Ultra-high field magnetic resonance imaging of the quadriceps tendon enthesis in healthy subjects.

Purpose: Although enthesitis is a hallmark of several rheumatologic conditions, current imaging methods are still unable to characterize entheses changes because of the corresponding short transverse relaxation times (T2). A growing number of MR studies have used Ultra-High Field (UHF) MRI in order to assess low-T2 tissues e.g.

Specific brain activation patterns associated with two neuromuscular electrical stimulation protocols.

The influence of neuromuscular electrical stimulation (NMES) parameters on brain activation has been scarcely investigated. We aimed at comparing two frequently used NMES protocols - designed to vary in the extent of sensory input. Whole-brain functional magnetic resonance imaging was performed in sixteen healthy subjects during wide-pulse high-frequency (WPHF, 100 Hz-1 ms) and conventional (CONV, 25 Hz-0.

Correlative Analysis of Vertebral Trabecular Bone Microarchitecture and Mechanical Properties: A Combined Ultra-high Field (7 Tesla) MRI and Biomechanical Investigation.

Study Design: High-resolution imaging and biomechanical investigation of ex-vivo vertebrae.

Objective: The aim of this study was to assess bone microarchitecture of cadaveric vertebrae using ultra-high field (UHF) 7 Tesla magnetic resonance imaging (MRI) and to determine whether the corresponding microarchitecture parameters were related to bone mineral density (BMD) and bone strength assessed by dual-energy x-ray absorptiometry (DXA) and mechanical compression tests.

Summary Of Background Data: Limitations of DXA for the assessment of bone fragility and osteoporosis have been recognized and criteria of microarchitecture alteration have been included in the definition of osteoporosis.

The Etiology of Muscle Fatigue Differs between Two Electrical Stimulation Protocols.

Purpose: This study aimed at investigating the mechanisms involved in the force reduction induced by two electrical stimulation (ES) protocols that were designed to activate motor units differently.

Methods: The triceps surae of 11 healthy subjects (8 men; age, ~28 yr) was activated using ES applied over the tibial nerve. Two ES protocols (conventional [CONV]: 20 Hz, 0.

Volume measurements of individual muscles in human quadriceps femoris using atlas-based segmentation approaches.

Objectives: Atlas-based segmentation is a powerful method for automatic structural segmentation of several sub-structures in many organs. However, such an approach has been very scarcely used in the context of muscle segmentation, and so far no study has assessed such a method for the automatic delineation of individual muscles of the quadriceps femoris (QF). In the present study, we have evaluated a fully automated multi-atlas method and a semi-automated single-atlas method for the segmentation and volume quantification of the four muscles of the QF and for the QF as a whole.

Localization and quantification of intramuscular damage using statistical parametric mapping and skeletal muscle parcellation.

In the present study, we proposed an original and robust methodology which combines the spatial normalization of skeletal muscle images, the statistical parametric mapping (SPM) analysis and the use of a specific parcellation in order to accurately localize and quantify the extent of skeletal muscle damage within the four heads of the quadriceps femoris. T2 maps of thigh muscles were characterized before, two (D2) and four (D4) days after 40 maximal isometric electrically-evoked contractions in 25 healthy young males. On the basis of SPM analysis of coregistrated T2 maps, the alterations were similarly detected at D2 and D4 in the superficial and distal regions of the vastus medialis (VM) whereas the proportion of altered muscle was higher in deep muscle regions of the vastus lateralis at D4 (deep: 35 ± 25%, superficial: 23 ± 15%) as compared to D2 (deep: 18 ± 13%, superficial: 17 ± 13%).

Responders to Wide-Pulse, High-Frequency Neuromuscular Electrical Stimulation Show Reduced Metabolic Demand: A 31P-MRS Study in Humans.

Conventional (CONV) neuromuscular electrical stimulation (NMES) (i.e., short pulse duration, low frequencies) induces a higher energetic response as compared to voluntary contractions (VOL).

Standardized quantitative measurements of wrist cartilage in healthy humans using 3T magnetic resonance imaging.

Aim: To quantify the wrist cartilage cross-sectional area in humans from a 3D magnetic resonance imaging (MRI) dataset and to assess the corresponding reproducibility.

Methods: The study was conducted in 14 healthy volunteers (6 females and 8 males) between 30 and 58 years old and devoid of articular pain. Subjects were asked to lie down in the supine position with the right hand positioned above the pelvic region on top of a home-built rigid platform attached to the scanner bed.

Antinuclear Antibodies in Patients with Psoriatic Arthritis Treated or Not with Biologics.

Background: With the emergence of biotherapies, accurate diagnosis in early arthritis is needed. At this time, there is no biological marker of psoriatic arthritis.

Objective: To test whether antinuclear antibodies (ANA) can be used as a diagnostic tool in psoriatic arthritis (PsA), we evaluated the prevalence of ANA in biologic-naïve PsA patients and in healthy blood donors.

Effects of branched-chain amino acids supplementation on both plasma amino acids concentration and muscle energetics changes resulting from muscle damage: A randomized placebo controlled trial.

Background & Aims: Branched-chain amino acids promote muscle-protein synthesis, reduce protein oxidation and have positive effects on mitochondrial biogenesis and reactive oxygen species scavenging. The purpose of the study was to determine the potential benefits of branched-chain amino acids supplementation on changes in force capacities, plasma amino acids concentration and muscle metabolic alterations after exercise-induced muscle damage.

Methods: (31)P magnetic resonance spectroscopy and biochemical analyses were used to follow the changes after such damage.

Extra Forces induced by wide-pulse, high-frequency electrical stimulation: Occurrence, magnitude, variability and underlying mechanisms.

Objective: In contrast to conventional (CONV) neuromuscular electrical stimulation (NMES), the use of "wide-pulse, high-frequencies" (WPHF) can generate higher forces than expected by the direct activation of motor axons alone. We aimed at investigating the occurrence, magnitude, variability and underlying neuromuscular mechanisms of these "Extra Forces" (EF).

Methods: Electrically-evoked isometric plantar flexion force was recorded in 42 healthy subjects.

Impaired mitochondrial function and reduced energy cost as a result of muscle damage.

Purpose: Although it has been largely acknowledged that isometric neuromuscular electrostimulation (NMES) exercise induces larger muscle damage than voluntary contractions, the corresponding effects on muscle energetics remain to be determined. Voluntary exercise-induced muscle damage (EIMD) has been reported to have minor slight effects on muscle metabolic response to subsequent dynamic exercise, but the magnitude of muscle energetics alterations for NMES EIMD has never been documented.

Methods: ³¹P magnetic resonance spectroscopy measurements were performed in 13 young healthy males during a standardized rest-exercise-recovery protocol before (D0) and 2 d (D2) and 4 d (D4) after NMES EIMD on knee extensor muscles.

Time course of central and peripheral alterations after isometric neuromuscular electrical stimulation-induced muscle damage.

Isometric contractions induced by neuromuscular electrostimulation (NMES) have been shown to result in a prolonged force decrease but the time course of the potential central and peripheral factors have never been investigated. This study examined the specific time course of central and peripheral factors after isometric NMES-induced muscle damage. Twenty-five young healthy men were subjected to an NMES exercise consisting of 40 contractions for both legs.

Localized metabolic and t2 changes induced by voluntary and evoked contractions.

Purpose: This study compared the metabolic and activation changes induced by electrically evoked (neuromuscular electrical stimulation (NMES)) and voluntary (VOL) contractions performed at the same submaximal intensity using P chemical shift imaging (CSI) and T2 mapping investigations.

Methods: Fifteen healthy subjects were asked to perform both NMES and VOL protocols with the knee extensors (i.e.

Heterogeneity of muscle damage induced by electrostimulation: a multimodal MRI study.

Purpose: Neuromuscular electrostimulation (NMES) leads to a spatially fixed, synchronous, and superficial motor unit recruitment, which could induce muscle damage. Therefore, the extent of muscle damage and its spatial occurrence were expected to be heterogeneous across and along the quadriceps femoris (QF) muscles. The aim of the present study was to characterize muscle spatial heterogeneity in QF damage after a single bout of isometric NMES using multimodal magnetic resonance imaging (MRI).

Whole-Body (18) FDG-PET in an Arthritis Paraneoplastic Syndrome Revealed an Underlying Hematological Neoplasm.

We showed the first image of (18)FDG-PET, which leads to a diagnosis of lymphoma in an atypical polyarthritis. About 4% of patients with lymphoma or leukemia suffered from rheumatologic paraneoplastic symptoms like arthralgia and about 10% of the patients with rheumatologic or neurologic clinical symptoms develop a solid cancer or hematological neoplasm. (18)FDG-PET is an interesting exam to identify an underlying malignancy when a paraneoplastic syndrome is suspected; it can detect the primitive lesion and/or the metastasis lesions.

Safety of TNF-blocking agents in rheumatic patients with serology suggesting past hepatitis B state: results from a cohort of 21 patients.

Introduction: Reactivation of hepatitis B virus (HBV) infection in patients with past infection has been described in 5% to 10% of individuals undergoing immunosuppressive therapies. No data are available to date on the outcome of patients treated by tumour necrosis factor-alpha (TNFalpha) inhibitors for chronic arthritis with a serological pattern of past HBV infection. The aim of our study was to monitor HBV markers in HBV surface antigen (HBsAg)-negative/anti-HBcAb-positive patients treated with a TNFalpha inhibitor for inflammatory arthritides.

Influence of -308 A/G polymorphism in the tumor necrosis factor alpha gene on etanercept treatment in rheumatoid arthritis.

Objective: To determine whether the -308 A/G tumor necrosis factor alpha (TNFalpha) gene polymorphism can predict the outcome of etanercept therapy in 86 patients with rheumatoid arthritis (RA), as already observed in patients treated with infliximab.

Methods: Eighty-six RA patients treated with etanercept were genotyped for -308 A/G TNFalpha gene polymorphism by polymerase chain reaction and melting curve analysis, using specific gene primers and probes. Patients were subdivided into group A (G/A genotype) and group G (G/G genotype).

Calcaneal osteomyelitis due to fistulization of an ulcerated rheumatoid nodule.

Unlabelled: Calcaneal osteomyelitis is uncommon and difficult to treat. Cases due to fistulization of an infected rheumatoid nodule are exceedingly rare.

Patient: A 65-year-old patient with nodular rheumatoid arthritis (RA) experienced osteomyelitis of the left calcaneus due to inoculation from a fistula draining an ulcerated rheumatoid nodule.

Pathophysiology and clinical presentations of rhabdomyolysis.

Rhabdomyolysis has sparked new interest in recent years. The causes of rhabdomyolysis include drugs and other toxic agents, infections, physical exertion, crush injury, and muscle diseases (dystrophinopathies and metabolic myopathies). Prompt identification of the pathophysiological mechanism is the key to rapid control of the acute episode and to prevention of recurrences.