Radiologic, mechanical, and histologic evaluation of 2 glenoid prosthesis designs in a canine model.

Aseptic loosening of glenoid components is a common problem associated with total shoulder arthroplasty. A new glenoid design aimed at improving fixation outcomes was compared with conventional keeled glenoids in weight-bearing canine shoulders. Radiographic, histologic, and mechanical tests were performed at 3 postoperative intervals (0, 3, and 6 months).

Bone morphogenetic protein but not transforming growth factor-beta enhances bone formation in canine diaphyseal nonunions implanted with a biodegradable composite polymer.

Background: The purpose of the present study was to create an effective bone-graft substitute for the treatment of a diaphyseal nonunion.

Methods: A standardized nonunion was established in the midportion of the radial diaphysis in thirty mongrel dogs by creating a three-millimeter segmental bone defect (at least 2 percent of the total length of the bone). The nonunion was treated with implantation of a carrier comprised of poly(DL-lactic acid) and polyglycolic acid copolymer (50:50 polylactic acid-polyglycolic acid [PLG50]) containing canine purified bone morphogenetic protein (BMP) or recombinant human transforming growth factor-beta (TGF-beta1), or both, or the carrier without BMP or TGF-beta1.

Guided tissue fabrication from periosteum using preformed biodegradable polymer scaffolds.

A successful tissue engineering method for bone replacement would imitate natural bone graft by providing the essential elements for new bone formation using synthetic scaffolds, osteogenic cell populations, and bone induction factors. This is a study of the suitability of various formulations of poly(DL-lactic-co-glycolic acid) (PLGA) foams to provide a tissue conducting scaffold in an ovine model for bone flap fabrication. Three formulations were used of different copolymer ratio and molecular weight.

Novel formulation of fibroblast growth factor-2 in a hyaluronan gel accelerates fracture healing in nonhuman primates.

Recent advances in understanding the biology of fracture healing and the availability of specific macromolecules has resulted in the development of novel treatments for injuries to bone. Fibroblast growth factor-2 or basic fibroblast growth factor (4 mg/ml), a potent mitogen, and hyaluronan (20 mg/ml), an extracellular matrix component, were combined into a viscous gel formulation intended for direct, percutaneous injection into fresh fractures. In an experimental primate fracture model, a bilateral 1-mm-gap osteotomy was surgically created in the fibulae of baboons.

Enamel epithelium expresses bone sialoprotein (BSP).

Bone sialoprotein (BSP) is a major non-collagenous extracellular matrix protein in bone and other mineralized connective tissues. BSP is synthesized and secreted by bone-, dentin- and cementum-forming cells. In this study we hypothesized that BSP may be also involved in enamel formation through its postulated role in matrix mineralization.

Neoplastic odontogenic epithelial cells express bone sialoprotein.

Bone sialoprotein (BSP) is synthesized and secreted by bone-, dentine- and cementum-forming cells and has been implicated in de novo bone formation and mineralization. In this study, we used histological sections of odontogenic neoplasms and performed immunohistochemical and in situ hybridization analyses. In ameloblastoma, BSP mRNA signals were seen in the neoplastic epithelial cells forming nests, strips and islands.

Repair of soft tissue to bone using a biodegradable suture anchor.

The medial collateral ligaments of 18 New Zealand rabbits were surgically detached from bone. In one knee, the ligament was repaired using a biodegradable suture anchor composed of a co-polymer of lactic and glycolic acid. The contralateral medial collateral ligament was not repaired.

Markers for macrophage and osteoclast lineages in giant cell lesions of the oral cavity.

Purpose: Giant cell lesions of the oral cavity are a well recognized entity. However, the histogenesis of these lesions is still the subject of controversy, with support for both histiocyte/macrophage and osteoclast origins being found in the literature. This study evaluated a set of peripheral giant cell lesions (PGCLs) and central giant cell lesions (CGCLs) for characteristics of both cell types to address this dilemma.

Evaluation of the Palmaz stent in the trachea and mainstem bronchi of normal dogs.

Objective: This study evaluates the efficacy of the Palmaz balloon expandable intraluminal stent in the trachea and mainstem bronchi of normal dogs.

Study Design: Effects of the stent were evaluated by physical examination, thoracic radiography, respiratory tract fluoroscopy and endoscopy, tracheal diameter measurement, postmortem examination, and airway histomorphometry.

Animals Or Sample Population: Ten normal beagle dogs.

Anatomic significance of magnetic resonance imaging findings in hip fracture.

This study was done to determine the histologic etiology for the linear black signal seen on magnetic resonance imaging at the site of proximal femoral fractures. No previous satisfactory explanation for this black line exists in the literature. To determine the pathologic etiology of this linear black signal, the magnetic resonance imaging appearances of osteotomies and fractures of proximal femora were correlated with gross and histologic appearances in 12 freshly frozen porcine hips.

Sublabral recess of the superior glenoid labrum: study of cadavers with conventional nonenhanced MR imaging, MR arthrography, anatomic dissection, and limited histologic examination.

Purpose: To evaluate size, location, and appearance of the sublabral recess of the superior glenoid labrum, which mimics a superior labral tear oriented in the anterior to posterior direction (SLAP) lesion with conventional magnetic resonance (MR) imaging, MR arthrography, gross dissection, and limited histologic evaluation.

Materials And Methods: Twenty-six cadaveric shoulder specimens that were freshly frozen were examined with nonenhanced MR imaging and with MR arthrography after intraarticular injection of dilute contrast material with gadolinium. In all specimens, the appearance of the superior glenolabral junction was categorized and was correlated to that seen at gross anatomic dissection.

Osteoblast migration on poly(alpha-hydroxy esters).

We investigated the migration of rat calvaria osteoblast populations on poly(alpha-hydroxy ester) films for up to 14 days to determine effects of substrate composition and culture conditions on the migratory characteristics of osteoblasts. Initial osteoblast culture conditions included cell colonies formed by seeding a high (84,000 cells/cm(2)) or low (42,000 cells/cm(2)) density of isolated osteoblasts on the polymer films, and bone tissue cultures formed by plating bone chips directly on the substrates. High density osteoblast colonies cultured and allowed to migrate and proliferate radially on 85:15 poly(DL-lactic-co-glycolic acid) (PLGA) films, 75:25 PLGA films, and tissue culture polystyrene controls demonstrated that the copolymer ratio in the polymer films did not affect the rate of increase in substrate surface area (or culture area) covered by the growing cell colony.

Periodontitis in the baboon: a potential model for human disease.

Advances in periodontics with respect to disease activity, microbiology and immunology have demonstrated the multifactorial nature of periodontal diseases. This serves to underscore the need for an ideal animal model for periodontal research. Non-human primates are most similar to man in comparison to other animal models.

Analysis of transforming growth factor beta and other cytokines in autoimmune exocrinopathy (Sjögren's syndrome).

Cytokines play a major role in tissue destruction caused by autoimmune dysregulation. In Sjögren's syndrome (SS) patients, salivary glands are the target organs for autoimmune tissue damage. In the present study, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to look for cytokine mRNA expressed in SS salivary glands.

The ingrowth of new bone tissue and initial mechanical properties of a degrading polymeric composite scaffold.

Trabecular bone deficiency causes a dilemma at surgery in a variety of clinical situations, including trauma, tumor resection, and reconstruction. A synthetic material to replace trabecular bone would be biocompatible, provide temporary mechanical strength to the reconstructed region, and serve as a scaffold upon which new bone could grow (i.e.

Localization of cytokines in cholesteatoma tissue.

Acquired cholesteatoma is associated with an intense inflammatory reaction with resultant tissue and bone destruction. Cytokines are molecules released by inflammatory cells at the site of infection and are potent mediators of inflammation and the immune response. Five cytokines, tumor necrosis factor-alpha, transforming growth factor-beta 1 and 2, and interleukin-1 and 6, were immunolocalized in human cholesteatoma epithelium and subepithelial stroma, with greater intensity of staining compared with noninflamed external auditory canal skin.