Altérations anatomopathologiques liées au traitement par cerclage des globes oculaires atteints de décollement de rétine [Histological changes related to scleral buckling for treatment of retinal detachment].

Treatment of retinal detachment frequently uses biocompatible materials to obtain scleral buckling. These materials are not devoid of consequences on surrounding tissues. In 3 eyes enucleated for failure of surgical treatment using scleral buckling materials, the changes prompted by episcleral implants could be observed. The sclera underwent both an inversion of its curvature and a reduction of its thickness under the material, as well as an encapsulation of the material was observed. While a silicone sponge was used in part to encircle one of these eyes, its capsular inner surface was regular and smooth. In contrast, hydrogel implants used in the three eyes showed a peripheral fragmentation prompting in two of them a typical foreign body giant cell granulomatous reaction. Changes in scleral curvature and scleral thinning were observed reflecting the consequences of the buckling procedure. The capsule formation occurred as it does for any nonabsorbable matérial implanted in tissues. Degradation and fragmentation of the hydrogel material suscitated a granuloma in response to fragments. These hydrogel specific changes should be recognized on microscopic examination of slides of either capsule or eyes previously in contact with this implanted material. They attested of the instability of hydrogel after implantation.

Anatomic shoulder arthroplasty: consequences of humeral head malposition

Purpose Third generation anatomic total shoulder prostheses offer a wide range of adaptability (size, thickness, retroversion and offset of the humeral head, cervico-diaphyseal angle) in order to reproduce anatomy and biomechanics of the shoulder as normal as possible. The large variability of the implants may also induce malposition. Our goal was to analyse the consequences of a humeral head malposition, which is one of the most frequent placement errors. Material and Methods A 3D finite element model of the glenohumeral joint, including the rotator cuff muscles and the deltoid, was used with the Aequalis anatomic prosthesis. Active abduction was simulated. Three humeral head placements were compared : anatomic positioning (A), 5 mm inferior positioning (B), 5 mm superior positioning (C). The effect of humeral head malposition was evaluated through the following quantities : the range of motion free of impingements, the glenohumeral contact pattern, and the stress within the polyethylene and the cement. Results Inferior positioning (B) of the humeral head produced a superior impingement before 90° of abduction, an inferior eccentric contact point on the glenoid, and 165% increase of cement stress. Superior positioning (C) of the humeral head produced a postero-superior eccentric contact point on the glenoid, 300% increase of glenohumeral contact pressure, 450% increase of polyethylene stress, and 207% increase of cement stress. Conclusion Malposition of the humeral head of anatomic prostheses induces biomechanical consequences that may preclude the glenoid survival. Particular attention must be paid to reproduce the humeral anatomy as normal as possible.

Limb-girdle Muscular Dystrophy Type 2A Can Result from Accelerated Autoproteolytic Inactivation of Calpain 3.

Loss-of-function mutations in calpain 3 have been shown to cause limb-girdle muscular dystrophy type 2A (LGMD2A), an autosomal recessive disorder that results in gradual wasting of the muscles of the hip and shoulder areas. Due to the inherent instability of calpain 3, recombinant expression of the full-length enzyme has not been possible, making in vitro analysis of specific LGMD2A-causing mutations difficult. However, because calpain 3 is highly similar in amino acid sequence to calpain 2, the recently solved crystal structure of full-length, Ca2+-bound, calpastatin-inhibited rat calpain 2 has allowed us to model calpain 3 as a Ca2+-bound homodimer. The model revealed three distinct areas of the enzyme that undergo a large conformational change upon Ca2+-binding. Located in these areas are several residues that undergo mutation to cause LGMD2A. We investigated the in vitro effects of six of these mutations by making the corresponding mutations in rat calpain 2. All six mutations examined in this study resulted in a decrease in enzyme activity. All but one of the mutations caused an increased rate of autoproteolytic degradation of the enzyme as witnessed by SDS-PAGE, indicating the decrease in enzyme activity is caused, at least in part, by an increase in the rate of autoproteolytic degradation. The putative in vivo effects of these mutations on calpain 3 activity are discussed with respect to their ability to cause LGMD2A.

Paper money and national distress: William Huskisson and the early theories of credit, speculation and crises

This paper examines the explanation of commercial crises offered by William Huskisson in 1810 in the wake of the debate on the Bullion Report. Huskisson argued that the suspension of convertibility made it possible to extend issues of paper currency beyond its proper limits. Such an expansion, being in the interest of all parties concerned, would actually take place and stimulate excessive speculations, which would eventually prove unsustainable and bring generalized ruin and distress. Although some elements of this explanations were not new (having been anticipated by writers sucha as James Currie in 1793, William Roscoe in 1793, William Anderson in 1797 and an anonymous in 1796), Huskisson's explanation is more systematic and better organized, and his emphasis on the endogenous character of the crisis and on the instability of the dynamics of trade and credit makes it an interesting foreshadower of the theories of crises that were advanced half a century later.

Optimal 3-T MRI for depiction of the finger A2 pulley: comparison between T1-weighted, fat-saturated T2-weighted and gadolinium-enhanced fat-saturated T1-weighted sequences

OBJECTIVE: To compare three spin-echo sequences, transverse T1-weighted (T1WI), transverse fat-saturated (FS) T2-weighted (T2WI), and transverse gadolinium-enhanced (Gd) FS T1WI, for the visualisation of normal and abnormal finger A2 pulley with magnetic resonance (MR) imaging at 3 tesla (T). MATERIALS AND METHODS: Sixty-three fingers from 21 patients were consecutively investigated. Two musculoskeletal radiologists retrospectively compared all sequences to assess the visibility of normal and abnormal A2 pulleys and the presence of motion or ghost artefacts. RESULTS: Normal and abnormal A2 pulleys were visible in 94% (59/63) and 95% (60/63) on T1WI sequences, in 63% (40/63) and 60% (38/63) on FS T2WI sequences, and in 87% (55/63) and 73% (46/63) on Gd FS T1WI sequences when read by the first and second observer, respectively. Motion and ghost artefacts were higher on FS T2WI sequences. Seven among eight abnormal A2 pulleys were detected, and were best depicted with Gd FS T1WI sequences in 71% (5/7) and 86% (6/7) by the first and the second observer, respectively. CONCLUSION: In 3-T MRI, the comparison between transverse T1WI, FS T2WI, and Gd FS T1WI sequences shows that transverse T1WI allows excellent depiction of the A2 pulley, that FS T2WI suffers from a higher rate of motion and ghost artefacts, and transverse Gd FS T1WI is the best sequence for the depiction of abnormal A2 pulley.

Habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus (Müller, 1774)

Our objective is to evaluate the habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus. In the first phase, snails was collected at 12 sites. This sampling sites presented a degree of organic input. In the second phase 33 sampling sites were chosen, covering a variety of lotic and lentic environments. The snail species found at Guapimirim, state of Rio de Janeiro, displayed a marked habitat preference, specially in relation to the physical characteristics of each environment. Other limiting factors for snail distribution at the studied lotic environments were the water current velocity and the amount of organic matter, mainly to Physa marmorata, M. tuberculatus, and Biomphalaria tenagophila. The absence of interactions between M. tuberculatus and another snails could be associated to the distinct spatial distribution of those species and the instability of habitats. This later factor may favor the coexistence of M. tuberculatus with B. glabrata by reduction of population density. In areas of schistosomiasis transmission some habitat modification may add to the instability of the environment, which would make room for the coexistence of M. tuberculatus and Biomphalaria spp. In this way, some of the usual measures for the control of snail hosts would prevent the extinction of populations of Biomphalaria spp. by M. tuberculatus in particular habitats.

A pilot study of delayed versus immediate serial casting after botulinum toxin injection for partially reducible spastic equinus.

BACKGROUND: Serial casting is often prescribed after botulinum toxin injections to improve joint ranges of motion and to potentiate the decrease in hypertonia. The aim of this study was to compare delayed versus immediate serial casting as an adjunct to botulinum toxin therapy for partially reducible spastic equinus. METHODS: Twelve children who presented spastic equinus associated with mild gastrosoleus contracture took part. Five of them had a diagnosis of spastic diplegia, whereas 7 had a diagnosis of congenital hemiplegia. Children were randomized to immediate serial casting (same day) or delayed serial casting (4 weeks later) after botulinum toxin injection to their gastrosolei. Casts were replaced weekly for 3 weeks. RESULTS: Three children complained of pain that required recasting in the immediate casting group versus none in the delayed casting group (P = 0.08). At 3 months, there was a 27-degree improvement in the fast dorsiflexion angle (Tardieu R1) in the delayed casting group versus 17 degrees in the immediate casting group (P = 0.029). At 6 months, a 19-degree improvement persisted in the delayed group compared with 11 degrees in the immediate group (P = 0.010). CONCLUSIONS: There is a clear benefit in delaying serial casting after the injection of botulinum toxin in the recurrence of spasticity at the gastrosoleus that may also offer an advantage regarding the incidence of painful episodes associated with casting. Most importantly, reducing the recurrence of spasticity by delayed serial casting may offer the possibility of decreasing the frequency of botulinum toxin reinjections.

Influence of the ankle arthropathies on the 3D kinematics of the lower limbs during gait: analysis with an ambulatory system.

Introduction: Ankle arthropathy is associated with a decreased motion of the ankle-hindfoot during ambulation. Ankle arthrodesis was shown to result in degeneration of the neighbour joints of the foot. Inversely, total ankle arthroplasty conceptually preserves the adjacent joints because of the residual mobility of the ankle but this has not been demonstrated yet in vivo. It has also been reported that degenerative ankle diseases, and even arthrodesis, do not result in alteration of the knee and hip joints. We present the preliminary results of a new approach of this problem based on ambulatory gait analysis. Patients and Methods: Motion analysis of the lower limbs was performed using a Physilog® (BioAGM, CH) system consisting of three-dimensional (3D) accelerometer and gyroscope, coupled to a magnetic system (Liberty©, Polhemus, USA). Both systems have been validated. Three groups of two patients were included into this pilot study and compared to healthy subjects (controls) during level walking: patients with ankle osteoarthritis (group 1), patients treated by ankle arthrodesis (group 2), patients treated by total ankle prosthesis (group 3). Results: Motion patterns of all analyzed joints over more than 20 gait cycles in each subject were highly repeatable. Motion amplitude of the ankle-hindfoot in control patients was similar to recently reported results. Ankle arthrodesis limited the motion of the ankle-hindfoot in the sagittal and horizontal planes. The prosthetic ankle allowed a more physiologic movement in the sagittal plane only. Ankle arthritis and its treatments did not influence the range of motion of the knee and hip joint during stance phase, excepted for a slight decrease of the hip flexion in groups 1 and 2. Conclusion: The reliability of the system was shown by the repeatability of the consecutive measurements. The results of this preliminary study were similar to those obtained through laboratory gait analysis. However, our system has the advantage to allow ambulatory analysis of 3D kinematics of the lower limbs outside of a gait laboratory and in real life conditions. To our knowledge this is a new concept in the analysis of ankle arthropathy and its treatments. Therefore, there is a potential to address specific questions like the difficult comparison of the benefits of ankle arthroplasty versus arthrodesis. The encouraging results of this pilot study offer the perspective to analyze the consequences of ankle arthropathy and its treatments on the biomechanics of the lower limbs ambulatory, in vivo and in daily life conditions.

Computer-assisted cup placement techniques in total hip arthroplasty improve accuracy of placement.

Malposition of the acetabular component during hip arthroplasty increases the occurrence of impingement, reduces range of motion, and increases the risk of dislocation and long-term wear. To prevent malpositioned hip implants, an increasing number of computer-assisted orthopaedic systems have been described, but their accuracy is not well established. The purpose of this study was to determine the reproducibility and accuracy of conventional versus computer-assisted techniques for positioning the acetabular component in total hip arthroplasty. Using a lateral approach, 150 cups were placed by 10 surgeons in 10 identical plastic pelvis models (freehand, with a mechanical guide, using computer assistance). Conditions for cup implantations were made to mimic the operating room situation. Preoperative planning was done from a computed tomography scan. The accuracy of cup abduction and anteversion was assessed with an electromagnetic system. Freehand placement revealed a mean accuracy of cup anteversion and abduction of 10 degrees and 3.5 degrees, respectively (maximum error, 35 degrees). With the cup positioner, these angles measured 8 degrees and 4 degrees (maximum error, 29.8 degrees), respectively, and using computer assistance, 1.5 degrees and 2.5 degrees degrees (maximum error, 8 degrees), respectively. Computer-assisted cup placement was an accurate and reproducible technique for total hip arthroplasty. It was more accurate than traditional methods of cup positioning.

Construction and characterisation of a complete reverse genetics system of dengue virus type 3

Dengue virulence and fitness are important factors that determine disease outcome. However, dengue virus (DENV) molecular biology and pathogenesis are not completely elucidated. New insights on those mechanisms have been facilitated by the development of reverse genetic systems in the past decades. Unfortunately, instability of flavivirus genomes cloned in Escherichia coli has been a major problem in these systems. Here, we describe the development of a complete reverse genetics system, based on the construction of an infectious clone and replicon for a low passage DENV-3 genotype III of a clinical isolate. Both constructs were assembled into a newly designed yeast- E. coli shuttle vector by homologous recombination technique and propagated in yeast to prevent any possible genome instability in E. coli . RNA transcripts derived from the infectious clone are infectious upon transfection into BHK-21 cells even after repeated passages of the plasmid in yeast. Transcript-derived DENV-3 exhibited growth kinetics, focus formation size comparable to original DENV-3 in mosquito C6/36 cell culture. In vitro characterisation of DENV-3 replicon confirmed its identity and ability to replicate transiently in BHK-21 cells. The reverse genetics system reported here is a valuable tool that will facilitate further molecular studies in DENV replication, virus attenuation and pathogenesis.

Peritalar dislocations: a retrospective study of 18 cases.

The purpose of this study is to retrospectively evaluate 18 consecutive cases of peritalar dislocations referred to our department during a period of 25 years and to delineate the factors influencing long-term prognosis. There were 13 (73%) medial and 5 (27%) lateral dislocations. Six patients (33%) suffered an open injury, including 2 of 13 (15%) medial and 4 of 5 (80%) lateral dislocations. Associated fractures involving the hindfoot or forefoot were noted in 7 feet, including 3 of 5 lateral dislocation cases. Reduction was accomplished under general anesthesia; in no case was open reduction necessary. In 4 of 6 open injuries with associated fractures, temporary fixation with Kirschner wires was performed. Patients were immobilized in a plaster cast for 4 weeks, or for 6 weeks in the presence of fracture, followed by weightbearing as tolerated. At a mean follow-up of 10.2 years (range, 4 to 26 years), 10 patients (56%) showed excellent results; all had sustained a closed medial low-energy dislocation. There were 3 cases (17%) with fair results and 5 cases (28%) with poor results. Forty-five percent of patients showed a restriction of activity, a reduction of subtalar range of motion, and moderate or severe radiographic signs of hindfoot degenerative arthritis. There were no cases of talar avascular necrosis, and in no case was secondary surgery necessary. Lateral dislocation and open medial dislocations with concomitant fractures showed a greater potential for poor prognosis. The results were independent from period of cast immobilization, suggesting that 4 to 6 weeks of immobilization provides acceptable long-term results.

Detection of the movement of the humerus during daily activity.

A new ambulatory technique for qualitative and quantitative movement analysis of the humerus is presented. 3D gyroscopes attached on the humerus were used to recognize the movement of the arm and to classify it as flexion, abduction and internal/external rotations. The method was first validated in a laboratory setting and then tested on 31 healthy volunteer subjects while carrying the ambulatory system during 8 h of their daily life. For each recording, the periods of sitting, standing and walking during daily activity were detected using an inertial sensor attached on the chest. During each period of daily activity the type of arm movement (flexion, abduction, internal/external rotation) its velocity and frequency (number of movement/hour) were estimated. The results showed that during the whole daily activity and for each activity (i.e. walking, sitting and walking) the frequency of internal/external rotation was significantly higher while the frequency of abduction was the lowest (P < 0.009). In spite of higher number of flexion, abduction and internal/external rotation in the dominant arm, we have not observed in our population a significant difference with the non-dominant arm, implying that in healthy subjects the arm dominance does not lie considerably on the number of movements. As expected, the frequency of the movement increased from sitting to standing and from standing to walking, while we provide a quantitative value of this change during daily activity. This study provides preliminary evidence that this system is a useful tool for objectively assessing upper-limb activity during daily activity. The results obtained with the healthy population could be used as control data to evaluate arm movement of patients with shoulder diseases during daily activity.

Immediate Effects of Neurodynamic Sliding versus Muscle Stretching on Hamstring Flexibility in Subjects with Short Hamstring Syndrome.

Background. Hamstring injuries continue to affect active individuals and although inadequate muscle extensibility remains a commonly accepted factor, little is known about the most effective method to improve flexibility. Purpose. To determine if an isolated neurodynamic sciatic sliding technique would improve hamstring flexibility to a greater degree than stretching or a placebo intervention in asymptomatic subjects with short hamstring syndrome (SHS). Study Design. Randomized double-blinded controlled trial. Methods. One hundred and twenty subjects with SHS were randomized to 1 of 3 groups: neurodynamic sliding, hamstring stretching, and placebo control. Each subject's dominant leg was measured for straight leg raise (SLR) range of motion (ROM) before and after interventions. Data were analyzed with a 3 × 2 mixed model ANOVA followed by simple main effects analyses. Results. At the end of the study, more ROM was observed in the Neurodynamic and Stretching groups compared to the Control group and more ROM in the Neurodynamic group compared to Stretching group. Conclusion. Findings suggest that a neurodynamic sliding technique will increase hamstring flexibility to a greater degree than static hamstring stretching in healthy subjects with SHS. Clinical Relevance. The use of neurodynamic sliding techniques to improve hamstring flexibility in sports may lead to a decreased incidence in injuries; however, this needs to be formally tested.

Driven fragmentation of granular gases

The dynamics of homogeneously heated granular gases which fragment due to particle collisions is analyzed. We introduce a kinetic model which accounts for correlations induced at the grain collisions and analyze both the kinetics and relevant distribution functions these systems develop. The work combines analytical and numerical studies based on direct simulation Monte Carlo calculations. A broad family of fragmentation probabilities is considered, and its implications for the system kinetics are discussed. We show that generically these driven materials evolve asymptotically into a dynamical scaling regime. If the fragmentation probability tends to a constant, the grain number diverges at a finite time, leading to a shattering singularity. If the fragmentation probability vanishes, then the number of grains grows monotonously as a power law. We consider different homogeneous thermostats and show that the kinetics of these systems depends weakly on both the grain inelasticity and driving. We observe that fragmentation plays a relevant role in the shape of the velocity distribution of the particles. When the fragmentation is driven by local stochastic events, the longvelocity tail is essentially exponential independently of the heating frequency and the breaking rule. However, for a Lowe-Andersen thermostat, numerical evidence strongly supports the conjecture that the scaled velocity distribution follows a generalized exponential behavior f (c)~exp (−cⁿ), with n ≈1.2, regarding less the fragmentation mechanisms

Enhancement of writings on a damaged medieval manuscript using ultraviolet imaging

The Minutarium Majus, a register dating from the 13th and 14th centuries, was transferred by the paleographers responsible for its transcription to the Institute of Forensic Science of the University of Lausanne with the aim of enhancing portions of text that had become worn away and illegible. The manuscript had suffered from deterioration and damage for different unknown reasons, but most likely because of the colour instability of the ink, contaminations, storage conditions and repeated human manipulation. A total of 69 areas of text, ranging in size from just a few words to full pages, were photographically recorded under both white and ultraviolet (UV) light illumination. UV illumination observed in the visible range proved to be efficient in detecting the writings. Most of the texts could thus be successfully transcribed by the paleographers. The technique proved to be extremely useful for the exposure of damaged medieval writings.