Enhancing mitochondrial proteostasis reduces amyloid-ß proteotoxicity.

Alzheimer's disease is a common and devastating disease characterized by aggregation of the amyloid-ß peptide. However, we know relatively little about the underlying molecular mechanisms or how to treat patients with Alzheimer's disease. Here we provide bioinformatic and experimental evidence of a conserved mitochondrial stress response signature present in diseases involving amyloid-ß proteotoxicity in human, mouse and Caenorhabditis elegans that involves the mitochondrial unfolded protein response and mitophagy pathways. Using a worm model of amyloid-ß proteotoxicity, GMC101, we recapitulated mitochondrial features and confirmed that the induction of this mitochondrial stress response was essential for the maintenance of mitochondrial proteostasis and health. Notably, increasing mitochondrial proteostasis by pharmacologically and genetically targeting mitochondrial translation and mitophagy increases the fitness and lifespan of GMC101 worms and reduces amyloid aggregation in cells, worms and in transgenic mouse models of Alzheimer's disease. Our data support the relevance of enhancing mitochondrial proteostasis to delay amyloid-ß proteotoxic diseases, such as Alzheimer's disease.

Co-expression network analysis of frontal cortex during the progression of Alzheimer's disease.

Mechanisms of Alzheimer's disease (AD) and its putative prodromal stage, amnestic mild cognitive impairment (aMCI), involve the dysregulation of multiple candidate molecular pathways that drive selective cellular vulnerability in cognitive brain regions. However, the spatiotemporal overlap of markers for pathway dysregulation in different brain regions and cell types presents a challenge for pinpointing causal versus epiphenomenal changes characterizing disease progression. To approach this problem, we performed Weighted Gene Co-expression Network Analysis and STRING interactome analysis of gene expression patterns quantified in frontal cortex samples (Brodmann area 10) from subjects who died with a clinical diagnosis of no cognitive impairment, aMCI, or mild/moderate AD. Frontal cortex was chosen due to the relatively protracted involvement of this region in AD, which might reveal pathways associated with disease onset. A co-expressed network correlating with clinical diagnosis was functionally associated with insulin signaling, with insulin (INS) being the most highly connected gene within the network. Co-expressed networks correlating with neuropathological diagnostic criteria (e.g., NIA-Reagan Likelihood of AD) were associated with platelet-endothelium-leucocyte cell adhesion pathways and hypoxia-oxidative stress. Dysregulation of these functional pathways may represent incipient alterations impacting disease progression and the clinical presentation of aMCI and AD.

MicroRNA-298 reduces levels of human amyloid-ß precursor protein (APP), ß-site APP-converting enzyme 1 (BACE1) and specific tau protein moieties.

Alzheimer's disease (AD) is the most common age-related form of dementia, associated with deposition of intracellular neuronal tangles consisting primarily of hyperphosphorylated microtubule-associated protein tau (p-tau) and extracellular plaques primarily comprising amyloid- ß (Aß) peptide. The p-tau tangle unit is a posttranslational modification of normal tau protein. Aß is a neurotoxic peptide excised from the amyloid-ß precursor protein (APP) by ß-site APP-cleaving enzyme 1 (BACE1) and the γ-secretase complex. MicroRNAs (miRNAs) are short, single-stranded RNAs that modulate protein expression as part of the RNA-induced silencing complex (RISC). We identified miR-298 as a repressor of APP, BACE1, and the two primary forms of Aß (Aß40 and Aß42) in a primary human cell culture model. Further, we discovered a novel effect of miR-298 on posttranslational levels of two specific tau moieties. Notably, miR-298 significantly reduced levels of ~55 and 50 kDa forms of the tau protein without significant alterations of total tau or other forms. In vivo overexpression of human miR-298 resulted in nonsignificant reduction of APP, BACE1, and tau in mice. Moreover, we identified two miR-298 SNPs associated with higher cerebrospinal fluid (CSF) p-tau and lower CSF Aß42 levels in a cohort of human AD patients. Finally, levels of miR-298 varied in postmortem human temporal lobe between AD patients and age-matched non-AD controls. Our results suggest that miR-298 may be a suitable target for AD therapy.

Pollen and yeast change nectar aroma and nutritional content alone and together, but honey bee foraging reflects only the avoidance of yeast.

Floral nectar often contains pollen and microorganisms, which may change nectar's chemical composition, and in turn impact pollinator affinity. However, their individual and combined effects remain understudied. Here, we examined the impacts of the nectar specialist yeast, Metschnikowia reukaufii, and the addition of sunflower (Hellianthus annus) pollen. Pollen grains remained intact, yet still increased yeast growth and amino acid concentrations in nectar, whereas yeast depleted amino acids. Pollen, but not yeast, changed nectar sugar concentrations by converting sucrose to its monomers. Both pollen and yeast contributed emissions from nectar, though yeast volatiles were more abundant than pollen volatiles. Yeast volatile emission was positively correlated with pollen concentration and cell density, and yeast depleted a subset of pollen-derived volatiles. Honey bees avoided foraging on yeast-inoculated nectar and foraged equally among uninoculated nectars regardless of pollen content, underscoring the importance of microbial metabolites in mediating pollinator foraging.

EXP1 is required for organisation of EXP2 in the intraerythrocytic malaria parasite vacuole.

Intraerythrocytic malaria parasites reside within a parasitophorous vacuole membrane (PVM) that closely overlays the parasite plasma membrane. Although the PVM is the site of several transport activities essential to parasite survival, the basis for organisation of this membrane system is unknown. Here, we performed proximity labeling at the PVM with BioID2, which highlighted a group of single-pass integral membrane proteins that constitute a major component of the PVM proteome but whose function remains unclear. We investigated EXP1, the longest known member of this group, by adapting a CRISPR/Cpf1 genome editing system to install the TetR-DOZI-aptamers system for conditional translational control. Importantly, although EXP1 was required for intraerythrocytic development, a previously reported in vitro glutathione S-transferase activity could not account for this essential EXP1 function in vivo. EXP1 knockdown was accompanied by profound changes in vacuole ultrastructure, including apparent increased separation of the PVM from the parasite plasma membrane and formation of abnormal membrane structures. Furthermore, although activity of the Plasmodium translocon of exported proteins was not impacted by depletion of EXP1, the distribution of the translocon pore-forming protein EXP2 but not the HSP101 unfoldase was substantially altered. Collectively, our results reveal a novel PVM defect that indicates a critical role for EXP1 in maintaining proper organisation of EXP2 within the PVM.

Sampling of Volatiles in Closed Systems: A Controlled Comparison of Three Solventless Volatile Collection Methods.

Complex inter-organismal communication among plants, insects, and microbes in natural and agricultural ecological systems is typically governed by emitted and perceived semiochemicals. To understand and ultimately utilize the role of volatile semiochemicals in these interactions, headspace volatiles are routinely collected and analyzed. Numerous collection systems are available (e.g., static or dynamic; adsorption or absorption) where the choice of technique should be dependent upon the plant, insect, or microbial ecological system studied, the information sought, and the limitations of each method. Within these constraints, it remains necessary that each method detects and provides the accurate in situ, or in vitro, volatile profile of the studied system. Herein, we analyzed and compared the pros and cons of three solventless, thermal desorption systems (SPME, Tenax/cold trap, SPDE) using a synthetic standard blend of compounds mimicking a simple natural blend (benzaldehyde, b-caryophyllene, (Z)-3-hexenol, 6-methyl-5-hepten-2-one, and limonene). Direct splitless injection and Super Q collections of the standard blend were used as controls. The results indicated that related qualitative, as well as quantitative differences, could be correlated with adsorbent sampling capacity and structural bias. The results for Tenax/cold trap and SPDE also were affected by sampled headspace volumes. All solventless techniques exhibited high analytical reproducibility, with SPME and SPDE providing ease of use, low cost, and minimal instrument modifications. The more complex Tenax/cold trap technique provided higher collection efficiency. Using these results, we provide guidance for technique selection for chemical communication applications.

Zea mays Volatiles that Influence Oviposition and Feeding Behaviors of Spodoptera frugiperda.

Fall armyworm (Spodoptera frugiperda) is a major global pest of many crops, including maize (Zea mays). This insect is known to use host plant-derived volatile organic compounds to locate suitable hosts during both its adult and larval stages, yet the function of individual compounds remains mostly enigmatic. In this study, we use a combination of volatile profiling, electrophysiological assays, pair-wise choice behavioral assays, and chemical supplementation treatments to identify and assess specific compounds from maize that influence S. frugiperda host location. Our findings reveal that methyl salicylate and (E)-alpha-bergamotene are oviposition attractants for adult moths but do not impact larval behavior. While geranyl acetate can act as an oviposition attractant or repellent depending on the host volatile context and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) is an oviposition deterrent. These compounds can also be attractive to the larvae when applied to specific maize inbreds. These data show that S. frugiperda uses different plant volatile cues for host location in its adult and larval stage and that the background volatile context that specific volatiles are perceived in, alters their impact as behavioral cues.

Microbial Co-Occurrence in Floral Nectar Affects Metabolites and Attractiveness to a Generalist Pollinator.

Microbial metabolism can shape cues important for animal attraction in service-resource mutualisms. Resources are frequently colonized by microbial communities, but experimental assessment of animal-microbial interactions often focus on microbial monocultures. Such an approach likely fails to predict effects of microbial assemblages, as microbe-microbe interactions may affect in a non-additive manner microbial metabolism and resulting chemosensory cues. Here, we compared effects of microbial mono- and cocultures on growth of constituent microbes, volatile metabolite production, sugar catabolism, and effects on pollinator foraging across two nectar environments that differed in sugar concentration. Growth in co-culture decreased the abundance of the yeast Metschnikowia reukaufii, but not the bacterium Asaia astilbes. Volatile emissions differed significantly between microbial treatments and with nectar concentration, while sugar concentration was relatively similar among mono- and cocultures. Coculture volatile emission closely resembled an additive combination of monoculture volatiles. Despite differences in microbial growth and chemosensory cues, honey bee feeding did not differ between microbial monocultures and assemblages. Taken together, our results suggest that in some cases, chemical and ecological effects of microbial assemblages are largely predictable from those of component species, but caution that more work is necessary to predict under what circumstances non-additive effects are important.

Microbial metabolites elicit distinct olfactory and gustatory preferences in bumblebees.

Animals such as bumblebees use chemosensory cues to both locate and evaluate essential resources. Increasingly, it is recognized that microbes can alter the quality of foraged resources and produce metabolites that may act as foraging cues. The distinct nature of these chemosensory cues however and their use in animal foraging remain poorly understood. Here, we test the hypothesis that species of nectar-inhabiting microbes differentially influence pollinator attraction and feeding via microbial metabolites produced in nectar. We first examined the electrophysiological potential for bumblebee (Bombus impatiens) antennal olfactory neurons to respond to microbial volatile organic compounds (mVOCs), followed by an olfactory preference test. We also assessed gustatory preferences for microbial-altered nectar through both no-choice and choice feeding assays. Antennal olfactory neurons responded to some mVOCs, and bees preferred nectar solutions inoculated with the bacterium Asaia astilbes over the yeast Metschnikowia reukaufii based on volatiles alone. However, B. impatiens foragers consumed significantly more Metschnikowia-inoculated nectar, suggesting distinct roles for mVOCs and non-volatile metabolites in mediating both attraction and feeding decisions. Collectively, our results suggest that microbial metabolites have significant potential to shape interspecific, plant-pollinator signalling, with consequences for forager learning, economics and floral host reproduction.

Nectar-inhabiting microorganisms influence nectar volatile composition and attractiveness to a generalist pollinator.

The plant microbiome can influence plant phenotype in diverse ways, yet microbial contribution to plant volatile phenotype remains poorly understood. We examine the presence of fungi and bacteria in the nectar of a coflowering plant community, characterize the volatiles produced by common nectar microbes and examine their influence on pollinator preference. Nectar was sampled for the presence of nectar-inhabiting microbes. We characterized the headspace of four common fungi and bacteria in a nectar analog. We examined electrophysiological and behavioral responses of honey bees to microbial volatiles. Floral headspace samples collected in the field were surveyed for the presence of microbial volatiles. Microbes commonly inhabit floral nectar and the common species differ in volatile profiles. Honey bees detected most microbial volatiles tested and distinguished among solutions based on volatiles only. Floral headspace samples contained microbial-associated volatiles, with 2-ethyl-1-hexanol and 2-nonanone - both detected by bees - more often detected when fungi were abundant. Nectar-inhabiting microorganisms produce volatile compounds, which can differentially affect honey bee preference. The yeast Metschnikowia reukaufii produced distinctive compounds and was the most attractive of all microbes compared. The variable presence of microbes may provide volatile cues that influence plant-pollinator interactions.

Outcomes of Elbow Arthroscopic Osteocapsular Arthroplasty.

PURPOSE: To evaluate the results of elbow arthroscopic osteocapsular arthroplasty (AOA) and determine which factors influence the outcome in a large group of patients with primary osteoarthritis. METHODS: A consecutive series of 46 patients with elbow osteoarthritis underwent AOA by a single surgeon (N.G.H.) between December 2005 and January 2013. Thirty-one patients returned for a comprehensive physical examination an average of 3.4 years later. The outcomes measures included visual analog scale (VAS), Mayo Elbow Performance Scores (MEPS), Disabilities of the Arm, Shoulder, and Hand (DASH), and American Shoulder and Elbow Society (ASES) scores. Preoperative and postoperative continuous variables were compared and a multivariable regression analysis was performed. RESULTS: Thirty-one patients with a mean age of 48 years (range, 19-77 years) returned for final follow-up, including 27 men and 4 women. Statistically significant improvement was observed in extension deficit (24° before surgery to 12° after surgery), flexion (126° before surgery to 135° after surgery), visual analog scale (6.4 before surgery to 1.6 after surgery), and Mayo Elbow Performance Scores (57 [poor] before surgery to 88 [good] after surgery). Subjective scores included a mean postoperative Disabilities of the Arm, Shoulder, and Hand score of 13 and an American Shoulder and Elbow Society pain score of 40. No complications were noted at final follow-up. CONCLUSIONS: Elbow AOA is a safe, efficacious treatment for patients with mild to moderate osteoarthritis. Our retrospective review found significant improvement in elbow motion, pain and clinical outcomes.

Incidence and Risk Factors for Extensor Pollicis Longus Rupture in Elastic Stable Intramedullary Nailing of Pediatric Forearm Shaft Fractures.

BACKGROUND: Elastic stable intramedullary nailing (ESIN) is an effective means of fixation for unstable, pediatric forearm shaft fractures with the benefit of smaller incisions, less soft tissue manipulation, and ease of removal. This study was designed to evaluate the incidence of and risk factors for extensor pollicis longus (EPL) rupture after fixation of pediatric radial shaft fractures with ESIN. METHODS: A retrospective review of all patients younger than 19 years who had a repair of a forearm fracture with flexible intramedullary nailing between 2006 and 2011 was performed. Nineteen consecutive patients were identified from the electronic medical record. All patients were treated with a titanium elastic nailing system using a dorsal approach to the radius. The patients were followed postoperatively for at least 2 years, and all fractures healed. An extensive chart review assessing for persistent pain, EPL function, and risk factors for EPL rupture was performed. Implants were removed in all but 1 patient. RESULTS: Seventeen records were available for review. Fourteen (82%) were male, and the mean age at time of fracture was 10 years old (range, 5 to 14 y). Follow-up averaged 5.5 years (range, 2.9 to 7.8 y). The mean weight was 32.7 kg for males and 50.6 kg for females corresponding to the 61st and 60th percentile respectively of weight-for-age (range, 8th to 99.9th percentile). Hardware was removed in all but 1 case, and the median time from surgery to hardware removal was 21 weeks (range, 8 to 63). Three of the 17 patients (18%) experienced rupture of the EPL. Two were treated with additional surgery following hardware removal, and one was untreated due to patient preference. None of the 17 patients (including those with rupture) had independent risk factors for tendon rupture: inflammatory arthritis, diabetes, or prior steroid use. Time to removal, patient age, and percentile of weight-for-age did not correlate with EPL rupture. CONCLUSIONS: Although ESIN of pediatric forearm shaft fractures has gained acceptance as a treatment option, our series of 17 patients revealed an 18% rate of EPL rupture. With this small patient cohort, no patient characteristics proved to be significant risk factors for predicting tendon rupture. However, awareness should be raised for an increased risk of EPL rupture with this fixation method. LEVEL OF EVIDENCE: Level IV-Therapeutic.

Effect of health risk assessment and counselling on health behaviour and survival in older people: a pragmatic randomised trial.

BACKGROUND: Potentially avoidable risk factors continue to cause unnecessary disability and premature death in older people. Health risk assessment (HRA), a method successfully used in working-age populations, is a promising method for cost-effective health promotion and preventive care in older individuals, but the long-term effects of this approach are unknown. The objective of this study was to evaluate the effects of an innovative approach to HRA and counselling in older individuals for health behaviours, preventive care, and long-term survival. METHODS AND FINDINGS: This study was a pragmatic, single-centre randomised controlled clinical trial in community-dwelling individuals aged 65 y or older registered with one of 19 primary care physician (PCP) practices in a mixed rural and urban area in Switzerland. From November 2000 to January 2002, 874 participants were randomly allocated to the intervention and 1,410 to usual care. The intervention consisted of HRA based on self-administered questionnaires and individualised computer-generated feedback reports, combined with nurse and PCP counselling over a 2-y period. Primary outcomes were health behaviours and preventive care use at 2 y and all-cause mortality at 8 y. At baseline, participants in the intervention group had a mean ± standard deviation of 6.9 ± 3.7 risk factors (including unfavourable health behaviours, health and functional impairments, and social risk factors) and 4.3 ± 1.8 deficits in recommended preventive care. At 2 y, favourable health behaviours and use of preventive care were more frequent in the intervention than in the control group (based on z-statistics from generalised estimating equation models). For example, 70% compared to 62% were physically active (odds ratio 1.43, 95% CI 1.16-1.77, p = 0.001), and 66% compared to 59% had influenza vaccinations in the past year (odds ratio 1.35, 95% CI 1.09-1.66, p = 0.005). At 8 y, based on an intention-to-treat analysis, the estimated proportion alive was 77.9% in the intervention and 72.8% in the control group, for an absolute mortality difference of 4.9% (95% CI 1.3%-8.5%, p = 0.009; based on z-test for risk difference). The hazard ratio of death comparing intervention with control was 0.79 (95% CI 0.66-0.94, p = 0.009; based on Wald test from Cox regression model), and the number needed to receive the intervention to prevent one death was 21 (95% CI 12-79). The main limitations of the study include the single-site study design, the use of a brief self-administered questionnaire for 2-y outcome data collection, the unavailability of other long-term outcome data (e.g., functional status, nursing home admissions), and the availability of long-term follow-up data on mortality for analysis only in 2014. CONCLUSIONS: This is the first trial to our knowledge demonstrating that a collaborative care model of HRA in community-dwelling older people not only results in better health behaviours and increased use of recommended preventive care interventions, but also improves survival. The intervention tested in our study may serve as a model of how to implement a relatively low-cost but effective programme of disease prevention and health promotion in older individuals. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number: ISRCTN 28458424.

In-field Volatile Analysis Employing a Hand-held Portable GC-MS: Emission Profiles Differentiate Damaged and Undamaged Yellow Starthistle Flower Heads.

INTRODUCTION: Understanding the complex chemical signalling of plants and insects is an important component of chemical ecology. Accordingly, the collection and analysis of chemical cues from plants in their natural environment is integral to elucidation of plant-insect communications. Remote plant locations and the need for a large number of replicates make in situ headspace analyses a daunting logistical challenge. A hand-held, portable GC-MS system was used to discriminate between damaged and undamaged Centaurea solstitialis (yellow starthistle) flower heads in both a potted-plant and natural setting. OBJECTIVE: To determine if a portable GC-MS system was capable of distinguishing between undamaged and mechanically damaged plant treatments, and plant environments. METHODOLOGY: A portable GC-MS utilising needle trap adsorbent technology was used to collect and analyse in situ headspace volatiles of varying yellow starthistle treatments. Principal component analysis (PCA) was used to distinguish treatments and identify biomarker volatiles. Analysis of variance (ANOVA) was used to determine differences between treatment volatile amounts. RESULTS: The portable GC-MS system detected 31 volatiles from the four treatments. Each GC-MS run was completed in less than 3 min. PCA showed four distinct clusters representing the four treatments - damaged and undamaged potted plant, and damaged and undamaged natural plant. Damage-specific volatiles were identified. CONCLUSION: The portable GC-MS system distinguished the treatments based on their detected volatile profiles. Additional statistical analysis identified five possible biomarker volatiles for the treatments, among them cyclosativene and copaene, which indicated damaged flower heads.

Genome-wide association study in multiple human prion diseases suggests genetic risk factors additional to PRNP.

Prion diseases are fatal neurodegenerative diseases of humans and animals caused by the misfolding and aggregation of prion protein (PrP). Mammalian prion diseases are under strong genetic control but few risk factors are known aside from the PrP gene locus (PRNP). No genome-wide association study (GWAS) has been done aside from a small sample of variant Creutzfeldt-Jakob disease (CJD). We conducted GWAS of sporadic CJD (sCJD), variant CJD (vCJD), iatrogenic CJD, inherited prion disease, kuru and resistance to kuru despite attendance at mortuary feasts. After quality control, we analysed 2000 samples and 6015 control individuals (provided by the Wellcome Trust Case Control Consortium and KORA-gen) for 491032-511862 SNPs in the European study. Association studies were done in each geographical and aetiological group followed by several combined analyses. The PRNP locus was highly associated with risk in all geographical and aetiological groups. This association was driven by the known coding variation at rs1799990 (PRNP codon 129). No non-PRNP loci achieved genome-wide significance in the meta-analysis of all human prion disease. SNPs at the ZBTB38-RASA2 locus were associated with CJD in the UK (rs295301, P = 3.13 × 10(-8); OR, 0.70) but these SNPs showed no replication evidence of association in German sCJD or in Papua New Guinea-based tests. A SNP in the CHN2 gene was associated with vCJD [P = 1.5 × 10(-7); odds ratio (OR), 2.36], but not in UK sCJD (P = 0.049; OR, 1.24), in German sCJD or in PNG groups. In the overall meta-analysis of CJD, 14 SNPs were associated (P < 10(-5); two at PRNP, three at ZBTB38-RASA2, nine at nine other independent non-PRNP loci), more than would be expected by chance. None of the loci recently identified as genome-wide significant in studies of other neurodegenerative diseases showed any clear evidence of association in prion diseases. Concerning common genetic variation, it is likely that the PRNP locus contains the only strong risk factors that act universally across human prion diseases. Our data are most consistent with several other risk loci of modest overall effects which will require further genetic association studies to provide definitive evidence.

Risk factors for the development of heterotopic ossification after acetabular fracture fixation.

BACKGROUND: Heterotopic ossification (HO) is a common complication of the operative treatment of acetabular fractures. Although the surgical approach has been shown to correlate with the development of ectopic bone, specific risk factors have not been elucidated. QUESTIONS/PURPOSES: The purposes of this study were to determine specific risk factors associated with the development of severe HO and the frequency with which patients develop severe HO after acetabular fracture fixation through an isolated Kocher-Langenbeck approach. METHODS: Using an institutional orthopaedic trauma database at a regional Level I trauma center, patients undergoing open treatment of acetabular fractures during the study period (January 2000 to January 2010) were identified. A review of medical records and imaging studies was performed on 508 patients who were treated by the senior author (MR) through an isolated Kocher-Langenbeck approach. During the study period, the senior author used indomethacin for HO prophylaxis in patients who had ipsilateral femur fracture treated with antegrade reamed medullary nailing or severe local soft tissue injury; 49 (10%) of the patients he treated with the Kocher-Langenbeck approach received prophylaxis, and they were excluded from this study, leaving a total of 459 patients who met inclusion criteria. Of those, 147 (29%) were lost to followup or did not have radiographs both before and at a minimum of 6 weeks (median, 1 week; range, 0-3 weeks), leaving 312 (61% of the patients treated with the Kocher-Langenbeck approach during this time) available for this analysis. Demographic data as well as information related to cause of injury, associated periacetabular findings, other system injuries, and treatment were gathered. Final followup radiographs were assessed for the presence of ectopic bone by two of the authors (TJO, AS) using the modified Brooker classification. Logistic regression was performed to identify possible predictors of development of severe ectopic bone. RESULTS: The only predictor we identified for the development of severe HO was the need for prolonged mechanical ventilation (odds ratio, 7.1; 95% confidence interval, 2.9-17.3; p=0.001). Injury Severity Score, sex, presence of comminution, femoral head impaction, dislocation, degloving injury, debris in the joint, number of other fractures, and head and chest Abbreviated Injury Score>2 did not correlate with severe HO. Severe HO (Brooker Class III or IV) developed in 38 of 312 patients (12%). CONCLUSIONS: Patients with prolonged mechanical ventilation might benefit from HO prophylaxis given the increased risk of developing severe HO in this patient population. However, future prospective studies need to be performed to verify this finding given the fact that a considerable number of patients were prophylactically treated in this study. LEVEL OF EVIDENCE: Level IV, prognosticstudy. See Guidelines for Authors for a complete description of levels of evidence.

Primary cilia membrane assembly is initiated by Rab11 and transport protein particle II (TRAPPII) complex-dependent trafficking of Rabin8 to the centrosome.

Sensory and signaling pathways are exquisitely organized in primary cilia. Bardet-Biedl syndrome (BBS) patients have compromised cilia and signaling. BBS proteins form the BBSome, which binds Rabin8, a guanine nucleotide exchange factor (GEF) activating the Rab8 GTPase, required for ciliary assembly. We now describe serum-regulated upstream vesicular transport events leading to centrosomal Rab8 activation and ciliary membrane formation. Using live microscopy imaging, we show that upon serum withdrawal Rab8 is observed to assemble the ciliary membrane in ∼100 min. Rab8-dependent ciliary assembly is initiated by the relocalization of Rabin8 to Rab11-positive vesicles that are transported to the centrosome. After ciliogenesis, Rab8 ciliary transport is strongly reduced, and this reduction appears to be associated with decreased Rabin8 centrosomal accumulation. Rab11-GTP associates with the Rabin8 COOH-terminal region and is required for Rabin8 preciliary membrane trafficking to the centrosome and for ciliogenesis. Using zebrafish as a model organism, we show that Rabin8 and Rab11 are associated with the BBS pathway. Finally, using tandem affinity purification and mass spectrometry, we determined that the transport protein particle (TRAPP) II complex associates with the Rabin8 NH(2)-terminal domain and show that TRAPP II subunits colocalize with centrosomal Rabin8 and are required for Rabin8 preciliary targeting and ciliogenesis.

Volar plate fixation failure for volar shearing distal radius fractures with small lunate facet fragments.

PURPOSE: To determine the percentage of AO B3 distal radius fractures that lose reduction after operative fixation and to see whether fracture morphology, patient factors, or fixation methods predict failure. We hypothesized that initial fracture displacement, amount of lunate facet available for fixation, plate position, and screw fixation would be significant risk factors for loss of reduction. METHODS: A prospective, observational review was conducted of 51 patients (52 fractures) with AO B3 (volar shearing) distal radius fractures treated operatively between January 2007 and June 2012. We reviewed a prospective distal radius registry to determine demographic data, medical comorbidities, and physical examination findings. Radiographs were evaluated for AO classification, loss of reduction, length of volar cortex available for fixation, and adequacy of stabilization of the lunate facet fragment with a volar plate. Preoperative data were compared between patients who maintained radiographic alignment and those with loss of reduction. A multivariate logistic regression analysis was completed to determine significant predictors of loss of reduction. RESULTS: Volar shearing fractures with separate scaphoid and lunate facet fragments (AO B3.3), preoperative lunate subsidence distance, and length of volar cortex available for fixation were significant predictors for loss of reduction; the latter was significant in multivariate analysis. Plate position and number of screws used to stabilize the lunate facet were not statistically different between groups. CONCLUSIONS: Patients with AO B3.3 fractures with less than 15 mm of lunate facet available for fixation, or greater than 5 mm of initial lunate subsidence, are at risk for failure even if a volar plate is properly placed. In these cases, we recommend additional fixation to maintain reduction of the small volar lunate facet fracture fragments in the form of plate extensions, pins, wires, suture, wire forms, or mini screws. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

The incidence of trigger digit after carpal tunnel release in diabetic and nondiabetic patients.

PURPOSE: To determine whether patients with diabetes mellitus (DM) are at greater risk for developing postoperative trigger digits (TD) after carpal tunnel release (CTR) compared with patients without diabetes. METHODS: A retrospective review of our electronic medical records identified all patients who had undergone CTR by a single hand fellowship-trained surgeon from September 2007 through May 2012. For patients with DM, additional information regarding method of disease control and hemoglobin A1c (HbA1c) level was recorded. We recorded HbA1c levels 3 months before and 3 months after CTR. The location and time to development of postoperative, new-onset TD were recorded for each case. Statistical testing included chi-square or Student t test and multivariate logistic regression analysis. RESULTS: Of the 1,217 CTRs, 214 had DM. Of the 1,003 CTRs in cases without DM, 3% developed TD within 6 months of CTR and 4% within 1 year of CTR, compared with 8% and 10%, respectively, for diabetic cases. A multivariate regression analysis revealed DM as a significant risk factor for developing TD after CTR at 6 and 12 months. We found no significant association between HbA1c level at the time of CTR and the likelihood of developing TD. CONCLUSIONS: The incidence of TD after CTR was higher in the diabetic population compared with a nondiabetic cohort. The presence of DM rather than its severity was the most important factor for developing TD. Preoperative counseling for patients with DM undergoing CTR may alert them to the possibility of developing TD. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

An overview of plant volatile metabolomics, sample treatment and reporting considerations with emphasis on mechanical damage and biological control of weeds.

INTRODUCTION: The technology for the collection and analysis of plant-emitted volatiles for understanding chemical cues of plant-plant, plant-insect or plant-microbe interactions has increased over the years. Consequently, the in situ collection, analysis and identification of volatiles are considered integral to elucidation of complex plant communications. Due to the complexity and range of emissions the conditions for consistent emission of volatiles are difficult to standardise. OBJECTIVE: To discuss: evaluation of emitted volatile metabolites as a means of screening potential target- and non-target weeds/plants for insect biological control agents; plant volatile metabolomics to analyse resultant data; importance of considering volatiles from damaged plants; and use of a database for reporting experimental conditions and results. METHOD: Recent literature relating to plant volatiles and plant volatile metabolomics are summarised to provide a basic understanding of how metabolomics can be applied to the study of plant volatiles. RESULTS: An overview of plant secondary metabolites, plant volatile metabolomics, analysis of plant volatile metabolomics data and the subsequent input into a database, the roles of plant volatiles, volatile emission as a function of treatment, and the application of plant volatile metabolomics to biological control of invasive weeds. CONCLUSION: It is recommended that in addition to a non-damaged treatment, plants be damaged prior to collecting volatiles to provide the greatest diversity of odours. For the model system provided, optimal volatile emission occurred when the leaf was punctured with a needle. Results stored in a database should include basic environmental conditions or treatments.