Effects of Rocuronium and Vecuronium on Initial Rundown of Endplate Potentials in the Isolated Phrenic Nerve Diaphragm Preparation of Rats.

Effects of rocuronium and vecuronium on initial rundown of endplate potentials in the isolated phrenic nerve diaphragm preparation of rats.

Springerplus. 2013 Dec; 2(1): 155
Li J, Liu YQ, Zhang HT

Rocuronium and vecuronium, two non-depolarizing neuromuscular blockers, have been widely used in surgery procedures. However, their electrophysiological properties need to be more widely explored. We examined the effects of rocuronium and vecuronium on initial rundown of endplate potential amplitudes in the non-uniform stretched muscle preparation of the rat isolated phrenic nerve diaphragm. More specifically, the endplate potentials were recorded with one microelectrode from a single endplate. The effects of rocuronium or vecuronium each at 4 concentrations (0.5 ×, l ×, 2 ×, 4 × EC95; EC95 = concentration of the drug required to produce the inhibitory effect by 95%) on the amplitude of endplate potentials and its rundown were observed. Treatment of the isolated rat phrenic nerve-diaphragm preparation with rocuronium (2.5-20 ?g/ml) or vecuronium (0.5-4 ?g/ml) decreased the amplitude of endplate potentials and inhibited its rundown in a concentration-dependent manner. At the concentration (2.5 ?g/ml for rocuronium and 0.5 ?g/ml for vecuronium) that did not alter the endplate potential amplitude, the onset of reduced endplate potential rundown was 3 and 5 min after administration of rocuronium or vecuronium, respectively. The results suggest that rocuronium and vecuronium block the neuromuscular junction presynaptically and that rocuronium does it faster than vecuronium. HubMed – drug


Assessment of Random Recruitment Assumption in Respondent-Driven Sampling in Egocentric Network Data.

Soc Netw. 2012 Oct 16; 1(2): 13-21
Liu H, Li J, Ha T, Li J

One of the key assumptions in respondent-driven sampling (RDS) analysis, called “random selection assumption,” is that respondents randomly recruit their peers from their personal networks. The objective of this study was to verify this assumption in the empirical data of egocentric networks.We conducted an egocentric network study among young drug users in China, in which RDS was used to recruit this hard-to-reach population. If the random recruitment assumption holds, the RDS-estimated population proportions should be similar to the actual population proportions. Following this logic, we first calculated the population proportions of five visible variables (gender, age, education, marital status, and drug use mode) among the total drug-use alters from which the RDS sample was drawn, and then estimated the RDS-adjusted population proportions and their 95% confidence intervals in the RDS sample. Theoretically, if the random recruitment assumption holds, the 95% confidence intervals estimated in the RDS sample should include the population proportions calculated in the total drug-use alters.The evaluation of the RDS sample indicated its success in reaching the convergence of RDS compositions and including a broad cross-section of the hidden population. Findings demonstrate that the random selection assumption holds for three group traits, but not for two others. Specifically, egos randomly recruited subjects in different age groups, marital status, or drug use modes from their network alters, but not in gender and education levels.This study demonstrates the occurrence of non-random recruitment, indicating that the recruitment of subjects in this RDS study was not completely at random. Future studies are needed to assess the extent to which the population proportion estimates can be biased when the violation of the assumption occurs in some group traits in RDS samples. HubMed – drug


From ?4?2 Nicotinic Ligands to the Discovery of ?1 Receptor Ligands: Pharmacophore Analysis and Rational Design.

ACS Med Chem Lett. 2012 Dec 13; 3(12): 1054-1058
Yu LF, Zhang HK, Gunosewoyo H, Kozikowski AP

Comparative analyses of the pharmacophoric elements required for ?1 and nicotinic ligands led to the identification of a potent and selective ?1 ligand (15). Compound 15 displayed high selectivity for the ?1 receptor (K i, ?1 = 4.1 nM, K i, ?2 = 1312 nM) with moderate binding affinity for the DAT (K i = 373 nM) and NET (K i = 203 nM) in the PDSP broad screening panel of common CNS neurotransmitter transporters and receptors. The key finding in this present work is that a subtle structural modifica tion could be used as a tool to switch a ligand’s selectivity between nAChRs and sigma receptors. HubMed – drug


The totally drug resistant tuberculosis (TDR-TB).

Int J Clin Exp Med. 2013; 6(4): 307-9
Velayati AA, Farnia P, Masjedi MR

HubMed – drug