Design of a Centrifugal Blood Pump with Magnetic Suspension

Abstract: A new concept blood pump, whose impeller is suspended by permanent magnets and a mechanical pivot without seals or ball bearings, is presented in this paper. The primary aim of the blood pump is an application to implantable artificial hearts. The prototype model is of a centrifugal type with a four-vaned semiopen impeller 50 mm in diameter. Since this mechanism has no seals or ball bearings, flow stagnation or heat generation that might cause blood cell denaturation is expected to be small. The results of performance testing for the prototype model 2 were satisfactory regarding pump head and efficiency. The radial-suspension magnets and the magnetic coupling were stable. As a result, the present mechanism has been verified to be a candidate applicable to implantable artificial hearts.     

Clinical Evaluation of a New Type of Centrifugal Pump

Abstract: The major problems with existing centrifugal pumps are leakage, mechanical trauma, and thrombus formation. In consideration of these problems, a new compact centrifugal pump system was developed. The purpose of this study was to evaluate the new centrifugal pump system clinically. Ten patients underwent open heart surgery with a centrifugal pump or a roller pump. During surgery, hemodynamic and hematological data were obtained. A pulsatile assist device in the pump circuit was used in patients with severe heart disease. There was neither operative death nor hospital mortality, and there was no difference with regard to hemodynamic data between the two groups. The centrifugal pump group, however, had significantly lower hemolysis, especially during prolonged cardiopulmonary bypass. This centrifugal pump could also create sufficient pulsatile flow with a pulsatile assist device. Postoperative macroscopic and microscopic findings demonstrated the smooth surface of the pump without thrombus formation. This centrifugal pump system might be useful for prolonged cardiopulmonary bypass.     

ACARDIAC TWIN FETUS WITH SEVERE HYDROPS FETALIS AND BILATERAL TALIPES VARUS DEFORMITY

Twin reversed-arterial-perfusion syndrome (TRAPS) is a rare complication of monochorionic twin pregnancies. TRAPS is characterized by the hemodynamic dependence of a “recipient” twin from a “pump” twin. The “recipient” twin exhibits lethal abnormalities, such as acardia and acephaly. Circulatory failure of the normal twin derives from the existence of arterio-arterial and veno-venous anastomoses within the placenta that allow retrograde perfusion of the acardiac twin by blood coming from the normal twin. Acardiac twinning is the most extreme manifestation of the twin-twin transfusion syndrome. This occurs in 1 in 100 monozygotic twin pregnancies and 1 in 35,000 births. We report a case of diamnionic monochorionic female twins in which the acardiac twin demonstrated severe hydrops fetalis and bilateral talipes varus deformity. Cesarean section was performed on a 27-year-old hypertensive gravida 2, para 1 mother for fetal indications at 32 6/7 weeks gestation. The acardiac fetus had a two-vessel umbilical cord measuring 43.5 cm in length and 0.8 cm in diameter. The proximal end inserted into the root of the normal twin's umbilical cord in an acute angle forming a “v” close to the placental disc. Structures rostral to the thorax were absent except for a round mass of flesh with three small buds in place of the head and neck, and bilateral upper extremities. Only the kidneys, right adrenal, small and large intestine, and rudimentary urinary bladder were present. Both feet demonstrated talipes varus deformity. The fetus was severely hydropic. The subcutaneous fat measured 4.5 cm in maximum thickness. The normal twin had a protracted course complicated with respiratory distress syndrome, moderate secundum atrial septal defect with left to right shunt, and thrombocytopenia of prematurity. The baby was eventually discharged after approximately 1 month. At the time of this report, 5 months postpartum, the neonate is growing and developing normally. To our knowledge, this is the first report of severe hydrops fetalis and talipes varus deformity in an acardiac twin.     

Modification of the Na,K-pump of glial cells within cobalt-induced epileptogenic cortex of rat

The characteristics of a glial Na⁺,K⁺-pump dependent on extracellular K⁺ within epileptogenic cortex were studied electrophysiologically, biochemically and histochemically in vitro using slices from cobalt-induced epileptogenic cortex of rat. When the extracellular K⁺ concentration ([K⁺]_o) was varied between 4 and 40 mM, the mean slope of membrane potential plotted against [K⁺]_o was about 57 mV in glia from the normal cortex (tissue A) and about 44 mV in glia from the epileptogenic cortex (tissue B); whereas no significant difference in the resting membrane potential of these tissues was observed. In glia from tissue B, a marked transient hyperpolarization above control level was caused by replacement of elevated [K⁺]_o with the normal medium. Ouabain abolished these phenomena observed in glia from tissue B, but had no effect on the membrane potential during normal [K⁺]_o. Reduction of extracellular Na⁺, Ca²⁺ and Cl⁻ did not significantly affect the membrane potential of glia from either tissue. In tissue A, the cells marked by intracellular injection of horseradish peroxidase after intracellular recording were protoplasmic astrocytes; in tissue B, fibrous astrocytes with abnormal processes predominated. K⁺-dependent stimulation of Na⁺,K⁺-ATPase activity of the astrocyte-enriched fraction and its membrane preparation from tissue B was much larger than that from tissue A. A certain amount of the reaction product of K⁺-pNPPase activity was seen on glial plasma membrane within tissue B but not on that from tissue A. The above findings suggest that a glial Na⁺,K⁺-pump within actively firing epileptogenic cortex may be modified to increase in its activity.     

非体外循环冠状动脉搭桥术早期疗效的探讨

目的：探讨非体外循环心脏不停跳冠状动脉搭桥术的安全性和早期临床效果。方法：自2000年7月至2002年3月51例冠心病患接受冠状动脉搭桥手术，按手术方式分为非体外循环组（n=21）和传统体外循环组（n=30)。将两组病人的术前临床资料，手术方式，术后并发症和疗效等进行对比分析。结果：两组术前临床资料无明显差异。非体外循环组手术时间，术后出血输血量，呼吸机辅助时间显少于体外循环组，并且术后心律失常的发生率明显降低（P均＜0．05），其他重要器官的并发症发生率亦低于体外循环组。两组平均随访9．6个月，心绞痛均消失，心功能改善，活动量明显增加。结论：非体外循环冠状动脉搭桥术是安全可行的，并发症少，近期疗效满意。     

喂饲泵应用的临床观察及护理

目的 探讨用喂饲泵行肠内营养摄入的临床应用价值。方法 实验组30例采用喂饲泵控制肠内营养液的滴入速度，对照组采用传统方法，用20ml或50ml注射器灌注营养液，观察两组并发症的发生情况，所得量化指标进行卡方检验。结果实验组其返流、呕吐、腹胀、吸入性肺炎的发生率明显低于对照组。结论应用喂饲泵行肠内营养的摄入，可有效预防并发症的发生。     

国产圣唐型胰岛素泵的研制及临床应用

胰岛素泵是胰岛素强化治疗的理想手段。为此，我们采用了双微处理器进行互测和自测，共同控制电机使精密丝杆丝母推动注射器输注胰岛素药液的原理研制了国产胰岛素泵；本仪器具有输注精度高、可靠性大、中文操作界面、使用方便等特点。临床观察证明用此国产胰岛素泵治疗糖尿病具有安全、稳定、效果好的优点。     

紫外分光光度法测定对乙酰氨基酚泡腾片含量

本文用紫外分光光度法在２５７±１ｎｍ波长处测定对乙酰氨基酚泡腾片的含量，其浓度与吸收度的线性关系良好，相关系数ｒ＝０．９９９９８。平均回收率为９９．９４％，变异系数为０．２０％。本法简便、快速、结果准确。     

尼莫地平片溶出度的研究

采用转篮法对尼莫地平国产市售片，进口片和自制片在不同介质、不同转速和ＰＨ条件下的溶出度进行测试。结果表明，介质对尼莫地平溶出具有很大的影响，而最佳测定方法是以０．１％的十二烷基硫酸钠水溶液为介质，转速１５０ｒ／ｍｉｎ。     

Gastro-oesophageal reflux disease: Medical or surgical treatment? Report of an interactive workshop

Gastroesophageal reflux disease (GERD) is the most common disease of the upper gastrointestinal tract. With the introduction of proton pump inhibitors medical treatment of GERD has been significantly improved. However, the development of laparoscopic antireflux surgery resulted in an increasing interest of surgeons in this disease. An interactive meeting was organized in order to develop an agreement between gastoenterologists and surgeons regarding therapeutic decisions and this is the main topic of this paper.