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Biomedical subjects

B Esparza

Publications and source records attributed to B Esparza.

25 records · Page 2Linked to original sources
PubMed1986

Antibodies to acquired immune deficiency syndrome (AIDS)-associated virus (HTLV-III/LAV) in Venezuelan populations.

Serum samples from 850 individuals from Venezuela were tested for the presence of antibodies to HTLV-III/LAV virus, the probable etiological agent of acquired immune deficiency syndrome (AIDS). At the time of the study, none of the individuals tested had symptoms indicative of AIDS or related disorders. Viral antibodies were assayed by indirect immunofluorescence (IF) assay, using a chronically infected, HTLV-III/LAV producer cell line CEM/LAV-NIT established in our laboratory. Twenty individuals (2.5%), 8 of them (40%) female, were seropositive by IF and by confirmatory Western blotting and radioimmunoprecipitation assays. The seropositivity rate ranged from 2.4% (11 of 465) in the general healthy population, 4% (2 of 50) among patients with Chagas' disease, and up to 29.2% (7 of 24) among patients with acute malaria infection. The titers of HTLV-III/LAV antibodies ranged from 1:40 to 1:640. In addition, 2 of 36 patients with hemophilia A (5.5%) also had antibodies to HTLV-III/LAV. Two of 7 patients with acute malaria had specific antibodies both to HTLV-III/LAV and HTLV-I, as determined by IF and Western blotting. None of over 169 randomly chosen, healthy blood donors from seven major Venezuelan cities, as well as none of 99 patients with leukemia/lymphoma, had antibodies to HTLV-III/LAV. The presence of specific antibodies among various Venezuelan populations indicates that HTLV-III/LAV, or a closely related cross-reactive virus, is indigenous in Latin American subjects as was previously indicated for tropical populations of central Africa. Isolation and characterization of this virus will help to understand the origin and etiology of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1984

[Gradually diminishing tumor protection caused by reimplants].

Mice from which a MCA-induced sarcoma has been removed and which are exposed to repeated (every three months) tumoral cell transplants, gradually lose their protection against a certain threshold number of cells. Although the survival period after each transplant is longer than in non-protected animals (those that never received a primary tumor) it is seen that while some of them survive for three months (these are the ones to be re-inoculated with tumoral cells) others die. The proportion of mice which die rises with the number of inoculations received; and among those which die, the proportion of mice without localized tumor or neoplastic dissemination is also progressively higher. We do not know why these mice die at a later and cachectic stage without tumor but in a situation resembling a GVH (graft versus host) reaction. Repeated challenge through re-inoculation induces "bradyphylaxis" (progressively diminishing protection). On histopathological examination intense congestion is found, with haemorrhages in the lungs, liver, spleen and kidneys.

Animals↗
PubMedDate not supplied

Specificity of lymphocytotoxic antibodies in AIDS and pre-AIDS patients.

The number of T helper and T suppressor cells (determined with monoclonal antibodies) and the presence of serum lymphocytotoxic antibodies with T helper and T suppressor specificities were determined in 3 AIDS and 10 pre-AIDS patients and in 6 healthy homosexual and 17 healthy heterosexual controls. The 13 patients were 8 homosexuals and 5 drug addicts. Lymphocytotoxic antibodies were detected in all of the symptomatic individuals (AIDS and pre-AIDS) but in only 1 (6%) of the healthy heterosexual controls. Lymphocytotoxic antibodies in the patients ranged in titer from 125 to 625. The antibodies were detected at 15, 20, and 37 degrees C, but the reactivity at 37 degrees C was 20 to 40% lower than at 15 degrees C. All of the patients' antibodies reacted with both T helper and T suppressor cells, but in 9 sera the reaction was higher with the T helper and T (p less than 0.05). No correlation could be found between the patients' level of T helper lymphocytes or T helper/T suppressor cell ratios and their levels of lymphocytotoxic antibodies (p greater than 0.1). Sera of 7 patients and 3 of 9 healthy heterosexual controls reacted with non-T mononuclear cells (B cells plus monocytes). The degree of cytotoxicity with these cells did not correlate with the levels of lymphocytotoxic antibodies to T cells.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

T cell receptor V-segment frequencies in aged individuals.

The T V alpha and V beta cell specificities repertoire usage in aging subjects was studied by the use of seven different monoclonal antibodies specific for defined regions of the T cell receptor (TCR). Except for the V beta 8 subfamily, no differences were observed in the frequency of T cells bearing selected V alpha beta epitopes, between old and control subjects.

Adult↗
PubMedDate not supplied

T cell receptor V-segment frequencies in peripheral CD8+ T cells in aging.

Infections are a major cause of illness and death amongst elderly people. Peripheral blood CD8+ T lymphocytes --which play a crucial role in host defence against viral infections--, are divided in subsets based upon the expression of several cell and activation markers. In senescence changes and variations in peripheral CD8+ T lymphocyte compartment have been described, and such a decrease in the CD8+CD45RA+ lymphocytes. In this report the T V alpha and Vbeta cell specificities repertoire usage in aging subjects were studied by the use of seven different monoclonal antibodies specific for defined regions of the TCR. Except for the Vbeta6subfamily, no differences between old and control subjects in frequency of T cells bearing selected V alphabeta epitopes, were observed.

Adolescent↗
PubMedDate not supplied

Epidemiology and inmunogenetics in recently diagnosed Venezuelan children with insulin-dependent diabetes mellitus.

Genetic and immunological markers in children with Type I diabetes have not been studied previously in Venezuela. We evaluated 91 newly diagnosed IDDM children mean age 7.8 +/- 4.5 (range 0.8-20.8 years), 51 females and 40 males. Eleven percent of first degree relatives had a family history of Type I IDDM; 56.7% had had upper respiratory infection prior to diagnosis and 12.7% had had either mumps or varicella. Peak incidence of disease was found in February and March and August to October. Eighty seven percent had HLA-DR3 and/or DR4 vs 36% of the Venezuelan general population; 81.6% were HLA-DQW2 and/or HLA-DQW8. We found 55.9% to have positive islet cell antibodies (ICA) with 4 of these having a positive complement fixation test. Three patients (7.9%) were found to have positive insulin autoantibodies. Only 3 out of 11 HLA-identical siblings had positive ICAs, while none had positive insulin autoantibodies. One of them also had a positive complement fixation test; this subject developed IDDM. No positive serotypes for enterovirus (Coxsackie-B) were found in our patients, but we detected 11 cases with elevated titers for cytomegalovirus antibodies and positive antibodies for measles, mumps, herpes and varicella were found in some children. These data confirm that most of our Type I diabetics carry HLA-DR3 or DR4 and that the heterozygous DR3/DR4 phenotype is markedly increased in this population; they also indicate that DR3QW2 and DR4QW8 are associated with increased risk in our population.

Adolescent↗