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A Rambaldi

Publications and source records attributed to A Rambaldi.

At least 19 recordsLinked to original sources
PubMed1992

Molecular evaluation of residual disease as a predictor of relapse in acute promyelocytic leukaemia.

Acute promyelocytic leukaemia (APL) is characterised by a unique fusion transcript, PML/RAR alpha. We tested for this transcript in 35 APL patients who were in apparent remission after various treatments. 11 of 13 patients who tested positive 4 months after achieving remission were in relapse 1-4 months later. All 22 patients who tested negative at 4 months were disease-free after a further 3 months to five years. The test may therefore prove useful in determining the need for additional treatment during clinical remission.

Carrier Proteins↗
PubMed1992

Molecular monitoring of the myl/retinoic acid receptor-alpha fusion gene in acute promyelocytic leukemia by polymerase chain reaction.

The acute promyelocytic leukemia (APL) t(15;17) translocation generates a myl/retinoic acid receptor-alpha (RAR-alpha) chimeric gene that is transcribed as a fusion myl/RAR-alpha messenger RNA. Using primer sets derived from RAR-alpha and myl cDNAs, we were able to amplify the breakpoint sites of the fusion transcripts of all 35 APL RNA samples by reverse polymerase chain reaction (PCR) and nested primer approach of two rounds of amplification. DNA fragments of different size were obtained according to the chromosome 15 breakpoints (intron 3-bcr 3; exon 6-bcr 2; and intron 6-bcr 1). bcr 1 and bcr 3 represent the regions of the myl locus most frequently involved among APL (48.5 and 34.2 of cases, respectively); bcr 3 constitutes 62.5% of cases among M3V as compared with 25.9% of M3 cases. The feasibility of monitoring the APL clone by PCR analysis in five APL patients who received different treatment (chemotherapy, all-trans-retinoic acid or bone marrow transplantation) was evaluated. In five of nine bone marrow samples of patients in complete remission, t(15;17)-positive cells could be detected by PCR analysis. We conclude that PCR amplification of the myl/RAR-alpha junctions represents the easiest and rapid method for diagnosis and monitoring of the APL clone.

Adolescent↗
PubMed1992

Identification of DNA rearrangements at the retinoic acid receptor-alpha (RAR-alpha) locus in all patients with acute promyelocytic leukemia (APL) and mapping of APL breakpoints within the RAR-alpha second intron. Italian Cooperative Study Group "GIMEMA".

Seventy patients with acute promyelocytic leukemia (APL) were characterized at the DNA level using genomic retinoic acid receptor-alpha (RAR-alpha) probes on Southern blot experiments. Sixty-two cases were defined as M3 according to the French-American-British (FAB) criteria, and eight had a diagnosis of microgranular or variant (M3v) APL. The use of two restriction enzymes and three probes exploring the second intron of the RAR-alpha gene allowed us to detect specific abnormal DNA fragments in every case, with clustering of rearrangements within the 20-kb intronic region between RAR-alpha exons II and III. A more detailed mapping of APL breakpoints was performed in 52 cases in which three EcoRI subregions of the RAR-alpha second intron were analyzed with corresponding probes. Comparison of clinical and hematological features in the three subgroups of patients with distinct RAR-alpha breakpoints did not show significant differences regarding age, peripheral blood (PB) counts, presence of coagulopathy, or FAB classification (M3 v M3v). Interestingly, a significant difference was observed in the M/F ratio of the three subgroups, with a higher incidence of rearrangements at the 5' end of the RAR-alpha second intron in female patients, and more frequent 3' breakpoints in males. The results of this study indicate that a unique genomic alteration consistently occurs on the 17q- derivative of the APL specific t(15;17) aberration. Moreover, the clinical relevance of RAR-alpha gene analysis both at diagnosis and in follow-up studies is further emphasized.

Adolescent↗
PubMed1992

Soluble intercellular adhesion molecule 1 is released by human melanoma cells and is associated with tumor growth in nude mice.

We have studied the cytokine regulation of cell surface and soluble intercellular adhesion molecule 1 (ICAM-1) expression on the human melanoma cell line A375M. Unstimulated cells express ICAM-1 on their cell surface but do not secrete significant levels of soluble ICAM-1. Interleukin 1, interleukin 6, tumor necrosis factor, and gamma-interferon all increased cell surface expression of ICAM-1. Tumor necrosis factor, interleukin 1, and gamma-interferon also caused the release of soluble ICAM-1. The serum of melanoma patients has been reported to contain elevated levels of soluble ICAM-1; however, the source of this ICAM-1 is unclear. The serum from nude mice bearing s.c. human melanoma tumors was found to contain soluble human ICAM-1. ICAM-1 levels showed a positive correlation with tumor weight. The release of ICAM-1 from melanoma tumors, in response to host-derived cytokines, may have relevance to immune recognition of the tumor.

Animals↗
PubMed1992

Acute undifferentiated leukemia with CD7+ and CD13+ immunophenotype. Lack of molecular lineage commitment and association with poor prognostic features.

The authors studied six adult patients with acute leukemia with these unusual characteristics: unclassifiable morphology and undifferentiated cytochemistry by French-American-British (FAB) criteria; concurrent expression of CD13 (and CD33) myeloid and early T-cell CD7 immune markers; no evidence of T-cell lineage commitment as determined by T-cell receptor beta (beta), gamma (gamma), and delta (delta) chain gene rearrangement study and cytoplasmic CD3 epsilon expression; and no evidence of myeloid cell lineage commitment, as shown by absent myeloid-specific c-fms proto-oncogene expression and negative myeloperoxidase ultrastructural staining (one case). Clinically, these diagnostic features matched with a poor prognosis, being associated with refractoriness to treatment, relapse and progression of disease, antecedent hematologic abnormality, and other malignancy. These cases may represent a distinct stem cell leukemia syndrome deserving immediate recognition and a nonconventional chemotherapeutic approach.

Acute Disease↗
PubMed1992

Genomic variability and alternative splicing generate multiple PML/RAR alpha transcripts that encode aberrant PML proteins and PML/RAR alpha isoforms in acute promyelocytic leukaemia.

The acute promyelocytic leukaemia (APL) 15;17 translocation generates a PML/RAR alpha chimeric gene which is transcribed as a fusion PML/RAR alpha mRNA. Molecular studies on a large series of APLs revealed great heterogeneity of the PML/RAR alpha transcripts due to: (i) variable breaking of chromosome 15 within three PML breakpoint cluster regions (bcr1, bcr2 and bcr3), (ii) alternative splicings of the PML portion and (iii) alternative usage of two RAR alpha polyadenylation sites. Nucleotide sequence analysis predicted two types of proteins: multiple PML/RAR alpha and aberrant PML. The PML/RAR alpha proteins varied among bcr1, 2 and 3 APL cases and within single cases. The fusion proteins contained variable portions of the PML N terminus joined to the B-F RAR alpha domains; the only PML region retained was the putative DNA binding domain. The aberrant PML proteins lacked the C terminus, which had been replaced by from two to ten amino acid residues from the RAR alpha sequence. Multiple PML/RAR alpha isoforms and aberrant PML proteins were found to coexist in all APLs. These findings indicate that two potential oncogenic proteins are generated by the t(15;17) and suggest that the PML activation pathway is altered in APLs.

Amino Acid Sequence↗
PubMed1992

Methylprednisolone dosage effects on peripheral lymphocyte subpopulations and eicosanoid synthesis.

Glucocorticoids have a major role in the treatment of glomerular diseases. Despite recent advances in understanding of their mechanism of action, very few studies have addressed the relative advantage of the wide range of different dose regimens employed in clinical practice. We studied the effects of methylprednisolone given intravenously for three consecutive days at the doses of 1 mg/kg (group 1, N = 7; group 2, N = 5), 5 mg/kg (group 3, N = 5) or 15 mg/kg (group 4, N = 6) on total blood peripheral leukocytes and on lymphocyte subsets in patients with glomerular diseases, and investigated whether such effects were a function of the drug concentration in the blood. Since glucocorticoids have an inhibitory effect on the formation of eicosanoids in different cells, we also investigated in the same patients the effect of 1 and 15 mg/kg methylprednisolone on systemic and renal eicosanoid synthesis. Results of pharmacokinetic study showed that the three different doses of methylprednisolone we used resulted in major differences in patient's exposure to the drug, and within the same dose there was a great individual variability. By contrast the three different doses of methylprednisolone induced a comparable drop in the absolute number of lymphocytes six hours after the first injection of methylprednisolone, while 24 hours later blood lymphocyte counts returned to the pre-injection values in all patients. Analysis of lymphocyte subsets showed a selective decrease in the number of circulating CD4+ and CD8+ cells six hours after methylprednisolone which was comparable in the four groups of patients studied. As for the effect of methylprednisolone on systemic and renal eicosanoid synthesis in patients with glomerular diseases, 1 and 15 mg/kg were equally unable to reduce thromboxane A2 (TxA2) and prostaglandin E2 (PGE2) release by circulating polimorphonuclear cells (PMNs). By contrast, methylprednisolone partially inhibited eicosanoid synthesis by PMNs in vitro. Consistent with the data on PMNs, urinary excretion of TxA2 and prostacyclin (PGI2) metabolites were unaltered by the different doses of methylprednisolone. By contrast urinary PGE2 was markedly and significantly reduced in patients given 15 but not 1 mg/kg. We conclude that 1 mg/kg methylprednisolone given to patients with glomerular diseases has the same effect on peripheral total blood leukocyte count and lymphocyte subsets than 5 and 15 mg/kg. The same is true for eicosanoid synthesis by PMNs. Renal synthesis of PGE2 is inhibited by 15 mg/kg but not by 1 mg/kg.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1992

Constitutive expression of IL-1 beta, M-CSF and c-fms during the myeloid blastic phase of chronic myelogenous leukaemia.

During the myeloid blast crisis (BC) of chronic myelogenous leukaemia (CML) non-random additional chromosome abnormalities occur in over 80% of patients. However, these cytogenetic changes have been reported to precede the clinical signs of CML-BC by several months to years suggesting that other biological events may participate in the multistep process of acute transformation of CML. The autocrine production of growth factors has been recently shown to occur in several haematological malignancies and particularly in acute myeloblastic leukaemia (AML). In the present report we demonstrate that IL-1 beta gene is expressed in almost all cases of CML in myeloid blast crisis. The secretion of IL-1 from CML blasts in culture supernatants was confirmed in all five of the patients we studied. A high proportion of cases showed constitutive expression of the M-CSF gene and many of the same patients often had a simultaneous co-expression of the proto-oncogene c-fms which encodes for the M-CSF receptor. After exposure of leukaemic cells to phorbol myristate acetate (PMA), release of M-CSF protein was documented in three of five patients studied. No significant interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) or granulocyte colony-stimulating factor (G-CSF), was detected in these patients demonstrating that a different pattern of growth factors secretion exist in AML and CML, where distinct molecular events are likely involved in the control of leukaemic proliferation.

Adult↗
PubMed1992

Interleukin-1 regulates cytokine gene expression in human mesangial cells through the interleukin-1 receptor type 1.

We have recently shown that interleukin-1 is a potent stimulus of gene expression and production of leukocyte chemotactic factors, colony-stimulating factors, and interleukin-6 in human mesangial cells in culture. Here, we sought to determine whether interleukin-1 induces its own gene expression in human mesangial cells. Interleukin-1 mRNA levels were quantitated by Northern blot analysis with total cellular RNAs isolated from human mesangial cells exposed for 6 h to medium alone or in the presence of human recombinant interleukin-1 beta (1 to 100 ng/mL). Interleukin-1 induced interleukin-1 mRNA expression in a dose-dependent manner. An additional finding of this study was that human mesangial cells constitutively express the 80 kd interleukin-1 receptor type 1 gene. When human mesangial cells were exposed to interleukin-1, interleukin-1 receptor expression was not modified. Similarly, other stimuli like tumor necrosis factor, transforming growth factor beta, or interleukin-6 did not modulate interleukin-1 receptor expression. Recombinant interleukin-1 receptor antagonist blocked the interleukin-1 mRNA as well as interleukin-6 and interleukin-8 mRNA accumulation induced by interleukin-1 beta. Lipopolysaccharide, which is a known stimulus for interleukin-1 transcription in several cell types, also induced interleukin-1 mRNA accumulation, thus indicating that lipopolysaccharide mediates interleukin-1 gene activation in human mesangial cells through an interleukin-1-independent pathway. These data support the pivotal role of interleukin-1 in regulating mesangial cell cytokine genes and may be taken to indicate the existence of an interleukin-1-mediated positive feedback loop that might control the secretion of active cytokines within the glomeruli when an immunological or inflammatory injury takes place.

Cells, Cultured↗
PubMed1991

Modulation of cell proliferation and cytokine production in acute myeloblastic leukemia by interleukin-1 receptor antagonist and lack of its expression by leukemic cells.

Interleukin-1 (IL-1) is spontaneously produced by acute myeloblastic leukemia (AML) cells. IL-1 also induces synthesis of colony-stimulating factors (CSFs) and sustains leukemic growth. An IL-1-specific inhibitor has been recently purified and cloned; this molecule binds to IL-1 receptors but has no IL-1 activity, fulfilling the characteristics of an IL-1 receptor antagonist (IL-1ra). Because high-affinity binding sites for IL-1ra were shown on AML cells by radioligand binding studies, we studied the effect of IL-1ra on the proliferative activity of blast cells isolated from 16 cases of AML. In each case, spontaneous proliferation was inhibited by addition of the IL-1ra in a dose-dependent manner (1 to 100 ng/mL). Culture supernatants of unstimulated leukemic cells contained IL-1 beta and granulocyte-macrophage CSF (GM-CSF), but when incubated with the IL-1ra, a reduction or disappearance of GM-CSF was observed in 8 of 10 cases, whereas spontaneous IL-1 production was reduced in four of seven cases. By Northern hybridization, IL-1 beta gene transcripts were shown in 20 of 23 AML cases, whereas IL-1ra-specific messenger RNA was present in only two of the patients studied. These data show a role for IL-1 in the spontaneous proliferation and cytokine production of AML cells and suggest that an imbalanced synthesis of IL-1 and of its natural receptor antagonist may contribute to the unrestricted growth of AML cells.

Binding, Competitive↗
PubMed1991

Endothelial cells express the interleukin-1 receptor type I.

Interleukin-1 (IL-1) profoundly affects a number of functions of vascular cells. Two distinct IL-1 receptors (IL-1R) are expressed on different cell types: the 80 Kd IL-1RI on T cells and fibroblasts, and the 68 Kd IL-1RII on B cells and myelomonocytic cells. The presence and functionality of IL-1R on vascular cells has been investigated by using polyomatransformed mouse endothelial cell (EC) lines (sEnd.1 and tEnd.1). These cells expressed specific and saturable binding sites for IL-1 (1,273 sites per cell with kd 9.5 x 10(-11) mol/L for sEnd.1, and 771 sites per cell with kd 8.5 x 10(-11) mol/L for tEnd.1, with radioiodinated IL-1 alpha as ligand). Binding of IL-1 was also evident at single cell level by autoradiography. By cross-linking studies, the molecular weight of the IL-1 binding protein on EC was approximately 80 Kd. This was confirmed by the presence in EC of mRNA for the 80 Kd IL-1RI. The IL-1RI on EC was apparently functional, since EC responded to IL-1 with IL-6 mRNA expression and IL-6 bioactivity production. These results were extended to human EC and vascular smooth muscle cells, which were also found to express mRNA for IL-1RI.

Animals↗
PubMed1991

Molecular evaluation of response to all-trans-retinoic acid therapy in patients with acute promyelocytic leukemia.

The advent of retinoic acid (RA) in the treatment of acute promyelocytic leukemia (APL) has led to a high frequency of short-lasting complete remissions (CR). We studied the response to RA by molecularly analyzing the RA receptor alpha (RAR alpha) locus, which has recently been shown to be rearranged in all APLs. Southern blot analysis demonstrated that the RAR alpha rearrangements persisted in the APL samples containing maturing myeloid cells 2 to 3 weeks after the start of RA treatment, but disappeared after 5 to 8 weeks, when the patients achieved CR. Our investigations provide clear evidence that CR occurs at molecular level and that there is reconstitution of an apparently normal, nonclonal hematopoiesis. Further, it shows that RA acts by triggering differentiation rather than by exerting a cytotoxic effect on the leukemic clone.

Adult↗
PubMed1991

RAR-alpha gene rearrangements as a genetic marker for diagnosis and monitoring in acute promyelocytic leukemia.

Acute promyelocytic leukemias (APLs) are characterized by a translocation that involves chromosomes 15 and 17. The translocation breakpoints have recently been identified and shown to involve the RAR-alpha gene on 17 and myl on 15. Here we report Southern blotting analysis of 26 APLs, including cases with normal karyotypes and atypical morphology, which showed RAR-alpha rearrangements in 92% cases, myl rearrangements in 73%, and either RAR-alpha or myl rearrangements in 100%. Despite a negative clinical and morphologic picture, DNA rearrangement analysis showed that neoplastic promyelocytes persisted in the bone marrow of two patients sampled after induction chemotherapy. Therefore, the RAR-alpha and myl rearrangements provide molecular markers for accurately diagnosing APLs and monitoring the course of the disease during and after chemotherapy.

Adolescent↗
PubMed1991

Translocation breakpoint of acute promyelocytic leukemia lies within the retinoic acid receptor alpha locus.

Acute promyelocytic leukemias (APLs) are characterized by a reciprocal balanced translocation that involves chromosomes 15 and 17 [t(15;17)]. We report the isolation and characterization of one of the two reciprocal break sites and demonstrate that the chromosome 17 breakpoint lies within the retinoic acid receptor alpha locus. Nucleotide sequencing of the 15;17 cross-over junction on 15q+ showed that the retinoic acid receptor alpha gene is truncated within its first intron, 370 base pairs upstream from the splicing donor site of exon II. Such a recombination would be expected to generate abnormal RAR alpha mRNA and protein. Southern blot analysis of a number of APLs with chromosome 15- and 17-derived DNA probes revealed similar 15;17 recombinations in the majority of other APLs. Our data are strong evidence that the retinoic acid receptor alpha gene plays a crucial role in the leukemogenesis of APL.

Animals↗
PubMed1991

Monoclonal lymphocytosis with villous lymphocytes: a chronic lymphoproliferative disease of CD11c+ B-cells.

Most of the circulating lymphocytes from three asymptomatic adults (one male, two female, age range 61-67 years) with isolated persistent lymphocytosis of between 7.1 and 10 x 10(9)/l possessed characteristic villous projections of the cell membrane. Morphological, histochemical, ultrastructural, immunological, and genotypic studies confirmed a clonal proliferation of tartrate-resistant acid phosphatase (TRAP)-negative CD5-CD10-CD25- and CD11c+ B-cells. In addition to CD11c, these cells expressed other adhesion receptors (LFA-1/CD11a, VLA-4/CD29/49d, ICAM-1/CD54, and LAM-1) and produced detectable amounts of interleukin-1 beta, interleukin-6, and in one case tumour necrosis factor-alpha mRNA. This monoclonal villous lymphocytosis (MVL) could be differentiated from B-cell chronic lymphocytic, prolymphocytic, and hairy cell leukaemias, and from previously recognized CD11c+ chronic B-cell leukaemia. A rare splenomegalic non-Hodgkin's lymphoma variant with circulating villous B-lymphocytes (SLVL), usually CD10+ and sometimes CD11c- and TRAP+, appears to be a closely related disorder. In all three patients the lymphocyte count increased very slowly, at a rate less than 5 x 10(9)/l per year, over 3-7.5 years of follow up, and a moderate splenomegaly eventually developed in one of the patients. Chemotherapy was never required. MVL may be a relatively benign clinical entity akin to SLVL within the group of CD11c+ B-cell lymphoproliferative disorders.

Aged↗