吗啡对机械通气病人的应用

为获得病人在接受呼吸机期间充分的镇静、良好的耐管并与呼吸机合拍达到满意的治疗效果，对６０例不同年龄的患者在进行呼吸机支持治疗期间，采用平均０４５ｍｇ／（ｋｇｄ）的吗啡量持续微量泵静脉注入，间断辅助安定的方法．用药后连续２ｈ观察血压、心率、呼吸、意识等变化．结果：在用药期间病人血压、心率、呼吸平稳，保持清醒，安静耐管，解决了病人与呼吸机拮抗的矛盾．结果表明：该法在临床上有广泛使用价值     

岛津数字胃肠机IF OVER故障产生的原理及维修

分析了岛津3200数字胃肠机IFOVER故障产生的原因，并结合实际故障现象，具体介绍了排除方法。     

SA-6000全自动血流变仪清洗维护的改进

分析了SA-6000全自动血流变仪在实际使用过程中出现的故障，总结了维护经验，改进了仪器的维护方法。     

Attitudes to social issues in medicine: a comparison of first-year medical students with first-year students in non-medical faculties

The emphasis on academic achievement in medical student selection has given rise to the fear that students entering medicine may comprise a homogeneous group with tendencies towards academic and scientific pursuits rather than humanistic and person-oriented health care. The Attitudes to Social Issues in Medicine (ATSIM) scale was administered to first-year Australian medical students and first-year students in other faculties including students with significantly lower academic performance measured by high school examination scores. The medical student group was found to be less conservative towards general social issues than students enrolled in commerce and science faculties and scored equally with arts students. Greater conservatism was, however, apparent in those areas which most closely affect the doctor's role. Medical students were less positive than other student groups in their attitudes towards increased government control of the medical profession, the contribution of allied health professionals and the importance of social aspects of illness. On attitudes to issues such as prevention and doctor-patient relationships which do not challenge the knowledge base or traditional role and status of the medical profession, however, medical students demonstrate equal or greater concern compared with other student groups.     

呼出气氢测定试验对飞行人员乳糖酶缺乏症的研究

对66名汉族飞行人员进行乳糖呼出气氢测定试验,乳糖吸收不良的发生率为83.3％,其中乳糖不耐受者占34.6％;与一般汉族人群无明显差别。对10名确定为中度以上乳糖吸收不良的飞行人员进行250ml鲜牛奶的试验结果,有50％呼出气氢含量在正常范围,并无一例出现胃肠道症状。提示较长期食用牛奶未能使乳糖酶缺乏状态发生改变,但每日食用适量牛奶属合理营养。     

Mechanical power during maximal treadmill walking and running in young and elderly men

This study determined mechanical power during movements specific to maximal walking and running using a non-motorized treadmill in 38 elderly [69.4 (5.0) years] and 50 young [24.3 (3.4) years] men. The mean mechanical power over a period of time covering six steps, during which the belt velocity peaked and then kept almost plateau, was determined as a performance score in each of maximal walking (WP) and running (RP). In terms of the value relative to body mass, the relative difference between the two age groups was greater for RP (61.7%) than for WP (21.4%) or isometric knee extension (34.1%) and flexion torque (43.8%). In the two groups, WP was significantly (P<0.05) correlated to knee extension (r=0.582 for the elderly and r=0.392 for the young) and flexion torque (r=0.524 for the elderly and r=0.574 for the young). Similarly, RP was also significantly (P<0.05) correlated to knee extension (r=0.627 for the elderly and r=0.478 for the young) and flexion torque (r=0.500 for the elderly and r=0.281 for the young). In these relationships, the WP adjusted statistically by thigh muscle torque was similar in the two age groups. However, the corresponding value for RP was significantly higher in the young than in the elderly. The findings here indicate that: (1) the difference between the young and elderly men in mechanical power is greater during maximal running than maximal walking, and (2) although the thigh muscle torque contributes to the power production during the two maximal exercise modes in the two age groups, the RP is greater in the young than in the elderly regardless of the difference in the thigh muscle torque.     

Dynamic Mechanical Conditioning of Collagen-Gel Blood Vessel Constructs Induces Remodeling In Vitro

Dynamic mechanical conditioning is investigated as a means of improving the mechanical properties of tissue-engineered blood vessel constructs composed of living cells embedded in a collagen-gel scaffold. This approach attempts to elicit a unique response from the embedded cells so as to reorganize their surrounding matrix, thus improving the overall mechanical stability of the constructs. Mechanical conditioning, in the form of cyclic strain, was applied to the tubular constructs at a frequency of 1 Hz for 4 and 8 days. The response to conditioning thus evinced involved increased contraction and mechanical strength, as compared to statically cultured controls. Significant increases in ultimate stress and material modulus were seen over an 8 day culture period. Accompanying morphological changes showed increased circumferential orientation in response to the cyclic stimulus. We conclude that dynamic mechanical conditioning during tissue culture leads to an improvement in the properties of tissue-engineered blood vessel constructs in terms of mechanical strength and histological organization. This concept, in conjunction with a proper biochemical environment, could present a better model for engineering vascular constructs. © 2000 Biomedical Engineering Society. PAC00: 8719Rr, 8714Ee, 8718-h, 8768+z     

Simultaneous electrical and mechanical recording in small isolated perfused arteries

A new method is described for simultaneous measurements of electrical and mechanical activity in an intact segment of a small artery (outside diameter 0·3–0·5 mm). A 7–9 mm segment of rabbit middle-cerebral artery was ligated on a Teflon tube connected to a perfusion circuit. The presence of a plug in the tube, flanked by two orifices, forced the physiological solution to flow in the annular space between the tube and the artery wall. Physiological pressures could thus be attained at low rates of flow, and the pressure, measured upstream, was significantly modifed by the slightest constriction or dilatation of the vascular segment. Electrical recording with glass microelectrodes was performed on a short immobilised portion of the artery. The artery and tube were bathed in a physiological solution at 38°C, but perfusing and incubating solutions did not mix. Spontaneous electrical and mechanical activity of middle cerebral arteries is described, together with modifications induced by vasoactive agents.     

Drawn gelatin films with improved mechanical properties

Chain anisotropic distribution in gelatin films has been obtained by uniaxial stretching at constant relative humidity, followed by air drying and successive cross-linking with glutaraldehyde. The drawn samples have been characterized by mechanical tests, differential scanning calorimetry and scanning electron microscopy. The Young’s modulus, E, and the stress at break, σ_b, increase linearly with the draw ratio and reach values which are about five times those characteristic of undrawn samples. Furthermore, on stretching the alignment of the gelatin strands along the direction of deformation increases while the thickness of the layers decreases significantly. The renaturation level, that is the fraction of gelatin in a collagen-like structure, has been calculated as the ratio between the melting enthalpy of gelatin samples and that of tendon collagen. The results indicate that the improvement of mechanical properties achieved by drawn gelatin is closely related to the renaturation level. The experimental approach utilized to induce segmental orientation in gelatin films, allows to obtain anisotropic materials with improved mechanical properties in the direction of deformation, and can be usefully applied in the preparation of biomaterials.