Cell cycle synchronization

The yeast Saccharomyces cerevisiae has been an excellent model system for cell cycle studies. Many such studies require cells synchronized in some particular portion of the cell cycle. Here, methods are described for obtaining and examining synchronized cells as they pass through one or more rounds of the cell cycle. The methods are of two types. First, block-and-release methods, where cells are initially synchronized by blocking them at some particular cell cycle stage, then releasing them from the block under conditions suitable for growth, and taking samples at different times after the release, thereby obtaining samples representing different cell cycle stages. The second type of method is elutriation. Centrifugal elutriation can be used to obtain samples of uniformly sized cells, and because cell size is correlated with cell cycle stage, these cells are synchronized with respect to their position in the cycle. Because elutriation is a very different method from block- and-release, it is ideal as a second method of synchronization to ensure that results achieved by block-and-release are not artefactual. Here, block-and-release experiments with the mating pheromone alpha factor, and with the cdc15-2 mutation, are described in detail, as are some elutriation methods.     

Central effects of tetanus and botulinum neurotoxins

Tetanus neurotoxin (TeNT) and botulinum neurotoxins (BoNTs; from A to G) are metalloproteases that act on nerve terminals to prevent exocytosis. They are extensively exploited for the study of cellular physiology. Moreover, BoNTs are also employed in clinical neurology for the treatment of several disorders characterized by hyperexcitability of peripheral nerve terminals. This review summarizes recent studies that have provided a deeper understanding of the mode of action of TeNT and BoNTs. TeNT and BoNTs bind with extreme specificity and are internalized at the neuromuscular junction. We first examine the retrograde transport mechanisms by which TeNT gains access to the central nervous system. We also discuss recent findings indicating that, besides their well known local actions at the neuromuscular junction, BoNTs can also affect central circuits.     

咪唑斯汀治疗慢性荨麻疹30例临床疗效观察

目的：观察咪唑斯汀治疗慢性荨麻疹的疗效观察。方法：慢性荨麻疹患者30例口服咪唑斯汀10mg 1次/d,共两周进行临床观察。结果：治疗30例慢性荨麻疹有效率在第7天和第14天后分别为66.7%和93.3%。治疗过程中不良反应仅为6.7%,且症状轻。结论：咪唑斯汀治疗慢性荨麻疹简便、安全、有效。     

Evaluation for skin sensitization based on published literatures (existing information) of major PRTR designated chemical substances in Japan

Of the 354 substances designated as class I under the Pollutant Release and Transfer Register (PRTR) law in Japan, we reviewed the sensitization data of the selected 144 substances and analyzed it from various aspects comparing human and animal data, determining the relationship between skin sensitization and chemical structure and comparing the various international organizations.Although most of them were expected to be hazardous substances, 49 out of the 144 substances lacked both human and animal sensitization data. Positive substances accounted for 69% and 42% of the substances for which sensitization data were available in the case of humans and animals, respectively.A correlation was observed between the chemical structures of the substances and sensitization, despite the relatively few substances examined in this study and the limited homogeneity of the collected data. In particular, epoxides clearly had sensitizing potentials and more than half of carboxylic esters or dicarboxyl anhydrides, aliphatic aldehydes, and aromatic compounds with at least two hydroxyl groups also had sensitizing potentials.Also, this study clearly demonstrated the lack of consistency across the sensitization assessment criteria adopted by different countries or among those adopted by the same country on the basis of different laws or administrative measures.     

聚电解质复合法载表阿霉素纳米微粒的制备及抗胰腺癌作用的研究

目的合成载表阿霉素纳米微粒（E—ADM-NPs）并检测其相关参数，观察其对人胰腺癌细胞的杀伤作用。方法采用聚电解质复合法合成E-ADM—NPs，动态光散射粒子分析仪测定粒径，分光光度法计算包封率，噻唑蓝（MTT）法观察对胰腺癌细胞的体外杀伤作用。结果E-ADM—NPS的平均粒径（185±23）nm，包封率（762±65）％，体内抑瘤实验表明E-ADM-NPs的疗效优于未包载表阿霉素（unenveloped epirubicin，E-ADM）。结论E-ADM-NPs可有效抑制胰腺癌细胞的生长，是一种安全的新型药物缓释制剂。     

Comparison of a Steady Flow Pump to a Preload Responsive Pulsatile Pump in Left Atrial–to–Aorta Bypass in Canines

A unique preload responsive pulsatile pump was compared to a centrifugal pump in total cardiac support in 25-kg canines (n = 6, each group) in the left atrial-to-aorta mode during 5 h of ventricular fibrillation. With steady flow, there was immediate drop in output from 2.1 +/- 1.0 L/min to 1.4 +/- 0.3 L/min, followed by further reduction to 0.9 +/- 0.2 L/min during 5 h of ventricular fibrillation. With a pulsatile pump, there was no significant reduction from control of 2.4 +/- 0.6 L/min and no decline during 5 h of ventricular fibrillation. With steady flow, systemic vascular resistance (SVR) rose significantly from 1,762 dyne-s-cm-5 immediately on pump to 3,013 dyne-s-cm-5 at 5 h. With physiologic pulsatile flow, significant elevation of SVR did not occur. When stressed, due to diminished left atrial return, the centrifugal pump displayed line chatter and streaks of microbubbles, whereas the pulsatile pump did not. Crystalloid volume replacement with the centrifugal pump was 6.5 +/- 1.9 L, and with the preload responsive pulsatile pump, 5.6 +/- 1.3 L. It is concluded that in the left atrial-to-aorta mode during 5 h of ventricular fibrillation and with comparable volume replacement, total cardiac support of canines is associated with lower SVR with physiologic pulsatile flow and is not accompanied by line chatter and cavitation with this preload responsive pump.     

神经阻滞配合针刀松解治疗脊神经后支卡压所致腰腿痛

目的　探讨脊神经后支卡压所致腰腿痛的致病因素及治疗方式。方法　采用神经阻滞配合针刀松解治疗 30例并与对照组物理疗法 30例比较。结果　治疗组痊愈率 80 % ,总有效率 96 .6 % ;对照组痊愈率36 .6 % ,总有效率 73.3%。治疗组痊愈率明显高于对照组 (P <0 .0 1)。结论　神经阻滞配合针刀松解治疗脊神经后支卡压所致腰腿痛优于物理疗法。     

臀肌挛缩症（弹响髋）松解手术后并发症及处理

105侧（57例患者）臀肌挛缩症Z松解术后有7侧（7例）发生伤口渗血、积血、积液和动脉性出血等并发症，其中伤口渗血、积血和积液各2侧，动脉性出血1侧。通过病历资料总结分析，发现所有术中伤口放置引流的29侧手术后均无发生渗血、积血和积液，提示良好引流在本手术中的重要性。1例动脉性出血患者经重新进入伤口结扎止血后痊愈，其发生可能与局部麻醉药内加用肾上腺素致使手术野血管收缩未能发现出血点有关，提示臀肌挛缩松解手术在局部麻醉下实施时不要在麻药内加用肾上腺素。     

Thyrotropin-releasing hormone has profound presynaptic action on cultured spinal cord neurons

Thyrotropin-releasing hormone (TRH) receptors are widely distributed throughout the nervous system. In particular, both the dorsal and the ventral horn (VH) neurons contain a rich distribution of TRH receptors, and TRH application to these sites has profound physiological effects. Currently the mechanism of action of TRH is not known. We examined the effect of TRH on ventral horn neurons using intracellular and patch-clamp techniques. Our results indicate that TRH application profoundly increases the firing rate of VH cells by decreasing membrane conductance. More importantly, TRH causes a significant increase in frequency and amplitude of postsynaptic potentials. Under voltage-clamp condition, TRH reduces holding current and causes a significant increase in the rate of occurrence and the amplitude of excitatory postsynaptic currents (EPSCs), an effect that lasts for more than 5 minutes. This effect of TRH is not observed in cultured neurons pretreated with tetanus toxin. TRH also fails to alter the characteristics of the EPSCs when it is applied to a region of the cell that is sparsely innervated. These results provide strong evidence that presynaptic mechanisms have a significant role in the excitatory effect of TRH on the VH neurons. Because there is evidence that trophic factors are released from presynaptic terminals, by increasing synaptic activity, TRH can have a trophic influence on the spinal cord neurons. In addition, because there are a significant number of TRH containing neurons within the spinal cord, it is likely that TRH has a major role in information processing within the spinal cord.     

硝酸异山梨酯缓释胶囊的人体药物动力学及相对生物利用度

采用毛细管气相色谱法测定硝酸异山梨酯血药浓度 ,考察了国产及进口硝酸异山梨酯缓释胶囊多剂量口服达稳态过程和稳态药物动力学特征 ,研究硝酸异山梨酯缓释胶囊的人体药物动力学和相对生物利用度。结果表明 ,连续口服硝酸异山梨酯 4 0 mg缓释胶囊三天后 ,体内硝酸异山梨酯血药浓度基本达稳态水平。国产和进口缓释胶囊的稳态药物动力学参数 tmax分别为 4 .33± 0 .4 9和 3.83± 0 .72 h,Cmax分别为 2 4 .78± 8.2 9和 2 4 .4 2± 7.39ng/ ml,AUCss分别为 14 7.5± 18.4和 14 6 .9± 15 .7ng· h· m l- 1 ,波动度 DF分别为 3.5 4± 0 .82和 3.5 2± 0 .81。国产制剂的相对生物利用度为 10 0 .5 %± 8.1% ,经三因素方差分析和双单侧 t检验判定两种制剂具有生物等效性