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A Orfao

Publications and source records attributed to A Orfao.

At least 19 recordsLinked to original sources
PubMed2001

Optimal number of reagents required to evaluate hematolymphoid neoplasias: results of an international consensus meeting.

At the ISAC 2000 Congress, the Clinical Cytometry Society organized a meeting of international experts to reach consensus on the minimum number of antibodies required for a full evaluation of hematologic and lymphoid neoplasias. A questionnaire was distributed prior to the meeting to numerous experts from US and European institutions and 13 responses were received. At the meeting, 25 individuals, including most of those who returned responses, participated in the discussions and voted on the issues presented. In chronic lymphoproliferative disorders (CLD), 9 antibodies (anti-CD5, CD19, kappa, lambda, CD3, CD20, CD23, CD10, and CD45) were deemed essential for initial evaluation by 75% of the participants. There was near unanimity that additional markers (selected from CD22, FMC7, CD11c, CD103, CD38, CD25, CD79b and heavy chains for B-cell disorders, and CD4, CD7, CD8, CD2, CD56, CD16, TCRa/b, and TCRg/d for T-cell disorders) would be needed to fully characterize CLD, although not every marker would be useful in all cases. Tissue lymphomas were believed to be similar to CLD, needing a minimum of 12--16 markers. However, for some cases, CD30, bcl-2, TdT, CD71, CD1a, and CD34 were cited as useful by the participants. Markers mentioned for plasma cell disorders included kappa, lambda, CD38, CD45, CD56, CD19, CD20, CD138, and heavy chains. Of 17 voting participants, 16 agreed that between 5 to 8 markers would be essential reagents for plasma cell disorders. For acute leukemia (AL), 10 markers (CD10, CD19, CD13, CD33, CD34, CD45, CD7, CD14, CD3, and HLADR) were considered essential by 75% of participants for initial characterization of the leukemia lineage. Most (>75%) agreed that at least one more B (CD20, CD22, CD79a, IgM), T (CD1a, CD2, CD4, CD5, CD8), myeloid (CD11b, CD15, CD64, CD117, myeloperoxidase), erythroid (CD36, CD71, glycophorin A), and megakaryocytic (CD41, CD61) reagents should be included in the essential panel. However, there was no agreement as to which was optimal. Thus, approximately 13--15 of those reagents would be considered essential in all cases of AL, whereas others (CD16, CD56, CDw65, TdT, and cytoplasmic CD3) were mentioned as useful in some cases. Almost all voting participants believed that the appropriate number of markers for complete characterization of AL would average 20--24. The majority of the responders (11 of 13) indicated that fewer reagents could be used in monitoring or staging patients with previously characterized disease, but not all ventured a specific number of reagents. From the above results, we conclude that the phenotypic analysis of hematologic and lymphoid neoplasia requires a rather extensive panel of reagents. Supplementary reagents might even be necessary if they prove to become relevant for diagnostic purposes. Reducing the number of antibodies could significantly compromise the diagnostic accuracy, appropriate monitoring, or therapy of these disorders.

Biomarkers↗
PubMed2001

Flow cytometric analysis of cytokine production by normal human peripheral blood dendritic cells and monocytes: comparative analysis of different stimuli, secretion-blocking agents and incubation periods.

In this paper, we comparatively analyze the effects of the following different stimuli on the production and intracellular accumulation of the interleukin (IL)-1 beta, IL-6, IL-12, tumor necrosis factor-alpha (TNF-alpha), and IL-8 inflammatory cytokines in both normal human peripheral blood (PB) dendritic cell (DC) subsets and monocytes: lipopolysaccharide (LPS) versus Staphylococcus aureus cowan I (SAC) in the presence or absence of interferon-(IFN)-gamma-, cytokine secretion-blocking agents (brefeldin A alone versus brefeldin A plus monensin), and incubation periods (6, 12, and 24 h). For this purpose, a four-color multiple-staining direct immunofluorescence technique analyzed by flow cytometry was systematically used in all experiments (n = 19). Our results show that after stimulation, an important proportion of each of the two CD33(+) myeloid DC subsets as well as the monocytes produce significant amounts of all cytokines analyzed under each of the experimental conditions assayed. In contrast, CD33(-/+lo) lymphoplasmocytoid DC failed to produce detectable levels of any of the above-mentioned cytokines under the same stimulatory conditions. Upon comparing the different stimuli used, LPS was associated with higher percentages of cytokine-producing cells compared with SAC, especially within the CD33(hi) DC subset; interestingly, the addition of IFN-gamma enhanced the response of monocytes to both LPS and SAC. As regards the secretion-blocking agents, brefeldin A alone was superior to the combination of brefeldin A and monensin. This is because it was frequently associated with both a higher percentage of cytokine-positive cells and greater amounts of detectable cytokines per cell. Sequential analysis of cytokine production by PB DC and monocytes after 6, 12, and 24 h of cell culture showed that after 6 h, an increased cell death rate existed among DC, which became even undetectable at 24 h, in the absence of a significant increase in cytokine secretion. In summary, our results show that from the experimental conditions assayed in this paper, to induce cytokine production by normal human DC and monocytes, maximum response is obtained once PB samples are stimulated for 6 h with LPS (with or without IFN-gamma) in the presence of brefeldin A alone.

Adolescent↗
PubMed2001

Sequential analysis of CD34+ and CD34- cell subsets in peripheral blood and leukapheresis products from breast cancer patients mobilized with SCF plus G-CSF and cyclophosphamide.

Administration of stem cell factor (SCF) has been proven to enhance cytokine-induced mobilization of CD34+ hematopoietic progenitor cells (HPC) into the peripheral blood (PB). The aim of the present study was to explore in a homogeneous group of 22 uniformly treated breast cancer patients: (1) the kinetics of mobilization into PB of both CD34+ and CD34- cell subsets, including dendritic cells, in sequential samples obtained from day +7 up to day +12 after mobilization; and (2) the composition of the CD34+ and CD34- cell subsets present in the two leukapheresis products obtained for each patient. The following CD34+ and CD34- subsets were analyzed: early CD34+ HPC, erythroid-, myeloid- and B-lymphoid-committed CD34+ precursor cells, mature T, B and NK cells, monocytes, neutrophils, eosinophils, basophils, and dendritic cells (DC) including three subsets of lin-/HLADR+DC (CD16+, CD33high and CD123high). Our results show that the absolute number of PB CD34+ HPC progressively increases from day +7 onwards. As far as the CD34- PB leukocyte subsets are concerned, monocytes (CD14+) displayed the earliest recovery after mobilization predicting neutrophil recovery 1 day in advance. The number of CD34+ HPC collected in a single leukapheresis product was always > or = 1.4 x 10(6) cells/kg body weight. No significant changes were observed between the two leukapheresis sessions either as regards their composition in CD34+ HPC subsets or their CD34- leukocyte populations except for a higher ratio of both CD34+ erythroid/CD34+ myeloid HPC (0.35 +/- 0.13 vs 0.30 +/- 0.13; P = 0.04) and neutrophils/monocytes (1.58 +/- 2.1 vs 0.69 +/- 0.27; P = 0.009) found for the first leukapheresis. Interestingly, the overall number of dendritic cells (DC) was higher in the second leukapheresis (1.06 +/- 0.56 vs 1.9 +/- 0.46; P = 0.02) due to a selective increase of the CD16+ antigen-presenting cells. In summary, our results show that the combination of cyclophosphamide, G-CSF and SCF is highly effective for stem cell mobilization, with differences observed in the mobilization kinetics of the different hematopoietic cell subsets analyzed.

Adolescent↗
PubMed2001

Adult precursor B-ALL with BCR/ABL gene rearrangements displays a unique immunophenotype based on the pattern of CD10, CD34, CD13 and CD38 expresssion.

The Philadelphia chromosome (Ph+) reflects a balanced reciprocal translocation between the long arms of chromosomes 9 and 22 [t(9;22)(q34;q11.2] involving the BCR and ABL genes. At present, detection of BCR/ABL gene rearrangements is mandatory in precursor-B-ALL patients at diagnosis for prognostic stratification and treatment decision. In spite of the clinical impact, no screening method, displaying a high sensitive and specificity, is available for the identification of BCR/ABL+ precursor-B-ALL cases. The aim of the present study was to explore the immunophenotypic characteristics of precursor B-ALL cases displaying BCR/ABL gene rearrangements using multiple stainings analyzed by quantitative flow cytometry in order to rapidly (<1 h) identify unique phenotypes associated with this translocation. From the 82 precursor-B-ALL cases included in the study 12 displayed BCR/ABL gene rearragements, all corresponding to adult patients, four of which also displayed DNA aneuploidy. Our results show that BCR/ABL+ precursor B-ALL cases constantly displayed a homogeneous expression of CD10 and CD34 but low and relatively heterogeneous CD38 expression, together with an aberrant reactivity for CD13. In contrast, this unique phenotype was only detected in three out of 70 BCR/ABL cases. Therefore, the combined use of staining patterns for CD34, CD38 and CD13 expression within CD10-positive blast cells is highly suggestive of BCR/ABL gene rearrangements in adults with precursor B-ALL.

Adult↗
PubMed2000

Alcoholic liver cirrhosis is associated with a decreased expression of the CD28 costimulatory molecule, a lower ability of T cells to bind exogenous IL-2, and increased soluble CD8 levels.

Despite the existence of high interleukin (IL)-12 serum levels in patients with chronic active alcoholism, previous studies from our group have shown that, during active ethanol intake, alcoholic patients with alcoholic liver cirrhosis (ALC) display an impaired T-helper-1 response together with abnormalities in the peripheral blood (PB) cytotoxic compartment. The aim of the present study was to gain further insights into the mechanisms underlying these abnormalities. For that purpose, we analyzed the expression on PB B- and T-cell subsets of both the CD28 and CD80 costimulatory molecules, the ability of T lymphocytes to bind to exogenous recombinant IL-2, and the serum levels of soluble CD8 (sCD8) that might interfere with CD8+ T-cell activation in a group of 10 ALC patients with active ethanol intake (ALCET group). As reference groups, we analyzed 10 healthy individuals, 10 chronic alcoholic patients without liver disease (AWLD group) but with active ethanol intake, and 10 ALC patients who had quit drinking for at least 1 year. Our results showed that ALCET patients display a significant decrease in the number of PB CD28+/CD8(hi) T cells (P < 0.05) and CD80+ B cells (P < 0.01) compared with both healthy controls and AWLD patients. In addition, in ALCET patients, PB T cells also showed a decreased ability to bind to exogenous IL-2 (P < 0.01). This was associated with the existence of increased serum levels of sCD8 in ALC patients, the highest levels being detected in the ALCET group (P < 0.01). Altogether, our results point to the existence of several abnormalities that would affect the cytotoxic response in ALCET patients.

Adult↗
PubMed2000

Flow cytometric detection of intracellular myeloperoxidase, CD3 and CD79a. Interaction between monoclonal antibody clones, fluorochromes and sample preparation protocols.

Detection of intracellular myeloperoxidase (MPO), CD79a and CD3 has become the most specific tool for the assignment of myeloid, B- and T-lymphoid lineages in acute leukemias. In order to establish the best combination of monoclonal antibody reagent and sample preparation technique for the intracellular detection of these three markers, we compared six different cell fixation-permeabilization kits (Cytofix/Cytoperm, Fix and Perm, Intraprep, Intrastain, Permeacyte and Permeafix) using 12 fluorochrome conjugates derived from seven monoclonal antibody (mAb) clones. A total of 21 samples corresponding to normal peripheral blood (n=4), normal bone marrow (n=3), acute myeloblastic leukemia (AML, n=6), precursor B-acute lymphoblastic leukemia (ALL, n=6) and T-ALL (n=2) cases, were analysed in two centers. All fixation/permeabilization methods resulted in decreased side scatter and mostly increased forward scatter as compared to erythrocyte-lyse-washed and 1% paraformaldehyde fixed samples. The autofluorescence levels of the leukocyte populations was only significantly increased with use of the Cytofix/Cytoperm kit and mildly with the other techniques. In addition, non-specific staining increased significantly for combinations of any anti-MPO mAb with the Cytofix/Cytoperm kit and for the CD3 clone S4.1 combined with any intracellular method. Anti-MPO antibodies gave a stronger fluorescence signal when conjugated to PE than when coupled to FITC. In conclusion, MPO-7-PE, UCHT-1-PE (CD3) and any HM57-PE conjugate (CD79a) in combination with Fix and Perm, Intraprep, Intrastain or Permeafix, provided specific staining of the respective markers in sufficient intensities. Thus, combined selection of fixation/permeabilization kits and monoclonal antibody reagents against CD3, CD79a and MPO is required for obtaining optimal cytoplasmic detection of these antigens.

Antibodies, Monoclonal↗
PubMed2000

Loss of CD34(+) hematopoietic progenitor cells due to washing can be reduced by the use of fixative-free erythrocyte lysing reagents.

Current protocols for sample preparation before flow cytometric enumeration of CD34(+) hematopoietic progenitor cells (HPC) include both lyse-non-wash and lyse and wash methods. Erythrocyte lysis without washing is the method of choice when absolute cell counts are to be assessed, whilst a washing step is recommended for immunological subtyping of CD34(+) cells in order to reduce background fluorescence. Here, we analyzed the effect of the interaction between type of erythrocyte lysis reagent and washing on the outcomes of (i) CD34(+) cell enumeration and (ii) expression of CD38 by CD34(+) cells in a single-platform, whole-blood staining assay [Gratama, J.W., Keeney, M., Sutherland, D.R., 1999. Enumeration of CD34(+) hematopoietic stem cell and progenitor cells. Curr. Protocols Cytometry 6(4), 1-22.]. We studied seven commercially available lysing reagents (five containing fixative and two fixative-free) using 12 samples from cord blood (n=4), mobilized peripheral blood (n=4) and apheresis products (n=4). Using the lyse and wash technique, significant reductions of absolute and relative numbers of CD34(+) cells, as well as in the numbers of lymphocytes and leukocytes, were observed on samples that had been lysed using fixative-containing buffers as compared to the lyse-no-wash technique. Cell losses due to washing could be significantly reduced when samples were lysed using fixative-free buffers. 'Postfixation' using PBS+1% paraformaldehyde of samples that had been lysed using fixative-free buffers and then washed did not result in additional loss of CD34(+) cells or other cell types. Finally, washing unfixed samples led to a slight decrease of CD38 monoclonal antibody bound to CD34(+) cells as compared to samples that had been fixed during erythrocyte lysis. These results indicate that fixation renders (CD34(+)) cells sticky and leads to their loss from the cell suspension upon centrifugation and resuspension. We conclude that all seven lysing reagents can be used with confidence in a lyse-no-wash technique, but that only fixative-free lysing reagents should be used when a washing step is considered necessary.

Antigens, CD34↗
PubMed2000

A new method for the simultaneous analysis of growth and death of immunophenotypically defined cells in culture.

BACKGROUND: Internal standards have been used in flow cytometry methods to enumerate lymphoid subsets and hemopoietic progenitor cells ex vivo. However, the currently available methods cannot be readily applied to the analysis of cultured cells because of the frequent occurrence of cell death during in vitro assays. METHODS: This paper reports a new method for the enumeration of both viable and nonviable cells in culture. Cells were counted with the aid of an internal reference standard of microbeads, and live versus dead cell discrimination was performed using 7-amino-actinomycin D which allows the double staining of surface antigens. RESULTS: The method is more precise, accurate and sensitive than either conventional light microscopy-based or automated cell counting. Additionally, it may be used to accurately measure the number of apoptotic cells in a culture. RESULTS: Through the enumeration of surviving cells it is demonstrated that, when applied to the study of mitogen-activated T lymphocytes, current flow cytometry techniques (which do not use internal standards) for the study of the viability and apoptosis overestimate the fraction of viable cells and underestimate both the fraction of dead and apoptotic cells. CONCLUSIONS: The new method overcomes these limitations and is of use in the in vitro study of cell growth and apoptosis.

Apoptosis↗
PubMed2000

Expression of high amounts of the CD117 molecule in a case of B-cell non-Hodgkin's lymphoma carrying the t(14:18) translocation.

The c-kit proto-oncogen (CD117) has been described to be present in normal and neoplastic hemopoietic cells including both myeloid and lymphoid lineages. Among the normal lymphoid cells CD117 expression would be restricted to a small subset of NK-cells, and to early T-cell precursors and it is not expressed by normal B-cells. Regarding chronic lymphoproliferative disorders the only data provided up to now suggests that CD117 expression is restricted to cases of Hodgkin's disease and anaplastic large-cell lymphoma. In the present paper we describe a case of a B-cell chronic lymphoproliferative disorder carrying the t(14:18) translocation as demonstrated by molecular studies, in which the flow cytometric immunophenotypic analysis of both peripheral blood and bone marrow samples revealed the expression of high amounts of the CD117 antigen in the surface of the clonal B-cell population. Further studies are necessary to explore both the functional role of c-kit expression in the neoplastic B-cells from this patient and its potential utility for the diagnosis and follow-up of patients with B-cell non-Hodgkin's lymphoma.

Aged↗
PubMed2000

Cell-cycle distribution of pancreatic cells from rats with acute pancreatitis induced by bile-pancreatic obstruction.

The aim of this study was to analyze, using electron microscopy, the morphological alterations that progressively appear in the pancreas of rats with acute pancreatitis induced by bile-pancreatic obstruction over 48 h. In addition, in order to ascertain the capability of pancreas regeneration at different stages of pancreatitis, the distribution of pancreatic cells throughout the different phases of the cell cycle was also analyzed by flow cytometry using propidium iodide staining. Interstitial edema, macrophage infiltration, vacuolization, and dilatation of endoplasmic reticulum were observed from 1.5 h after obstruction onward. Interestingly, cell cycle studies showed an increased proportion of S-phase cells at early stages of pancreatitis (1.5 h after obstruction), which leads to a significant increase in cells in G2/M phase 12 h after pancreatic obstruction. Histological studies revealed severe alterations in pancreas of rats with obstruction maintained over 48 h which affects the nuclear structure. Intracellular disorganization, apoptosis, and focal necrosis were observed at this stage. Furthermore, flow-cytometric analysis of cell DNA contents showed a significant decrease in the proportion of S and G2/M cells and a significant increase in G0/G1 cells, suggesting an arrest of almost all cells in quiescent states. These results suggest that rat pancreas cells are able to recover during the first 12 h after pancreatic obstruction. However, the gland would lose its ability to regenerate if the obstruction was maintained for longer periods.

Acute Disease↗
PubMed2000

BIOMED-1 concerted action report: flow cytometric characterization of CD7+ cell subsets in normal bone marrow as a basis for the diagnosis and follow-up of T cell acute lymphoblastic leukemia (T-ALL).

The European BIOMED-1 Concerted Action was initiated in 1994 to improve and standardize the flow cytometric detection of minimal residual disease (MRD) in acute leukemia (AL). Three different protocols were defined to identify the normal subsets of B, T and myeloid cells in bone marrow (BM), and were applied to the different types of AL in order to study aberrant immunophenotypes. Using sensitive acquisition methods ('live gate') T cell subsets in normal BM could be identified with five triple-stains: CD7/CD5/CD3, CD7/CD4/CD8, CD7/CD2/CD3, CD7/CD38/CD34 and TdT/CD7/surface or cytoplasmic (cy)CD3 (antibodies conjugated with FITC/PE/PECy5 or PerCP, respectively). The identification of T cell subsets in BM allowed definition of 'empty spaces' (ie areas of flow cytometric plots where normally no cells are found). All studied T-ALL cases (n = 65) were located in 'empty spaces' and could be discriminated from normal T cells. The most informative triple staining was TdT/CD7/cyCD3, which was aberrant in 91% of T-ALL cases. In most cases, two or more aberrant patterns were found. Apparently the immunophenotypes of T-ALL differ significantly from normal BM T cells. This is mostly caused by their thymocytic origin, but also the neoplastic transformation might have affected antigen expression patterns. Application of the five proposed marker combinations in T-ALL contributes to standardized detection of MRD, since cells persistent or reappearing in the 'empty spaces' can be easily identified in follow-up BM samples during and after treatment.

Antigens, CD↗
PubMed2000

Quantitative multiparametric immunophenotyping in acute lymphoblastic leukemia: correlation with specific genotype. I. ETV6/AML1 ALLs identification.

The t(12;21)(p13;q22) fusion gene is the most frequent genetic lesion described in precursor B cell acute lymphoblastic leukemia (ALL) of childhood occurring in a quarter of cases. This gene rearrangement is associated with a good outcome presenting a high response rate to chemotherapy. In spite of its potential clinical relevance, the t(12;21) translocation usually goes undetected with conventional cytogenetic procedures. In the present study we utilized an objective flow cytometric approach (multiparametric quantitative analysis) for the phenotypic characterization of this type of ALL. We studied a total of 74 precursor B-ALL children, including 21 t(12;21)+ and 53 t(12;21)- cases. Our results show that the t(12;21)(p13;q22)+ ALLs display a higher intensity of CD10 (P = 0.0016) and HLADR (P = 0.005) expression together with lower levels of the CD20 (P = 0.01), CD45 (P = 0.01), CD135 (P = 0.003) and CD34 (P = 0.03) antigens as compared to the t(12;21) cases. Moreover, as regards CD34 expression, we observed a more heterogeneous antigen expression within individual patients with higher coefficients of variation (median of 202 vs 88, P = 0.0001). A multi-variate analysis disclosed that with the immunophenotypic approach used identification of t(12;21)+ cases can be achieved with a sensitivity of 86% and a specificity of 100%. We conclude that childhood precursor B-ALL carrying the t(12;21) translocation display characteristic phenotypic features which could provide a rapid, simple, sensitive and specific screening method to select for those cases that should undergo confirmatory molecular analysis.

Antigens, CD↗
PubMed2000

Alterations in the glycoconjugates of pancreatic cell membrane induced by acute pancreatitis.

The alterations that progressively appear in plasma membrane glycoconjugates of rat pancreatic cells at different stages of acute pancreatitis induced by duct obstruction have been analyzed on individual cells by flow cytometry using the fluoresceinated lectins, wheat germ agglutinin (WGA), Tetragonolobus purpureus agglutinin (TP) and Concanavalin A (Con A), which specifically bind to N-acetyl D-glucosamine, L-fucose and D-mannose, respectively. Two populations of pancreatic cells were differentiated according to the forward scatter (size), which showed different density of saccharidic terminals located at external positions in the glycoconjugates of the plasma membrane. A significant increase in WGA and TP binding was found 1.5 h after pancreatic obstruction, which could be due to the fusion of zymogen granules with the plasma membrane as suggested by the basolateral exocytosis observed by electron microscopy at this stage. The most external sugar residues of membrane glycoconjugates are removed 12 h after pancreatic duct obstruction as a consequence of an advanced state of pancreatitis. The hydrolytic process reaches greater depths in the membrane 48 h after obstruction. At this stage a significant decrease in WGA, TP and ConA binding was found in all pancreatic cells, indicating the loss of N-acetyl D-glucosamine and/or sialic acid, L-fucose and even D-mannose which is located in the core of the glycan. The results provide information about the progressive degradation induced by acute pancreatitis in pancreatic cell membrane glycoconjugates.

Acute Disease↗
PubMed2000

Two new 3' PML breakpoints in t(15;17)(q22;q21)-positive acute promyelocytic leukemia.

In the present article, two new types of PML/RARA junctions are described. Both were identified in diagnostic samples from two t(15;17)(q22;q21)-positive acute promyelocytic leukemia (APL) patients who failed to achieve complete remission. By using different sets of primers, reverse transcriptase polymerase chain reaction (RT-PCR) of PML/RARA junctions showed atypical larger bands compared with those generated from the three classical PML breakpoints already described. Sequence analysis of the fusion region of the amplified cDNAs allowed us to determine the specificity of these fragments in both patients. This analysis showed two new hybrid transcripts that were 53 and 306 base pairs (bp) longer than that expressed by the NB4 cell line (PML breakpoint within intron 6), and are the result of the direct joining of RARA exon 3 with PML exon 7a (patient 2) or the 5' portion of PML exon 7b (patient 1), respectively. In patient 1, RT-PCR analysis of the reciprocal RARA/PML junction showed a smaller transcript than that expected in bcr1 cases, while in patient 2 no amplified fragment was obtained. Cytogenetic analysis and/or fluorescence in situ hybridization (FISH) showed that both patients had the t(15;17) translocation. The clinical and hematological profiles expressed by the two patients carrying these unexpected types of PML/RARA rearrangement did not differ significantly from that commonly seen in other APLs with the exception of the poor outcome. Genes Chromosomes Cancer 27:35-43, 2000.

Adult↗
PubMed2000

Enzyme load in pancreatic acinar cells is increased in the early stages of acute pancreatitis induced by duct obstruction in rats.

Trypsinogen and amylase content has been analysed by flow cytometry in individual pancreatic cells from rats with acute pancreatitis induced by pancreatic duct obstruction, from the earliest stages to 48 h after obstruction. Parallel morphological studies of the pancreas by electron microscopy and analysis of various parameters for the diagnosis of pancreatitis will allow research into the possible relationship between intracellular enzyme load and the severity of pancreatitis. Progressive increases in amylase activity in ascites and plasma, the volume of ascites, haematocrit, vacuolization, oedema and macrophage infiltration were observed between 1.5 h and 12 h after duct obstruction. A progressive increase in enzyme content was also observed in individual acinar cells at this stage. Interestingly, the larger increase was for trypsinogen, so that the trypsinogen/amylase ratio was significantly increased in all acinar cells by 12 h after duct obstruction. This represents a risk factor for the development of pancreatitis. Sections of pancreas taken from rats that had duct obstruction for 48 h showed massive dilatation and disorganization of the endoplasmic reticulum, focal apoptosis and necrosis. These severe alterations would affect enzyme synthesis, as reflected by the significant decrease in the intracellular enzyme load observed at this stage. However, not all acinar cells were affected equally by the damage induced by pancreatitis: R(1) cells appeared to be more sensitive than R(2) cells. In conclusion, intracellular accumulation of digestive enzymes occurs at early stages of pancreatitis, and this effect is proportionally greater for trypsinogen, a finding that could explain the degree of severity achieved in the course of pancreatitis.

Acute Disease↗
PubMed1999

Enumeration of CD4(+) T-cells in the peripheral blood of HIV-infected patients: an interlaboratory study of the FACSCount system.

The aim of the present study was to assess the interlaboratory reproducibility of the FACSCount system for the enumeration of peripheral blood (PB) CD4(+) T-cells. In each of the seven participating centers, both previously stained and unstained PB samples (n = 49) were received and either analyzed or stained and then analyzed. Interlaboratory reproducibility was checked in two different groups of centers (n = 3 and n = 4) where the study was performed in parallel. In addition, both the intralaboratory precision and accuracy of this system were analyzed in comparison with results obtained with conventional flow cytometry. Accordingly, upon comparing both methods, a high degree of correlation was observed in the total number of CD3(+) T-cells (coefficient of correlation of 0.9750 +/- 0.0184, slope of the best linear fit: 0. 9214 +/- 0.0311, y-intercept of 12 +/- 47) as well as in the number of CD3(+)/CD4(+) (coefficient of correlation of 0.9794 +/- 0.1457, slope of the best linear fit: 0.9463 +/- 0.0753, y-intercept of -11 +/- 36) and CD3(+)/CD8(+) (coefficient of correlation of 0.9728 +/- 0.0192, slope of the best linear fit: 0.9682 +/- 0.0735, y-intercept of 7 +/- 95) major subsets. In addition, low coefficients of variation (CV) were obtained for replicates, indicating the method's high degree of accuracy. The present study shows that with respect to the interlaboratory reproducibility reported for most techniques used for the enumeration of PB CD4(+) T-cells, the FACSCount system results in data with much lower coefficients of variance (CVs) (mean CV of less than 10%). Upon measuring the impact on results of different variables associated with either sample preparation or data acquisition and analysis, our study clearly shows that data acquisition and analysis does not influence the results by increasing variability since the coefficients of variation obtained for samples prepared in the same laboratory under the same conditions and read in different laboratories with different instruments were identical to those obtained for the replicates of the same samples read in each individual center. In contrast, interlaboratory variability, although low, significantly increased when sample preparation was carried out in different laboratories, suggesting that pipetting still represents the major source of variability in the FACSCount system.

CD4 Lymphocyte Count↗