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Biomedical subjects

J Costa

Publications and source records attributed to J Costa.

At least 289 records · Page 16Linked to original sources
PubMed1979

Spike separation in multiunit records: a multivariate analysis of spike descriptive parameters.

Variables describing unit discharges from multiunit extracellular records were treated, using multivariate statistical analysis for further automatic spike separation. A spike was described by 8 parameters (3 amplitude values, 3 time values and 2 slopes). These 8 parameters were summarized by 2 new independent factors, the principal components (PC). Examination of the 2 PCs from each spike allowed the observer to determine PC families corresponding to spike populations. From these the spikes were automatically classified. PC analysis showed groups of redundant parameters. Elimination of redundancy decreased the computing time without lowering the separation efficiency of the method. Three parameters turned out to be sufficient for spike discrimination: the maximum and the minimum amplitudes and the time between these. This agrees well with the physical basis of current propagation in the conducting medium, from the firing neurone to the recording electrode.

Action Potentials↗
PubMed1979

Histologic grade in advanced ovarian cancer.

The histologic grade of epithelial ovarian tumors was found to be a major prognostic factor for survival in patients with advanced (stage III-IV) disease. In addition, a grading system based on cytologic detail (modified Broders' grades I-IV) identified groups with a differential response to chemotherapy. The overall improvement in survival observed with combination chemotherapy was related primarily to an increased survival of patients with grade II and III lesions. Although the survival of patients with grade I lesions was markedly better than for patients with grade IV lesions, in neither case was it influenced by the choice of single-agent or combination chemotherapy. In prospective clinical trials in advanced disease, modified Broders' grades should be included as a separate stratification factor.

Altretamine↗
PubMed1979

Treatment of osteogenic sarcoma. I. Effect of adjuvant high-dose methotrexate after amputation.

Thirty-nine patients with extremity osteogenic sarcoma and no discernible metastases were treated with amputation and postoperative adjuvant high-dose methotrexate with leucovorin rescue. One half of the patients were also randomized to receive bacillus Calmette-Guérin by a multiple-puncture technique. Results have been analyzed with a minimum followup of 10 months and a median followup of 27 months. Actuarial analysis estimates that 38% of current protocol patients remain continuously free of disease for 24 months compared to only 17.4% of historical control patients (P = 0.029; one-sided generalized Kruskal-Wallis test). Bacillus Calmette-Guérin administered by a multiple-puncture technique had no effect on disease-free interval. Minor differences between current protocol and historical control patients with regard to race, age, histologic type, and site and size of primary tumors do not affect the difference in disease-free interval between these two patient groups. However, current patients had somewhat lower grade lesions and consideration of the patients with grade III and IV lesions only, lessens the difference between current and historical control patients (P = 0.11; one-sided generalized Kruskal-Wallis test). High-dose methotrexate was administered with virtually no morbidity and no deaths. The small differences observed in this study between protocol patients treated with surgery plus high-dose methotrexate and historical control patients treated with surgery alone point to the need for a prospective randomized study to establish the role of high-dose methotrexate in the adjuvant treatment of patients with osteogenic sarcoma.

Adolescent↗
PubMed1978

Osteosarcoma associated with Thorotrast administration: report of two cases and literature review.

Two cases of osteosarcoma are described arising in patients who had undergone angiography with Thorotrast during childhood. In both patients, there was radiographic and pathologic evidence of radioactive thorium dioxide deposition in bone as well as throughout the reticuloendothelial system. Thorotrast deposits were demonstrated in the immediate vicinity of the primary tumors by both histology and autoradiography. Previous cases of osteosarcoma associated with Thorotrast administration from the literature are cited, and possible causal relationships are discussed between thorium retention in bone and neoplastic transformation by chronic radiation.

Adolescent↗
PubMed1978

Characteristics of the Fc receptor induced by herpes simplex virus.

Studies of the Fc receptor induced by herpes simplex virus using the 7S EA rosette assay reveal that (i) the percentage of cells showing receptor activity is multiplicity-dependent; (ii) the percentage of cells rosetting is independent is independent of the cell cycle phase of the host cell; (iii) RNA and viral protein synthesis, and probably glycosidation, are required for the induction of the receptor but not viral DNA synthesis; and (iv) the receptor is neuraminidase-resistant but trypsin-sensitive.

Binding Sites, Antibody↗
PubMed1978

Increased risk of lymphoma in sicca syndrome.

The risk of cancer was ascertained in 136 women with sicca syndrome followed at the National Institutes of Health (NIH). Seven patients developed non-Hodgkin's lymphoma from 6 months to 13 years after their first admission to NIH. This was 43.8 times (P less than 0.01) the incidence expected from the rates of cancer prevailing among women of the same age range in the general population during this time. In addition, three cases of Waldenström's macroglobulinemia occurred in this study group. Eight patients developed cancers other than lymphoma, similar to the number expected based on the rates prevailing in the general population. Patients with a history of parotid enlargement, splenomegaly, and lymphadenopahy had an increased risk of lymphoma. These clinical conditions did not appear to be early manifestations of undiagnosed lymphoma but rather seemed to identify a subgroup of patients with sicca syndrome with marked lymphoid reactivity, who had a particularly high risk of subsequently developing lymphoma.

Adult↗
PubMed1978

Properties of the cell surface Fc-receptor induced by herpes simplex virus.

Detection of peroxidase-antiperoxidase soluble complexes (PAP) bound to the surface of herpes simplex virus-infected cells has been used to demonstrate virus-induced Fc receptors and to study their distribution. The PAP method is more sensitive than hemadsorption with immunoglobulin-coated sheep red blood cells, and can be used to study localization by light and electron microscopy. Our results indicate that capping takes place after the receptor is engaged by antigen-antibody complexes and that at least a portion of the bound ligand is internalized.

Animals↗
PubMed1977

Hexamethylene bisacetamide induces morphologic changes and increased synthesis of procollagen in cell line from glioblastoma multiforme.

Addition to hexamethylene bisacetamide (diacetyldiaminohexane) to cultures of a malignant mesenchymal cell line derived from a human glioblastoma multiforme induces morphological changes and stimulates the synthesis of procollagen. The morphological changes include cell elongation, an increase of extracellular material with staining properties of collagen by light microscopy, and an increase in extracellular 220-A fibrils by electron microscopy. The rate of procollagen synthesis increased as much as 20-fold, and the ratio of type I:type III procollagen changed, with type I becoming the predominant form. The change in type I:type III ratio is similar to that seen in the maturation of normal fetal to adult connective tissue.

Acetamides↗
PubMed1977

Oncogenicity of a nude mouse cell line transformed by a human papovavirus.

Primary cultures of NIH nude mouse (nu/nu) kidney cells were transformed with a human papovavirus (MMV). The transformed cell line expressed T-antigen, and MMV DNA was found to be associated with the cell DNA. When NIH nu/nu mice were inoculated with the transformed cells, they developed tumors at the injection site but failed to generate detectable levels of T-antibody. A control group of nu/+ littermates rejected the tumor inoculum but mounted an antibody response to T-antigen. It was proposed that nude mouse cells may be a suitable system to test oncogenicity of in vitro transformed cells.

Animals↗
PubMed1977

Spontaneous lymphosarcoma arising in a nude mouse: characterization in vivo and in vitro.

A lymphosarcoma spontaneously arising in a nude mouse and a continuous cell line (NML-1) derived from it are described and compared. The primary tumor and a transplantable tumor line from it were composed of lymphoid cells, with no C-type viral particles seen by electron microscopy. The culture line was composed of cells with morphologic and functional properties of macrophages; budding C-type particles were abundant. The cells in the tumors produced in nude mice by injection of the NML-1 cells also resembled macrophages morphologically rather than lymphocytes; however, by electron microscopy, no C-type particles were seen. The findings suggest some type of in vivo suppression of complete expression of the virus.

Animals↗
PubMed1977

Prognostic factors in patients undergoing lymphadenectomy for malignant melanoma.

Review of a 19 year experience in melanoma patients undergoinglymphadenectomy at the National Cancer Institute revealedthat the preoperative assessment of the status of theregional lymph nodes was accurate 91% of the time when thesurgeon felt the nodes were clinically positive, and accurate79% of the time when the nodes were judged clinically negative. The 10-year survival in patients with one to three histologicallypositive nodes or no positive nodes was 50-55%, compared to a25% 8-year survival in patients with four or more histologicallypositive nodes. Stepwise multivariate evaluation of prognosticfactors indicated that the most important factor for predictingprognosis is the number of nodes histologically involved. Nodepalpability was the second most important factor because of itshigh correlation with number of nodes histologically involved. Site of melanoma was the third most important factor, aspatients with extremity (upper or lower) melanoma had a bettersurvival (P = 0.002) than patients with axial melanoma (trunkor head and neck). Five years following lymphadenectomythere appeared to be substantial differences in survivalaccording to differences in the level of invasion of the primarylesion, however, these differences were not nearly aspronounced 10 years following node dissection.B The division of melanoma thicknesses into <1.50 mm and>1.50 mm provided some prognostic discrimination at fiveyears but again the differences were not pronounced 10 yearsfollowing node dissection. The thickness measurements wereeasier to determine than the level of invasion, and more reproduceableon resubmission to the same pathologist. Fourpatients with melanoma less than 0.76 mm had subsequentmetastases, but these may represent inadequate sampling of theprimary melanoma both in our series and in the four similarpatients previously reported with such thin metastasizingmelanomas.

Female↗