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Biomedical subjects

R E Duque

Publications and source records attributed to R E Duque.

15 recordsLinked to original sources
PubMed1992

Reduced expression of CD20 antigen as a characteristic marker for chronic lymphocytic leukemia.

The surface antigens expressed by the cells of chronic lymphocytic leukemia (CLL) are well known. Most CLL are monoclonal B-cell lymphoproliferative disorders characterized by the coexpression of B-cell antigens and CD5, an antigen present predominantly on T cells. Very little attention, however, has been paid to the quantitative characteristics of the expression of B-cell antigens in CLL. In this study, we used flow cytometry to analyze the expression of CD20, a well-known B-cell-associated antigen, in lymphocytes from 42 cases of CLL and its tissue counterpart, small lymphocytic lymphoma (SLL), and compared the results with results obtained from the analysis of 21 follicular lymphomas, 20 hyperplastic reactive nodes, and 26 samples of normal peripheral blood. The intensity of CD20 expression in the CLL/SLL cells was significantly lower than that of B cells in the other categories. This antigen expression abnormality does not appear to be a universal phenomenon in CLL/SLL, since CD19, another pan-B antigen, was expressed in CLL/SLL at levels higher than those in follicular lymphomas and comparable to those in reactive lymph nodes. These results indicate that the low CD20 expression can be used as a marker for CLL/SLL. The few cases exhibiting intense CD20 expression may represent a biologically different disease. CLL/SLL cells faintly expressing CD20 also show concomitant low CD5 expression in a manner not observed in normal CD5-expressing B cells.

Adult↗
PubMed1990

Biclonal composite lymphoma. A multiparameter flow cytometric analysis.

A case of composite, biclonal lymphoma detected and characterized by multiparameter flow cytometric analysis is presented. Analysis of cell surface immunophenotype and cell size, as assessed by forward light scatter, revealed that two populations of cells were present. The small cells were monoclonal kappa-positive cells admixed with reactive T and B cells. The large cells reacted solely with anti-lambda antibodies. Dual-color and dual-parameter (surface vs DNA) analysis further showed that the small, kappa-positive cells coexpressed CD5 and were diploid, with an estimated synthetic (S) fraction of 2.2%. The predicted histologic pattern was malignant lymphoma, small lymphocytic. In contrast, the large lambda-positive cells were both hyperdiploid and tetraploid with an estimated S fraction of 18%. On the basis of this multiparametric analysis, the predicted histologic pattern for the latter component was malignant lymphoma, diffuse large-cell type. Subsequent histologic examination confirmed the predicted pattern in both cases.

Aged↗
PubMed1989

High-grade B-cell lymphoma presenting as polyserosal disease. Diagnosis by flow cytometry.

Two patients presenting with anasarca were found to have aggressive B-cell lymphoma. No bulky disease was detected. The diagnosis was rapidly established by the flow cytometric analysis of cell surface immunophenotype and cell cycle fractions of pleural or peritoneal cells. Such presentation of lymphoma is unusual and previously undescribed, and it may have a significant negative prognostic impact. The authors' observations indicate that lymphoma be included in the differential diagnosis of anasarca and that flow cytometry can be useful for a fast confirmation of the diagnosis.

Aged↗
PubMed1989

Immunophenotypic characterization of an unusual T-cell lymphoma presenting as anterior uveitis. A clinicopathologic case report.

A 54-year-old woman presented with a unilateral, anterior uveitis that progressed to hypopyon over 4 months despite treatment with steroids. One hundred percent of the cells collected from aspirates of the anterior chamber of the affected eye were morphologically large granular lymphocytes. The aspirated cells were demonstrated by flow cytometry to be a uniform population of T lymphocytes with a diploid genome and an S fraction of 2.3%. On further investigation, the patient was found to have an extensive abdominal malignant lymphoma with the same immunophenotype but different morphologic features than the anterior chamber lymphoid infiltrate. In contrast to the cells in the anterior chamber, the abdominal tumor was highly aggressive as indicated by the cellular morphologic features and the S fraction of 43%. DNA hybridization studies of the abdominal lymphoma demonstrated a T beta 2 T-cell receptor gene rearrangement. The use of these modern diagnostic methods should facilitate the diagnosis of intraocular lymphomas and may have important therapeutic and prognostic implications in the future.

Diagnosis, Differential↗
PubMed1989

3-deaza-adenosine inhibition of stimulus-response coupling in human polymorphonuclear leukocytes.

In an effort to define better the functional role of S-adenosyl-methionine-mediated methylation reactions in modulating polymorphonuclear (PMN) functional responses to chemotactic stimuli, we investigated the effects of 3-deaza-adenosine (3-DZA), a known inhibitor of methylation reactions in phagocytic cells, on formyl methionyl-leucyl-phenylalanine (FMLP)-induced responses in human PMN leukocytes. Using the fluorescent cyanine dye 3,3'-dipropylthiocarbocyanine (di-S-C3-(5)) as an optical probe of membrane potential we observed that 3-DZA at concentrations that inhibit FMLP-induced O2- production does not significantly alter FMLP-induced changes in transmembrane potential. Additional studies showed an inhibitory effect of 3-DZA on FMLP-induced PMN pinocytosis and to a lesser degree on FMLP-induced degranulation. However, pretreatment of PMNs with 3-DZA did not alter FMLP-induced changes in Quin-2 fluorescence, an indicator of changes in intracellular calcium levels. These findings demonstrate a dissociation between chemotactic factor-induced cell membrane depolarization, changes in intracellular calcium, and specific neutrophil functional responses and suggest that chemotactic factor-induced changes in transmembrane potential and intracellular calcium are independent of chemotactic factor-induced methylation reactions. Furthermore, 3-DZA did not alter phorbol myristate acetate induced O2- production or fluid pinocytosis indicating a stimulus specificity for the inhibitory effects of this agent on O2- production.

Aminoglycosides↗
PubMed1988

Reduced oxidative function in gingival crevicular neutrophils in periodontal disease.

Measurable amounts of viable and functional polymorphonuclear neutrophils (PMNs) are recovered from pooled washings of the gingival crevice of healthy individuals. In the present study, we have assessed the ability of the PMNs removed from single healthy or diseased pocket sites to mount an oxidative burst when challenged with phorbol myristate acetate (PMA) and compared these activities with each other and with those obtained with autologous peripheral-blood PMNs. The oxidative burst after PMA stimulation was evaluated by using methods developed for the flow cytometer. The results showed that the PMNs collected from untreated disease sites were minimally responsive to PMA when compared with peripheral-blood PMNs collected at the same time from the same individual. Thus, whereas the peripheral-blood PMNs exhibited significantly lower resting oxidative product formation and a 500% increase when stimulated with PMA, all gingival-crevicular PMNs exhibited significantly higher resting formation of oxidized products but only a 150% increase after PMA stimulation. PMNs obtained from a consistently healthy site had significantly higher resting production of oxidized products and were able to mount the greatest absolute increase in oxidized products after PMA stimulation when compared with PMNs collected from diseases sites. Mechanical debridement of these diseased sites, which both reduced the bacterial numbers and restored clinical health, resulted in the recovery of gingival-crevicular PMNs that exhibited an oxidative burst more typical of that observed in PMNs obtained from healthy gingival sites and from the peripheral blood. This suggested that the PMNs collected from the diseased sites either had been exhausted by the large numbers of bacteria present in these sites or had been specifically inhibited by these bacteria.

Debridement↗
PubMed1987

Measurement of antineutrophil antibodies by flow cytometry: simultaneous detection of antibodies against monocytes and lymphocytes.

We describe a flow cytometric technique which detects the presence of antineutrophil antibodies (NABs) in human serum. The technique provides a qualitative as well as a semiquantitative screen and provides an excellent method for monitoring the presence of antineutrophil antibodies in patients with suspected autoimmune neutropenia. Using light-scatter gating, individual populations consisting of neutrophils, monocytes, and lymphocytes can be examined simultaneously for the presence of antibody. The methodology utilizes an indirect immunofluorescence technique with FITC-labeled goat antihuman F(ab')2 antibody and fixed leukocyte suspensions. Furthermore, by utilizing class-specific FITC-labeled second antibody, significant information can be ascertained regarding the class, cell specificity, and quantity of detected antibody. Formalin fixation of neutrophils prevented pinocytosis of the fluorochrome, significantly reducing background fluorescence. Twenty-five normal subjects provided baseline antibody levels for each class. Of 92 patients with suspected autoimmune neutropenia, 27 had class IgG alone and seven were positive for both IgG and IgM class NABs. During treatment, IgG levels varied. IgM NABs alone were detected in four patients. Fifty-four patients had undetectable antibody. Antibodies were detected against monocytes in several of the IgG-positive patients. Two sera contained both IgA and IgG NABs. One serum contained IgA and IgG antibodies against monocytes. No IgD antibodies were detected in any sera tested. Some sera tested contained antibodies against lymphocytes--however, only in those sera which also contained antibodies to other cell types.

Autoantibodies↗
PubMed1987

Quantitative assessment of neutrophil function by flow cytometry.

The use of flow cytometry (FCM) to quantitatively assess neutrophil function is reviewed. The methodology is capable of measuring a number of parameters involved in the oxidative pathways that form the basis of the activated neutrophil's contribution to the host defense mechanism. These events are summarized and some findings, such as in patients with chronic granulomatous disease, are discussed. FCM study of neutrophil function requires smaller numbers of cells than do traditional methods, which makes it particularly useful in the assessment of small fluid samples or in the evaluation of multiple parameters, and has the advantage that cell purification procedures are not essential.

Flow Cytometry↗
PubMed1986

Site-dependent phenotypic heterogeneity in peripheral T-cell lymphoma.

Peripheral T-cell lymphomas constitute a heterogeneous population of postthymic T-cell malignancies. Characteristically, they present a varied phenotypic expression, which can be helpful in establishing the diagnosis. A case of a peripheral T-cell lymphoma in a 76-year-old man is described. The malignant cells in the skin and bone marrow were of the T4 (helper/inducer) phenotype, yet they did not express pan-T-cell antigens, such as T11, or functional E rosettes. In a biopsy specimen from a lymph node, however, the malignant cells had a helper/inducer phenotype and also expressed the pan-T-cell antigens T11 and Leu-5. Additionally, the malignant cells from the lymph node formed E rosettes. This study demonstrates the phenotypic heterogeneity of malignant T cells, which appears to be site-dependent.

Aged↗
PubMed1986

Inhibition of neutrophil activation by p-bromophenacyl bromide and its effects on phospholipase A2.

In an effort to elucidate the nature of the inhibitory effects of p-bromophenacyl bromide (pBPB) on neutrophil stimulation, we have examined its effects on several stages of stimulus-response coupling. Pretreatment of rat neutrophils with pBPB resulted in a dose- and time-dependent irreversible inhibition of both N-formylmethionyl-leucylphenylalanine (fMet-Leu-Phe)-induced lysosomal enzyme release and change in transmembrane potential. Inhibition of the biological responses to the chemotactic peptide fMet-Leu-Phe was not due to receptor inactivation since fMet-Leu-[3H]-Phe binding to the formyl peptide receptor was not significantly altered by pBPB pretreatment. Inhibition by pBPB of phorbol myristate acetate (PMA)-induced changes in transmembrane potential and the generation of superoxide (0-2) was also observed. pBPB treatment appeared to inhibit activation of the NADPH oxidase without a direct effect on the oxidase itself. This inhibitory effect was not accompanied by cell death or decrease in cellular titratable sulphydryl groups (at least at doses less than 20 microM). There was, however, significant inhibition of a membranous fraction of fMet-Leu-Phe-induced phospholipase A2 activity by pretreatment with 10 microM pBPB, although total cellular phospholipase A2 was only minimally (less than 20% inhibition) affected. These data would indicate that pBPB inhibits an early event associated with stimulus-response coupling in rat polymorphonuclear leukocytes (i.e. change in transmembrane potential). The inhibitory effects of pBPB may be secondary to the inhibition of a critical membranous fraction of cell bound phospholipase A2 activity or its activation, necessary for the initiation of cell activation.

Acetophenones↗
PubMed1985

Functional defects in phagocytic cells following thermal injury. Application of flow cytometric analysis.

Defective phagocytic cell function may partially account for the morbidity and mortality associated with thermal injury. In experimental thermal injury in the rat, small circulating blood volumes increase the difficulty in obtaining significant data. Furthermore, purification and or elicitation procedures have the potential for altering the cell surface characteristics and/or the functional response of the cell in question. We have examined the circulating neutrophils and pulmonary alveolar macrophages of anesthetized rats following a 16-20% body surface area scald injury to the shaved back. The circulating neutrophils of thermally injured rats were examined by flow cytometry following stimulation with phorbol myristate acetate (PMA) (100 ng/ml) in terms of the change in fluorescence intensity of the potentiometric cyanine dye, dipentyloxocarboxyanine and the formation of the oxidized product of 2',7'-dichlorofluorescin diacetate-loaded cells. The alveolar macrophages were examined after stimulation with PMA (100 ng/ml) in terms of the change in fluorescence intensity of the potentiometric dye, dipropylthiodicarbocyanine and the generation of superoxide production, as assessed by the superoxide dismutase inhibitable reduction of cytochrome c. Both cells exhibited a profound inhibition of cell function 4 hours after the insult, with partial return toward control values at later time points. Furthermore, the plasma of thermally injured rats, 4 hours after the burn was inhibitory to normal rat neutrophils. Fluorescent compounds suggestive of in vivo lipid peroxidation were maximally detectable at this time point. Further research is needed to establish the role of these products in the induction of phagocytic cell dysfunction.

Animals↗
PubMedDate not supplied

Oxidative product formation in irradiated neutrophils. A flow cytometric analysis.

The effect of irradiation on neutrophil oxidative function was evaluated using a flow cytometric assay of intracellular hydrogen peroxide (H2O2) production. This assay quantitates the H2O2-dependent conversion of the nonfluorescent compound, 2'-7'-dichlorofluorescein (DCFH), into fluorescent 2'-7'-dichlorofluorescein (DCF) on a single-cell basis. Intracellular H2O2 production in response to stimulation with phorbol myristate acetate was not affected by neutrophil irradiation at doses up to 2500 rad. In addition, irradiation of intracellular DCFH and aqueous 2'-7'-dichlorofluorescein diacetate (DCFH-DA) resulted in DCF production, which suggested that oxidative molecules produced by aqueous radiolysis were detected by this assay. This study indicates that radiation doses of 1500 to 2500 rad, which are sufficient to prevent induction of graft-versus-host disease by transfused blood components, are not deleterious to neutrophil oxidative metabolism.

Flow Cytometry↗