Transcriptional and posttranscriptional regulators of biglycan in cardiac fibroblasts.
Basic Res Cardiol. 2009 Aug 23; Tiede K, Melchior-Becker A, Fischer JWBiglycan, a small leucine-rich proteoglycan, is essential for scar formation and preservation of hemodynamic function after myocardial infarction, as shown in biglycan-knockout mice. Because of this important role in cardiac pathophysiology, we aimed to identify regulators of biglycan expression and posttranslational modifications in cardiac fibroblasts. Cardiac fibroblasts were isolated from neonatal Wistar-Kyoto rats and used in the first passage. Expression of biglycan was analyzed after metabolic labeling with [(35)S]-sulfate by SDS-polyacrylamide gel electrophoresis and molecular sieve chromatography; mRNA expression was examined by Northern analysis and real-time RT-PCR. Serum, thrombin, transforming growth factor beta1 (TGFbeta 1) and platelet-derived growth factor BB (PDGF-BB) strongly increased [(35)S]-labeled proteoglycan levels. Tumor necrosis factor alpha further increased the stimulatory effect of PDGF-BB. PDGF-BB increased glycosaminoglycan (GAG) chain length as shown by molecular sieve chromatography after beta-elimination to release GAG chains. Nitric oxide was the only negative regulator of biglycan as evidenced by marked downregulation in response to DETA-NO ((Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate), a long acting nitric oxide donor and SNAP (S-nitroso-N-acetyl-l,l-penicillamine), which completely inhibited PDGF-BB-induced secretion of total [(35)S]-labeled proteoglycans and biglycan mRNA expression. Of note, the molecular weight of biglycan GAG chains was even further increased by NO donors compared to control and PDGF-BB stimulation. The current results suggest that in cardiac fibroblasts, biglycan is induced by a variety of stimuli including serum, thrombin and growth factors such as PDGF-BB and TGFbeta1. This response is counteracted by NO and enhanced by TNFalpha. Interestingly, both up- and downregulation were associated with posttranslational increase of GAG chain length.
The clavicle hook plate for Neer type II lateral clavicle fractures.
J Orthop Trauma. 2009 Sep; 23(8): 570-4Renger RJ, Roukema GR, Reurings JC, Raams PM, Font J, Verleisdonk EJOBJECTIVE: To evaluate functional and radiologic outcome in patients with a Neer type II lateral clavicle fracture treated with the clavicle hook plate. DESIGN: Multicenter retrospective study. SETTING: Five level I and II trauma centers. PATIENTS: Forty-four patients, average age 38.4 years (18-66 years), with a Neer type II lateral clavicle fracture treated with the clavicle hook plate between January 1, 2003, and December 31, 2006. INTERVENTION: Open reduction and internal fixation with the clavicle hook plate. Removal of all 44 implants after consolidation at a mean of 8.4 months (2-33 months) postoperatively. MAIN OUTCOME MEASUREMENTS: At an average follow-up of 27.4 months (13-48 months), functional outcome was assessed with the Constant-Murley scoring system. Radiographs were taken to evaluate consolidation and to determine the distance between the coracoid process and the clavicle. RESULTS: The average Constant score was 92.4 (74-100). The average distance between the coracoid process and the clavicle was 9.8 mm (7.3-14.8 mm) compared with 9.4 mm (6.9-14.3 mm) on the contralateral nonoperative side. We observed 1 dislocation of an implant (2.2%), 2 cases of pseudarthrosis (4.5%), 2 superficial wound infections (4.5%), 2 patients with hypertrophic scar tissue (4.5%), and 3 times an acromial osteolysis (6.8%). Thirty patients (68%) reported discomfort due to the implant. These implant-related complaints and the acromial osteolysis disappeared after removal of the hook plate. With all the patients, direct functional aftercare was possible. CONCLUSIONS: The clavicle hook plate is a suitable implant for Neer type II clavicle fractures. The advantage of this osteosynthesis is the possibility of immediate functional aftercare. We observed a high percentage of discomfort due to the implant; therefore, we advise to remove the implant as soon as consolidation has taken place.
An age- and sex-matched comparative study on both-bone diaphyseal paediatric forearm fracture.
J Child Orthop. 2009 Aug 23; Teoh KH, Chee YH, Shortt N, Wilkinson G, Porter DEPURPOSE: Intramedullary (IM) nailing and plating are recognised fixation methods for both-bone midshaft forearm fractures. Although both methods are effective, IM nailing has recently been the accepted operative treatment for the paediatric population. The aim of the study was to compare the differences in the radiographic and functional outcomes of an age- and sex-matched cohort of children following treatment by IM fixation or plate fixation with screws for an unstable both-bone diaphyseal fracture. METHODS: A retrospective study was conducted and 17 age- and sex-matched pairs of patients returned for a research review clinic. The average age of our patients was 11.6 years at follow up, with 11 boys and six girls in each group. The mean follow up was similar in both groups (IM 31.5 months, plating 31.8 months). RESULTS: Plating and IM nailing result in good or excellent functional and radiological outcomes. Radiographs at the review clinic showed complete healing in the plating group, with reconstitution of the radial bow. Three patients in the IM group did not regain the natural radial bow radiographically. There were no significant differences between both groups for maximum radial bow and its location (P > 0.05). However, the maximum radial bow was significantly different from normative values in both groups (P = 0.003 plate, P = 0.005 IM). No non-union or malunion was observed. There were no significant differences in the loss of forearm motion and grip strength between both groups. There was no difference in the Pediatric Orthopaedic Society of North America (POSNA) scores between both groups. The plating group had a significantly worse Manchester scar score than the IM group (P = 0.012). One major complication was observed in each group: osteomyelitis for IM fixation and ulnar never palsy for plating. CONCLUSION: Our study suggests that functional outcome is likely to be equivalent, regardless of which method of internal fixation is used.
Cell Therapy Enhances Function of Remote Non-Infarcted Myocardium.
J Mol Cell Cardiol. 2009 Aug 13; Moreno-Gonzalez A, Korte FS, Dai J, Chen K, Ho B, Reinecke H, Murry CE, Regnier MCell transplantation improves cardiac function after myocardial infarction; however, the underlying mechanisms are not well-understood. Therefore, the goals of this study were to determine if neonatal rat cardiomyocytes transplanted into adult rat hearts one-week after infarction would, after 8-10 weeks: 1) improve global myocardial function, 2) contract in a Ca(2+) dependent manner, 3) influence mechanical properties of remote uninjured myocardium and 4) alter passive mechanical properties of infarct regions. The cardiomyocytes formed small grafts of ultrastructurally maturing myocardium that enhanced fractional shortening compared to non-treated infarcted hearts. Chemically demembranated tissue strips of cardiomyocyte grafts produced force when activated by Ca(2+), whereas scar tissue did not. Furthermore, the Ca(2+) sensitivity of force was greater in cardiomyocyte grafts compared to control myocardium. Surprisingly, cardiomyocytes grafts isolated in the infarct zone increased Ca(2+) sensitivity of remote uninjured myocardium to levels greater than either remote myocardium from non-treated infarcted hearts or sham-operated controls. Enhanced calcium sensitivity was associated with decreased phosphorylation of cTnT, tropomyosin and MLC2, but not changes in myosin or troponin isoforms. Passive compliance of grafts resembled normal myocardium, while infarct tissue distant from grafts had compliance typical of scar. Thus, cardiomyocyte grafts are contractile, improve local tissue compliance and enhance calcium sensitivity of remote myocardium. Because the volume of remote myocardium greatly exceeds that of the grafts, this enhanced calcium sensitivity may be a major contributor to global improvements in ventricular function after cell transplantation.