Search results for "kinetics"

Enhanced thermodynamic and kinetic stability of calix[4]arene dimers locked in the cone conformation.

2004

Wide rim tetraurea derivatives (2a,b) have been prepared from a calix[4]arene rigidified in the cone conformation by two diethyleneglycol ether bridges between adjacent oxygens. In comparison to the analogous tetraurea derivatives (3a,b) of a tetrapentoxy calix[4]arene, 2a,b show an increased thermodynamic stability in mixtures of CDCl(3) and DMSO-d(6). Their kinetic stability as expressed by the rate of guest exchange (benzene or cyclohexane against the solvent benzene-d(6)) is also strongly increased by factors of 30-38. Noticeable differences for the inclusion of selected guests are found.

Cooperative onset of a different state of water in the presence of macromolecules.

1973

Temperature affects the ontogeny of sexually dimorphic cuticular hydrocarbons inDrosophila melanogaster

2002

0022-0949 (Print) Journal Article Research Support, Non-U.S. Gov't; Hydrocarbons on the cuticle of mature Drosophila melanogaster flies play a crucial role in mate recognition, and protect against dehydration. We measured the effect of temperature on mature cuticular hydrocarbons (CHs) by (i) rearing two control strains at different temperatures, (ii) shifting the temperature after metamorphosis and (iii) inducing a single heat-shock pulse in control and heat-sensitive transgenic strains, over a period of 3 days following adult eclosion. This study describes the time course of the events involved in the production of male- and female-predominant CHs. We also found that 'immature' CHs, sexua…

Epstein-Barr virus DNA load kinetics analysis in allogeneic hematopoietic stem cell transplant recipients: Is it of any clinical usefulness?

2017

Abstract Background There is a lack of clinical information regarding the usefulness of plasma Epstein-Barr virus (EBV) DNA load kinetics analyses in the management of EBV infections in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Namely, it remains unknown whether this type of analysis can help physicians to anticipate the development of high-level EBV DNAemia episodes requiring rituximab treatment or predict the risk of recurrent EBV DNAemia or post-transplant lymphoproliferative disorders (PTLDs). Study design Unicentric, retrospective, observational study including 142 consecutive patients undergoing T-cell replete allo-HSCT. The plasma EBV DNA load was mon…

Bispecific T-Cell Engager (BiTE) Antibody Construct Blinatumomab for the Treatment of Patients With Relapsed/Refractory Non-Hodgkin Lymphoma : Final …

2016

Purpose Blinatumomab is a CD19/CD3 BiTE (bispecific T-cell engager) antibody construct for the treatment of Philadelphia chromosome–negative acute B-lymphoblastic leukemia. We evaluated blinatumomab in relapsed/refractory B-cell non-Hodgkin lymphoma (NHL). Patients and Methods This 3 + 3 design, phase I dose-escalation study determined adverse events and the maximum tolerated dose (MTD) of continuous intravenous infusion blinatumomab in patients with relapsed/refractory NHL. Blinatumomab was administered over 4 or 8 weeks at seven different dose levels (0.5 to 90 μg/m2/day). End points were incidence of adverse events, pharmacokinetics, pharmacodynamics, and overall response rate. Results B…

Myristic acid is associated to low plasma HDL cholesterol levels in a Mediterranean population and increases HDL catabolism by enhancing HDL particle…

2016

Background: HDL-C plasma levels are modulated by dietary fatty acid (FA), but studies investigating dietary supplementation in FA gave contrasting results. Saturated FA increased HDL-C levels only in some studies. Mono-unsaturated FA exerted a slight effect while poly-unsaturated FA mostly increased plasma HDL-C. Aims: This study presents two aims: i) to investigate the relationship between HDL-C levels and plasma FA composition in a Sicilian population following a "Mediterranean diet", ii) to investigate if FA that resulted correlated with plasma HDL-C levels in the population study and/or very abundant in the plasma were able to affect HDL catabolism in an "in vitro" model of cultured hep…

A preclinical study to model taurine pharmokinetics in the undernourished rat

2018

AbstractMalnutrition is a common feature of chronic and acute diseases, often associated with a poor prognosis, including worsening of clinical outcome, owing, among other factors, to dysfunction of the most internal organs and systems affecting the absorption, metabolism and elimination of drugs and nutrients. Taurine is involved in numerous biological processes and is required in increased amounts in response to pathological conditions. The aim of this study was to describe the behaviour of taurine in well-nourished (WN) rats and to analyse the influence of protein–energy undernutrition on the pharmacokinetic (PK) parameters of taurine, using a PK model. Wistar rats were randomly distribu…

Cerebrospinal fluid pharmacokinetics of ceftaroline in neurosurgical patients with an external ventricular drain

2019

IF 5.217; International audience; BackgroundOwing to its antibacterial properties, ceftaroline could be attractive for prevention or treatment of bacterial post-neurosurgical meningitis/ventriculitis. However, few data are available concerning its meningeal concentrations.ObjectivesTo investigate ceftaroline CSF pharmacokinetics in ICU patients with an external ventricular drain (EVD).MethodsPatients received a single 600 mg dose of ceftaroline as a 1 h intravenous infusion. Blood and CSF samples were collected before and 0.5, 1, 3, 6, 12 and 24 h after the end of the infusion. Concentrations were assayed in plasma and CSF by LC–MS/MS. A two-step compartmental pharmacokinetic analysis was c…

Evidence of a specialized transport mechanism for the intestinal absorption of baclofen

1989

Absorption of the spasmolytic drug baclofen in three selected intestinal segments of living anaesthetized rats in situ, is shown to be a specialized transport mechanism obeying Michaelis-Menten kinetics. Equation parameters were calculated through different procedures, whose features are discussed. A computer method based on the integrated form of Michaelis-Menten equation which reproduces the entire time course of drug absorption from the data found in three intestinal perfusion series at different initial concentrations, yielded Vm and Km values of 12.0 mg h-1 and 8.0 mg, respectively, in the mean segment of the small intestine, a rather selective absorption site for baclofen. Lesser but …

Interaction of Taurine on Baclofen Intestinal Absorption: A Nonlinear Mathematical Treatment using Differential Equations to Describe Kinetic Inhibit…

1996

Previous studies showed that the in situ absorption of baclofen in rat jejunum was inhibited by beta-alanine, a nonessential amino acid, and therefore mediated, at least in part, by some beta-amino acid carrier. In this paper a similar study was undertaken using taurine, a sulfonic beta-amino acid, in order to evaluate its effect and to establish a general inhibition model. To achieve this goal, remaining concentrations of inhibitor were also measured and incorporated into the model. Previously, kinetic absorption in situ parameters for taurine in free solution were obtained: Vm = 27.73 +/- 9.99 mM h-1, K(m) = 8.06 +/- 2.82 mM, Ka (passive difussion component) = 0.40 +/- 0.28 h-1. Isotonic …