An <Emphasis Type="Italic">Insilico</Emphasis> approach to High Altitude Pulmonary Edema - Molecular modeling of human β<Subscript>2</Subscript> adrenergic receptor and its interaction with Salmeterol &; Nifedipine

Knowledge of the three-dimensional structures of protein targets from genomic data has the potential to accelerate researches pertaining to drug discovery. Human β₂ adrenergic receptor is a G-protein-coupled receptor with seven transmembrane helices, and is important in pharmaceutical targeting on pulmonary and cardiovascular diseases. The human β₂ adrenergic receptor has been found to play a very important role in the pathogenesis of high altitude pulmonary edema (HAPE). In the present study, a high quality of protein 3D structure has been predicted for the human β₂ adrenergic receptor sequence with primary accession number P07550. Homologous template protein sequence with known 3D structure was identified and the template-query protein sequence validation was done by multiple sequence alignment method. The homology model was performed through Modeller and depended on the quality of the sequence alignment by BLAST, template structure and the consolidated result performed by Gene silico meta-server. The statistical verification of the generated model was evaluated by PROCHECK which revealed that the structure modeled through Modeller to be of good quality with 84.1% of residues in the most favored region. Docking studies were carried out after modeling with two well known ligands namely Salmeterol and Nifedipine, and the fitness score revealed that Salmeterol has a higher fitness score than Nifedipine. Estimation of binding affinity by X-Score revealed that Salmeterol had −10.40 binding affinity while Nifedipine showed −9.62 binding affinity. From the present study, it can be concluded that the generated model of human β₂ adrenergic receptor can be used for further studies related to this receptor and Salmeterol was found to have a high binding affinity with human β₂ adrenergic receptor.     

Involvement of voltage-gated K+ and Na+ channels in gastric epithelial cell migration

Epithelial cell migration plays an important role in gastrointestinal mucosal repair. We previously reported that multiple functional ion channels, including a Ba²⁺-sensitive K⁺ inward rectifier K_ir1.2, 4-aminopyridine (4-AP)-sensitive voltage-gated K⁺ channels K_v1.1, K_v1.6 and K_v2.1, and a nifedipine-sensitive, tetrodotoxin (TTX)-insensitive voltage-gated Na⁺ channel Na_v1.5 were expressed in a non-transformed rat gastric epithelial cell line (RGM-1). In the present study, we further investigated whether these ion channels are involved in the modulation of gastric epithelial cell migration. Cell migration was determined by monolayer wound healing assay. Results showed that blockade of K_v with 4-AP or Na_v1.5 with nifedipine inhibited RGM-1 cell migration in the absence or presence of epidermal growth factor (EGF), which effectively stimulated RGM-1 cell migration. Moreover, high concentration of TTX mimicked the action of nifedipine, suggesting that the action of nifedipine was mediated through specific blockade of Na_v1.5. In contrast, inhibition of K_ir1.2 with Ba²⁺, either in basal or EGF-stimulated condition, had no effect on RGM-1 cell migration. In conclusion, the present study demonstrates for the first time that voltage-gated K⁺ and Na⁺ channels are involved in the modulation of gastric epithelial cell migration.     

A calcium channel blocker nifedipine distorts the effects of nano-zinc oxide on metal metabolism in the marsh frog Pelophylax ridibundus

Global decline of amphibian populations causes particular concern about their vulnerability to novel environmental pollutants, including engineering nanomaterials and pharmaceutical products. We evaluated the bioavailability of nanoform of zinc oxide (n-ZnO) in frog Pelophylax ridibundus and determined whether co-exposure to a common pharmaceutical, a calcium-channel blocker nifedipine (Nfd) can affect this bioavailability. Male frogs were exposed for 14 days to the tap water (Control) and n-ZnO (3.1 μM), Zn²⁺ (3.1 μM, as a positive control for n-ZnO exposures), Nfd (10 μM), and combination of n-ZnO and Nfd (n-ZnO + Nfd) in environmentally-relevant concentration. Exposure to Zn²⁺ or n-ZnO led to up-regulation of metal-binding proteins, metallothioneins (MTs) in the liver and Zn-carrying vitellogenin-like proteins in the blood plasma. Notably, upregulation of MTs by Zn²⁺ or n-ZnO exposures combined with increased binding of Zn and Cu to MTs. This was associated with the more reducing conditions in the liver tissue indicated by elevated lactate to pyruvate ratio. Nfd suppressed the binding of Zn and Cu to MTs and led to a decrease in Lactate/Pyruvate ratio and elevated protein carbonylation indicating pro-oxidant conditions. Redox status parameters were not directly related to DNA fragmentation, nuclear abnormalities or suppression of cholinesterase activity indicating that factors other than oxidative stress are involved in cytotoxicity of different pollutants and their combinations. Furthermore, activity of Phase I biotransformation enzyme (CYP450 oxidase measured as EROD) was elevated in Nfd-containing exposures and in Zn²⁺ exposed frogs. Tyrosinase-like activity in the frog liver was strongly stimulated by Zn²⁺ but suppressed by n-ZnO, Nfd and n-ZnO + Nfd. These findings show that Nfd modulates homeostasis of essential metals in amphibians and emphasize that physiological consequences of combined n-ZnO and Nfd exposures are difficult to predict based on the mechanisms of single stressors.     

Effect of polyamidoamine (PAMAM) dendrimers on the in vitro release of water-insoluble nifedipine from aqueous gels

The objective of this study was to determine the effect of ethylenediamine core PAMAM dendrimers, on the release of nifedipine suspended in aqueous gels and to correlate release to the increase in solubility afforded by the dendrimers. Drug release from aqueous 5% HPMC gels containing nifedipine (2% wt/vol) through 0.2-μm membranes was measured using Enhancer cells and 50% ethanolic solution as the receptor medium. The release from gels containing PAMAM G-3 and G-5 (0.25%–1% wt/vol) was compared with gels containing the cosolvent isopropyl alcohol (10%–80% vol/vol). PAMAM dendrimers significantly increased the solubility of nifedipine. This caused a significant increase in the release rate of nifedipine from the gel suspensions. The increase in drug release depended on the concentration and generation size of the dendrimers added. For higher generations (G-5) lower concentrations were needed to obtain equivalent increases in release. Although the increase in solubility and release was not as high as from gels containing high concentrations of the cosolvent isopropyl alcohol, the dendrimers prevented the recrystallization of the drug that was observed when the gels containing isopropyl alcohol were left open. Published: October 24, 2005     

卡托普利与心痛定治疗高血压急症的疗效观察

目的以卡托普利舌下含服治疗高血压急症,并与心痛定舌下含服治疗对照。方法卡托普利２５ｍｇ舌下含服治疗高血压急症６０例为治疗组,６０例用心痛定１０ｍｇ舌下含服作对照组。结果卡托普利组用药１５ｍｉｎ即开始有显著的降压作用（Ｐ＜０．００１）,３０ｍｉｎ、６０ｍｉｎ、１２０ｍｉｎ后疗效更显著（Ｐ＜０．００１）。心痛定组用药１５ｍｉｎ血压无显著下降（Ｐ＞０．０５）。３０ｍｉｎ、６０ｍｉｎ、１２０ｍｉｎ,血压明显下降（Ｐ＜０．００１）,两组比较,卡托普利组降压作用明显（Ｐ＜０．００１）。结论卡托普利舌下含服是治疗高血压急症较迅速、有效、安全的降压方法,无明显不良反应。     

Effects of light/dark and calcium-channel drugs on fluxes of 86Rb+ in “isolated” guard cells of Vicia faba L.

Experiments on ⁸⁶Rb⁺ fluxes were used to identify the changes in ionic state induced by transferring stomata from light to darkness. Guard-cell fluxes and contents were measured on isolated epidermal strips from Vicia faba L. in which all cells other than the guard cells had been killed by ultrasonic disruption. Closure of stomata in response to darkness was achieved by a large, transient stimulation of ⁸⁶Rb⁺ efflux from the guard cells, combined with a reduction of ion transfer from cytoplasm to vacuole, but there was little significant change in influx. Removal of blue but not red light appeared to trigger the flux responses associated with darkening. Attempts to inhibit the closing response (using methoxyverapamil, nifedipine and bepridil, compounds possessing activity against the calcium channels of animal cells) were mostly unsuccessful and the significance of this result is discussed.Abbreviations and Symbols A amplitude - K rate constant - Mes 2-(N-morpholino)ethanesulfonic acid - Q ^* tracer content - s specific activity - R rate of trace loss - Q _T, Q _C, Q _V total, cytoplasmic and vacuolar contents - flux This work was supported by a Research Studentship from the Science and Engineering Research Council. I thank Professor E.A.C. MacRobbie for much helpful discussion and advice.     

Calcium influx at the plasmalemma of Chara corallina

Influx of ⁴⁵Ca into internodal cells of Chara corallina has been measured, using short uptake times, and a wash in ice-cold La³⁺-containing pondwater after the labelling period to overcome the difficulty of distinguishing extracellular tracer from that in the cell. Over 5–15 min the uptake was linear with time, through the origin. The basal influx from 0.1 mM Ca²⁺ externally was 0.25–0.5 pmol·cm^-2·s^-1, but some batches of cells showed higher fluxes. The influx was markedly stimulated by depolarisation in pondwater containing 20 mM K⁺. In cells in which the control flux was less than about 0.5 pmol·cm^-2·s^-1 there was no effect of 50 M nifedipine. In cells in which the control flux was greater than about 0.5 pmol·cm^-2·s^-1 (whether by natural variability, pretreatment, or by depolarisation in 20 mM K⁺), the flux was reduced by 50 M nifedipine to a value in the range 0.25–0.59 pmol·cm^-2·s^-1. It is suggested that two types of Ca-channel are probably involved, both opening on depolarisation, but only one sensitive to nifedipine. The flux was inhibited by 10 M BAY K 8644, which in animal cells more commonly opens Ca-channels. The apparent influx measured over long uptake times was much reduced, and the kinetics indicated filling a pool of apparent size about 1.45 nmol·cm^-2 with a halftime of about 38 min, probably representing cytoplasmic stores. It is argued that in spite of the very small pool of (free+bound) cytoplasmic Ca²⁺ the measured influx is a reasonable estimate of the influx at the plasmalemma.Abbreviations 0.4K-APW6 artificial pondwater, pH 6, containing 0.4 mM KCl - 20 K-APW6 artificial pondwater, pH 6, containing 20 mM KCl - Ca_o external Ca²⁺     

硝苯地平与硫酸镁治疗妊娠高血压综合征的临床疗效及对患者血清肌 酐、HSP70 及尿微量白蛋白水平的影响

目的:探讨硝苯地平联合硫酸镁对妊娠高血压综合征患者血清肌酐、HSP70及尿微量白蛋白水平的影响。方法:选取近5年在我院接受治疗的妊娠高血压综合征患者60例,随机分为实验组和对照组,每组30例。对照组患者采用硫酸镁治疗,实验组患者采取硝苯地平联合硫酸镁治疗。观察并比较治疗前后两组患者血清肌酐(Scr)、血尿素氮(BUN)、血尿酸(UA)热休克蛋白70(HSP70)及24 h尿微量白蛋白水平以及收缩压及舒张压的变化。结果:与治疗前相比,两组患者Scr、BUN、UA、HSP70及24 h尿微量白蛋白水平和收缩压及舒张压均显著降低(P0.05);与对照组相比,实验组患者上述指标均明显降低(P0.05)。结论:硝苯地平联合硫酸镁能够降低妊娠高血压综合征患者血压,保护患者肾功能。     

Nifedipine loaded chitosan microspheres: characterization of internal structure

In the present investigation, a simple technique was employed to obtain cross-sections of unloaded and nifedipine loaded chitosan microspheres. Microspheres, adhering to a polymerized resin block, were cut with an ultramicrotome and viewed with a scanning electron microscope. Unloaded microspheres exhibited a uniform dense matrix structure while crystals of nifedipine were clearly visible in the drug-loaded microspheres. At 2% drug loading, however, no crystals could be seen in the microspheres indicating that either the drug was molecularly dispersed or dissolved in the matrix at this concentration. This was confirmed by powder X-ray diffractometry studies where no peak due to crystalline nifedipine was observed. At high Span 85 concentration (1.5% w/v), the external surface of the microspheres collapsed, but the internal structure remained dense. When the drug was dispersed in the chitosan solution with stirring during preparation, the entrapment was good and the shape of the crystals was changed. The internal structure of the microspheres following dissolution exhibited the presence of pores.     

硫酸镁联合硝苯地平治疗中重度妊娠高血压综合征患者的疗效观察

目的:探讨硫酸镁联合硝苯地平治疗中重度妊娠期高血压综合征的临床疗效。方法:选取2013年5月-2014年10月我院收治的中重度妊娠期高血压综合征患者70例,随机将患者分为研究组和对照组,每组35例。对照组患者应用硫酸镁治疗,研究组患者给予硫酸镁联合硝苯地平治疗,比较两组患者的临床疗效、血压变化、血液粘度、24 h尿蛋白含量以及血细胞压积情况。结果:研究组治疗总有效率显著优于对照组,差异具有统计学意义(P0.05);两组患者治疗后的血压水平显著低于治疗前,且研究组显著优于对照组,差异具有统计学意义(P0.05);两组患者治疗后的血液粘度、24 h尿蛋白含量及血细胞压积显著优于治疗前,且研究组优于对照组,差异具有统计学意义(P0.05)。结论:硫酸镁联合硝苯地平治疗中重度妊娠期高血压具有较好的临床疗效,能够显著改善患者的临床症状。