Early Functional Treatment of Proximal Phalanx Fractures in Children: A Case Series Study.

OBJECTIVES: The objective of this study was to assess proper indications a nonsurgical treatment regime for pediatric fractures of the proximal phalanx based on principles of early functional treatment. METHODS: A case series (evidence level 4) of 30 pediatric patients with fractures of the proximal phalanx were treated nonsurgically using protective dynamic splinting techniques and fiberglass casting material. Assessments were performed clinically and by x-ray within 4 to 8 weeks of commencement of treatment. Outcome measures included Disabilities of the Arm, Shoulder, and Hand score questionnaire as well as fingertip palm distance (cm) and dynamic pain interval assessments. RESULTS: All fractures healed without any clinically apparent bony deformities. Disabilities of the Arm, Shoulder, and Hand scores were of 25.17 ± 5.29 (mean ± SD), which indicated good functional results usually within 2 weeks of removal of dynamic splints. Fingertip palm distance measurements at endpoints were of 0.17 ± 0.27 cm (mean ± SD), which indicated an almost free range of finger motion. Absence of pain perception under active finger motion (dynamic pain interval) was noted at 14.10 ± 6.79 days (mean ± SD). CONCLUSIONS: Well-established criteria for surgical treatment of phalangeal fractures exist. However, in our experience, a majority of pediatric fractures of the proximal phalanx can be safely treated nonsurgically with dynamic splinting along with shorter intervals of immobilization of the affected fingers and faster restoration of overall hand function compared to surgical treatment.

Vimentin fragments are potential markers of rheumatoid synovial fibroblasts.

OBJECTIVES: To study the protein expression differences between primary fibroblasts explanted from synovial membranes of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: Fibroblast cultures were obtained from 10 patients with RA and 5 patients with OA. After two-dimensional gel electrophoresis, proteins were excised and identified using peptide mass fingerprint. Expression of selected proteins was subsequently examined by immunoblot. Furthermore, we examined the cellular lysates for the presence of citrullinated proteins. RESULTS: The study was designed to compare expression changes of the common proteins detected in all studied fibroblast cultures (i.e. detected in all patients samples). We totally identified 191 shared proteins between RA and OA fibroblasts. A significant difference was defined as at least 2-fold upregulation or 0.6-fold downregulation of protein expression. The most obvious alteration observed in RA was the appearance of several vimentin fragments not present in OA. We did not detect citrullinated proteins in lysates from RA fibroblasts. This corroborates the current assumption that fibroblasts are not able to citrullinate proteins by themselves and that invading macrophages play a central role in this process. CONCLUSIONS: We demonstrated that fibroblasts from patients with RA, despite being grown under identical conditions, preserve a particular feature and generate vimentin fragments not present in fibroblasts from OA. Elevated levels of different vimentin fragments have been recently reported in several rheumatic conditions. Further studies are needed to elucidate the pathogenic mechanisms induced by vimentin fragments in RA.

Alternative erythropoietin-mediated signaling prevents secondary microvascular thrombosis and inflammation within cutaneous burns.

Alternate erythropoietin (EPO)-mediated signaling via the heteromeric receptor composed of the EPO receptor and the ß-common receptor (CD131) exerts the tissue-protective actions of EPO in various types of injuries. Herein we investigated the effects of the EPO derivative helix beta surface peptide (synonym: ARA290), which specifically triggers alternate EPO-mediated signaling, but does not bind the erythropoietic EPO receptor homodimer, on the progression of secondary tissue damage following cutaneous burns. For this purpose, a deep partial thickness cutaneous burn injury was applied on the back of mice, followed by systemic administration of vehicle or ARA290 at 1, 12, and 24 h postburn. With vehicle-only treatment, wounds exhibited secondary microvascular thrombosis within 24 h postburn, and subsequent necrosis of the surrounding tissue, thus converting to a full-thickness injury within 48 h. On the other hand, when ARA290 was systemically administered, patency of the microvasculature was maintained. Furthermore, ARA290 mitigated the innate inflammatory response, most notably tumor necrosis factor-alpha-mediated signaling. These findings correlated with long-term recovery of initially injured yet viable tissue components. In conclusion, ARA290 may be a promising therapeutic approach to prevent the conversion of partial- to full-thickness burn injuries. In a clinical setting, the decrease in burn depth and area would likely reduce the necessity for extensive surgical debridement as well as secondary wound closure by means of skin grafting. This use of ARA290 is consistent with its tissue-protective properties previously reported in other models of injury, such as myocardial infarction and hemorrhagic shock.

Resolvin D2 prevents secondary thrombosis and necrosis in a mouse burn wound model.

Deep partial thickness burns are subject to delayed necrosis of initially viable tissues surrounding the primary zone of thermally induced coagulation, which results in an expansion of the burn wound, both in area and depth, within 48 hours postburn. Neutrophil sequestration and activation leading to microvascular damage is thought to mediate this secondary tissue damage. Resolvins, a class of endogenous mediators derived from omega-3 polyunsaturated fatty acids, have been shown to regulate the resolution of inflammation. We hypothesized that exogenous resolvins could mitigate the deleterious impact of the inflammatory response in burn wounds. Using two different mouse burn injury models involving significant partial thickness injuries, we found that a systemically administered single dose of resolvin D2 (RvD2) as low as 25 pg/g bw given within an interval of up to 4 hours postburn effectively prevented thrombosis of the deep dermal vascular network and subsequent dermal necrosis. By preserving the microvascular network, RvD2 enhanced neutrophil access to the dermis, but prevented neutrophil-mediated damage through other anti-inflammatory actions, including inhibition of tumor necrosis factor-α, interleukin-1ß, and neutrophil platelet-endothelial cell adhesion molecule-1. In a clinical context, RvD2 may be therapeutically useful by reducing the need for surgical debridement and the area requiring skin grafting.

Fractional anisotropy correlates with auditory simple reaction time performance.

During the last two decades, modern imaging studies focused intensively on the broad field of reaction time paradigms and significantly enhanced the understanding of behavioral performance. However, interindividual variations of simple reaction time (SRT) have been barely investigated. In this study, we intended to identify neural correlates of interindividual variation in auditory SRT (aSRT) employing the Poffenberger paradigm with auditory stimuli, in order to investigate neural processing speed performance. We conducted a whole-head voxel based morphometry analysis of fractional anisotropy (FA) in 19 healthy, right handed subjects. Simple regression analysis between FA and interindividual aSRT measures was performed for each voxel. Significant positive correlation (R(2): 0.44/0.78 min/max) for FA vs. individual mean aSRT was found in the right central cerebellum dorso-cranial of the dentate nucleus. A significant correlation (R(2): 0.453/0.633 min/max) was also detected between FA and the hand performance index, which characterizes the intraindividual RT difference between left and right hand, within the precentral portion of the pyramidal tract in the left hemisphere. Fast right handed response correlated with high local FA values located within neural structures participating in right hand control. Against the background of only right handed participants in our study, the hypothesis of local myelination as one basic condition influencing reaction time performance is strongly supported. The presented results identify brain areas involved in the processing speed of the aSRT tasks. We propose that the presented findings are due to an influence of participants' right hand preference on both FA and aSRT measures.

A Novel Resolvin-Based Strategy for Limiting Acetaminophen Hepatotoxicity.

OBJECTIVES: Acetaminophen (APAP)-induced hepatotoxicity is a major cause of morbidity and mortality. The current pharmacologic treatment for APAP hepatotoxicity, N-acetyl cysteine (NAC), targets the initial metabolite-driven injury but does not directly affect the host inflammatory response. Because of this, NAC is less effective if given at later stages in the disease course. Resolvins, a novel group of lipid mediators shown to attenuate host inflammation, may be a therapeutic intervention for APAP hepatotoxicity. METHODS: The temporal patterns of liver injury and neutrophil activation were investigated in a murine model of APAP hepatotoxicity. In addition, the effect of neutrophil depletion and resolvin administration on the severity of liver injury induced by APAP was studied. In vitro studies to investigate the mechanism of resolvin effect on hepatocyte injury and neutrophil adhesion were performed. RESULTS: We demonstrate that hepatic neutrophil activation occurs secondary to the initial liver injury induced directly by APAP. We also show that neutrophil depletion attenuates APAP-induced liver injury, and administration of resolvins hours after APAP challenge not only attenuates liver injury, but also extends the therapeutic window eightfold compared to NAC. Mechanistic in vitro analysis highlights resolvins' ability to inhibit neutrophil attachment to endothelial cells in the presence of the reactive metabolite of APAP. CONCLUSIONS: This study highlights the ability of resolvins to protect against APAP-induced liver injury and extend the therapeutic window compared to NAC. Although the mechanism for resolvin-mediated hepatoprotection is likely multifactorial, inhibition of neutrophil infiltration and activation appears to play an important role.

Cell-Enriched Lipoaspirate Arthroplasty: A Novel Approach to First Carpometacarpal Joint Arthritis.

We report a novel, minimal invasive technique for the treatment of symptomatic arthritis of the carpometacarpal (CMC) joint of the thumb, here termed Cell-Enriched Liposaspirate Arthroplasty (CELA). For CELA, autologous fat tissue was harvested using standard liposuction technique followed by an extra-corporal cellular enrichment step. Finally, 1 ml of cell-enriched lipoaspirate was injected into the CMC-joint. Following CELA, the treated patient became pain free within five weeks with a follow-up of 12 months. We conclude that CELA performed on selected cases of arthritis of finger joints such as the basal joint of the thumb has the potential to greatly reduce or delay the necessity for more invasive procedures which tend to improve symptoms of pain at the cost of grip strength and range-of-motion.

The Role of CHI3L1 (Chitinase-3-Like-1) in the Pathogenesis of Infections in Burns in a Mouse Model.

In severe burn injury the unique setting of a depleted, dysfunctional immune system along with a loss of barrier function commonly results in opportunistic infections that eventually proof fatal. Unfortunately, the dynamic sequence of bacterial contamination, colonization and eventually septic invasion with bacteria such as Pseudomonas species is still poorly understood although a limiting factor in clinical decision making. Increasing evidence supports the notion that inhibition of bacterial translocation into the wound site may be an effective alternative to prevent infection. In this context we investigated the role of the mammalian Chitinase-3-Like-1 (CHI3L1) non-enyzmatic protein predominately expressed on epithelial as well as innate immune cells as a potential bacterial-translocation-mediating factor. We show a strong trend that a modulation of chitinase expression is likely to be effective in reducing mortality rates in a mouse model of burn injury with superinfection with the opportunistic PA14 Pseudomonas strain, thus demonstrating possible clinical leverage.

Modulation of cellular stress response via the erythropoietin/CD131 heteroreceptor complex in mouse mesenchymal-derived cells.

Tissue-protective properties of erythropoietin (EPO) have let to the discovery of an alternative EPO signaling via an EPO-R/CD131 receptor complex which can now be specifically targeted through pharmaceutically designed short sequence peptides such as ARA290. However, little is still known about specific functions of alternative EPO signaling in defined cell populations. In this study, we investigated effects of signaling through EPO-R/CD131 complex on cellular stress responses and pro-inflammatory activation in different mesenchymal-derived phenotypes. We show that anti-apoptotic, anti-inflammatory effects of ARA290 and EPO coincide with the externalization of CD131 receptor component as an immediate response to cellular stress. In addition, alternative EPO signaling strongly modulated transcriptional, translational, or metabolic responses after stressor removal. Specifically, we saw that ARA290 was able to overcome a TNFα-mediated inhibition of transcription factor activation related to cell stress responses, most notably of serum response factor (SRF), heat shock transcription factor protein 1 (HSF1), and activator protein 1 (AP1). We conclude that alternative EPO signaling acts as a modulator of pro-inflammatory signaling pathways and likely plays a role in restoring tissue homeostasis. Key message: Erythropoietin (EPO) triggers an alternative pathway via heteroreceptor EPO/CD131. ARA290 peptide specifically binds EPO/CD131 but not the canonical EPO/EPO receptor. Oxidative stress and inflammation promote cell surface expression of CD131. ARA290 prevents tumor necrosis factor-mediated inhibition of stress-related genes. Alternative EPO signaling modulates inflammation and promotes tissue homeostasis.

Hepatic Injury in Nonalcoholic Steatohepatitis Contributes to Altered Intestinal Permeability.

BACKGROUND & AIMS: Emerging data suggest that changes in intestinal permeability and increased gut microbial translocation contribute to the inflammatory pathway involved in nonalcoholic steatohepatitis (NASH) development. Numerous studies have investigated the association between increased intestinal permeability and NASH. Our meta-analysis of this association investigates the underlying mechanism. METHODS: A meta-analysis was performed to compare the rates of increased intestinal permeability in patients with NASH and healthy controls. To further address the underlying mechanism of action, we studied changes in intestinal permeability in a diet-induced (methionine-and-choline-deficient; MCD) murine model of NASH. In vitro studies were also performed to investigate the effect of MCD culture medium at the cellular level on hepatocytes, Kupffer cells, and intestinal epithelial cells. RESULTS: Nonalcoholic fatty liver disease (NAFLD) patients, and in particular those with NASH, are more likely to have increased intestinal permeability compared with healthy controls. We correlate this clinical observation with in vivo data showing mice fed an MCD diet develop intestinal permeability changes after an initial phase of liver injury and tumor necrosis factor-α (TNFα) induction. In vitro studies reveal that MCD medium induces hepatic injury and TNFα production yet has no direct effect on intestinal epithelial cells. Although these data suggest a role for hepatic TNFα in altering intestinal permeability, we found that mice genetically resistant to TNFα-myosin light chain kinase (MLCK)-induced intestinal permeability changes fed an MCD diet still develop increased permeability and liver injury. CONCLUSIONS: Our clinical and experimental results strengthen the association between intestinal permeability increases and NASH and also suggest that an early phase of hepatic injury and inflammation contributes to altered intestinal permeability in a fashion independent of TNFα and MLCK.

Resolving cancer-stroma interfacial signalling and interventions with micropatterned tumour-stromal assays.

Tumour-stromal interactions are a determining factor in cancer progression. In vivo, the interaction interface is associated with spatially resolved distributions of cancer and stromal phenotypes. Here, we establish a micropatterned tumour-stromal assay (µTSA) with laser capture microdissection to control the location of co-cultured cells and analyse bulk and interfacial tumour-stromal signalling in driving cancer progression. µTSA reveals a spatial distribution of phenotypes in concordance with human oestrogen receptor-positive (ER+) breast cancer samples, and heterogeneous drug activity relative to the tumour-stroma interface. Specifically, an unknown mechanism of reversine is shown in targeting tumour-stromal interfacial interactions using ER+ MCF-7 breast cancer and bone marrow-derived stromal cells. Reversine suppresses MCF-7 tumour growth and bone metastasis in vivo by reducing tumour stromalization including collagen deposition and recruitment of activated stromal cells. This study advocates µTSA as a platform for studying tumour microenvironmental interactions and cancer field effects with applications in drug discovery and development.

Non-thermal, pulsed electric field cell ablation: A novel tool for regenerative medicine and scarless skin regeneration.

High voltage, short pulsed electric fields (PEF) is a non-thermal ablation method, in which defined PEF irreversibly destabilize cell membranes, while preserving other tissue components such as the extracellular matrix (ECM). In the present report, we show that PEF ablated rat skin retains its microvascular blood supply and ECM structure. Complete regeneration of epidermis, hair follicles, sebaceous glands, and the panniculus carnosusis observed two months after the ablation. Our results clearly indicate that non-thermal PEF has the potential to be a powerful and novel tool for scarless tissue regeneration.

Highly upregulated Lhx2 in the Foxn1-/- nude mouse phenotype reflects a dysregulated and expanded epidermal stem cell niche.

Hair cycling is a prime example of stem cell dependent tissue regeneration and replenishment, and its regulatory mechanisms remain poorly understood. In the present study, we evaluated the effect of a blockage in terminal keratinocytic lineage differentiation in the Foxn1(-/-) nude phenotype on the epithelial progeny. Most notably we found a constitutive upregulation of LIM homeobox protein 2 (Lhx2), a marker gene of epithelial stem cellness indispensible for hair cycle progression. However, histological evidence along with an erratic, acyclic rise of otherwise suppressed CyclinD1 levels along with several key markers of keratinocyte lineage differentiation indicate a frustrated expansion of epithelial stem cell niches in skin. In addition, CD49f/CD34/CD200-based profiling demonstrated highly significant shifts in subpopulations of epithelial progeny. Intriguingly this appeared to include the expansion of Oct4+ stem cells in dermal fractions of skin isolates in the Foxn1 knock-out opposed to wild type. Overall our findings indicate that the Foxn1(-/-) phenotype has a strong impact on epithelial progeny and thus offers a promising model to study maintenance and regulation of stem cell niches within skin not feasible in other in vitro or in vivo models.

Endothelial peroxisomal dysfunction and impaired pexophagy promotes oxidative damage in lipopolysaccharide-induced acute kidney injury.

AIMS: We examined that (a) how the endotoxic stress affects peroxisomal function and autophagic degradation of peroxisomes-pexophagy, (b) how a superimposed dysfunction of lysosomes and pexophagy modifies responses to lipopolysaccharide (LPS), and (c) the mechanisms of peroxisomal contribution to renal injury. To accomplish this, we used lysosome-defective Lyst-mice in vivo and primary endothelial cells in vitro, and compared the responses with wild-type (WT) littermates. RESULTS: LPS induced pexophagic degradation, followed by proliferation of peroxisomes in WT mice, which was abolished in Lyst-mice. Lyst-mice exhibited impaired activation of catalase, which together with preserved hydrogen peroxide-generating ß-oxidation resulted in redox disequilibrium. LPS treatment induced a heightened inflammatory response, increased oxidative damage, and aggravated renal injury in Lyst-mice. Similarly, as in vivo, LPS-activated lysosomal (LYS) pexophagy and transiently repressed peroxisomes in vitro, supported by reduced peroxisomal density in the vicinity of lysosomes. Peroxisomal dynamics was also abolished in lysosome-defective cells, which accumulated peroxisomes with compromised functions and intraorganellar redox imbalance. INNOVATION: We demonstrated that pexophagy is a default response to endotoxic injury. However, when LYS dysfunction (a frequent companion of chronic diseases) is superimposed, recycling and functioning of peroxisomes are impaired, and an imbalance between hydrogen peroxide-generating ß-oxidation and hydrogen peroxide-detoxifying catalase ensues, which ultimately results in peroxisomal burnout. CONCLUSION: Our data strongly suggest that pexophagy, a cellular mechanism per se, is essential in functional maintenance of peroxisomes during LPS exposure. Inhibition of pexophagy results in accumulation of impaired peroxisomes, redox disequilibrium, and aggravated renal damage.

Gap junction inhibition prevents drug-induced liver toxicity and fulminant hepatic failure.

Drug-induced liver injury (DILI) limits the development and application of many therapeutic compounds and presents major challenges to the pharmaceutical industry and clinical medicine. Acetaminophen-containing compounds are among the most frequently prescribed drugs and are also the most common cause of DILI. Here we describe a pharmacological strategy that targets gap junction communication to prevent amplification of fulminant hepatic failure and acetaminophen-induced hepatotoxicity. We demonstrate that connexin 32 (Cx32), a key hepatic gap junction protein, is an essential mediator of DILI by showing that mice deficient in Cx32 are protected against liver damage, acute inflammation and death caused by liver-toxic drugs. We identify a small-molecule inhibitor of Cx32 that protects against liver failure and death in wild-type mice when co-administered with known hepatotoxic drugs. These findings indicate that gap junction inhibition could provide a pharmaceutical strategy to limit DILI and improve drug safety.

Long-term effects of saw osteotomy versus random fracturing on bone healing and remodeling in a sheep tibia model.

This article is about the evaluation of possible differences in biomechanical or histomorphological properties of bone healing between saw osteotomy and random fracturing after 6 months. A standardized, 30 degrees oblique monocortical saw osteotomy of sheep tibia was carried out, followed by manual fracture completion of the opposed cortical bone. Fixation was performed by bridge plating (4.5 mm, LCDCP, broad). X-rays were taken immediately after surgery and at the end of the study. Polychrome fluorescent staining was performed according to a standardized protocol in the 2nd, 4th 6th, 10th, 14th, 18th, 22th and 26th week. Ten sheep were comprehensively evaluated. Data for stiffness and histomorphology are reported. The average bending stiffness of the operated bone was higher (1.7 (SD 0.3) with plate (MP) vs. 1.5 without plate) than for the intact bone (1.4 (SD 0.2), though no significant differences in bending stiffness were observed (P>0.05). Fluorescence staining revealed small numbers of blood vessels and less fragment resorption and remodeling in the osteotomy gap. Bone healing after saw osteotomy shows a very close resemblance to 'normal' fracture healing. However, vascular density, fragment resorption, fragment remodeling, and callus remodeling are reduced at the osteotomy.

Clinical results of absorbable plates for displaced metacarpal fractures.

PURPOSE: To present the clinical results of a study of unstable metacarpal fractures treated with absorbable plates. METHODS: Between July 2004 and June 2006, 12 patients (14 fractures) who presented with displaced, unstable, metacarpal fractures had open reduction and internal fixation. The overall clinical follow-up results and radiographic controls at 6, 12, and 26 weeks after surgery are reported. The clinical outcome was assessed by the Disabilities of the Arm, Shoulder, and Hand score and the visual analogue pain scale. RESULTS: The involved fingers showed an average final total active motion of 234 degrees (range, 220 degrees-265 degrees). No deformity of rotation>5 degrees was observed in any patient in the clinical follow-up evaluation. One patient had a loss of reduction with a palmar angle of the metacarpal axis of 20 degrees in the sagittal plane. A second patient with secondary loss of reduction required surgical revision, at which time internal fixation was performed by using a titanium plate. Complications included keloid formation and prolonged soft-tissue swelling for more than 6 weeks in 3 patients. No wound margin necrosis, infection, pseudarthrosis, sinus formation, or osteolysis was observed. Bone consolidation was achieved reliably within 6 weeks both clinically and radiologically. The Disabilities of the Arm, Shoulder, and Hand score results 6 weeks after surgery were an average of 30 points compared with 13 after 12 weeks and 3 points after 26 weeks. The visual pain scale showed mean values of 18 after 6 weeks, 2 after 12 weeks, and 0.2 after 26 weeks. CONCLUSIONS: Absorbable plates are suitable for use in hand surgery and allow early range of motion in combination with an additional orthosis of the hand (as described) for 3 weeks. In the early and medium-term postoperative course, no osteolysis or sterile sinus formation was observed. Metal plates are still the gold standard; however, surgical implants made of amorphous copolymer of L-lactide and glycolic acid in combination with an orthosis constitute a useful and reliable means of metacarpal fracture treatment. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.