Effect of propofol and etomidate on normoxic and chronically hypoxic pulmonary artery

BACKGROUND: Chronic alveolar hypoxia results in sustained arterial constriction, and increase in pulmonary vascular resistance leading to pulmonary artery hypertension (PAHT). The aim of this study was to investigate the effect of propofol and etomidate on pulmonary artery (PA) reactivity in chronically hypoxic (CH) rats, a model of pulmonary arterial hypertension (PAHT), in normoxic animals, and human PA. METHODS: CH rats were maintained 14 days at 380 mmHg pressure in a hypobaric chamber. Human tissue was retrieved from histological lung pieces from patients undergoing resection for carcinoma. Cumulative concentrations of anaesthetics were tested on isolated vascular rings precontracted with phenylephrine (PHE) or 100 mM KCl. Statistical comparisons were done by ANOVA, followed, when needed, by Student t tests with Bonferroni correction as post-hoc tests. RESULTS: In normoxic rat PA, maximal relaxation (R(max)) induced by etomidate and propofol was 101.3 ± 0.8% and 94.0 ± 2.3%, respectively, in KCl-precontracted rings, and 63.3 ± 9.7% and 46.1 ± 9.1%, respectively, in PHE-precontracted rings (n = 7). In KCl-precontracted human PA, R(max )was 84.7 ± 8.6 % and 66.5 ± 11.8%, for etomidate and propofol, respectively, and 154.2 ± 22.4 % and 51.6 ± 15.1 %, respectively, in PHE-precontracted human PA (n = 7). In CH rat PA, the relaxant effect of both anaesthetics was increased in PHE-precontracted and, for etomidate only, in KCl-precontracted PA. In aorta, CH induced no change in the relaxant effect of anaesthetics. CONCLUSION: Propofol and etomidate have relaxant properties in PA from human and normoxic rat. The relaxant effect is specifically accentuated in PA from CH rat, mainly via an effect on the pharmacomechanical coupling. Etomidate appears to be more efficient than propofol at identical concentration, but, taking into account clinical concentrations, etomidate is less potent than propofol, which effect was in the range of clinical doses. Although these findings provide experimental support for the preferential use of etomidate for haemodynamic stability in patients suffering from PAHT, the clinical relevance of the observations requires further investigation

THIOPENTONE AND ETOMIDATE CONCENTRATIONS IN MATERNAL AND UMBILICAL PLASMA, AND IN COLOSTRUM

We have measured concentrations of etomidate and thiopentone in maternal plasma, umbilical venous plasma and colostrum after induction of anaesthesia in 40 patients undergoing Caesarean section. Mean plasma etomidate concentration declined rapidly (1242.0 ng ml-1 at 5 min, 434. 0 ng ml-1 at 15 min, 64.2 ng ml-1 at 30 min, 7.0 ng ml-1 at 60 min and undetectable 2 h after the injection). Mean plasma concentrations of thiopentone declined more slowly (6.09 mug ml-1 at 5 min, 2.64 mug ml-1 at 2 h, 1.35 mug ml-1 at 4 h, 0.86 mug ml-1 at 9h and 0.59 mug ml-1 at 12 h). Mean umbilical venous thiopentone concentration was 4.72 mug ml-1, whereas the thiopentone concentration in the maternal sample at 5 min was 6.09 mug ml-1, giving an umbilical:maternal vein ratio of 1:1.3. Mean umbilical etomidate concentration was 51.7 ng ml-1 and the corresponding maternal vein sample (5 min) was 1242.0 ng ml-1 (P<0.001), giving an umbilical:maternal vein ratio of 1:24. Mean concentrations of thiopentone in colostrum were 1.98 mug ml-1 at 30 min, 0.91 mug ml-1 at 4 h and 0.59 mug ml-1 at 9 h, colostrum:plasma ratios at 4 h and 9h being 0.67 and 0.68, respectively. Mean concentrations of etomidate in colostrum were 79.3 ng ml-1 at 30 min and 16.3 ng ml-1 at 2h, being undetectable at 4 h. The colostrum:plasma etomidate concentration ratio was 1.2 at 30 min. We conclude that, although plasma and colostrum concentrations of thiopentone and etomidate declined rapidly, the decrease was faster with etomidate

Synthesis and characterization of Ni(II) and Cd(II) complexes of 4-(4-nitrophenylazo)- 1H-pyrazole-3,5-diamine and 4-(4-methylphenylazo)-1H- pyrazole-3,5-diamine

In this study, the diazotized p-nitroaniline and p-methylaniline were coupled with malononitrile. The ring closure reaction of the obtained products with hydrazine monohydrate yielded 4-(4-methylphenylazo)-1H-pyrazole-3,5-diamine (L1) and 4-(4-nitrophenylazo)-1H-pyrazole- 3,5-diamine (L 2). The structure of the ligands has been elucidated by spectroscopic analyses. Then, novel Ni(II) and Cd(II) complexes of the ligands have been synthesized and the structures of these complexes determined by elemental analysis, spectrometric and TGA/DTA methods, molar conductance and magnetic susceptibility measurements. All the complexes were monomeric and diamagnetic. From the elemental analyses and mass spectra data, the complexes were proposed to the formulae [Ni2(L1)2(OH) 2]·2Cl·8.5H2O, [Cd2(L 1)2(OH)2]·2Cl·DMF·3H2O, [Ni(L2)2]·2Cl·2DMF·7H2O and [Cd2(L2)2(OH)2(H 2O)4]·2Cl·1.5H2O. For the Cd(L2) complex octahedral geometry was proposed, but the Ni(L 1), Ni(L2) and Cd(L1) complexes show four coordinated structure. The Ni(L1), Cd(L1) and Cd(L 2) complexes were found to be dinuclear. On the other hand the Ni(L2) complex was found to be mononuclear. All the complexes were found to be (1:2) electrolytes

Synthesis and Characterization of Novel Mn(II), Co(III), Ni(II) and Cd(II) Complexes from 4-(2-Ntrophenylazo)-1H-Pyrazole-3,5-Diamine

In this study, the diazotized o-nitroaniline was coupled with malononitrile. The ring closure reaction of the obtained product with hydrazine monohydrate yielded 4-(2-nitrophenylazo)-1H-pyrazole-3,5-diamine (L). The structure of L has been elucidated by spectroscopic analyses. Then, novel Mn(II), Co(II), Ni(II) and Cd(II) complexes of L have been synthesized, and the structures of these complexes determined by elemental analysis, spectrometric and TGA/DTA methods, molar conductance and magnetic susceptibility measurements. All complexes were monomeric. Except Mn(II) complex, other complexes were diamagnetic. From the elemental analyses and mass spectra data, the complexes were proposed to the formulas [MnL 2(CH 3O)H 2O]·Cl ·CH 3OH, [CoL 2(CH 3O) 2] ·Cl·2.5CH 3OH, [NiL 2(CH 3OH) 2] ·6.5CH 3OH and [Cd 2L 2(Cl) 2(CH 3O) 2] ·CH 3OH·1.5H 2O. For Mn(II) and Co(III) complexes octahedral and for the Ni(II) complex square planar geometry were proposed, but the Cd(II) complex includes five coordinated structure. The Mn(II), Co(II) and Ni(II) complexes were found to be mononuclear and electrolytes. On the other hand Cd(II) complex was found to be dinuclear and non-electrolyte. © 2011 American Scientific Publishers

High-throughput sorting and analysis of human sperm with a ring-shaped laser trap.

Sperm motility is an important concept in fertility research. To this end, single spot laser tweezers have been used to quantitatively analyze the motility of individual sperm. However, this method is limited with throughput (single sperm per spot), lacks the ability of in-situ sorting based on motility and chemotaxis, requires high laser power (hundreds of milliWatts) and can not be used to dynamically monitor changes in sperm swimming behavior under the influence of a laser beam. Here, we report a continuous 3-D ring-shaped laser trap which could be used for multi-level and high-throughput (tens to hundred sperm per ring) sperm sorting based on their motility and chemotaxis. Under a laser power of only tens of milliWatts, human sperm with low to medium velocity are slowed down, stopped, or forced to change their trajectories to swim along the ring due to the optical gradient force in the radial direction. This is the first demonstration of parallel sperm sorting based on motility with optical trapping technology. In addition, by making the sperm swimming along the circumference of the ring, the effect of laser radiation, optical force and external obstacles on sperm energetics are investigated in a more gentle and quantitative way. The application of this method could be extended to motility and bio-tropism studies of other self-propelled cells, such as algae and bacteria