The glenoid track concept is insufficient to predict Bankart failures: a computed tomography scan study.

Background: The glenoid track concept identifies patients with "off-track" (engaging) Hill-Sachs lesions (HSLs) as poor candidates for arthroscopic Bankart repair (ABR) due to the high risk of shoulder instability recurrence. Purpose: To retrospectively calculate the glenoid track index, using preoperative computed tomography (CT) scans, in a cohort of patients with failed ABR. We hypothesized that all patients with a failed ABR would have engaging ("off-track") HSLs on preoperative CT scan. Type of Study: CT scan study. Methods: Preoperative CT scan of 45 patients, seen in our facility for failed ABR, was used to retrospectively calculate the glenoid track index. The risk of recurrence was also calculated for each patient using Instability Severity Index Score (ISI-Score) and Glenoid Track Instability Management Score (GTIMS). There were 37 failed isolated ABRs and 8 associated HS remplissage. The mean t age at surgery was 24 years (range, 15-52) and instability recurred at a mean of 29 months postoperative (range, 3-167). Results: Preoperative CT scan imaging identified "off-track" bony lesions in 85% of patients (38/45) and "on-track" lesions in 15% (7/45). No significant differences were noted between the 2 groups (off-track vs. on-track) regarding patient age, hyperlaxity, sports participation, size of HS lesion, or ISI-Score. The mean glenoid bone loss was 15.7% (range, 4-36%) with mean HS width was greater than 20 mm in 66% of CT scans. The preoperative ISI-Score was predictive of failures (>3 points in all patients) with no difference between on-track and off-track patients (6.3 ± 1.7 vs. 6.6 ± 1.7, P = .453). By contrast, the GTIMS did not predict failures as there was a significant difference between GTIMS for on-track and off-track patients (2.1 ± 1.3 vs. 6.6 ± 1.7). Conclusions: The glenoid track concept alone is insufficient to predict Bankart failures: in the present series of failed ABR, 15% of shoulders had "on-track" (non-engaging) lesions on preoperative CT scan. In patients, with "on-track" bony lesions, the ISI-Score is a useful predictive tool to detect patients at risk of failure, while the GTIMS is not.

Isokinetic and functional shoulder outcomes after arthroscopic capsulolabral stabilization.

INTRODUCTION: Shoulder stability is secured by dynamic and static stabilizers. Rotator cuff is responsible for dynamic stabilization. In cases of shoulder instability their activity is disturbed. Capsulolabral repair restores mainly static stabilization. This surgery treatment technique of shoulder instability was first described by Bankart in 1923. His idea, with further modifications, is commonly used up to this day. Evaluation of muscle shoulder recovery after stabilization should be one of the important criteria to allow patient to return to sport and work. However, not much isokinetic assessment after capsulolabral repair was described. The aim of this study were the following: the comparative assessment of the shoulder rotatory strength in patients following arthroscopic capsulolabral repair of unilateral anterior traumatic instability and clinical assessment with comparison of pre and post-operative results. MATERIAL AND METHODS: Forty-five patients, 14 women and 31 men, with an average follow-up of 4.4 years were tested bilaterally for internal and external rotation strength at four angular velocities. ASES and UCLA tests were collected before and after surgery. RESULTS: The values of peak moment and muscle power parameters were slightly lower for an operated shoulder in comparison to a healthy shoulder for the external rotation. Total work parameter in external rotation was significantly lower for the operated shoulder in comparison to the non-operated side. The internal/external muscle group balance was lower for the operated shoulder in comparison to reference values in the women group. Furthermore, both ASES and UCLA scores were significantly higher after operation. CONCLUSIONS: After arthroscopic capsulolabral shoulder stabilization, slight differences in isokinetic evaluation, especially in external shoulder rotation, occur. It affects rotators muscle balance. In functional evaluation significant improvement in shoulder function occurs.

Adenosine integrates light and sleep signalling for the regulation of circadian timing in mice.

The accumulation of adenosine is strongly correlated with the need for sleep and the detection of sleep pressure is antagonised by caffeine. Caffeine also affects the circadian timing system directly and independently of sleep physiology, but how caffeine mediates these effects upon the circadian clock is unclear. Here we identify an adenosine-based regulatory mechanism that allows sleep and circadian processes to interact for the optimisation of sleep/wake timing in mice. Adenosine encodes sleep history and this signal modulates circadian entrainment by light. Pharmacological and genetic approaches demonstrate that adenosine acts upon the circadian clockwork via adenosine A1/A2A receptor signalling through the activation of the Ca2+ -ERK-AP-1 and CREB/CRTC1-CRE pathways to regulate the clock genes Per1 and Per2. We show that these signalling pathways converge upon and inhibit the same pathways activated by light. Thus, circadian entrainment by light is systematically modulated on a daily basis by sleep history. These findings contribute to our understanding of how adenosine integrates signalling from both light and sleep to regulate circadian timing in mice.

Chemical Instability and Promiscuity of Arylmethylidenepyrazolinone-Based MDMX Inhibitors.

Targeting the protein-protein interaction between p53 and MDM2/MDMX (MDM4) represents an attractive anticancer strategy for the treatment of p53-competent tumors. Several selective and potent MDM2 inhibitors have been developed and entered the clinic; however, the repertoire of MDMX antagonists is still limited. The arylmethylidenepyrazolinone SJ-172550 has been reported as a selective MDMX antagonist; yet, uncertainties about its mechanism of action have raised doubts about its use as a chemical probe. Here, we show that, in addition to its unclear mode of action, SJ-172550 is unstable in aqueous buffers, giving rise to side products of unknown biological activity. Using an SJ-172550-derived affinity probe, we observed promiscuous binding to cellular proteins whereas cellular thermal shift assays did not reveal a stabilizing effect on MDMX. Overall, our results raise further questions about the interpretation of data using SJ-172550 and related compounds to investigate cellular phenotypes.

Vive la radiorésistance!: converging research in radiobiology and biogerontology to enhance human radioresistance for deep space exploration and colonization.

While many efforts have been made to pave the way toward human space colonization, little consideration has been given to the methods of protecting spacefarers against harsh cosmic and local radioactive environments and the high costs associated with protection from the deleterious physiological effects of exposure to high-Linear energy transfer (high-LET) radiation. Herein, we lay the foundations of a roadmap toward enhancing human radioresistance for the purposes of deep space colonization and exploration. We outline future research directions toward the goal of enhancing human radioresistance, including upregulation of endogenous repair and radioprotective mechanisms, possible leeways into gene therapy in order to enhance radioresistance via the translation of exogenous and engineered DNA repair and radioprotective mechanisms, the substitution of organic molecules with fortified isoforms, and methods of slowing metabolic activity while preserving cognitive function. We conclude by presenting the known associations between radioresistance and longevity, and articulating the position that enhancing human radioresistance is likely to extend the healthspan of human spacefarers as well.

Effect of arthroscopic techniques on joint volume in shoulder instability: Bankart repair versus capsular shift.

PURPOSE: The evaluation of glenohumeral joint volume in both unstable (with/without laxity) and stable shoulders (subacromial impingement) and volume reduction potential of arthroscopic techniques: (labral anchor repair vs. capsular shift). METHODS: Material was based on 133 patients: anterior shoulder instability without laxity (group I, n = 49), with laxity (group II, n = 22) and subacromial impingement (control group, n = 62) operated in 2010-2011. Group I received arthroscopic Bankart repair, group; II - arthroscopic anterior capsular plication, control group - subacromial decompression. Joint volume was measured by fluid aspiration into the syringe via arthroscope, before and after procedure. Then volume reduction potential was calculated. RESULTS: The following average values of initial joint volume were recorded: group I - 26.8 ml group II - 43.7 ml and the control group - 25.6 ml with significant differences: impingement vs. instability + laxity (p < 0.00001), impingement vs. instability without laxity (p = 0.0001). There was no significant difference between groups I and II. Joint volume was significantly reduced after labral repair (by average of 37 %, 13.8 ml, p < 0.0001). Capsular shift led to an even greater and more significant volume decrease (61 %, 26.7 ml, p < 0.001). Joint volume in the control group was reduced only by 11 %, 3.8 ml (p = 0.046). CONCLUSIONS: Patients with unstable shoulders have enlarged joint volume as compared to patients with subacromial impingement. Arthroscopic techniques lead to a significant joint volume reduction, with the most powerful effect for capsular shift. Level of Evidence - Level 2.

Measurement of active shoulder proprioception: dedicated system and device.

Proprioception is an essential part of shoulder stability and neuromuscular control. The purpose of the study was the development of a precise system of shoulder proprioception assessment in the active mode (Propriometr). For that purpose, devices such as the electronic goniometer and computer software had been designed. A pilot study was carried out on a control group of 27 healthy subjects, the average age being 23.8 (22-29) in order to test the system. The result of the assessment was the finding of the error of active reproduction of the joint position (EARJP). EARJP was assessed for flexion, abduction, external and internal rotation. For every motion, reference positions were used at three different angles. The results showed EARJP to range in 3-6.1°. The proprioception evaluation system (propriometr) allows a precise measurement of active joint position sense. The designed system can be used to assess proprioception in both shoulder injuries and treatment. In addition, all achieved results of normal shoulders may serve as reference to be compared with the results of forthcoming studies.