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D Aguilar

Publications and source records attributed to D Aguilar.

At least 19 recordsLinked to original sources
PubMed2000

An ORF from Bacillus licheniformis encodes a putative DNA repressor.

The complete sequence of a reading frame adjacent to the endo-beta-1,3-1,4-D-glucanase gene from Bacillus licheniformis is reported. It encodes a putative 171 amino acid residues protein with either, low significant sequence similarity in data banks or the corresponding orthologue in the recently sequenced Bacillus subtilis genome. Computer analyses predict a canonical Helix-Turn-Helix motif characteristic of bacterial repressors/DNA binding proteins. A maxicells assay shows that the encoded polypeptide is expressed. A DNA-protein binding, assay performed by gel electrophoresis shows that the expressed protein specifically binds to Bacillus licheniformis DNA.

Amino Acid Sequence↗
PubMed1999

Pre-arrest heparinization and ventilation during warm ischemia preserves lung function in non-heart-beating donors.

BACKGROUND/PURPOSE: To solve the problem of donor scarcity, many attempts have been made including improved community education, relaxed organ acceptance criteria, increased reliance on single lung transplantation, and the use of partial organ donation. Unfortunately, these efforts have produced only modest increases in lung allograft availability; therefore, the so-called non-heart-beating organ donation must be considered. The aim of this study is to assess the viability of the non-heart-beating donor (NHBD) lung transplant rat model and determine the best strategy to manage the donor before and after cardiac arrest. METHODS: Fifty-five inbred Fischer rats were used as donors and recipients in an isogenic model of left lung transplantation. The rats were divided into 6 groups (n = 5): group I, normal controls without transplant; group II, heart-beating donor controls (HBD); group III, NHBD, no heparin, no ventilation during warm ischemia; group IV, NHBD, heparin, no ventilation; group V, NHBD, no heparin, ventilation; group VI, NHBD, heparin, ventilation. All lungs were stored at 4 degrees C for 4 hours. Animals were killed 24 hours after implantation. Gas exchange, pulmonary artery pressure, compliance, chest x-ray score, and histological score were assessed. RESULTS: Heparinized and ventilated animals during warm ischemia (group VI) had similar performance than those transplanted without warm ischemia time in a scenario of heart-beating donor (group II). Groups III, IV, and V transplanted lungs showed severe damage. CONCLUSIONS: The authors conclude that the rat lung transplantation model is useful to study the phenomena that occur in a setting of transplantation using NHBD and that heparinization and ventilation before cardiac arrest is the best strategy to manage non-heart-beating donors in this model.

Animals↗
PubMed1998

Design and validation of a new image analysis method for automatic quantification of interstitial fibrosis and glomerular morphometry.

Interstitial fibrosis and morphologic changes in kidney glomeruli, the structural effects of many diseases, lead to significant pathologic alterations. A reliable and objective method to accurately quantify the extent of interstitial fibrosis and the degree of alteration in glomerular morphology is needed for both clinical practice and experimental work. The morphometric methods of quantification described to date are time-consuming and require trained personnel. This article describes the design and validation of an image analysis-based application (Fibrosis HR) for automatically and rapidly quantifying interstitial fibrosis and glomerular morphology in the same tissue section stained with Sirius red. The image processing algorithms described herein automatically segment interstitial fibrosis and mesangial matrix using automatic thresholding and morphologic filtering. The glomerular region is extracted by a simple interactive step and an automatic mathematical morphology algorithm, whereas the glomerular tuft is automatically segmented with automatic thresholding and a sequence of Boolean and mathematical morphology operations. All extracted areas are automatically quantified in absolute (microm2) and relative (%) values. For validation of this method, interstitial fibrosis, mesangial matrix, and glomerular and glomerular tuft areas were manually segmented and their quantifications statistically compared with those obtained automatically. Statistical analyses showed significant intra- and interoperator variability in manual segmentation of interstitial fibrosis, mesangial matrix, and glomerular tuft areas. Automatic quantifications of the same areas did not differ significantly from their mean manual evaluations. There was no significant intra- or interoperator variability in the interactive identification of the glomerular region. In conclusion, Fibrosis HR produces robust, fully reproducible, accurate, objective, and reliable quantifications, which facilitate the evaluation of in vivo experimental models of renal interstitial and glomerular pathologies and improve the accuracy of clinicopathologic analyses of renal diseases in human biopsies.

Algorithms↗
PubMed1995

Influence of intrarenal deposits of ciclosporin A on acute renal transplant rejection.

Immunohistochemical techniques were used to study the presence of ciclosporin A (CsA) and leukocyte subsets in 36 posttransplant renal biopsy specimens histologically diagnosed as acute graft rejection. Glomeruli from patients with CsA deposits contained more leukocytes (p < 0.05) than glomeruli from tissues without deposits. In contrast, the interstitium from patients without deposits contained significantly more B lymphocytes than interstitia from kidneys with CsA deposits. In both glomeruli and interstitia, the CD4/CD8 ratios were higher in tissues without deposits, although the difference was not significant. The plasma levels of creatinine increased with the intensity of renal CsA deposits, and significantly more patients on hemodialysis had deposits as compared with patients not on hemodialysis. Our findings suggest two types of acute nonvascular rejection: (1) predominantly interstitial, with a good prognosis, characterized by low numbers of intrarenal CsA deposits and a predominance of B lymphocytes and (2) predominantly glomerular, with a poor prognosis, characterized by high levels of intrarenal CsA and a predominance of CD8-positive cells and macrophages.

Acute Disease↗
PubMed1995

Relationship between P-glycoprotein expression and cyclosporin A in kidney. An immunohistological and cell culture study.

P-glycoprotein (P-gp), encoded in humans by the mdr-1 gene, acts physiologically as an efflux pump to expel hydrophobic substances from cells. This glycoprotein is closely related to multidrug resistance in tumor cells and can be modulated by cyclosporin A (CsA). We investigated the relationship between CsA and P-gp in 52 renal allograft biopsies and in cultures of Madin-Darby canine kidney (MDCK) renal tubule cells to determine whether the intrarenal accumulation of CsA or chronic stimulation with the drug modified the expression of P-gp. Expression of P-gp and CsA was analyzed by immunohistochemistry. Immunostaining was evaluated semiquantitatively. Modulation of P-gp in MDCK cells after chronic stimulation with CsA for 7, 30, and 60 days was analyzed by flow cytometry. P-gp and CsA immunostaining in renal post-transplant biopsies showed considerable overlap in all cases (Spearman's test, r = 0.577, P < 0.001). After 7 days in vitro, the number of cells expressing P-gp increased progressively; a further increase in mean fluorescence was found after 60 days (P < 0.001, Student's t-test). Our findings suggest that in non-neoplastic cells, CsA may stimulate P-gp as a mechanism of detoxification. Individual differences in the adaptive responses to glycoprotein may be responsible for the appearance of nephrotoxicity or a CsA-resistant rejection reaction in cases of overexpression on lymphocytes and macrophages.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Presence of cytomegalovirus genome and leucocyte subsets in renal transplant biopsies. Relationship with prognosis.

The influence of immunosuppressant therapy and of the presence of CMV genome on the distribution of lymphoid subpopulations of the inflammatory infiltrate in renal graft rejection was analyzed, as was the role of both factors in the evolution and survival of the graft. The study included 22 patients treated with Cyclosporin A (CsA) and 22 patients treated with Azathioprine (AZA). Inflammatory infiltrate was studied by immunostaining with a panel of monoclonal antibodies, and CMV DNA was detected by in situ hybridization on tissue sections. In patients treated with CsA, increased cellularity was found at both glomerular and interstitial levels, consisting mainly of macrophages and T-cells, which was consistent with the higher rate of glomerulointerstitial rejection found in this group. In contrast, the vascular type of rejection predominated in AZA treated patients. However, the presence of CMV DNA did not influence the phenotype of the inflammatory infiltrate, and was not associated with any specific lesion. Furthermore, the final outcome of the renal graft was independent of the detection of CMV. Therefore, this study provides no evidence of any active role of the CMV genome in renal graft rejection, and suggests that therapy should be adapted to the type of rejection as defined on morphologic and immunophenotypic grounds.

Adult↗
PubMed1994

Immunohistochemical study of 30 cases of cyclosporin A-induced gingival overgrowth.

Immunohistochemical techniques were used to study the presence of cyclosporin A (CsA) and leukocyte subsets in 30 gingival biopsies of renal transplant subjects with gingival overgrowth (GO). Statistical analysis revealed significant differences in the total number of inflammatory cells determined by monoclonal antibody CD45, the monocyte/macrophage (CD68) subset, the plasmatic cells (EMA), and the total of T-lymphocytes (CD3) (P < 0.001, Student t test) between the treated subjects and the healthy control group. Differences were found in the helper/inducer T lymphocytes CD4 (P < 0.001 Student t test) and cytotoxic/suppressor T lymphocyte (CD8) (P < 0.01, Student t test) subsets between both groups. The CD4/CD8 ratio was greater in the transplant subjects than in the control group (1.82 +/- 0.16 versus 1.35 +/- 0.05 respectively) (P < 0.05 Student t test). There was no significant difference in the populations CD16+, CD57+, and CD20+. The CD45+ CD4+, and CD68+ cells increased in number along with the degree of GO. The number of epithelial cells/mm2 which displayed a deposit of CsA increased in accordance with the degree of GO (P < 0.05, Kruskal-Wallis's test). Likewise, the intraepithelial deposit of CsA in the GO region was found to be related to the inflammatory infiltrate CD4+, CD8+, and CD68+ (r = 0.7432; r = 0.7346; r = 0.77005, respectively). Our findings suggest that the intraepithelial deposit of CsA and the inflammatory infiltrate play a predominantly pathogenic role and are both related to the degree of GO.

Adult↗
PubMed1993

Mononuclear cell subsets in IgM mesangial proliferative glomerulonephritis. A comparative study with minimal change nephrotic syndrome and immunonegative mesangial proliferative glomerulonephritis.

Glomerular and interstitial leukocyte subpopulations were analyzed in renal biopsies from 18 patients with IgM mesangial proliferative glomerulonephritis (IgM MPGN), 19 patients with minimal change nephrotic syndrome (MC) and 10 patients with immune-negative mesangial proliferative glomerulonephritis (IN MPGN), by immunoperoxidase techniques with monoclonal antibodies. Mesangial cell proliferation was strongly correlated with absolute numbers of intraglomerular T lymphocytes (r = 0.71; p < 0.01) in IgM MPGN, but not in MC or IN MPGN. Significant differences were found in the numbers of macrophages, CD4- and CD8-positive glomerular cells (Student's t test p < 0.01, 0.05 and 0.01, respectively) in IgM MPGN, but not in MC or IN MPGN. The numbers of CD45-, CD3- and CD8-positive cells also differed in each patient group (ANOVA p < 0.01, 0.05 and 0.05, respectively), the greatest and smallest values appearing in IgM MPGN and MC, respectively. Multiple regression test showed initial proteinuria values in IgM MPGN to be closely dependent on the density of neutrophils, macrophages, T and B lymphocytes and CD4 cell inflammatory infiltrates (r2 = 0.92; p < 0.01). At the end of the follow-up, proteinuria in IgM MPGN, but not in MC or IN MPGN, was dependent on T cell infiltrate (r2 = 0.97; p < 0.01). Our findings suggest that proteinuria in IgM MPGN results from local mesangial damage rather than from the effects of a soluble circulating factor, as has been proposed for MC. The clinical and immunohistochemical differences observed between these two processes support the notion that they should be considered as separate entities.

Adult↗
PubMed1992

Detection of lipoarabinomannan as a diagnostic test for tuberculosis.

A coagglutination technique was established for the detection of lipoarabinomannan of Mycobacterium tuberculosis in human serum samples and evaluated for its utility in the diagnosis of tuberculosis at the Instituto Nacional de Enfermedades Respiratorias in Mexico City. The test had a sensitivity of 88% in patients with sputum-smear-positive active pulmonary tuberculosis. The sensitivity in patients with active pulmonary tuberculosis negative for acid-fast bacilli in sputum was 67%. Less favorable results were obtained for patients with AIDS and tuberculosis, with a sensitivity of 57%. The specificity in control patients with lung diseases different from tuberculosis and in healthy subjects was 100%. The positive predictive value was 100%, and the negative predictive value for patients with sputum-positive active pulmonary tuberculosis was 97%. The results of this study suggest that the detection of lipoarabinomannan is an accurate test for the diagnosis of pulmonary tuberculosis.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Diffuse sclerosing papillary carcinoma of the thyroid gland: immunohistochemical analysis of the local host immune response.

Surgical specimens from four patients with diffuse sclerosing papillary carcinoma of thyroid were examined by electronmicroscopy. In addition, immunohistochemical examination using a panel of monoclonal and polyclonal antibodies was carried out in order to investigate the expression of HLA-DR antigen, the presence of Langerhans' cells and the phenotypic characteristics of the inflammatory infiltrate. The ultrastructural study showed that the intraglandular dissemination, typical of this tumour, was due to massive lymphatic invasion. Many Langerhans' cells were observed among tumour cells and in the lymphoid infiltrates in proximity to tumour foci. HLA-DR expression was seen on macrophages, Langerhans' cells, endothelial cells, lymphoid cells, many tumour cells and in some non-neoplastic follicles close to tumour clusters and lymphoid infiltrates. The immunohistochemical analysis of the inflammatory infiltrates showed a high proportion of B- and T-cells, and moderate numbers of plasma cells. Our results suggest that the tumour-specific immune response can give rise to an autoimmune reaction involving non-neoplastic follicles. It is suggested that this could be one of the mechanisms responsible for immunofacilitation of tumour growth.

Adolescent↗