Biomedical subjects

E Leonardo

Publications and source records attributed to E Leonardo.

58 records · Page 4Linked to original sources

PubMedDate not supplied

The thousand and one ways of being a T cell.

Developing T cells diverge to several different effector classes, identified by their ability to express different set of genes. Aside from the genes encoding components of the TCR/CD3, there are many others that are activated and/or inactivated during T-cell development, but the functions of most of them are not yet defined. Despite the significant progress made, several fundamental aspects of the major steps of T-cell differentiation remains unclear. Thus, while long ago it was realized that the thymus is a central organ for the development of functionally competent T lymphocytes, it appears clear today that ectopic T-cell differentiation can also take place. In this article we review some of the molecules implicated in T-cell development and discuss some of the pathways that lead to mature T cells from precursors, both intra- and extra-thymically, as well as their implications in the acquisition of self tolerance.

Cell Differentiation↗

PubMedDate not supplied

[Immunological changes in diabetes mellitus. Study of lymphocyte populations].

In view of some data of the literature suggesting that immunological changes could play a role in the pathogensis of diabetes mellitus and of its complications, we carried out a study of the lymphocyte populations of 44 diabetic subjects by means of E, EA, EAC rosettes and membrane immunofluorescence. A quarter of the patients had decreased E rosettes: all of these had long-lasting, insulin-dependent, poorly controlled diabetes. Some of these patients had also increased membrane IgG globulins. In 5 patients with recent onset, insulin-independent diabetes, E rosettes were increased. No significant changes of EA and EAC rosettes were observed. These findings suggest that changes of lymphocyte populations do not play any role in the pathogenesis of diabetes, while these may be the consequence of the metabolic disorder and these may favour the onset of complications of the disease.

Adult↗

PubMedDate not supplied

[Immunopathological characteristics of the lymphocytes of chronic lymphocytic leukemia, fractionated on gradients of various densities].

Spontaneous rosettes and membrane immunofluorescence for the various classes of heavy and light immune globulin have been determined on lymphocyte subfractions obtained from the blood of 6 normal subjects and 16 patients with CLL by separation on gradients of various density. Whereas in the normal subject lymphocyte immunological features proved similar in all fractions, in CLL they presented significant differences from fraction to fraction, with the presence only in certain fractions of the lymphocyte peak with monoclonal membrane immune globulin and without peak coincidence for IgD and IgM, probably as a result of changes in the physico-chemical features of the lymphocytes occurring during maturation. All fractions presented a sizeable complement of lymphocytes not forming rosettes and without demonstrable membrane immune globulins. The correlation between the behaviour of membrane labels and lymphocyte morphology, stage, duration and course of the disease has been analysed. The variability in lymphocyte subfraction characteristics separable at different densities may explain discrepancies of findings in researches carried out in lymphocytes that separate only at gradient of density 1077.

Aged↗

PubMedDate not supplied

High frequency of p53 expression in colo-rectal adenomatous polyps.

Previous studies on p53 protein expression in colonic adenomas showed controversial results. The present study evaluates the p53 expression in colonic adenomas, at different dysplasia degrees, by immunohistochemical analysis, using a newly introduced monoclonal anti-p53 antibody. Paraffin embedded sections of 48 colorectal adenomas, 5 colonic carcinomas and 11 normal colonic biopsies were studied by immunohistochemical analysis using a monoclonal mouse anti-p53 antibody (clone DO-1). Normal colonic mucosa specimens and 5/48 adenomas were found negative for p53 staining. p53-positive nuclei were less than 10% in 22/48 and between 10 and 40% in 15/48 adenomas. In 6/48 adenomas and in 4/5 carcinomas we found a high percentage of p53-positive nuclei (> 40%). Immunohistochemical p53-positivity is a common event in colonic adenomas, not dependent on dysplasia degree. It might be the result of p53 wild-type increase, due to the typical genomic instability of colonic adenomas.

Adenomatous Polyps↗