Femoroacetabular Impingement Syndrome: Evaluating Postoperative Rehabilitation Progress and Return to Sport Readiness

Femoroacetabular impingement syndrome (FAIS) is a common cause of non-arthritic hip pain and reduced physical activity in active young adults. It is defined as a motion-related disorder of the hip with a triad of symptoms, clinical signs, and imaging findings that represents symptomatic premature contact between the proximal femur and the acetabulum. There are two anatomical morphologies that can cause FAIS, cam, and pincer, and is a challenging clinical pathology. Patients typically undergo hip arthroscopy to repair damage to the joint and recess the bone causing the impingement. These procedures can result in positive outcomes for the patient, like reduced pain and symptoms, but research continues to investigate the optimal methods of ensuring a patient can return to their desired level of function and sports performance after surgery. Postoperative return to sport guidelines and their efficacy are highly variable. Guidelines are typically broken down to four, five, or six phases of rehabilitation, but return to sport criteria are also variable and based on criteria for other lower extremity injuries. Developing safe, effective, and reproducible guidelines for patients with FAIS after surgery is difficult because they lack clinical data and optimal methods for evaluating a return to sport readiness lack consensus. Practicing physiotherapists and orthopaedic surgeons who work with patients with FAIS appear to rely heavily on their own level of professional experience when making a postoperative return to sport recommendations rather than an established protocol. Their methods and outcomes for evaluating a patient\u27s functional progress at postoperative follow-up periods and return to sport readiness are highly variable depending on a clinician’s type of practice. Hip arthroscopy is an effective procedure to reduce impingement and improve a patient’s quality of life. A safe, effective, and reproducible postoperative return to sport guideline has not been established. Future studies should assess the if recommended outcomes suitable to evaluate return to sport readiness and determine which prognosis risk factors can predict if a patient with FAIS can safely return to sport after surgery to ensure they can remain physically active throughout their life

Fluoxetine prevents development of an early stress-related molecular signature in the rat infralimbic medial prefrontal cortex : implications for depression?

Background: Psychological stress, particularly in chronic form, can lead to mood and cognitive dysfunction and is a major risk factor in the development of depressive states. How stress affects the brain to cause psychopathologies is incompletely understood. We sought to characterise potential depression related mechanisms by analysing gene expression and molecular pathways in the infralimbic medial prefrontal cortex (ILmPFC), following a repeated psychological stress paradigm. The ILmPFC is thought to be involved in the processing of emotionally contextual information and in orchestrating the related autonomic responses, and it is one of the brain regions implicated in both stress responses and depression. Results: Genome-wide microarray analysis of gene expression showed sub-chronic restraint stress resulted predominantly in a reduction in transcripts 24 hours after the last stress episode, with 239 genes significantly decreased, while just 24 genes had increased transcript abundance. Molecular pathway analysis using DAVID identified 8 pathways that were significantly enriched in the differentially expressed gene list, with genes belonging to the brain-derived neurotrophic factor – neurotrophin receptor tyrosine kinase 2 (BDNF-Ntrk2) pathway most enriched. Of the three intracellular signalling pathways that are downstream of Ntrk2, real-time quantitative PCR confirmed that only the PI3K-AKT-GSK3B and MAPK/ERK pathways were affected by sub-chronic stress, with the PLCγ pathway unaffected. Interestingly, chronic antidepressant treatment with the selective serotonin reuptake inhibitor, fluoxetine, prevented the stress-induced Ntrk2 and PI3K pathway changes, but it had no effect on the MAPK/ERK pathway. Conclusions: These findings indicate that abnormal BDNF-Ntrk2 signalling may manifest at a relatively early time point, and is consistent with a molecular signature of depression developing well before depression-like behaviours occur. Targeting this pathway prophylactically, particularly in depression-susceptible individuals, may be of therapeutic benefit

Impaired myocardial function does not explain reduced left ventricular filling and stroke volume at rest or during exercise at high altitude

Impaired myocardial systolic contraction and diastolic relaxation have been suggested as possible mechanisms contributing to the decreased stroke volume (SV) observed at high altitude (HA). To determine whether intrinsic myocardial performance is a limiting factor in the generation of SV at HA, we assessed left ventricular (LV) systolic and diastolic mechanics and volumes in 10 healthy participants (aged 32 ± 7; mean ± SD) at rest and during exercise at sea level (SL; 344 m) and after 10 days at 5,050 m. In contrast to SL, LV end-diastolic volume was ∼19% lower at rest (P = 0.004) and did not increase during exercise despite a greater untwisting velocity. Furthermore, resting SV was lower at HA (∼17%; 60 ± 10 vs. 70 ± 8 ml) despite higher LV twist (43%), apical rotation (115%), and circumferential strain (17%). With exercise at HA, the increase in SV was limited (12 vs. 22 ml at SL), and LV apical rotation failed to augment. For the first time, we have demonstrated that EDV does not increase upon exercise at high altitude despite enhanced in vivo diastolic relaxation. The increase in LV mechanics at rest may represent a mechanism by which SV is defended in the presence of a reduced EDV. However, likely because of the higher LV mechanics at rest, no further increase was observed up to 50% peak power. Consequently, although hypoxia does not suppress systolic function per se, the capacity to increase SV through greater deformation during submaximal exercise at HA is restricted. during initial exposure to hypobaric hypoxia at high altitude (HA), cardiac output for a given absolute workload is increased to compensate for a lower arterial oxygen content before returning to baseline levels with acclimatization (8). However, after 2-5 days of acclimatization, the required cardiac output is generated through a lower stroke volume (SV) and higher heart rate (38). The reduced SV is suggestive of either lower ventricular filling, potentially caused in part by an impaired myocardial relaxation, or impaired ejection secondary to systolic contractile dysfunction. There is, however, a paucity of data in humans supporting a direct effect of hypoxia on myocardial function at HA (25, 41). The suggestion that hypoxia may impair myocardial systolic function during exercise was proposed nearly 50 years ago (3) and has been revisited more recently (27–29). Negative inotropic effects of hypoxia (arterial oxygen tension of 44 mmHg) have been shown in intact animal models (39) and isolated myocardial fibers under severe hypoxia (1% O2) (33). Exercise training under hypobaric hypoxia is also associated with altered mechanical properties at a cellular level in rodents (9), although chronic hypoxia alone did not decrease myofilament sensitivity to calcium. However, in contrast to animal studies, data in humans indicate that systolic function is maintained or enhanced at HA. For example, Suarez et al. (37) reported the maintenance of systolic function after gradual decompression to a barometric pressure of 282 mmHg, a finding that was subsequently confirmed by numerous investigations during acute and prolonged hypoxic exposure (6, 10, 12, 23, 31). However, of these studies, only Suarez et al. (37) investigated systolic function during light exercise (60 W), where function appeared to be maintained. It is not known whether systolic function is maintained at higher exercise intensities. It has also been speculated that reduced oxygen availability may impair diastolic relaxation at HA (15, 18) and thus explain the decreased left ventricular (LV) end-diastolic volume (EDV) commonly observed (2, 6, 18). However, despite numerous studies reporting a decrease in plasma volume and altered transmitral filling patterns (2, 6, 20), myocardial relaxation was only previously investigated during hypoxia in dogs (15), and no data exist examining LV relaxation during exercise at high altitude. By using sensitive, noninvasive imaging techniques (two-dimensional speckle tracking), it is now possible to examine the LV deformation mechanics (strain, twist, and untwist velocity) that underpin LV systolic and diastolic function. LV strain and twist have been shown to be sensitive measures of global and regional myocardial function, and reveal subclinical dysfunction in patients where ejection fraction is unchanged (16, 22). In addition, diastolic LV untwist velocity correlates well with invasive measures of LV stiffness and provides a temporal link between relaxation and the development of intraventricular pressure gradients (30, 43). Therefore, examination of LV mechanics at HA may determine whether the decreased SV observed at HA is dependent on impaired myocardial relaxation and/or myocardial contractile dysfunction or confirm previous findings of preserved ventricular function during exercise (37). We therefore assessed systolic and diastolic ventricular mechanics during incremental exercise at sea level and HA to examine whether impaired myocardial relaxation or systolic dysfunction explains the previously reported reduction in SV at HA. We hypothesized that at HA, 1) ventricular filling would be lower at rest and during exercise and would be accompanied by a reduction in untwist velocity and 2) systolic mechanics would be impaired during exercise at HA

Proapoptotic BH3-only proteins trigger membrane integration of prosurvival Bcl-w and neutralize its activity

Prosurvival Bcl-2–like proteins, like Bcl-w, are thought to function on organelles such as the mitochondrion and to be targeted to them by their hydrophobic COOH-terminal domain. We unexpectedly found, however, that the membrane association of Bcl-w was enhanced during apoptosis. In healthy cells, Bcl-w was loosely attached to the mitochondrial membrane, but it was converted into an integral membrane protein by cytotoxic signals that induce binding of BH3-only proteins, such as Bim, or by the addition of BH3 peptides to lysates. As the structure of Bcl-w has revealed that its COOH-terminal domain occupies the hydrophobic groove where BH3 ligands bind, displacement of that domain by a BH3 ligand would displace the hydrophobic COOH-terminal residues, allowing their insertion into the membrane. To determine whether BH3 ligation is sufficient to induce the enhanced membrane affinity, or to render Bcl-w proapoptotic, we mimicked their complex by tethering the Bim BH3 domain to the NH2 terminus of Bcl-w. The chimera indeed bound avidly to membranes, in a fashion requiring the COOH-terminal domain, but neither promoted nor inhibited apoptosis. These results suggest that ligation of a proapoptotic BH3-only protein alters the conformation of Bcl-w, enhances membrane association, and neutralizes its survival function

The genome of ε15, a serotype-converting, Group E1 Salmonella enterica-specific bacteriophage

AbstractThe genome sequence of the Salmonella enterica serovar Anatum-specific, serotype-converting bacteriophage ε15 has been completed. The nonredundant genome contains 39,671 bp and 51 putative genes. It most closely resembles the genome of φV10, an Escherichia coli O157:H7-specific temperate phage, with which it shares 36 related genes. More distant relatives include the Burkholderia cepacia-specific phage, BcepC6B (8 similar genes), the Bordetella bronchiseptica-specific phage, BPP-1 (8 similar genes) and the Photobacterium profundum prophage, P Pφpr1 (6 similar genes).ε15 gene identifications based on homologies with known gene families include the terminase small and large subunits, integrase, endolysin, two holins, two DNA methylase enzymes (one adenine-specific and one cytosine-specific) and a RecT-like enzyme. Genes identified experimentally include those coding for the serotype conversion proteins, the tail fiber, the major capsid protein and the major repressor. ε15's attP site and the Salmonella attB site with which it interacts during lysogenization have also been determined

Signaling in Secret: Pay-for-Performance and the Incentive and Sorting Effects of Pay Secrecy

Key Findings: Pay secrecy adversely impacts individual task performance because it weakens the perception that an increase in performance will be accompanied by increase in pay; Pay secrecy is associated with a decrease in employee performance and retention in pay-for-performance systems, which measure performance using relative (i.e., peer-ranked) criteria rather than an absolute scale (see Figure 2 on page 5); High performing employees tend to be most sensitive to negative pay-for- performance perceptions; There are many signals embedded within HR policies and practices, which can influence employees’ perception of workplace uncertainty/inequity and impact their performance and turnover intentions; and When pay transparency is impractical, organizations may benefit from introducing partial pay openness to mitigate these effects on employee performance and retention

Work-Unit Absenteeism: Effects of Satisfaction, Commitment, Labor Market Conditions, and Time

Prior research is limited in explaining absenteeism at the unit level and over time. We developed and tested a model of unit-level absenteeism using five waves of data collected over six years from 115 work units in a large state agency. Unit-level job satisfaction, organizational commitment, and local unemployment were modeled as time-varying predictors of absenteeism. Shared satisfaction and commitment interacted in predicting absenteeism but were not related to the rate of change in absenteeism over time. Unit-level satisfaction and commitment were more strongly related to absenteeism when units were located in areas with plentiful job alternatives

The Ginninderra CH4 and CO2 release experiment: An evaluation of gas detection and quantification techniques

A methane (CH4) and carbon dioxide (CO2) release experiment was held from April to June 2015 at the Ginninderra Controlled Release Facility in Canberra, Australia. The experiment provided an opportunity to compare different emission quantification techniques against a simulated CH4 and CO2 point source release, where the actual release rates were unknown to the participants. Eight quantification techniques were assessed: three tracer ratio techniques (two mobile); backwards Lagrangian stochastic modelling; forwards Lagrangian stochastic modelling; Lagrangian stochastic (LS) footprint modelling; atmospheric tomography using point and using integrated line sensors. The majority of CH4 estimates were within 20% of the actual CH4 release rate (5.8 g/min), with the tracer ratio technique providing the closest estimate to both the CH4 and CO2 release rates (100 g/min). Once the release rate was known, the majority of revised estimates were within 10% of the actual release rate. The study illustrates the power of measuring the emission rate using multiple simultaneous methods and obtaining an ensemble median or mean. An ensemble approach to estimating the CH4 emission rate proved successful with the ensemble median estimate within 16% for the actual release rate for the blind release experiment and within 2% once the release rate was known. The release also provided an opportunity to assess the effectiveness of stationary and mobile ground and aerial CH4 detection technologies. Sensor detection limits and sampling rates were found to be significant limitations for CH4 and CO2 detection. A hyperspectral imager\u27s capacity to image the CH4 release from 100 m, and a Boreal CH4 laser sensor\u27s ability to track moving targets suggest the future possibility to map gas plumes using a single laser and mobile aerial reflector