大鼠纹状体边缘区神经元中乙酰胆碱激活的离子通道特性

用细胞贴附式膜片钳技术研究了急性分离的新生SD大鼠纹状体边缘区神经元中乙酰胆碱激活的离子通道的特性。发现通道有25PS和60PS两种电导状态,25PS通道为主要类型,因此,本文主要报道25PS通道的特性。ACh激活的单通道电流为快速内向电流,随着超极化程度增加而增加,反转电位约为0mV。通道开放具单个开放和簇状开放,其开放时间均可权指数拟和,单个开放时间常数为0．29ms和1.84ms,簇状开放时间常数为1．96ms和18.24ms。平均关闭时间也可双指数拟和,两个时间常数为1．70ms和54．00ms。通道开放概率为0．012,未表现出电压依赖性。提示纹状体边缘区神经元上存在乙酸胆碱受体离子通道。根据特性证实为烟碱型离子通道。     

Decreased incidence of arterial thrombosis using heparin-bonded intraaortic balloons

BACKGROUND: This experimental study sought to determine whether heparin-bonding of intraaortic balloons (IAB) would decrease the incidence of arterial thrombosis in the absence of systemic heparinization. METHODS: In 25 adult pigs, a 9F, 40-mL IAB was inserted into the femoral artery and positioned just below the takeoff of the left subclavian artery for 9 hours. Five animals received systemic heparin, 10 animals had no heparin, and another 10 animals received no heparin but the IAB was heparin-bonded (Duraflo II). Thrombus formation was assessed using a numerical scoring system (0 = no thrombosis to 3 = thrombus >5 cm or evidence of luminal compromise). RESULTS: Animals receiving heparin and heparin-bonded IAB had no thrombus formation around the IAB (mean +/- SE; 0 +/- 0.00 heparin versus 1.55 +/- 0.29 no heparin versus 0 +/- 0.00 heparin-bonded; p < 0.005), at the insertion site (0 +/- 0.00 heparin versus 1.55 +/- 0.29 no heparin versus 0 +/- 0.0 heparin-bonded; p < 0.005), and in the distal femoral artery (0 +/- 0.00 heparin versus 2.00 +/- 0.23 no heparin versus 0 +/- 0.00 heparin-bonded; p < 0.005). CONCLUSIONS: Heparin-bonding of the IAB significantly decreases thrombus formation in the absence of systemic heparinization.     

Favorable impact of stents after emergent coronary artery bypass for failed angioplasty

BACKGROUND: This study was undertaken to determine the impact of the use and availability of coronary stents on outcomes in patients requiring emergent coronary artery bypass graft (CABG) surgery following a failed percutaneous transluminal coronary angioplasty (PTCA). METHODS: Patients were divided into two groups based on the year of their CABG for a failed PTCA and the availability of stents: group 1, 1992 to 1994, stents not available (n = 34); and group 2, 1995 to 1997, stents available (n = 26). RESULTS: CABG patients in the group where stents were not available were more likely to have had an abrupt coronary occlusion (26 of 34 versus 3 of 26; p < 0.0001) and less likely to have had a dissection (8 of 34 versus 23 of 26; p < 0.0001) as their indication for emergent CABG. Patients in the stent era had a lower incidence of perioperative myocardial infarction (5 of 26 versus 17 of 34; p < 0.01) and a decreased mortality rate (0 of 26 versus 6 of 34; p < 0.03). In the 9 patients where stents were employed, patency of the lumen was restored in 8 patients and there was only 1 myocardial infarction. CONCLUSIONS: Stents have had a favorable impact on patients requiring an emergent CABG following a failed PTCA.     

Regulation of the angiotensin type-1 receptor by antisense oligonucleotides occurs through an RNase H-type mechanism

Multiple, diverse sites in the coding region of the angiotensin type-1 receptor mRNA were targeted with 2'-deoxyribonucleotide antisense oligonucleotides (ONs). The uptake of 1 microM concentration of these ONs into Chinese hamster ovary cells was facilitated by the use of cationic liposomes. The antisense sequences reduced binding of 125I-angiotensin II by 57-73%, while mismatch ONs and reverse sequence ONs produced little reduction in receptor binding. These reductions in AT1 receptor binding were accompanied by comparable decreases in AT1 receptor mRNA levels. Furthermore, mRNA cleavage fragments corresponding in size to 3'-cleavage fragments were observed with two of the antisense ONs, consistent with the involvement of an RNase H-type enzyme. When 2'-methoxyribonucleotide analogs of these same sequences were tested, AT1 receptor mRNA levels were unchanged even though small reductions in AngII binding were observed. Antisense effects seen with these 2'-methoxyribonucleotide sequences may have arisen through a translational arrest mechanism. Direct comparisons between 2'-deoxyribonucleotide analogs and their 2'-methoxyribonucleotide counterparts show that antisense effects are significantly larger when they are mediated through an RNase H-type mechanism. 2'-methoxyribonucleotide sequences were most effective when they were directed against the translation initiation codon.     

病人图书馆是医院图书服务的新领域

建立病人图书馆,以“图书治疗”、“图书护理”为患者提供服务,是现代医学模式转变的需要。国外病人图书馆的发展对病人治疗康复已起到了积极的作用。我国应根据国情建立不同模式的病人图书馆,为患者提供多种多样的服务。     

Protection from oxidant injury by sodium-dependent GSH uptake in retinal Müller cells.

Glutathione (GSH) is known to play an important role in regulating oxidative damage to cells. The present study was initiated to examine the effect of exogenous GSH on oxidative injury in a retinal Müller cell line and to characterize GSH transport in these cells. Rat Müller cells (rMC-1) were incubated with varying concentrations of t-butylhydroperoxide (t-BHP) to induce oxidative stress, and cell viability was measured after addition of GSH. In other studies, kinetics of GSH uptake and Na+-dependency were examined by incubating cells with35S-GSH in Na+-containing and Na+-free buffers. GSH uptake was studied with GSH at concentrations varying from 0. 05-10 m m in NaCl buffer. In the presence of sodium, extracellular GSH provided protection against t-BHP-induced oxidant injury to rMC-1 cells; in contrast, the amino acid precursors of GSH did not have any effect on cell viability. GSH was taken up by rMC-1 cells in a concentration- and sodium-dependent manner. Kinetic studies revealed both a high affinity (Km approximately 0.31 m m) and low affinity Km( approximately 4.2 m m) component. Furthermore, GSH depletion had no significant effect on the rate of GSH uptake. The results show that physiological concentrations of GSH can protect Müller cells from oxidative injury. Both Na+-dependent and Na+-independent transport systems for GSH exist in Müller cells, and the Na+-dependent GSH transporter may be involved in the protective role of GSH.     

高频透热撕囊法在白内障手术中的应用

目的:评价在白内障手术中使用高频透热撕囊仪作连续环形撕囊的效果。方法:在30例(34眼)患者进行白内障囊外摘出联合后房型人工晶体植入术中,先向前房注入透明质酸钠,然后使用高频透热撕囊仪作晶体连续环形撕囊术。结果:有3眼术中出现小的晶体前囊放射状撕裂,所有病例术后角膜无水肿,无其他术后合并症,术后一周31眼矫正视力≥0.5,占91.2％。结论:此法操作简便,易于掌握,是一个安全有效的连续环形撕囊的方法。尤其适用于过熟期白内障,儿童先天性白内障和外伤性白内障的截囊。眼科学报1999;15:121—123。     

后巩膜加固术对视网膜振荡电位的影响

目的　为了更进一步地了解后巩膜加固术治疗高度进行性近视的疗效和机理。方法　采用日本产Ｎｅｕｒｏｐａｃｋ Ｆｏｕｒ ４１０４ Ｋ 电生理仪,对２６ 例５２ 眼高度进行性近视行后巩膜加固术前、术后视网膜振荡电位进行定量分析。结果　术前、术后振荡电位总振幅经统计学处理有非常显著性差异,波的潜伏期无显著性差异。结论　本文认为后巩膜加固术可改善视网膜血液循环,并对机理进行了探讨     

国产生长激素治疗生长激素缺乏症的疗效观察

了解国产人生长激素（ｈＧＨ）的治疗效果。方法：对１５例未经生长激素治疗的生长激素缺乏症（ＧＨＤ）病人（均经精氨酸和可乐宁两项生长激素激发试验明确诊断,生长激素峰值均小于 １０ μｇ／Ｌ）应用国产分泌型基因重组人生长激素（ｒｈＧＨ）进行治疗,剂量为０．１ｕ／（ｋｇ·ｄ）睡前脐周皮下注射,治疗时间６个月。结果：１５例ＧＨＤ病人６个月身高平均增长（６．３４±０．９４）ｃｍ,生长速度由治疗前的（３．３３±０．４９）ｃｍ／年增加到治疗后的（１２．６８±１．８６）ｃｍ／年。结论：国产人生长激素治疗效果达到国外同类产品水平,而价格仅为进口产品的１／６左右。可安全有效地用于治疗ＧＨＤ身材矮小病人。     

踝部骨折有关问题的探讨

本文报导125例髁部骨折，其中52例严重骨折随访8个月至5年2个月。根据本组资料，作者对下胫腓关节损伤的诊断和处理、闭合治疗中骨折再移位问题以及50岁以上患者踝部骨折的治疗特点作了讨论。