Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms by which PTH and thrombin mobilize intracellular Ca2+ (Cai2+) were examined in UMR 106-H5 rat osteosarcoma cells. Bovine PTH-(1-34) (24 pM to 240 nM) produced a dose-dependent increase in Cai2+ (EC50, 3 nM), which returned to baseline within 75 sec. Human alpha-thrombin produced an increase in Cai2+ (ECmax, 10 U/ml) which was similar to that of PTH with respect to both magnitude and time course. Chelation of extracellular calcium with 5.0 mM EGTA did not alter the Cai2+ response to either PTH or thrombin. When added together at maximally effective concentrations, PTH and thrombin produced additive effects on Cai2+ in the presence and absence of EGTA. The additive effects of PTH and thrombin on Cai2+ were confirmed at the single cell level, using laser-based image analysis. Bradykinin (1 microM) produced a significant increase in Cai2+ in UMR 106-H5 cells which was of lesser magnitude than the peak 2- to 3-fold increase elicited by PTH or thrombin. Preexposure of cells to 10 U/ml thrombin for 2 min abolished the Cai2+ response to bradykinin, whereas preexposure to 240 nM PTH had no effect on the Cai2+ response to bradykinin. Thrombin elicited a rapid increase in the accumulation of 3H-labeled inositol phosphates (IP2 and IP3) in UMR 106-H5 cells, with increases in [3H]1,4,5-IP3 detectable as early as 15 sec after the addition of thrombin. Bradykinin increased [3H]IP production to a lesser extent than thrombin, whereas PTH neither increased [3H]IP accumulation nor potentiated the [3H]IP response to thrombin. The results suggest that thrombin and bradykinin mobilize Cai2+ from a shared IP3-responsive calcium pool, whereas PTH may use signals in addition to 1,4,5-IP3 to mobilize calcium from a distinct cellular calcium pool. Alternatively, specific calcium compartmentalization exists, and there is differential coupling of these agonists to the 1,4,5-IP3/Cai2+ pathway.
Endocrinology 1991 Sep
PMID:Thrombin and parathyroid hormone mobilize intracellular calcium in rat osteosarcoma cells by distinct pathways. 187 83

Platelets have been shown to release osteonectin on thrombin stimulation. The origin of platelet osteonectin was unclear as it may have been synthesized by megakaryocytes or it may have been endocytosed from plasma as other platelet alpha-granule constituents are. Platelet osteonectin has a larger apparent molecular size than the bone species, although the molecular basis for this difference has not been elucidated. These two issues have been addressed here by (1) examining the potential for osteonectin biosynthesis in human megakaryocytes by demonstrating the presence of osteonectin mRNA in purified megakaryocytes, and (2) comparing the coding portion of osteonectin transcript in megakaryocytes to the size of its bone counterpart. Because of the limitations of cell population purity and in obtaining sufficient numbers of megakaryocyte cells for Northern analysis, we have used the polymerase chain reaction (PCR) to detect the presence of human osteonectin mRNA in megakaryocyte and megakaryocyte-depleted bone marrow cells. Isolation of RNA, cDNA synthesis, and PCR were performed on human osteosarcoma SaOS-2 cells, enriched megakaryocytes, and megakaryocyte-depleted cells. Restriction enzyme analysis of PCR DNA products confirmed the identity of the products as those encoding osteonectin for all three cell populations studied. In addition, the sizes of DNA indicate that osteonectin genomic DNA, nuclear RNA, or altered transcript were not amplified, and that the transcript from megakaryocytes is the same size as that from bone cells. These data suggest that the difference in protein size between platelet and bone osteonectin is due to posttranslational modification. To overcome the possibility that megakaryocyte signal originated from contaminating cells (less than 5% by cell count), all three cell populations were diluted to less than one cell per tube and PCR amplification was performed. Limiting dilution analyses demonstrated the presence of osteonectin mRNA in single megakaryocytes as well as in single cells from the cell population depleted of megakaryocytes, suggesting the capacity for osteonectin biosynthesis in all cells studied. The procedure we describe in this report can be used to examine specific characteristics of mRNA molecules in heterogeneous cell populations and in situations where only small quantities of cells can be obtained.
Blood 1991 Sep 01
PMID:Demonstration of osteonectin mRNA in megakaryocytes: the use of the polymerase chain reaction. 187 89

Three hundred and ninety-three patients with IIB osteosarcoma were treated at the author's institution between 1955 and 1986. In the first stage of the study, 88 patients were treated with surgery only. The five-year disease-free survival rate was 7%. In the second stage of the study, the efficacy of preventive chemotherapy after radical surgery was studied in 55 patients. The five-year disease-free survival rate was 34.4%. In the third stage of the study, the efficacy of combination therapy consisting of preoperative treatment, limb-saving surgery, and preventive chemotherapy was studied in 66 patients. The five-year disease-free survival rate was 35.5%. The authors examined results in 21 patients with Grade IV responses to evaluate the relationship between prognosis and morphogenic changes after preoperative radiotherapy and chemotherapy. The five-year disease-free survival rate was 57.9%. In the fourth stage of the study (conducted in 1986), two regimens of preoperative chemotherapy were initiated. The first regimen consists of intraarterial platinum infusions to patients with lower extremity bone damage. The second regimen consists of high-dose methotrexate infusions. The preliminary conclusion is that primary tumor damage is significantly more marked after intraarterial cisplatin infusion.
Clin Orthop Relat Res 1991 Sep
PMID:IIB osteosarcoma. Current management and survival statistics in the USSR. 188 28

Current management of osteosarcoma at the authors' institution involves intraarterial induction chemotherapy using intermittent cycles of cisplatin and doxorubicin (Adriamycin), surgical resection with limb-sparing wherever possible, and adjuvant systemic chemotherapy (high-dose methotrexate with retrieval and doxorubicin). Twenty cases treated in this way between May 1983 and May 1989 are reviewed. There were 18 Stage IIB osteosarcomas and two Stage IIB malignant fibrous histiocytomas. Chemotherapeutic effect was evaluated in the resected tumors. There was little correlation between the clinical response to the induction chemotherapy and cell necrosis present in the resected tumor mass. Wide resection margins were achieved in 17 cases, a minimal margin in two, and a contaminated margin in one. Radiotherapy was used in these three cases where resection margin was in doubt. There were two local recurrences in these three cases. Four patients have died of their disease, and there was one treatment-related death. Overall probability of survival in this group of 20 patients has been expressed by the Kaplan-Meier method as 58%.
Clin Orthop Relat Res 1991 Sep
PMID:IIB osteosarcoma. Current management, local control, and survival statistics--the Australian experience. 188 29

Postirradiation and Paget's osteosarcomas are high-grade malignancies. The five-year survival was only 10% in recent experience at the author's institution. Progressive pain is an important clinical feature in both conditions. Careful roentgenographic studies demonstrate cortical destruction and a soft-tissue mass in virtually all patients. Metastasis was present in 25% of both groups of patients at presentation. In contrast to previous series, more than 80% of the patients with postirradiation osteosarcoma had had irradiation for malignant entities and more than 70% had been treated with modern radiotherapy regimens (cobalt-60 or linear accelerator). Twice as many patients with postirradiation osteosarcoma were evaluated and treated in the 1980s than in the previous decade. The initial indication for irradiation often was carcinoma of the breast, uterus, or cervix, or lymphoma. Two-thirds of the patients had progressive disease that was not controllable within six months after diagnosis. Early detection may be the only effective means of improving survival with postirradiation or Paget's osteosarcoma. These patients require lifelong follow-up evaluations.
Clin Orthop Relat Res 1991 Sep
PMID:Survival and management considerations in postirradiation osteosarcoma and Paget's osteosarcoma. 188 30

Radiation and pagetic osteogenic sarcomas should be distinguished from classical osteogenic sarcoma. Both occur in older patients with significantly greater comorbidity. Roentgenographically, radiation osteogenic sarcoma is typically sclerotic, whereas pagetic osteogenic sarcoma is lytic and associated with pathologic fracture. Radical resections give the best result, local control, and survival. Chemotherapy has not proven effective to date. Improvements in tumor imaging and more intensive chemotherapy regimens may permit limb-sparing surgery. Overall results remain poor, with approximately 15% five-year survival in each condition.
Clin Orthop Relat Res 1991 Sep
PMID:Radiation and pagetic osteogenic sarcomas. 188 31

Telangiectatic osteosarcoma is a rare variant of osteosarcoma. In the original report from the authors' institution, a poor prognosis was noted. The authors have updated their experience with this entity. The prognosis for patients with telangiectatic osteosarcoma has improved remarkably. The prognosis in the present series seems to be the same as that for conventional osteosarcoma. Adjuvant chemotherapy seems to help in salvaging patients with metastatic disease. However, in this small series, survival of patients without metastasis is apparently not influenced by whether they received chemotherapy.
Clin Orthop Relat Res 1991 Sep
PMID:Telangiectatic osteosarcoma. 188 32

Osteosarcoma arising on the periosteal aspect of bone comprises a biologically heterogeneous group of neoplasms. The group as a whole may be referred to by a single descriptive term that emphasizes their common site of origin and underscores their malignant osteogenic potential: surface osteosarcoma. Its biologic heterogeneity may be approached via a number of avenues. Detailed description of individual tumors and grading are frequently employed. However, implementation of a classification system based upon reproducible clinical, roentgenographic, macroscopic, and histologic parameters is advantageous. The suggested classification system serves to clearly define parosteal and periosteal osteosarcoma, as well as recognize unusual variants. Most important, it defines therapeutic strategy. The classification system identifies low-grade, biologically indolent forms (i.e., parosteal osteosarcoma and periosteal osteosarcoma) that are best treated by surgery alone. At the same time, it recognizes high-grade forms with significant potential for life-threatening behavior (i.e., 'dedifferentiated' parosteal osteosarcoma and high-grade surface osteosarcoma) that are best managed by multimodality therapy incorporating chemotherapy and surgery.
Clin Orthop Relat Res 1991 Sep
PMID:Surface osteosarcoma. 188 33

Sixty patients with extremity osteosarcoma were treated with intraarterial cisplatin. This was followed by surgical resection (amputation or limb salvage) and postoperative adjuvant chemotherapy utilizing two different protocols. Seventy-five percent of patients achieved an initial response. Overall disease-free survival was 58%. The number of patients treated with limb-salvage surgery gradually increased to the extent that 80% of newly-registered patients achieved a response and were subjected to limb salvage. Disease-free survival was 48% in amputation and 68% in limb salvage. The only factors found to have prognostic significance in determining disease-free survival were extent of tumor destruction induced by preoperative chemotherapy and tumor size.
Clin Orthop Relat Res 1991 Sep
PMID:Intraarterial cisplatin in the management of stage IIB osteosarcoma in the pediatric and adolescent age group. 188 35

Canine osteosarcoma bears striking resemblance to osteosarcoma in humans. Similarities include the following: male sex predilection, large patient size, 75% or more affecting the appendicular site, metaphyseal location, generally unknown etiology, less than 10% of patients have documented metastasis at presentation, over 90% of tumors show high-grade histology, 75% of tumors show aneuploidy, the metastatic rate is 80% or more with amputation alone, the lung is the most common site of metastasis, and there is improved survival with adjuvant chemotherapy. The major differences are age of onset, with dogs being affected in middle age; greater frequency in the dog, with over 8000 new cases per year; and time to metastasis being faster in the dog than man. Canine osteosarcoma is a readily available and highly comparable spontaneously occurring cancer that should be useful in a better understanding of the same disease in humans.
Clin Orthop Relat Res 1991 Sep
PMID:Comparative aspects of osteosarcoma. Dog versus man. 188 36


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