用细口径反相柱HPLC分离多种前列腺素

HPLC与放射性同位素联用,可同时分离鉴定多种花生四烯酸代谢产物。目前国外一般是使用普通口径(4.6 mm)的反相柱,以30%左右乙腈为流动相,流速为1～3 ml/min。这种HPLC方法乙腈用量较大,费用太贵,不适合国内实验室常规操作。据报道,细口径     

摆动从动杆盘状凸轮机构的运动设计——同时考虑压力角和最小曲率半径的优化设计

本文对摆动从动杆盘状凸轮机构的最大压力角和最小曲率半径问题进行了详细的讨论。根据优化原理,同时考虑许用压力角和最小曲率半径,对摆动从动杆盘状凸轮机构进行了最优化设计。在仅给出摆杆运动规律、摆杆最大摆角和相应凸轮转角的情况下,直接确定凸轮的最小基圆半径、摆杆长度和摆杆初始位置角。     

Usefulness of whole blood aggregometry and its comparison with thromboxane generation assay in monitoring acetylsalicylic acid effectiveness--a multiparametric study in rats.

BACKGROUND: There is a need for consensus concerning universal methodological criteria for detection of suboptimal response to acetylsalicylic acid (ASA) therapy. Therefore, animal models to test for ASA effectiveness remain of interest. Our objective was to verify the usefulness of multiparametric whole-blood impedance aggregometry and thromboxane A(2) generation, which are the most popular techniques used for monitoring of ASA treatment effectiveness. METHODS: Using multiparametric analysis of whole-blood impedance aggregometry, we examined which parameters of platelet aggregation or disaggregation allow for the best discrimination between ASA-treated (4 or 40 mg/kg for 60 days) and non-treated male rats. The effectiveness of ASA-mediated inhibition of platelet cyclooxygenase-1 was verified by determination of plasma thromboxane B(2) and urine 11-dehydro-thromboxane B(2), accepted as reference assays for monitoring of ASA-mediated platelet cyclooxygenase-1 inhibition. RESULTS: Two of the platelet agonists used, collagen (1 mg/L) and arachidonic acid (0.5 mmol/L), allowed discrimination of control and ASA-treated animals, whereas adenosine diphosphate (5 micromol/L) was not effective. It is noteworthy that only ASA-mediated changes in duration of the rising phase for platelet aggregation and the area under the curve for collagen-induced aggregation allowed significant discrimination between low and high ASA dose and remained correlated with the reference parameter, plasma thromboxane B(2). CONCLUSIONS: Analysis of aggregation curves, routinely based only on the amplitude and rate of platelet aggregation, may not be enough discriminative to distinguish between varying ASA doses and treatment schedules.     

雪灵芝对二乙基亚硝胺诱导大鼠肝癌组织细胞的抑制作用

目的：验证雪灵芝是否具有抑制大鼠肝癌的功效。方法：实验于2003—09/2004—08在广西疾病预防控制中心SPF级动物实验室完成。选用健康成年SD大鼠160只。按体质量分层随机分为5组：空白对照组、模型组、雪灵芝高剂量组、雪灵芝中剂量组和雪灵芝低剂量组，每组32只。雪灵芝高、中、低剂量组大鼠分别灌胃2．500，1．250，0．625mL/kg雪灵芝溶液，阴性对照组和模型组灌胃等量蒸馏水，1次／d，连续60d。第61天开始雪灵芝高、中、低剂量组和模型组灌胃二乙基亚硝胺溶液，对照组灌胃等量的生理盐水。于停止灌胃90d后各组处死一半受试大鼠（雌雄各半），检测血常规及血清主要生化指标，观察各脏器大体形态改变、脏器的癌变程度。1周后给剩余大鼠灌胃雪灵芝溶液（不含二乙基亚硝胺）。7周后处死余下的一半雄性大鼠，进行相同操作。8周后处死余下的全部大鼠，操作及检测方法同前。结果：纳入的160只SD大鼠，145只进入结果分析，15只脱落。①病理切片检查结果：除阴性对照组，其他各组大鼠肝组织均发生癌变或癌前病变。雪灵芝高、中、低剂量组的癌前病变发生率与模型组相近（P〉0．05）；癌变的发生率均低于模型组，差异有显著性意义（P〈0．05，0．01）。②大体标本检查结果：阴性对照组大鼠肝脏的大体标本均无异常改变，其他各组大鼠的肝脏有些可见表面粗糙等病理改变。模型组大体标本病理改变的阳性率高于雪灵芝高、中、低剂量组，差异有显著性意义（P〈0．05）。肉眼观模型组癌变发生率高于其他各组。③其他脏器检查结果：模型组2只大鼠有肝癌肺转移。结论：以较大剂量的二乙基亚硝胺连续灌胃30d可以复制大鼠肝癌模型；雪灵芝对二乙基亚硝胺诱导的大鼠肝癌具有预防和抑制的作用。     

Plasma matrix metalloproteinase-3 level is an independent prognostic factor in stable coronary artery disease

BACKGROUND: Recent evidence suggests the important role of matrix metalloproteinases (MMPs) in the progression of atherosclerosis and development of clinical events. We assessed the prognostic value of different plasma MMPs in patients with stable coronary artery disease (CAD). MATERIALS AND METHODS: A total of 165 consecutive nondiabetic patients with angiographically significant CAD (n = 150) or normal coronary angiograms despite exercise-induced myocardial ischemia (cardiac syndrome X, n = 15) and 17 normal subjects were evaluated. In each subject, plasma inflammatory markers including high sensitivity C-reactive protein (hsCRP) and MMP-2, 3 and 9 were measured. In CAD patients, major cardiovascular events including cardiac death, nonfatal myocardial infarction, unscheduled coronary revascularization and hospitalization as a result of unstable angina were prospectively followed up for more than 6 months. RESULTS: Plasma levels of MMPs were significantly higher in CAD patients than in those with cardiac syndrome X and in normal subjects (MMP-2: 914.76 +/- 13.20 vs. 830.79 +/- 31.95 vs. 783.08 +/- 28.40 ng mL(-1), P = 0.002; MMP-3: 129.59 +/- 4.21 vs. 116.86 +/- 8.09 vs. 91.71 +/- 9.55 ng mL(-1), P = 0.011; MMP-9: 31.42 +/- 2.84 vs. 11.40 +/- 5.49 vs. 6.71 +/- 2.89 ng mL(-1), P = 0.006). In CAD patients, there were 48 major cardiovascular events during a mean follow-up period of 17.74 +/- 0.85 months. The numbers of diseased vessels (HR = 2.19, 95% CI 1.20-1.02, P = 0.011), plasma hsCRP (HR = 2.21, 95% CI 1.18-4.11, P = 0.013) and MMP-3 level (HR = 2.46, 95% CI = 1.15-5.28, P = 0.021) were associated with the development of cardiovascular events. However, only the plasma MMP-3 level was an independent predictor of the adverse events in CAD patients (HR = 2.47, 95% CI 1.10-5.54, P = 0.028). CONCLUSIONS: Plasma MMP levels were increased in CAD patients. Plasma MMP-3 level, rather than hsCRP, was an independent prognostic marker for future cardiovascular events, suggesting its potential role in risk stratification and clinical management of stable CAD.     

Antimicrobial resistance of Streptococcus pneumoniae isolated in Taiwan: an island-wide surveillance study between 1996 and 1997

Between August 1996 and July 1997, 550 clinically significant Streptococcus pneumoniae isolates were collected from 14 geographically separate laboratories in Taiwan. These isolates were serotyped and MICs were determined by agar dilution. Among serotypes covered by the 23-valent vaccine, types 19F, 19A, 23F, 23A and 6B dominated, comprising 255 isolates; among non-vaccine serotypes, types 35, 39, 34, 13 and 31 dominated, comprising 118 isolates. Of the 550 isolates, 310 (56.4%) were resistant to penicillin G (MIC 0. 12 mg/L), 238 (43.3%) with intermediate resistance (MIC 0.12-1 mg/L) and 72 (13.1%) with high-level resistance (MIC 2 mg/L). Most non-susceptible pneumococci were of serotypes 19F and 23F; non-susceptible isolates of these serotypes were distributed across all of Taiwan. Fourteen other antibiotics were tested; 83% of the isolates were resistant to tetracycline, 78% to azithromycin, 74% to erythromycin, 54% to clindamycin and 23% to chloramphenicol. Thus, macrolides can no longer be used as first line agents to treat pneumococcal infections in Taiwan. Multi-resistance (isolates resistant to three or more chemically unrelated antibiotics) was found in each serotype or group, but mostly in types 19F and 23F. The emergence of such strains complicates antibiotic selection, but both types are covered by the 23-valent vaccine, as were 82% of the isolates from blood and eight of the nine from cerebrospinal fluid. Good antibiotic control and appropriate use of this vaccine may improve the current problem in Taiwan, especially for the elderly.