Demonstration of a strong Rydberg blockade in three-atom systems with anisotropic interactions.

We study the Rydberg blockade in a system of three atoms arranged in different two-dimensional geometries (linear and triangular configurations). In the strong blockade regime, we observe high-contrast, coherent collective oscillations of the single excitation probability and an almost perfect van der Waals blockade. Our data are consistent with a total population in doubly and triply excited states below 2%. In the partial blockade regime, we directly observe the anisotropy of the van der Waals interactions between |nD> Rydberg states in the triangular configuration. A simple model that only uses independently measured two-body van der Waals interactions fully reproduces the dynamics of the system without any adjustable parameter. These results are extremely promising for scalable quantum information processing and quantum simulation with neutral atoms.

Direct measurement of the van der Waals interaction between two Rydberg atoms.

We report the direct measurement of the van der Waals interaction between two isolated, single Rydberg atoms separated by a controlled distance of a few micrometers. Working in a regime where the single-atom Rabi frequency for excitation to the Rydberg state is comparable to the interaction, we observe partial Rydberg blockade, whereby the time-dependent populations of the various two-atom states exhibit coherent oscillations with several frequencies. Quantitative comparison of the data with a simple model based on the optical Bloch equations allows us to extract the van der Waals energy, and observe its characteristic C6/R6 dependence. The measured C6 coefficients agree well with ab initio calculations, and we observe their dramatic increase with the principal quantum number n of the Rydberg state.

Isokinetic rotator muscles fatigue in glenohumeral joint instability before and after Latarjet surgery: a pilot prospective study.

We aimed to analyze the changes in isokinetic internal (IR) and external (ER) rotator muscles fatigue (a) in patients with non-operated recurrent anterior instability, and (b) before and after shoulder surgical stabilization with the Bristow-Latarjet procedure. Thirty-seven patients with non-operated unilateral recurrent anterior post-traumatic instability (NG) were compared with 12 healthy subjects [control group (CG)]. Twenty patients with operated recurrent anterior instability group (OG) underwent isokinetic evaluation before and 3, 6, and 21 months after Bristow-Latarjet surgery. IR and ER muscles strength was evaluated with Con-Trex® dynamometer, with subjects seated and at a 45° shoulder abduction angle in scapular plane. IR and ER muscle fatigue was determined after 10 concentric repetitions at 180° · s(-1) through the fatigue index, the percent decrease in performance (DP), and the slope of peak torque decrease. There were no differences in rotator muscles fatigue between NG and CG. In OG, 3 months post-surgery, IR DP of operated shoulder was significantly (P < 0.001) higher than presurgery and 6 and 21 months post-surgery. Rotator muscles fatigability was not associated with recurrent anterior instability. After surgical stabilization, there was a significantly higher IR fatigability in the operated shoulder 3 months post-surgery, followed by recovery evidenced 6 months post-surgery and long-term maintenance over 21 months.

Immune checkpoint inhibitors-induced systemic capillary leak syndrome: A report of two cases.

INTRODUCTION: The occurrence of systemic capillary leak syndrome under immune checkpoint inhibitors has seldom been reported in the literature. OBSERVATION: We report two cases of systemic capillary leak syndrome that occurred with nivolumab (anti-PD-1 antibody) for one, and with an anti-PD-1/CTLA-4 bi-specific antibody for the other. Patients presented with anasarca, hypoalbuminemia, acute kidney injury and, in one case, circulatory collapse. Immune checkpoint inhibitor causality was retained in the lack of evidence for other causes of secondary capillary leak syndrome or for an idiopathic form. The symptoms resolved after a few days of supportive measures (associated with glucocorticoids in one case). DISCUSSION: A high index of suspicion is required for the diagnosis of immune checkpoint inhibitors-induced systemic capillary leak syndrome because its presentation may differ from that of the idiopathic form. Activated CD8+ T-cells play a prominent role in the occurrence of immune checkpoint inhibitors-induced capillary leakage via their cytolytic action on the vascular endothelium. Treatment relies on supportive measures and discontinuation of the immune checkpoint inhibitor while the place of immunomodulatory drugs remains to be defined.

Recovery of rotators strength after Latarjet surgery.

The purposes of this study were to prospectively determine changes in rotator cuff strength before and after surgical shoulder stabilization by Bristow-Latarjet procedure and to better estimate time needed for rotator cuff strength recovery. 20 patients with recurrent anterior posttraumatic shoulder dislocation underwent internal (IR) and external (ER) rotator isokinetic evaluation before and 3, 6 and 21 months after Bristow-Latarjet surgery. In a seated position with 45° of shoulder abduction in the scapular plane, both shoulders were evaluated concentrically with a Con-Trex® isokinetic dynamometer at 180°âˆ™s (- 1), 120°âˆ™s (- 1) and 60°âˆ™s (- 1). 3 months post-surgery, IR and ER strength of the operated shoulder were significantly lower than before surgery (- 28 ± 20% for IR, - 17 ± 17% for ER) (P<0.05). At 6 and 21 months post-surgery, IR and ER strength were comparable to strength before surgery; strength recovery is seen at 6 months post-surgery with long-term maintenance at 21 months. Given the weakness 3 months post-surgery, return to sports (including overhead and contact sports) should be discussed, and 6 months post-surgery may be a better point for an athlete to resume practicing sports. Isokinetic rotator cuff strength evaluation appears to be relevant in helping to determine the need of continuing strength rehabilitation. Pre-surgical evaluation contributes to the relevance of later comparisons.

[Functional range of motion of the hip joint]. / La mobilité fonctionnelle de l'articulation de la hanche.

PURPOSE OF THE STUDY: The functional mobility of a joint represents the range of motion healthy individuals require to fulfill everyday life tasks. Oscillation angle corresponds to the entire range of motion that can be achieved by the joint. Wedge opening and direction are the characteristic features. We describe the characteristics of functional mobility of the hip joint in healthy subjects. MATERIAL AND METHODS: Hip motion was analyzed in twelve healthy subjects aged 22 to 25 years. The three dimensional analysis used the Motion Analysis System (Motion Analysis Corporation, Santa Rosa, CA) at a frequency of 60 Hz. MatLab software was used to modelize a prosthesis and determine the oscillation angle and its direction as a function of implant position and head-to-neck ratio. After determining the hip center for each individual subject, the range of motion necessary to complete a task was given by the maximal angle along each anatomic axis needed to reach a given position in comparison with the resting position. The following tasks were studied: sit to stand motion, lifting weight from a squatting position, reaching the ground with both legs abducted in extension, walking, ascending and descending stairs, getting on a bicycle, sitting cross-legged, cutting toenails. Whether or not the task could be achieved with the prosthetic conformation was then determined. RESULTS: Each task was described as a combination of motion in the three anatomic axes. Lifting weight from a squatting position combined flexion (110 degrees), abduction (9 degrees) and external rotation (18 degrees) with a standard deviation of 9 degrees. For a given task, only a few combinations of femoral and acetabular orientations were compatible with completion of that task. Combining the motions required for several tasks diminished the possible orientations for prosthetic positioning. DISCUSSION: Analyzing the motion required for these tasks shows the maximal range of motion involved in each direction. There was very little variability among healthy subjects. These results are in agreement with other values determined with other methods. Compensatory mechanisms used by disabled people to complete different tasks were not taken into consideration. The effects of changing either the head-to-neck ratio or implant position are discussed in relation to completion of a given task.

Translation and validation of the French version of the Western Ontario Shoulder Instability Index (WOSI): WOSI-Fr.

INTRODUCTION: The Western Ontario Shoulder Instability Index (WOSI) is a specific self-administered questionnaire measuring the functional impact on patients with chronic glenohumeral instability. In its English version, it is valid, reliable, and sensitive to change. The objective of the present study was to provide a linguistic and cross-cultural adaptation of the original version of the WOSI to French and to assess the metrologic properties of this version in patients with chronic shoulder instability. MATERIAL AND METHODS: The WOSI was translated and adapted both linguistically and culturally to French (WOSI-Fr) according to current guidelines. The metrologic properties of the WOSI-Fr were analyzed in the following groups - unoperated patients with chronic shoulder instability (UOG), operated patients with chronic shoulder instability (OG), patients with instability (TotG=UOG+OG), and control patients (ContG) - through analysis of the construct validity by comparing the WOSI-Fr with the Rowe, Walch-Duplay, QuickDASH, and VAS pain scores, and through analysis of reliability through the reproducibility of internal consistency. RESULTS: The WOSI-Fr version was established and then accepted by an expert group (n=7). There was a statistically significant correlation between the WOSI and the different pain and function scores for TotG, OG, and UOG (except with the VAS pain score and the QuickDASH for UOG). Reproducibility (n=27) was good: the ICC value for the total score was 0.88 (95% CI, 0.47-0.98), varying from 0.80 to 0.94 according to the four domains of the WOSI-Fr, and from 0.70 to 0.94 for the different items separately. For TotG, Cronbach's alpha was 0.953, the SEM and the MDC were 120.2 (5.7%) and 333 (15.9%), respectively. CONCLUSION: The French version of the WOSI (WOSI-Fr) is available, adapted linguistically and culturally, valid, and reliable. We recommend using it in following up patients with shoulder instability. LEVEL OF EVIDENCE: Prospective, level 2.

[Iliopsoas impingement in 12 patients with a total hip arthroplasty]. / Le conflit ilio-psoas - prothèse dans les arthroplasties totales de hanche douloureuses.

PURPOSE OF THE STUDY: We report 12 cases of iliopsoas impingement, an under-recognized cause of hip pain in total hip arthroplasty patients. MATERIAL AND METHODS: Between January 1998 and October 2000, we diagnosed 12 cases of iliopsoas impingement among 280 total hip arthroplasty patients with hip pain (4.3%). Our population was composed of 9 women and 3 men aged 62 to 80 years (mean 72 years). Nine patients had a first intention arthroplasty and 3 had a revision prosthesis. Delay from implantation to diagnosis of impingement ranged from 6 months to 5 years. Common cases of pain after hip arthroplasty, infection, loosening, were ruled out in all cases. A standard x-ray series including an AP view of the pelvis, an AP view of the hip and a surgical false-lateral view of the hip as well as a CT scan were obtained when iliopsoas impingement was suspected. The CT series extended from the lower part of the acetabulum through the fixation screws. RESULTS: Pain had been observed immediately after implantation in 10 cases (83%) and in 2 cases (17%) 3 to 5 years later. These patients did not have to use crutches when pain started to develop. Pain projected anteriorly and was always exaggerated when moving from the sitting position to the upright position and when going up stairs. In one patient, palpation revealed a mass in the groin that corresponded to a massive iliopsoas bursitis. Two non-pathognomonic physical signs were found in all cases: groin pain induced by active flexion against force in the lateral reclining position and at hip extension, and pain in the dorsal reclining position at deflexion of the hip, starting at 45 degrees. The standard AP views showed evidence of defective anteversion of 4 press fit cups, 1 off-centered screwed cup and 3 oversized cups. The CT scan demonstrated that the impingement involved the anterior border of the cup applied against the iliopsoas tendon in 8 cases either due to anterior uncovering in a dysplasic hip or anterior cup overhang. In 4 cases the cup fixation screws protruded anteriorly in front of the ilion and came in contact with the posterior aspect of the iliopsoas muscle. A bursitis had developed in 50% of the cases. DISCUSSION: When infection and loosening have been ruled out, hip pain after total hip arthroplasty would suggest a possible impingement of the acetebular component on the iliopsoas muscle due to defective anteversion or centering, the use of oversized cups, and/or the use of fixation screws. We emphasize the importance of a correct position for the cup to avoid an overhanging anterior border and discuss the use of screwed cups for primary total hip arthroplasty and of oversized cups for revision procedures.

[Vascular risk and total hip arthroplasty]. / Risque vasculaire et arthroplastie totale de hanche.

PURPOSE OF THE STUDY: Though exceptional, there is a real risk of vascular complications during total hip arthroplasty procedures. The gravity of these iatrogenic accidents results from their high mortality (7%) and possible functional sequelae (19%). MATERIAL AND METHOD: We report a retrospective multicenter study of 14 vascular complications, six of which occurred during revision surgery for total hip arthroplasty. We assessed risk factors and identified situations of major risk related to acetabular revision: intrapelvic dislocation, protrusion with no bony barrier, and presence of intrapelvic foreign bodies. We advocate the retroperitoneal approach for acetabular revision in case of intrapelvic dislocation or anomalous vessel size or trajectory on the preoperative arteriography. This approach allows ablation of the implants under visual control of the iliac vessels. RESULTS AND DISCUSSION: A careful preoperative work-up is essential to avoid arterial or venous injury. A perfect knowledge of the vessel trajectories and their projection on the acetabulum is crucial. Indeed, such vascular complications are never expected and transform a well-programmed functional procedure into an emergency procedure with the inherent risks. We recall that such accidents may be expressed well after closing and the importance of careful surveillance before, during and after the surgical procedure.

[Plaque variant of trichoblastic fibroma]. / Fibrome trichoblastique en plaque.

BACKGROUND: Tricoblastic fibroma is a rare benign skin tumor originating in the hair follicle. There are two clinical presentations: nodular and plaque variants. The plaque variant is almost exclusively located on the face with deep tissue infiltration. CASE REPORT: A 38-year-old man presented with a 2 cm diameter cutaneous plaque located on the right cheek. It had first been noted by the patient 3 years earlier and had enlarged slowly. On examination, the plaque was well defined, yellowish and slightly indurated. The first clinical diagnosis was basal cell carcinoma and the plaque was removed. Histology provided the diagnosis of trichoblastic fibroma. The patient remains well, with no evidence of recurrence, 10 months after excision. DISCUSSION: Trichoblastoma is an inclusive term for all benign cutaneous neoplasms that are mostly composed of follicular germinative cells. According to Altman, the plaque variant of trichoblastic fibroma is a poorly circumscribed neoplasm, particularly at its lateral and deep margins. This author also states that mitotic figures are more numerous in the plaque variant of trichoblastic fibroma and considers this clinical variant as a low-grade follicular malignancy.

[Unstable pelvic ring fracture: osteosynthesis of the posterior lesion by percutaneous sacroiliac fixation]. / Fractures instables de l'anneau pelvien: ostéosynthèse de la lésion postérieure par vissage sacro-iliaque percutané

PURPOSE OF THE STUDY: We report our experience with percutaneous sacroiliac screwing for unstable pelvic ring fracture. MATERIAL AND METHODS: Twenty unstable pelvic ring fractures with sacroiliac disjunction (9 cases), trans-sacral fracture (9 cases), or bilateral posterior fractures (5 cases) were managed with percutaneous sacroiliac fixation using 1 or 2 screws. There was also pubic disjunction in 7 cases, managed by osteosynthesis in 5 cases. No fixation of fractures of one or both of the obturator rings, present in 13 cases, was attempted. The posterior screwing was performed under fluoroscopic guidance in 15 cases and computed tomographic guidance in 5. RESULTS: There were no infectious or neurological complications. Radiographically, anatomic reduction of the posterior fracture was achieved in 10 cases. A vertical ascension persisted in 4 patients and a rotation in 6. Radiographic results were correlated with delay to surgery: correction of the vertical displacement was achieved in 80% of the patients operated before five days and in 55% of the others. Two patients experienced a secondary displacement. There was no cases of nonunion of either the anterior or posterior fracture. Follow-up was available for 14 patients (2 patients died and follow-up was too short for 4). The mean Majeed score was 92/100 and none of the patients experienced anterior pain. Three patients had moderate pain in the sacroiliac area. DISCUSSION: The ventral position appears to be best adapted for percutaneous sacroiliac screwing but can be contraindicated by concomitant lesions. We prefer fluoroscopic guidance for these emergency procedures. Two views, ascending and descending, appear sufficient. The better stability provided by two screws can be achieved under computed tomographic guidance without risk of neurovascular damage. CONCLUSION: Percutaneous sacroiliac screwing is a good management strategy for unstable pelvic ring fractures with little risk of morbidity.

[Phenylbutazone-induced sialadenitis fever simulating angioedema]. / Sialadénite à la phénylbutazone simulant un oedème de Quincke.

BACKGROUND: Drug-induced sialadenitis is uncommon and unrecognized. Drugs such as nitrofurantoïn, nifedipine and methimazole have been reported to induce sialadenitis. However, phenylbutazone and oxyphenbutazone are the most frequently implicated agents. We describe a case of phenylbutazone-induced parotitis and submaxillitis with cutaneous and hepatic involvement. CASE REPORT: A 51 year-old woman who had received phenylbutazone for the past 6 days was hospitalized for diagnosis of Quincke's oedema. Clinical examination in fact revealed bilateral parotitis and submaxillitis. The patient had contracted mumps in infancy. Improvement was noticed 8 days after stopping the drug and treatment by glucocorticosteroid. Nevertheless a pruritic eruption with fever appeared. Laboratory data showed leukocytosis with neutrophilia, ESR of 75 mm/hr, hepatic cholestasis and cytolysis. Infectious and autoimmune causes were ruled out. The eruption spontaneously disappeared after 5 days. Laboratory studies 3 weeks later were normal. DISCUSSION: Quincke's edema diagnosis had been established too fast on "allergic past history" and patient interrogation. Complete clinical examination revealed the correct diagnosis of sialadenitis. This observation shows similarities with other publications: unbearable xerostomia appearing before sialadenitis and with a long course, parotitis with sub-maxillitis, 6 days delay after the first administration of phenylbutazone before fever, local evolution without complication, inflammatory biological syndrome with neutrophilia and absence of infectious cause. Pruritic maculo-papulous eruption and biological hepatic abnormalities are however rare. An hypersensibility mechanism is discussed.

Relationship between strength and functional indexes (Rowe and Walch-Duplay scores) after shoulder surgical stabilization by the Latarjet technique.

INTRODUCTION: The rotator cuff muscles help stabilize the glenohumeral joint. Postoperative recovery of rotator cuff muscle strength appears to be an important factor for optimal joint stabilization and the resumption of professional and/or sports activities. OBJECTIVE: To study the relationship between internal rotator (IR) and external rotator (ER) muscle strength, shoulder function and the resumption of sports activities (as typically evaluated with functional scores) following surgical stabilization with the Bristow-Latarjet procedure in cases of chronic shoulder instability. PATIENTS AND METHODS: Twenty patients with anterior, post-traumatic, chronic shoulder instability were included prospectively in a cohort study. The Rowe and Walch-Duplay functional scores were rated for the operated shoulder and the isokinetic IR and ER peak torque values were evaluated with a Con-Trex(®) dynamometer before surgery and then 3, 6 and 21 months afterwards. The isokinetic evaluation was performed (at 180°/s, 120°/s and 60°/s) in the seated position, with the arms in 45° of abduction and 30° of antepulsion in the plane of the scapula. RESULTS: There were no significant postoperative correlations between shoulder function (as judged by the Rowe and Walch-Duplay scores) and IR or ER muscle strength. CONCLUSION: This study did not provide evidence for a correlation between IR and ER muscle strength and functional scores after surgical stabilization of the shoulder. However, it is necessary to objectively measure the rotator cuff strength recovery to adequate the strengthening of rotator muscle prior to the resumption of sports activities. Isokinetic strength assessment may thus be a valuable decision support tool for the resumption of sports activities and would complement the functional scores studied here.

Improvements to selective refocusing phased (SERFph) experiments.

Selective refocusing experiments are very powerful for extracting proton-proton couplings one by one. However we demonstrate in the present work that various spectral artefacts are produced by the initial sequence and we show that the combined addition of a refocusing pi pulse and a zero-quantum filter greatly improves the experimental sensitivity, and moreover leads to observation of pure absorption lineshapes in the resulting phased 2D spectrum. These developments are applied to the differentiation of enantiomers dissolved in a chiral liquid crystal.

Plasma exchange: an important part of the therapeutic procedure in a small child with autoimmune hemolytic anemia.

The case history of a child with autoimmune hemolytic anemia with complement activating warm antibodies of the pdl type is presented. This child also had giant cell hepatitis. Although plasma exchange is not curative in such a patient, the removal of antibodies and bilirubin by means of plasma exchange has alleviated the patient's condition on two occasions (at age 19 and 33 months respectively), and has permitted the institution of effective immunosuppression. A technique for plasma exchange is described, which by use of plasma filters and the usual hemodialysis equipment allows to safely perform the procedure in any pediatric hemodialysis unit. Its use in this patient stresses the technical practicability even in very young children. It is suggested that plasma exchange, if indicated, should be considered more often as part of a therapeutic concept.