Anisodamine inhibits cardiac contraction and intracellular Ca(2+) transients in isolated adult rat ventricular myocytes

Increased cardiac workload often leads to serious complications during cardiac surgery such as pericardiopulmonary bypass. Various agents have been applied to lower peripheral resistance and cardiac workload, one of which, anisodamine, is widely used in Asia. However, the direct action of anisodamine on cardiac contractile property is essentially unknown. This study was designed to examine the influence of anisodamine on ventricular contractile function at the single cardiac myocyte level. Ventricular myocytes from adult rat hearts were stimulated to contract at 0.5 Hz, and mechanical and intracellular Ca(2+) properties were evaluated using an IonOptix Myocam system. Contractile properties analyzed included peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR(90)), maximal velocity of shortening/relengthening (+/-dL/dt), intracellular Ca(2+) fluorescence intensity change (DeltaFFI) and decay (tau). Anisodamine exhibited a concentration-dependent (10(-12)-10(-6) M) inhibition in PS and DeltaFFI, with maximal inhibitions of 44.7% and 47.2%, respectively. Anisodamine inhibited +/-dL/dt, lowered resting FFI but elicited no effect on TPS/TR(90) and tau. Pretreatment with the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM) abolished the inhibitory effect of anisodamine in cell shortening. In addition, anisodamine prevented cholinoceptor agonist carbachol-induced positive cardiac contractile response. This study demonstrated a direct cardiac depressive action of anisodamine at the myocyte level, which may be related to, at least in part, NO production and cholinoceptor antagonism.     

Case studies in PET

In recent years primary care providers have been increasingly called on to broaden their management of patients, particularly in their role as gatekeepers to reduce healthcare costs. Obviously a wide spectrum of specialty involvement exists, ranging from the classic family practitioner managing all of the common diseases and referring challenging cases to specialists, to the internist with a background and interest geared toward handling more specialized neurologic, cardiac, or oncologic diseases. Whatever the case, primary care providers can have a great impact on diagnosis and management of illness by consulting with the radiologist about the use of the emerging technology of positron emission tomography (PET).     

阿司匹林和塞莱昔布对幽门螺杆菌的体外影响

目的:探讨阿斯匹林和选择性COX-2抑制剂塞莱昔布对体外培养的幽门螺杆菌(H pylori)生长、毒力因子及外膜蛋白的影响．方法:不同浓度的阿司匹林及塞莱昔布与H pylori共同培养,以活菌计数、分光光度计法检测H pylori的生长状态,分光光度计检测A 560nm值判断尿素酶活性,Hela细胞空泡变性实验和中性红吸收试验检测空泡毒素的活性,以SDS-PAGE电泳检测H pylori外膜蛋白的变化．结果:阿司匹林及塞莱昔布可以抑制H pylori的生长,此过程为剂量依赖性效应．阿司匹林0．5 mmol／L及塞莱昔布0．01 mmol／L时与DMSO对照相比H pylori24 h和48 h的菌落计数开始降低,随着两药剂量的加大菌落计数降低得更加明显,阿司匹林2．0 mmol/L和塞莱昔布0．04 mmol／L时H pylori被完全杀灭．阿司匹林及塞莱昔布可剂量依赖性的抑制H pylori的尿素酶活性及空泡毒素的活性．在对H pylori外膜蛋白的研究中发现,NSAIDs可能对H pylori的某种外膜蛋白表达有影响．结论:阿司匹林和塞莱昔布可抑制H pylori的生长、毒力因子的活性,并可能改变H pylori外膜蛋白的表达．     

体表高频超声技术评价家兔血管成形术后再狭窄模型与病理学结果的相关性

目的:分析体表高频超声检测家兔血管内球囊成形术后再狭窄程度与组织病理学分析的相关性。评估体表超声检测的可行性、可靠性及应用价值。方法:实验于2002-03/2003-12在北京中医药大学中医内科学重点学科实验室完成。①日本大耳白兔26只,随机分为正常组10只、假手术组6只、模型组10只。②模型组电刺激兔颈总动脉,电流1.2mA,刺激12～15min,术后第2天喂饲高脂饲料共8周,假手术组仅剥离颈总动脉,不做电刺激,喂高脂饲料,正常组不施加任何干预因素。③模型组和假手术组根据B超选择颈总动脉有斑块或血流明显改变者行球囊血管内成形术。分别于电刺激后8周、血管成形术后4周行超声检查动脉内径和动脉内膜厚度。④所有动物于血管成形术后4周处死取材,进行病理学半定量分析,并与超声测量结果进行相关分析。结果:进入结果分析数量24只,正常组中途死亡1只,原因为牙齿畸型影响进食。模型组1只因电刺激8周时超声评价颈动脉未形成斑块及血流无明显改变而剔出实验。①超声检测电刺激8周时正常组内膜厚为(0.028±0.004)cm,模型组管壁明显增厚(0.043±0.014)cm,差异有显著性(P<0.05),至血管成形术后膜厚增加更明显(0.064±0.002)cm,内径稍有扩大,但差异不显著。②超声检测模型组颈动脉内径与膜厚的测量结果与病理学测量结果呈正相关关系(OR=0.361,P<0.05;OR=0.526,P<0.01),病理狭窄率与超声是否检测到斑块呈正相关关系(OR=0.796,P<0.01)。结论:体表高频超声在评价家兔颈动脉狭窄诊断中有一定应用价值,与病理学半定量分析结果相关性良好。     

Peripubertal ontogeny and estrogen stimulation of cholecystokinin and preproenkephalin mRNA in the rat hypothalamus and limbic system

The neuropeptide cholecystokinin (CCK) is expressed in limbic system and hypothalamic nuclei that form a circuit that regulates the display of the female rodent reproductive behavior, lordosis. CCK mRNA and peptide levels fluctuate across the estrous cycle and have been shown to be modulated by estrogen exposure. The objective of these experiments was to examine the expression of CCK mRNA during postnatal development of this limbic-hypothalamic, lordosis regulating circuit, and to determine the age at which CCK mRNA expression becomes responsive to estrogen stimulation, by using quantitative in situ hybridization histochemistry. CCK mRNA levels were below the level of detectability within the circuit during the postnatal period, but increased during the peripubertal period. Rats were injected with either estradiol benzoate (EB), EB and progesterone, progesterone, or oil, and were killed 48 hours later on postnatal day (PND) 15, 20, and 25. Alternate brain sections were processed for CCK and preproenkephalin (PPE) mRNA in situ hybridization histochemistry. EB treatment induced CCK mRNA expression in the central portion of the medial preoptic nucleus and posterodorsal medial amygdala at PND 20 and 25, respectively. However, EB treatment increased PPE mRNA levels within the nuclei of the circuit at all ages examined. Progesterone had neither an independent nor additive effect on the EB induction of these neuropeptide messages. The estrogenic induction of CCK mRNA appears to be dependent on estrogen sensitive pathways of neurotransmission, or components of second messenger pathways which regulate CCK mRNA expression in the adult limbic-hypothalamic lordosis regulating circuit, which are not functional before PND 18–25. J. Comp. Neurol. 392:48–57, 1998. © 1998 Wiley-Liss, Inc.     

Teacher probation — An outdated concept?

Should the end result of the evaluation process in education be teacher probation? What is causing a high percentage of teachers in their first five years of teaching to be put on probation? Why are a high percentage of teachers in their eleventh to fifteenth years of teaching ending up on probation? Can discipline be removed from proficiency in other areas of teaching? How many areas must a certified employee be judged deficient in before being placed on probation? Do the evaluative criteria used in the evaluation instrument result in the improvement of instruction or the improvement of the teaching/learning process? What is the role of the principal in the evaluative/probationary process? What should the evaluative process be in education? Is teacher probation a failure of the system to provide the type of growth-oriented process needed by teachers?

These questions are examined as the responses of superintendents in Washington State School districts are analyzed. Their responses were gathered in a study conducted by an Eastern Washington University Department of Education research team.     

Simultaneous multi-site EPR spectroscopy in vivo

A gradient technique to measure electron paramagnetic resonance spectra simultaneously at several different locations is described. The technique is based on the use of point probes containing paramagnetic centers. The value of the magnetic field gradient is chosen to be sufficient to separate the EPR signals from the different paramagnetic probes yet at the same time small enough to change only minimally the shape of individual signals. The conditions to apply this technique are considered in detail. When experimental data have a high signal-to-noise ratio, the lineshape distortion induced by the gradient can be corrected with the aid of a known distribution function of paramagnetic centers within the probe. The maximum entropy deconvolution algorithm is successfully applied for the correction of significantly distorted lines. The technique is experimentally tested and applied to measure the concentration of oxygen in hypertrophied rat myocardium and normal rat kidney in vivo by low frequency EPR (L-band, 1.2 GHz). No types of EPR oxygen-sensitive probes-lithium phthalocyanine crystals and synthetic carbohydrate chars-were used.     

Environmental factors and refractive error in Chinese schoolchildren

We surveyed and assessed 2,323 schoolchildren aged seven to 17 years from four schools in China, two in the city of Tianjin and the other two in a neighbouring rural village, Ban Chau, to investigate the prevalence of refractive error and its relationship with environmental factors. Every child from each of the participating classes was recruited in this study to avoid self-selection. A questionnaire was issued which queried some aspects of the child's visual habits and home. Refraction was canied out using the Canon R-22 autorefractor. The degree and frequency of myopia in these children increased almost linearly from age seven to 17 years. There was little difference between the urban and rural groups. Of the factors explored, the number of hours spent on near work showed the best correlation with the degree of myopia, albeit only weakly.     

Reactive oxygen species and acute renal failure

Acute renal failure is commonly due to acute tubular necrosis (ATN), the latter representing an acute, usually reversible loss of renal function incurred from ischemic or nephrotoxic insults occurring singly or in combination. Such insults instigate a number of processes-hemodynamic alterations, aberrant vascular responses, sublethal and lethal cell damage, inflammatory responses, and nephron obstruction-that initiate and maintain ATN. Eventually, reparative and regenerative processes facilitate the resolution of renal injury and the recovery of renal function. Focusing mainly on ischemic ATN, this article reviews evidence indicating that the inordinate or aberrant generation of reactive oxygen species (ROS) may contribute to the initiation and maintenance of ATN. This review also discusses the possibility that ROS may instigate adaptive as well as maladaptive responses in the kidney with ATN, and raises the possibility that ROS may participate in the recovery phase of ATN.