Mannan-induced Nos2 in macrophages enhances IL-17-driven psoriatic arthritis by innate lymphocytes

Previous identification of the inducible nitric oxide synthase (NOS2) gene as a risk allele for psoriasis (Ps) and psoriatic arthritis (PsA) suggests a possible pathogenic role of nitric oxide (NO). Using a mouse model of mannan-induced Ps and PsA (MIP), where macrophages play a regulatory role by releasing reactive oxygen species (ROS), we found that NO was detectable before disease onset in mice, independent of a functional nicotinamide adenine dinucleotide phosphate oxidase 2 complex. MIP was suppressed by either deletion of Nos2 or inhibition of NO synthases with NG-nitro-l-arginine methyl ester, demonstrating that Nos2-derived NO is pathogenic. NOS2 expression was also up-regulated in lipopolysaccharide- and interferon-γ-stimulated monocyte subsets from patients with PsA compared to healthy controls. Nos2-dependent interleukin-1α (IL-1α) release from skin macrophages was essential for arthritis development by promoting IL-17 production of innate lymphoid cells. We conclude that Nos2-derived NO by tissue macrophages promotes MIP, in contrast to the protective effect by ROS.

Monitoring trabecular bone microdamage using a dynamic acousto-elastic testing method

Dynamic acousto-elastic testing (DAET) is based on the coupling of a low-frequency (LF) acoustic wave and high-frequency ultrasound (US) pulses (probing wave). It was developed to measure US viscoelastic and dissipative non-linearity in trabecular bone. It is well known that this complex biphasic medium contains microdamage, even when tissues are healthy. The purpose of the present study was to assess the sensitivity of DAET to monitor microdamage in human calcanei. Three protocols were therefore performed to investigate the regional heterogeneity of the calcaneus, the correlation between DAET measurements and microdamage revealed by histology, and DAET sensitivity to mechanically induced fatigue microdamage. The non-linear elastic parameter beta was computed for all these protocols. The study demonstrated the presence of high viscoelastic and dissipative non-linearity only in the region of the calcaneus close to the anterior talocalcaneal articulation (region of high bone density). Protocols 1 and 2 also showed that most unsorted calcanei did not naturally exhibit high non-linearity, which is correlated with a low level of microcracks. Nevertheless, when microdamage was actually present, high levels of US non-linearity were always found, with characteristic non-linear signatures such as hysteresis and tension/compression asymmetry. Finally, protocol 3 demonstrated the high sensitivity of DAET measurement to fatigue-induced microdamage.

Tibio-femoral joint constraints for bone pose estimation during movement using multi-body optimization

When using skin markers and stereophotogrammetry for movement analysis, bone pose estimation may be performed using multi-body optimization with the intent of reducing the effect of soft tissue artefacts. When the joint of interest is the knee, improvement of this approach requires defining subject-specific relevant kinematic constraints. The aim of this work was to provide these constraints in the form of plausible values for the distances between origin and insertion of the main ligaments (ligament lengths), during loaded healthy knee flexion, taking into account the indeterminacies associated with landmark identification during anatomical calibration. Ligament attachment sites were identified through virtual palpation on digital bone templates. Attachments sites were estimated for six knee specimens by matching the femur and tibia templates to low-dose stereoradiography images. Movement data were obtained using stereophotogrammetry and pin markers. Relevant ligament lengths for the anterior and posterior cruciate, lateral collateral, and deep and superficial bundles of the medial collateral ligaments (ACL, PCL, LCL, MCLdeep, MCLsup) were calculated. The effect of landmark identification variability was evaluated performing a Monte Carlo simulation on the coordinates of the origin-insertion centroids. The ACL and LCL lengths were found to decrease, and the MCLdeep length to increase significantly during flexion, while variations in PCL and MCLsup length was concealed by the experimental indeterminacy. An analytical model is given that provides subject-specific plausible ligament length variations as functions of the knee flexion angle and that can be incorporated in a multi-body optimization procedure.

[Heart failure and anaphylactic shock. A report of two cases]

Anaphylactic shock can sometimes take the appearance of heart failure, in relation to an acute coronary syndrome, even with normal coronary arteries, that we illustrate by two observations. We firstly report the case of an anaphylactic shock caused by succinylcholine, after anesthesia induction for inguinal hernia surgery in a 50-year-old man with cardiovascular risks, who presented with ventricular fibrillation followed by a cardiac arrest. An acute and severe anterior coronary syndrome was suspected and treated with thrombolysis. Then the electrocardiogram normalized, as well as the left ventricular function. No significant coronary stenosis was retrospectively revealed by coronarography, and a severe coronary vasospasm induced by the anaphylactic reaction was confirmed. We also describe the case of an anaphylactoid shock caused by cisatracurium infusion, that occurred at the beginning of an adnexectomy in a 55-year-old woman without any particular history. She presented with a cardiogenic shock after intravenous administration of epinephrine. The echocardiograpghic evaluation pointed out an aspect of stress-induced cardiomyopathy, and the coronarography showed normal coronary arteries. The left ventricular dysfunction completely normalized, strongly suggesting the diagnosis of Takotsubo-like syndrome after the anaphylactic shock and its treatment. Both of these cases point out the major interest of cardiologic and allergic evaluation in case of heart failure during general anesthesia. Coronary vasospasm and stress-induced cardiomyopathy are two pathologies that may be observed during anaphylactic shock, and their diagnosis should be considered after elimination of coronary thrombosis.

[Exertional hypertension and sport]

Defining the normal range of blood pressure during exertion is not easy. Each type of exercise induces increased blood pressure that responds to a particular curve, and adaptation modes differ according to age, gender, physical condition, basal blood pressure, etc. The best studied is blood pressure measured on the arm using a cycloergometre. Classical publications established blood pressure curves according to heart rate during exercise. It appears that the best scale of reference for power developed occurs in individuals who can provide a very high degree of effort and in particular, athletes who are in very good training. According to some authors, hypertension on exertion would entail a poor prognosis, even in the absence of resting hypertension. Nevertheless, there is presently no well established therapeutic recommendation concerning exertion hypertension. This approach could depend on resting blood pressure and on the existence of other risk factors. For an athlete, pursuing physical activity is most often encouraged, sometimes after treatment or adjustment of its level.

[A new case of pericardial thymic cyst]

The thymic cysts are benign tumours of the thymo-pharyngeal canal, usually located in the cervico-mediastinal region. The authors report the case of a large thymic cyst with an ectopic right paracardiac location compressing the right heart chambers. It was a chance finding on chest X-ray of an asymptomatic 21 year old man. Though suggestive of a pericardial cyst in view of its position, curative surgical ablation allowed confirmation of the diagnosis at anatomo-pathological examination.

[Retroclival hematoma in a patient taking oral anticoagulants]

Retroclival hematoma associated with anticoagulation. We report a case of retroclival hematoma associated with anticoagulant therapy in a 78-year-old-woman, who presented with an isolated left external ophthalmoplegia. The role of the anticoagulant therapy is discussed. There was a spontaneous neurological resolution.

[Chronic occlusion of the left coronary artery]

Chronic occlusion of the left main coronary artery is rare with less than 100 reported cases. the treatment is essentially surgical but medical management has been proposed. This case report illustrates the prognostic benefit of surgical management in view of the risk of secondary occlusion of the proximal right coronary artery.

Short report: isolation and partial characterization of a Puumala virus from a human case of nephropathia epidemica in France

Puumala (PUU) virus (Bunyaviridae: Hantavirus), the etiologic agent of nephropathia epidemica (NE), the mid form of hemorrhagic fever with renal syndrome, is enzootic in Europe and has been known to occur in France since 1983. We report the first isolation of PUU virus in France and western Europe from a case of NE acquired in France. The virus was isolated from a serum collected in the acute phase of the clinical course by successive blind passages in Vero E6 cells. Serologic typing using monoclonal antibodies confirmed the identity of the virus as PUU. The sequence of an 832-nucleotide fragment of the virus medium RNA segment obtained by the polymerase chain reaction (PCR) also classified it as a PUU virus. The sequence of this isolate from a human case in France is closely related to the sequence of a PUU virus obtained by the PCR from a German patient.