Improved osteogenic vector for non-viral gene therapy.

Therapeutic compensation of deficient bone regeneration is a challenging task and a topic of on-going search for novel treatment strategies. One promising approach for improvement involves non-viral gene delivery using the bone morphogenetic protein-2 (BMP-2) gene to provide transient, local and sustained expression of the growth factor. However, since efficiency of non-viral gene delivery is low, this study focused on the improvement of a BMP-2 gene expression system, aiming for compensation of poor transfection efficiency. First, the native BMP-2 gene sequence was modified by codon optimisation and altered by inserting a highly truncated artificial intron (96 bp). Transfection of multiple cell lines and rat adipose-derived mesenchymal stem cells with plasmids harbouring the improved BMP-2 sequence led to a several fold increased expression rate and subsequent osteogenic differentiation. Additionally, comparing expression kinetics of elongation factor 1 alpha (EF1α) promoter with a state of the art CMV promoter revealed significantly higher BMP-2 expression when under the influence of the EF1α promoter. Results obtained by quantification of bone markers as well as osteogenic assays showed reduced sensitivity to promoter silencing effects of the EF1α promoter in rat adipose-derived mesenchymal stem cells. Finally, screening of several protein secretion signals using either luciferase or BMP-2 as reporter protein revealed no superior candidates for potential replacement of the native BMP-2 secretion signal. Taken together, by enhancing the exogenous BMP-2 expression system, low transfection efficiencies in therapeutic applications can be compensated, making safe non-viral systems even more suitable for tissue regeneration approaches.

Traumatic dental injuries and Alpine skiing.

The purpose of this study was to determine the occurrence and type of traumatic dental injuries after maxillofacial injuries as a result of Alpine skiing. During an 8-year period (from January 1991 to December 1998) 7600 patients with facial injuries were registered at the Department of Oral and Maxillofacial Surgery, University of Innsbruck, Austria. Of 784 patients with skiing-related facial injuries (524 males, 260 females) 326 (41.6%) sustained injuries to 639 teeth. The age groups predominantly affected were between 7 and 32 years. Luxation injuries occurred in 338 (53%) teeth, fractures accounted for 270 tooth injuries (42%), and only 35 (5%) were lost at the place of the accident. Of skiers with traumatic dental injuries 58% had concomitant soft tissue injuries, while 23.3% had associated facial bone fractures. The most common causes of injury were falls in 42% (329 patients) and collisions with other persons in 24.1% (189 patients). Being hit by one's own sports equipment (11%) was the third most common cause. Collisions with obstacles accounted for 9% and lift accidents for 5.6% of injuries. The probability of suffering dentoalveolar trauma during skiing varied depending on the injury mechanism. There was a 2-fold risk for dentoalveolar trauma when colliding with objects, a 3.5-fold risk when hit by one's own equipment and a 8.5-fold risk during lift accidents. Dental injuries occurred in about 2% of all injured skiers. Dental health professionals should be aware of the high incidence and the distribution of dental trauma and facial injuries caused by skiing.

[Dental prosthesis--residual alcohol content?]. / Die Zahnprothese--ein Alkoholdepot?

The possible influence of complete or partial dental prosthesis when detecting breath alcohol by means of the breath alcohol analyser "Alcomat" was investigated in a study. During the study, volunteers were asked to rinse their mouths with different types of alcohol such as beer, wine, schnapps and sweets containing alcohol. No influence of the dental prosthesis on the results could be detected. A dental prosthesis neither prolongs the duration of residual alcohol detection, nor does it affect the period of false positive breath alcohol detection. In individual cases the waiting period of 15 minutes between the last alcohol consumption and the breath alcohol test--as legally enforced in Austria--has proved to be too short.

Cardiovascular distortion in experimental nonpenetrating chest impacts.

High-speed cineradiography and flash radiography were used to determine cardiac distortion and the motion of the heart within the thorax following nonpenetrating chest impact. Maximum ventricular distortion occurred approximately 3 ms after impact which was also the time of maximum chest wall displacement. Between +3 ms and +10 ms the heart moved posteriorly and regained much of its initial shape. Maximal posterior displacement of the body of the heart occurred at approximately +10 ms. Three-dimensional reconstruction showed that the heart moved caudally and to the right, with little rotation. The aortic arch moved cranially with consequent stretching of the thoracic aorta.

The biomechanical response of the thorax to nonpenetrating impact with particular reference to cardiac injuries.

Sternal injury, gross cardiac pathology, and cardiac dysrhythmias following nonpenetrating impact by a variety of impactors to the sternum of experimental animals are described. The biomechanical response of the chest wall to the impact and the associated transient pressure changes within the heart are presented, and a correlation between injury severity and chest wall displacement is demonstrated. A simple model is then developed to predict chest wall displacement if the mass, velocity, and dimensions of an impactor are known. The model demonstrates the dependence of chest-wall displacement upon preimpact kinetic energy, impact diameter, and target size.