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Biomedical subjects

A Orfao

Publications and source records attributed to A Orfao.

At least 181 records · Page 10Linked to original sources
PubMed1993

Changes in mitochondrial rhodamine-123-fluorescence populations of rat hepatocytes in primary culture.

Flow cytometry analysis of mitochondria isolated from rat hepatocytes at different stages of development revealed two different rhodamine-123-stained fluorescence populations distinguishable by their main fluorescence channel. The high-fluorescence population (HFP) was minor, accounting for about 32, 33, and 23% of the total mitochondrial fraction in hepatocytes from preterm, term, and early (1 h) newborn rats, respectively. The percentage of HFP decreased during the first 20 h of hepatocytes in culture from preterm and term fetuses but not those from early newborns, in which the decrease occurred during the second day of culture. However, after 20 h in culture more than 80% of hepatocytes reached the G0/G1 phase, whatever the stage of development in which they were sown. This suggests that the observed changes in the fluorescence populations are not associated with the cell cycle; instead these changes mimic those observed during postnatal development and are therefore presumably due to mitochondrial differentiation.

Animals↗
PubMed1993

Immunological features of sporadic multinodular goiter.

The origin of sporadic multinodular goiter is still uncertain. To obtain information on a number of unexplored immunological features, the distribution and characterization of T, B, and natural killer lymphocyte subsets were studied in the peripheral blood of 15 patients with multinodular goiter; 8 patients with Graves' disease (for reference purposes with a well-characterized autoimmune disease) and 29 age- and sex-matched healthy controls, combining double-staining immunofluorescence technique with monoclonal antibodies and flow cytometry. Although in both thyroid diseases increased CD3+ HLA-DR+ activated T cells (P < 0.01) were detected, in Graves' disease this was associated with decreased numbers of CD8 cells (P < 0.05) and an increased CD4/CD8 ratio (P < 0.01). These abnormalities were absent in multinodular goiter, which displayed increased CD8+ CD57+ cytotoxic/suppressor cells (P < 0.01). There was an increase in the percentage of natural killer cells expressing CD16 and CD57 antigens in multinodular goiter but not in Graves' disease. The B-cell associated antigens CD19 and CD19+ CD5+ were significantly increased in Graves' disease (P < 0.01), while the multinodular goiter patients exhibited only an increased number of B cells coexpressing the CD5 antigen (CD19+ CD5+), which was unrelated to the titers of anti-microsomal and antithyroglobulin autoantibodies. Our results point to the presence of several abnormalities of peripheral T, B, and natural killer lymphocytes in sporadic multinodular goiter, with a distribution pattern quite different from that observed in Graves' disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Lymphoid subsets in acute myeloid leukemias: increased number of cells with NK phenotype and normal T-cell distribution.

Natural killer (NK) and T subsets were analyzed with appropriate dual labeling by flow cytometry in peripheral blood (PB) (66 cases) and bone marrow (BM) (55 cases) from patients with de novo AML in order to determine: (a) their distribution at diagnosis, (b) the correlation between PB and BM in NK subpopulations, (c) their relationship with the clinical and hematological disease characteristics, and (d) the changes occurring upon achieving complete remission (CR). NK cells defined by the expression of CD56 in the absence of CD3 were significantly increased at diagnosis and their levels in PB correlated with those of BM. By contrast, NK subsets defined by CD16 expression (CD16+ CD2+ and CD16+ CD2- NK-cell subsets) as well as T lymphocytes with NK activity (CD56+ CD3+), although increased in PB, displayed normal levels in BM. An additional observation of interest was the expansion of an immature NK population lacking CD16 Ag expression (CD56+ CD16-). AML cases were divided into two groups according to the absolute number of NK cells in PB; patients with the highest levels showed an increased proportion of blast cells in PB (p = 0.01), monocytic subtypes (p = 0.03), and expression of CD11b, CD14, and CD4 antigens (p = 0.05). Infections at diagnosis were not related to the level of NK cells. In 19 patients who achieved complete remission the number of CD56+ CD3- cells tended to be reduced to within the normal range. Other T-cell populations, including the CD4 naive and memory cells, were also explored, their distribution being normal in the PB of AML patients. By contrast, the cytotoxic subset CD8+/CD57+ was significantly increased (p < 0.001). These data point to the existence of marked alterations of NK cells in AML patients, possibly reflecting a host-tumor immunological interaction.

Acute Disease↗
PubMed1993

Immunophenotypic characterisation of acute leukaemia after polycythemia vera.

AIMS: To analyze the immunophenotype of blast cells in patients with acute leukaemia after polycythemia vera, together with the most relevant clinical and haematological disease characteristics. METHODS: The immunophenotype was analysed in nine patients by immunofluorescence flow cytometry using a panel of 15 monoclonal antibodies. The DNA content of blast cells was determined using Vindelov's technique. RESULTS: The most relevant clinical and haematological disease characteristics included: the presence of enlarged spleen and liver by 56% and 67%, respectively; a moderate degree of leucocytosis with thrombocytopenia while haemoglobin was normal in 50% of patients. All patients received alkylating agents or hydroxyurea, or both. Interestingly, the chronic phase in patients receiving this latter drug was shorter. All cases showed a myeloid phenotype, four of them reactive only to early myeloid antigens (CD13/33); in the remaining cases the blast cells displayed granulomonocytic (CD14+, CD15+), erythroid (CD71 ), or megakaryocytic (CD61+, CD41+) markers. Coexpression of lymphoid related antigens (CD7, TdT, or CD19) was also detected. The morphological assessment of blast cells agreed with the immunophenotyping in five out of the nine cases. Blast cells from all six patients analysed displayed a diploid DNA content and the proportion of S-phase cells ranged from 0.4% to 4%. CONCLUSIONS: These findings suggest a pluripotential stem cell with myeloid commitment as the target cell of acute leukaemia after polycythemia vera.

Adult↗
PubMed1993

Expression of NK and lymphoid-associated antigens in blast cells of acute myeloblastic leukemia.

In the present study, the expression of two NK-associated antigens (CD56 and CD16) together with six 'classically' considered lymphoid-related markers (TDT,CD19,CD10,CD7,CD2,CD4) has been analyzed by appropriate dual combinations in 265 acute myelogenous leukemia (AML) patients. Among the lymphoid markers, CD4 and CD7 were those most frequently expressed by AML blast cells (58% and 21.6%, respectively) while the incidence of positivity for the other markers was lower: CD19 (7.8%), CD10 (10.9%), CD2 (11.4%), and TDT (11.3%). Regarding NK-associated antigens, CD56 was present in 41% of AML cases analyzed whereas CD16 was detected in only 23%. All but one of the CD16+ cases coexpressed the CD56 antigen. The expression of these antigens was not associated with the degree of cell differentiation assessed either by morphological or immunophenotypical criteria, with the exception of the correlation observed between monocytic leukaemias and the expression of the CD4, CD56, and CD16 antigens. Regarding the prognostic value of the markers investigated, CD56 expression was associated with a tendency for a better outcome whereas CD7 was the only antigen that had an adverse influence on the survival of AML patients.

Antigens, CD↗
PubMed1992

Developmental changes in rat liver mitochondrial populations analyzed by flow cytometry.

Isolated rat liver mitochondria were split into three density fractions when applied to a Percoll gradient. This phenomenon is observable in the fetus, in the early newborn (1 h), in the suckling newborn (7 days), and in the adult, suggesting that the three density fractions coexist regardless of the state of development. The medium-density fraction sharply decreased immediately after delivery, being replaced by the high-density fraction. Flow cytometry analysis of mitochondrial density fractions stained with rhodamine 123 showed the occurrence in each density fraction and in all developmental states studied of two distinct mitochondrial populations with different fluorescence intensities. Our results suggest that the high-fluorescence population might be an immature form of mitochondria that decreases with the progression of development, coinciding with the postnatal enhancement of mitochondrial respiratory efficiency.

Aging↗
PubMed1992

Long-term treatment results for acute megakaryoblastic leukaemia patients: a multicentre study.

The prognosis and long-term results of a group of 57 acute megakaryoblastic leukaemia (M7-AML) patients was analysed from a multicentre perspective. Ages ranged from 4 to 83 years, median 49 years; 30 were males and 27 were females. The median follow-up time was 7 months, range 1-24 months. Early exits occurred in 12 cases, their median age being 71 years. Forty-five patients were treated with combined aggressive chemotherapy (CT) (n = 26) or low-dose cytarabine (LD-AraC) (n = 19). The following results were obtained with combined CT or AraC, respectively. Complete remission (CR) rates were 73% and 84%, 12-month survival (SV) were 37% and 26%, 24-month SV were 12% and 11%, median SV 10 and 4 months, and relapse rates (RR) were 68% and 94%. These differences were not statistically significant. Irrespective of the treatment modality, the results were better for children (n = 10) than for adults (n = 35): RR rates were 90% and 74%, median SV: 7 and 5 months, 12-month SV: 40% and 22%, 24-month SV; 30% and 9%, and RR: 78% and 81%, respectively; these differences also were not statistically significant. In addition, a literature review of 42 patients from 18 previous reports is presented, including seven cases treated with allogeneic bone marrow transplantation (BMT). The best results were obtained with BMT: 12 and 24 month SV was 86% and the RR was 0%. On the above-mentioned basis, we feel that children and young adults with M7-AML should be offered BMT. In patients over 60 years old or not eligible for aggressive chemotherapy or BMT, an interesting possibility would be the use of LD-AraC which allows a high CR rate, followed by a classical consolidation regimen in order to prevent early relapses.

Adolescent↗
PubMed1992

Development of acute leukaemia after idiopathic myelofibrosis.

AIMS: To determine the characteristics of blastic transformation of idiopathic myelofibrosis. METHODS: The clinical and haematological features, as well as the morphological characteristics of blast cells, were analysed in nine adults with blast transformation. RESULTS: Most of the patients were male and had enlarged spleens and livers. Five of the patients had normal platelet counts, while all had pronounced anaemia and a moderate degree of leucocytosis. The duration of the acute phase was usually short: 16 (SD 8) weeks. Most myeloid cell lineages--granulocytic, monocytic, and megakaryocytic--were similarly distributed. One patient also had a hybrid (lymphoid-myeloid) phenotype. The morphological assessment of blast cells agreed with immunophenotyping in five out of the nine cases. The onset of the blastic phase was not related to previous treatment. CONCLUSIONS: A pluripotential stem cell with preferential myeloid commitment would be the target cell of blast transformation in idiopathic myelofibrosis. Our immunophenotypic data do not support the concept of a preferential association between megakaryocytic lineage and the acute transformation of idiopathic myelofibrosis. The absence of previous treatment in some cases suggests that this kind of evolution is part of the natural history of idiopathic myelofibrosis.

Acute Disease↗
PubMed1992

Concomitant chronic lymphocytic leukemia (CLL) and acute myeloid leukemia. Complete remission of CLL achieved with high-dose cytosine arabinoside.

The concomitant presentation of acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL) is rare with so far only eleven cases reported. In addition, the achievement of complete remission (CR) in CLL is exceptional and generally not assessed by immunophenotypical investigations. We report a case with a simultaneous occurrence of AML and CLL in which, in addition to the complete remission of AML, an eradication of the CLL clone was obtained following high-dose cytosine arabinoside. The immunophenotypic investigation of minimal residual disease showed that less than 1 x 10(-3) CD19+/CD5+ B-cells remained in bone marrow.

Acute Disease↗
PubMed1992

Prognostic value of S-phase white blood cell count in B-cell chronic lymphocytic leukemia.

Eighty previously untreated patients with B-cell chronic lymphocytic leukemia (B-CLL) were analyzed to study the proliferation rate of their peripheral blood (PB) leukocytes to determine its relationship with the extension of the disease and its value in discriminating among patients with similar tumor cell mass. The 80 B-CLL patients were distributed into two different groups according to the absolute count of PB S-phase leukocytes: a low proliferative group (less than 1 x 10(9)/I) of 48 patients and a high proliferative group (greater than or equal to 1 x 10(9)/I) of 32 patients. The high proliferative group displayed a higher incidence of splenomegaly (p less than 0.005), hepatomegaly (p less than 0.08), anemia (p less than 0.02) and thrombocytopenia (p less than 0.03) as well as a higher lymphocytic infiltration both in PB (p less than 0.0004) and in bone marrow (BM) (p less than 0.003). These patients also showed a higher incidence of a diffuse pattern of BM involvement (p less than 0.04), advanced clinical stages [stage III/IV (p less than 0.03) and group C (p less than 0.04)] and infections (p less than 0.0008) together with significantly lower IgG (p less than 0.03) and IgM (p less than 0.03) serum levels. Regarding the immunophenotype, there was a greater percentage of either CD19+ (p less than 0.06) and CD19+ CD5+ (p less than 0.05) B-cells, together with a greater reactivity for both the CD25 (p less than 0.04) and CD9 (p less than 0.08) antigens in the high proliferative group. According to the prognostic value of the PB S-phase leukocyte count it was seen that patients with low S-phase white blood cell (WBC) numbers displayed a significantly higher survival (p less than 0.03). In addition, multivariate analysis revealed that the S-phase WBC count, although partially related to other clinical and biological prognostic factors, displayed an important independent value in predicting early deaths in patients with B-CLL.

Aged↗
PubMed1991

Acute leukemia after a primary myelodysplastic syndrome: immunophenotypic, genotypic, and clinical characteristics.

We studied the nature of blast cells in 41 patients with acute leukemia following a previous primary myelodysplastic syndrome (MDS) by a combined multiparameter analysis including morphologic, immunophenotypic, and molecular genetic (Igs, T-cell receptor (TCR)-beta, -gamma, and -delta and the major breakpoint cluster region [M-bcr]) investigations. In addition, the clinical and hematologic characteristics according to the immunophenotype of blast cells were analyzed. Our results show that, although the granulocytic and/or monocytic lineages are those most commonly involved in these acute leukemias, other cell components, including the megakaryocytic and lymphoid, may be present (12% and 15% of the cases, respectively). Moreover, both morphologic and phenotypic studies show the frequent coexistence of two or three cell populations. Interestingly, in all cases the lymphoblastic component constantly displayed an early B phenotype (CD19+, CD10-, TdT+). Upon analyzing whether the type of MDS conditioned any differences in the immunophenotype of blast cells, we observed that, although the lymphoid lineage may be involved in all MDS subgroups, some differences emerge within the myeloid leukemic transformations. Thus, the refractory anemias with excess of blasts (RAEB) and RAEB in transformation displayed a significantly higher incidence of myeloblastic and megakaryoblastic transformations, while in the RA, RA with ring sideroblasts and chronic myelomonocytic leukemia, the granulo-monocytic phenotype predominated. In addition, our results show that the clinical and hematologic characteristics of these patients may be partially related to the immunophenotype of the blast cells. Ig heavy chain gene rearrangements were found in two of 19 patients analyzed (11%), one with a hybrid leukemia (lymphoid-myeloid) and the other with a granulo-monocytic phenotype. Two other hybrid transformations analyzed were in germline configuration. Gamma and delta gene rearrangements were found in 21% and 37% of these acute transformation, respectively. The TCR-beta and M-bcr were in germline configuration in all 19 cases studied. In summary, immunophenotype and molecular studies point to a pluripotent stem cell with preferential myeloid commitment as the target cell of leukemias following a primary MDS.

Acute Disease↗
PubMed1991

Incidence and clinical characteristics of hereditary disorders associated with venous thrombosis.

At present, different congenital defects in several proteins--antithrombin III (AT III), protein C (PC), protein S (PS), and plasminogen (PLG)--are known to be causes of hereditary predisposition to thrombosis (thrombophilia). The incidence of these hereditary disorders in our 204 patients (106 males and 98 females) with venous thromboembolism were 4% (three cases deficient in PC, three in PS, two in PLG, and one patient in AT III). Their families were studied. In all cases the disorders were inherited as an autosomal dominant trait. The first thrombotic episodes occurred at a age of below 40 years. There was no relationship between protein levels and the occurrence of thrombosis, although a significant relationship was observed between a positive history of thromboembolic disease and a diagnosis of protein deficiencies. We evaluated the differences between primary thrombosis and secondary thrombosis. The most common thrombotic sites were the deep veins. There were no differences between males and females. Evaluation of PC, PS, AT III, and PLG in patients with thromboembolic disease should be considered.

Adolescent↗
PubMed1991

Immunophenotypic, genomic and clinical characteristics of blast crisis of chronic myelogenous leukaemia.

We have studied phenotypic and clinical features in a consecutive series of 45 patients with chronic myelogenous leukaemia (CML) in blast crisis (BC). In addition, in 22 of these patients we have analysed the genotypic characteristics including immunoglobulin, T-cell receptor (TCR) and major breakpoint cluster region (M-bcr) gene organization. The granulomonocytic and megakaryoblastic lineages are the most commonly involved in these BC of CML (33% and 33% of cases, respectively); only 18% of our cases displayed a lymphoid phenotype. Moreover, both morphological and immunophenotypic studies revealed the frequent coexistence of two or three cell populations, especially when the megakaryoblast component is involved. The lymphoid BC displayed the highest incidence of complete remissions although this was not associated with a longer survival. Only minor differences between the different myeloid subgroups were observed. Immunoglobulin heavy chain (IgH) gene rearrangement was found in five of the six lymphoid BC and in one myeloid BC. Only one case showed k light chain gene rearrangement. In all but one myeloid BC the TCR-beta gene was in germline configuration. The TCR-gamma gene was rearranged in all lymphoid and one myeloid BC, while TCR-delta gene rearrangement was detected in 67% and 16% of the lymphoid and myeloid BC, respectively. Most of the lymphoid BC (4/5) had the M-bcr breakpoint in subregion 3, while the myeloid BC had the breakpoint either in subregion 2 or 3. No differences between the different myeloid phenotypic subgroups were observed in relation to breakpoint.

Antigens, CD↗
PubMed1991

Heterogeneity of T cell lymphoblastic leukaemias.

Twenty eight out of 170 consecutive cases of acute lymphoblastic leukaemia (ALL) were examined. They were of T cell origin, with the following distribution: seven (28%) cases had pre-T or prothymic features; nine (36%) cases showed early thymocytic features, six (24%) had cortical features; and three (12%) had a "mature" phenotype. The remaining three cases could not be sub-classified. A striking finding was that pre-T ALL differed from intrathymic ALL not only in the absence of both E rosettes and intrathymic differentiation antigens, but also in the expression of two non-lineage specific antigens HLA-DR and CD10. Both antigens appear in the bone marrow from the very first stages of lymphoid differentiation, implying that the origin for pre-T ALL is bone marrow. A comparison of the clinical features of pre-T and thymic ALL showed that pre-T ALL disease showed a pattern more similar to non-T ALL disease: a lower incidence of mediastinal mass, absence of extrahaematopoietic disease, lower white cell counts and haemoglobin concentrations, and a higher incidence of bone pain. No obvious difference in response to treatment was apparent. The results show that T-ALL is not only a heterogeneous immunological group but also suggest that it may have different origins: bone marrow for pre-T ALL and the thymus for thymic ALL.

Adolescent↗
PubMed1991

Circadian variation in the distribution of cells throughout the different phases of the cell cycle in the anterior pituitary gland of adult male rats as analysed by flow cytometry.

Flow cytometric analysis of nuclei stained with propidium iodide (PI) has been used to study the distribution of cells throughout the different phases of the cell cycle in the anterior pituitary gland of adult male Sprague-Dawley rats at different times of the day. According to PI fluorescence intensity the relative numbers of cells in S phase (cells with a DNA content between that of somatic cells in interphase (2n) and that of somatic cells after duplication of the DNA prior to cell division (4n] and G2/M phase (4n) were calculated. A significant circadian rhythm was found for cells in both the S phase (P less than 0.05) and the G2/M phase (P less than 0.01). The wave of cells in S phase with a peak at the middle of the light period (14.00 h) precedes by about 6 h the wave of cells in G2/M phase (peak at 20.00 h). Most of the DNA-replicating cells were found during the early S phase at 11.00 h, advancing further up to the middle of this phase at 14.00 h. Cells were distributed homogeneously throughout the S phase at 17.00 h. These data strongly suggest that the beginning of the light period triggers a wave of cells to leave G0/G1 into S phase.

Animals↗
PubMed1991

[Phenotypic changes in refractory and relapse acute lymphoblastic leukemias].

Out of a group of 220 acute lymphoblastic leukaemias (ALL) with phenotypic study at diagnosis, 18 were selected on which sequential studies were performed due to relapse (15 cases) or to lack of achievement of complete remission (primary resistant ALL, 3 cases). The purpose of this study was to analyse the incidence and characteristics of the possible antigenic changes with regard to the diagnosis. Along with the classic markers, a panel comprised of 20 monoclonal antibodies against lymphoid and myeloid antigens was used. Major phenotypic changes (acquisition of myeloid antigens CD13 and CD33) were found only in one case amongst the relapsing ALL (7%). Seven other patients (47%) showed minor phenotyping changes, including: 1) acquisition or loss of antigens (2 cases); 2) changes in more then 50% of any antigen's expression (4 cases); 3) both (1 case). These results might suggest that antigenic changes are rather frequent in relapsing ALL; however, none of such changes modified in our experience the phenotypic diagnosis so any change of this last should be regarded as an exceptional event. The majority of these antigenic changes consisted of the loss of maturation antigens (CD20) or acquisition of early markers (TdT, HLA-DR) or activation markers (CD38); this would mean that the relapsing blast cells show a functional status of activation and proliferation, with a phenotype more immature than that of the diagnosis, thus explaining the poorer prognosis of the patients in relapse. No phenotypic changes were found in the primary resistant ALL, which may indicate the persistence of the original cell clone without any alteration.

Adult↗