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R M Terek

Publications and source records attributed to R M Terek.

At least 19 recordsLinked to original sources
PubMed2001

Gadolinium inhibits thymidine incorporation and induces apoptosis in chondrocytes.

Magnetic resonance arthrography. a procedure where contrast agents containing gadolinium are administered intra-articularly, has become a useful tool in musculoskeletal diagnosis. Although considered safe for systemic use, toxicities in some tissues have been identified for both free gadolinium ion and the gadolinium chelates used as contrast. In this study, the effects of short-term exposure of articular chondrocytes to gadolinium contrast were examined by assaying for proteoglycan synthesis, cell proliferation, and apoptosis. Bovine chondrocytes were grown in monolayer culture and exposed to gadodiamide for 16 h. Proteoglycan synthesis was measured through incorporation of radiolabeled sulfate. Uptake of radiolabeled thymidine assessed cell proliferation. Apoptosis was detected using the TUNEL assay, where DNA strand breaks characteristic of apoptosis are labeled with fluorescent nucleotide. Proteoglycan synthesis was stimulated by lower dose exposure to gadodiamide. At higher doses, proteoglycan synthesis returned to baseline. Cell proliferation decreased following exposure to gadodiamide in a dose-dependent manner. Chondrocyte apoptosis was induced in a dose-dependent manner. Further work is needed to determine if these in vitro effects are present in the intact joint.

Animals↗
PubMed2000

The role of preoperative chemotherapy in the treatment of infantile fibrosarcoma.

Infantile fibrosarcoma (IFS) is a rare tumor most often affecting the extremities of infants and young children. Unlike its adult counterpart, IFS has a low potential for metastatic spread, and surgical extirpation alone has therefore resulted in an excellent prognosis. The amputation rate, however, exceeds 50%. The dramatic response in 2 recent cases to preoperative chemotherapy, given in an attempt to avoid amputation, prompted this report and a review of the literature.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Multidrug resistance-1 and p-glycoprotein in human chondrosarcoma cell lines: expression correlates with decreased intracellular doxorubicin and in vitro chemoresistance.

We report on two chondrosarcoma cell lines, FS and AQ, that may be used as models of multidrug resistance in chondrosarcoma. Multidrug resistance-1 expression was assayed with reverse transcription-polymerase chain reaction. Immunostaining for the multidrug resistance-1 product, P-glycoprotein, was performed with the monoclonal antibody C494. Intracellular levels of doxorubicin were measured by fluorescent emission at 590 nm after 1 hour of incubation with the agent and again after 1, 2, and 4-hour washout periods. Chemosensitivity was assayed by staining micropellet cultures of AQ and FS cells with fluorescein acetate before and after the cells were exposed to varying doses of doxorubicin for 48 hours. Cytotoxicity was assessed by comparison of computer-processed images before and after treatment. The FS cell line was positive for multidrug resistance-1 expression, stained heavily for P-glycoprotein, and had significantly lower intracellular levels of doxorubicin than the AQ cell line, which was negative for multidrug resistance-1 and P-glycoprotein. Chemosensitivity testing showed that the FS cell line was significantly more resistant to doxorubicin than was the AQ cell line at all doses tested. Our results show that multidrug resistance-1 expression in a human chondrosarcoma cell line results in resistance to doxorubicin in vitro.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Chemotherapy and P-glycoprotein expression in chondrosarcoma.

Chondrosarcomas are alleged to be resistant to chemotherapy. A retrospective review of our experience primarily with dedifferentiated chondrosarcomas treated with chemotherapy was performed to reevaluate the efficacy of chemotherapy for this tumor. There were 18 patients: 14 stage IIB and four stage III. Seventeen patients had dedifferentiated chondrosarcoma. The median age at diagnosis was 57 years. Fourteen of the patients underwent wide excision of the tumor, two underwent amputation, and two had no surgery. The femur and the pelvis were the most common locations of the primary tumor. Chemotherapy for 11 of the patients consisted of cisplatin and doxorubicin. Survival was analyzed with the Kaplan-Meier method; the median survival was 12 months. The hypothesis that chondrosarcomas express P-glycoprotein was tested. Expression of P-glycoprotein was evaluated by immunostaining with use of the C494 and C219 antibodies on 41 benign and malignant cartilage tumors, six of which were from the patients in the chemotherapy group. Immunostaining revealed that 37 of 41 cartilage tumors expressed P-glycoprotein. The rate of survival of patients with high-grade chondrosarcoma treated with chemotherapy is poor. P-glycoprotein expression is common in benign and malignant cartilage lesions. The lack of response to chemotherapy may be related to the expression of P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

p53 mutations in chondrosarcoma.

Chondrosarcoma is a primary bone tumor that has several different grades and variants. We evaluated 48 chondrosarcomas for p53 overexpression and p53 mutations. p53 expression was evaluated with immunohistochemistry using monoclonal antibodies PAb421, PAb1801, and PAb240. p53 mutations were identified with single-strand conformational polymorphism (SSCP) and DNA sequencing in selected cases. Immunohistochemistry revealed nuclear staining with PAb421 and PAb1801 in the spindle cell portion of one dedifferentiated chondrosarcoma. SSCP analysis was abnormal only in the case with positive immunostaining and localized the mutation to exons 7 and 8. DNA sequence analysis identified a point mutation of G to C in codon 276, resulting in an amino acid substitution of proline for alanine. This point mutation has been reported previously in other tumors but not in chondrosarcoma. Assimilation of our results with previous studies suggests that p53 mutations are present in a minority of chondrosarcomas but when present, are in higher grade chondrosarcomas and their variants.

Bone Neoplasms↗
PubMed1998

Long bone surface osteomas: imaging features that may help avoid unnecessary biopsies.

OBJECTIVE: Our purpose is to show that a combination of imaging techniques and periodic radiologic follow-up offers an alternative to biopsy in certain patients with long bone surface osteomas. CONCLUSION: Asymptomatic lesions that are consistent with osteoma on a combination of imaging studies can be followed up clinically and radiographically, allowing patients to avoid unnecessary biopsies.

Adult↗
PubMed1997

Sarcoma of bone.

Multiagent chemotherapy and limb salvage surgery are two major advances which have occurred over the last twenty years in the treatment of primary bone sarcoma. Limb salvage as an alternative to amputation results in improved quality of life without a compromise in cure. The complications of limb salvage continue to decrease while the durability of the reconstructions continues to improve. Chemotherapy has dramatically improved long-term survival, particularly in children.

Biopsy↗
PubMed1996

Treatment of femoral Ewing's sarcoma.

BACKGROUND: The treatment of Ewing's sarcoma consists of chemotherapy for systemic and local disease. However, the role of radiation therapy, and/or surgical resection for definitive local treatment has yet to be determined. METHODS: A retrospective review of 32 patients (24 males and 8 females) treated for femoral Ewing's sarcoma between 1970 and 1985 was performed. Patients were divided into 3 treatment groups: chemotherapy and radiotherapy (CR) (10); chemotherapy and surgery (CS) (9); and chemotherapy, surgery, and radiotherapy (CSR) (13). Patients in the CR group received a mean of 5320 centigray (cGy) of radiation and patients in the CSR group received a mean of 3590 cGy. Multiagent cyclophosphamide/doxorubicin based chemotherapy was used in all cases. Surgery consisted of wide resection or amputation. RESULTS: Patients in the CR group had a higher risk of local recurrence than patients in the CS and CSR groups (P=0.02, log rank). The combination of local recurrences and treatment complications necessitated surgery for 7 of 10 CR patients, whereas 1 of 9 and 4 of 13 in the CS and CSR groups required additional surgery. The median survival for the entire group was 39 months. Minimum follow-up for surviving patients was 45 months. Five-year survival consisted of 1 of 10 patients in the CR group, 2 of 9 in the CS group, and 7 of 13 in the CSR group. There were no statistically significant differences among the three survival curves. Tumor location within the femur was a significant prognostic variable. Distal femoral location had a survival advantage compared with proximal and mid-femur locations (P = 0.049, log rank). CONCLUSIONS: Femoral Ewing's sarcoma remains a disease with a poor prognosis. Radiation alone for local treatment results in a high rate of local recurrence and complications. Our current local treatment strategy for femoral Ewing's sarcoma includes surgery in all and adjuvant radiotherapy in many of the patients.

Adolescent↗
PubMed1995

Platelet-derived growth factor in fibrous musculoskeletal disorders: a study of pathologic tissue sections and in vitro primary cell cultures.

Despite the great variability in the clinical behavior of fibrous lesions of the musculoskeletal system, they are composed of cytologically similar fibrocytes. Receptors for estrogen or progesterone, or both, are present in some of these lesions and some increase their rate of growth during periods of high levels of sex steroid hormones. The platelet-derived growth factor-B (PDGF-B) proto-oncogene encodes the B chain of PDGF, a mitogen for fibrocytes. Tissue from aggressive fibromatosis, fibrous dysplasia, plantar fibromatosis, and recurrent plantar fibromatosis was analyzed with use of the polymerase chain reaction and in situ hybridization for the expression of PDGF-B and PDGF beta receptor. Cell culture was used to determine if estrogen and progesterone stimulation modulated the expression of PDGF-B. Aggressive fibromatosis, fibrous dysplasia, and recurrent plantar fibromatosis expressed PDGF-B; plantar fibromatosis, normal plantar fascia, normal fascia lata, and mature scar did not. All of the tissues expressed PDGF beta receptor. The level of expression in aggressive fibromatosis and fibrous dysplasia was four times that in the recurrent plantar fibromatosis. Estrogen and progesterone stimulation in aggressive fibromatosis resulted in an increase in the level of expression. Therefore, the detection of PDGF-B may be an adjunct in the pathologic identification of locally invasive lesions. Its production may be a common mechanism leading to a fibroproliferative response through deregulation of the control of growth by both paracrine and autocrine mechanisms.

Base Sequence↗
PubMed1995

The expression of platelet-derived growth-factor gene in Dupuytren contracture.

Dupuytren contracture is a disease of the palmar fascia characterized by nodular fibroblastic proliferation; its etiology and pathogenesis are poorly understood. Growth factors are polypeptides that regulate cell growth and differentiation and extracellular matrix production. Platelet-derived growth factor is known to cause fibroblastic proliferation, and it may be involved in the pathogenesis of Dupuytren contracture. The purpose of this study was to determine if the gene for the B chain of platelet-derived growth factor is expressed in Dupuytren contracture. Tissue from patients who had Dupuytren disease was examined immunohistochemically with the 5B5 antibody, which is a marker for fibroblasts. Polymerase chain reaction, gel electrophoresis, Southern blotting, and in situ hybridization were also used to study gene expression in the tissue as well as in normal fascia, A172 cells, and MRC5 cells. Total cellular RNA was extracted from tissue and cells. Polymerase chain reaction was done with oligonucleotide primers complementary to a portion of the platelet-derived growth-factor-B and platelet-derived growth-factor-receptor genes. The platelet-derived growth-factor-B gene was expressed in all six specimens from the patients who had Dupuytren contracture as well as in the A172 cells, but not in the normal fascia lata or the MRC5 cells. These results were confirmed with Southern blotting of the products of the reaction with a platelet-derived growth-factor-B probe. The gene for the platelet-derived growth-factor receptor was expressed by all tissues and cells studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Southern↗
PubMed1995

Treatment of soft-tissue sarcomas of the hand.

We studied the clinical features, radiographic and pathological findings, treatment, and results for twenty-three patients who had been managed for a soft-tissue sarcoma of the hand between 1982 and 1990. The ages of the patients ranged from sixteen to seventy-six years (median age, thirty-one years). The most common clinical finding was a small, painless soft-tissue mass. Twenty of the tumors were high-grade, and eighteen were less than five centimeters in diameter. The most common diagnosis was synovial sarcoma, which was identified in eight patients. Leiomyosarcoma, rhabdomyosarcoma, and malignant fibrous histiocytoma developed in three patients each; epithelioid sarcoma, in two patients; and angiosarcoma, liposarcoma, neuroectodermal tumor, and clear-cell sarcoma, in one patient each. Curative wide excision or amputation was attempted in twenty-two patients; the margins were positive for tumor cells in eight, and local recurrence was seen in nine. Of the twenty-three patients, fourteen had survived, without evidence of disease, after a median duration of follow-up of forty-nine months, and nine had died of disease. The median rate of survival did not differ significantly on the basis of the size or grade of the tumor or the use of adjuvant treatment. However, the rate of survival of the patients who had a soft-tissue sarcoma of the hand that was less than five centimeters in diameter was significantly lower (p = 0.0008) than that of 152 patients who had a similar tumor at another site in an extremity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Soft-tissue sarcomas of the hand and wrist.

Treatment of soft-tissue sarcomas of the hand cause the ultimate confrontation between oncologic outcome and function. The management of hand sarcomas is based on knowledge of the specific biology and location of each tumor. This article reviews the multimodality management of soft-tissue sarcomas of the hand and wrist.

Biopsy↗
PubMed1994

Tumors of the elbow and forearm.

The trend in the treatment of bone and soft tissue sarcomas of the extremities has been away from radical surgery and toward conservative, limb-sparing surgery, a trend that is present throughout other subdisciplines of surgical oncology. Organ-sparing and limb-sparing surgery has been combined with the use of adjuvants to give equivalent local control and in some cases improved survival. This article summarizes the current staging and treatment of bone and soft tissue tumors of the extremities and discusses some of the features that are unique to the elbow and forearm.

Adult↗
PubMed1994

Allograft reconstruction after proximal tibial resection for bone tumors. An analysis of function and outcome comparing allograft and prosthetic reconstructions.

Seventeen patients (age, 12-63 years; median, 22 years) treated with proximal tibial allografts were identified. Nine cases were intercalary and eight were osteoarticular allografts. Complications, number of operations, and oncologic and functional results were reviewed. The functional results of the allografts were compared with a prior cohort of patients who had endoprosthesis at the same institution by the same surgeons. There were 14 malignant tumors, two benign aggressive tumors, and one sclerosing osteomyelitis mimicking osteosarcoma. Twelve of 17 patients had complications, the most common being fracture, deformity, and infection. Six patients required more than one procedure, and three had amputations after allograft reconstruction. The ultimate function was excellent in three patients, good in seven, fair in six, and poor in one. There were 14 patients with endoprosthetic reconstruction. Wound problems followed by prosthetic loosening were the most common complications. Of the eight patients requiring a second procedure, three had an amputation. Three had excellent, seven good, and four fair functional results at the final evaluation. No patient in either group had a local recurrence. Allograft provides an alternative to endoprosthetic reconstruction; however, the high incidence of complications makes the outcome unpredictable. Allograft or prosthetic reconstruction provides better functional results than amputation without sacrificing oncologic results.

Adolescent↗
PubMed1993

Management of extremity soft-tissue sarcomas.

Management of extremity soft-tissue sarcomas requires accurate clinical staging, pathologic diagnosis, surgical resection with a wide margin, and adjuvant radiation therapy for high-grade lesions. Brachytherapy offers a clean benefit in local control for large (> 5 cm) high-grade sarcomas. The role of radiation therapy for small high-grade and all low-grade soft-tissue sarcomas still is being evaluated. Survival is function of histologic grade, age of patient, size and location of the tumor, metastases, and adequacy of the surgical resection. Efficacy of chemotherapy has yet to be proven.

Adolescent↗