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R Arnould

Publications and source records attributed to R Arnould.

24 records · Page 2Linked to original sources
PubMedDate not supplied

[Adjustment of the dose-effect curve by means of an original algorithm. Application to the study of cytotoxicity in vitro].

Dose-effect curves were fitted in optimizing a non-linear cost function by the simplex method. Two kinds of mathematical functions (Gompertz and Von Bertalanffy) and some weighting processes were studied. In each case a statistical analysis was carried out to choose the curve which is best fitted to experimental data. From the best curve, the efficient doses were calculated. This work was illustrated by cytotoxicity studies concerning melphalan and pyrrolidin.

Algorithms↗
PubMedDate not supplied

Production of interleukin 1 by activated blood monocytes and alveolar macrophages from melanoma patients.

The production of Interleukin 1 (Il1) by circulating blood monocytes and alveolar macrophages was studied in melanoma patients. There were 144 patients in the monocytes study and 5 patients in the alveolar macrophages study. The Il1 activity was tested by a bioassay and reported in units based on the integration of the area under the curve. This was shown to be preferable to the standard method, i.e. probit analysis. Results showed that there was no depression of Il1 activity in melanoma patients as compared to control (98 + 32 units, versus 100 units). There was no difference when the values were compared according to sex, age and stage of the disease. However, a significant difference was found between phototype I and phototype IV. Alveolar macrophages, in all experiments (n = 5), had a significantly lower Il1 activity than the autologous monocytes. It is concluded that we can question the relevance of Il1 production by peripheral blood monocytes to the state of the immunity of melanoma patients.

Adult↗
PubMedDate not supplied

A new test for phagocytosis of human alveolar macrophages in suspension, using 99mTc labelled human serum albumin particles.

Current studies on human alveolar macrophages (HAM phi) indicate that two subpopulations may exist: adherent and nonadherent HAM phi. Most works in the literature were done exclusively on adherent HAM phi. In order to obviate to the loss of nonadherent HAM phi, we elaborated a new test for measuring endocytosis in HAM phi suspensions. According to this method, HAM phi in suspension were allowed to phagocytize millimicrospheres of human serum albumin labelled with 99m Tc (0.2 less than 0 less than 0.5 m; TcK9R - Cis Sorin Biomedica). Bound activity was separated from free activity by centrifugation on PercollR. The resulting internatant ring was found to contain activity bound to HAM phi which had phagocytized human serum albumin millimicrospheres. HAM phi were characterized by morphology and cytochemistry. The method here presented allows the functional study of both adherent and non-adherent HAM phi populations.

Humans↗
PubMedDate not supplied

Monoclonal antibodies to human melanoma associated antigens: study of their specificity and visualization at the cellular level of the antigenic distribution.

Six monoclonal antibodies(Mabs) including 4 anti-melanoma, one anti-glioma, and one anti-HLA-DR have been tested in a 125I-protein A antibody binding assay using a panel of 34 different cell lines. This panel included 19 melanomas from different clinical and geographical origins, 10 fibroblast lines out of which 9 were established from melanoma patients, 2 glial cell lines, 1 osteosarcoma, 1 teratocarcinoma, and 1 murine melanoma. The reactivity pattern of the 4 anti-melanoma Mabs showed that they were not directed against antigens strictly restricted to melanoma, but rather against antigenic structures preferentially expressed on melanoma cells. These Mabs were found to crossreact with gliomas, thus they seem to recognize neuroectoderm associated differentiation antigens. The high crossreactivity of the anti-glioma Mab for melanoma was confirmed in this study. As expected from the literature, HLA-DR antigens were found to be expressed on more than 50% of the melanoma lines tested. The cellular distribution of the antigens recognized by two anti-melanoma Mabs on melanoma cells could be visualized by an autoradiographic procedure. From the labeling pattern it was concluded that only a proportion of the cells, varying from 13 to 38%, expressed the relevant antigen.

Antibodies, Monoclonal↗
PubMedDate not supplied

Effects of 5-fluorouracil on various melanoma cell metabolisms. Its use for assessing the cold thymidine pool.

5-Fluorouracil (5FU) increases the rate of incorporation of tritiated thymidine (3HTdR) and iododeoxyuridine (125 IUdR) into the cell and its DNA. 5FU has differential effect on metabolism of DNA through its specific action on thymidylate synthetase. Effects of 5FU on the incorporation of other metabolic precursors were studied, as well as the sensitivity of different cells to 5FU. This multiparametric approach enables us to predict the effect of 5FU on a cell type depending on its cold thymidine (TdR) pool size and the permeation of the cell to the drug. Furthermore, 5FU was used as a tool to recognize the difference between the effects of TdR on the 3HTdR and 125IUdR incorporation. Three parameters are superimposed: isotope dilution, inhibition of metabolic activity of the pyrimidine synthesis and metabolic competition between TdR and UdR. The measurement of the TdR pool size of the cell can be obtained using a specific equation, which is a function of the slope of the inhibition curve of the labelled precursors (3HTdR and 125IUdR) incorporation.

Animals↗