Summary.A method for investigating stretching of small blood vessels is presented. Stress and strain properties of the isolated parasagittal bridging veins were studied. These veins were stressed along their long axis and torn apart at various constant strainrates. The bridging vein's strain capacity was found to be dependent on strain rate, maximal strain was markedly reduced as the rate was increased. The maximal tension in the veins increases as the time to tearing decreases. The tearing tension was shown to be lower for bridging veins as compared to larger veins (femoral, popliteal, inferior vena cava). Zusammen]assung. Eine Methode zur Untersuchung der Reil~festigkei~ bei Streckung kleinerBlutgef~l~e wird beschrieben. Die Spannungs-und Dehnungseigenschaften isolierter parasagittaler Brfickenvenen (Vv. cerebri sup.) wurden untersucht. Die Venen wurden in ihrer L~ngsrichtung belastet und rissen bei verschiedenen konstanten Dehnungsgeschwindigkeiten. Das maximale DehnungsvermSgen wurde bei grSl~erer Dehnungsgeschwindigkeit stark herabgesetzt. Die maximale Spannung in den Briickenvenen stieg, wenn die Zeit bis zum Abril~ kiirzer war. Die Zerreil~spannung war ~iir Brfickenvenen geringer als fiir grSl~ere Venen (V. femoralis, V. poplitea, V. cava inf.). Key words: Traumatology, disruption of bridging veins --Bridging veins, disruption.The superior cerebral veins together with the surrounding connective tissue (Pacchionian granulations) and the sometimes accompanying arteries comprise the only connections between the brain's mantel edge and the rigid dura. It is well known that these bridging veins can rupture as a result of trauma to the head. It is assumed that as a result of angular acceleration of the head the bridging veins can rupture into the subdural space (Fig. 1), intraarachnoidally or subcortically, which would thus cause subdural, subarachnoidal or intracerebral bleeding, respectively. These injuries are not uncommon, for example, in boxers or car occupants who during a head-on collision strike their head against the windshield or the steering wheel. In order to formulate protective measures against such an injury --especially with respect to the construction of automobiles --one must have knowledge of the conditions under which the injuries in question can arise. It is therefore important to know, among other things, the mechanical properties of the bridging veins.In the present study the stress strain relationship at different strain rates was studied by causing the veins to tear after a unidirectional pull.
Background: Substance use disorders have repeatedly been found to lead to premature death, i.e. drug-related death by disease, fatal intoxications, or trauma (accidents, suicide, undetermined suicide, and homicide). The present study examined the relationship between multi-drug substance use and natural and unnatural death.
The purpose of this study was to investigate the prevalence of toxic agents in attempted and completed suicides. The purpose was also to explore the sources of the drugs taken by suicide attempters. Verbal information on drug intake was collected from 280 suicide attempters during 1987-1990 in the Lund-Orup catchment area. Information on the sources of the drugs was collected from 143 of these attempters. The study also includes toxicological screening from 73 fatal poisonings in southern Sweden during 1989. According to verbal information, the most common drugs used by suicide attempters were benzodiazepines (51%), analgesics (29%) and antidepressants (20%). In suicide attempters, diazepam and levomepromazine were reported more than expected from prescription data. Toxicological screenings of fatal poisonings showed that benzodiazepines were most common (55%), followed by analgesics (38%), mainly propoxyphene (29%) and antidepressants (30%), mainly amitriptyline (22%). Amitriptyline and diazepam were more commonly detected in completed suicides than expected from prescription data. The most common sources of drugs to attempted suicides were physicians, and especially psychiatrists. We therefore conclude that continuous information to physicians on drug overdose is important, and it is also important to introduce alternative strategies to prevent suicidal behaviour.
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