Low-dose dietary supplementation with omega-3 fish oils in systemic lupus erythematosus not only has a therapeutic effect on disease activity but also improves endothelial function and reduces oxidative stress and may therefore confer cardiovascular benefits.
Background-Impaired endothelium-mediated vasodilatation (EMVD) in congestive cardiac failure (CCF) has been linked to decreased nitric oxide (NO) bioavailability because of its interaction with vascular superoxide (O 2 ·Ϫ ), derived predominantly from NAD(P)H-dependent oxidases. When uncoupled from essential cofactors, endothelial nitric oxide synthase (eNOS) produces O 2 ·Ϫ . We studied the functional consequences of eNOS uncoupling in relation to EMVD in patients with CCF. Methods and Results-We employed the platelet as a compartmentalized ex-vivo model to examine O 2 ·Ϫ and NO production. When eNOS is functioning normally, incorporation of N -Nitro-L-Arginine methyl ester (L-NAME, 1 mmol/L), results in increased O 2 ·Ϫ detection, as inhibition of NO production prevents NO scavenging of O 2 ·Ϫ . This was observed in controls and 9 of the CCF patients, in whom O 2 ·Ϫ detection increased by 63% and 101%, respectively. In the remaining 9 CCF patients, incorporation of L-NAME reduced O 2 ·Ϫ production by 39%, indicating O 2 ·Ϫ production by eNOS uncoupling. Detection of platelet-derived NO was significantly greater in eNOS-coupled platelets compared with the uncoupled group (2.8Ϯ1.4 versus 0.9Ϯ0.4 pmol/10 8 platelets, Pϭ0.04). Endothelium-dependent and -independent vasodilator responses to acetylcholine and sodium nitroprusside recorded using venous occlusion plethysmography were significantly impaired in patients exhibiting eNOS uncoupling. Conclusions-This study provides first evidence that platelet eNOS can become uncoupled in human CCF. Impaired endothelium-dependent and -independent vasodilator responses and diminished platelet-derived NO production occurred in association with enzyme uncoupling.
The pharmacokinetics of a novel praziquantel preparation (Distocide) were investigated in Sudanese patients with hepatosplenic schistosomiasis and in healthy volunteers, and compared with those of Biltricide. The results of the first study indicated greater (P less than 0.05) plasma concentrations of Biltricide at 1.5, 2, 3 and 5 h after administration than with Distocide; plasma elimination half-lives (t 1/2) were not significantly different. In patients with hepatosplenic schistosomiasis, higher plasma levels of Distocide were noted (P less than 0.05 at 8 h) compared to healthy controls; however, due to wide inter-individual variations, there were no significant differences in maximum plasma concentration, time to maximum plasma concentration, area under the plasma concentration curve (AUC), volume of distribution, or clearance; t 1/2 was greater (P less than 0.05) in patients (11.9 +/- 5.4 h) than controls (2.3 +/- 0.4 h). In the presence of food, higher plasma concentrations of Distocide occurred compared to the fasting state; AUCs were greater (P less than 0.01) in both food groups, although the values of t 1/2 were shorter. The lower plasma levels and longer duration of action of Distocide may be advantageous in reducing side effects and prolonging exposure of the schistosomes to the drug.
Objective-Impaired flow-mediated dilation (FMD) occurs in disease states associated with atherosclerosis, including SLE.The primary hemodynamic determinant of FMD is wall shear stress, which is critically dependent on the forearm microcirculation. We explored the relationship between FMD, diastolic shear stress (DSS), and the forearm microcirculation in 32 patients with SLE and 19 controls. Methods and Results-DSS was calculated using (mean diastolic velocityϫ8ϫblood viscosity)/baseline brachial artery diameter. Doppler velocity envelopes from the first 15 seconds of reactive hyperemia were analyzed for resistive index (RI), and interrogated in the frequency domain to assess forearm microvascular hemodynamics. FMD was significantly impaired in SLE patients (median, 2.4%; range, Ϫ2.1% to 10.7% versus median 5.8%; range, 1.9% to 14%; PϽ0.001). DSS (dyne/cm 2 ) was significantly reduced in SLE patients (median, 18.5; range, 3.9 to 34.0 versus median 21.8; range, 14.1 to 58.7; Pϭ0.037). A strong correlation between FMD and DSS, r s ϭ0.65, Pϭ0.01 was found. Postischemic RI was not significantly different between the 2 groups; however, there were significant differences in the power-frequency spectrums of the Doppler velocity envelopes (PϽ0.05). Conclusions-These data suggest that in SLE, altered structure and function of the forearm microcirculation contributes to impaired FMD through a reduction in shear stress stimulus. Key Words: eigenvector Ⅲ flow-mediated dilation Ⅲ microcirculation Ⅲ shear stress Ⅲ systemic lupus erythematosus S ystemic lupus erythematosus (SLE) is the archetypal autoimmune disease, with a wide range of clinical manifestations. Among the clinical challenges of SLE, one of the most compelling is the high incidence of atherosclerosis in young women. In 1976, Urowitz et al showed a bimodal mortality pattern in SLE, with late deaths (comprising 45%) attributed to myocardial infarction. 1 Women with SLE have a high prevalence of coronary artery disease (CAD) 2 and an incidence of myocardial infarction up to 50 times higher than age-matched normals. 3 Classical risk factors are similar to those in the general population, 3 but the increased risk of atherosclerosis is not exclusively related to traditional Framingham risk factors alone, 4 with a recent report highlighting SLE itself as an independent risk. 5 Whereas several studies have highlighted the presence of subclinical atherosclerosis in SLE, 6,7 the pathogenesis is not fully understood. It has been proposed that autoimmune vascular injury in SLE may predispose to atherosclerotic plaque formation through mechanisms that promote endothelial dysfunction, the earliest precursor for plaque development. 8 -10 Flow-mediated dilation of the brachial artery (FMD) is used clinically as an indirect bioassay for endotheliumderived nitric oxide (NO) production. The primary hemodynamic determinant of FMD is wall shear stress, 11-13 and the degree of FMD has been shown to be proportional to both systolic and diastolic shear stress (DSS) in response to incr...
DHA improves NO bioavailability, decreases O(2)(-) production, and blunts VEGF-mediated angiogenic signaling. These findings suggest a role for ω-3 PUFAs, particularly DHA, in maintaining vascular integrity while reducing pathologic retinal neovascularization.
Sotalol, a beta-adrenoceptor blocking drug, was administered to 12 hypertensive pregnant women. The concentration of the drug was assayed in samples of maternal plasma, amniotic fluid and mixed umbilical cord plasma at delivery and, in five mothers who elected to breast feed, in paired samples of maternal plasma and breast milk. Sotalol reduced blood pressure effectively at a mean daily dose of 433.1 & 54 * 1 mg but crossed the placental barrier. The mean maternal: fetal plasma concentration ratio was 1 : 1.05 and the mean amniotic fluid concentration was 7 * 0 & 2 * 7 pg/ml. Delivery occurred at mean gestational age of 37 * 7 I 0 * 7 weeks ; 12 infants were liveborn with a mean weight of 2 . 8 k O . l kg and eight of them had no significant neonatal problems. Of the other four, two died from severe congenital anomalies, one had perinatal asphyxia and one mild transient hypoglycaemia. High sotalol concentrations were found in breast milk (mean plasma : milk ratio was 1 : 5 -4) raising the possibility of pharmacological effect in the newborn infant. The results suggest that sotalol adequately controls blood pressure in hypertension complicating pregnancy but because, unlike results from the pregnant ewe, it crosses the human placental barrier it offers no apparent advantages over other beta-adrenoceptor antagonists.
1 Plasma levels of propranolol were measured at intervals after the oral administration of 160 mg propranolol and 160 mg L.A. propranolol in ten subjects who received both drugs on separate occasions.2 Mean peak plasma concentration of propranolol occurred 2 h after propranolol and 10 h after the L.A. formulation; the peak concentration with the former was four times that with the latter. At 24 h the plasma level was significantly higher after L.A. propranolol. 3 Observations were made in nine healthy volunteers who exercised before and at intervals after the oral administration of 160 mg propranolol and 160 mg L.A. propranolol.4 Propranolol produced a maximum reduction (27.84 + 2.4%) in the exercise tachycardia at 3 h and L.A. propranolol a maximum reduction (22.00 + 1.73%) at 6 h. The effects at 24 h were 9.24 + 1.55 and 16.79 + 2.16% respectively.5 Five subjects were given 160 mg propranolol as a single dose daily for 8 days and on a separate occasion similar treatment with L.A. propranolol. Subjects were exercised and blood samples were taken before and 3 h after each dose on days 1 to 5 and on day 8. propranolol were 12.5 to 17.5 (trough values) and 18.4 to 50.0 (peak values) ng/ml. 8 These observations show that the new long acting formulation of propranolol produces a significant reduction of an exercise tachycardia throughout a 24 h period without a very high initial effect during single and multiple dosing. This formulation should be suitable for once a day administration.
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