Preclinical Pharmacology of Diltiazem

Abstract: The membrane site of action and intracellular effects of diltiazem on heart and blood vessels are briefly discussed and compared to those of other calcium entry blockers, mainly verapamil and nifedipine. Diltiazem seems to have another site of action in the membrane than verapamil and nifedipine. Even if its main action is exerted at the cell membrane level, diltiazem may, at high concentrations, appears to have intracellular effects. Similar to the haemodynamic effects of verapamil and nifedipine, those of diltiazem are determined not only by direct actions on heart and peripheral vessels, but also by sympathetic reflex activity which modulates the direct effects. Two aspects of the myocardial protective action of diltiazem are discussed, the ability of the drug to reduce the frequency of ventricular dysrhythmias associated with ischaemic damage, and the ability to protect the ischaemic myocardium during reperfusion.     

Protection of the heart by Nifedipine cardioplegia during coronary artery surgery A clinical-haemodynamic evaluation

This study was undertaken to evaluate the myocardial preservation obtained by adding a Ca⁺⁺ channel blocker, nifedipine, to cold potassium cardioplegia (4 mcg/Kg/L) in 24 patients undergoing coronary artery surgery. They were randomly divided into a treated (N) and a control (C) group. Significant differences between the two groups were noted in the cardiac arrest time (p<0.001), in the mechanical recovery mode (p<0.01) and in the inotropic support needed (p<0.01). Cardiac index increased significantly in group N but decreased in group C (p<0.01). Peripheral ΔP/Δt and endocardial viability ratio (EVR) decreased in both groups. Coronary sinus and serum CK and CK-MB release were significantly lower in the treated group. ECG ischaemic changes occurred in 8 patients in group C but only in 1 case in group N (p<0.001). Arrhythmias occurred in 3 cases in group C (p<0.05). The incidence of perioperative myocardial infarction was not significant (2 cases in group C). These data suggest that nifedipine can protect the myocardial cell from ischaemic injury without depressing myocardial contractility or AV conduction.     

Radiation protection considerations for endocavitary x ray units

Application of a contact X ray therapy unit* for endocavitary irradiation of selected rectal carcinomas is gaining acceptance as a treatment of choice. The patient is placed on a proctoscopic table in the surgical suite and the anus is anesthetized and dilated to allow insertion of a 3 cm diameter proctoscope designed to admit the X ray tube. The measured half-value layer for 50 kVp X rays filtered by 1.0 mm of aluminium was determined to be 0.65 mm of aluminium. The dose rate at the end of the 4.0 cm source-skin-distance (SSD) cone was measured to be on the order of 1000 rad/minute. Radiation surveys performed for several treatment geometries indicate that exposure rate levels in the environs immediately around the patient can be quite high. Radiation measurements were made for the following locations: where the radiotherapist stands holding the X ray tube; at the side of the patient where the technologist or any supporting personnel might stand; and at the patient's posterior surface in the direction where the anesthesiologist might stand. Radiation levels ranged from 0.001 to 1.0 roentgen (R) per hour and depend primarily on the depth and angle of the X ray tube inserted into the rectum.     

Traumatic Damage Prevented by Contact Lens Wear

ABSTRACT A PMMA contact lens broke in half on the cornea after impact by a small nail. No damage to the eye was detected when the patient was examined three days after the accident.     

从法学和医学双重角度看医疗纠纷与医学保护

在人类科技与文明进程以史无前例的速度推进的今天,人类对医学的认识和自身的健康生存状态有了更深刻的认识,但用法律手段来调整医疗纠纷的范围和程度还有待我们重新认识和定位.人们一方面渴求医疗救助,一方面又怕医疗事故的降临,在"又爱又恨"的心态下寻求着医学和法律的救济,人们要么单一的从法律角度看待医疗纠纷,要么单一的从医学角度看待医疗纠纷,但医学和法律都不是万能的,如何既考虑保护单个患者的合法权益,又考虑到作为特殊行业的医疗机构的公益性、医学的风险性、医疗技术的发展乃至全社会的共同利益,是今天法学界和医学界应该共同探讨的问题.不管怎么说,"无论法律多么有力以及我们多么希望法律不断强大,适可而止仍是法律的美德".     

血小板因子4的辐射防护作用

目的：研究血小板因子4(PF4)对全身照射小鼠的辐射防护作用．方法：实验分为两部分．第一部分．小鼠随机分为4组，第二部分分为3组，小鼠总数为70只．照射组和PF4保护组接受7．5Gy^60Coγ射线全身照射．观察小鼠30d存活率和存活天数．用自动细胞计数仪计数外周血细胞．测定骨髓单个核细胞数和CFU-GM的形成能力．用紫外分光光度计测定骨髓细胞内DNA的含量．用流式细胞仪测定细胞周期的变化．测定小鼠的体、脾脏和胸腺的质量．结果：PF4能够增加照射小鼠的生存率．增加骨髓细胞内．DNA的含量及骨髓单个核细胞数，提高CFU-GM的形成能力，降低造血细胞的增殖指数，增加照射小鼠的脾体比和胸体比．结论：PF4在小鼠全身照射前使用能够减少骨髓和淋巴组织的辐射损伤．可作为辐射防护剂．     

温血停搏液诱导及末次灌注心肌的保护作用

将温血停搏液诱导及末次灌注应用于临床２０例成人人工瓣膜替换术术中心肌保护。２０例均恢复顺利，无１例术后早期死亡。诱导心脏停搏较快，均于温血停搏液２分钟诱导完毕前停搏。自动复跳率及房颤转窦率均高。术中心肌三磷酸腺苷测定发现此法能保存更多的心肌能量物质。术中及术后血清中肌酸磷酸激酶测定见其术后升高低于对照组，且恢复也较快，提示心肌细胞损伤较轻。本法易于施行。实验及临床均证实其对术中缺血心肌保护的效果优于传统的冷钾晶体停搏液，有推广前景。     

1，6－二磷酸果糖和卡托普利抗心肌缺血和再灌注损伤的实验研究

在离体大鼠心脏灌流模型上，探讨了心肌缺血再灌注损伤机制，同时比较了１，６－二磷酸果糖（ＦＤＰ）和卡托普利（ＣＰ）对心肌缺血再灌注损伤的保护作用。结果表明：（１）ＦＤＰ和ＣＰ对缺血心肌和再灌注损伤均有保护效果，但ＦＤＰ仅在缺氧开始给药，才能充分发挥其效应；二者联合用药对心肌保护有更好的效果。（２）缺血损伤的严重程度决定着再灌注损伤的程度，改善缺氧影响是防止再灌注损伤的先决条件。     

Cardiocirculatory arrest with hypothermia. Experimental study

Direct surgical attack on intracranial malformations of great complexity may be facilitated by complete cardiocirculatory arrest under hypothermia. To improve the technical aspects of this procedure and to determine the optimum depth of hypothermia, the duration of arrest that can be tolerated, and the role of barbiturate brain protection, we conducted an experimental study on 11 baboons. Arrest lasted for 45 or 90 minutes at a brain temperature of 12°C. The animals were assessed by clinical, neuroradiological and necropsy examination. All 4 animals subjected to 45 minutes arrest made a good clinical recovery while 3 of the 7 subjected to 90 minutes arrest presented thromboembolic complications. Strict heparinization in the last 2 animals solved these problems. The findings of this study may help to make the procedure safer for clinical use.

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Sommario Il trattamento chirurgico diretto di malformazioni vascolari intracraniche di grande complessità può essere facilitato dall'impiego dell'arresto cardio-circolatorio completo in ipotermia. Allo scopo di perfezionare gli aspetti tecnici di questa metodica e di definire il grado ottimale di ipotermia, la durata di arresto tollerabile e il ruolo della neuroprotezione barbiturica, è stato eseguito uno studio sperimeniale su 11 babbuini. L'arresto è stato protratto per 45 e 90 minuti, ad una temperatura cerebrale di 12 gradi C. Gli animali sono stati valutati con esame clinico, neuroradiologico e patologico. Quelli sottoposti ad arresto di 45 minuti hanno presentato un ottimo recupero clinico; nel secondo gruppo, 3 su 7 hanno presentato complicanze di tipo tromboembolico. L'adozione di una eparinizzazione rigorosa ha permesso di eliminare tali problemi negli ultimi 2 babbuini. Le osservazioni ricavate da questo studio potranno risultare preziose in vista di una applicazione più sicura della metodica in campo clinico.

     

透视美军"部队健康全面保护"构想

“部队健康全面保护”构想是美军军事医学的纲领性文件，是系列的健康保护规划，是美军“2010年联合构想”的卫生勤务子构想。其核心思想是强健促进、伤病预防、战救勤务并重，全面保持、恢复和提高军人健康。该构想对美军军事医学产生了重要影响，对我军也有重要启示。