The effects of introducing or lowering legal per se blood alcohol limits for driving: an international review

In this review evidence on the impact of introducing or lowering legal blood alcohol limits on traffic safety measures is examined. There is substantial variability in the types and rigour of methods used to evaluate these legislative measures, and thus not surprisingly there is variability in the results observed. In most but not all cases where an evaluation of an introduced or lowered legal limit has been conducted, some beneficial effect on traffic safety measures has been reported. These effects are in some cases relatively small, and in other cases may be temporary. In some jurisdictions, lasting reductions in collision rates have been reported. Available evidence suggests that where beneficial effects are observed they are due to general deterrence, and not restricted only to drivers at blood alcohol concentrations (BAC) specifically affected by the legal change.     

Structure-function relationships in the pulmonary arterial tree

Knowledge of the relationship between structure and function of the normal pulmonary arterial tree is necessary for understanding normal pulmonary hemodynamics and the functional consequences of the vascular remodeling that accompanies pulmonary vascular diseases. In an effort to provide a means for relating the measurable vascular geometry and vessel mechanics data to the mean pressure-flow relationship and longitudinal pressure profile, we present a mathematical model of the pulmonary arterial tree. The model is based on the observation that the normal pulmonary arterial tree is a bifurcating tree in which the parent-to-daughter diameter ratios at a bifurcation and vessel distensibility are independent of vessel diameter, and although the actual arterial tree is quite heterogeneous, the diameter of each route, through which the blood flows, tapers from the arterial inlet to essentially the same terminal arteriolar diameter. In the model the average route is represented as a tapered tube through which the blood flow decreases with distance from the inlet because of the diversion of flow at the many bifurcations along the route. The taper and flow diversion are expressed in terms of morphometric parameters obtained using various methods for summarizing morphometric data. To help put the model parameter values in perspective, we applied one such method to morphometric data obtained from perfused dog lungs. Model simulations demonstrate the sensitivity of model pressure-flow relationships to variations in the morphometric parameters. Comparisons of simulations with experimental data also raise questions as to the "hemodynamically" appropriate ways to summarize morphometric data.     

Monitoring fracture site properties with external fixation

An in-vitro system has been devised to monitor the properties of an idealized fracture site immobilized with a Hoffman-Vidal external fixator. A dial gage was used to measure the relative pin displacements under controlled axial loading. The displacement measurements were then used in conjunction with a finite element model to predict the modulus of an idealized fracture site. Five fracture sites made of neoprene disks of different mechanical properties were monitored in order to simulate the increasing modulus of a healing fracture. Good agreement was observed between directly measured mechanical properties of the neoprene and those inferred from the combined finite element and pin displacement tests.     

Perilymphatic fistula and its interest to audiologists

Forty-one patients who had sudden hearing loss associated with spontaneous perilymphatic fistllas were reviewed in this investigation. A history of physical exertion or an upper respiratory infection prior to the onset of hearing loss strongly suggests the presence of spontaneous perilymphatic fistula. However, absence of such a history does not necessarily preclude the possibility of membrane rupture. A great variation in audiologic and vestibular findings was observed. Tinnitus was present for most patients and vertigo or disequilibrium was reported by some. Findings support the need for surgical exploration in patients with sudden hearing loss when a perilymphatic fistula is suspected. Postoperative success in restoring hearing function in cases with perilymphatic fistula is good if the fistula is closed within two weeks after the initial insult. Delay in closure of such fistulas can cause irreversible loss of hearing.     

Free nor-adrenaline and adrenaline excretion in relation to complications in acute myocardial infarction

The authors report on the clinical data, operating technique, postoperative complications, and late results in a series of 31 epidermoid and 21 dermoid cysts of the central nervous system.