Monoclonal antibody to human osteosarcoma: a novel Mr 26,000 protein recognized by murine hybridoma TMMR-2.

Three murine hybridomas (TMMR-1-3) were developed by repeated immunizations of mice with four different human osteosarcoma cell lines in an alternating sequence of inoculations. The monoclonal antibodies were screened for reactivities to cultured cell lines and tissue sections of osteosarcomas using flow cytometry and immunohistochemical techniques. TMMR-2 is a highly specific antibody (IgG1) that reacted with all 14 osteosarcoma tumors and eight human osteosarcoma cell lines tested, including the established human osteosarcoma cell lines HOS and Saos-2. Benign neoplastic cells from two osteoblastomas, osteoblasts from regions of reparative osteoid formation and neonatal new bone, are also reactive with TMMR-2. TMMR-1 has mesenchymal specificity while TMMR-3, although reactive with osseous differentiated cells, also reacted with mitotic cells of all cell types. Characterization of antigen structure by Western immunoblotting revealed that TMMR-2 reacted with a 100 degrees C heat labile mercaptoethanol-sensitive Mr 26,000 protein, and TMMR-3 recognized a mercaptoethanol-resistant Mr 97,000 protein whereas TMMR-1 reacted with a series of bands from 65,000 to 85,000 molecular weight, all of which were mercaptoethanol sensitive. TMMR-1 and TMMR-2 monoclonal antibodies showed complement-independent inhibition of [3H]thymidine incorporation into DNA, but did not exhibit cytotoxic activity. The results suggest that TMMR-2 is a specific antibody that recognizes an osteoblast/osteocyte surface antigen present in normal, reactive, and neoplastic disorders of bone. The inhibitory effects on DNA synthesis in cultured osteosarcoma cells by TMMR-2 indicate an important cell growth/proliferation role of this surface antigen. These monoclonal antibodies, in combination with other known antibodies, can be used to characterize mesenchymal cell surface antigenic structure and differentiation.

Repair of segmental bone defects in the rat: an experimental model of human fracture healing.

Bone repair models in animals may be considered relevant to human fracture healing to the extent that the sequence of events in the repair process in the model reflect the human fracture healing sequence. In the present study, the relevance of a recently developed segmental defect model in rat fibula to human fracture healing was investigated by evaluating temporal progression of rigidity of the fibula, mineral content of the repair site, and histological changes. In this model, a surgically created 2-mm-long defect was grafted with a 5-mm-long tubular specimen of demineralized bone matrix (DBM) by inserting it over the cut ends of the fibula. The temporal increase in rigidity of the healing fibula demonstrated a pattern similar to biomechanical healing curves measured in human fracture healing. This pattern was characterized by a short phase of rapidly rising rigidity during weeks 4-7 after surgery, associated with a sharp increase in the mineral content of the repair tissue. This was preceded by a phase of nearly zero rigidity and followed by a phase of slow rate of increase approaching a plateau. Histologically, chondroblastic and osteoblastic blastema originating from extraskeletal and subperiosteal (near fibula-graft junction) regions, infiltrated the DBM graft during the first 2 weeks. The DBM graft assumed the role of a "bridging callus." By weeks 6-8, most of the DBM was converted to new woven and trabecular bone with maximal osteoblastic activity and minimal endochondral ossification. Medullary callus formation started with direct new bone formation adjacent to the cortical and endosteal surfaces in the defect and undifferentiated cells in the center of the defect at 3 weeks. The usual bone repair process in rodents was altered by the presence of the DBM graft to recapitulate the sequential stages of human fracture healing, including the formation of a medullary callus, union with woven and lamellar bone, and recreation of the medullary canal.

Dietary flaxseed supplementation and experimental metastasis of melanoma cells in mice.

The present study investigated the effect of dietary supplementation of flaxseed, the richest source of lignans, on experimental metastasis of B16BL6 murine melanoma cells in C57BL/6 mice. Mice were fed a basal diet or the basal diet supplemented with 2.5, 5 or 10% flaxseed for 2 weeks before and after the intravenous injection of 0.75 x 10(5) melanoma cells. At necropsy, the number of tumors that developed in the lungs was counted, the cross-sectional area of tumors was measured and the volumes of tumors were calculated. The median number of tumors in mice fed the 2.5, 5 and 10% flaxseed-supplemented diets was 32, 54 and 63% lower than that of the controls, respectively. The addition of flaxseed to the diet also caused a dose-dependent decrease in the tumor cross-sectional area and the tumor volume. These results provide the first experimental evidence that flaxseed reduces metastasis and inhibits the growth of the metastatic secondary tumors in animals. It is concluded that flaxseed may be a useful nutritional adjuvant to prevent metastasis in cancer patients.

Demineralized bone matrix as a biological scaffold for bone repair.

Experimental models were created in rat fibula to represent impaired bone healing so that biological deficiencies that cause bone repair to fail or to be delayed may be investigated. These models consist of a 4-mm-long segmental defect, created in rat fibula by osteotomy, and fitted with a 7-mm-long tubular specimen of demineralized bone matrix (DBM) over the cut ends of the fibula. The experiments in this study involved various modifications of the DBM scaffold designed to reduce its osteoinductive activity: steam sterilization (sDBM), ethylene oxide sterilization (eoDBM), trypsin digestion (tDBM), and guanidine hydrochloride extraction (gDBM). Bone healing was evaluated by bending rigidity of the fibula and mineral content of the repair site at 7 weeks post-surgery. The sDBM scaffolds resorbed completely by 7 weeks and hence this model was a nonhealing negative control. Rigidities in the unmodified DBM and tDBM groups were comparable, whereas in the gDBM and eoDBM groups it was significantly reduced. Histologically, in the 4-mm defects repaired with unmodified DBM, direct and endochondral bone formation in the scaffold and the defect resulted in a neocortex consisting of woven and lamellar bone uniting the broken bone by 7 weeks post-surgery. We conclude that the eoDBM and gDBM groups represent failure or delay of the bone repair process when compared with the unmodified DBM group in which the process is analogous to normal bone healing.

Cytogenetic findings in 73 osteosarcoma specimens and a review of the literature.

Tumor-specific chromosomal abnormalities have been identified in several histologic subtypes of sarcomas. Characterization of recurrent chromosomal abnormalities has provided direction for molecular investigations of pathogenetically important genes. Cytogenetic reports of osteosarcoma, the most common primary malignant bone tumor, are relatively rare. In this study, 73 osteosarcoma specimens from 51 patients were cytogenetically analyzed following short-term culture. Clonal chromosomal abnormalities were detected in 47 and included one haploid specimen, 18 near-diploid specimens, 17 near-triploid, 8 near-tetraploid, 1 near-hexaploid, and 2 specimens with multiple clones of different ploidy levels. Examination of the present data and previously published data (111 clonally abnormal osteosarcoma specimens) reveals that chromosomal bands or regions 1p11-13, 1q10-12, 1q21-22, 11p15, 12p13, 17p12-13, 19q13, and 22q11-13 are most frequently rearranged and the most common numerical abnormalities are +1, -9, -10, -13, and -17. Partial or complete loss of the long arm of chromosome 6 also was seen in all cases of the present study and all previously published cases describing structural abnormalities of 6q. Parosteal osteosarcoma, a prognostically favorable osteosarcoma subtype, was characterized by the presence of a ring chromosome accompanied by no or few other abnormalities. Complex karyotypes were seen nearly exclusively in the high-grade lesions. These findings indicate that specific chromosomal bands and/or regions are nonrandomly involved in osteosarcoma and may provide useful clinical information.

Dietary supplementation of selenomethionine reduces metastasis of melanoma cells in mice.

The present study investigated the effect of dietary supplementation of selenomethionine on pulmonary metastasis of B16BL6 murine melanoma cells in C57BL/6 mice. Mice were assigned to four groups of 15 each. They were fed a basal AIN93G diet and the basal diet supplemented with 2.5 ppm or 5 ppm selenium as selenomethionine or with 2.5 ppm selenium as selenite for two weeks before and after the intravenous injection of 0.5 x 10(5) tumor cells. At necropsy, the number and size of tumors that developed in the lungs were determined. The number of mice that had > or = 11 tumors was 13, 8, 8, and 6 (p < 0.02 compared with the control), and the median number of lung tumors was 64, 14, 12 (p < 0.05 compared with the control), and 8 (p < 0.01 compared with the control) in the control group and the groups with 2.5 ppm and 5 ppm selenium as selenomethionine and 2.5 ppm selenium as selenite. Dietary supplementation of selenomethionine decreased tumor cross-sectional area and tumor volume compared with the controls. At the same dietary level, selenite had a greater inhibitory effect on tumor size than selenomethionine. These results demonstrate that dietary supplementation of selenomethionine reduced experimental metastasis of melanoma cells in mice and inhibited the growth of metastatic tumors that formed in the lungs. It is concluded that selenomethionine is an active form of selenium that reduces experimental metastasis.

Magnetic resonance imaging in planning limb-salvage surgery for primary malignant tumors of bone.

In defining the linear extent of a malignant tumor in a long bone, radiographs, computerized tomography, and scintigraphy are routinely employed, especially when non-ablative surgery is being considered. The drawbacks of these modalities in defining the true intracompartmental extent of disease within a bone can largely be overcome with the use of magnetic resonance imaging. We did a prospective analysis of magnetic resonance imaging in sixteen consecutive patients with a primary malignant tumor of a long bone, and it showed that this modality has clinical promise of being more precise than the other modalities in defining the true proximal and distal extent of a tumor in a long bone. Coronal images permit easier planning of surgical techniques for salvage of a limb using an allograft than do a multiplicity of transverse images.

Osteosarcomas arising on the surfaces of long bones.

Malignant bone-forming tumors that arise from the surfaces of long bones are far less common than those that arise from within bone. These surface osteosarcomas are clinically and radiographically similar, yet histologically they are quite distinct. In reviewing the literature, we classified the tumors according to three subgroups: parosteal (juxtacortical) osteosarcoma, periosteal osteosarcoma, and high-grade surface osteosarcoma. We also studied the clinical, radiographic, and histological findings in eighty patients who had been treated for an osteosarcoma over a forty-four-year period. Adequate follow-up data existed for forty-eight of the eighty patients. The duration of follow-up ranged from two to fifteen years after the initial operation (amputation or resection). Patients who had a parosteal osteosarcoma had the best prognosis; those who had a periosteal osteosarcoma, the next best; and those who had a high-grade surface osteosarcoma, the poorest. Because of these widely varying prognoses, the lesions require different treatment.

Magnetic resonance imaging of soft tissue masses: an evaluation of fifty-three histologically proven tumors.

Fifty-three histologically confirmed soft tissue masses in 48 patients were evaluated by magnetic resonance imaging (MR) and computerized tomography (CT). Twenty-three of these were malignant, twenty-three benign and seven of intermediate malignancy (all aggressive fibromatosis). The two procedures were compared for sensitivity and delineation of masses, their relationship to important neurovascular structures, their potential for histological diagnoses, their relative roles in influencing the surgical approach and the preferred modality in the follow-up for detection of tumor recurrence. Both modalities have their relative strengths and weaknesses. However, the superior contrast resolution of magnetic resonance imaging, its demonstration of lesions not clearly identified by CT, its pluridirectional capabilities and its ability to demonstrate large soft tissue tumors in a single coronal or sagittal plane makes it the preferred initial modality for evaluation of the soft tissue tumor of uncertain etiology and also in the follow-up of these patients. Despite MR's superiority in anatomically staging soft tissue tumors it, like CT, is of limited value in characterizing soft tissue sarcomas.

Closed treatment of displaced middle-third fractures of the clavicle gives poor results.

We evaluated 242 consecutive fractures of the clavicle in adults which had been treated conservatively. Of these, 66 (27%) were originally in the middle third of the clavicle and had been completely displaced. We reviewed 52 of these patients at a mean of 38 months after injury. Eight of the 52 fractures (15%) had developed nonunion, and 16 patients (31%) reported unsatisfactory results. Thirteen patients had mild to moderate residual pain and 15 had some evidence of brachial plexus irritation. Of the 28 who had cosmetic complaints, only 11 considered accepting corrective surgery. No patient had significant impairment of range of movement or shoulder strength as a result of the injury. We found that initial shortening at the fracture of > or = 20 mm had a highly significant association with nonunion (p < 0.0001) and the chance of an unsatisfactory result. Final shortening of 20 mm or more was associated with an unsatisfactory result, but not with nonunion. No other patient variable, treatment factor, or fracture characteristic had a significant effect on outcome. We now recommend open reduction and internal fixation of severely displaced fractures of the middle third of the clavicle in adult patients.

Malignant skeletal neoplasms in the geriatric patient.

Malignant neoplasms of the geriatric skeleton are either primary or metastatic in nature. The vast majority are metastatic to the skeleton from carcinomas. Rarely, a primary skeletal malignancy, usually a chondrosarcoma or a malignant fibrous histiocytoma, develops in the geriatric patient. This article discusses the presentation, evaluation, and management of these patients. Illustrative cases are presented.

Is there a link between fluoridated water and osteosarcoma?

To test the hypothesis that fluoride is a risk factor for osteosarcoma, a case control study compared the complete residential fluoride histories of osteosarcoma patients with matched hospital-based controls. Fluoridation was not found to be a risk factor for osteosarcoma in the study population. The trend in the data from this small sample study suggests the hypothesis that a protective effect may exist against the formation of osteosarcoma for individuals consuming fluoridated water.

Humeral shaft nonunions treated with fibular allograft and compression plating.

The present study is a retrospective review of the treatment of 12 humeral shaft nonunions by using an intramedullary allograft with compression plating. The average age of the patients was 61 years (range, 36-82 years). Eight cases involved the proximal shaft, 3 cases were at the mid-diaphyseal level, and 1 case was at the distal one third. Follow-up averaged 30 months (range, 12-96 months). Ten patients (83%) went on to uneventful healing at an average of 3 months after surgery. Two failures involving patients with multiple medical conditions occurred secondary to reinjury. Two cases of postoperative radial nerve neuropraxia involved the posterior approach to the humerus. Each resolved with no long-term residual morbidity. One patient developed postoperative adhesive capsulitis of the shoulder that resolved with nonoperative treatment. We feel that a fibular allograft, along with compression plating, can give satisfactory results for humeral shaft nonunions. This technique can be especially helpful in proximal humeral nonunions and in nonunions involving osteoporotic bone. Patients with multiple medical problems at risk for refalls should be protected until complete healing has occurred.