Common peroneal nerve palsy complicating knee dislocation and bicruciate ligaments tears

SummaryIntroductionThe occurrence rate of common peroneal nerve (CPN) palsy associated with knee dislocation or bicruciate ligament injury ranges from 10 to 40%. The present study sought first to describe the anatomic lesions encountered and their associated prognoses and second to recommend adequate treatment strategy based on a prospective multicenter observational series of knee ligament trauma cases.Material and methodsTwelve out of 67 knees treated for dislocation or bicruciate lesion presented associated CPN palsy: two females, 10 males; mean age, 32 years. Four sports injuries, three traffic accidents and five other etiologies led to seven complete dislocations and five bicruciate ruptures. Four cases involved associated popliteal artery laceration ischemia; one of the dislocations was open. Paralysis was total in eight cases and partial in four. There were two complete ruptures, three contusions with CPN in continuity stretch lesions and three macroscopically normal aspects.ResultsAt a minimum 1 year's follow-up, regardless of the initial surgical technique performed, recovery was complete in six cases, partial (in terms of motor function) in one and absent in five. Without specific CPN surgery, spontaneous recovery was partial in one case, complete in two and absent in none. Following simple emergency or secondary neurolysis, remission was total in four cases and absent in one. Three nerve grafts were all associated with non-recovery.DiscussionThe present results agree with literature findings. Palsy rates varied with trauma circumstances and departmental recruitment. Neurologic impairment was commensurate to ligamentary damages. The anatomic status of the CPN, subjected to violent traction by dislocation, was the most significant prognostic factor for neurologic recovery. In about 25% of dislocations, contusion-elongation over several centimeters was associated with as poor a prognosis as total rupture. CPN neurolysis is recommended when early clinical and EMG recovery fails to progress and/or in case of lateral ligamentary reconstruction. Possible peripheral nerve impairment needs to be included in the overall functional assessment of treatment for severe ligaments injuries and knee dislocation.Level of evidenceLevel IV, prospective study

A computed tomography based study on rotational alignment accuracy of the femoral component in total knee arthroplasty using computer-assisted orthopaedic surgery

Rotation of the femoral component in total knee arthroplasty (TKA) is of high importance in respect of the balancing of the knee and the patellofemoral joint. Though it is shown that computer assisted surgery (CAOS) improves the anteroposterior (AP) alignment in TKA, it is still unknown whether navigation helps in finding the accurate rotation or even improving rotation. Therefore the aim of our study was to evaluate the postoperative femoral component rotation on computed tomography (CT) with the intraoperative data of the navigation system. In 20 navigated TKAs the difference between the intraoperative stored rotation data of the femoral component and the postoperative rotation on CT was measured using the condylar twist angle (CTA). This is the angle between the epicondylar axis and the posterior condylar axis. Statistical analysis consisted of the intraclass correlation coefficient (ICC) and Bland-Altman plot. The mean intraoperative rotation CTA based on CAOS was 3.5° (range 2.4–8.6°). The postoperative CT scan showed a mean CTA of 4.0° (1.7–7.2). The ICC between the two observers was 0.81, and within observers this was 0.84 and 0.82, respectively. However, the ICC of the CAOS CTA versus the postoperative CT CTA was only 0.38. Though CAOS is being used for optimising the position of a TKA, this study shows that the (virtual) individual rotational position of the femoral component using a CAOS system is significantly different from the position on a postoperative CT scan

RD20, a stress-inducible caleosin, participates in stomatal control, transpiration and drought tolerance in Arabidopsis thaliana

UMR BPMP; UMR LEPSEInternational audiencePlants overcome water deficit conditions by combining molecular, biochemical and morphological changes. At the molecular level, many stress-responsive genes have been isolated, but knowledge of their physiological functions remains fragmentary. Here, we report data for RD20, a stress-inducible Arabidopsis gene that belongs to the caleosin family. As for other caleosins, we showed that RD20 localized to oil bodies. Although caleosins are thought to play a role in the degradation of lipids during seed germination, induction of RD20 by dehydration, salt stress and ABA suggests that RD20 might be involved in processes other than germination. Using plants carrying the promoter RD20::uidA construct, we show that RD20 is expressed in leaves, guard cells and flowers, but not in root or in mature seeds. Water deficit triggers a transient increase in RD20 expression in leaves that appeared predominantly dependent on ABA signaling. To assess the biological significance of these data, a functional analysis using rd20 knock-out and overexpressing complemented lines cultivated either in standard or in water deficit conditions was performed. The rd20 knock-out plants present a higher transpiration rate that correlates with enhanced stomatal opening and a reduced tolerance to drought as compared with the wild type. These results support a role for RD20 in drought tolerance through stomatal control under water deficit conditions

Specific TCP transcription factors interact with and stabilize PRR2 within different nuclear sub-domains

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Does the activation of poly (ADP-ribose) synthetase mediate tissue injury in the sepsis induced by cecal ligation and puncture?

Poly (ADP-ribose) synthetase (PARS) is a DNA protective enzyme activated by single-strand breakage. It is suspected that exaggerated PARS activation related to biochemical stress by reactive oxygen and nitrogen species contributes to cellular injury in sepsis. The main hypothesis is that PARS activation leads to massive ATP and NAD consumption and consequent cellular energy depletion. The PARS inhibitor 3-amino-benzamide (3AB) is protective in rodents challenged with either endotoxin or intraperitoneal zymozan. The present experiment was designed to test the effect of 3AB in a more clinically relevant model of sepsis, namely polymicrobial sepsis induced by cecal ligature and puncture (CLP). Adult male Wistar rats were anesthetized, instrumented with catheters in the jugular vein and in the carotid artery, and then randomized into three groups: Sham (no laparotomy, n = 13), CLP (n = 15), and CLP/3AB (n = 18). All animals were allowed to recover and they received a continuous intravenous infusion of saline (20 mL/kg/h) and fentanyl (20 microg/kg/h). 3AB was administered to the CLP/3AB group as an intravenous bolus (10 mg/kg) followed by a continuous intravenous infusion (10 mg/kg/h). After 24 h, blood was drawn for the determination of biological indicators of organ injury. Rats were then anesthetized and biopsies of the liver were quickly frozen into liquid nitrogen for the subsequent determination of NAD and ATP levels. Further organ samples were collected for the assay of myeloperoxidase (MPO) to indicate tissue infiltration by leukocytes, and nitrotyrosine to indicate the level of biochemical stress by reactive nitrogen species. Twenty-four-hour mortality was 0/13 (Sham), 1/15 (CLP), and 5/18 (CLP/3AB; p = NS). In the surviving rats, CLP induced a clear elevation of liver enzymes, bilirubin, and pancreatic lipase, but not creatinine in the plasma, as well as a marked increase of MPO activity in liver, jejunum, and lung, but not kidney or heart. None of these variables was affected by treatment with 3AB. Furthermore, CLP did not cause depletion of NAD or ATP in the liver, nor any change in the nitrotyrosine content of any organ. These data argue against a general role of PARS activation in the pathogenesis of sepsis-induced tissue injury

PRR2, a pseudo-response regulator, promotes salicylic acid and camalexin accumulation during plant immunity

Calcium signalling mediated by Calmodulin (CaM) and calmodulin-like (CML) proteins is critical to plant immunity. CaM and CML regulate a wide range of target proteins and cellular responses. While many CaM-binding proteins have been identified, few have been characterized for their specific role in plant immunity. Here, we report new data on the biological function of a CML-interacting partner, PRR2 (PSEUDO-RESPONSE REGULATOR 2), a plant specific transcription factor. Until now, the physiological relevance of PRR2 remained largely unknown. Using a reverse genetic strategy in A. thaliana, we identified PRR2 as a positive regulator of plant immunity. We propose that PRR2 contributes to salicylic acid (SA)-dependent responses when challenged with the phytopathogenic bacterium Pseudomonas syringae. PRR2 is transcriptionally upregulated by SA and P. syringae, enhances SA biosynthesis and SA signalling responses; e.g. in response to P. syringae, PRR2 induces the production of SA and the accumulation of the defence-related protein PR1. Moreover, PRR2 overexpressing lines exhibit an enhanced production of camalexin, a phytoalexin that confers enhanced resistance against pathogens. Together, these data reveal the importance of PRR2 in plant immune responses against P. syringae and suggest a novel function for this particular plant specific transcription factor in plant physiology

Pertinence et reproductibilité de l’interprétation de l’IRM dans les luxations et les lésions ligamentaires bicroisées du genou

International audienceIntroductionAprès luxations et lésions ligamentaires bicroisées du genou, l’évaluation clinique des lésions des parties molles est difficile et une IRM est généralement réalisée.HypothèseL’IRM est un examen fiable permettant un bilan précis et reproductible des lésions des parties molles après luxation ou lésion ligamentaire bicroisée du genou.Patients et méthodeQuarante patients présentant des lésions ligamentaires bicroisées du genou ont été inclus dans cette étude prospective multicentrique. Tous ont eu une IRM du genou dans les 48 heures suivant l’accident. Trente-quatre patients ont été traités chirurgicalement. Une fiche d’interprétation standardisée de l’IRM a été créée. Cette fiche comprenait 17 items. La reproductibilité intra-observateur a été évaluée en comparant les résultats des interprétations de cinq chirurgiens réalisées à deux reprises à trois semaines d’intervalle. La reproductibilité inter-observateurss a été évaluée en comparant les résultats des interprétations de 40 IRM réalisées par trois binômes de chirurgiens. La pertinence des interprétations IRM était réalisée en comparant les résultats des chirurgiens à ceux d’un radiologue et avec les données des comptes rendus opératoires.RésultatsLa concordance globale intra-observateur et inter-observateurss était faible. En comparant les résultats du chirurgien à ceux du radiologue et des données opératoires, la concordance était faible.DiscussionAprès luxation ou lésion ligamentaire bicroisée du genou, un diagnostic précis est nécessaire. Notre étude met en évidence le manque de précision et de reproductibilité des interprétations par IRM de façon isolée pour le diagnostic lésionnel topographique. L’IRM doit être intégrée dans une évaluation complète avec un examen clinique précis et des radiographies de stress

Relevancy and reproducibility of magnetic resonance imaging (MRI) interpretation in multiple-ligament injuries and dislocations of the knee

International audienceIntroduction: After multiple-ligament injuries and dislocations of the knee, clinical assessment of the soft tissues is difficult and MRI is generally performed. Hypothesis: MRI is a reliable examination, providing a precise and reproducible assessment of soft-tissue lesions after multiple-ligament injuries or dislocations of the knee. Materials and methods: Forty patients presenting multiple-ligament lesions of the knee were included in this multicenter prospective study. All had an MRI of the knee in the 48. h following their accident. Thirty-four patients were treated surgically. A 17-item standardized interpretation guide was created. Intraobserver reproducibility was assessed by comparing the interpretations of five surgeons at two different times 3 weeks apart. Interobserver reproducibility was evaluated by comparing the results of the interpretations of 40 MRIs performed by three pairs of surgeons. The relevance of the MRI interpretations was determined by comparing the results of the surgeons to those of a radiologist and with the data from the surgical reports. Results: The overall intraobserver and interobserver agreement was low. Comparing the surgeon's results with the radiologist's results and the surgical data, the agreement was low. Discussion: After multiple-ligament injuries and dislocations of the knee, a precise diagnosis is necessary. This study provides an isolated demonstration of the lack of precision and reproducibility of MRI interpretations for the diagnosis of the lesion's topography. MRI should be integrated into a complete assessment with a precise clinical exam and stress X-rays. Level of evidence: Level IV, prospective case-control study