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Biomedical subjects

R Rojas

Publications and source records attributed to R Rojas.

At least 73 records · Page 4Linked to original sources
PubMed1985

Release of granulocyte-macrophage colony-inhibiting activity by normal human postthymic precursor cells.

Seven normal human peripheral blood cell fractions (buffy coat, mononuclear cells, non-T, T, Fc-IgM receptor-depleted T-lymphocyte, Fc-IgG receptor-depleted T-lymphocyte, and autologous rosette-forming T-cell-depleted T-lymphocyte subpopulations) treated with phytohemagglutinin (PHA) were examined for the production of granulocyte-macrophage colony-stimulating activity (CSA). It was found that medium conditioned by a T-lymphocyte subpopulation depleted of autologous rosette-forming T-cells (Tar cells, a postthymic precursor subpopulation that inhibits Ig synthesis) stimulated colony-forming units of granulocyte and macrophages (CFU-GM) to a greater extent than did the other conditioned media (CM) analyzed. Based on this finding, CM from an enriched Tar subpopulation was prepared and thus showed that PHA-treated Tar cells release a factor capable of inhibiting CFU-GM growth. The inhibitory activity of this factor persisted-after heat inactivation, suggesting that cause of the colony-inhibiting activity (CIA) is other than interferon. Further studies revealed that Tar-derived inhibitory factor acts either directly upon CFU-GM or via monocytes/macrophages (M phi/Ma), enhancing CIA, and not the level of CSA production by M phi/Ma. The overall data are interpreted as demonstrating the presence of CIA in a specific T-lymphocyte subpopulation that may represent a new relationship between lymphocytic and myelocytic systems in the human.

Colony-Forming Units Assay↗
PubMed1984

Bifonazole cream in the treatment of superficial candidosis. A double-blind comparative study.

This is the summary of a prospective, randomized, double-blind study comparing four therapeutic regimens: bifonazole cream applied once or twice daily, clotrimazole and placebo twice daily during 4 weeks for the treatment of cutaneous candidosis. The study is multicentric and was accomplished in four centres of different climate: Costa Rica, Dominican Republic, Sweden and Yugoslavia. The trial was carried out with approximately identical numbers of patients: 275 in total. The duration of treatment was 4 weeks and the check-ups were done before, during and 2 weeks after the end of the therapy. The results have shown the great efficacy of bifonazole cream (65-75%) in comparison to placebo (19.4%). There was no significant difference in applying bifonazole cream once or twice daily. So the reasonable therapy with bifonazole as to apply it only once a day, is confirmed. The excellent tolerance and absence of side-effects in such an extended study have once more proved the value of this antimycotic in topical treatment of cutaneous candidosis.

Adolescent↗
PubMed1984

Effect of phorbol ester TPA on macrophage metabolic activity.

Metabolically active macrophages are known to play a role in tumor immune surveillance, not only as effector cells but also as collaborators in T cell mediated immune response. The present work reports that non-toxic concentrations of the tumor promoter TPA, stimulate the adherence of murine peritoneal macrophages after short time incubation, while TPA pretreatment for periods longer than 4 hrs suppresses phagocytosis, RNA and protein synthesis by these cells. Although inhibition of macrophage metabolic activity could play an additional role in tumor promotion, the enhancing and depressing effects of TPA on the immune system must be weighed before it can be assumed that TPA acts in vivo primarily to depress the immune system.

Animals↗
PubMed1984

Depressed lymphoproliferative response in mixed leukocyte reaction after Mis-locus alloimmunization.

The proliferation of BALB/C lymphocytes preimmunized with Mis or H-2 incompatible cells in response to alloantigens was studied. The results show that preimmunization with Mis-incompatible spleen cells inhibits the lymphoproliferative response against alloantigens whereas preimmunization with H-2 incompatible spleen cells enhances it. It is suggested that Mis coded determinants activate suppressor mechanisms responsible for the unresponsiveness of these preimmunized lymphocytes against alloantigens.

Animals↗