Catecholamine-induced alteration in sedimentation behavior of membrane bound beta-adrenergic receptors

Incubation of astrocytoma cells with catecholamines results in a decrease in catecholamine-stimulated adenylate cyclase activity and a concomitant alteration in the sedimentation properties of particulate beta-adrenergic receptors. The altered receptors exhibit agonist binding properties similar to those of receptors that are "uncoupled" from adenylate cyclase.     

A strong influence of serotonin axons on beta-adrenergic receptors in rat brain

The role of serotonin axons in modulating the norepinephrine neurotransmission system in rat brain was investigated. Selective lesions of the forebrain serotonergic system were made by injecting 5,7-dihydroxytryptamine into the midbrain raphe nuclei. Four to six weeks after the lesion, the uptake of 3H-labeled serotonin in the frontal cortex and the hippocampus was reduced by more than 90 percent, while neither the uptake of 3H-labeled norepinephrine nor the content of norepinephrine was affected in either tissue. The number of beta-adrenergic receptors, as measured by radioligand binding with 3H-labeled dihydroalprenolol, was increased in the frontal cortex and hippocampus of rats with lesions. Similarly, specific lesions of central serotonin axons produced by systemically administered p-chloramphetamine resulted in an increase in the binding of 3H-labeled dihydroalprenolol to beta-adrenergic receptors and in the production of adenosine 3',5'-monophosphate in response to isoproterenol. These results indicate that serotonin axons may regulate beta-adrenergic receptor number and function in brain.     

Epoxide-opening cascades promoted by water

Selectivity rules in organic chemistry have been inferred largely from nonaqueous environments. In contrast, enzymes operate in water, and the chemical effect of the medium change remains only partially understood. Structural characterization of the "ladder" polyether marine natural products raised a puzzle that persisted for 20 years: Although the stereochemistry of adjacent tetrahydropyran (THP) cycles would seem to arise from a biosynthetic cascade of epoxide-opening reactions, experience in organic solvents argued consistently that such a pathway would be kinetically disfavored. We report that neutral water acts as an optimal promoter for the requisite ring-opening selectivity, once a single templating THP is appended to a chain of epoxides. This strategy offers a high-yielding route to the naturally occurring ladder core and highlights the likely importance of aqueous-medium effects in underpinning certain noteworthy enzymatic selectivities.     

立体心电图对冠心病心肌缺血的诊断价值

目的 以冠状动脉造影结果作为金标准,对比分析常规12导联心电图(ECG)、向量心电图(VCG)、立体心电图(SECG)等检查对诊断冠心病心肌缺血的敏感性,评价SECG在冠心病心肌缺血诊断中的价值。方法 选择156例行冠脉造影(CAG)的患者,其中冠心病组103例,非冠心病组53例,分析其于同一心电工作站所做的ECG、VCG、SECG资料,观察比较这三种方法的检出结果。结果 SECG在诊断冠心病心肌缺血方面,检出率高于VCG、ECG,差异有统计学意义(P<0.05);SECG在诊断冠心病心肌缺血方面的灵敏度、特异度、正确指数、诊断符合率均高于VCG、ECG;SECG在诊断冠心病冠脉多支病变上与ECG、VCG无差异,在一支病变及两支病变上与ECG相比差异有统计学意义(P<0.05),检出率较ECG明显增高,而与VCG相比差异无统计学意义(P>0.05);SECG在诊断冠心病Ⅱ～Ⅲ级狭窄组中检出率较ECG明显增高(P<0.05),但与VCG相比差异无统计学意义;在完全闭塞组中,虽然SECG检出率较VCG、ECG高,但结果差异无统计学意义(P>0.05)。结论 SECG在诊断冠心病心肌缺血有一定的诊断价值,且优于VCG、ECG。     

科技引领开创种业传奇

介绍福建省为期3年的第一轮种业创新与产业化工程项目,总结该项目实施3年来的主要创新点和服务成效,并进一步分析取得成效的主要经验.     

热敏灸结合心理干预治疗无症状心肌缺血的临床观察

[摘要〕目的观察热敏灸结合心理干预治疗无症状心肌缺血的临床疗效〔方法将40例SMI患者随机分为治疗 组和对照组,每组20例〔治疗组:热敏灸治疗结合心理干预;对照组:}}服复方月一参滴丸〔结果治疗组总有效率达到 950Ic,对照组总有效率为75%治疗组和对照组患者临床疗效比较有明显的差异(P<0.05、两组均能明显减少SMI发 作次数与缩短SMI持续时间,但治疗组明显优于对照组(P<0.05 )、结论热敏灸结合心理干预治疗SMI有很好的临床 疗效及应用价值、     

多因素环境作用下对心肌缺血家兔QT间期的影响

目的探讨多因素环境刺激对心肌缺血家兔心电活动的影响。方法家兔90只,随机分心肌缺血低氧组、心肌缺血饥饿组、心肌缺血低氧饥饿高温组、心肌缺血低氧高温组、单纯心肌缺血组、单纯饥饿组、单纯高温组、单纯低氧组、正常对照组共9个组,每组10只,心肌缺血按缺血方法进行,各组分别放入相应的环境中,实验进行30min后测定各组的QT间期变化并与对照组进行对比。结果除正常对照组外,所有实验动物的QT间期出现不同程度的改变,各种环境因素变化作用于心肌缺血30min后表现为以QT间期延长为主,与正常对照比较差异均有显著性(P<0.05);与心肌缺血前比较,多因素环境变化对心肌缺血的影响也均以QT间期延长为主(P<0.05)。结论多因素的环境变化对心肌缺血家兔QT间期都有一定影响,均以QT间期延长为主。     

白细胞数量对急性心肌缺血大鼠血液流变学指标的影响

目的探讨白细胞数量对急性心肌缺血大鼠血液流变性的影响.方法用Wistar大鼠制作具有不同白细胞水平的急性心肌缺血病理模型;测定动物模型的血液流变学有关指标.结果与单纯急性心肌缺血组比较,白细胞增多的急性心肌缺血动物血液流变学指标的异常改变幅度更大,两组间多数指标差异显著(P＜0.01或P＜0.05);而白细胞减少的急性心肌缺血动物血液流变学参数的改变幅度小或接近正常,与正常对照组的差异,多无显著性(P＞0.05).结论白细胞数量对急性心肌缺血时血液流变学改变有直接的影响;减少白细胞数量可改善急性心肌缺血性损伤时血液流变学特性.     

Increased numbers of ion channels promoted by an intracellular second messenger

The anomalous rectifier potassium current in Aplysia neurons was examined to determine the immediate cause of an increase in conductance induced by serotonin and mediated by adenosine 3',5'-monophosphate. Voltage-dependent cesium ion block and steady-state current power spectral density were measured under voltage clamp before and after application of serotonin. The amplitude of the anomalous rectifier conductance was increased by adding serotonin, but the shapes of the conductance-voltage curve and the power spectrum were not altered. Calculation of the number of functional channels and of the single-channel conductance from the power spectra indicates that the serotonin-induced increase in conductance resulted from an increase in the number of functional channels, while the single-channel conductance and the open-channel probability were unchanged.     

生根剂促进菊花扦插生根的研究进展

菊花拥有较高的观赏价值,在食品、药剂、保健品和化妆品等行业中也有着广泛应用。随着菊花功能的不断开发,其市场需求逐年增加,而其繁殖速度和成苗品质成了影响菊花产业发展的重要因素之一。扦插苗能保持母株的优良性状且繁殖系数较高,是菊花种苗供给的主要繁殖途径。由于扦插存在着生根时间长、生根数量少等问题,因此提高菊花插穗的生根质量、缩短生根时间对菊花的产业发展具有重要意义。本文对目前使用的促进菊花扦插生根的生根剂进行系统综述,并对其未来发展趋势进行展望,为菊花大规模工厂化育苗提供理论依据。     

Liver organogenesis promoted by endothelial cells prior to vascular function

The embryonic role of endothelial cells and nascent vessels in promoting organogenesis, prior to vascular function, is unclear. We find that early endothelial cells in mouse embryos surround newly specified hepatic endoderm and delimit the mesenchymal domain into which the liver bud grows. In flk-1 mutant embryos, which lack endothelial cells, hepatic specification occurs, but liver morphogenesis fails prior to mesenchyme invasion. We developed an embryo tissue explant system that permits liver bud vasculogenesis and show that in the absence of endothelial cells, or when the latter are inhibited, there is a selective defect in hepatic outgrowth. We conclude that vasculogenic endothelial cells and nascent vessels are critical for the earliest stages of organogenesis, prior to blood vessel function.     

黄芪和杜仲对家兔实验性急性心肌缺血的保护作用

利用静脉注射垂体后叶素建立家兔急性心肌缺血模型,以心电图Ⅱ导联的T波波幅、ST段波幅、PR间期、心率为指标,研究了不同剂量黄芪、杜仲对家兔急性心肌缺血的保护作用。结果表明,在抑制心电图∑T和∑ST增幅方面,黄芪的作用明显优于杜仲,高、低剂量的黄芪作用存在极显著差异(P<0.01),而高、低剂量的杜仲作用差异不显著(P>0.05)。高剂量黄芪的∑T增幅与丹参(阳性对照)比较接近(P>0.05)。低剂量的黄芪抑制心率变缓的作用要大于高剂量的黄芪和丹参(P<0.01),不同剂量的杜仲抑制心率变缓的作用较弱,并存在明显的心律不齐。表明黄芪对家兔急性心肌缺血具有较强的保护作用。     

中医不同治法对大鼠心肌缺血再灌注 损伤后细胞凋亡的影响

〔摘要〕目的观察中医不同治法补气、活血、化痰对大鼠心肌缺血再灌注(( I/R)诱导细胞凋亡及凋亡相关基因 Bcl-2,Bax和氧自由基含量的影响、方法建立大鼠动脉粥样硬化在体心肌缺血再灌注模型,采用原位末端TUNEL 法检测心肌细胞凋亡指数(AI),链酶亲和素一生物素一酶复合物(}BAB(7)免疫组化法检测凋亡相关基因Bcl-2,Bax蛋 白表达,常规方法检测丙二醇(MDA)含量、超氧化物歧化酶(80D)活性、结果与I/R组比较,中医补气、活血、化痰 法均能降低AI,有效清除氧自由基,差异有统计学意义(P<0.01);与I/R组比较,其中活血法和化痰法均能上调 Bcl-2表达、卜调Bax表达,差异有统计学意义(P<0.01),最终达到保护I/R心肌的目的〔结论中医不同治法补 气、活血、化痰可能通过不同途径预防I/R心肌细胞发生凋亡.从而对I/R心肌具有保护作用、     

Fat mobilization in adipose tissue is promoted by adipose triglyceride lipase

Mobilization of fatty acids from triglyceride stores in adipose tissue requires lipolytic enzymes. Dysfunctional lipolysis affects energy homeostasis and may contribute to the pathogenesis of obesity and insulin resistance. Until now, hormone-sensitive lipase (HSL) was the only enzyme known to hydrolyze triglycerides in mammalian adipose tissue. Here, we report that a second enzyme, adipose triglyceride lipase (ATGL), catalyzes the initial step in triglyceride hydrolysis. It is interesting that ATGL contains a "patatin domain" common to plant acyl-hydrolases. ATGL is highly expressed in adipose tissue of mice and humans. It exhibits high substrate specificity for triacylglycerol and is associated with lipid droplets. Inhibition of ATGL markedly decreases total adipose acyl-hydrolase activity. Thus, ATGL and HSL coordinately catabolize stored triglycerides in adipose tissue of mammals.     

Failure of beta-adrenergic receptor blockade to prevent arrhythmias induced by sympathetic nerve stimulation

Cardiac arrhythmias produced by electrical stimulation of the ventrolateral cardiac sympathetic nerve in dogs were not blocked by the combined administration of propranolol and practolol in amounts that completely blocked cardiac beta-adrenergic receptors. Blockade of cardiac alpha-adrenergic receptors, as well as cardiac cholinergic receptors, also had no influence on the arrhythmias. These results suggest that the adrenergic neuroeffector junction is fundamentally different from any hitherto described, differing perhaps in the neurotransmitter involved or in the nature of the receptor.     

以电子设计大赛促进电子技术课程本科教学改革

全国大学生电子设计大赛是由教育部主办的学科竞赛，竞赛内容反映了现代电子技术的应用与发展趋势。本文阐述了如何以电子设计大赛为契机，促进本科电子技术课程教学的内容和实践教学的改革。