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Biomedical subjects

C Franceschi

Publications and source records attributed to C Franceschi.

At least 343 records · Page 19Linked to original sources
PubMed1979

Microplate enzyme-linked immunosorbent assay in the study of the structural relationship between myosin light chains.

A microplate enzyme-linked immunosorbent assay (microELISA) for the study of immunochemical relationships between rabbit myosin light chains is described. Purified individual fast-muscle myosin light chains (LC1F, LC2F and LC3F) and their respective antisera, obtained in chicken, were used. Optimal conditions for antigen concentration, antiserum dilution, substrate concentration, incubation time and reproducibility with time were established. The observed cross-reactivities between the different types of light chains associated with rabbit fast-muscle myosin confirm and extend previous results obtained by other authors using radioimmunoassay procedures. It was concluded that microELIAS may be successfully employed also to the study of macromolecule cross-reactivities.

Animals↗
PubMed1978

[Chronic persistent HBsAG positive hepatitis in children. I. Subpopulations of T and B lymphocytes].

T and B peripheral blood lymphocytes were studied in five children affected by chronic persistent hepatitis HBsAg-positive. The percentage of E rosette forming cells was found decreased while thymidine uptake after Phytohaemagglutinin stimulation reached values higher than that of normal controls. Null cells were found increased. In all the patients the percentage of IgG bearing lymphocytes was markedly decreased. Such alterations of T cells compartement are similar to those found by other authors in the aggressive form. The hypothesis of a derangement of T cell subpopulation regulatory activity is put forward.

B-Lymphocytes↗
PubMed1978

[Chronic persistent HBsAg positive hepatitis in children. II. Effect of treatment with levamisole].

In five children affected by HBsAg positive chronic persistent hepatitis a treatment with Levamisole (LMS) modified several immunological parameters which had been found altered before treatment. In particular the percentage of E rosette forming cells increased while that of EAC decreased; B lymphocytes with SmIgG and the responsiveness to phytohaemagglutinin, which were significantly decreased and increased respectively, got normal values. Since the persistence of HBsAg was unaffected by LMS treatment and a light increase of transaminase serum levels (GPT and GOT) was observed during treatment, doubts are expressed about the opportunity of using LMS in children affected by such a form of hepatitis.

Alanine Transaminase↗
PubMed1977

Compared effects of N-hydroxyurethan, urethan and hydroxyurea on DNA synthesis. In vivo and in vitro studies.

The effect of N-hydroxyurethan (HUR) on DNA synthesis has been tested both in vivo on various tissues and in vitro on concanavalin A (ConA)-stimulated rat thymocytes and compared with the action of urethan and hydroxyurea. HUR suppresses scheduled DNA synthesis, except that of non-stimulated spleen cells in vitro. The inhibition is efficient and rapid and takes place immediately if the drug is administered at the peak of the S-phase. UR inhibits DNA synthesis in vitro only at much higher doses and with different time course. It is effective or slightly effective if it is administered at the peak of the S-phase. A conversion of urethan into HUR the latter depressing DNA synthesis could partly explain the differences observed. No toxicity was found after treatment with drugs at the concentration employed. Finally, the relationships between drug doses and cell responses have been particularly observed in vivo.

Animals↗
PubMed1976

Selective effect on T and B cell subpopulations in rat lymphoid organs after urethan treatment.

In vitro phytohemagglutinin (PHA) and concanavalin A (Con A) responsiveness of thymus and bone marrow cells, and E, EA, and EAC rosette-forming cells (E, EA, EAC) of these organs and spleen were studied in Fisher rats at various time intervals following a carcinogenic treatment with urethan (UR). Immediately after treatment, organ cellularities were drastically reduced with a progressive recovery as time passed. 1 day after treatment, the response of thymocytes to PHA showed a fourfold increase while organ cellularity dropped to 1%. This response fell below normal values after 7 days with an overshoot after days 14 and 21. UR-treated bone marrow cells showed a response to PHA below normal values after 1 and 7 days, a twofold increase after 3 days and an overshoot after 14 and 21 days. The responsiveness to Con A of both organs was affected by UR treatment to a much lesser extent, although following a pattern similar to that of PHA. E were never found, whether in normal nor in UR-treated animals. As far as the B-cell compartment is concerned, UR causes a progressive diminution of EAC, while the number of EA remains unaffected. The data are discussed in terms of selective effect on T- and B-cell subpopulations.

Animals↗
PubMed1972

Maturation of the immkune response in vitro. Focal fluctuation and changes in affinity of anti-beta-D-galactosidase activating antibody.

We have cultivated lymph node microfragments from beta-D-galactosidase (Escherichia coli) primed rabbits and have measured their secondary response directed towards the whole molecule (precipitating antibodies) and to a single determinant (activating antibodies) of the antigen. By decreasing the size of the fragments to 10(5) cells, we began to observe heterogeneity among identical cultures in terms of positivity of response, antibody specificity, and titers. The affinity of "early" activating antibodies was inversely proportional to the dose of challenge. While no maturation was seen in low and excessive challenge, in all cultures receiving intermediate doses the association constant was raised several orders of magnitude within periods of 20 days. The relevance of these data to the mechanism of affinity selection of antigen-sensitive cells is discussed.

Animals↗