Biomedical subjects

E Moretti

Publications and source records attributed to E Moretti.

At least 55 records · Page 3Linked to original sources

PubMed1993

Comparative experimental study of autologous adipose tissue processed by different techniques.

Different techniques for processing adipose tissue were tested in 40 Swiss Albino female mice. Our study established that the use of insulin did not show any positive effect on survival of adipocytes during their transplantation. Likewise, the use of a centrifuge machine, at high or low speed, for separating the adipose tissue components, completely destroyed the adipose cells and did not allow their survival.

Adipose Tissue↗

PubMed1993

Evaluation of the antifertility activity of the broom Spartium junceum in the mammalian male.

Male adult rabbits and rats treated with Spartium junceum showed a significant decrease in fertility, demonstrated by a lower number of pregnancies. The target of the drug seems to be the acrosomal protease system, the activity of which appears greatly reduced, while the morphology of testicular cells and epididymal spermatozoa is only partially affected. The antifertility effect is completely reversible.

Acrosome↗

PubMed1993

Molecular basis of Trypanosoma cruzi-induced immunosuppression. Altered expression by activated human lymphocytes of molecules which regulate antigen recognition and progression through the cell cycle.

The mechanisms by which Trypanosoma cruzi causes dysfunction in normal human lymphocytes was studied by using an in vitro system in which purified parasites and normal peripheral blood mononuclear cells are co-cultured in the presence or absence of mitogens. Our results have shown that T. cruzi impairs the expression of receptors for interleukin-2 (IL-2R) and transferrin, activated lymphocyte membrane molecules which play key roles in controlling progression through the cell cycle. T. cruzi also downregulates the expression of constitutive lymphocyte molecules (e.g., CD4, and CD8) involved in the interactions between antigen-presenting cells and T lymphocytes as well as the expression of T cell receptor (TCR) and CD3 molecules. The latter molecular structures are physically associated and are responsible for signaling and transducing activation events resulting from antigen binding. Stimulated B lymphocytes also display reduced IL-2R expression in the presence of T. cruzi. In contrast, neither the expression of EA-1 molecules by T lymphocytes nor that of CD19 and CD20 molecules by B lymphocytes is affected by this parasite. Thus, the T. cruzi effects are selective, not indiscriminate. The activated T cell populations affected by T. cruzi show concomitant reductions in the levels of expression of IL-2R and CD4, IL-2R and CD8, IL-2R and CD3 or IL-2R and TCR as well as in their capacity to proliferate; 3H-thymidine uptake decreases and there is a massive arrest of cells at the G0/G1a phase of the cell cycle. The immunosuppressive effects of T. cruzi are reproduced by a protein molecule(s) released spontaneously by the parasite termed TIF (for trypanosomal immunosuppressive factor). We report herein that TIF does not compete with IL-2 for binding to IL-2R and that shedding of IL-2R is decreased in the presence of T. cruzi. Moreover, the intracellular level of IL-2R was found to be lower than that found in control cells cultured in the absence of parasites. These results suggest that suppressed IL-2R reflects a modification induced by T. cruzi at a time coinciding with or preceding IL-2R mRNA translation. Studies are underway to identify the earliest process targeted by T. cruzi.

Animals↗

PubMed1993

Studies on varicocele. II. The inhibin secretion.

In this paper a previous interpretation given by the authors concerning one of the ways varicocele can affect fertility is confirmed. Moreover, it is definitely demonstrated that the high temperature stimulates inhibin secretion (and probably the testosterone-estradiol conversion) in the Sertoli cells, while the somatomedin secretion in vitro seems to be unaffected. It means that the action of the temperature on the germinal cells seems to be mediated by the pathway: inhibin (plus estradiol)-->pituitary-->FSH. Inhibin in the Golgi complex of Sertoli and germinal cells has been detected by electron microscopical immunocytochemical techniques.

Adult↗

PubMed1991

Trypanosoma cruzi induces suppression of DNA synthesis and inhibits expression of interleukin-2 receptors by stimulated human B lymphocytes.

Trypanosoma cruzi, the causative agent of Chagas' disease, suppresses immune responses during the acute phase and has been shown to induce multiple cellular alterations in activated human T lymphocytes. However, no information is available regarding the effects of this parasite on human B cells. Using an in vitro culture system, in which purified T. cruzi are co-cultured with either peripheral blood mononuclear cells (PBMC) or B-cell-enriched preparations (BCE), we studied whether the organism can induce alterations in DNA synthesis after stimulation with Pansorbin (PS). This response was markedly reduced by the parasite at both suboptimal and optimal PS concentrations, and the extent of the inhibition was augmented as the parasite concentration was increased. Maximal reduction in DNA synthesis was observed when the trypanosomes were incorporated into the cultures at 0 time (i.e. together with PS); the effect was of a much lesser magnitude and undetectable when the parasites were added at 24 and 48 hr, respectively. These results imply that T. cruzi affects a relatively early event during B-cell stimulation. This inference was confirmed by the finding that the proportion of PS-stimulated B cells expressing interleukin-2 (IL-2) receptors was significantly reduced when the parasite was present in the culture. Addition of recombinant human IL-2 did not restore B-cell responsiveness to normal levels. Suppressed B-cell responses were also observed when T. cruzi was separated from the PBMC or the BCE by a cell-impermeable filter, indicating that a soluble factor(s) released by the organism mediated the effect. Accordingly, supernatants of T. cruzi suspensions were found to be suppressive. These results demonstrate for the first time that T. cruzi can affect human B-cell responses and that the mechanism involves inhibition of IL-2 receptor expression.

Animals↗

PubMed1989

[Neonatal Chagas disease: laboratory diagnosis during the first year of life].

This paper describes the parasitologic and serologic studies carried out during the first year of life in 721 pediatric patients born to mothers serologically positive for Chagas disease. The search for circulating trypomastigotes was performed by Strout, blood culture and/or Xenodiagnosis. In some cases, amastigotes were also detected in placenta and umbilical cord. Complement fixation test, indirect hemagglutination and indirect immunofluorescence were used to detect Trypanosoma cruzi antibodies. The dosage of total Ig by single radial immunodiffusion was also carried out. The results obtained showed an absolute correlation between parasite detection and the persistence of antibodies after six months of life. In the first group (GI) formed by 8 children, the diagnosis of congenital infection could not be confirmed because the isolation of T. cruzi was obtained only in later studies. In another 8 children grouped in GIII, it was impossible to detect parasitemia, and the diagnosis was reached by the serological positivity after six months of life. Finally, in 684 patients with anti-T. cruzi antibodies at birth, the serology became negative at the age of 3 months (GIV) or 6 months (GV). The methodology employed in this work is accessible to laboratories of medium complexity, and permits the diagnosis of congenital or neonatal chagasic infection with a high degree of reliability. On the other hand, it avoids unnecessary administration of trypanomicide drugs in a number of newborn and infants who have only received maternal antibodies at birth and were not infected by T. cruzi.

Animals↗

PubMed1985