[Nonsurgical and surgical management of osteoporotic vertebral body fractures : Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)]. / Nichtoperative und operative Behandlung der osteoporotischen Wirbelkörperfraktur : Empfehlungen der Sektion Wirbelsäule der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU).

STUDY DESIGN: Prospective clinical cohort study (data collection); expert opinion (recommendation development). OBJECTIVES: Treatment options for nonsurgical and surgical management of osteoporotic vertebral body fractures differ widely. Based on the current literature, the knowledge of the experts, and their classification for osteoporotic fractures (OF classification), the Spine Section of the German Society for Orthopaedics and Trauma has now introduced general treatment recommendations. METHODS: A total of 707 clinical cases from 16 hospitals were evaluated. An OF classification-based score was developed for guidance in the option of nonsurgical versus surgical management. For every classification type, differentiated treatment recommendations were deduced. Diagnostic prerequisites for reproducible treatment recommendations were defined: conventional X­rays with consecutive follow-up images (standing position whenever possible), magnetic resonance imaging, and computed tomography scans. OF classification allows for upgrading of fracture severity during the course of radiographic follow-up. The actual classification type is decisive for the score. RESULTS: A score of less than 6 points advocates nonsurgical management; in cases with more than 6 points, surgical management is recommended. The primary goal of treatment is fast and painless mobilization. Because of the expected comorbidities in this age group, minimally invasive procedures are preferred. As a general rule, stability is more important than motion preservation. It is mandatory to restore the physiological loading capacity of the spine. If the patient was in a compensated unbalanced state at the time of fracture, reconstruction of the individual prefracture sagittal profile is sufficient. The instrumentation technique has to account for compromised bone quality. We recommend the use of cement augmentation or high purchase screws. The particular situations of injuries with neurological impairment, the necessity to fuse, multiple level fractures, consecutive and adjacent fractures and fractures in ankylosing spondylitis are addressed separately. CONCLUSIONS: The therapeutic recommendations presented here provide a reliable and reproducible basis to decide for the treatment choices available. However, intermediate clinical situations with a score of 6 points remain, allowing for both nonsurgical and surgical options. As a result, individualized treatment decisions may still be necessary. In the subsequent step, the recommendations presented will be further evaluated in a multicentre controlled clinical trial.

[The complicated course of a femoral shaft fracture in childhood]. / Komplizierter Verlauf einer Femurschaftfraktur im Kindesalter.

We report a difficult healing process after a femoral shaft fracture in childhood. We present surgical correction options of femoral shortening due to pseudarthrosis after elastic stable intramedullary nailing. First, we tried to establish distraction using an external fixator, followed by plate osteosynthesis. After material failure of plate osteosynthesis, we treated the refracture with intramedullary nailing, after which bone healing occurred.

[Course of operative treatment of a sacral insufficiency fracture : Successful or serious treatment?] / Behandlungsverlauf der operativen Versorgung einer Sakruminsuffizienzfraktur : Erfolgreiches oder folgenreiches Handeln?

A monolateral sacrum fracture was primarily diagnosed with a CT and treated with PMMA augmented SI screw fixation. The following CT showed an unexpected contralateral fracture which led to the need for a lumbopelvic stabilization. In the course of 6 months, successively occurring adjacent fractures required recurrent vertebroplasty. Most of these fractures could only be diagnosed through MRI. It remains unclear, whether initially even the contralateral sacral ala was fractured.

[Thoracolumbar spinal fractures in the elderly : Classification and treatment]. / Thorakolumbale Wirbelsäulenfrakturen beim alten Menschen : Klassifikation und Therapie.

Thoracolumbar fractures in the elderly are frequently associated with osteoporosis. Osteoporosis can cause fractures or be a significant comorbidity in traumatic fractures. The OF classification is based on conventional X­ray, computed tomography (CT) scan and magnetic resonance imaging (MRI). It is easy to use and provides a clinically relevant classification of the fractures. Therapeutic decisions are made based on the clinical and radiological situation by using the OF score. The score takes the current clinical situation including patient-specific comorbidities into consideration. The treatment recommendations are based on an expert consensus opinion and include conservative and operative options. If surgery is indicated, vertebral body augmentation, percutaneous stabilization and even open surgery can be used.

Neuromuscular Responses to 14 Weeks of Traditional and Daily Undulating Resistance Training.

This study compared traditional (TP) and daily undulating (DUP) periodization on muscle strength, EMG-estimated neural drive and muscle architecture of the quadriceps femoris (QF). 10 non-athletic females (24.4±3.2 years) performed 14 weeks of isometric training for the QF exercising 1 leg using TP and the contralateral leg using DUP. Intensities varied from 60% to 80% of MVC and the intensity zones and training volume were equated for each leg. Knee extension MVC, maximal voluntary QF-EMG activity and vastus lateralis (VL) muscle architecture were measured in both legs before, after 6 weeks and after 14 weeks of training using dynamometry, surface EMG and ultrasonography. Isometric MVC and maximal QF-EMG remained unaltered after 6 weeks of training, but were significantly (P<0.05) enhanced after 14 weeks in both legs (MVC: TP 24%, DUP 23%; QF-EMG: TP 45%, DUP 46%). VL-architecture remained unchanged following 6 weeks of training, but VL-muscle thickness (TP 17%, DUP 16%) and fascicle length (TP 16%, DUP 17%) displayed significant (P<0.05) enlargements after 14 weeks in both legs. Importantly, these temporal neuromuscular alterations displayed no significant differences between the training legs. Therefore, periodization may not act as a key trigger for neuromuscular adaptations.

[Aggravated reduction of the posterior malleolar fracture due to incarceration of the flexor digitorum longus tendon]. / Repositionshindernis des hinteren Volkmann-Dreiecks durch Interposition der Sehne des M. flexor digitorum longus.

The indications for stabilization of the posterior malleolus (Volkmann triangle) while fixing ankle fractures are controversially discussed. Detailed descriptions of possible obstacles to reduction are scarce. The following case describes the difficulty of reduction of the posterior malleolus caused by interposition of the flexor digitorum longus tendon. The fracture line of the posterior malleolus passed in an atypical manner vertically to the posterior-medial tibial margin with direct contact to the anatomical pathway of the tendon. The impaction of the tendon was already present in the computed tomography (CT) scan taken preoperatively but the tendon hindering malleolar reduction was first realized during surgery after several unsuccessful attempts at repositioning.

[Elbow dislocation with ipsilateral proximal radial shaft fracture and radial head dislocation]. / Ellenbogenluxation mit ipsilateraler proximaler Radiusschaftfraktur und Radiusköpfchenluxation.

Elbow dislocation with ipsilateral proximal radial shaft fracture and dislocated radial head is a rarely described injury. In this article we present the case of a 23-year-old man with this injury. After the initial diagnostics, the radial shaft fracture was osteosynthetically fixed, whereby the anatomical positions of all parts of the elbow joint were correctly aligned and the medial collateral ligament was reconstructed. After 4.5 months the radial shaft fracture was healed with nearly complete functional recovery of the upper extremity. Thus, a good outcome can be expected when all aspects of bony and ligamentous injuries are accurately addressed.

Comment on 'Temperature dependent optical properties of PbS nanocrystals'.

We address erroneous statements made by Nordin et al (2012 Nanotechnology 23 275701) claiming the inadequacy of an expression we, Ullrich et al (2011 Appl. Phys. Lett. 99 081901), used to fit the temperature dependence of the photoluminescence and the absorption of PbS quantum dots. We further correct a quote by Nordin et al, who, when referring to our work, mistakenly claimed temperature invariance of the Stokes shift.

Impact of Anxiety During Hospitalization on the Clinical Outcome of Patients With Osteoporotic Thoracolumbar Vertebral Fracture.

STUDY DESIGN: Multicenter prospective cohort study. OBJECTIVES: Anxiety in combination with osteoporotic vertebral compression fractures (OVCFs) of the spine remains understudied. The purpose of this study was to analyze whether anxiety has an impact on the short-term functional outcome of patients with an OVCF. Furthermore, a direct impact of the fracture on the patient's anxiety during hospitalization should be recognized. METHODS: All inpatients with an OVCF of the thoracolumbar spine from 2017 to 2020 were included. Trauma mechanism, analgetic medication, anti-osteoporotic therapy, timed-up-and-go test (TuG), mobility, Barthel index, Oswestry-Disability Index (ODI) and EQ5D-5L were documented.For statistical analysis, the U test, chi-square independence test, Spearman correlation, General Linear Model for repeated measures, Bonferroni analysis and Wilcoxon test were used. The item anxiety/depression of the EQ5D-5L was analyzed to describe the patients' anxiousness. RESULTS: Data from 518 patients from 17 different hospitals were evaluated. Fracture severity showed a significant correlation (r = .087, P = .0496) with anxiety. During the hospital stay, pain medication (P < .001), anti-osteoporotic medication (P < .001), and initiation of surgical therapy (P < .001) were associated with less anxiety. The anxiety of a patient at discharge was negatively related to the functional outcomes at the individual follow-up: TuG (P < .001), Barthel index (P < .001), ODI (P < .001) and EQ5D-5L (P < .001). CONCLUSIONS: Higher anxiety is associated with lower functional outcome after OVCF. The item anxiety/depression of the EQ5D-5L provides an easily accessible, quick and simple tool that can be used to screen for poor outcomes and may also offer the opportunity for a specific anxiety intervention.

Open versus minimally invasive fixation of thoracic and lumbar spine fractures in patients with ankylosing spinal diseases.

PURPOSE: Posterior multilevel fixation of traumatic instability in ankylosing spinal disease (ASD) can be performed by open surgery (OS) or minimally invasive surgery (MIS). We investigated whether both methods differ based on the reduction results and perioperative parameters. METHODS: In this retrospective cohort study, OS and MIS groups were investigated. The bisegmental Cobb angles and dislocation angles were measured using pre- and postoperative CT images, and the initial malalignment and achieved reduction were calculated. Cut-seam time, calculated blood loss, transfusion number, fluoroscopy time, pedicle screw placement accuracy, duration of ICU stay, in-patient stay, and complications (bleeding, postoperative thrombosis and embolism, and postoperative mortality) were recorded. RESULTS: Seventy-five ASD patients with spine fractures (Ø 75 ± 11 years, male: 52, female: 23) (MIS: 48; OS: 27) were included in this study. The extent of reduction did not differ in the OS and MIS groups (p = 0.465; MIS:- 1 ± 3°, OS:-2 ± 6°). The residual postoperative malalignment angle was not significantly different (p = 0.283). Seventy-eight of the implanted screws (11%) showed malpositioning. No difference was found between OS and MIS (MIS, 37 [7%]; OS, 41 [16%]; p = 0.095). MIS was associated with less blood loss (OS: 1.28 ± 0.78 l, MIS: 0.71 ± 0.57 l, p = 0.001), cut-seam time (MIS: 98 ± 44 min, OS: 166 ± 69 min, p < 0.001), and hospital stay (MIS: Ø14 ± 16 d, OS: Ø38 ± 49 d, p = 0.02) than OS. CONCLUSION: OS and MIS show equally limited performance in terms of the fracture reduction achieved. The MIS technique was superior to OS based on the perioperative outcome. Therefore, MIS should be preferred over OS for unstable spinal injuries, excluding C-type fractures, in ASD patients without neurological impairment.

Altered squat jumping mechanics after specific exercise.

This study examined squat jumping (SJ) mechanics following length restricted strength training regimens of the knee extensors and flexors. SJ from a 110 degrees knee joint angle starting position and isometric moment-knee angle relations of knee extensors and flexors were analysed in 16 athletes before and directly after 8 weeks of strength training regimens that were restricted to knee joint angles corresponding to long muscle-tendon unit (MTU) length for the knee extensors and flexors. SJ mechanics were studied using a two-dimensional kinematic model with three rigid bodies (upper leg, lower leg, foot) in combination with force plates measurements of ground reaction force in the right and left lower extremity. Centre of mass jumping height significantly (p<0.05) increased post training, but this was not explained by enhanced absolute power generation in the knee joint. However, post training small but significant (p<0.05) shifts to smaller knee joint angles occurred in the normalized [% Max.] knee joint angle dependent power generation in the right and left knee joint during SJ. The isometric moment-knee angle relation of the knee extensors was also significantly (p<0.05) shifted to longer MTU lengths of knee extensors. Length restricted strength training may alter the mechanical situation during both isometric contractions and dynamic athletic movements.

Frequency-dependent deformation of liquid crystal droplets in an external electric field.

Nematic droplets suspended in the isotropic phase of the same substance were subjected to alternating electrical fields of varying frequency. To keep the system at a constant nematic/isotropic volume ratio with constant droplet size, we carefully kept the temperature in the isotropic/nematic coexistence region, which was broadened by adding small amounts of a non-mesogenic liquid. Whereas the nematic droplets remained spherical at low (in the order of 10 Hz) and high frequencies (in the order of 1 kHz), at intermediate frequencies we observed a marked flattening of the droplets in the plane perpendicular to the applied field. Droplet deformation occurred both in liquid crystals (LCs) with positive and negative dielectric anisotropy. The experimental data can be quantitatively modelled with a combination of the leaky dielectric model and screening of the applied electric field due to finite conductivity.

Moment-angle relations after specific exercise.

This study examined the amount and time-course of shifts in the moment-knee angle relation of the quadriceps (QF) and hamstring (HAM) muscles in response to different length-restricted strength training regimens. Thirty-two athletes were divided into three different training groups (G1-3): G1 performed isometric training at knee joint angles corresponding to long muscle-tendon unit (MTU) length for QF and HAM; G2 conducted concentric-eccentric contraction cycles that were restricted to a knee joint range of motion corresponding to predominantly long MTU length for QF and HAM; G3 combined the protocols of G1 and G2. Moment-knee angle and EMG-knee angle relations of QF and HAM were measured on five different occasions: two times before, after five and eight weeks of training and four weeks post training. Moments and EMG-data of each subject were normalized to the largest value produced at any knee joint position [% Max.]. Obtained by curve fitting, the optimal knee joint angle for QF moment production was significantly (P<0.05) shifted to longer MTU length in G1 and G3 after 5 weeks of training and in G2 after 8 weeks of training. Contrary, no significant shifts were detected for HAM. Our data suggest that the predominant MTU length during loading is a major trigger for human force-length adaptations.

Cartography of neurexins: more than 1000 isoforms generated by alternative splicing and expressed in distinct subsets of neurons.

Neurexins, a family of cell surface proteins specific to brain, are transcribed from two promoters in three genes, resulting in three alpha- and three beta-neurexins. In situ hybridization revealed differential but overlapping distributions of neurexin isoforms in different classes of neurons. PCRs demonstrated that alpha-neurexins are alternatively spliced at five canonical positions, and beta-neurexins at two. Characterization of many independent bovine neurexin I alpha cDNAs suggests that different splice sites are used independently. This creates the potential to express more than 1000 distinct neurexin proteins in brain. The splicing pattern is conserved in rat and cow. Thus, in addition to somatic gene rearrangement (immunoglobulins and T cell receptors) and large gene families (odorant receptors), alternative splicing potentially represents a third mechanism for creating a large number of cell surface receptors that are expressed by specific subsets of cells.

Functional properties of multiple synaptotagmins in brain.

At least four forms of synaptotagmin are expressed in neurons. Of these, synaptotagmin I has an essential function in mediating Ca(2+)-triggered neurotransmitter release at hippocampal synapses, but the functional implications of multiple synaptotagmins are unknown. Synaptotagmins I-III exhibit a strikingly differential distribution between synapses, with most neurons coexpressing either synaptotagmins I or II with III. Synaptotagmin IV is present uniformly throughout the brain at low levels. Synaptotagmins III and IV are both coexpressed with synaptotagmin I in hippocampal synapses, suggesting that these synaptotagmins are not functionally redundant. The first C2 domains of synaptotagmins I-III exhibit similar Ca2+ affinities in phospholipid-binding assays, whereas that of synaptotagmin IV is unable to bind Ca2+. All synaptotagmins tested bind the clathrin-adaptor protein AP-2 with high affinity. Our results suggest that different synaptotagmins serve distinct but overlapping functions in neuronal membrane traffic, with synaptotagmins I and II representing alternative Ca2+ sensors in exocytosis and all synaptotagmins functioning as AP-2 receptors in endocytosis.

Tryptophan phosphorescence signals characteristic changes in protein dynamics at physiological temperatures.

The Arrhenius plot of the de-excitation rate of tryptophan triplet state deviates from linearity in the physiological temperature range for several proteins with buried tryptophans, similarly to the behaviour of enzyme activity. A model is presented featuring two de-excitation pathways whose effectiveness is regulated by protein dynamics.

Trp42 rotamers report reduced flexibility when the inhibitor acetyl-pepstatin is bound to HIV-1 protease.

The Q7K/L331/L631 HIV-1 protease mutant was expressed in Escherichia coli and the effect of binding a substrate-analog inhibitor, acetyl-pepstatin, was investigated by fluorescence spectroscopy and molecular dynamics. The dimeric enzyme has four intrinsic tryptophans, located at positions 6 and 42 in each monomer. Fluorescence spectra and acrylamide quenching experiments show two differently accessible Trp populations in the apoenzyme with k(q1) = 6.85 x 10(9) M(-1) s(-1) and k(q2) = 1.88 x 10(9) M(-1) s(-1), that merge into one in the complex with k(q) = 1.78 x 10(9) M(-1) s(-1). 500 ps trajectory analysis of Trp X1/X2 rotameric interconversions suggest a model to account for the observed Trp fluorescence. In the simulations, Trp6/Trp6B rotameric interconversions do not occur on this timescale for both HIV forms. In the apoenzyme simulations, however, both Trp42s and Trp42Bs are flipping between X1/X2 states; in the complexed form, no such interconverions occur. A detailed investigation of the local Trp environments sampled during the molecular dynamics simulation suggests that one of the apoenzyme Trp42B rotameric interconversions would allow indole-quencher contact, such as with nearby Tyr59. This could account for the short lifetime component. The model thus interprets the experimental data on the basis of the conformational fluctuations of Trp42s alone. It suggests that the rotameric interconversions of these Trps, located relatively far from the active site and at the very start of the flap region, becomes restrained when the apoenzyme binds the inhibitor. The model is thus consistent with associating components of the fluorescence decay in HIV-1 protease to ground state conformational heterogeneity.

Ultrastructural localization of in vivo-bound complement in bullous pemphigoid.

Antihuman complement component C3 labeled with horseradish peroxidase was used to reveal the ultrastructural localization of complement in two cases of bullous pemphigoid. The complement deposits were shown to be exclusively located in the space between the plasma membrane of the basal cells and the basal lamina. This corresponds exactly to the ultrastructural localization of immunoglobulins in bullous pemphigoid.

Partial purification of pemphigus-related epidermal antigens.

Epidermal antigens partially purified by either isoelectric focusing (the pH 5.2 peak) or concanavalin A (Con A) affinity chromatography react with Con A in tube precipitation reactions. Bands of identity between crude skin antigens, the Con A affinity antigens eluted with alpha-methyl glucoside and the pH 5.2 peak are formed in Ouchterlony gel with rabbit antisera (Rab) to the pH 5.2 antigen. Absorption of Rab or pemphigus antibodies (Pab) with A+ erythrocytes does not affect complement fixation reactions of Rab with the skin antigen nor abolish the ability of Pab to interact with the intercellular cement. The pH 5.2 epidermal antigens react weakly with Pab in tube precipitation reactions and only weakly, if at all, to inhibit Pab reactions in the region of the intercellular cement. High concentrations of Con A inhibit the Pab, peroxidase-anti-IgG tissue reaction whereas the converse inhibition does not occur. Simultaneous use of both Pab and Con A-perodixase reactions at Con A concentrations which do not inhibit Pab, causes enhanced tissue peroxidase reactions in the region of the intercellular cement. These preliminary data indicate that the Pab and Con A-reacting sites are localized on different molecules or antigenic determinants in the intercellular cement. They exclude the possibility that A-blood substances are involved in either site.