FDG uptake in giant cell tumor of the tendon sheath in a patient restaged for gastrointestinal stroma tumor (GIST)

A 70-year-old man known for recurrent abdominal gastrointestinal stroma tumor presented with a suspicious peritoneal mass demonstrated by an abdominal CT scan. Whole-body PET showed focal FDG uptake in the right hip, whereas the peritoneal mass was FDG negative. Histologic work-up of the PET positive lesion surprisingly revealed a giant cell tumor of the tendon sheath. The benignity of the peritoneal mass was confirmed by its disappearance in repeated CT scans. In general, focally increased FDG uptake should be subject to further investigations, especially in localizations that are not consistent with typical metastatic pathways of the former primary tumor.

Expression of atrophy mRNA relates to tendon tear size in supraspinatus muscle

Skeletal muscle atrophy and fatty infiltration develop after tendon tearing. The extent of atrophy serves as one prognostic factor for the outcome of surgical repair of rotator cuff tendon tears. We asked whether mRNA of genes involved in regulation of degradative processes leading to muscle atrophy, ie, FOXOs, MSTN, calpains, cathepsins, and transcripts of the ubiquitin-proteasome pathway, are overexpressed in the supraspinatus muscle in patients with and without rotator cuff tears. We evaluated biopsy specimens collected during surgery of 53 consecutive patients with different sizes of rotator cuff tendon tears and six without tears. The levels of corresponding gene transcripts in total RNA extracts were assessed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Supraspinatus muscle atrophy was assessed by MRI. The area of muscle tissue (or atrophy), decreased (increased) with increasing tendon tear size. The transcripts of CAPN1, UBE2B, and UBE3A were upregulated more than twofold in massive rotator cuff tears as opposed to smaller tears or patients without tears. These atrophy gene products may be involved in cellular processes that impair functional recovery of affected muscles after surgical rotator cuff repair. However, the damaging effects of gene products in their respective proteolytic processes on muscle structures and proteins remains to be investigated.

Adipogenic and myogenic gene expression in rotator cuff muscle of the sheep after tendon tear

Chronic rotator cuff tendon tears lead to fatty infiltration and muscle atrophy with impaired physiological functions of the affected muscles. However, the cellular and molecular mechanisms of corresponding pathophysiological processes remain unknown. The purpose of this study was to characterize the expression pattern of adipogenic (PPARgamma, C/EBPbeta) and myogenic (myostatin, myogenin, Myf-5) transcription factors in infraspinatus muscle of sheep after tenotomy, implantation of a tension device, refixation of the tendon, and rehabilitation, reflecting a model of chronic rotator cuff tears. In contrast to human patients, the presented sheep model allows a temporal evaluation of the expression of a given marker in the same individual over time. Semiquantitative RT/PCR analysis of PPARgammaã, myostatin, myogenin, Myf-5, and C/EBPbeta transcript levels was carried out with sheep muscle biopsy-derived total RNA. We found a significantly increased expression of Myf-5 and PPARgamma after tenotomy and a significant change for Myf-5 and C/EBPbeta after continuous traction and refixation. This experimental sheep model allows the molecular analysis of pathomechanisms of muscular changes after rotator cuff tear. The results point to a crucial role of the transcription factors PPARgamma, C/EBPbeta, and Myf-5 in impairment and regeneration of rotator cuff muscles after tendon tears in sheep.

Up-regulation of the peroxiredoxin-6 related metabolism of reactive oxygen species in skeletal muscle of mice lacking neuronal nitric oxide synthase

Although neuronal nitric oxide synthase (nNOS) plays a substantial role in skeletal muscle physiology, nNOS-knockout mice manifest an only mild phenotypic malfunction in this tissue. To identify proteins that might be involved in adaptive responses in skeletal muscle of knockout mice lacking nNOS, 2D-PAGE with silver-staining and subsequent tandem mass spectrometry (LC-MS/MS) was performed using extracts of extensor digitorum longus muscle (EDL) derived from nNOS-knockout mice in comparison to C57Bl/6 control mice. Six proteins were significantly (P < or = 0.05) more highly expressed in EDL of nNOS-knockout mice than in that of C57 control mice, all of which are involved in the metabolism of reactive oxygen species (ROS). These included prohibitin (2.0-fold increase), peroxiredoxin-3 (1.9-fold increase), Cu(2+)/Zn(2+)-dependent superoxide dismutase (SOD; 1.9-fold increase), heat shock protein beta-1 (HSP25; 1.7-fold increase) and nucleoside diphosphate kinase B (2.6-fold increase). A significantly higher expression (4.1-fold increase) and a pI shift from 6.5 to 5.9 of peroxiredoxin-6 in the EDL of nNOS-knockout mice were confirmed by quantitative immunoblotting. The concentrations of the mRNA encoding five of these proteins (the exception being prohibitin) were likewise significantly (P < or = 0.05) higher in the EDL of nNOS-knockout mice. A higher intrinsic hydrogen peroxidase activity (P < or = 0.05) was demonstrated in EDL of nNOS-knockout mice than C57 control mice, which was related to the presence of peroxiredoxin-6. The treatment of mice with the chemical NOS inhibitor L-NAME for 3 days induced a significant 3.4-fold up-regulation of peroxiredoxin-6 in the EDL of C57 control mice (P < or = 0.05), but did not alter its expression in EDL of nNOS-knockout mice. ESR spectrometry demonstrated the levels of superoxide to be 2.5-times higher (P < or = 0.05) in EDL of nNOS-knockout mice than in C57 control mice while an in vitro assay based on the emission of 2,7-dichlorofluorescein fluorescence disclosed the concentration of ROS to be similar in both strains of mice. We suggest that the up-regulation of proteins that are implicated in the metabolism of ROS, particularly of peroxiredoxin-6, within skeletal muscles of nNOS-knockout mice functionally compensates for the absence of nNOS in scavenging of superoxide.

Tenomodulin is necessary for tenocyte proliferation and tendon maturation

Tenomodulin (Tnmd) is a member of a new family of type II transmembrane glycoproteins. It is predominantly expressed in tendons, ligaments, and eyes, whereas the only other family member, chondromodulin I (ChM-I), is highly expressed in cartilage and at lower levels in the eye and thymus. The C-terminal extracellular domains of both proteins were shown to modulate endothelial-cell proliferation and tube formation in vitro and in vivo. We analyzed Tnmd function in vivo and provide evidence that Tnmd is processed in vivo and that the proteolytically cleaved C-terminal domain can be found in tendon extracts. Loss of Tnmd expression in gene targeted mice abated tenocyte proliferation and led to a reduced tenocyte density. The deposited amounts of extracellular matrix proteins, including collagen types I, II, III, and VI and decorin, lumican, aggrecan, and matrilin-2, were not affected, but the calibers of collagen fibrils varied significantly and exhibited increased maximal diameters. Tnmd-deficient mice did not have changes in tendon vessel density, and mice lacking both Tnmd and ChM-I had normal retinal vascularization and neovascularization after oxygen-induced retinopathy. These results suggest that Tnmd is a regulator of tenocyte proliferation and is involved in collagen fibril maturation but do not confirm an in vivo involvement of Tnmd in angiogenesis.

Left parietal activation related to planning, executing and suppressing praxis hand movements

OBJECTIVE: We sought to investigate the activity of bilateral parietal and premotor areas during a Go/No Go paradigm involving praxis movements of the dominant hand. METHODS: A sentence was presented which instructed subjects on what movement to make (S1; for example, "Show me how to use a hammer."). After an 8-s delay, "Go" or "No Go" (S2) was presented. If Go, they were instructed to make the movement described in the S1 instruction sentence as quickly as possible, and continuously until the "Rest" cue was presented 3 s later. If No Go, subjects were to simply relax until the next instruction sentence. Event-related potentials (ERP) and event-related desynchronization (ERD) in the beta band (18-22 Hz) were evaluated for three time bins: after S1, after S2, and from -2.5 to -1.5 s before the S2 period. RESULTS: Bilateral premotor ERP was greater than bilateral parietal ERP after the S2 Go compared with the No Go. Additionally, left premotor ERP was greater than that from the right premotor area. There was predominant left parietal ERD immediately after S1 for both Go and No Go, which was sustained for the duration of the interval between S1 and S2. For both S2 stimuli, predominant left parietal ERD was again seen when compared to that from the left premotor or right parietal area. However, the left parietal ERD was greater for Go than No Go. CONCLUSION: The results suggest a dominant role in the left parietal cortex for planning, executing, and suppressing praxis movements. The ERP and ERD show different patterns of activation and may reflect distinct neural movement-related activities. SIGNIFICANCE: The data can guide further studies to determine the neurophysiological changes occurring in apraxia patients and help explain the unique error profiles seen in patients with left parietal damage.

A practical posture for hand grip dynamometry in the clinical setting

The optimal testing position for hand grip strength, which is a useful functional measure of nutritional status, is open to debate. We therefore examined the systematic difference between different postures in order to establish a methodology that is clinically relevant, easy to perform and reproducible.

Mesenteric lymphangitis and sepsis due to RTX toxin-producing Actinobacillus spp in 2 foals with hypothyroidism-dysmaturity syndrome

Actinobacillus suis-like organisms (ASLOs) have been isolated from the genital, respiratory, and digestive tracts of healthy adult horses, horses with respiratory disease, and septic foals. Two foals with congenital hypothyroidism-dysmaturity syndrome from separate farms developed ASLO infection. At necropsy, both had contracted carpal flexor tendons, thyroid hyperplasia, and thrombotic and necrotizing mesenteric lymphangitis and lymphadenitis; one foal also had mandibular prognathism. Numerous ASLOs were isolated from tissues from both foals, including intestine. Biochemical testing and mass spectrometric analysis of the two Actinobacillus isolates did not allow unequivocal identification. Comparative genetic analysis was done on these and similar isolates, including phylogeny based on 16S rRNA, rpoB and recN genes, as well as RTX (repeat in toxin) toxin typing of apxIA-apxIVA and aqxA genes. One isolate was identified as Actinobacillus suis sensu stricto, based on the presence of apxIA and apxIIA but not aqxA, whereas the other isolate had aqxA but neither apxIA nor apxIIA, consistent with A equuli ssp haemolyticus. Based on genotypic analysis of the isolates included for comparison, 3 of 3 equine ASLOs and 2 of 5 A equuli isolates were reclassified as A equuli subsp haemolyticus, emphasizing the importance of toxin genotyping in accurate classification of actinobacilli.

Tenocytes of chronic rotator cuff tendon tears can be stimulated by platelet-released growth factors

BACKGROUND Bone-to-tendon healing after rotator cuff repairs is mainly impaired by poor tissue quality. The tenocytes of chronic rotator cuff tendon tears are not able to synthesize normal fibrocartilaginous extracellular matrix (ECM). We hypothesized that in the presence of platelet-released growth factors (PRGF), tenocytes from chronically retracted rotator cuff tendons proliferate and synthesize the appropriate ECM proteins. MATERIALS AND METHODS Tenocytes from 8 patients with chronic rotator cuff tears were cultured for 4 weeks in 2 different media: standard medium (Iscove's Modified Dulbecco's Media + 10% fetal calf serum + 1% nonessential amino acids + 0.5 μg/mL ascorbic acid) and media with an additional 10% PRGF. Cell proliferation was assessed at 7, 14, 21, and 28 days. Messenger (m)RNA levels of collagens I, II, and X, decorin, biglycan, and aggrecan were analyzed using real time reverse-transcription polymerase chain reaction. Immunocytochemistry was also performed. RESULTS The proliferation rate of tenocytes was significantly higher at all time points when cultured with PRGF. At 21 days, the mRNA levels for collagens I, II, and X, decorin, aggrecan, and biglycan were significantly higher in the PRGF group. The mRNA data were confirmed at protein level by immunocytochemistry. CONCLUSIONS PRGFs enhance tenocyte proliferation in vitro and promote synthesis of ECM to levels similar to those found with insertion of the normal human rotator cuffs. CLINICAL RELEVANCE Biologic augmentation of repaired rotator cuffs with PRGF may enhance the properties of the repair tissue. However, further studies are needed to determine if application of PRGF remains safe and effective in long-term clinical studies. LEVEL OF EVIDENCE Basic Science Study, Cell Biology.

Transition from nerve stimulator to sonographically guided axillary brachial plexus anesthesia in hand surgery: block quality and patient satisfaction during the transition period

OBJECTIVES Sonographic guidance for peripheral nerve anesthesia has proven increasingly successful in clinical practice; however, fears that a change to sonographically guided regional anesthesia may impair the block quality and operating room work flow persist in certain units. In this retrospective cohort study, block quality and patient satisfaction during the transition period from nerve stimulator to sonographic guidance for axillary brachial plexus anesthesia in a tertiary referral center were investigated. METHODS Anesthesia records of all patients who had elective surgery of the wrist or hand during the transition time (September 1, 2006-August 25, 2007) were reviewed for block success, placement time, anesthesiologist training level, local anesthetic volume, and requirement of additional analgesics. Postoperative records were reviewed, and patient satisfaction was assessed by telephone interviews in matched subgroups. RESULTS Of 415 blocks, 341 were sonographically guided, and 74 were nerve stimulator guided. Sonographically guided blocks were mostly performed by novices, whereas nerve stimulator-guided blocks were performed by advanced users (72.3% versus 14%; P < .001). Block performance times and success rates were similar in both groups. In sonographically guided blocks, significantly less local anesthetics were applied compared to nerve stimulator-guided blocks (mean ± SD, 36.1 ± 7.1 versus 43.9 ± 6.1 mL; P< .001), and less opioids were required (fentanyl, 66.1 ± 30 versus 90 ± 62 μg; P< .001). Interviewed patients reported significantly less procedure-related discomfort, pain, and prolonged procedure time when block placement was sonographically guided (2% versus 20%; P = .002). CONCLUSIONS Transition from nerve stimulator to sonographic guidance for axillary brachial plexus blocks did not change block performance times or success rates. Patient satisfaction was improved even during the early institutional transition period.

Use of a hand-assisted laparoscopic surgical technique for closure of an extensive mesojejunal rent in a horse

CASE DESCRIPTION A 7-year-old 573-kg (1,261 -lb) Swiss Warmblood gelding was evaluated because of signs of acute abdominal pain. CLINICAL FINDINGS Physical examination revealed a markedly distended abdomen with subjectively reduced borborygmi in all abdominal quadrants. A large, gas-distended viscus was present at the pelvic brim preventing complete palpation of the abdomen per rectum. Ultrasonographic evaluation could not be safely performed in the initial evaluation because of severe signs of abdominal pain. TREATMENT AND OUTCOME Ventral midline celiotomy was performed, and right dorsal displacement of the ascending colon was corrected. Progressive signs of abdominal pain after surgery prompted repeat ventral midline celiotomy, and small intestinal incarceration in a large, radial mesojejunal rent was detected. The incarceration was reduced, but the defect was not fully accessible for repair via the celiotomy. Repair of the mesenteric defect was not attempted, and conservative management was planned after surgery; however, signs of colic returned. A standard laparoscopic approach was attempted from both flanks in the standing patient, but the small intestine could not be adequately mobilized for full evaluation of the rent. Hand-assisted laparoscopic surgery (HALS) allowed identification and reduction of jejunal incarceration and repair of the mesenteric rent. Although minor ventral midline incisional complications were encountered, the horse recovered fully. CLINICAL RELEVANCE HALS techniques should be considered for repair of mesenteric rents in horses. In the horse of this report, HALS facilitated identification, evaluation, and repair of a large radial mesenteric rent that was not accessible from a ventral median celiotomy.

Finite element based estimation of contact areas and pressures of the human scaphoid in various functional positions of the hand

The scaphoid is the most frequently fractured carpal bone. When investigating fixation stability, which may influence healing, knowledge of forces and moments acting on the scaphoid is essential. The aim of this study was to evaluate cartilage contact forces acting on the intact scaphoid in various functional wrist positions using finite element modeling. A novel methodology was utilized as an attempt to overcome some limitations of earlier studies, namely, relatively coarse imaging resolution to assess geometry, assumption of idealized cartilage thicknesses and neglected cartilage pre-stresses in the unloaded joint. Carpal bone positions and articular cartilage geometry were obtained independently by means of high resolution CT imaging and incorporated into finite element (FE) models of the human wrist in eight functional positions. Displacement driven FE analyses were used to resolve inter-penetration of cartilage layers, and provided contact areas, forces and pressure distribution for the scaphoid bone. The results were in the range reported by previous studies. Novel findings of this study were: (i) cartilage thickness was found to be heterogeneous for each bone and vary considerably between carpal bones; (ii) this heterogeneity largely influenced the FE results and (iii) the forces acting on the scaphoid in the unloaded wrist were found to be significant. As major limitations, accuracy of the method was found to be relatively low, and the results could not be compared to independent experiments. The obtained results will be used in a following study to evaluate existing and recently developed screws used to fix scaphoid fractures.

Restoring tactile awareness through the rubber hand illusion in cervical spinal cord injury

BACKGROUND Bodily sensations are an important component of corporeal awareness. Spinal cord injury can leave affected body parts insentient and unmoving, leading to specific disturbances in the mental representation of one's own body and the sense of self. OBJECTIVE Here, we explored how illusions induced by multisensory stimulation influence immediate sensory signals and tactile awareness in patients with spinal cord injuries. METHODS The rubber hand illusion paradigm was applied to 2 patients with chronic and complete spinal cord injury of the sixth cervical spine, with severe somatosensory impairments in 2 of 5 fingers. RESULTS Both patients experienced a strong illusion of ownership of the rubber hand during synchronous, but not asynchronous, stroking. They also, spontaneously reported basic tactile sensations in their previously numb fingers. Tactile awareness from seeing the rubber hand was enhanced by progressively increasing the stimulation duration. CONCLUSIONS Multisensory illusions directly and specifically modulate the reemergence of sensory memories and enhance tactile sensation, despite (or as a result of) prior deafferentation. When sensory inputs are lost, and are later illusorily regained, the brain updates a coherent body image even several years after the body has become permanently unable to feel. This particular example of neural plasticity represents a significant opportunity to strengthen the sense of the self and the feelings of embodiment in patients with spinal cord injury.