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Biomedical subjects

E Cuende

Publications and source records attributed to E Cuende.

14 recordsLinked to original sources
PubMed1993

Programmed cell death by bcl-2-dependent and independent mechanisms in B lymphoma cells.

Programmed cell death (PCD) or apoptosis is a common form of cellular demise during embryogenesis, tumorigenesis and clonal selection in the immune system. The bcl-2 proto-oncogene has been recently implicated as a potential physiological regulator of the PCD pathway. Gene transfer studies have shown that overexpression of bcl-2 blocks apoptosis mediated by several stimuli in cultured cell lines and promotes the survival of B and T lymphocytes in transgenic mice. However, it remains unclear whether under normal conditions bcl-2 is responsible for controlling cell death. We have investigated the role of bcl-2 in the antimembrane IgM (mIgM)-induced apoptotic death of WEHI-231 B cell lymphoma, a model that mimics clonal deletion of immature B cells by antigen. Signalling of mIgM receptors triggered downregulation of both bcl-2 RNA and protein, and induced apoptosis in WEHI-231 B cells. This effect appeared to be specific since (i) the levels of beta 2-microglobulin and beta-actin RNA remain unchanged and (ii) signalling of the apoptosis-resistant B cell lymphoma line BAL-17 with anti-mu was not associated with downregulation of bcl-2 RNA. However, stable expression of bcl-2 by transfection did not rescue WEHI-231 B cells from apoptosis, yet WEHI-231 cells overexpressing bcl-2 were more resistant to programmed cell death induced by heat-shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Apoptosis↗
PubMed1993

Bone changes in postmenopausal Spanish women.

Total body bone mass (TBBM), axial bone mass (trunk = chest and spine), and peripheral bone mass (arms and legs) were determined in 258 normal, slow bone mass loser, postmenopausal women, as determined by previous biochemical studies, in order to study the degree of bone mass reduction due to menopause. The subjects of this study were divided into 5-year groups on a year-since-menopause basis. The first group corresponded to 1-5 years since menopause, and the last group to 25 years or over since menopause. An important and significant reduction in trunk bone mass (-12.3%, P < 0.001) and TBBD (-5.8%, P < 0.002), without changes in head, arms, and legs was observed in the first 5-year group. In the next 5-year group, a significant reduction was observed in all body areas, but at a higher rate in the peripheral skeleton (-9% in arms and -7.3% in legs). A slow down in bone mass loss was observed in the period between 10 and 25 years since menopause. These values became significant again after 25 years since menopause at the axial (-28.9%, P < 0.001) and TBBD (-20.3%, P < 0.05) level. Aside from providing percentages of bone mass reduction with respect to age and time since menopause, these data also indicate that measurements of specific body areas may not be extrapolated to others due to different loss in different body areas, and that there is a marked bone loss rate in the axial skeleton in the first 5 years since menopause.

Absorptiometry, Photon↗
PubMed1993

Candida arthritis in adult patients who are not intravenous drug addicts: report of three cases and review of the literature.

Candida species are an uncommon cause of infectious arthritis, although the frequency has increased during recent years. Three cases of septic arthritis caused by Candida species are reported, and the literature is reviewed. The first patient developed a popliteal cyst infected by Candida albicans after multiple intravenous antibiotic treatments. The second patient had acute myelogenous leukemia and experienced knee arthritis after chemotherapy, and the third suffered oligoarthritis after a second heart transplantation. All patients received treatment with a standard dose of intravenous amphotericin B. Responses were achieved only in the first two cases; the third patient died despite therapy. Thirty-six previously reported Candida arthritis cases are reviewed, and epidemiologic, diagnostic, therapeutic, and prognostic features are analyzed. Cases are divided into two categories: direct inoculation of fungus and hematogenously disseminated disease; these two categories are compared in terms of sex, age, pathogen species, treatment, and survival. Arthritis induced through direct inoculation of fungus is seen in older individuals, is more frequently produced by species other than C albicans (Candida parapsilosis especially), and has a better prognosis than arthritis caused by disseminated candidiasis. Arthritis can be resolved even in the persistence of the systemic disease. It is believed that the first case of Baker's cyst infected by C albicans and the first case of Candida arthritis in a heart transplant patient are reported here.

Adolescent↗
PubMed1993

Compartmentalization of the peripheral immune system.

The periphery of the immune system--as opposed to the central lymphoid organs--contains inhomogeneously distributed B and T cells whose phenotype, repertoire, developmental origin, and function are highly divergent. Nonconventional lymphocytes bearing a phenotype that is rare in the blood, spleen, or lymph nodes of undiseased individuals are encountered at high frequency in different localizations, e.g., alpha/beta TCR+CD4-CD8- cells in the bone marrow and gut epithelium, particular invariant gamma/delta TCR+CD4-CD8 alpha+CD8 beta- and gamma/delta TCR+CD4-CD8 alpha-CD8 beta- T cells in various epithelia, or CD5+ B cells in the peritoneum. The antigen receptor repertoire is different in each localization. Thus, different gamma/delta TCR gene products dominant in each site, and the proportion of cells expressing transgenic and endogenous alpha/beta TCR and immunoglobulin gene products follows a gradient, with a maximum of endogenous gene expression in the peritoneum, intermediate values in other peripheral lymphoid organs (spleen, lymph nodes), and minimum values in thymus and bone marrow. Forbidden T cells that bear self-superantigen-reactive V beta gene products are physiologically detected among alpha/beta TCR+CD4-CD8- lymphocytes of the bone marrow, as well as in the gut. Violating previous ideas on self-tolerance preservation, self-peptide-specific gamma/delta T cells are present among intestinal intraepithelial lymphocytes, and CD5+ B cells produce low-affinity crossreactive autoantibodies in a physiological fashion. It appears that, in contrast to the bulk of T and B lymphocytes, certain gamma/delta and alpha/beta T cells found in the periphery, as well as most CD5+ B cells, do not depend on the thymus or bone marrow for their development, respectively, but arise from different, nonconventional lineages. In addition to divergent lineages that are targeted to different organs guided by a spatiotemporal sequence of tissue-specific homing receptors, local induction or selection processes may be important in the diversification of peripheral lymphocyte compartments. Selection may be exerted by local antigens, antigen-presenting cells whose function varies in each anatomical localization, cytokines, and cell-matrix interactions, thus leading to the expansion and maintenance of some clones, whereas others are diluted out or deleted. The spatial compartmentalization of lymphocytes in different microenvironments has major functional consequences and leads to a partial fragmentation of immunoregulatory circuits at the local level. Lymphocytes residing in certain antigen-exposed compartments are likely to combat tissue-specific pathogens or self-proteins.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

[Still's disease in adults and polymyositis. An infrequent association].

A case of coexistence of adult onset Still's disease and idiopathic inflammatory myopathy is reported in a patient with antecedent of Graves-Basedow disease. Although myalgias are common during the flares of adult onset Still's disease, a review of literature only disclosed two previous cases of polymyositis associated to adult onset Still's disease. A high index of suspicion is needed in order to diagnose such a rare association which has relevant prognostic and therapeutic implications. Treatment with methotrexate was started in order to control myopathy, resulting in improvement of both polymyositis and adult onset Still disease. A possible role of methotrexate in the management of adult onset Still's disease is suggested.

Adult↗
PubMed1992

Inability of IL-2 and IL-10 to counteract B cell clonal deletion.

The B cell antigen receptor (BCR) delivers inhibitory signals in nascent B cells leading to the establishment of tolerance via clonal deletion or clonal anergy depending upon the type of antigen to which the B cells are exposed. In previous work, it has been demonstrated that activated Th2 cells, as well as some recombinant lymphokines, prevent the inhibition of growth and subsequent cell death induced through the BCR in model B cell lymphomas. Herein, we extend this work to another Th2 lymphokine, IL-10, that in contrast to IL-4 does not interfere with the deletion promoted by IgM crosslinking. The effect of individual lymphokines has also begun to be analyzed in a transgenic model of B cell clonal deletion. To this end, we have administered a recombinant vaccinia virus producing human IL-2 to mice expressing an autoreactive H-2Kk,b-specific transgenic IgMk and found that IL-2 does not abrogate B cell deletion in vivo.

Animals↗
PubMed1992

Interleukin-2: a possible trigger for autoimmunity.

High doses of recombinant interleukin-2 (IL-2) may induce autoimmune lesions in patients receiving experimental cancer treatment. In most cases, the manifestation of autoaggression is transient and organ-specific, predominantly affecting the thyroid gland. Only a fraction of the patients are concerned; most individuals (around 90%) do not develop any signs of autoimmunity. Apparently, endogenously hyperproduced IL-2 may also be implicated in the pathogenesis of autoaggression, since active phases of such disparate autoimmune diseases, like multiple sclerosis and systemic lupus erythematosus, are accompanied by elevated IL-2 serum levels. Taking into account that immunological self-tolerance is maintained by several distinct mechanisms, we investigated whether IL-2 would interfere with clonal deletion or clonal anergy in vivo. In several experimental systems, IL-2 failed to abolish clonal deletion in the murine thymus or in the peripheral T-cell compartment. IL-2 did not affect the clonal deletion of self-reactive B cells in the bone marrow either. In contrast, IL-2 was found to be effective in abrogating clonal anergy of non-deleted self-specific T cells. Only in the presence of high frequencies of self-specific, potentially autoreactive T cells, IL-2 induces autoimmune lesions. Thus, IL-2 interferes with a mechanism of self-tolerance that guarantees the inactivation of T cells that for some reason have 'escaped' clonal deletion. If these data, obtained in the murine system, are extrapolated to man, then it may be stated that the T-cell repertoire of most individuals has been completely purged from self-reactive cells. Only in the presence of a non-deleted, anergic, potentially auto-reactive T-cell population, could organ-specific disease be induced by IL-2.

Animals↗
PubMed1992

Prevention of B cell clonal deletion and anergy by activated T cells and their lymphokines.

B cell tolerance is described as the absence of a measurable antibody forming response to an antigenic challenge. The establishment of antigen-specific tolerance requires, by definition, engagement of the B cell antigen-specific receptor. However, only in some circumstances does this engagement lead to tolerance, while in others it produces B cell activation and secretion of immunoglobulins. Several mechanisms occur naturally in vivo abrogating the expression of deleterious autoantibodies and contributing to the state of self-tolerance. In this review, we will examine different ways in which B cell tolerance can be broken, focusing on evidence showing that activated-T cells and/or their lymphokines can prevent B cell clonal deletion and thus have a potential role in the pathogenesis of autoimmune diseases. This approach is based on the well-known association of several lymphokines, such as IL-1, IL-2, IL-4, IL-5, and type I interferons, with autoimmune phenomena in vivo.

Animals↗
PubMedDate not supplied

Chronic recurrent multifocal osteomyelitis: report of a case with epiphyseal and metaphyseal involvement.

Chronic recurrent osteomyelitis is a recognized clinicopathological entity with typical radiographic findings in the metaphyses of the long bones. Epiphyseal lesions usually are small and may easily be overlooked. Bone scintigraphy is helpful in identifying multiple lesions whether symptomatic or not. The diagnosis is one of exclusion without pathognomonic findings. Recognition of the condition is important to avoid treatment with antibiotics and repeated operations.

Ankle Joint↗