No abstract

The detection and identification of bacteria present in natural and industrial ecosystems is now entirely based on molecular systems that detect microbial RNA or DNA. Culture methods were abandoned, in the 1980s, because direct observations showed that <1% of the bacteria in these systems grew on laboratory media. Culture methods comprise the backbone of the Food and Drug Administration-approved diagnostic systems used in hospital laboratories, with some molecular methods being approved for the detection of specific pathogens that are difficult to grow in vitro. In several medical specialties, the reaction to negative cultures in cases in which overt signs of infection clearly exist has produced a spreading skepticism concerning the sensitivity and accuracy of traditional culture methods. We summarize evidence from the field of orthopedic surgery, and from other medical specialties, that support the contention that culture techniques are especially insensitive and inaccurate in the detection of chronic biofilm infections. We examine the plethora of molecular techniques that could replace cultures in the diagnosis of bacterial diseases, and we identify the new Ibis technique that is based on base ratios (not base sequences), as the molecular system most likely to fulfill the requirements of routine diagnosis in orthopedic surgery.

Desmoid tumor, desmoplastic fibroma, periosteal desmoid tumor, osteofibrous dysplasia and fibrous dysplasia are benign mesenchymal lesions arising in soft tissue or bone. Desmoid tumors, also known as aggressive fibromatosis or fibromatosis of soft tissue, may occur in extraabdominal, abdominal, or intra-abdominal locations. Desmoplastic fibroma and periosteal desmoid tumor, identical histologically, differ only by location. Desmoplastic fibroma and periosteal desmoid tumor are considered to represent the bone counterparts of desmoid tumors of soft tissue. A tumor-like proliferation of fibroosseous tissue is characteristic of osteofibrous dysplasia and fibrous dysplasia. The former is distinguished histologically by osteoblastic rimming of the bone trabeculae. Cytogenetic and molecular cytogenetic analyses of desmoid tumors are few and are particularly sparse or are nonexistent for desmoplastic fibroma, periosteal desmoid tumor, osteofibrous dysplasia, and fibrous dysplasia. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] To determine the frequency of trisomy 8 and trisomy 20 in additional desmoid tumor cases and to examine their presence in related fibrous lesions of bone, both standard karyotypic analysis and molecular cytogenetic analysis were performed on 22 representative specimens. Materials and Methods Cytogenetic AnalysisTwenty-two specimens (to include three desmoplastic fibromas, two periosteal desmoid tumors, nine desmoid tumors, four osteofibrous dysplasias, and four fibrous dysplasias) from 19 different patients were examined by traditional cytogenetic and molecular cytogenetic methodologies. A 0.5-to 1.0-cm 3 sample of each specimen was received for cytogenetic analysis. Standard culture and harvesting procedures were used that have been described previously. 4 Briefly, the tissues were disaggregated mechanically and enzymatically and then cultured in RPMI 1640 medium supplemented with 20% fetal bovine serum and 1% penicillin/streptomycin-L-glutamine (Irvine Scientific, Santa Ana, CA) for 3 to 5 days. Two to four hours before harvest, cells were exposed to Colcemid (0.02 g/ml). After hypotonic treatment (0.074 mol/L KCl for 30 minutes for flasks and 0.8% sodium citrate for 25 minutes for coverslips), the preparations were fixed three times with methanol/glacial acetic acid (3:1). Metaphase cells were banded with Giemsa trypsin. The karyotypes were expressed according to the International System for Human Cytogenetic Nomenclature 1995. 18

Knowledge of the MR imaging findings of chondroblastoma will allow accurate diagnosis and help avoid confusion with infection and aggressive neoplasms.

Intratumoral neovascularization determined at diagnosis does not correlate with long-term outcome in patients with nonmetastatic osteosarcoma. A prospective study is necessary to confirm these results.