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Biomedical subjects

A Latorraca

Publications and source records attributed to A Latorraca.

At least 19 recordsLinked to original sources
PubMed2000

An apparent outbreak of cutaneous papillomatosis in merino sheep in patagonia, Argentina.

A retrospective study was performed on skin samples from an outbreak of cutaneous papillomatosis in Merino sheep that occurred in 1995. The samples were processed for routine histology, electron microscopy and immunocytochemistry for papilloma viruses. Particles of approximately 55 nm diameter were found in some nuclei of the stratum granulosum cells, while immunocytochemistry gave positive staining of cell nuclei in this layer. This study confirms that papillomas associated with papillomaviruses occur in sheep in Patagonia.

Animals↗
PubMed2000

Prolonged remission state of refractory adult onset Still's disease following CD34-selected autologous peripheral blood stem cell transplantation.

We report a 38-year-old patient affected by refractory adult onset Still's disease who achieved a prolonged remission following CD34-selected ABMT. The conditioning regimen was based on the use of CY and anti-thymocyte globulin. A 3.0 and 2.0 log reduction of T (CD3+) and B (CD19+) lymphocytes, respectively, was obtained using a Ceprate device to select CD34+ cells from PBSC. In the pre-transplant period (1994-1998) the patient had a chronic persistent disease course with frequent and recurrent systemic articular flares and loss of some functional abilities, despite daily prednisone, pulses of CY and immunosuppressive therapy (CYA or MTX). At the time of ABMT the patient had become non-ambulatory. Within 3 weeks of ABMT the patient showed a marked decrease in joint swelling, and morning stiffness. Joint pain and systemic symptoms disappeared, the patient was able to walk and run and gained general well being. ESR, C-reactive protein and WBC count were significantly decreased, while Hb level increased. This partial remission persisted for at least 1 year after ABMT, although at 15 months of follow-up a reappearance of moderate synovitis in the knees and wrists was noted. Our data further showed that both patient BM microenvironment and stem-progenitor cell function (as assessed by LTC-IC assay) were damaged even 1 year after CD34-selected ABMT, suggesting that the persistence of these alterations could have facilitated the favorable outcome of the disease following ABMT. Bone Marrow Transplantation (2000) 25, 1307-1310.

Adult↗
PubMed1999

Assessment of distribution of CD34 epitope classes in fresh and cryopreserved peripheral blood progenitor cells and acute myeloid leukemic blasts.

BACKGROUND AND OBJECTIVE: So far several reports have described changes in the expression of surface antigens in progenitor cells and blasts following cryopreservation. However, there are no data on the effects of cryopreservation on the expression of the three CD34 epitope classes, and on their relationship with the clonogenic capacity of PBPC collected by leukapheresis. DESIGN AND METHODS: In order to analyze the effects of freezing/thawing procedures (Eth 80C storage for 3 months) and use of dimethylsulfoxide (DMSO) on the immunophenotype profile and colony production of peripheral blood progenitor cells (PBPC) in apheresis products derived from 20 patients with stage 0-III non-Hodgkin's lymphoma (nHL), a flow cytometry study was undertaken using different CD34 monoclonal antibodies (MoAbs) capable of recognizing the 3 epitope classes of CD34 molecule (class III: HPCA-2/FITC, HPCA-2/PE, 581/FITC, 581/PE; class II: Q-Bend 10/PE; class I: ICH3/PE, BI3C5-PE, Immu-133-PE). CD34 epitope expression was also analyzed in thawed CD34+ blasts obtained from 14 patients with acute myeloid leukemia (AML), who were analyzed using a larger number (#17) of CD34 epitope class I, II, and III reactive MoAbs. RESULTS: Under our experimental conditions it was found that class III and class II CD34 epitopes (differentially resistant to enzymatic cleavage with neuraminidase, chymopapain and glycoprotease) are better preserved than class I epitope Eth sensitive to degradation Eth after cell exposure to cryoprotectant DMSO and the freezing- thawing procedures. Results further showed a concomitant decrease in class I CD34+ counts and in BFU-E colony production. A significant increase in CD34 antigen expression levels (i.e. antibody binding capacity, ABC) by cryopreserved cells stained with CD34 epitope class III, and class II reactive MoAbs was also documented, while no changes after cryopreservation were noted using class I-reactive MoAbs. The slight increase in the percentage of CD34+ cells detected after frozen storage was correlated to a concomitant decrease in the number of more mature myeloid cells (CD15+, CD13+, CD33+). Compared to pre-cryopreservation values, a slight reduction in class I CD34 epitope expression was also found in thawed CD34+ AML blasts. INTERPRETATION AND CONCLUSIONS: As far as the reduction of class I CD34 epitope is concerned, it may be hypothesized that the freezing procedure, use of DMSO, and/or lysis methodology may either damage a CD34 subset, or induce distinct alterations of the CD34 glycoprotein, possibly determining a reduction in their immunoreactivity with some CD34 MoAbs. In conclusion, this study has shown that exposure to the cryoprotectant DMSO and the freezing/thawing procedures modifies the distribution of CD34 epitopes as well as the clonogenic capacity of PBPCs from nHL patients, and CD34+ blasts from AML. These findings need to considered when selecting CD34 MoAbs for enumeration and positive selection of stem/progenitor cells for research and clinical purposes.

Acute Disease↗
PubMed1998

Expression and functional role of urokinase-type plasminogen activator receptor in normal and acute leukaemic cells.

Urokinase-type plasminogen activator receptor (UPA-R-CD87) is a GPI-anchored membrane protein which promotes the generation of plasmin on the surface of many cell types, probably facilitating cellular extravasation and tissue invasion. A flow cytometric quantitative analysis of expression levels for UPA-R was performed on fresh blast cells from patients with acute myeloid leukaemia (AML, n = 74), acute lymphoblastic leukaemia (ALL, n = 24), and biphenotypic leukaemia (BAL, n = 3) using two CD87 monoclonal antibodies (McAbs) (3B10 and VIM5). Peripheral blood and bone marrow (BM) cells from 15 healthy adults served as controls. Using 3B10 McAb, UPA-R was expressed (>99%) by blood monocytes, neutrophils, and BM myelomonocytic precursors in controls, whereas resting T and B lymphocytes, and CD34+ cells were UPA-R negative. We also attempted to clarify whether UPA-R has a role in mediating neutrophil functions. Oriented locomotion induced by different chemotaxins and lysozyme release by granules stimulated with fMLP or PMA were significantly decreased when UPA-R was neutralized by CD87 McAb. In contrast, the anti-UPA-R McAb had no effect on superoxide anion generation of normal neutrophils. Blasts from AML showed a heterogenous pattern of expression for the UPA-R McAbs, with reactivity strictly dependent on FAB subtype. The highest UPA-R expression was seen in the M5 group: all patients tested (n = 20) showed strong positivity for the UPA-R McAb whereas only 12% (3/24) of ALL patients were CD87 positive, and 2/3 of BAL patients showed a dim expression for CD87. The number of receptors expressed by blast cells in 6/74 (8.1%) AML patients was higher than those of normal samples: in addition, since co-expression of UPA-R and CD34 was not found in normal haemopoietic cells, it may be postulated that CD87 can be used alone (when overexpressed) or in combination with CD34 for the detection of minimal residual disease. Results also indicated that patients with UPA-receptors >12 x 10(3) ABC/cell, irrespective of FAB subtype, had a greater tendency for cutaneous and tissue infiltration and a higher frequency of chromosome abnormalities, thus suggesting the concept that cellular UPA-R content positively correlates with the invasive potential of AML cells. The combination of higher UPA-R positivity, abnormalities of chromosome 11, and M5 FAB morphology may identify a peculiar subset of AML, characterized by a more aggressive clinical course.

Acute Disease↗
PubMed1997

Comparative analysis of different permeabilization methods for the flow cytometry measurement of cytoplasmic myeloperoxidase and lysozyme in normal and leukemic cells.

Using a direct one-color (fluorescein isothiocyanate; FITC) staining method with a Facscan flow cytometer, we evaluated the intracellular expression of two granular constituents of myeloid cells [myeloperoxidase (MPO) and lysozyme] on leukemic cells from 21 patients with acute myeloid leukemia (AML), and 6 patients with acute lymphoblastic leukemia (ALL). Three different permeabilization techniques were used [FACS Lysing Solution (FLy), B.Dis; Ortho-PermeaFix (OPF); Fix and Perm (F&P), Caltag] prior to monoclonal antibody (McAb) staining, in order to verify the specificity and the sensitivity of the three labelling methods towards the two model antigens. Peripheral blood cells from 15 healthy subjects and Ortho Absolute Control served as controls. Data were expressed as percentage of positivity, net fluorescence intensity, ratio between mean fluorescence intensity (MFI) of positive cells and that of isotypic controls (P/N ratio; evaluated in both geometric and arithmetic scale), and, in 12 representatives cases (7 AML, 5 normal samples), in the form of both molecules of equivalent soluble fluorochromes (MESF) and antibody binding capacities (ABC). As far as the antigenic expression of MPO and lysozyme in normal samples is concerned, F&P resulted, in our hands, in the most specific and sensitive staining, followed by FLy solution and OPF, which showed positivity for MPO, and, to lesser extent, for lysozyme in a considerable manner of lymphocytes (means 64% and 54%, respectively, for OPF and FLy; range of ABC/cell: 0.9-5.2 x 10(3)) obtained from healthy subjects. With the reference F&P permeabilizing solution, 90% and 80% of FAB M1-M5 cases were found to be positive for MPO and lysozyme, respectively. However, M1, M2, and M3 AML FAB (French-American-British) subvarieties were characterized by a brighter expression for MPO (mean ABC/cell: 89 x 10(3)) than that of lysozyme (mean ABC/cell: 12.5 x 10(3D)), whereas blast cells from patients with M5a FAB subtypes showed higher levels of lysozyme (mean ABC/cell: 65 x 10(3)) than that of MPO (mean ABC/cell: 0.1 x 10(3)). One of five cases of FAB MO AML showed a dull positivity for MPO-7 McAb. Patients with ALL were MPO and lysozyme negative using both F&P and FLy reagents, although a certain degree of positivity was documented in some cases with OPF. Taking these data together, it can be stated that the use of anti-MPO McAbs may be of great value for the diagnosis and monitoring of acute leukemia and, along with lysozyme McAb, can provide useful information in the distinction of myeloid from monocytic leukemias and in the lineage assignment of apparently biphenotypic forms. However, the methodology used for the detection of these myeloid-associated antigens is critical for a correct interpretation of cytofluorimetric data and should be taken into account when evaluating data coming from multicenter trials dealing with leukemias. A standardization of cytofluorimetric analysis of intracellular antigens is needed in order to improve the reproducibility and comparability of results in multicenter studies.

Adult↗
PubMed1997

Flow cytometry measurement of GM-CSF receptors in acute leukemic blasts, and normal hemopoietic cells.

A quantitative analysis of expression levels of GM-CSF receptors was performed by flow cytometry in different disease categories, ie AML (n = 72), ALL (n = 18), and MDS (n = 12), as well as 12 healthy volunteers, using three different unconjugated GM-CSF/R monoclonal antibodies (McAbs) (HGM-CSFR (CD116), M5D12, 4B5F5), and appropriate standards. By using the reference HGM-CSFR McAb, in healthy subjects we found detectable levels of GM-CSF/R on blood monocytes (mean MESF (molecules of equivalent soluble fluorochrome)/cell: 36.1 x 10[3]), neutrophils (mean MESF/cell: 7.4 x 10[3]), bone marrow (BM) myelo-monocytic precursors (MESF range for the myeloid component, ie promyelocytes, myelocytes, metamyelocytes: 11.7-40.5 x 10[3], and for the monocytic lineage: 25.7-69.2 x 10[3]), and in two distinct subsets of BM CD34+ progenitor cells (GM-CSF/R dim: 2.5 x 10[3] MESF/cell, GM-CSF/R bright (10% of the total number of CD34 cells: 22.0 x 10[3] MESF/cell). In these subjects, there was no correlation between the expression levels of GM-CSF/R and CFU (CFU-GM, CFU-GEMM, BFU-E) colony production. Among the AML samples, M5D12 McAb was positive in 33%, 4B5F5 McAb in 90%, and HGM-CSF/R McAb in 78% of the cases examined (range of MESF/cell for the HGM-CSFR McAb: 0.9 x 10[3]-106.7 x 10[3]). The highest MESF values were seen in the M5 FAB subvariety (mean: 39.4 x 10[3]), where all the patients tested (n = 20) showed a strong positivity for the HGM-CSFR McAb. On the contrary, all ALL samples were GM-CSF/R negative except in two patients, who displayed a dim GM-CSF/R positivity (My+ALL: 1.3 x 10[3] MESF/cell; pro-B ALL: 1.0 x 10[3] MESF/cell). In most (>70%) M1 FAB subtypes, GM-CSF/R+ blasts co-expressed CD34low, HLA-DRhigh, CD33, CD38 antigens, and had little or no capacity to form CFU-GM colonies. GM-CSF/R+ blasts from the M5 FAB category were also positive for CD14, CD11c, CD33 and CD87. Furthermore, the number of GM-CSF/R expressed by leukemic cells from five out of 72 (7%) AML patients was above the highest values seen in normal samples (>69.2 x 10[3] MESF/cell), allowing the possibility of using this marker for the monitoring of the minimal residual disease (MRD) in a subset of AML. Cell culture studies aimed at evaluating GM-CSF receptor modulation following AML blast exposure to rhGM-CSF showed two distinct patterns of response; in the first group (6/10 cases) rhGM-CSF down-modulated GM-CSF receptors, whereas in the second group (4/10 cases), rhGM-CSF treatment was associated with either an increase or no change in the number of GM-CSF/R. In conclusion, cellular GM-CSF/R expression was variable and ranged from undetectable (ALL and a minority of AML) to very high intensities in M5 AML, and were also documented in some M0 AML, thus suggesting the concept that GM-CSF/R detection may be of help in lineage assignment of undifferentiated forms. Since the number of GM-CSF/R on AML blasts may be modulated after GM-CSF treatment, it can be postulated that the clinical use of GM-CSF in this disease may be optimized by a dynamic analysis of the number and the affinity status of GM-CSF-R in blasts and normal hemopoietic cells.

Acute Disease↗
PubMed1996

p53 exon 5 mutations in two cases of leukemic mantle cell lymphoma.

Although p53 mutations have been described frequently in high-grade B-cell non-Hodgkin's lymphoma (NHL), they have only been reported occasionally in low-grade NHL. We therefore describe clincobiologic and molecular genetic findings in two patients with p53 mutations and leukemic mantle cell lymphoma featuring an unusually aggressive course. Circulating malignant cells showed irregularity of nuclear outline with frequent deep clefts in both cases. Immunologic studies of neoplastic cells from peripheral blood samples and from cells obtained from an involved lymph node showed a mantle B-cell phenotype (CD5+, CD19+, CD22+, CD23- or weakly+ and bright expression for surface immunoglobulins). Malignant cells were shown to be hyperdiploid by cytofluorimetric study of DNA content and the presence of the t(11;14)(q13q32) was documented in one case. An altered electrophoretic mobility of p53 exon 5 was seen in both cases, with a missense mutation at codon 158 present in one case and a CAG to TAG mutation resulting in a 167-stop codon present in the second case. The percent of reactive cells with the 1801 monoclonal antibody detecting an epitope of the p53 was 37% in one case and 1% in the second case, supporting the notion that immunologic overexpression cannot be used for a selection criterion for the detection of p53 mutations. From these findings and from data available in the literature the conclusion can be drawn that p53 gene mutations at codons 158 and 167 may be associated with lymphoproliferative disorders and that low- or intermediate-grade NHL, including leukemic mantle cell lymphoma, may frequently carry this genetic change.

Aged↗
PubMed1995

Reduced bone mass and normal calcium metabolism in systemic sclerosis with and without calcinosis.

Forty-three female patients with systemic sclerosis divided into subgroups based on the extent of skin involvement and the presence of calcinosis, and 50 sex and age-matched healthy controls were investigated for bone mineral density (BMD) on the basis of radial (dual photon absorptiometry, Osteograph, NIM), lumbar, and total body measurements (dual energy X-ray absorptiometry, Lunar DPX, Lunar Corp.), and for parameters of calcium metabolism. The patients showed a lower BMD (mean +/- SD; mg/cm2) than the controls at the radial (313 +/- 69 vs 347 +/- 73; p < 0.005), lumbar (974 +/- 143 vs 1081 +/- 154; p < 0.005), and total body (997 +/- 82 vs 1075 +/- 109; p < 0.05) determinations. The patients with the diffuse form of skin involvement had lower values than those with the limited form. There was a negative correlation between BMD and the duration of the disease. The presence of calcinosis was not found to have any effect on BMD. Calcium metabolism was found to be normal in each subgroup. It may be concluded that generalized osteoporosis is a feature of systemic sclerosis, with and without calcinosis. The extent and duration of the disease may play a role in determining bone loss.

Absorptiometry, Photon↗
PubMed1995

CD34+ leukemic cells assessed by different CD34 monoclonal antibodies.

CD34 monoclonal antibodies (McAbs) are widely used to identify and isolate hemopoietic progenitors and to classify acute and chronic leukemias. We assessed the reactivity of 17 CD34 McAbs from the 5th International Workshop on Leukocyte Differentiation Antigens with a variety of cells types: normal bone marrow hemopoietic progenitors, 10 AML, 6 ALL, 11 CML. The reactivity for these McAbs was compared with that of reference CD34 McAbs (Q-Bend 10 and 8G12). For each cell population the % of McAb binding cells, the peak channel and the mean fluorescence intensity (MFI) of the positive cells was evaluated. The peak channel, the MFI and the number of positive cells varied significantly from case to case, depending on the McAb and the type of leukemia. According to the spectrum of reactivity three groups of McAbs were defined; however, 7 McAbs do not belong to any of these subgroups. These groups were not entirely in accordance with McAb classification based on enzyme cleavage that identified three epitopes of the CD34 molecule. Some reagents were found to be more specific for AML, other for ALL, CML or normal CD34+ cells. Normal bone marrow light density cells showed a significantly higher percentage of positive cells for 43A1 and MD34.2 McAbs compared to that documented for the remaining McAbs. AML cells showed the most variable pattern of expression for the CD34 McAbs. In leukemic samples, MESF (molecular equivalents of soluble fluorochrome) values ranged from 18,200 to 322,000 and the number of binding sites per cells was 5,000-81,000.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1994

Neutrophils from patients with myelodysplastic syndromes: relationship between impairment of granular contents, complement receptors, functional activities and disease status.

Myelodysplastic syndromes (MDS) are stem cell disorders of clonal origin in which infections and leukemic transformation are quite frequent. Neutrophils from 28 patients with MDS were analysed by flow cytometry for the expression of the two complement receptors CR1 and CR3, the antigenic reactivity of some granule constituents--myeloperoxidase, lysozyme, elastase, lactoferrin--and functional activities, such as locomotion, respiratory burst and cytotoxicity. The results were correlated with the FAB disease subtypes, grouped as low risk (RA) and high risk patients (RAEB, RAEB-t, CMML) and with 30 healthy subjects. A significant reduction in the percentage of neutrophil CR1, CR3 positivity and chemotaxis induced by endotoxin-activated serum was detected in the high risk group when compared with the low risk group and healthy controls. Furthermore, the high risk group also showed a low amount of myeloperoxidase, elastase, lysozyme and superoxide anion, but both low and high risk groups displayed reduced cellular cytotoxicity in comparison with the control. This work indicates that MDS patients belonging to the more advanced FAB categories frequently show multiple abnormalities in the expression of neutrophil complement receptors, and granular components (> 3), as well as in cell functions, suggesting the possibility of using these phenotypic abnormalities in the monitoring of disease progression.

Chemotaxis, Leukocyte↗
PubMed1994

Trisomy 12 in chronic lymphocytic leukemia and hairy cell leukemia: a cytogenetic and interphase cytogenetic study.

Fluorescent in situ hybridization (FISH) with a chromosome 12-specific pericentromeric probe was performed in 42 patients with B-cell chronic lymphocytic leukemia (CLL) and in 10 patients with hairy cell leukemia (HCL). In all cases, a normal karyotype in more than 10 metaphase cells was obtained by conventional chromosome study. FISH documented that 6/42 patients with CLL in fact had trisomy 12 in 15-49% interphase cells. Sequential FISH studies were performed in 2 cases, showing an increase of percentage of trisomic cells over a 2-month to 4-year period. Two out of 10 patients with HCL, one of whom had morphologic features consistent with a diagnosis of HCL variant, showed 5.5 and 10% interphase nuclei with three fluorescent signals, a finding suggestive of the presence of trisomy 12. Combined immunophenotyping and FISH staining in these patients with HCL documented that trisomic cells were CD11c-positive, CD13-negative, and CD2-negative. We conclude that FISH is a sensitive technique allowing for the detection of trisomy 12 in a fraction of cytogenetically normal patients affected with CLL and HCL.

Aged↗
PubMed1994

Prognostic value of immunophenotypic characteristics of blast cells in acute myeloid leukemia.

In order to elucidate the prognostic role of cytofluorimetry analysis of leukemic cells in AML, the immunophenotypic characteristics of blast cells obtained from 66 AML patients belonging to M0-M2 and M4-M5 FAB subtypes have been investigated by flow cytometry using a large panel of monoclonal antibodies (McAbs) utilized in single, double, and triple fluorescence experiments. On a univariate analysis, four different immunophenotypic blast cell characteristics were found to be associated with a poor prognosis: expression of CD34 "bright" (ratio > 10 between fluorescence emission of positive cells and that of negative (isotypic) control-P/N ratio: mean MESF value: 265,000) in > 15% blast cells, co-expression of CD34 and CD33 in > 60% blast cells, expression of CD14 in > 30% leukemic cells, the MDR+ ("multiple drug resistant") phenotype. In contrast, the duration of remission, and overall survival of AML patients showing a "dim" CD34 expression (P/N ratio: 3-10: mean MESF value: 49,000) was similar to that of CD34- AML patients, irrespective of the percentage of positivity for CD34, which was, however, a predictive factor of survival in patients with higher CD34 fluorescence intensities in their blastic population. No correlation between FAB subtypes, prognosis and immunophenotype was found. The multivariate regression analysis showed that, besides age, only the combined expression of CD34 and CD33 had independent prognostic meaning. Indeed, in each FAB subtypes the CD34+/CD33+ phenotype was associated with a shorter survival and a lower mitotic rate. These data may contribute to the understanding of the discrepancies so far observed in the literature regarding the prognostic role played by the CD34 expression on leukemic AML blasts.

Antigens, CD↗