Stoß- und schlagbelastung des menschlichen schienbeins im drehversuch

Zusammenfassung Die menschliche Tibia wurde bei mittlerer und schneller Drehgeschwindigkeit bis zum Bruch des Knochens belastet. Die Ergebnisse der Zehntel- und Hundertstelsekundenfraktur werden mit denen bei langsamer Drehung (Sekundenfraktur) verglichen.Beim Drehstoß ( = 236°/sec) steigen die Frakturdrehmomente durchschnittlich um 17%, beim Drehschlag ( = 597°/sec) um 25% gegenüber der langsamen Drehung ( = 6°/sec). Die Elastizitätsgrenze, die die Verletzungsgrenze der Tibia darstellt, zeigt jeweils einen noch etwas höheren Anstieg. Die menschliche Tibia ist also gegenüber Stößen und Schlägen weniger empfindlich als gegenüber langsamen Belastungen, bei Drehung noch mehr als bei Biegung. Der Durchmesser des Schienbeinkopfes korrelierte im Vergleich zu zahlreichen weiteren Parametern am besten mit den Bruchwerten. Energieaufnahme, Form, Lage und Länge der Fraktur änderten sich auch bei schneller Drehung nicht, der Frakturdrehwinkel nahm bei Schlagbeanspruchung leicht ab.Für die Verletzungsprophylaxe beim alpinen Skilauf sind bei kurzer Krafteinwirkung die Trägheitsmomente des gesamten Beines zu berücksichtigen und erhöhen die o. g. Werte der Verletzungsgrenze erheblich.Aus den Ergebnissen werden Folgerungen für den Schutz vor typischen Skiverletzungen durch die Skibindung abgeleitet und können dazu beitragen, die passive Sicherheit beim Skilauf weiter zu erhöhen.

---

Hit and blow endurance of the human tibia in torsion testing

Summary Whole human tibiae were fractured with rapid loading rates of tenths and hundreds of a second for torsional fracture. Results were compared with data of experiments in slow loading during seconds.Loading time of 100 msec ( = 236°/s) increased the mean maximum torque of 17%, loading time of 10–40 msec ( = 597°/s) showed increase of 25%. In dynamic twisting the applied torque at the elasticity threshold, which represents the injury threshold of the tibia, has relatively higher values than the data at failure. The best correlation to the maximum torque exists at the frontal diameter of the tibia head.In dynamic twisting energies, site, figuration and length of fracture did not differ from those in quasistatic twisting procedures. With loading time of hundreds of a second the angle of fracture diminished.To prevent injuries in alpine skiing it is important to consider inertial effects of the whole leg in dynamic twisting. These effects raise the values of injury threshold distinctly. Practical conclusions are drawn from the results to get better passive safety in alpine skiing by perfecting release bindings.

     

The central action of pizotifen

The central action of the potential antidepressant drug pizotifen (Sandomigran) was studied in mice, rats and rabbits. Pizotifen in doses up to 10 mg/kg i.p. was ineffective in classic tests for antidepressant activity. It neither antagonized the effects of reserpine in rats (hypothermia, ptosis) nor potentiated the effects of amphetamine (in mice and rats), nialamide or L-dopa (in mice) on locomotor activity. However, its antidepressant activity was found in the despair test in rats.On the other hand, pizotifen inhibited the head twitch reaction induced by L-5-hydroxytryptophan in mice (ED₅₀=0.009 mg/kg, i.p.) and by 5-methoxytryptamine (+tranylcypromine) in rats (ED₅₀=0.45 mg/kg, i.p.). It also antagonized tryptamine-induced clonic convulsions of fore-paws in rats (ED₅₀=0.35 mg/kg, i.p.), and in doses of 5–10 mg/kg s.c. inhibited hyperthermia produced by LSD in rabbits. Finally, pizotifen (0.1–0.3 mg/kg, i.v.) inhibited or abolished LSD- or quipazine-induced stimulation of the hind limb flexor reflex of spinal rats; the above effect was not due to noradrenolytic action of the drug. These results suggest that pizotifen strongly blocks the central postsynaptic serotonin receptors.     

Magnetic resonance imaging measurements of the response of murine and human tumors to the vascular-targeting agent ZD6126.

PURPOSE: ZD6126 is a novel vascular targeting agent currently undergoing clinical evaluation. It acts by destabilizing the microtubulin of fragile and proliferating neoendothelial cells in tumors. The drug leads to blood vessel congestion, the selective destruction of the vasculature, and extensive necrosis in experimental tumors. The aim of the study reported here was to assess the ability of dynamic contrast enhanced magnetic resonance imaging (MRI) to measure the antivascular effects of ZD6126 in tumors. EXPERIMENTAL DESIGN: The work was carried out in mice bearing C38 colon adenocarcinoma and in patients with advanced cancers. MRI was performed before and 6 h (human tumors) or 24 h (C38 tumors) after i.v. drug administration. Contrast agent (gadolinium diethylenetriaminepentaacetate) enhancement was characterized by the initial area under the gadolinium diethylenetriaminepentaacetate uptake versus time curve (IAUC). IAUC reflects blood flow, vascular permeability, and the fraction of interstitial space. RESULTS: The median IAUC was reduced in all C38 tumors after ZD6126 administration [by 6-48% at 50 mg/kg (n = 3)], 58-91% at 100 mg/kg (n = 4), and 11-93% at 200 mg/kg (n = 6). In contrast, the administration of vehicle only led to no consistent change in median IAUC (n = 4). The ZD6126-induced changes in median IAUC appeared to be dose dependent (P = 0.045). No ZD6126-induced changes were apparent in murine muscle. Similar effects were seen in preliminary data from human tumors (11 tumors studied, 9 patients). At doses of 80 mg/m(2) and higher, the median IAUC post-ZD6126 treatment was reduced in all of the tumors studied (8 tumors, 6 patients) to 36-72% from the baseline value. There was a significant trend of increasing reductions with increasing exposure (P < 0.01). No drug-induced changes in human muscle or spleen IAUC were apparent. The reproducibility of the median IAUC parameter was investigated in patients. In 19 human tumors (measured in 19 patients) inter- and intratumor coefficients of variation were 64 and 18%. CONCLUSIONS: The contrast enhanced-MRI measured median IAUC is a useful end point for quantifying ZD6126 antivascular effects in human tumors.     

Noninvasive Tracking of Patient's Head Movements During Computer-Assisted Intranasal Microscopic Surgery

A noninvasive system designed for patient tracking during image-guided intranasal sinus surgery is described. It is based on optical digitizing with a custom-made registration and reference system, locatable surgical instruments, and a self-localizing operating microscope. Experimental and clinical results reveal a high degree of accuracy for the system. A mean spatial error of 0.82 ± 0.31 mm was determined for repositioning of the reference system in a plastic model of the skull. For the positioning of the microscope, a mean error of 2.3 ± 0.83 mm was calculated. Measurements of repositioning accuracy in 24 patients who received surgery for various sinus diseases had a mean spatial error of 1.56 ± 0.76 mm. The 95% error interval for locating intranasal structures using the surgical instrument was 2.05 mm, and it was 4.92 mm using the microscope. These results suggest that the use of our noninvasive registration and reference system may be effective, accurate, and useful for noninvasive tracking of patient movements in computer-assisted intranasal surgery.     

Glomerulocystic disease with hepatoblastoma in a neonate: a case report

Glomerulocystic disease (GCD) is a very rare condition. Only two previous reports have linked this condition with hepatoblastoma. We report a neonate with US evidence of grossly enlarged echogenic kidneys and features typical of hepatic fibrosis, complicated by the presence of a hepatoblastoma. The report discusses the differential diagnosis and highlights GCD as one cause of large, bright kidneys on US. It also adds further evidence to the suggested association between GCD and hepatoblastoma. Received: 15 May 1997 Accepted: 24 February 1998     

Pelvis-shoulder dysplasia

Pelvis-shoulder dysplasia is a rare focal skeletal dysostosis. We present the long-term follow-up of a patient with this condition. This patient has severe pelvic dysplasia but no involvement of the scapulae or clavicles. Despite the severity of the pelvic dysplasia, this man is able to function well. This is the fifth case of pelvis-shoulder dysplasia reported, but the only one documenting follow-up into adulthood. Received: 16 July 1997 Accepted: 4 February 1998     

Amantadine influences cognitive processing in patients with multiple sclerosis

We investigated the effect of amantadine on cognitive processing in patients with multiple sclerosis (MS) and fatigue with objective electrophysiological measures. Behavioral methods (Reaction Time, RT) and two different Event Related Potential (ERP) components measuring i) stimulus selection (Selection Negativity, SN) and ii) response selection (Lateralized Readiness Potential, LRP) were employed. Twenty-four patients with clinical definite MS (10 relapsing remitting and 14 secondary progressive) and confirmed fatigue in the past three months (Fatigue Severity Scale (FSS) > 4) were included. Patients were randomized in a double-blind, placebo-controlled cross-over design. We found a difference between the two treatments for ERP measures to stimuli with relevant colour starting at about 200 ms. This negativity had a higher amplitude during amantadine treatment regardless of treatment order. The RT did not differ significantly between the treated and untreated groups. Additional analysis indicated that patients with a disease duration of less than 7 years had a significant test position (practice effect), but no treatment effect, while patients with a longer MS duration showed no practice effect, but rather an improved reaction speed and increased ERP amplitude effects when treated with amantadine. The present findings suggest that amantadine exerts beneficial effects on early cognitive processes in patients with MS, but appears to be limited to subjects with a longer duration of the disease.     

英国补充治疗的成本效果：系统性综述

补充治疗（包括针灸和草药——编者注）是否应该整合纳入英国国民医疗卫生服务体系（NHS），成本效益的数据资料成为争论的关键问题。但是，就我们所知，以前没有人对英国补充疗法的成本效益做过研究。