Delayed onset of partial epilepsy of temporal lobe origin following acute clioquinol encephalopathy.

Twelve cases have been reported in the literature to have developed acute, largely reversible, global amnesic syndromes some hours after ingesting substantial doses of clioquinol. Two of these cases presented again after asymptomatic intervals of some 12 years. Both had recently developed typical clinical and electroencephalographic evidence of partial epilepsy originating in a temporal lobe. The similarity of clinical events in these two subjects, the absence of any other known cause for their epilepsy and the fact that, in mice, acute clioquinol overdosage causes hippocampal and amygdaloid injury, suggest that the drug was responsible for both the acute encephalopathy and the epilepsy of delayed onset.     

N-phosphorylated amino acids as potential cytostatics]

Phosphoramidic dichlorides 3 are synthesized by nucleophilic attack of methyl 2-(1-ethylenimino)-alkanoates 1 on POCl3 or by the reaction of amino acid methyl ester hydrochlorides 2 with POCl3. Subsequent treatment of 3 with ethylenimine affords the TEPA-analogs 4, and with 3-(1-ethylenimino)-1-propanol (6) the IFOSFAMID analogous 1,3,2-oxaza-phosphorines 5, the cytostatic activity of which was tested in the P388-leukemia of the CD2F1-mouse.     

Computed tomography of retroperitoneal duodenal rupture in blunt abdominal trauma.

Two cases of retroperitoneal duodenum rupture following an upper abdominal blunt trauma are reported. Computed tomography (CT) demonstrates at best extraintestinal fluid and air in the retroperitoneum, especially if acquisition in right lateral decubitus is possible. Drawbacks of the method are also reviewed.     

Effects of fenoldopam on systemic and splanchnic haemodynamics and oxygen delivery/consumption relationship during hyperdynamic ovine endotoxaemia

Objective: To evaluate the use of a selective dopamine-1 agonist (fenoldopam) to provide selective splanchnic vasodilatation during sustained hypotensive endotoxaemia in sheep. Design: Randomised, controlled, experimental study. Setting: Animal research laboratory. Subjects: 12 adult instrumented, midazolam-sedated sheep. Interventions: The animals were randomised to receive a 20-min continuous infusion of dopamine (10 μg · kg^{− 1}· min^{− 1}), fenoldopam (10 μg · kg⁻¹· min^{− 1}) and noradrenaline (1 μg · kg^{− 1}· min^{− 1}) under control conditions and 12 h after endotoxaemia was induced by a continuous infusion of Escherichia coli endotoxin producing a stable hyperdynamic state simulating human septic shock. This drug dosage was selected to produce a 25–30 % increase in cardiac output by all three drugs during control conditions. Measurements and results: Systemic and splanchnic haemodynamic data were continuously obtained and systemic and splanchnic oxygen delivery (DO₂) and consumption (VO₂) were calculated. Hyperdynamic hypotensive endotoxaemia did not modify the splanchnic and renal reduction in DO₂ and the vasoconstrictive reactivity to noradrenaline observed during control conditions. In contrast, endotoxaemia abolished the fenoldopam and dopamine-induced increase in splanchnic DO₂ (especially in the coeliac trunk) observed during control conditions. Conclusions: During sustained hyperdynamic endotoxaemia, the dopaminergic-induced selective increase in coeliac trunk blood flow is abolished, most probably because of an already maximally vasodilated splanchnic circulation which prevented dopamine or fenoldopam to vasodilate this area further. Contrary to common belief, selective dopamine-1 agonist administration under these conditions may therefore not be beneficial to the splanchnic organs, though it improves whole body DO₂ and VO₂. Received: 22 May 1997 Accepted: 13 January 1998     

Biomechanical evaluation of bone-cement augmented Proximal Femoral Nail Antirotation blades in a polyurethane foam model with low density

Background

Helically shaped cephalic implants have proven their benefit to provide an improved stabilization of unstable hip fractures. However, cut out ratios up to 3.6% still occur. This in vitro study evaluated the biomechanical performance of a novel cement augmentation technique of the Proximal Femoral Nail Antirotation in surrogate femora.

Methods

Four study groups were formed out of 24 polyurethane foam specimens with low density. Proximal Femoral Nail Antirotation blades were implanted, either non-augmented, or augmented using 3 ml of injectable Polymethylmethacrylate bone-cement. The influence of implant mal-positioning was investigated by placing the blade either centered in the femoral head or off-centric in an anteroposterior direction. All specimens underwent cyclic loading under physiological conditions. Starting at 1000 N, the load was monotonically increased by 0.1 N/cycle until construct failure. Movement of the head was identified by means of optical motion tracking. Non-parametric test statistics were carried out on the cycles to failure, to compare between study groups.

Findings

Compared to control samples; augmented samples showed a significantly increased number of cycles to failure (P = 0.012). In the groups with centric position of the Proximal Femoral Nail Antirotation blade, cement augmentation led to an increase in loading cycles of 225%. In the groups with off-centric positioning of the blade, this difference was even more accentuated (933%).

Interpretation

Cement augmentation of the Proximal Femoral Nail Antirotation blade with small amounts of bone-cement for treatment of osteoporotic hip fractures clearly enhances fixation stability and carries high potential for clinical application.     

„Cutting out“ bei pertrochantären Frakturen – ein Problem der Osteoporose?

BACKGROUND: Despite the use of intramedullary fixation devices for the stabilisation of intertrochanteric fractures, the rate of complications is still high. One of the main reasons for burdensome reinterventions in 9-15% of cases is the cutting out of the fixation device through both the spongious bone and the cortical bone at the apex of the femoral head. This phenomenon is strongly connected to the reduction of the fractures achieved, the technical performance of the operation with optimal implant positioning and the resistance of the trabecular bone in the femoral head against deformation by the fixation device. The latter is very low in cases of severe osteoporosis. To prevent the complication of cutting out, it seems sensible to find the limits of load-bearing capacity of individual osteoporosis-associated features (i.e. bone mineral density) at which special additional measures or other techniques for the treatment of these patients are desired. METHODS: In a first step a new biomechanical standard test for implants stabilizing unstable trochanteric fractures was developed, which would provide predictable results depending on bone mineral density. In a second step a cut-off limit was sought for the bone density in the proximal femur that would afford stable fixation as measured by QCT (quantitative computed tomography) and DEXA (dual-energy X-ray absorptiometry). RESULTS: The developed test is realistic; it can be used to study typical cutting out phenomena on cadaver femora. In an unstable fracture model (type A 2.3 of the AO classification), the implants DHS with TSP, PFN and TGN showed a stable long-term load-bearing capacity at a bone mineral density of >0.6 g/cm3. In 5 of 32 specimens a cutting out phenomenon could be demonstrated, in 4 cases if the bone mineral density of the proximal femur was below 0.6 g/cm3 as measured by DEXA, and in one case poor performance of the implant (short screw in the femoral head) was evident. CONCLUSIONS: In cases of bone density of >0.6 g/cm3 in the proximal femur (DEXA), the standard implants for the fixation of unstable trochanteric fractures could guarantee fixation without cutting out. The critical value of sufficient bone density in our few cases seems to be around 0.6 g/cm3 as measured by DEXA. Further investigation is needed to define the limits of bone mineral density for a successful osteosynthesis. An appropriate augmentation of the trabecular bone of the femoral head or a new design of the central loading device could increase the load-bearing capacity and thus help to reduce the cutting out phenomenon. Another alternative could be the primary implantation of an endoprosthesis in the treatment of these patients.     

Mechanical comparison in cadaver specimens of three different 90-degree double-plate osteosyntheses for simulated C2-type distal humerus fractures with varying bone densities

OBJECTIVES: To investigate the bone-implant-anchorage of 90-degree double-plate osteosynthesis in simulated complete intra-articular distal humerus fractures using conventional reconstruction plates (CRP), locking compression plates (LCP), and distal humerus plates (DHP), depending on the bone mineral density (BMD) of the cadaver specimens. METHODS: Groups (CRP, LCP, DHP, n=8; LCP, DHP, n=13) in distal humerus cadaver bones were created based on BMD. The fracture model was an unstable intraarticular distal humerus fracture with a transverse osteotomy gap representing metaphyseal comminution (AO type 13-C2.3). Flexion and extension stiffness as well as cycles until failure due to screw pullout under cyclic loading were evaluated. Estimates of BMD values, below which failure was likely to occur, were determined. RESULTS: Stiffness values were not significantly different between groups (extension: P=0.881, flexion: P=0.547). Under cyclic loading, consistent screw pullout failure occurred at BMD values below about 400 mg/cm for CRP and below about 300 mg/cm for LCP constructs. Comparing BMD-matched groups of 8 and 13 specimens respectively, the failure rate was significantly lower for the DHP (0/8) than for the CRP (5/8; P=0.026) and tended to be lower for the DHP (0/13) as compared to the LCP (4/13; P=0.096). CONCLUSION: Bone-implant anchorage was different between locking and nonlocking plate constructs and depended on BMD. While in good bone quality implant choice was not critical, both locking plates provided superior resistance against screw loosening as compared to the CRP at low BMD values (<420 mg/cm). Based on our laboratory results, we conclude that locking plates such as the LCP and DHP are constructs designed to keep anatomical reduction in the presence of comminution and poor bone quality in a low intra-articular fracture of the distal humerus.     

Treatment of distal humeral fractures using conventional implants. Biomechanical evaluation of a new implant configuration

Background  

In the face of costly fixation hardware with varying performance for treatment of distal humeral fractures, a novel technique (U-Frame) is proposed using conventional implants in a 180° plate arrangement. In this in-vitro study the biomechanical stability of this method was compared with the established technique which utilizes angular stable locking compression plates (LCP) in a 90° configuration.