全髋关节置换术中钴-铬股骨头不同磨损部位的摩擦学特性

 通过使用原子力显微镜检查(atomic force microscopy,AFM)计算表面粗糙度和摩擦系数的方法,对工程和生物材料的摩擦学特性进行研究。尽管之前的大量研究对全髋关节置换术中不同承重材料的摩擦系数进行了报告,但却没有关于全髋关节置换术术中轴承材料的表面粗糙度和摩擦系数的关系的报道。此外,钴-铬股骨头不同磨损部位的摩擦学特性尚不明确。因此,本研究对全髋关节置换术后 10年钴-铬股骨头发生严重磨损及轻微磨损部位的表面粗糙度、摩擦系数和硬度之间的关系进行研究。钴-铬股骨头的平均维氏硬度为(380.7±11.3) HV。在 AFM扫描的 25滋m伊25滋m面积内,严重磨损和轻微磨损部位的摩擦系数分别为 0.229±0.054和 0.243±0.059,两者差异无统计学意义(P=0.449)。严重磨损部位的表面粗糙度[Rq=(96.5±26.2) nm]与轻微磨损部位[Rq=(17.7±4.2) nm]的差异有统计学意义(P <0.0001)。本研究结果显示院钴-铬股骨头的摩擦特性与其表面粗糙度没有明显关系,为金属植入材料表面特性的改善提供了依据。     

MEASUREMENT OF ROOT CANAL LENGTH – USE OF AN ELECTROMETRIC DEVICE

The measurement of root canal length is a pre-requisite for successful pulpectomy. The conventional manual and radiographic methods are not very accurate. In the present study, odontometer was used [Group B) to assess its efficacy over the conventional methods (Group A) for recording root canal length. In group A, 36 teeth were treated with pulpectomy while in group B, 51 teeth were managed by the same treatment. It was observed that post operative complications in group B were significantly less (p < 0.05). The odontometer proved to be an excellent device for rapid and accurate measurement of root canal length.KEY WORDS: Pulpectomy, Root canal length, Odontometer     

COMPARING THE EFFICACY OF CISAPRIDE AND RANITIDINE IN OESOPHAGITIS: A DOUBLE-BLIND,PARALLEL GROUP STUDY IN GENERAL PRACTICE

SUMMARY Patients with endoscopically confirmed oesophagitis (n=49) were treated for 8 weeks with either cisapride (10 mg four times a day) or ranitidine (150 mg twice a day) in a double-blind study in general practice. Mean overall symptom scores fell from 10.8 to 4.5 in the cisapride group and from 9.9 to 4.4 in the ranitidine group over the course of the study. The proportion of patients reporting improvements in individual symptoms in the two treatment groups (cisapride and ranitidine respectively) were: heartburn, 66% and 55%; acid regurgitation, 53% and 47%; epigastric pain, 60% and 52%; satiety, 57% and 47%; bloating, 69% and 71%; belching, 65% and 72%; nausea, 62% and 85%; vomiting, 77% and 66%; poor appetite, 50% and 75%. Improvement in the endoscopic grade of oesophagitis was observed in 66% of patients receiving cisapride and 63% of those receiving ranitidine. It was concluded that cisapride is as effective as ranitidine in relieving the symptoms of oesophagitis and in healing oesophageal erosions.     

Acute hemodynamic effects of combined inhibition of neutral endopeptidase and angiotensin converting enzyme in spontaneously hypertensive rats

Summary— Neutral endopeptidase inhibitors (NEPI) potentiate the hypotensive effect of converting enzyme inhibitors (CEI) in conscious spontaneously hypertensive rats (SHR) but the mechanism of this potentiation remains unknown. The present study assesses the hemodynamic effects of a CEI (enalaprilat 1 mg/kg; n = 9), a NEPI (retrothiorphan 25 mg/kg + 25 mg/kg/h; n = 9) and the combination (CEI + NEPI; n = 9) versus a control group ( n = 9) in anesthetized spontaneously hypertensive rats. CEI alone induced a significant hypotensive effect due to a decrease (–35.1%) in total peripheral resistance (TPR), with no significant increase in cardiac output (CO). NEPI alone had a slight hypotensive effect due to a small decrease in CO. CEI + NEPI decreased the mean arterial pressure to the same extent (–26.7%) as the CEI-induced hypotensive effect, decreased TPR (–44.4%) and induced an increase in CO (+ 38.2%) with an increase in heart rate. In summary, NEPI combined with CEI induces large decreases in blood pressure and in TPR which do not significantly differ from the CEI-induced effects. It also induces increases in heart rate and in cardiac output in anesthetized SHR.     

Diatrizoate enemas: facts and fallacies of colonic toxicity

Rats were given enemas of Gastrografin in two strengths, Renografin--76, and Tween--80 in a 10% dilution. There were no deleterious effects on the colons with these media used in volumes to fill the colon. Severe changes resulted from volumes which produced overdistention.     

Workplace conditions predict the risk of premature death and functional dependence after retirement—results of a gerontological follow-up study in Germany

Between 1983 and 1985, 595 employees who were entering retirement in East Germany were given a medical examination and asked to assess their workplace conditions. Ten years later, we examined whether occupational predictors were associated with death and functional dependence among the study participants and assessed how the surviving pensioners coped with activities and instrumental activities of daily living. We assigned the occupational factors reported between 1983 and 1985 to two scales: demands and resources. Multiple logistic regression analyses were carried out to examine the association of occupational and medical predictors with the outcome variables death and functional dependence. Workplace resources but not demands were significantly associated with a reduced chance of death in women, independent of medical diagnoses. For men neither of these associations were verified. Concerning functional dependence individual items such as ‘control over work content’ (for both sexes) significantly reduced the risk of developing ADL-dependence. The associations remained stable after medical diagnoses were additionally taken into consideration. The results of our study highlight the influence of occupational factors beyond working life and support the importance of starting geriatric health promotion before retirement age. Public Health (2001) 115, 345–349.