin × 30 minutes, P <.05) and concomitantly suppressed the glucagon levels (total AUC: 2,026 ± 234 [stevioside] v 3,535 ± 282 [control] pg/mL × 180 minutes, P <.05). In addition, stevioside caused a pronounced suppression of both the systolic (135 ± 2 v 153 ± 5 mm Hg; P <.001) and the diastolic blood pressure (74 ± 1 v 83 ± 1 mm Hg; P <.001). Bolus injections of stevioside (0.025 g · kg−1) did not induce hypoglycemia. Stevioside augmented the insulin content in the β-cell line, INS-1. Stevioside may increase the insulin secretion, in part, by induction of genes involved in glycolysis. It may also improve the nutrient-sensing mechanisms, increase cytosolic long-chain fatty acyl-coenzyme A (CoA), and downregulate phosphodiesterase 1 (PDE1) estimated by the microarray gene chip technology. In conclusion, stevioside enjoys a dual positive effect by acting as an antihyperglycemic and a blood pressure–lowering substance; effects that may have therapeutic potential in the treatment of type 2 diabetes and the metabolic syndrome. Copyright 2003, Elsevier Science (USA). All rights reserved.

Evaluation of the Recycling of biomass resources by using the waste accout

A part of biomass resources are used for agricultural production and are recycled for materials of other activities, such as compost made from livestock excrement or rice plant straw used for litter. However, these activities are not revealed in economic statistics because of bartering and trading without any charge. It is necessary to understand transactions of biomass resources in agricultural sector properly.The purpose of this soudy is to propose an accounting system for evaluating biomass resources used in the agricultural sector, as well as to understand the status of wastes and environmental pressure arising from agricultural production.The waste acounting system can be adapted to the case of the agricultural sector to grasp the status of transactions of organic resources. It can also show the amount of environmental pressure arising from agricultural production in addition to the amount of biomass resources and their disposal and recycling. Finally, as an example of the use of information obtained from the accounting system, reducing environmental pressure is estimated if imported rice plant straw is substituted for domestic supplies.The results of the analysis are 1) Environmental pressure reduction due to reduction of burnt straw is 2, 089 ton-SPM, 1, 572 ton-CH4 and 25 ton-N2O in the case without regional constraint of straw supply, 2) When considering the regional constraint of the straw supply, the effect is reduced to 71% of the total. 3) Chubu area shows the largest effect of environmental pressure reduction.