Hydrogen sulfide regulates vascular endoplasmic reticulum stress in apolipoprotein E knockout mice

Background  Atherosclerosis is an important cardiovascular disease, becoming a major and increasing health problem in developed countries. However, the possible underlying mechanisms were not completely clear. In 2009, our research group first discovered that hydrogen sulfide (H₂S) as a novel gastrotransmitter played an important anti-atherosclerotic role. The study was designed to examine the regulatory effect of hydrogen sulfide (H₂S) on endoplasmic reticulum stress (ERS) in apolipoprotein E knockout (apoE^-/-) mice fed a Western type diet.

Methods  C57BL/6 mice and homozygous apoE^-/- mice were fed a Western type diet. C57BL/6 mice were injected intraperitoneally with normal saline (5 ml/kg per day) as control group. The apoE^-/- mice were treated with the same dose of normal saline as the apoE^-/- group, injected intraperitoneally with sodium hydrosulfide (NaHS, an H₂S donor, 56 μmol/kg per day) as the apoE^-/-+NaHS group and injected intraperitoneally with DL-propargylglycine (PPG, a cystathionine-γ-lyase inhibitor, 50 mg/kg, per day) as the apoE^-/- +PPG group. After 10 weeks, the mice were sacrificed and the plasma lipids were detected. Sections of aortic root from these animals were examined for atherosclerotic lesions by HE and oil red O staining. The aortic ultrastructure and microstructure were analyzed with the help of light and electronic microscope. Glucose-regulated protein 78 (GRP78), caspase-12, copper-andzinc-containing superoxide dismutase (Cu/ZnSOD) and Mn-containing superoxide dismutase (MnSOD) protein expression in aortic tissues were detected with immunohistochemistry. The level of intracellular reactive oxygen species (ROS) were measured by using a commercial assay kit.

Results  Compared with control mice, apoE^-/- mice showed increased plasma levels of total cholesterol (TC), triglyceride (TG) and low density lipoprotein (LDL), decreased high density lipoprotein (HDL), increased aortic plaque size, destroyed ultra-structure of aortic tissue, and increased expression of GRP78 and caspase-12 proteins. Compared with apoE^-/- mice, H₂S donor-treated apoE^-/- mice showed a decreased plasma LDL level, lessened plaque necrosis and attenuated aortic ultra-structural disorder. H₂S donor-treatment induced GRP78 expression but suppressed caspase-12 expression in aortic lesions. However, compared with apoE^-/- mice, PPG treated apoE^-/- mice showed enlarged plaque size, more severe ultrastructural disorder of the aortic tissue and reduced GRP78 staining in aortic lesions. The plasma lipids and the staining of caspase-12 in apoE^-/- + PPG rats did not significantly differ from those in the apoE^-/-mice. Consistently, H₂S induced SOD expression, accompanied by a reduced level of ROS.

Conclusion  H₂S plays a regulatory role in aortic ERS and reduces atherosclerotic lesions in apoE^-/- mice fed with a Western type diet.

     

80例正常人体表标测Q-Tdp的观察

采用91导联体表电位标测法(BSPM)观察80例正常人Q-T_d^p(Q波起点到T波峰值间期的离散度),与同步12导联心电图Q-T离散度(Q-T_d)对照,探讨BSPM条件下测定Q-T_d的可行性。结果：① Q-T^p、Q-T_d^p、Q-T_c1d^p(Bazzett公式校正)、Q-T_c2d^p(Fridercia公式校正)分别为(292.69±37.75) ms、(36.77±7.40) ms、(40.23±9.04) ms和(40.11±7.73) ms;②Q-T_d^p与Q-T_d、Q-T_c1d^p与Q-T_c1d、Q-T_c2d^p与Q-T_c2d有良好的相关性;③3个年龄组(18～35岁、36～60岁、61～70岁)各参数间无显著性差异;④Q-T^p女性明显大于男性(P<0.05),其余各值男女性之间均无显著性差异。提示：BSPM测定 Q-T_d^p简便可行、较为准确,正常值可暂定为52 ms。     

毛兰素注射液在大鼠体内药动学研究

目的 阐明毛兰素注射液在SD大鼠体内药动学规律。方法 SD大鼠分别单次和隔天、每隔一个半衰期一次多剂量静脉注射毛兰素注射液。采用高效液相色谱-质谱联用(HPLC-MS)测定大鼠静脉注射后不同时间大鼠血浆中毛兰素的血药浓度。结果 大鼠单次静脉注射25,50,100 mg·kg^-1毛兰素注射液的主要药动学参数为：T_1/2β分别为3.66,3.75,3.89 h; AUC_0-12分别为1 453.0,3 041.6,6 731.6 ng·mL^-1·h;AUC_0-∞分别为1 462.0,3 077.3,6 788.7 ng·mL^-1·h;Vd分别为11.67,10.37,3.38 L·kg^-1;CL分别为0.049,0.089,0.024 L·kg^-1·h^-1;MRT分别为0.18,0.28,0.21 h;50 mg·kg^-1剂量的毛兰素注射液隔日给药5次其药动学参数与单次给药相近;而50 mg·kg^-1剂量的毛兰素注射液每隔一个半衰期一次给药5次的T_1/2β为5.43 h,AUC_(S0)(0-t)为9 800.8 ng·mL^-1·h。结论 毛兰素注射液在大鼠体内的动力学过程与剂量相关,毛兰素注射液单剂量给药的体内药动学符合开放型二房室模型,T_1/2β与给药剂量与关,表明毛兰素在大鼠体内的消除过程符合一级动力学规律。隔日多剂量给药的消除过程亦符合一级动力学规律;而每隔一个半衰期一次多剂量给予50 mg·kg^-1剂量的毛兰素其在大鼠体内则呈非线性消除。     

Erythrocytic or serum hydrogen sulfide association with hypertension development in untreated essential hypertension

Background  Endogenous hydrogen sulfide (H₂S) plays an important role in hypertension. The aim of this study was to investigate the role of erythrocyte and serum H₂S in patients with untreated essential hypertension.

Methods  We recruited 62 patients (age 22–74 years) with untreated prehypertension or hypertension, and 64 normotensive subjects (age 18–64 years). We assessed the 3-mercaptopyruvate sulphurtransferase (MPST) protein expression in erythrocytes and measured the H₂S production from erythrocytes and serum H₂S levels, then analyzed the association of erythrocytic or serum H₂S content and blood pressure or cardiovascular risk factors (e.g., age, body mass index (BMI) and dyslipidemia). A stepwise regression analysis was used to evaluate the possible relationship of erythrocytic H₂S in hypertension.

Results  In hypertensive patients, erythrocyte H₂S production ((111.04±29.20) nmol/min per 10⁸ erythrocytes) was higher than that in controls ((78.85±19.38) nmol/min per 10⁸ erythrocytes), and serum H₂S was also higher. The erythrocytic H₂S production was associated with increased systolic blood pressure (sBP), diastolic blood pressure (dBP), age, BMI, level of C-reactive protein (CRP), as well as triglycerides (TG) and high density lipoprotein cholesterol (HDL-C). Serum H₂S was not associated with age or CRP. Stepwise regression analysis showed that erythrocytic H₂S production was correlated with sBP, TG, HDL-C, low density lipoprotein cholesterol (LDL-C) and blood urea nitrogen (BUN) and serum H₂S was correlated with dBP and TG. Results of receiver-operating characteristic curve analysis suggested that erythrocytic H₂S production was a more sensitive predictor of hypertension development than serum H₂S.

Conclusion  Erythrocytic or serum H₂S production is sensitive predictor of hypertension.

     

3, 5, 4'-三甲基白藜芦醇对豚鼠心室肌细胞钠电流和钾电流的影响

目的 研究3, 5, 4''-三甲基白藜芦醇(trans-resveratrol derivative 3,5,4''-trimethoxystilbene，TMS)对豚鼠心室肌细胞钠电流(I_Na)和钾电流(I_K1)的直接作用，探讨其心肌保护作用。方法 用全细胞膜片钳技术记录TMS对单个心室肌细胞I_Na和I_K1的作用。结果 TMS(10 μmol·L^-1)可快速抑制豚鼠心室肌细胞I_Na，用药后3 min左右即开始起效，10 min时抑制率为(36.8±5.6)％(P<0.005)，洗脱后可完全恢复；1，3 μmol·L^-1 TMS未影响I_Na大小。TMS不改变I_Na的最大激活电压，也不影响I_K1的大小。10 μmol·L^-1使半数最大失活电压(V_1/2)由(-87.0±3.3)mV变化到(-96.7±3.5)mV (P<0.001)，使失活曲线斜率(S)由(4.9±0.3)mV 变化到(5.4±0.3)mV (P<0.01)；使半数最大激活电压(V_1/2) (-38.9±1.4)mV 变化到(-47.3±1.3)mV (P<0.001)，未改变激活S。结论 TMS可直接作用于豚鼠心室肌细胞，快速抑制I_Na，且此作用快速、可逆。     

HPLC–MS/MS测定赖诺普利血药浓度及其在药动学研究中的应用

目的 建立HPLC-MS/MS测定人血浆中赖诺普利的浓度并研究其药动学特征,为该药的临床应用提供依据。方法 20名健康受试者单剂量口服赖诺普利片20 mg后,采用HPLC-MS/MS测定其血药浓度,利用DAS软件对血药浓度-时间数据进行药动学模型拟合和参数计算,应用AIC法判别房室模型。结果 血浆中赖诺普利在2.0~200 ng·mL^-1内线性关系良好(r=0.997 5),平均回收率为88.8%,日内RSD≤6.62%,日间RSD≤13.0%。最佳房室模型为单室模型(Wi=1/C2, AIC=4.61),主要药动学参数t_1/2为(10.91±3.71)h,t_max为(6.65±1.50)h,C_max为(98.15±23.66)ng·mL^-1,Ka为(0.83±1.28)h^-1,Vd/F为(220.70±62.82)L,AUC_0-72为(1 437.41±399.68)ng·h·mL^-1,AUC_0-∞为(1 516.54±376.83)ng·h·mL^-1。结论 该分析方法专属性强、灵敏度高,适合大样本分析,满足临床血药浓度监测的要求并适用于药动学领域的研究。     

Electrophysiological effects of hydrogen sulfide on human atrial fibers

Background  It has been reported that endogenous or exogenous hydrogen sulfide (H₂S) exerts physiological effects in the vertebrate cardiovascular system. We have also demonstrated that H₂S acts as an important regulator of electrophysiological properties in guinea pig papillary muscles and on pacemaker cells in sinoatrial nodes of rabbits. This study was to observe the electrophysiological effects of H₂S on human atrial fibers.

Methods  Human atrial samples were collected during cardiac surgery. Parameters of action potential in human atrial specialized fibers were recorded using a standard intracellular microelectrode technique.

Results  NaHS (H₂S donor) (50, 100 and 200 μmol/L) decreased the amplitude of action potential (APA), maximal rate of depolarization (V_max), velocity of diastolic (phase 4) depolarization (VDD) and rate of pacemaker firing (RPF), and shortened the duration of 90% repolarization (APD₉₀) in a concentration-dependent manner. ATP-sensitive K⁺ (K_ATP) channel blocker glibenclamide (Gli, 20 μmol/L) partially blocked the effects of NaHS (100 μmol/L) on human atrial fiber cells. The L-type Ca²⁺ channel agonist Bay K8644 (0.5 μmol/L) also partially blocked the effects of NaHS (100 μmol/L). An inhibitor of cystathionine γ-lyase (CSE), DL-propargylglycine (PPG, 200 μmol/L), increased APA, V_max, VDD and RPF, and prolonged APD₉₀.

Conclusions  H₂S exerts a negative chronotropic action and accelerates the repolarization of human atrial specialized fibers, possibly as a result of increases in potassium efflux through the opening of K_ATP channels and a concomitant decrease in calcium influx. Endogenous H₂S may be generated by CSE and act as an important regulator of electrophysiological properties in human atrial fibers.

     

HPLC荧光法测定高三尖杉酯碱在大鼠体内的分布

目的 研究高三尖杉酯碱注射液在大鼠体内的组织分布,为该药进行临床研究及合理应用提供依据。方法 生物样品在碱性条件下通过氯仿提取,用Kromasil C₁₈柱(4.6 mm×150 mm,5 μm),乙腈-10 mmol·L^-1 KH₂PO₄缓冲液(含0.2%三乙胺,用H₃PO₄调pH至2.5)(25∶75)为流动相,荧光检测波长为λex 280 nm,λem 320 nm。结果 绝对回收率为91.27%~102.4%,最低检测限为0.5 ng·mL^-1。SD大鼠单次尾静脉注射高三尖杉酯碱注射液0.5,1,2 h后主要效应器官的浓度分布特点是：C_骨髓>C_心,主要消除器官的浓度分布特点是C_肝>C_肺>C_肾。结论 本法准确,灵敏度高,可用于高三尖杉酯碱的体内过程研究。高三尖杉酯碱在骨髓中有较高浓度分布,应引起重视。     

Ocular higher-order aberrations features analysis after corneal refractive surgery

Background  The recent studies have shown that visual performance might be affected by the ocular aberration after the corneal refractive surgery, and try to minimize it. This study was to investigate the effects of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) on the higher order of wavefront aberration and analysis of their characteristics.
Method  This prospective study involved 32 eyes with similar refractive powers (-5.0 D to -6.0 D preoperatively). LASIK and PRK were performed with the same parameters of 6 mm diameter optical zone and 7 mm diameter transition zone ablation. Wavefront aberrations were tested using a ray tracing technique preoperatively and 3 months postoperatively. Three measurements were obtained for each condition; the root mean squared wavefront error (RMS), values for overall wavefront aberrations and each order of the Zernike aberrations were analyzed using the Matlab software. The 2-tailed t test was used for statistical analysis.
Results  Overall higher order aberrations were increased from (0.550.26) µm preoperatively to (0.930.37) µm for PRK and (0.790.38) µm for LASIK postoperatively. This was a 1.69 fold increase in the PRK group (t=3.95, P<0.001) and a 1.43 fold increase in the LASIK group (t=2.60, P<0.05). At 3 months, the mean RMS value for higher-order (3rd to 6th) were significantly increased compared with the corresponding preoperative values (P<0.05). The fourth order aberrations, spherical like aberration, were dominant by a 2.64 fold in PRK and a 2.31 fold in LASIK. Different influences of the PRK group and LASIK group were shown in the various zernike components. The statistically significant differences were seen in C₄⁰, C₄⁺⁴, C₅⁺¹, C₅⁺³, C₅⁺⁵ and C₆⁺² of the PRK group and C₃^-3, C₄⁰, C₅^-5, C₅⁺⁵, C₆^-2 of the LASIK group, which represents a 7.42, 3.58, 9.21, 2.72 and 5.3 fold increases in PRK group, and 6.40, 10.80, 11.06, 3.47 and 6.09 fold increases in LASIK group, respectively. C₃^-3 in LASIK was higher and C₅⁺¹ and C₅⁺³ were lower than those in the PRK group. C₄⁰ (spherical aberration) values were similar between PRK and LASIK, however, C₃^-1 and C₃¹ (coma) in LASIK were higher than those in PRK, but these differences are of no statistical significance.
Conclusions  PRK and LASIK may increase ocular higher-order aberrations, but they both have their own features. The difference between the two types of surgery may be correlated with the change of the corneal shape, the conversion of biodynamics, the healing of the corneal cut, and re-structured corneal epithelium and/or the stroma.

     

桂花不同溶剂提取物对氧自由基清除作用的ESR研究

目的 研究桂花不同提取物对氧自由基的清除作用。方法 利用不同极性溶剂(水、石油醚、乙酸乙酯、正丁醇)浸提桂花粉后得到不同极性的提取物。通过电子自旋共振(ESR)和自旋捕集技术,以1,1-二苯基-2-三硝基苯肼自由基(DPPH)及核黄素光照条件下产生超氧阴离子O₂^-自由基体系,检测桂花中各组分清除DPPH自由基及O₂^-的能力。结果 以维生素C为对照,桂花水提取物、石油醚提取物、乙酸乙酯提取物、正丁醇提取物及维生素C清除DPPH自由基能力IC₅₀分别为59.63,53.93,28.33,38.89,40.93 μg·mL^-1;各提取物及维生素C对超氧阴离子O₂^-自由基清除能力IC50分别为63.37,55.47,30.20,48.36,41.52 μg·mL^-1。其中各提取物的乙酸乙酯提取物的DPPH及O₂^-清除率最大。结论 通过比较各组分对DPPH自由基及超氧阴离子自由基的清除能力,了解桂花中抗氧化成分在各相中的分布情况,并据此进行有目的的分离桂花中的抗氧化成分。     

HPLC-MS/MS测定人血浆阿奇霉素浓度及生物等效性研究

目的 建立人血浆中阿奇霉素的高效液相色谱/质谱/质谱(HPLC-MS/MS)测定法,测定受试者口服阿奇霉素颗粒后的血药浓度,并对受试制剂与参比制剂的生物等效性进行评价。方法 19名健康受试者采用随机双交叉试验设计,单剂量口服阿奇霉素颗粒受试制剂和参比药物各500 mg,用HPLC-MS/MS测定用药后不同时间血药浓度。血药浓度-时间数据经DAS 2.0统计软件处理,计算主要药动学参数,并进行两种制剂的生物等效性评价。结果 受试制剂和参比制剂的T_max分别为(2.5±1.1)h和(2.6±1.7)h,C_max分别为(574.6±209.2) ng·mL^-1和(594.5±229.9) ng·mL^-1,t_1/2分别为(44.7±15.2) h和(42.0±13.0) h,AUC_0-144分别为(5 319.6±2 507.8) h·ng·mL^-1和(5 710.7±2 710.1)h·ng·mL^-1,AUC^_0-∞分别为(5 704.2±2 858.7) h·ng·mL^-1和(6 010.0±2 808.1) h·ng·mL^-1, 以AUC_0-144计算,相对生物利用度为(94.2±15.7)%。两制剂的主要药动学参数无显著性差异。结论 受试制剂与参比药物生物等效。     

Pharmacokinetic study of single and multiple oral dose administration of antofloxacin hydrochloride in healthy male volunteers

Background  A new fluroquinolone antibacterial agent, antofloxacin hydrochloride, developed in China, is an 8-NH₂ derivant of levofloxacin. The purpose of the study was to evaluate the pharmacokinetic characteristics of single and multiple oral doses of antofloxacin hydrochloride in Chinese healthy male volunteers.

Methods  An open-label, non-randomized, single and multiple dose clinical trial was conducted. In single dose study, 12 subjects took 200 mg antofloxacin hydrochloride. In multiple dose study, 12 subjects took antofloxacin hydrochloride 400 mg once on day 1 and 200 mg once daily from day 2 to day 7. HPLC was used to assay the serum and urinary concentrations of antofloxacin.

Results  In single dose study, the maximum concentration of drug in serum (C_max), the time to reach C_max (T_max), and the area under the serum concentration-time curve (AUC (0-∞)) of antofloxacin were (1.89±0.65) mg/L, (1.29±0.26) hours, and (25.24±7.26) mg∙h^-1∙L^-1, respectively. Accumulating elimination rate of antoflocaxin from urine within 120 hours was 39.1%. In multiple dose study, blood concentration of antofloxiacin achieved stable state on day 2 after dosing. The minimum concentration drug in serum (C_min), AUCss, mean concentration of drug in serum (C_av), and degree of fluctuation (DF) were (0.73±0.18) mg/L, (47.59±7.85) mg∙h^-1∙L^-1, (1.98±0.33) mg/L, and 1.74±0.60, respectively. On day 7 after dosing, T_max, C_max, and AUC (0-∞) was (1.14±0.50) hours, (2.52±0.38) mg/L, and (48.77±8.44) mg∙h^-1∙L^-1, respectively. Accumulating elimination rate of antofloxaxin from urine within 120 hours after the last dosing was 60.06%.

Conclusions  The regimen of 400 mg loading dose given on the first treatment day and then 200 mg dose once daily results in satisfactory serum drug concentration.

     

卡介苗多糖核酸注射液预防过敏性紫癜复发的82例临床观察

目的 观察卡介苗多糖核酸注射液预防过敏性紫癜(HSP)复发的临床效果及相关因素分析。方法　82例HSP患儿随机分为治疗组46例和对照组36例,33例健康儿童作为正常对照组。对照组常规治疗,治疗组加卡介苗多糖核酸注射液肌注,0.5 mg,1周2次,疗程为3个月。观察1年内病情的反复、复发率及测定治疗前、治疗3个月后血CD₃⁺,CD₄⁺,CD₈⁺,白介素-2(IL-2),γ-干扰素(IFN-γ),IgA水平。结果　HSP患儿治疗前血CD₃⁺,CD₄⁺,IL-2,IFN-γ水平均低于正常对照组(P<0.01),IgA明显上升(P<0.01),CD8+细胞水平各组间无明显差异(P>0.05),观察3个月后复查血CD₃⁺,CD₄⁺,CD₈⁺,IL-2,IFN-γ,IgA水平,发现治疗组的各项指标恢复较对照组明显(P<0.05或<0.01),1年复发率明显下降(P<0.05)。结论　卡介苗多糖核酸能调节HSP患儿免疫功能,能有效降低复发率。     

Molecular mechanisms of diabetic coronary dysfunction due to large conductance Ca2+-activated K+ channel impairment

Background  Diabetes mellitus is associated with coronary dysfunction, contributing to a 2- to 4-fold increase in the risk of coronary heart diseases. The mechanisms by which diabetes induces vasculopathy involve endothelial-dependent and -independent vascular dysfunction in both type 1 and type 2 diabetes mellitus. The purpose of this study is to determine the role of vascular large conductance Ca²⁺-activated K⁺ (BK) channel activities in coronary dysfunction in streptozotocin-induced diabetic rats.

Methods  Using videomicroscopy, immunoblotting, fluorescent assay and patch clamp techniques, we investigated the coronary BK channel activities and BK channel-mediated coronary vasoreactivity in streptozotocin-induced diabetic rats.

Results  BK currents (defined as the iberiotoxin-sensitive K⁺ component) contribute (65±4)% of the total K⁺ currents in freshly isolated coronary smooth muscle cells and >50% of the contraction of the inner diameter of coronary arteries from normal rats. However, BK current density is remarkably reduced in coronary smooth muscle cells of streptozotocin-induced diabetic rats, leading to an increase in coronary artery tension. BK channel activity in response to free Ca²⁺ is impaired in diabetic rats. Moreover, cytoplasmic application of DHS-1 (a specific BK channel b₁ subunit activator) robustly enhanced the open probability of BK channels in coronary smooth muscle cells of normal rats. In diabetic rats, the DHS-1 effect was diminished in the presence of 200 nmol/L Ca²⁺ and was significantly attenuated in the presence of high free calcium concentration, i.e., 1 mmol/L Ca²⁺. Immunoblotting experiments confirmed that there was a 2-fold decrease in BK-b₁ protein expression in diabetic vessels, without altering the BK channel α-subunit expression. Although the cytosolic Ca²⁺ concentration of coronary arterial smooth muscle cells was increased from (103±23) nmol/L (n=5) of control rats to (193±22) nmol/L (n=6, P <0.05) of STZ-induced diabetic rats, reduced BK-b₁ expression made these channels less sensitive to intracellular Ca²⁺, which in turn led to enhanced smooth muscle contraction.

Conclusions  Our results indicated that BK channels are the key determinant of coronary arterial tone. Impaired BK channel function in diabetes mellitus is associated with down-regulation of BK-b₁ expression and reduction of the b₁-mediated BK channel activation in diabetic vessels.

     

天麻素血药浓度测定及药动学研究

目的 建立天麻素血浆药物浓度LC-MS/MS测定法,测定健康受试者血浆中天麻素的浓度并评价天麻素胶囊的药动学。方法 建立以阿昔洛韦为内标的天麻素血药浓度LC-MS/MS测定方法,色谱柱为Atlantics T3(100 mm×3.0 mm,3 μm),流动相为乙腈-水(10∶90),对18名健康受试者单剂量口服150 mg天麻素胶囊进行药动学研究。结果 建立了简单、专属的天麻素血浆药物浓度的LC-MS/MS测定法,以沉淀法进行样品前处理,无杂质干扰测定,灵敏度达到了3.00 ng&#8729;mL^-1,每个生物样品分析时间仅为2 min。18名健康受试者口服天麻素胶囊150 mg后,测定血浆样品并估算天麻素的药动学参数,T_max均值为(0.8±0.3)h,t_1/2均值为(2.1±0.4)h,C_max均值为(378±84)ng&#8729;mL^-1,AUC_0-12 均值为(878±175)ng&#8729;h&#8729;mL^-1,AUC_0-∞均值为(897±175)ng&#8729;h&#8729;mL^-1。结论 本法快速、准确、灵敏度高且前处理简单,能很好的应用于药动学研究。     

Hydrogen sulfide and vascular relaxation

Objective  To review the vasorelaxant effects of hydrogen sulfide (H₂S) in arterial rings in the cardiovascular system under both physiological and pathophysiological conditions and the possible mechanisms involved.

Data sources  The data in this review were obtained from Medline and Pubmed sources from 1997 to 2011 using the search terms “hydrogen sulfide” and “vascular relaxation”.

Study selection  Articles describing the role of hydrogen sulfide in the regulation of vascular activity and its vasorelaxant effects were selected.

Results  H₂S plays an important role in the regulation of cardiovascular tone. The vasomodulatory effects of H₂S depend on factors including concentration, species and tissue type. The H₂S donor, sodium hydrosulfide (NaHS), causes vasorelaxation of rat isolated aortic rings in a dose-dependent manner. This effect was more pronounced than that observed in pulmonary arterial rings. The expression of K_ATP channel proteins and mRNA in the aortic rings was increased compared with pulmonary artery rings. H₂S is involved in the pathogenesis of a variety of cardiovascular diseases. Downregulation of the endogenous H₂S pathway is an important factor in the pathogenesis of cardiovascular diseases. The vasorelaxant effects of H₂S have been shown to be mediated by activation of K_ATP channels in vascular smooth muscle cells and via the induction of acidification due to activation of the Cl^-/HCO₃^- exchanger. It is speculated that the mechanisms underlying the vasoconstrictive function of H₂S in the aortic rings involves decreased NO production and inhibition of cAMP accumulation.

Conclusion  H₂S is an important endogenous gasotransmitter in the cardiovascular system and acts as a modulator of vascular tone in the homeostatic regulation of blood pressure.

     

肾移植术后环孢素A血药浓度监测及其体内吸收评价

目的 探讨肾移植术后稳定患者口服微乳化环孢素A(CsA-ME)的剂量与其血药浓度谷值(C₀)和给药后2 h的血药浓度(C₂)的关系及其随时间的变化趋势,从而评价CsA-ME的体内吸收过程。方法 采用荧光免疫偏振法(FPIA)对92例肾移植患者术后不同时间内测定全血中环孢素A的C₀和C₂浓度,并分别与每位患者每日每千克体重的用药剂量(ND)相比,得出其相应的浓度(即C₀/ND,C₂/ND)。计算C₂/C₀比值并对所得数据进行统计分析。结果 肾移植患者术后1~3个月内,C₀/ND和C₂/ND均增加。C₀/ND从(43±15)增加到(56±20) (ng·mL^-1)/(mg·kg^-1),C₂/ND从(129±62)增加到(212±80) (ng·mL^-1)/(mg·kg^-1),表明药物的吸收逐渐增加。但术后3~12个月内,C₂/ND维持原有水平,C₀/ND则逐渐降低为48±15 (ng·mL^-1)/(mg·kg^-1),C₂/C₀比值则从4.5±1.9逐渐增加至5.2±2.3,表明药物在体内的消除代谢逐渐增加。术后3~12个月内,C₂/ND的个体间变异系数明显小于C₀/ND的个体间变异系数。结论 肾移植患者服用CsA-ME在术后3~12月内,其环孢素A在体内的累积清除率逐渐增加,表明术后一年内单纯用C₀作为监测指标已不能准确预测CsA-ME在体内的药物暴露总量,应结合C₂监测对于提高个体化的治疗将更有临床意义。     

复方氨酚曲马多片中对乙酰氨基酚的人体药代动力学研究

目的 研究氨酚曲马多片在中国健康人体内的药代动力学特性。方法 10名健康志愿者(男女各半)单剂量口服2片氨酚曲马多片（每片曲马多/对乙酰氨基酚为37.5 mg/325 mg）。对乙酰氨基酚血药及尿药浓度采用高效液相色谱-紫外（HPLC-UV）检测法测定。结果 受试者单次口服给药后,以HPLC-UV法测血浆及尿液中对乙酰氨基酚浓度。采用DAS软件计算对乙酰氨基酚的药代参数。C_max为(10.95±7.85)mg·L^-1,T_max为(0.83±0.29)h,t_1/2为(2.09±0.34)h,AUC_0～24为(26.93±11.64)mg·h·L^-1,AUC_0-∞为(27.74±11.57)mg·h·L^-1,尿液中24 h以原形排泄百分比(2.90±1.32)%;受试者各项检查未见异常,无不良反应发生。结论 对血浆药代动力学参数及尿中药物排泄量进行性别单因素方差分析,结果未显示性别差异。该药在试验剂量下具有良好的安全性。     

复方苯磺酸氨氯地平/盐酸贝那普利片人体药动学研究

目的 研究健康受试者单剂量与多剂量口服复方苯磺酸氨氯地平/盐酸贝那普利片后的药动学。 方法 LC-MS/MS测定单剂量与多剂量给药后氨氯地平与贝那普利及贝那普利拉血药浓度并利用DAS软件计算药动学参数。结果 单剂量给药氨氯地平与贝那普利及贝那普利拉的主要药动学参数分别是：t_1/2为(47.3±10.6),(1.3±0.4)和(4.5±0.6) h,C_max为(6.4±1.5),(136.5±40.2)和(158.3±46.7)μg·L^-1,AUC_0-t为(267.7±88.4),(144.3±46.7)和(891.4±265.4)μg·h·L^-1;多剂量给药氨氯地平与贝那普利的主要药动学参数分别是：t_1/2为(45.1±8.7),(1.4±0.4)和(5.3±0.8)h,C_max为(8.2±1.8),(142.4±47.5)和(165.2±40.8)μg·L^-1,AUC_0-t为(413.5±102.4),(155.7±52.8)和(915.7±316.9)μg·h·L^-1,R为(1.6±0.6)、(1.0±0.1)和(1.2±0.1)。结论 复方苯磺酸氨氯地平/盐酸贝那普利片2组分及活性代谢产物在健康受试者体内的吸收速率和消除速度不随连续给药变化,但连续给药后苯磺酸氨氯地平在体内有轻微蓄积。     

液相色谱-串联质谱法测定阿德福韦及其前体化合物在大鼠血浆中的浓度

目的 建立测定大鼠血浆中阿德福韦（PMEA）及其前体药物APD2、PMEA-CA的液相色谱-串联质谱(LC-MS/MS)法。方法 分别采用不同的血浆样品处理方法和色谱条件测定PMEA及其前体化合物。测定PMEA时,血浆样品经甲醇沉淀蛋白后,用Discovery C₁₈柱分离,以甲醇-0.5％甲酸（20∶80,V/V）为流动相,9-(3-膦酸甲氧基丙基)腺嘌呤为内标,采用ESI源以多反应监测方式对血浆样品中的PMEA进行定量分析。测定APD2和PMEA-CA时,血浆样品经固相萃取后,用Hypersil ODS2柱分离,以甲醇-5 mmol·L^-1乙酸铵（70∶30,V/V）为流动相,格列本脲为内标,采用ESI源以多反应监测方式对血浆中APD2和PMEA-CA进行定量分析。结果 PMEA和PMEA-CA线性范围为25～5 000 μg·L^-1,ADP2的线性范围为10～2 500 μg·L^-1,日内、日间精密度均<5.5 %。结论 本方法专属性强、灵敏度高,适用于PMEA前体药APD2及PMEA-CA的临床前药代动力学研究。