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M E Estévez

Publications and source records attributed to M E Estévez.

11 recordsLinked to original sources
PubMed1989

[The monocyte-macrophage system in Hodgkin's disease].

Hodgkin's disease (HD) is considered as a tumor of the lymph nodes histologically characterized by a variety of cell types, resembling a nonspecific inflammatory reaction. The Reed-Sternberg cells present in the granuloma are considered neoplastic due to cytogenetic alterations, tissue culture properties and heterotransplantability. They originate from a macrophage-derived interdigitating reticulum cell. The lymph node is an immunologic organ and its alterations reveal qualitative and/or quantitative defects of the immune system. These are observed in HD at very early stages even with a minimum of lymph node involvement. Considering HD as a neoplasm of the monocyte-macrophage system, our objective was to investigate the functional capability of peripheral blood monocytes transformed into macrophages in vitro. The phagocytic and lytic activities were evaluated by the generation of toxic oxygen metabolites as due to an excessive production of PGE-2. This defect could be corrected by cyclo-oxygenase inhibitors. The defect was present at very early stages of HD and persisted even during prolonged continuous complete remissions. We also found a defect in the ingestion of candida which could not be modified by drug treatment, indicating the existence of a global dysfunction of the phagocyte. Presently, more than 90% of HD patients respond to specific therapy and remain in prolonged remission, being considered "cured". This fact may contribute to the diminished number of reports in relation to the biology of the monocyte-macrophage system in this disease.

Arachidonic Acids↗
PubMed1989

[Immunologic studies in thalassemia major].

It is accepted that the immune alterations in patients with thalassemia major (TM) are secondary to the continuous transfusion-related antigenic stimulation together with iron overload. We evaluated the immune status of TM patients and found quantitative alterations in the distribution of peripheral blood lymphocyte subpopulations as well as functional alterations in natural killer (NK) cytotoxicity, B-cell differentiation, T-cell immunoregulation and phagocyte functional activities. TM patients, 10 years old or younger, have a lymphocyte profile and phagocytic activity similar to normal controls. Non-splenectomized thalassemic patients, older than 10, present lymphocytosis due to an increase in B lymphocytes and with splenectomy the T-CD8+ lymphocytes increase. With respect to phagocytes, the capacity to ingest candida is preserved while the candidacidal activity and the generation of toxic oxygen metabolites during the respiratory burst are diminished, and are inversely proportional with age and serum ferritin concentration, that is, older in age and higher in iron overload, more profound are the phagocyte dysfunctions. The altered B-cell function, the dysfunction of T immunoregulatory cells and the defective NK activity observed in TM patients were independent of the age of the patients and they were observed even in children younger than 10 years old and in general are attributed to blood transfusions. Moreover, there are some alterations that thalassemic carriers can express such as a defect at the level of NK and at B-cell function regulations, suggesting a possible genetic origin. Although complex, TM constitutes a human model that allows the dissection of specific immune defects, involving multiple factors, and can provide a better comprehension of how this complex immunoregulatory system works.

Humans↗
PubMed1984

[Visualization of specific leukocyte granules using morin and other fluorochromes].

The visualization of the specific granulation of leukocytes is useful in hematology to identify de cell type in leukemic diseases. The authors employed the acidic fluorochrome morin after testing its high affinity for the fluorescent reaction with morin in human and chicken peripheral blood smears, and in streak smears from rabbit spleen. The best results were obtained with a solution prepared either with 0.10 mg morin per ml of 50 per 100 ethanol, or with a saturated solution of morin in distilled water diluted to one fourth in 25 per 100 ethanol. When observed under blue-violet excited light (436 nm) the acidophilic granules of leukocytes produce a bright yellow fluorescence, while the cell nuclei show a faint greenish fluorescence. As for the mechanism of the reaction, it consists possibly in an interaction between morin and the basic components of the granules. Other acidic fluorochromes, as primulin and hematoxylin, produce similar fluorescent reactions with the acidophilic granules.

Animals↗
PubMedDate not supplied

Chemotactic function of polymorphonuclear leukocytes from patients with recurrent infections: partial correction by levamisole "in vitro".

Polymorphonuclear leukocytes are dominant cells in the defense of the organism, and their functional alterations result in increased risks of infection. Chemotaxis is an early function in the immune response, allowing for the polymorphonuclear cells to migrate towards inflammatory sites. We studied the chemotactic function of the polymorphonuclear leukocytes from 14 patients with the common clinical syndrome of recurrent infections, through a technique of cell migration under agarose. It was found to be depressed in 5 patients, in the lower limit of normal in 2 cases, normal in 6 cases and enhanced in 1 patient. The "in vitro" incubation of polymorphonuclear cells with 5 mM levamisole resulted in a partial correction of their chemotactic function. Our results indicate that the chemotactic function of neutrophils should be evaluated in patients with recurrent infections, for the better understanding of the underlying dysfunctions in these diseases.

Adolescent↗