Computerized measurements of radiographic anatomical parameters of the elbow joint in Bernese Mountain Dogs.

Objective: Comparison of two methods for evaluation of anatomical parameters of elbow joints in Bernese Mountain Dogs.

Study Design: Radiographic analysis.

Animals: Nine hundred and thirty-one radiographs of elbow joints from 305 Bernese Mountain Dogs.

N-methyl pyrrolidone as a potent bone morphogenetic protein enhancer for bone tissue regeneration.

In medicine, N-methyl pyrrolidone (NMP) has a long track record as a constituent in medical devices approved by the Food and Drug Administration and thus can be considered as a safe and biologically inactive small chemical. In the present study, we report on the newly discovered pharmaceutical property of NMP in enhancing bone regeneration in a rabbit calvarial defect model in vivo. At the cellular level, the pharmaceutical effect of NMP was confirmed, in particular, in combination with bone morphogenetic protein (BMP)-2, because NMP increased early and late markers for maturation of preosteoblasts and human bone marrow-derived stem cells in vitro.

Short-term and eight to 12 months results of a tibial tuberosity advancement as treatment of canine cranial cruciate ligament damage.

Objective: To describe the perioperative complications and the six weeks and eight to 12 months outcome of cases of canine cranial cruciate ligament damage treated with a tibial tuberosity advancement.

Methods: The medical records including the six weeks' postoperative re-evaluation and radiographs of dogs with a tibial tuberosity advancement (70 operated stifles) were analysed regarding the short-term outcome and the recorded complications. A questionnaire for the evaluation of the eight to 12 months outcome was sent to the owners and the answers tabulated.

Functionalization of polysulfide nanoparticles and their performance as circulating carriers.

We here present an evaluation of the carrier performance of nanoparticles that are biofunctional, i.e. derivatized to provide a controlled biological activity, and environmentally responsive, since they respond to the presence of oxidants.

Repair of critical size defects in the rat cranium using ceramic-reinforced PLA scaffolds obtained by supercritical gas foaming.

Bioresorbable scaffolds made of poly(L-lactic acid) (PLA) obtained by supercritical gas foaming were recently described as suitable for tissue engineering, portraying biocompatibility with primary osteoblasts in vitro and interesting mechanical properties when reinforced with ceramics. The behavior of such constructs remained to be evaluated in vivo and therefore the present study was undertaken to compare different PLA/ceramic composite scaffolds obtained by supercritical gas foaming in a critical size defect craniotomy model in Sprague-Dawley rats. The host-tissue reaction to the implants was evaluated semiquantitatively and similar tendencies were noted for all graft substitutes: initially highly reactive but decreasing with time implanted.

Recombinant protein-co-PEG networks as cell-adhesive and proteolytically degradable hydrogel matrixes. Part II: biofunctional characteristics.

We present here the biological performance in supporting tissue regeneration of hybrid hydrogels consisting of genetically engineered protein polymers that carry specific features of the natural extracellular matrix, cross-linked with reactive poly(ethylene glycol) (PEG). Specifically, the protein polymers contain the cell adhesion motif RGD, which mediates integrin receptor binding, and degradation sites for plasmin and matrix-metalloproteinases, both being proteases implicated in natural matrix remodeling. Biochemical assays as well as in vitro cell culture experiments confirmed the ability of these protein-PEG hydrogels to promote specific cellular adhesion and to exhibit degradability by the target enzymes.

In vivo targeting of dendritic cells in lymph nodes with poly(propylene sulfide) nanoparticles.

Delivery of biodegradable nanoparticles to antigen-presenting cells (APCs), specifically dendritic cells (DCs), has potential for immunotherapy. This study investigates the delivery of 20, 45, and 100nm diameter poly(ethylene glycol)-stabilized poly(propylene sulfide) (PPS) nanoparticles to DCs in the lymph nodes. These nanoparticles consist of a cross-linked rubbery core of PPS surrounded by a hydrophilic corona of poly(ethylene glycol).

Platelet-rich plasma and fibrin as delivery systems for recombinant human bone morphogenetic protein-2.

The aim of the present study was (1) to test whether or not platelet-rich plasma (PRP) or commercially available fibrin can increase bone regeneration compared with non-treated defects and (2) to test whether or not PRP or fibrin increases bone regeneration when used as a delivery system for recombinant human bone morphogenetic protein-2 (rhBMP-2). In 16 New Zealand White rabbits, four evenly distributed 6 mm diameter defects were drilled into the calvarial bone. The following five treatment modalities were randomly allocated to all 64 defects: (0) untreated control, (1) fibrin alone, (2) PRP alone, (3) fibrin with 15 microg rhBMP-2 and (4) PRP with 15 microg rhBMP-2.

Enhancement of bone healing using non-glycosylated rhBMP-2 released from a fibrin matrix in dogs and cats.

Objectives: To test a non-glycosylated recombinant human bone morphogenetic protein-2 (ngly-rhBMP-2)/fibrin composite, which has been shown experimentally to enhance healing of bone defects in rodents, in a clinical case series of dogs and cats undergoing treatment for fracture non-unions and arthrodesis.

Methods: A ngly-rhBMP-2/fibrin composite was applied in 41 sites in 38 dogs and cats for which a cancellous bone autograft was indicated, replacing the graft.

Results: Bridging of the bone defect with functional bone healing was achieved in 90 per cent of the arthrodesis and fracture nonunions treated in this manner.

Bone repair with a form of BMP-2 engineered for incorporation into fibrin cell ingrowth matrices.

Most growth factors naturally involved in development and regeneration demonstrate strong binding to the extracellular matrix and are retained there until being locally mobilized by cells. In spite of this feedback between cell activity and growth factor mobilization in the extracellular matrix, this approach has not been extensively explored in therapeutic situations. We present an engineered bone morphogenetic protein-2 (BMP-2) fusion protein that mimics such function in a surgically relevant matrix, fibrin, incorporated into the matrix until it is locally liberated by cell surface-associated proteases.

Bone healing in the rat and dog with nonglycosylated BMP-2 demonstrating low solubility in fibrin matrices.

A novel form of recombinant human bone morphogenetic protein-2 (BMP-2) was explored for effective incorporation and long-term retention into fibrin ingrowth matrices. The solubility of native BMP-2 is greatly dependent on its glycosylation. To enhance retention of BMP-2 in fibrin matrices, a nonglycosylated form (nglBMP-2), which is less soluble than the native glycosylated protein, was produced recombinantly and evaluated in critical-size defects in the rat calvarium (group n=6).

Synthetic extracellular matrices for in situ tissue engineering.

Cell interactions with the extracellular matrix play important roles in guiding tissue morphogenesis. The matrix stimulates cells to influence such things as differentiation and the cells actively remodel the matrix via local proteolytic activity. We have designed synthetic hydrogel networks that participate in this interplay: They signal cells via bound adhesion and growth factors, and they also respond to the remodeling influence of cell-associated proteases.

Endoscopic ultrasonography for the diagnosis of intrathoracic lesions in two dogs.

Endoscopic ultrasound was developed initially in humans to overcome limitations of conventional ultrasound in examining certain internal organs due to intervening bone or air-filled structures. Endoscopic ultrasound has been used most widely in investigation of the gastrointestinal tract in humans, but many intrathoracic applications as well as endoscopic ultrasound-guided techniques have recently been described. Mediastinal and pulmonary structures can be examined with endoscopic ultrasound since a high frequency ultrasound probe can be brought into close contact with the areas of interest via a transesophageal approach.

Repair of bone defects using synthetic mimetics of collagenous extracellular matrices.

We have engineered synthetic poly(ethylene glycol) (PEG)-based hydrogels as cell-ingrowth matrices for in situ bone regeneration. These networks contain a combination of pendant oligopeptide ligands for cell adhesion (RGDSP) and substrates for matrix metalloproteinase (MMP) as linkers between PEG chains. Primary human fibroblasts were shown to migrate within these matrices by integrin- and MMP-dependent mechanisms.

Synthetic matrix metalloproteinase-sensitive hydrogels for the conduction of tissue regeneration: engineering cell-invasion characteristics.

Synthetic hydrogels have been molecularly engineered to mimic the invasive characteristics of native provisional extracellular matrices: a combination of integrin-binding sites and substrates for matrix metalloproteinases (MMP) was required to render the networks degradable and invasive by cells via cell-secreted MMPs. Degradation of gels was engineered starting from a characterization of the degradation kinetics (k(cat) and K(m)) of synthetic MMP substrates in the soluble form and after crosslinking into a 3D hydrogel network. Primary human fibroblasts were demonstrated to proteolytically invade these networks, a process that depended on MMP substrate activity, adhesion ligand concentration, and network crosslinking density.