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Plasma Profile (plasma + profile)
Selected AbstractsUsing the Steepened Plasma Profile and Wave Breaking Threshold in Laser-Plasma InteractionCONTRIBUTIONS TO PLASMA PHYSICS, Issue 8 2008P. Zobdeh Abstract In this work we evaluate the interaction of high intense laser beam with a steepened density profile. During laser interaction with underdense plasma by freely expanding plasma regime, modification of density profile is possible. In this paper we have investigated the ultra short laser pulse interaction with nonisothermal and collisionless plasma. We consider self,focusing as an effective nonlinear phenomenon that tends to increase when the laser power is more than critical rate. By leading the expanded plasma to a preferred location near to critical density, laser reflection is obtained, so the density profile will be locally steepened. The electromagnetic fields are evaluated in this new profile. We show the amplitude and period of electrical field oscillation are increased by reducing the steepened scale length. Also our numerical results identify that by reducing the steepened scale length, the electrical field is increased to wave breaking threshold limit. This high gradient electrical field causes the effective beam loading during the wave breaking phenomenon. The wave breaking can be the initial point for other acceleration regime as cavity or channel guiding regime. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Plasma profile and pharmacokinetics of dextromethorphan after intravenous and oral administration in healthy dogsJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2004B. KuKanich Dextromethorphan is an N -methyl- d -aspartate (NMDA) noncompetitive antagonist which has been used as an antitussive, analgesic adjunct, probe drug, experimentally to attenuate acute opiate and ethanol withdrawal, and as an anticonvulsant. A metabolite of dextromethorphan, dextrorphan, has been shown to behave pharmacodynamically in a similar manner to dextromethorphan. The pharmacokinetics of dextromethorphan were examined in six healthy dogs following intravenous (2.2 mg/kg) and oral (5 mg/kg) administration in a randomized crossover design. Dextromethorphan behaved in a similar manner to other NMDA antagonists upon injection causing muscle rigidity, ataxia to recumbency, sedation, urination, and ptyalism which resolved within 90 min. One dog repeatedly vomited upon oral administration and was excluded from oral analysis. Mean ± SD values for half-life, apparent volume of distribution, and clearance after i.v. administration were 2.0 ±0.6 h, 5.1 ± 2.6 L/kg, and 33.8 ± 16.5 mL/min/kg. Oral bioavailability was 11% as calculated from naïve pooled data. Free dextrorphan was not detected in any plasma sample, however enzymatic treatment of plasma with glucuronidase released both dextromethorphan and dextrorphan indicating that conjugation is a metabolic route. The short half-life, rapid clearance, and poor bioavailability of dextromethorphan limit its potential use as a chronic orally administered therapeutic. [source] Insulin and glucose profiles during continuous subcutaneous insulin infusion compared with injection of a long-acting insulin in Type 2 diabetes1DIABETIC MEDICINE, Issue 5 2008T. Parkner Abstract Aims To compare insulin and glucose profiles during basal continuous subcutaneous infusion of a rapid-acting insulin analogue and once daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes. Methods Twenty-one patients with Type 2 diabetes treated with oral glucose-lowering agents were randomized in this two-period crossover study to an equivalent 24-h dose of continuous subcutaneous infusion of insulin aspart and subsequently once-daily bedtime subcutaneous injection of insulin glargine, or vice versa, for eight consecutive days. Plasma profiles of insulin and glucose were recorded. Results On the last day of each treatment period, the area under the curve (AUC) for glucose was 10% lower on the continuous subcutaneous infusion regimen compared with the insulin injection regimen (P = 0.002). This was accomplished by a flat exogenous insulin infusion profile compared with a peaking profile with injected insulin (AUC was 74% higher after injection compared with pre-injection levels (P = 0.001)). During the last 6 days in each treatment period, the intra-subject variability of exogenous fasting insulin levels in the mornings was 41% lower during insulin infusion compared with insulin injection (P = 0.012). The corresponding intra-subject variability for fasting glucose only showed a tendency to be lower during infusion as compared to the injection regimen (28%; P = 0.104). Thirteen symptomatic-only or minor hypoglycaemic episodes were recorded during the entire infusion period compared with three episodes during the injection period. Conclusions Basal continuous subcutaneous infusion of a rapid-acting insulin analogue improved plasma insulin (more flat insulin profile with a lower variability) and glucose (lower AUC) profiles compared with once-daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes. [source] Plasma urocortin in acute myocardial infarction patientsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2010Arintaya Phrommintikul Eur J Clin Invest 2010; 40 (10): 874,882 Abstract Background, Despite its proposed cardioprotective effect, the role of plasma urocortin in acute myocardial infarction (AMI) remains unknown. We investigated plasma profile of urocortin in AMI patients and evaluated its long-term prognostic performance. Material and methods, Sixty-six AMI patients and 21 healthy subjects were included in this study. Blood samples for urocortin were collected on days 0 (onset), 1, 3 and 5 and at 3 and 6 months. Primary endpoint was mortality within 1 year of follow-up. Secondary endpoint was combined death and nonfatal adverse cardiac events (i.e. myocardial reinfarction, urgent revascularization or hospitalization due to heart failure) within 1 year. Results, During follow-up at 1 year, 38 (57·6%) patients were alive without cardiac events, nine (13·6%) had nonfatal cardiac events and 17 (25·8%) died. Plasma urocortin in AMI patients were increased on days 0, 1, 3 and 5 (P < 0·05 vs. control). The receiver-operating characteristic curve showed an area under curve (AUC) of day 0 urocortin to be 0·750 with 95% confidence interval (CI) of 0·619,0·881 (P = 0·004), whereas AUC of NT-proBNP was 0·857 (95% CI, 0·722,0·992; P = 0·003). Sensitivity values for predicting the mortality of urocortin NT-proBNP and a combined urocortin and NT-proBNP were 0·81 (95% CI, 0·54,0·95), 0·86 (95% CI, 0·42,0·99) and 1·0 (95% CI, 0·56,1·0), respectively. Conclusions, Plasma urocortin level is elevated in AMI patients for 5 days from onset. High plasma urocortin within 24 h after the onset is associated with increased mortality. Combined urocortin and NT-proBNP enhance prognostic performance in AMI patients. [source] Licking induced changes to the pattern of moxidectin milk elimination after topical treatment in dairy cowsJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2009F. IMPERIALE Pour-on administration of the macrocyclic lactones anti-parasitic compounds in beef and dairy cattle is now worldwide accepted. However, the information available on their milk excretion pattern, after topical administration is rather limited. Additionally, the cattle licking behaviour has been proven to affect the kinetics of these anti-parasitic compounds. The purpose of this study was to investigate the influence of the natural licking behaviour on the plasma and milk disposition of moxidectin (MXD), topically administered (500 ,g/kg) in lactating dairy cows. Ten lactating Holstein dairy cows (705 kg body weight) were allocated into two experimental groups (n = 5). The licking was prevented during 5 days postadministration in animals in group I, and the remaining cows (group II) were allowed to lick freely. MXD concentrations profiles were measured in plasma and milk over 15 days posttreatment. The licking restriction period caused marked changes in MXD disposition kinetics both in plasma and milk. Both plasma and milk MXD concentrations (partial AUC 0,5 days) were significantly lower (P < 0.05) in licking-restricted cows. After the 5-day of restriction period, the animals were allowed to lick freely, which permitted the oral ingestion of MXD, situation clearly reflected both in plasma profile and milk excretion pattern. Despite the enhanced MXD milk concentrations measured in free-licking cows, drug concentrations did not reach the maximum MXD residues limit. [source] The detection of phenotypic differences in the metabolic plasma profile of three strains of Zucker rats at 20 weeks of age using ultra-performance liquid chromatography/orthogonal acceleration time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2006Robert S. Plumb Analysis of biological fluids using ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) (metabonomics) can allow new insights to be gained into disease processes, with advances in chromatographic techniques enabling the detection of thousands of metabolites. In this work metabonomics has been used to investigate the metabolic processes involved in type II diabetes in the Zucker obese rat. Plasma was analyzed from three different strains, the Zucker (fa/fa) obese, Zucker lean and the lean/(fa) obese cross. Using UPLC/MS, ca. 10,000 ions were detected due to the narrow peak widths and excellent peak shapes achieved with this technology. Confidence in the chromatographic performance was demonstrated by the use of quality control standards. The positive and negative ion total ion chromatograms obtained from the three strains were readily distinguishable using multivariate statistical analysis. The greatest difference was observed between the Zucker lean and Zucker lean/(fa) rats compared to the Zucker (fa/fa) obese rats. Positive ions m/z 220 (4.36,min), 282(3.78,min), 359 (5.33,min) and 405 (7.77,min) were elevated in the plasma derived from Zucker lean rats whilst ions m/z 385 (6.80,min) and 646 (4.36,min) were at a lower concentration compared to the plasma from the Zucker (fa/fa) obese animals. Negative ions elevated in the Zucker lean rats included m/z 212 (2.30,min), 514 (2.85,min), 295 (4.39,min), 329 (3.11,min), 343 (2.86,min) and 512 (2.86,min) with ions m/z 538 (4.18,min), 568 (4.18,min), 568 (5.09,min) and 612 (4.30,min) being raised in the samples derived from Zucker (fa/fa) obese animals. The ion m/z 514 (3.85,min) was found to correspond to taurocholate, providing further support for an involvement of taurine metabolism in diabetes. Copyright © 2006 John Wiley & Sons, Ltd. [source] The effect of hepatic passage on postprandial plasma lipid profile of rainbow trout (Oncorhynchus mykiss) after a single mealAQUACULTURE NUTRITION, Issue 5 2010E.J. ELIASON Abstract For the first time, pre- and post-hepatic plasma lipid profiles were monitored following a single meal in a free-swimming, non-anaesthetized fish. Rainbow trout (Oncorhynchus mykiss; 700,1500 g; 10 °C) were equipped with cannulae in the dorsal aorta (DA) and hepatic portal vein (HPV). Simultaneous blood samples, taken from both cannulae at 0, 3, 6, 12, 24 and 48 h postprandial, revealed the time course of the plasma lipid profiles following a single meal (1% of body mass). Primarily monounsaturated fatty acids with the exception of 18:1n , 9, increased significantly from baseline by 12 h postprandial without greatly affecting total plasma lipid concentrations. Total plasma lipids then showed a small peak at 24 h postprandial, coinciding with a peak in triacylglycerols. We conclude that assimilation of lipids from the digest into the plasma is slower than reported for proteins and carbohydrates in the same species. Furthermore, as there were no significant differences between the HPV and DA, no measurable effect of hepatic passage on plasma lipid levels was resolved. Therefore, we also conclude that, in contrast to that in higher vertebrates, hepatic passage does not seem to have a major role in rainbow trout for modulating the postprandial plasma profile of lipids. [source] Efficacy against Fasciola hepatica and the pharmacokinetics of triclabendazole administered by oral and topical routesAUSTRALIAN VETERINARY JOURNAL, Issue 5 2009PJ Martin Objective To determine the efficacy of triclabendazole (TCBZ) against 28-day-old, early immature liver fluke in cattle and its pharmacokinetics following administration by the oral or topical (pour-on) route. Procedures Cattle (n = 18) were infected with 500 TCBZ-susceptible liver fluke metacercariae and randomly allocated to three groups. At 28 days after infection, the groups were: (1) untreated controls; (2) treated with oral TCBZ at 12 mg/kg in combination with oxfendazole and selenium (TOS); (3) treated with pour-on TCBZ at 30 mg/kg in combination with abamectin (TA). Blood samples were taken immediately prior to treatment and serially after treatment to assess the plasma profile of TCBZ metabolites. Ten weeks after treatment all animals were slaughtered and total liver fluke counts, fluke egg counts and liver pathology were assessed. Results Both the TOS and TA treatments resulted in significant reductions of 28-day-old liver fluke, as assessed by fluke counts and fluke egg counts at slaughter, and the reductions following TOS treatment were significantly greater than those following TA treatment. The blood profile of TCBZ metabolites in TOS-treated animals showed a significantly greater area under the plasma concentration time curve and a higher maximum observed concentration than those treated with TA. There was significantly less liver pathology in TOS-treated animals than in the TA-treated animals. Conclusion TCBZ administered orally at 12 mg/kg resulted in greater efficacy against 28-day-old, early immature liver fluke than was achieved by topical administration at 30 mg/kg. Plasma metabolites of TCBZ were higher and liver pathology was less in TOS-treated animals than in TA-treated animals. [source] Multi-Fluid Modeling of Low-Recycling Divertor RegimesCONTRIBUTIONS TO PLASMA PHYSICS, Issue 3-5 2010R. D. Smirnov Abstract The low-recycling regimes of divertor operation in a single-null NSTX magnetic configuration are studied using computer simulations with the edge plasma transport code UEDGE. The edge plasma transport properties pertinent to the low-recycling regimes are demonstrated. These include the flux-limited character of the parallel heat transport and the high plasma temperatures with the flattened profiles in the scrape-off-layer. It is shown that to maintain the balance of particle fluxes at the core interface the deuterium gas puffing rate should increase as the divertor recycling coefficient decreases. The radial profiles of the heat load to the outer divertor plate, the upstream radial plasma profiles, and the effects of the cross-field plasma transport in the low-recycling regimes are discussed. It is also shown that recycling of lithium impurities evaporating from the divertor plate at high surface temperatures can reverse the low-recycling divertor operational regime to the high-recycling one and may cause thermal instability of the divertor plate (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Transdermal delivery system for zidovudine: in vitro, ex vivo and in vivo evaluationBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 1 2004Sunil Thomas Kumar Narishetty Abstract The objective of this study was to prepare a transdermal delivery system (TDS) for zidovudine (AZT) with a combination of menthol and oleic acid as penetration enhancers incorporated in hydroxypropyl methylcellulose, and to evaluate ex vivo as well as in vivo permeation across rat skin. It was found that AZT in gel formulation was stable in both refrigerated as well as accelerated stability conditions for 3 months and further, the gel did not significantly retard the permeability of AZT across the skin in comparison with solution formulation. Ex vivo steady state flux of AZT across rat skin from gel was 2.26 mg cm,2 h,1, which is sufficient to achieve therapeutic plasma concentrations. Intravenous pharmacokinetic parameters of AZT in rats were determined and used together with ex vivo flux data to generate theoretical plasma profiles of AZT and compared with plasma concentrations achieved after application of TDS. Further, steady state plasma concentrations of drug following multiple applications of TDS were determined and good correlations between ex vivo and in vivo data were observed. In addition, the combination of penetration enhancers used at 2.5% w/w in this study proved efficient in achieving sufficient enhancement in the transdermal permeability of AZT across rat skin with reduced skin irritation potential when compared with individual penetration enhancers at higher concentrations. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||