Postural stability in older adults with a distal radial fracture

BACKGROUND: The physical risk factors leading to distal radial fractures are poorly understood. The goal of this study was to compare postural stability between older adults with and without a prior distal radial fragility fracture. METHODS: This case-control evaluation was performed at a single tertiary institution. The fracture cohort comprised 23 patients treated for a low-energy distal radial fracture within 6 to 24 months prior to this study. Twenty-three age and sex-matched control participants, without a prior fragility fracture, were selected from an outpatient clinic population. All participants completed a balance assessment with a computerized balance platform device. Dynamic motion analysis (DMA) scores ranging from 0 to 1,440 points are produced, with lower scores indicating better postural stability. Participants also completed validated questionnaires for general health quality (EuroQol-5D-3L [EQ-5D-3L]) and physical activity (Physical Activity Scale for the Elderly [PASE]) and comprehensive health and demographic information including treatment for compromised balance or osteoporosis. Statistical analysis compared data between cases and controls using either the Student t test or the Mann-Whitney U test. RESULTS: There were no significant differences (p > 0.05) in age, sex, body mass index, physical activity score, or EQ-5D-3L general health visual analog scale score between participants with or without prior distal radial fracture. The fracture cohort demonstrated poorer balance, with higher DMA scores at 933 points compared with 790 points for the control cohort (p = 0.008). Nineteen patients (83%) in the fracture cohort reported having dual x-ray absorptiometry (DXA) scans within 5 years prior to this study, but only 2 patients (9%) had ever been referred for balance training with physical therapy. CONCLUSIONS: Older adults who sustain low-energy distal radial fractures demonstrate impaired postural stability compared with individuals of a similar age who have not sustained such fractures. Following a distal radial fracture, these patients may benefit from interventions to improve postural stability. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence

Functional Comparison of the Two Bacillus anthracis Glutamate Racemases▿

Glutamate racemase activity in Bacillus anthracis is of significant interest with respect to chemotherapeutic drug design, because l-glutamate stereoisomerization to d-glutamate is predicted to be closely associated with peptidoglycan and capsule biosynthesis, which are important for growth and virulence, respectively. In contrast to most bacteria, which harbor a single glutamate racemase gene, the genomic sequence of B. anthracis predicts two genes encoding glutamate racemases, racE1 and racE2. To evaluate whether racE1 and racE2 encode functional glutamate racemases, we cloned and expressed racE1 and racE2 in Escherichia coli. Size exclusion chromatography of the two purified recombinant proteins suggested differences in their quaternary structures, as RacE1 eluted primarily as a monomer, while RacE2 demonstrated characteristics of a higher-order species. Analysis of purified recombinant RacE1 and RacE2 revealed that the two proteins catalyze the reversible stereoisomerization of l-glutamate and d-glutamate with similar, but not identical, steady-state kinetic properties. Analysis of the pH dependence of l-glutamate stereoisomerization suggested that RacE1 and RacE2 both possess two titratable active site residues important for catalysis. Moreover, directed mutagenesis of predicted active site residues resulted in complete attenuation of the enzymatic activities of both RacE1 and RacE2. Homology modeling of RacE1 and RacE2 revealed potential differences within the active site pocket that might affect the design of inhibitory pharmacophores. These results suggest that racE1 and racE2 encode functional glutamate racemases with similar, but not identical, active site features

Predicting epiphyseal stability of slipped capital femoral epiphysis with preoperative CT imaging.

BackgroundWe analyzed preoperative CT scans of hips with slipped capital femoral epiphysis (SCFE) for characteristics that could be predictive of intraoperative epiphyseal stability and developed a set of imaging criteria for stable and unstable SCFE. We then compared this grading system with the Loder classification.MethodsWe reviewed preoperative CT imaging to develop a SCFE stability classification system. Three orthopaedic surgeons used the classification system to grade stability on a series of SCFE hips. Kappa was used to evaluate intra- and interobserver reliability among the observers. A series of SCFE hips treated with open procedures in which intraoperative stability was determined under direct visualization was evaluated. Intraoperative stability was compared with stability ratings as determined by the CT classification system and the Loder classification system.ResultsInterobserver reliability among our three observers was κ = 0.823 (95% confidence interval (CI) 0.414 to 1.0; p < 0.001). Intraobserver reliability was κ = 0.901 (95% CI 0.492 to 1.31; p < 0.001). In all, 27 hips were used in the comparison of intraoperative stability with the Loder and CT classification systems. CT-predicted stability exhibited 78% concordance with intraoperative stability. The sensitivity and specificity of CT-predicted stability was 75% and 82%, respectively, versus Loder sensitivity of 69% and specificity of 91%.ConclusionThe CT evaluation method provided is easy to use and can help to improve the accuracy in determining preoperative epiphyseal stability, which may lead to improved treatment outcomes for this population.Level of evidenceIII

Impaired Annulus Fibrosus Development and Vertebral Fusion Cause Severe Scoliosis in Mice with Deficiency of c-Jun NH2-Terminal Kinases 1 and 2

© 2019 American Society for Investigative Pathology Mitogen-activated protein kinases, including c-Jun NH2-terminal kinase (JNK), play an important role in the development and function of a large variety of tissues. The skeletal phenotype of JNK1 and JNK2 double-knockout (dKO) mice (JNK1 fl/fl Col2-Cre/JNK2 −/− ) and control genotypes were analyzed at different embryonic and postnatal stages. JNK1/2 dKO mice displayed a severe scoliotic phenotype beginning during development that was grossly apparent around weaning age. Alcian blue staining at embryonic day 17.5 showed abnormal fusion of the posterior spinal elements. In adult mice, fusion of vertebral bodies and of spinous and transverse processes was noted by micro–computed tomography, Alcian blue/Alizarin red staining, and histology. The long bones developed normally, and histologic sections of growth plate and articular cartilage revealed no significant abnormalities. Histologic sections of the vertebral column at embryonic days 15.5 and 17.5 revealed an abnormal organization of the annulus fibrosus in the dKOs, with chondrocyte-like cells and fusion of dorsal processes. Spinal sections in 10-week–old dKO mice showed replacement of intervertebral disk structures (annulus fibrosus and nucleus pulposus) by cartilage and bone tissues, with cells staining for markers of hypertrophic chondrocytes, including collagen X and runt-related transcription factor 2. These findings demonstrate a requirement for both JNK1 and JNK2 in the normal development of the axial skeleton. Loss of JNK signaling results in abnormal endochondral bone formation and subsequent severe scoliosis