Interdisziplin?re Leitlinien zur Diagnostik und Therapie der extrazerebralen Amyloidosen

Ohne Zusammenfassung     

Short-term lack of cerebral perfusion with good outcome. Advantages of early intracranial pressure monitoring

A 21-year-old man was injured by a tailboard of a truck. He suffered a severe head injury with bilateral depressed skull fractures necessitating surgical decompression. On admission to the hospital the patient showed bending to pain stimuli (Glasgow Coma Score 5). Anisocoria was noticed from the beginning. Initial intracranial pressure (ICP), measured 3 hours after injury, was 30 mm Hg, and the cerebral perfusion pressure (CPP) was 70 mm Hg. During surgical elevation of the skull fracture on the right side an unexplainable rise of ICP to values of 100 mm Hg occurred, which corresponded to the mean arterial blood pressure (MAP). At the same time both pupils were dilated and fixed indicating a lack of cerebral perfusion. Due to immediate trephination of the opposite side, the ICP was lowered to values below 20 mm Hg, and sufficient cerebral perfusion (above 50 mm Hg) was regained. The patient showed a good recovery and was transferred to a rehabilitation center 5 weeks after injury.This case report emphasizes the importance of early and continuous intracranial pressure monitoring for adequate therapy in neurosurgical emergencies.     

Cooling improves the writing performance of patients with writer's cramp.

Cooling of hand and forearm muscles by immersion in 15 degrees C cold water for 5 minutes improved the writing performance of patients with writer's cramp. Since abnormal processing of muscle spindle afferent discharges contributes to the pathology of writer's cramp, this effect might result from a reduction in muscle spindle activity by lowering muscle temperature. Cooling is a simple, cheap, and safe procedure, providing temporary relief for patients with writer's cramp.     

Thermally crosslinked rigid-rod aramids, 2. Fiber spinning and fiber properties

Fibers of three rigid-rod aromatic copolymers, produced by polycondensation of 2,2,6,6-tetraoxo-1,3,5,7-tetrahydro-2,6-dithia-s-indacene-4,8-diamine (DSDA), p-phenylenediamine and terephthaloyl dichloride, were spun from nematic solutions and characterized by wideangle X-ray-diffraction (WAXD) measurements and mechanical tests. A post-spin heat treatment was employed to improve the low degrees of orientation and crystallinity exhibited generally by the untreated fibers. The dominating crystal structures of the copolymers are similar to “modification I” of the well known fibers from poly(p-phenyleneterephthalamide) (PPTA). Thermally induced crosslinking of the fibers in the solid state was performed simultaneously with post-spin treatment. The influence of the annealing conditions on the mechanical fiber properties and the molecular order in the fibers was also investigated. All mechanical parameters were time-dependent, probably due to the generation of stable radicals during heat treatment. The radicals may give rise to chain scission.     

The Frictional Behavior of Coated Guiding Archwires

Background: The vast range of orthodontic wires made of different alloys makes it increasingly difficult for orthodontists to judge them. Coated orthodontic wires form a group of innovative guiding archwires. Material and Methods: In the present in vitro study the frictional behavior of eight coated wires of different dimensions was investigated in archwire-guided canine retraction in the upper jaw. For this purpose five superelastic nickel titanium alloy wires (Titanol^/reg; Low Force River Finish Gold and Gold 2: Forestadent^®, Pforzheim Germany; Titanol^® Superelastic tooth Sentalloy Ionguard™: GAC, Central Islip, NY, USA; NITI Imagination™: GAC, Central Islip, NY, USA), two #-titanium wires (TMA^® Low Friction Ionguard: Ormco, Glendora, CA, USA; TMA^® Low Friction Ionguard Purple: Ormco, Glendora, CA, USA) and one steel wire (Stainless steel Imagination™: GAC, Central Islip, NY, USA) were selected. The coatings were made of Teflon^® or polyethylene, and by ion implantation. Three uncoated archwires (Rematitan^® Lite Dimple; Dentaurum, Pforzheim, German; Titanol^® Low Force River Finish: Forestadent^®, Pforzheim, Germany; BioForce Sentalloy™: GAC, Central Islip, NY, USA) were used for comparison purposes. The force losses due to friction were measured using the Orthodontic Measurement and Simulation System (OMSS). Results: The results indicated that all coatings can reduce frictional losses compared with an uncoated reference wire by the same manufacturer. Measured frictional losses ranged from 48.3-6.1% with the Teflon^® coatings reducing the frictional losses to less than 10% in some cases. Conclusion: An unequivocal correlation between the surface roughness and frictional forces of the wires could not be verified by scanning electron microscopy. Zusammenfassung Hintergrund: Die Vielzahl an orthodontischen Drähten aus diversen Legierungen macht es die Kieferorthopäden immer schwerer, sie zu beurteilen. Eine Gruppe von neu angebotenen Führungsbögen stellen die beschichteten orthodontischen Drähte dar. Material und Methode: In der vorliegenden In-vitro-Studie wurde das Reibungsverhalten von acht beschichteten Drähten unterschiedlicher Dimension bei den bogengeführten Eckzahnretraktion im Oberkiefer untersucht. Neben fünf Nickel-Titan-Drähten (Titanol^® Low Force River Finish Gold und Gold 2: Fa. Forestadent^®; Titanol^® Superelastic zahnfarben: Fa. Forestadent^®; BioForce Sentalloy Ionguard™: Fa. GAC; NiTi Imagination™: Fa. GAC) wurden zwei #-Titan- (TMA Low Friction Iongard: Fa. Ormco; TMA Low Friction Ionguard Purple: Fa. Ormco) und ein Stahldraht (Stainless Steel Imagination™: Fa. GAC) ausgewählt. Die Beschichtungen bestanden aus Teflon^®, Polyethylen oder Ionenimplantation. Als Referenz wurden drei unbeschichtete Drähte (Rematitan^® Lite Dimple: Fa. Dentaurum; Titanol^® Low Force River Finish: Fa. Forestadent^®; BioForce Sentalloy™: Fa. GAC) in die Untersuchung einbezogen. Die Reibungsverluste wurden mit dem Orthodontischen Mess- und Simulations-System (OMSS) bestimmt. Ergebnisse: Die Ergebnisse zeigten, dass alle Beschichtungen, verglichen mit einem unbeschichteten Referenzdraht desselben Herstellers, eine Reduktion der Reibungsverluste bewirken. Die gemessenen Reibungsverluste lagen zwischen 48,3% und 6,1%, wobei bei Teflon^®-Beschichtungen der Reibungsverlust zum Teil auf unter 10% sank. Schlussfolgerung: Ein eindeutiger Zusammenhang zwischen der Oberflächenrauheit und den Friktionswerten der Drähte konnte anhand von rasterelektronenmikroskopischen Aufnahmen nicht bestätigt werden.