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We describe two patients with a distinctive histological condition which clinically and radiologically mimics fibrous dysplasia of the rib. Both patients presented with chronic pain confined to one rib. In each case their radiographs showed a solitary, fusiform expansion of a rib with variable calcification. Histologically the lesions were characterized by a central core of xanthomatous macrophages surrounded by cancellous bone that showed symmetrical and progressive maturation centrifugally towards the cortex, a pattern which distinguishes these lesions from the irregular pattern of fibrous dysplasia.

The authors report two patients who presented with a mass in their thigh muscles. On the basis of the histologic appearance, a diagnosis of small cell malignancy was made. Further investigations including electron microscopy and immunoperoxidase techniques were necessary to accurately identify these tumors as lymphoma. Intramuscular lymphoma is rare, but it should be considered in the differential diagnosis, when the tumor consists of small cells. Special techniques are mandatory for a definitive diagnosis.

The authors studied histologically six of 35 massive osseous or osteochondral transplants that had been inserted following radical resection of musculoskeletal malignancies. The six transplants consisted of three allografts removed because of infection within 12 weeks following insertion and two allografts and one vascularized autograft resected between 52 and 72 weeks because of recurrent tumor. The infected allografts were necrotic and showed extensive osteomyelitis and septic arthritis. Focal areas of cartilage still had chondrocytes. The two non-infected allografts were also necrotic, and host bone had grown into donor bone at the graft--host interface. The vascularized autograft was viable. Articular cartilage was present in only one of the non-infected allografts and was necrotic. Ultrastructurally, allograft cartilage, although necrotic, showed marked destruction of the matrix only when infected. Allograft bone seems to act purely as a strut, inciting little immune response. It is unable to respond to infection and has little osteoinductive ability. Vascularized autograft, in contrast, appeared to contribute to graft union. Articular cartilage can survive transplantation but may become necrotic and undergo marked degeneration when infected. The histologic findings and clinical courses support the conclusion that graft failure within 72 weeks after transplantation is not due to immunologic rejection.

Certain nuclear morphometric features measured in breast tumor tissue have been shown to predict the prognosis of breast cancer patients. However, the application of these features to predicting risk of breast cancer development has received little attention. We conducted a case-control study to evaluate nuclear morphometric features in benign breast tissue in association with subsequent breast cancer risk. The study was nested within a cohort of 4,888 women with a histopathologic diagnosis of benign breast disease (BBD) and involved 61 cases and 71 controls, amongst whom there were 53 matched case-control sets. Conditional logistic regression models were fitted to assess various measurements of nuclear size and nuclear shape factors in relation to subsequent breast cancer risk. In multivariate analysis, subsequent breast cancer risk was positively associated with a nuclear shape factor that takes the shortest nuclear axis and the longest nuclear axis into consideration simultaneously (highest quartile versus lowest 3 quartiles: odds ratio = 3.07, 95% confidence limits = 1.61, 5.84). In contrast, there was no alteration in subsequent breast cancer risk in association with nuclear size features and other shape factors. In conclusion, our study results suggest that the shape factor that takes both the shortest nuclear axis and the longest nuclear axis into consideration might be of value to predict subsequent development of breast cancer among women with BBD.

Summary Objective To determine if membrane type-1 matrix metalloproteinase (MT1-MMP) will respond to cyclic compression of chondrocytes grown in vitro and the regulatory mechanisms underlying this response. Methods Cyclic compression (30 min, 1 kPa, 1 Hz) was applied to bovine chondrocytes (6–9-month-old animals) grown on top of a biodegradable substrate within 3 days of initiating culture. Luciferase assays using bovine articular chondrocytes were undertaken to demonstrate the mechanosensitivity of MT1-MMP. Semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) and western blot analysis were used to establish the time course of gene and protein upregulation in response to cyclic compression. The regulation of MT1-MMP was assessed by electrophoretic mobility shift assays, RT-PCR and western blot analysis. As well, an MT1-MMP decoy oligonucleotide and an extracellular signal-regulated kinase 1/2 (ERK1/2) pharmacological inhibitor were utilized to further characterize MT1-MMP regulation. Results After cyclic compression, MT1-MMP showed a rapid and transient increase in gene expression. Elevated protein levels were detected within 2 h of stimulation which returned to baseline by 6 h. During cyclic compression, phosphorylation of the mitogen activated protein kinase ERK1/2 increased significantly. This was followed by increased gene and protein expression of the transcription factor; early growth factor-1 (Egr-1) and Egr-1 binding to the MT1-MMP promoter. Blocking Egr-1 DNA binding with a decoy MT1-MMP oligonucleotide, downregulated MT1-MMP gene expression. The ERK1/2 inhibitor U0126 also reduced Egr-1 DNA binding activity to MT1-MMP promoter sequences and subsequent transcription of MT1-MMP. Conclusions These data suggest that cyclic compression of chondrocytes in vitro upregulates MT1-MMP via ERK1/2 dependent activation of Egr-1 binding. Delineation of the regulatory pathways activated by mechanical stimulation will further our understating of the mechanisms influencing tissue remodeling.

Forty-one women with idiopathic postmenopausal osteoporosis have been followed for 2 years after initiation of sodium fluoride at 40–50 mg/day, given together with a daily calcium supplement of 1 gram and vitamin D2, at 50,000 IU weekly. Histological and histomorphometric analyses were done on bone biopsies taken prior to and after 1 year of treatment (mean 1.25 ± 0.35 years). Thirty patients (74%) developed the histological fluoride effect of hyperosteoidosis, while the remaining 11 patients (26%) had no change from pretreatment biopsies. Hyperosteoidosis was based on increased values for osteoid volume and/or thickened osteoid with >3 lamellar bands. Based on previously reported findings, this histological evidence of hypersoteoidosis within 12–18 months of initiation of therapy provides a useful predictor of ultimate satisfactory fluoride response in terms of bone mineral accretion. No increases in bone mass (measured by neutron activation analysis) were observed at the time of the posttreatment biopsy but, according to this previous work, increases are anticipated over a further 2–3 years of treatment. Factors affecting the development of hyperosteoidosis were analyzed. Hyperosteoidosis was associated with a significantly higher dose of sodium fluoride and a significantly higher level of bone fluoride retention but without significant increase in fasting serum fluoride. Results suggest that fluoride retention depends not only on fluoride dose but also on body size, renal function, and intestinal absorptions of calcium and fluoride. There were no differences in the initial investigations between patients with and without hyperosteoidosis, with respect to age, years of postmenopause, estrogen use, initial biochemistry, or initial bone histology. In this study, fluoride dose and bone fluoride retention were the only identified factors that influenced the histological fluoride response of hyperosteoidosis.

A microsurgical model was developed to study the transplantation of large sections of vascularized skeletal tissue in inbred rats. A modified vascularized leg graft, consisting of the distal femur, knee joint, and intact tibia, with the associated musculature, was orthotopically transplanted in Fischer F344 rats. The femoral artery and vein were anastomosed by means of a microsurgical technique. Skin coverage was accomplished with recipient skin. In the studies reported here, syngeneic grafts were followed for up to twelve months by means of clinical examinations, X-rays, bone scans, and histologic studies. The bone and joint tissues not only survived but grew; the joints functioned and appeared to be histologically normal. Nonvascularized control grafts rapidly developed necrosis and osteomyelitis that lead to death of the recipients. Nonvascularized knee joint grafts, which were performed as additional controls, were better tolerated than nonvascularized limb grafts but they developed progressive degenerative changes. Thus, only the vascularized grafts restored optimal limb function. This model will be useful for exploring the feasibility and potential uses of large vascularized grafts of skeletal tissue.

This study describes radiographic and MR imaging features of primary leiomyosarcoma of bone.Twelve patients (five men and seven women, 39-79 years old) who were treated at two oncology centers for primary leiomyosarcoma of bone involving the femurs, tibia, ilium, and inferior pubic ramus were studied. None of the patients had preexisting disease or disease elsewhere at the time of diagnosis. Pathologic diagnosis was obtained in all patients.Radiographs of all patients showed a matrix that was exclusively osteolytic. In long bones (seven patients), the tumor had an average length of 11 cm (range, 7-17 cm) and revealed an elongated configuration. In the pelvis (five patients), the average length of the tumor was 10 cm (range, 4-15 cm). MR imaging confirmed an intramedullary lesion in all patients, with extension into the soft tissues in eight patients and no identifiable soft-tissue mass in the remaining four patients. Four of the five pelvic tumors had a prominent soft-tissue mass, whereas only four of the seven long bone lesions revealed a soft-tissue mass that was, in all instances, small. The tumor was hypointense on T1-weighted images and showed heterogeneous signal intensity on T2-weighted conventional and fast spin-echo sequences. We saw low signal intensity (short T2) in eight patients and homogeneous hyperintense signal intensity in one patient. In the remaining three patients, T2-weighted spin-echo sequences obtained with fat saturation showed high signal intensity (long T2) in the tumors.Primary leiomyosarcoma of bone is a rare tumor that on radiography reveals no matrix and on MR imaging reveals areas of T2 shortening in relation to fat on conventional and fast spin-echo sequences.

Fresh cadaveric osteochondral fragment allografts were used to replace damaged articular surfaces of knee joints. Of the original 100 patients, 22 experienced graft failure necessitating graft removal. From these patients, a total of 44 osteochondral allografts were extirpated between 12 and 84 months after insertion. These were examined radiologically, histologically, and ultrastructurally. The bone and bone marrow were necrotic and had undergone variable replacement by host bone, which appeared to be independent of the duration of the graft. The articular cartilage showed degenerative changes ranging from fibrillation to erosion. Viable donor cartilage was present as late as seven years, proving that fresh graft cartilage can survive transplantation. Host bone interfaced with the cartilage, but in 14 grafts there was focal invasion of the cartilage. In some grafts, pannus formation with resorption of cartilage was evident. There was no histologic evidence of transplant rejection. This study is encouraging because hyaline cartilage has been shown to survive for as long as seven years and because bone can be replaced in a homogeneous fashion if the correct biomechanical conditions are met.

s / Osteoarthritis and Cartilage 21 (2013) S63–S312 S121 214 ROLE OF INSULIN IN SOX9 MEDIATED COL2A1 EXPRESSION IN PASSAGED ARTICULAR CHONDROCYTES N. Ahmed, D. Taylor, R. Kandel. SLRI, Toronto, ON, Canada Purpose: One of the factors preventing clinical application of regenerative medicine to degenerative cartilage diseases is a suitable source of cells. Cartilage tissue is sparsely cellular and chondrocytes are the only cell type but under in vitro culture conditions they lose their phenotype along with the ability to generate hyaline cartilaginous tissue. Here we describe a reliable serum and growth factor free culture system to reverse this change in phenotype. Methods: Bovine articular chondrocytes (BAC) were passaged twice to allow for cell number expansion (P2) and cultured at high density on 3D collagen type II-coated membranes in media supplemented with ITS+ with 4.5g/l glucose, proline and 10-8 M dexamethasone (SF3D). Cultures were grown for up to 4 weeks. Inhibition studies were initiated on day 2 with 100uM HNMPA-(AM3). For FACS cells were harvested with Trypsin, stained with antibodies reactive with CD105-PE or CD44PE (eBioscience, US) and analyzed by EPICS XL FACS and Kaluza analysis software (Beckman Coulter, US). ChIP-qPCR was carried out after in-situ cross-linking with 0.75% formaldehyde. Cells were sonicated in 1% Triton-100 and 1% SDS lysis buffer (Vibracell 30sec ON and 60sec OFF, 20x) and 250-900 bp DNA fragmentation was confirmed by agarose gel electrophoresis. Purified DNA was analyzed by qPCR using primers within the enhancer region of COL2A1. For immunoprecipitation cells were extracted in Ripa buffer and incubated with Sox9 antibody, the immune complex was harvested with Protein A/G beads. Extracts were immunoblotted with antibodies reactive with Sox6 and Med12. Results: 99% of P2 cells in monolayer culture were CD44+ and 40% were CD105+. They showed differential gene expression with high type 1 collagen and low type II collagen. Gene expression of other cartilage associated genes was lower in P2 cells when compared with the primary P0 chondrocytes. When placed in SF3D the P2 cells expressed chondrogenic genes and accumulated extracellular matrix (ECM) rich in proteoglycans (PGs) and type II collagen. Decreasing insulin receptor (IR) with HNMPA-(AM3) inhibited collagen and PGs synthesis and reduced expression of col II, col XI, IR and IGF1R genes as well as Sox6 and 9 proteins. Co-IP and ChIP analysis on inhibited cells showed binding of co-activators Sox6 and Med12 with Sox9 but reduced Sox9Col2A1 binding. Figure 1. Photomicrographs of the tissue formed by P2 when cultured in SC3D culture show no matrix accumulation (far left panel) SF3D show accumulation of matrix rich in PGs evident by Toluidine Blue staining (second panel). SF3D tissue stained positively for collagen type II (red) and were predominantly negative for collagen type I (green) (third panel) similar to native cartilage tissue stained with the same antibodies (fourth panel). Conclusions: Here we describe a novel serum/ xenogeneic compound/ growth factorfree culture system which promotes hyaline-like cartilage tissue formation by insulin mediated regulation of Sox9-Col2A1 binding. This is a critical step towards the ultimate goal of developing autologous patient specific tissue engineered hyaline-like cartilage tissue suitable to use for repair/replacement of damaged articular cartilage. The suitability of this system for use in regenerative medicine approaches needs to be examined in vivo. Acknowledgements: Supported by DoD. Ă 215 JOINT DISTRACTION RESULTS IN CLINICAL AND STRUCTURAL IMPROVEMENT OF HAEMOPHILIC ANKLE ARTHROPATHY: A SERIES OF THREE CASES L. van Vulpen, M.E. van Meegeren, K. van Veghel, P. de Kleijn, P.M. van Roermund, D.H. Biesma, G. Roosendaal, S.C. Mastbergen, F.P. Lafeber;. UMC Utrecht, Utrecht, The Netherlands Purpose: Joint distraction is extensively studied in osteoarthritis and found to be very effective in diminishing pain and improving joint function. Uniquely, this treatment also results in actual joint tissue repair as proven by MRI, X-ray and biomarker analyses (Intema et al., Ann Rheum Dis 2011). With this treatment a prosthesis or arthrodesis can be delayed which is especially of value for younger patients (