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Biomedical subjects

A Tassinari

Publications and source records attributed to A Tassinari.

At least 19 recordsLinked to original sources
PubMed1991

Cytogenetic events after bone marrow transplantation for Philadelphia chromosome positive chronic myeloid leukemia.

Allogeneic bone marrow transplantation is the only way to cure patients with Ph1+ chronic myeloid leukemia. It is commonly assumed that, in order to obtain a cure for the patients, the leukemic clone must be completely destroyed by the conditioning treatment and the donor's bone marrow must repopulate the hemopoietic niches leading to a "complete chimera". However, cytogenetic analyses, supported by molecular ones, indicate that Ph1+ cells, far from being completely destroyed by chemo-radiotherapy may persist for a long time, probably in the majority of the patients. As demonstrated by the outcome of patients receiving T-cell depleted marrow, immune mechanisms must be involved in controlling and progressively reducing the size of the residual leukemic clone. Furthermore, immunodulating therapeutic strategies, represented by cyclosporin-A discontinuation or alpha interferon treatment, may successfully reduce the Ph1+ cell population even after a full relapse.

Bone Marrow Transplantation↗
PubMed1990

New type of Bcr/Abl junction in Philadelphia chromosome-positive chronic myelogenous leukemia.

A new and rare type of Bcr/Abl junction between exon C3 of the 3' portion of the Bcr gene and Abl exon 2 has been identified in the leukemic cells of two Ph1-positive chronic myelogenous leukemia patients in chronic phase. This is the fourth type of Bcr/Abl junction so far identified in Ph1-positive hematologic malignancies and is a consequence of an unusual breakpoint position on chromosome 22 that falls approximately 20 kb downstream of the major breakpoint cluster region (bcr) of the Bcr gene. The new hybrid mRNA is 540 base pairs (bp) longer than that expressed by the K562 cell line and could codify for a Bcr/Abl protein carrying 180 additional aminoacids with respect to the larger P210 protein so far identified. The hematologic phenotype expressed by the two patients carrying this unusual type of Bcr/Abl rearrangement does not significantly differ from that commonly seen in chronic myelogenous leukemia.

Amino Acid Sequence↗
PubMed1990

Molecular and cytogenetic studies of a patient with Philadelphia-negative, BCR-positive chronic myeloid leukemia and t(12;12)(q13;p12).

A patient with Philadelphia (Ph1)-negative, breakpoint cluster region (bcr)-positive chronic myeloid leukemia (CML) is reported. Pulsed-field gel electrophoretic analysis demonstrated the comigration of both ABL and BCR sequences on the same BssHII and SacII fragment. Moreover, in situ hybridization studies demonstrated that ABL sequences had been moved from band 9q34 to 22q11 and that the additional t(12;12)(q13;p12) was not involved in the ABUBCR related translocation. Nevertheless, a possible role of oncogenes or regulatory sequences activated or inhibited by the additional translocation cannot be excluded.

Adult↗
PubMed1990

ABL proteins in Philadelphia-positive acute leukaemias and chronic myelogenous leukaemia blast crises.

The Philadelphia chromosome (Ph1) is present in 95% of chronic myelogenous leukaemias (CML) and 15% of acute lymphoblastic leukaemias (ALL). This cytogenetic marker is due to a t(9;22) translocation, which causes a rearrangement of the ABL oncogene. In order to better define the relationship between type of genomic rearrangement, variant ABL protein expressed and haematological phenotype, a series of Ph1-positive acute leukaemias, both myeloblastic (AML) and lymphoblastic, and several CML lymphoid blast crises have been analysed at the DNA and protein level. The results confirm the presence of the ABL protein P210 in all cases of CML, ALL and AML positive for rearrangement in the bcr region of chromosome 22, and, surprisingly, in one AML case apparently negative for bcr rearrangement. The ABL protein P190 was found to be present only in cases of ALL negative for bcr rearrangement. Polymerase chain reaction (PCR) analysis of the types of 9/22 junctions present in the mRNA of CML lymphoid blast crises showed no evidence of 'ALL-type' transcripts.

Adult↗
PubMed1989

Cytogenetic and molecular studies in patients with chronic myeloid leukemia and variant Philadelphia translocations.

Out of 105 Philadelphia (Ph) positive chronic myeloid leukemia patients analyzed, six (5.7%) carried a variant Ph translocation, namely t(6;9;9;10;22)(q24;p13;q34;p15;q11); t(9;13;22)(q34;q21;q11);der(2)(2pter----2q31::9q21---- 9q34::22q11----22qter) and der(9)t(2;9) (9pter----9q21::2q31----2qter);t(7;9;22)(q11;q34 ;q11), 14q + ;t(7;9;22)(q35;q34;q11), and t(9;11;22) (q34;q13;q11), respectively. Five of these patients were analyzed with Southern blotting. Three of them showed an atypical molecular pattern; namely, the patient with t(9;13;22) showed no rearrangement in the breakpoint cluster region (bcr), the patient with t(7;9;22)(q35;q34;q11) showed a 3' deletion, and the patient with t(7;9;22), 14q + showed a bcr rearrangement 3' to the exon 4 of the M-BCR. Chromosome in situ hybridization studies demonstrated that in patient one, a two-step translocation occurred: the first step moved the 3' bcr from chromosome 22 to chromosome 9, and the second moved the terminal part of 22q, carrying the c-sis protooncogene, to 10p. Variant Ph translocations appear to be associated with atypical molecular breakpoints.

Chromosome Banding↗
PubMed1989

Molecular characterization of Ph' + hybrid acute leukemia.

The configuration of the immunoglobulin heavy chain (IgH), T-cell receptor (TcR) beta and gamma chain regions, and the major breakpoint cluster region (M-bcr) genes were analysed in four cases of Ph' + acute leukemia (AL). Monoclonal rearrangements of the IgH region were detected in three cases exhibiting two phenotypically distinct cell populations (i.e. one lymphoid and one myeloid. In one of these cases, identical genetic events were observed by molecular analysis of FACS separated blasts. Multi-lineage rearrangements involving also the TcR gamma gene were observed in a biphenotypic AL showing co-expression of markers. The lack of rearrangements within the M-bcr gene, together with demonstration in one case of the Ph' + AL specific p190 protein product, pointed against the occurrence of chronic myeloid leukemias presenting in blastic transformation. Our results imply that such cases are to be considered as true AL and should therefore be included in the definition of hybrid AL.

Acute Disease↗
PubMed1989

Ontogeny, gene rearrangements and immunophenotype of acute leukaemias.

The progressive availability of more sophisticated technologies has over the last few years allowed a more precise definition of the biological properties of acute leukaemia cells. This, in turn, has enabled to recognize the ontogeny of practically all cases, with particular emphasis to acute lymphoblastic leukaemia, the lineage affiliation of which had, for many years remained uncertain in over half of the cases. Here, we shall review the main achievements, obtained with extensive immunotyping coupled to the use of probes for the immunoglobulin and T-cell receptor genes, which have led to these important clinico-biological acquisitions, and discuss specific situations in which this combined phenotypic and genotypic approach (as well as response to cloned growth factors) may be of particular value.

Antigens, Differentiation↗
PubMed1989

Evaluation of complete remission in hairy cell leukemia patients treated with alpha-IFN.

In 10 HCL patients, who following treatment for more than 1 year with alpha-IFN, had achieved a normalization of the splenomegaly and a disappearance of circulating hairy cells together with a complete restoration of all peripheral hematological values, a multiple assessment of the apparent complete remission (CR) was carried out. The presence of residual disease was investigated by bone marrow histology, bone marrow immunohistochemistry, immunoglobulin (Ig) gene analysis and on the basis of the serum levels of the soluble form of the Interleukin-2 receptor (sIL-2R). Examination of bone marrow biopsies showed a pattern of CR in 5 cases; 4 of them revealed no evidence of Ig heavy chain gene rearrangement, as well as a near normalization of the serum levels of sIL-2R. Immunohistochemical studies were carried out on embedded paraffin sections with the monoclonal antibody 4KB5 (CD45R) and were assessable in 4 of the 5 patients considered in CR and in 3 of the 4 cases with no Ig gene rearrangement. In 2 the pattern of CR was confirmed, while in the 3rd a minimal but persistent disease (5%) was suspected.

Adult↗
PubMed1988

Multilineage cell involvement in Ph1-negative, bcr-negative chronic myeloid leukemia.

We report a case of Ph1-negative, bcr-negative CML-BC, in which the primary leukemic cells displayed T-related antigens (CD7, CD4) in addition to HLA-DR and CD25 determinants. No B-lymphoid, myeloid and megakaryoblastic surface antigens were detected. In spite of this phenotype, DNA analysis revealed a germ-line configuration of the T-cell receptor beta chain gene region. Moreover, in-vitro culture studies demonstrated a proliferative response of the blast cell population to natural and recombinant myeloid-related factors, while no proliferative signal was observed in the presence of IL-2. The myeloid lineage was further demonstrated by the expression of myeloid-associated antigens on cultured blast cells, which still retained the CD7 antigen. Finally, cytogenetic analysis revealed a monosomy 7 which is usually associated with a stem cell leukemia. These results support the hypothesis that Ph1-negative, bcr-negative CML is characterized by the involvement of a multipotent stem cell capable of multilineage expression and indicate that differentiative and proliferative assays provide a further tool towards a more precise recognition of hematological disorders of uncertain origin.

Aged↗
PubMed1988

Cytoskeleton organization of normal and neoplastic lymphocytes and lymphoid cell lines of T and B origin.

An anomalous organization of the cytoskeleton has been described in lymphocytes from chronic lymphatic leukaemia and in only few cell lines. We have now studied normal and neoplastic lymphocytes and lymphoid cell lines of both T and B lineage in order to detect morphological differences in the expression of microfilaments and intermediate filaments. Microfilaments appear to be well expressed by all the B cells, whereas a rich network of intermediate filaments is present in T cells and plasma cells. Most prominent changes occur in the latter system, which is almost lacking in cells of B chronic lymphatic and hairy cell leukaemia. Although the significance of the present findings is not yet clear, one might speculate that such alterations account for some of the aberrant functions and peculiar biologic properties of neoplastic lymphocytes.

Actin Cytoskeleton↗