Development of An ICR Mouse Bioassay for Toxicity Evaluatition in Neurotoxic Poistioning Toxins-Ctiontaminated Shellfish

Objective To develop an ICR (female) mouse bioassay (MBA) for toxicity confirmation and evaluation of neurotoxins (brevetoxins)-contaminated shellfish. Methods Brevetoxins (BTX-B) as a causative agent of neurotoxic shellfish poisoning (NSP) under different shellfish matrices were intraperitoneally injected at different doses into mice to study their toxic effects and to differentiate the range of lethal and sublethal dosages. Their sensitivity and specificity were analyzed with 2 competitive ELISA kits for quantitative determination of standard BTX-B and dihydroBTX-B under different shellfish matrix-diluent combinations. Detection rates of MBA and two antibody-based assays for BTX-B from field NSP-positive shellfish samples were compared. Results BTX-B could be detected in shellfish tissues at concentration of 50-400 μg/100 g under shellfish matrix-Tween-saline media, which were appropriate to identify toxic shellfish at or above the regulatory limit (80 μg/100 g shellfish tissues). The LD 50 identified was 455 g/kg for BTX-B under general shellfish matrices (excluding oyster matrices) dissolved in Tween-saline. The presence of shellfish matrices, of oyster matrices in particular, retarded the occurrence of death and toxicity presentation in mice. Two antibody-based assays, even in the presence of different shellfish matrix-diluent combinations, showed acceptable results in quantifying BTX-B and dihydroBTX-B well below the regulatory limit. Conclusion The two ELISA analyses agree favorably (correlation coefficient, r 0.96; Student’s t-tests, P>0.05) with the developed bioassay.     

Right Ventricular Septal Pacing: The Success of Stylet-Driven Active-Fixation Leads

Background: The detrimental effects of right ventricular (RV) apical pacing on left ventricular function has driven interest in alternative pacing sites and in particular the mid RV septum and RV outflow tract (RVOT). RV septal lead positioning can be successfully achieved with a specifically shaped stylet and confirmed by the left anterior oblique (LAO) fluoroscopic projection. Such a projection is neither always used nor available during pacemaker implantation. The aim of this study was to evaluate how effective is the stylet-driven technique in septal lead placement guided only by posterior-anterior (PA) fluoroscopic view.
Methods: One hundred consecutive patients with an indication for single- or dual-chamber pacing were enrolled. RV septal lead positioning was attempted in the PA projection only and confirmed by the LAO projection at the end of the procedure.
Results: The RV lead position was septal in 90% of the patients. This included mid RV in 56 and RVOT in 34 patients. There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites . In the RVOT, 97% (34/35) of leads were placed on the septum, whereas in the mid RV the value was 89% (56/63).
Conclusions: The study confirms that conventional active-fixation pacing leads can be successfully and safely deployed onto the RV septum using a purposely-shaped stylet guided only by the PA fluoroscopic projection. (PACE 2010; 49–53)     

Impact of Right Ventricular Pacing Sites on Exercise Capacity during Ventricular Rate Regularization in Patients with Permanent Atrial Fibrillation

Background: The deleterious effects of right ventricular apical (RVA) pacing may offset the potential benefit of ventricular rate (VR) regularization and rate adaptation during an exercise in patient's atrial fibrillation (AF). Methods: We studied 30 patients with permanent AF and symptomatic bradycardia who receive pacemaker implantation with RVA (n = 15) or right ventricular septal (RVS, n = 15) pacing. All the patients underwent an acute cardiopulmonary exercise testing using VVI‐mode (VVI‐OFF) and VVI‐mode with VR regularization (VRR) algorithm on (VVI‐ON). Results: There were no significant differences in the baseline characteristics between the two groups, except pacing QRS duration was significantly shorter during RVS pacing than RVA pacing (138.9 ± 5 vs 158.4 ± 6.1 ms, P = 0.035). Overall, VVI‐ON mode increased the peak exercise VR, exercise time, metabolic equivalents (METs), and peak oxygen consumption (VO₂max), and decreased the VR variability compared with VVI‐OFF mode during exercise (P < 0.05), suggesting that VRR pacing improved exercise capacity during exercise. However, further analysis on the impact of VRR pacing with different pacing sites revealed that only patients with RVS pacing but not patients with RVA pacing had significant increased exercise time, METs, and VO₂max during VVI‐ON compared with VVI‐OFF, despite similar changes in peaked exercise VR and VR variability. Conclusion: In patients with permanent AF, VRR pacing at RVS, but not at RVA, improved exercise capacity during exercise.     

畲药树参茎化学成分分析及抗炎活性部位高效液相指纹图谱的建立

目的 对畲药树参茎所含化学成分进行确证分析,并建立抗炎活性部位的高效液相色谱指纹图谱。方法 采用液相色谱-质谱联用、核磁共振波谱仪等分析仪器分离鉴定树参茎中的化学成分;采用高效液相色谱法建立抗炎活性部位指纹图谱：色谱柱为Waters Sunfire^TM C₁₈(4.6 mm×250 mm,5 μm),流动相为乙腈-混合水溶液(含甲酸0.2%和四氢呋喃0.2%),梯度洗脱。检测波长为256 nm,柱温30 ℃,体积流量为1.0 mL·mim^–1,分析时间为80 min,进样量为5 μL。结果 从树参茎中共分离鉴定出10个化合物,分别是绿原酸(1)、3,4-O-二咖啡酰基奎宁酸(2)、3,5-O-二咖啡酰基奎宁酸(3)、4,5-O-二咖啡酰基奎宁酸(4)、saikolignanoside A(5)、芦丁(6)、山柰酚-3-O-芸香糖苷(7)、紫丁香苷(8)、松柏醇(9)、芥子醛葡萄糖苷(10);12批样品抗炎活性部位指纹图谱相似度为0.901~0.992,均符合要求。结论 树参茎中主要含有酚酸类、黄酮类、苯丙素类化合物;建立的指纹图谱不仅能体现树参茎抗炎的化学物质基础,而且鉴别方法简便、重复性好,可为树参茎的品质评价及主要抗炎活性成分的确证提供科学依据。     

基于指纹图谱结合化学模式识别对狗脊药材的质量评价

目的 采用指纹图谱结合聚类分析（hierarchical clustering analysis,HCA）、主成分分析（principal component analysis,PCA）和偏最小二乘法-判别分析（partial least squares discriminant analysis,PLS-DA）等进行化学模式识别,对狗脊药材指纹图谱数据进行分析,筛选特征性指标成分并以此建立狗脊有效成分的定量分析,为狗脊质量控制提供科学依据。方法 采用Agilent Eclipse XDB-C18柱（250 mm×4.6mm,5.0μm）,以甲醇-1%醋酸水溶液为流动相进行梯度洗脱,体积流量为1.0 mL/min,柱温为30℃,检测波长为280 nm,HPLC法建立9个产地16批样品狗脊的指纹图谱,运用相似度分析、HCA、PCA和PLS-DA等化学模式识别技术筛选出不同产地狗脊化学成分的特征成分作为狗脊有效成分,并定量分析。结果 16批狗脊HPLC指纹图谱标定10个共有峰,相似度在0.695～0.954;通过HCA、PCA和PLS-DA较好的区分各产地狗脊,综合分析筛选5-羟甲基糠醛、...     

急性胆管炎内镜置管引流162例体会

文章总结了１６２例因胆石引起的急性胆管炎采用内镜置管引流的临床体会。１４３例引流通畅，胆汁引流量２００～６００ｍｌ／ｄ，病人症状在置管后迅速缓解，可以达到急诊手术引流的效果。１２例导管未能通过高位梗阻部位，７例胆管内大量结石，泥沙及脓性絮状物堵塞导管引流不畅，而中转手术。作者认为：成功的置管引流，胆道减压迅速，可有效地控制感染，改善中毒症状并减轻黄疸。急性期后，可应用导管造影明确胆道系统的病理改变，及滴入药物治疗或溶石。内镜置管可重复，并发症少，为择期进行确定性治疗创造条件。     

Changes in the levels of house dust mite specific IgG4 during immunotherapy in asthmatic children

Serum levels of IgG subclass and house dust mite (Dermatophagoides pteronyssinus, Dpt) specific IgG4 were evaluated during immunotherapy in asthmatic children. Asthmatic children undergoing long-term immunotherapy (more than 2 years) posed a mean value of total serum IgG4 or Dpt-specific IgG4 antibodies significantly higher than that of patients prior to receiving immunotherapy, asthmatic (placebo) controls, or patients undergoing short-term immunotherapy (less than 1 year) (P less than 0.05). The mean levels of serum Dpt-specific IgG4 in all asthmatic groups were also significantly higher than in the non-allergic controls (P less than 0.01). Moreover, the mean level of Dpt-specific IgG4 tended to increase during immunotherapy. A significant correlation between total serum IgG4 and Dpt-specific IgG4 antibodies was noted (r = 0.6243; P less than 0.001). Serial follow-up reveals that Dpt-specific IgG4 levels usually rose significantly with clinical improvement in asthmatic children during immunotherapy. These results suggest that the anti-mite-specific IgG4 antibody may serve as an indicator for clinical outcome of mite allergy during immunotherapy.     

PERICARDITIS ASSOCIATED WITH TICK-BORNE Q FEVER

A case of pericarditis associated with Q fever is described. Transmission was probably via an arthropod vector, which was most likely the kangaroo tick Amblyomma triguttatum. Complete recovery occurred in association with the use of non-steroidal anti-inflammatory agents only. This is a rare presentation of Q fever implicating transmission by a novel vector.     

Dynamic stiffness and implications for assisting the operation of the left ventricle

The distribution of bending strain and stiffness in the wallof the left ventricle (LV) is relevant to the augmentation ofits function by a modified skeletal-muscle wrap in the new surgicalprocedure of cardiomyoplasty. A novel approach to ventricularmechanics is presented which blends some finite-element resultsin engineering with new data available on ventricular geometry.Two simplified axisymmetric strip-element models of the LV areused to illustrate aspects of myocardial stiffness in the bending-strain-energydistribution and the effect on wrap synchronization of a changein cross-fibre stiffness when the heart has nonuniform or ectopicbeats. The nonlinear and time-dependent nature of both dampingand wall stiffness is derived from differential equations governingthe dynamic paths from systole to diastole of finite wall elementsaround the periphery of an oblique LV slice using magnetic resonanceimaging (MRI) data. This leads to a geometric method for determiningthese parameters. Results for time-dependent stiffnesses ofelements in their trajectories are presented for a normal heart.