Biomedical subjects

E G Olivares

Publications and source records attributed to E G Olivares.

14 recordsLinked to original sources

PubMed2003

Influence of age, sex, and hepatitis C virus infection on peripheral blood lymphocyte subsets in stable kidney transplantation.

BACKGROUND: Young age and hepatitis C virus infection (HCVI) are believed to be risk factors in kidney transplantation recipients. The first group is treated empirically with an intensive immunosuppressive regimen, because it is considered to have high immune alloreactivity. The other cohort usually receives a less intensive regimen to avoid excessive immunosuppressive effects. Our aim was to investigate the influence of age, sex, and HCVI on immune status in stable kidney transplant recipients through measurement of peripheral blood lymphocyte subsets. METHODS: Absolute CD3+, CD3+, CD4+, CD3+, CD8+, CD19+, CD16+ CD3- lymphocyte counts and CD4/CD8 ratios were assessed at five time points in 65 stable kidney allograft patients over 12 months. The subsets were compared according to age, sex, and HCVI of the recipients. RESULTS: An inverse association was observed between recipient age and absolute CD19+ and CD3+ CD4+ lymphocyte counts, which was significant at all time points with respect to CD19+ counts, and at three time points with respect to CD3+ CD4+ counts. A significant positive association was observed between recipient age and absolute CD3- CD16+ lymphocyte counts at three time points. Female recipients showed significantly lower CD3+ CD8+ counts and significantly higher CD4/CD8 ratios than male recipients at four time points. HCVI recipients showed significantly lower CD16+ CD3- counts at four time points. CONCLUSIONS: We observed links between immune status and age, sex and HCVI in stable kidney transplant recipients that could offer new insights into recommendations for maintenance immunosuppression.

Age Factors↗

PubMed2001

Human decidual stromal cells express CD34 and STRO-1 and are related to bone marrow stromal precursors.

Decidual stromal cells (DSC) are the main cellular component of the human decidua, but thus far their ascription to a given cell lineage is uncertain. In previous studies, these cells have been isolated and maintained in culture, and their antigen phenotype has been analysed to determine their affiliation. However, the presence in the culture medium of high proportions of fetal calf serum (FCS) may inhibit the expression of some surface antigens. In the present study, we show by flow cytometry that CD34 is rapidly down-regulated in human DSC cultured in RPMI 1640 with 20% FCS. For this reason, we used fibroblast medium, which contains only a small proportion (2%) of FCS, to isolate and culture these cells. Under these conditions DSC exhibited a stable antigen phenotype highly similar to that of these cells in vivo. Flow cytometry results confirmed that DSC cultured in fibroblast medium expressed CD34 protein, and reverse transcription-polymerase chain reaction findings showed that they have CD34 mRNA. Decidual stromal cells were also positive for STRO-1, an antigen that identifies stromal precursors of the bone marrow which also expresses CD34. The expression of CD10, CD13, alkaline phosphatase and alpha-smooth muscle actin by DSC, and the absence of expression of CD14 and CD45, further confirmed their relationship with the stromal precursors.

ADP-ribosyl Cyclase↗

PubMed2000

Expression of molecules involved in antigen presentation and T cell activation (HLA-DR, CD80, CD86, CD44 and CD54) by cultured human osteoblasts.

BACKGROUND: Osteoblasts express the CD44 antigen and HLA class II antigens, molecules which, together with other costimulatory molecules such as CD80, CD86, and CD54, are involved in antigen presentation and T cell activation. The aim of this study was to investigate the expression of these molecules in human osteoblasts. METHODS: Human osteoblastic cells obtained from samples of normal bone obtained during mandibular osteotomy were isolated, maintained in culture, and characterized. The identity of the cells was confirmed by their alkaline phosphatase activity and their capacity to produce osteocalcin. Flow cytometry was used to examine the expression HLA-DR, CD80, CD86, CD44, and CD54 molecules involved in immune activities. RESULTS: We detected the expression of CD10, CD44, and HLA-DR antigens, molecules involved in antigen presentation in cultured osteoblastic cells. Although the cells were negative for CD45, the leukocyte common antigen and CD14 (an antigen detected on macrophages), they expressed CD54, CD80, and CD86 antigens, which are also involved in the mechanisms of antigen presentation to and activation of T cells. CONCLUSIONS: Our results suggest that osteoblastic cells or a subpopulation of these cells may have immune functions in bone. Further studies in which immune functions are assessed will be needed to test this hypothesis.

Adult↗

PubMed1999

Antigen phenotype of cultured decidual stromal cells of human term decidua.

We previously reported that decidual stromal cells (DSC) from early human decidua express antigens associated with hematopoietic cells and develop different immune functions. Here we study the antigenic phenotype of DSC from term decidua and compare it with the phenotype reported for DSC from early decidua. Decidual stromal cells were isolated from human term deciduas and maintained in culture until highly purified DSC cultures were obtained. Most term DSC, like most early DSC, expressed CD10. Term DSC expressed antigens specific for follicular dendritic cells (FDC), such as DRC-1 (CD21L) and HJ2, together with CD21, CD23 and CD80, which are detected on FDC as well. Also like early DSC, term DSC were negative for CD3, CD14, CD15 and CD45. Although early DSC were reported to be HLA-DR-positive and CD86-positive, these antigens were not expressed by term DSC. These discrepant results suggest that two types of cells, or cells at different stages of differentiation (decidualization) were selected during culture of decidual cells from different periods of gestation. This possibility was further supported by the finding that term DSC expressed desmin and prolactin, two markers of decidualization, whereas these molecules have not previously been detected in early DSC.

Antigens, CD↗

PubMed1999

Human decidual stromal cells express alpha-smooth muscle actin and show ultrastructural similarities with myofibroblasts.

Previous reports in human and mouse material demonstrated that decidual stromal cells expressed antigens associated with haematopoietic cells, exerted immune functions, and originated from bone marrow. These findings suggested that these cells belonged to the haematopoietic lineage. We purified and expanded in culture precursors of human decidual stromal cells, and found in electron microscopic images that the ultrastructure of these cells was similar to that of myofibroblasts, which are of mesenchymal origin. The relationship between these two types of cell was confirmed by the detection (by flow cytometry) in the decidual precursors of alpha-smooth muscle actin, a contractile microfilament expressed solely by smooth muscle cells, myofibroblasts and related cells. This filament was also detected in decidual stromal cells decidualized in vitro by the effect of progesterone. We also found vimentin in decidual precursors and decidualized cells. This intermediate filament has been previously reported to be expressed by all decidual stromal cells and also by myofibroblasts. Desmin, another intermediate filament expressed by myofibroblasts, was not detected in the decidual precursors; however, this filament was observed in decidualized cells. The expression of alpha-smooth muscle actin by decidual stromal cells was also found by immunostaining in cryostat sections of early decidua. Our results suggest that decidual stromal cells are related to myofibroblasts.

Actins↗

PubMed1997

Immunospecificity of albumin detected in 1.6 million-year-old fossils from Venta Micena in Orce, Granada, Spain.

The Orce skull fragment from southern Spain, dated at 1.6 Myr, has been a subject of heated controversy since it was first discovered in 1982. If it is hominid, as its discoverers contend, it is by far the oldest fossil hominid yet found in western Europe and implies that human populations settled this region much earlier than was previously realized. Numerous stone artifacts found at the Orce sites provide evidence that hominids were indeed present there in the Lower Pleistocene. Some paleontologists maintain that the 8 cm diameter occipital fragment is from a horse, not a hominid. Two independent investigations of the residual proteins in the skull were undertaken, one at the University of Granada in Spain, the other at the University of California, San Francisco. Two immunological methods of comparable sensitivity were employed for detection and species attribution of protein extracted from fossil bone: the Granada team used an enzyme-linked-immunosorbent assay (ELISA), and the UCSF team used a radioimmunoassay (RIA). Both teams obtained reactions characteristic of human albumin in the Orce skull and horse albumin in some of the horse fossils. These results support the lithic evidence that hominids were living in Andalusia 1.6 million years ago.

Albumins↗

PubMed1997

Phagocytosis by fresh and cultured human decidual stromal cells: opposite effects of interleukin-1 alpha and progesterone.

Flow cytometry and transmission electron microscopy have been employed to show that a proportion of fresh and cultured human decidual stromal cells phagocytose latex particles. Phagocytosis of Escherichia coli by cultured decidual stromal cells was, however, very low. Stimulation of cultured decidual stromal cells with interleukin-1 alpha enhanced phagocytosis of both latex particles and E. coli. In contrast, when decidual stromal cells were cultured with progesterone under decidualizing conditions, phagocytic activity was reduced. These results suggest the existence of an immune-endocrine circuit involving decidual stromal cells.

Antigens, CD↗

PubMed1997

Lymphocytes of human term decidua decrease cell adhesion to a plastic substrate.

Although human decidual lymphocytes have been widely studied, their function and possible interaction with trophoblast are still unclear. Here we show that whereas human early (EDL) and term (TDL) decidual lymphocytes were unable to kill human trophoblast by necrosis (assessed by the 51Cr-release assay) or apoptosis (DNA fragment assay), TDL but not EDL decreased trophoblast adhesion to a plastic substrate as determined by a [3H]thymidine assay. This effect, however, was not selective for trophoblast, as TDL also decreased the adhesion to plastic of human decidual stromal cells and HeLa cells. Our results suggest that TDL may play a role in placental detachment during parturition by decreasing trophoblast or decidual stromal cell adhesion.

Apoptosis↗

PubMed1997

Cultured human decidual stromal cells express B7-1 (CD80) and B7-2 (CD86) and stimulate allogeneic T cells.

The origin and function of decidual stromal cells (DSC), the main cellular component of the decidua, are uncertain. Although the general consensus is that they are fibroblastic cells involved in fetal trophoblast nutrition, several authors have demonstrated that these cells can carry out immunological functions and that at least a subpopulation of them may be of hematopoietic origin. Human DSC precursors or predecidual cells (preDSC) purified by expansion in culture express a surface phenotype recalling that of dendritic cells. In the present study, we show by flow cytometry that these cells also express B7-1 (CD80) and B7-2 (CD86), two antigens involved in the costimulation of T cells by antigen-presenting cells. Cultured DSC were also able to stimulate allogenic T cells in vitro. Using an immunohistochemical technique, we found that in cryostatic sections of early human decidua, CD80 and CD86 were expressed mainly by DSC located around the decidual vessels, a location compatible with preDSC rather than fully differentiated DSC. Our results suggest that preDSC are involved in antigen presentation.

Antigen Presentation↗

PubMed1996

Immune phenotype and cytotoxic activity of lymphocytes from human term decidua against trophoblast.

Flow cytometric data were used to compare the phenotype of term decidual lymphocytes and peripheral blood lymphocytes. Unlike peripheral blood lymphocytes, a significant percentage of CD3+, CD4+, CD8+ and CD16+ term decidual lymphocyte populations expressed the CD69 activation marker. The relative proportions of CD38 in CD3+, CD4+ and CD8+ populations were more than twice as large in term decidual lymphocytes as in peripheral blood lymphocytes. As reported for early decidual lymphocytes, the expression of CD38 and CD69 by term decidual lymphocytes suggests that these cells are also regionally activated. However, term decidual lymphocytes showed no spontaneous cytotoxicity against normal trophoblast or its tumoral counterpart, JEG cells. After stimulation with interleukin-2, these lymphocytes became cytotoxic, as did peripheral blood lymphocytes. The relevance of this latter result to the immune control of the physiological and pathological invasion of the decidua by the trophoblast is discussed.

ADP-ribosyl Cyclase↗

PubMed1995

Constitutive secretion of interleukin-6 by human decidual stromal cells in culture. Regulatory effect of progesterone.

PROBLEM: Although several studies have demonstrated that decidual stromal cells (DSC) can secrete cytokines in culture, none of these studies documented the purity of the cultures. Since other cells of the decidua, such as macrophages and epithelial cells, also produce cytokines, it is important to ensure purity of the culture so that cytokine production can be ascribed with confidence to DSC. METHOD: DSC from early human pregnancies were highly purified and maintained in culture. Basal secretion by these cells of IL-6, together with other cytokines considered critical for pregnancy (IL-1 beta, TNF alpha and IFN gamma), was measured with immunological techniques. RESULTS: We found that DSC in culture produce insignificant quantities of IL-1 beta, TNF alpha and IFN gamma, but appreciable amounts of IL-6. The production of this later cytokine was, however, inhibited by the effect of progesterone. CONCLUSIONS: Basal production of IL-6 by DSC may be involved in physiological functions at the maternal-fetal interface. Nevertheless, the secretion of this cytokine is regulated by progesterone, probably to prevent excessive production of this cytokine from triggering an inflammatory response that might compromise pregnancy.

Antigens, CD↗

PubMed1993

Expression of adhesion molecules by endothelial cells of early human decidua.

The expression of adhesion molecules by endothelial cells (EC) of early human decidua was studied with monoclonal antibodies and the immunoperoxidase technique. Although E-selectin, INCAM-110 and VCAM-1 were poorly detected on decidual EC, ICAM-1, P-selectin and DR antigens were highly expressed by these cells, some of which showed high endothelial venule-like morphology. Our results suggest that decidual EC are activated, and are probably involved in the active recruitment of leucocytes.

Cell Adhesion Molecules↗

PubMed1993

Application of flow cytometry to the study of antiphagocytic properties of Klebsiella pneumoniae capsular polysaccharide.

We used flow cytometry to compare the effects of whole cells and capsular polysaccharides of Klebsiella pneumoniae on the phagocytic ability ot polymorphonuclear leukocytes. Our results showed a light decrease in phagocytic activity in the presence of capsular polysaccharides, but a marked decrease with whole cells. Our findings suggest that the resistance to phagocytosis in these microorganisms is not due exclusively to their capsule, as claimed by other authors.

Flow Cytometry↗

PubMed1991

Prevalence and prediction of hypoxemia in children with respiratory infections in the Peruvian Andes.

To determine the effect of respiratory infections on oxyhemoglobin saturation in a high-altitude population, we recorded clinical signs, oxyhemoglobin saturation determined by pulse oximetry, and findings on radiographs of the chest of 423 children with acute respiratory infections; the children were living at an altitude of 3750 m in the Peruvian Andes. We defined hypoxemia as an oxyhemoglobin saturation value greater than 2 SD below the mean value for 153 well children in this population. Eighty-three percent of children with clinical bronchopneumonia, but only 10% of children with upper respiratory tract infection, had hypoxemia (p less than 0.001). Compared with previous studies of children living at lower altitudes, the presence of tachypnea was relatively nonspecific as a predictor of radiographically determined pneumonia or of hypoxemia, especially in infants. A history of rapid breathing was 74% sensitive and 64% specific in the prediction of hypoxemia, and performed as well as a standard World Health Organization case management algorithm in the prediction of radiographic pneumonia or hypoxemia. Radiographic pneumonia was not a sensitive predictor of hypoxemia or clinically severe illness. In contrast, the presence of hypoxemia was a useful predictor of radiographic pneumonia, with both sensitivity and specificity of 75% in infants. We conclude that acute lower respiratory tract infection in children living at high altitude is frequently associated with hypoxemia, and that oxygen should be administered to children with a diagnosis of pneumonia in these regions. Case management algorithms developed in low-altitude regions may have to be modified for high-altitude settings. In this setting, pulse oximetry is a good predictor of pneumonia. Because pulse oximetry is more objective and cheaper than radiography, its role as a clinical and investigative tool merits further exploration.

Acute Disease↗