Search results for "PLASMA"

Relationships betweenin vitrodrug dissolution andin vivoresponse

2012

In recent years there has been an effort to relate manufacturing variables to the performance of the dosage form from a clinical point of view (in terms of safety and efficacy). Consequently any control strategy or the establishment of meaningful specifications should take into consideration the clinical impact on the patient. Since plasma levels are considered to be one of the most useful surrogates for clinical safety (in that bioequivalent plasma levels are considered therapeutically equivalent) and dissolution is the best surrogate for bioavailability, it is a natural consequence that dissolution be used to establish the design space in which all the formulations would have similar safe…

Efecto de la administración concomitante de indometacina o ibuprofeno en la farmacocinética de amikacina en neonatos prematuros

2006

Objective: To evaluate whether the concomitant administration of ibuprofen or indomethacin plus amikacin may alter the latter drug's pharmacokinetic parameters, and hence amikacin plasma levels. Method: Retrospective cohort study performed by reviewing the medical records of premature children with persistent ductus arteriosus receiving amikacin and ibuprofen, or amikacin and indomethacin. They were divided up into three groups: group 1: treatment with amikacin went before indomethacin or ibuprofen; group 2: simultaneously treated with amikacin and indomethacin; group 3: simultaneously treated with amikacin and ibuprofen. Pharmacokinetic parameters, distribution volume, and amikacin clearan…

Modifications induced in the renin-angiotensin-aldo-sterone system of rats by alpha-blocking drugs.

1978

Summary The data reported in the present paper refer to quantitative variations of plasma renin activity and plasma aldosterone levels after administration of alpha-blocking agents, i.e. phentolamine, phenoxybenzamine and gihydroergotoxin derivatives, either to rats kept on a standard diet with water ad libitum or to rats receiving distilled water load, the latter treatment causing an increase of both plasma renin activity and plasma aldosterone levels if compared to control values. No strict correlation between (a) drug-induced modifications of plasma renin activity and plasma aldosterone levels and (b) blood pressure drop caused by the same drugs was shown to occur under either experiment…

Rewarding Properties of Testosterone in Intact Male Mice

2000

The present study examined the rewarding properties of 4-androsten-17β-ol-3-one testosterone in intact male mice using the conditioned place preference (CPP) technique. In Experiment 1, the pharmacokinetics of 0.8 and 1.2 mg/kg of testosterone were studied to determine the most appropriate temporal interval to test behavior. Additionally, the locomotor activity was recorded to control a possible interfering effect on CPP. The maximum testosterone concentration was registered at 45 min of administration, and no effects on activity were found. In Experiment 2, three groups of male OF-1 mice received four pairings of the least-preferred compartment with testosterone (0.8, 1, or 1.2 mg/kg, SC) …

Formation of N-methylnicotinamide in the brain from a dihydropyridine-type prodrug

1999

The enhancement of brain choline levels is a possible therapeutic option in neurodegenerative diseases; however, brain choline levels are held within narrow limits by homeostatic mechanisms including the rapid clearance of excess choline from the brain. The present study tests whether N-methylnicotinamide (NMN), an inhibitor of the outward transport of choline from the brain, can elevate brain choline levels in vivo. As NMN does not cross the blood-brain barrier, we synthesized and administered the brain-permeable prodrug, 1,4-dihydro-N-methyl-nicotinamide (DNMN), and tested its effect on the levels of NMN and choline in brain extracellular fluid, using the microdialysis procedure. Administ…

Variations of plas14a benin activity and aldostehone levels in the rat after administration of saline, chrystalloid and colloid solutions

1976

Abstract The data reported in the present paper refer to quantitative variations of plasma renin activity (PRA.) and of plasma aldosterone levels in rats after adiministration of saline, chrystalloid and colloid solutions. In our experimental conditions PRA and plasma aldosterone levels were shown to increase significantly after administration of distilled water and glucose solution. Variations of PRA and plasma aldosterone levels were only slight when plasma volume was made to increase due to administration of polyvinylpirrolidone solution. PRA, instead, was significantly lower in rats having received saline salution.

Active locking and entanglement in type II optical parametric oscillators

2018

Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase-difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entangl…

From capillary condensation to interface localization transitions in colloid-polymer mixtures confined in thin-film geometry.

2008

Monte Carlo simulations of the Asakura-Oosawa (AO) model for colloid-polymer mixtures confined between two parallel repulsive structureless walls are presented and analyzed in the light of current theories on capillary condensation and interface localization transitions. Choosing a polymer to colloid size ratio of q=0.8 and studying ultrathin films in the range of D=3 to D=10 colloid diameters thickness, grand canonical Monte Carlo methods are used; phase transitions are analyzed via finite size scaling, as in previous work on bulk systems and under confinement between identical types of walls. Unlike the latter work, inequivalent walls are used here: while the left wall has a hard-core rep…

No Label Required: Protein Binding at Membrane Interfaces Visualized through Colloid Phase Transitions

2004

Neutron star collapse and gravitational waves with a non-convex equation of state

2018

The thermodynamical properties of the equation of state (EoS) of high-density matter (above nuclear saturation density) and the possible existence of exotic states such as phase transitions from nuclear/hadronic matter into quark-gluon plasma, or the appearance of hyperons, may critically influence the stability and dynamics of compact relativistic stars. From a theoretical point of view, establishing the existence of those states requires the analysis of the `convexity' of the EoS. We show indications of the existence of regions in the dense-matter EoS where the thermodynamics may be non-convex as a result of a non-monotonic dependence of the sound speed with the rest-mass density. When th…