No abstract

The prognosis in cases of nonmetastatic Ewing's sarcoma is influenced by many different clinical and hematologic variables, all of which are to be considered when patients are being stratified according to the risk of relapse. In surgically treated patients, the most important prognostic factor is chemotherapy-induced necrosis.

The proposed histopathologic grading, to evaluate the effect of chemotherapy on the primary tumor, had the strongest correlation to clinical outcome. This method could therefore be used to identify patients with a high risk of recurrent disease. These patients could be randomized to receive alternative postoperative treatments to investigate whether more aggressive therapies will improve outcome.

No abstract

The results of our study confirm that the prognosis of patients with osteosarcoma of the extremity, metastatic at presentation, remains poor, despite the use of aggressive treatments.

Studies on the curing reactions of epoxy systems were carried out in the presence of a cellulose derivative, hydroxypropyl cellulose (HPC). The technique of differential scanning calorimetry (DSC) was applied to characterize the curing reactions/thermal properties. Classical nonisothermal kinetic methods, such as the Kissinger and the Osawa methods (multiple scan) and the Barrett method (single scan) as well as the recently one proposed by Samios et al., were applied to study the reaction kinetics of the epoxy system of diglycidyl ether of bisphenol A (DGEBA) and 4,4′‐diaminodiphenylmethane (DDM) with HPC. The Barrett method gives additional information about the process of initiation, gelation, and vitrification. At the beginning of the epoxy curing reaction, HPC acts as a catalyst so that the energy of activation diminishes and the reaction occurs at lower temperatures. Above the minimum temperature Tmin, it was concluded that HPC behaves as an inhibitor of the reaction (Tmin is the temperature which corresponds to the minimum point showed by the exotermic peaks during the curing reaction of an epoxy resin measured by DSC). By analyzing the behavior of the kinetic parameters, Ea, k, and ln A, the molecular interactions were shown to be related to the catalyst–inhibitor characteristics of HPC. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 676–683, 2003

No abstract

Background. A clinicopathologic study of 70 cases of cellular schwannoma was performed to assess their distribution, response to therapy, and rate of recurrence relative to modern prognostic indicators. Methods. Seventy‐one cellular schwannomas from 70 patients were retrieved from the files of the Mayo Clinic Tissue Registry. The significance of mitotic index, proliferative marker staining (proliferating cell nuclear antigen and MIB1), immunochemical p53 expression, and DNA ploidy were assessed relative to tumor behavior, particularly recurrence. All parameters were subject to statistical analysis (Student's t test). Results. Cellular schwannomas represented 4.6% of benign peripheral nerve tumors operated on at the Mayo Clinic. In 15% of the cases, an initial diagnosis of malignancy had been made. The median patient age was 47.7 years (range, 15‐80 years) and the female‐to‐male ratio was 1.6:1. The principle tumor locations were the para‐and intraspinal regions, including the sacrum (64%), extremities (25%), and intracranial space (8%). All tumors consisted primarily of hypercellular, compact, Antoni A tissue. Mitoses (⩽4/10 hPF) were observed in 71% of the cases. Foci of necrosis were noted in 11% of cases. Ultra‐structural studies and immunohistochemistry clearly demonstrated features of schwannian differentiation. Surgery was the treatment in all cases. Excision was intralesional to gross total in the majority; total resection with wide margins was undertaken in three tumors, each of which had initially been considered malignant. Follow‐up in 47 patients (67%) ranged from 1 to 29 years (mean, 7.7 years) and revealed recurrences in 11 patients (23.4%): no patient experienced metastasis or died of tumor. Although no correlation existed between recurrence and DNA ploidy, percent S‐phase determinations, proliferation marker (PCNA, MIB1) staining, or the frequency of p53 immunoreactivity, a statistically significant correlation (P < 0.001) was observed, however, between recurrence and mitotic indices. Conclusion. Proliferation indices, as defined by immunochemical analysis, are not useful predictors of recurrence in cellular schwannoma. In lesions not completely resected, tumor recurrence is significantly correlated with mitotic count. The significant overall frequency of recurrence in this series is attributable to a high proportion of intraspinal and intracranial tumors. Our study confirms the benign nature of cellular schwannoma and underscores the necessity of distinguishing them from malignant peripheral nerve sheath tumors, lesions that often require adjuvant therapy. Cancer 1995;75:1109–19.