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Biomedical subjects

G Saglio

Publications and source records attributed to G Saglio.

At least 181 records · Page 10Linked to original sources
PubMed1990

Therapy-induced Ph1 suppression in chronic myeloid leukemia: molecular and cytogenetic studies in patients treated with alpha-2b IFN, high-dose chemotherapy and autologous stem cell infusion.

In this study, cytogenetic and molecular analyses were employed to assess the response to therapy in 29 chronic myeloid leukemia patients undergoing high dose chemotherapy followed by autologous stem cell infusion. Of these, 11 had previously achieved hematologic remission and cytogenetic improvement after alpha-2b interferon (IFN) treatment, whereas 18 underwent autografting in an early phase of the disease. In each case bone marrow samples were examined pre-treatment and at +2, +6 and +12 months in order to verify the degree of Ph1 suppression. In addition, the position of the breakpoint within the BCR region was mapped with multiple restriction enzymes. In 17 cases (59%) a significant Ph1 reduction was observed at +60 days (0-57% residual Ph1+ cells). In three of these cases, a complete cytogenetic response was confirmed at the DNA level by Southern blotting, but specific amplification of the BCR/ABL junction by the polymerase chain reaction (PCR), performed in two cases, still showed residual disease. The remaining 12 patients (41%) revealed a substantial persistence of Ph1+ metaphases (90-100%). Nine of 17 responding patients (53%) showed an increase of Ph1+ cells at 6 months, and five of 20 evaluated had a further increase at 12 months. With the exception of the results seen by PCR, comparison of molecular and cytogenetic techniques did not show significant differences. The variable degrees of Ph1 suppression observed did not appear to be associated with the position of BCR breakpoints. The factors predicting cytogenetic response to IFN and stem cell autograft and long-term durability of cytoconversion should be elucidated in further studies and with longer follow-up.

Base Sequence↗
PubMed1990

Use of a DNA probe in the diagnosis of enzootic bovine leukemia.

The authors describe the possibility of adopting a DNA probe in the detection of Bovine Leukemia Virus (BLV), using the molecular hybridization technique. The study was carried out on 18 seropositive Friesian cows taken from different stock farms during the persistent lymphocytosis phase. The presence of a possible BLV molecular variant was highlighted in one stock farm.

Animals↗
PubMed1990

A 3' truncation of MYC caused by chromosomal translocation in a human T-cell leukemia increases mRNA stability.

The proto-oncogene MYC is rearranged at its 3' end in the human T-cell leukemia line Hut 78 as a result of a translocation between the long arms of chromosomes 8 and 2. The nucleotide sequence at the breakpoint shows that the rearranged allele of MYC is truncated 24 nucleotides before the first poly(A)-addition signal. The 3' truncated MYC lacks a 61 nucleotide AT-rich sequence that has been reported to mediate selective mRNA degradation. We show that the truncation results in prolonged stability of MYC mRNA: the half life of the MYC mRNA in Hut 78, as well as in Rat 1A cells transfected with the truncated allele of MYC is increased by at least 5-fold. Our results document yet another mechanism by which MYC may be rendered pathogenic and dramatize the importance of mRNA stability in the regulation of MYC activity.

Base Sequence↗
PubMed1990

Immunoglobulin and Myc gene structure in lymphnode biopsies from HIV-positive patients with LAS and lymphoma.

The pattern of immunoglobulin (Ig) gene rearrangement and the genomic structure of the Myc locus were investigated in the DNA of 20 lymphnode biopsies of patients suffering from lymphoadenopathy-associated syndrome (LAS) and from 3 patients with Burkitt's lymphoma. Although polyclonality was the prevalent pattern of Ig gene rearrangement observed in LAS, in 30% of the cases discrete bands of Ig heavy chain gene rearrangement were identifiable due to the presence of monoclonal or oligoclonal cell populations. However, structural alterations of the Myc gene were not detected in any cases. As expected, in all three Burkitt's lymphomas studied, the lymphnode DNA displayed a clonal pattern of Ig heavy chain gene rearrangement. The Myc was altered in two cases, which presented a truncation of the gene beginning within a very short region of the first intron. By contrast, the breakpoint positions on chromosome 14 mapped in different regions of the Ig loci, which in both cases involved the switch (SH) area. Data confirm the relatively common occurrence of oligoclonal expansions within B cells in LAS and the frequent involvement of the Myc oncogene in the process of lymphomagenesis in individuals positive for human immunodeficiency virus (HIV).

AIDS-Related Complex↗
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

N-ras mutations in myeloid leukemias.

The presence of mutations activating the N-ras gene was investigated by the polymerase chain reaction technique in twenty patients with acute myeloblastic leukemia (AML) at onset and in four patients with Ph1 positive chronic myelogeneous leukemia (CML) either in chronic phase or in blast crisis. Four remission samples and four relapses from the AML cases were also studied. Mutations were found in five out of twenty (25%) untreated AML cases at onset. No mutations were detected in the complete remission samples, two of them with N-ras mutations during the leukemic phase. Two out of the four leukemia relapses were positive for the same N-ras mutation shown at presentation, whereas no new mutations were found in the other two initially negative cases. An N-ras mutation appeared during the blast crisis of one of the four CML, which were all negative during the chronic phase. In conclusion, whereas some data appear to be consistent with a role of the N-ras mutations as initiating events in myeloid leukemias, in other cases N-ras activation seems to represent a factor involved in progression. These data suggest that a partial overlapping between initiation and progression factors could exist in naturally occurring tumors.

Codon↗
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

Acute lymphoblastic leukemia with the 4;11 translocation exhibiting early T cell features.

We describe a case of ALL with the t(4;11) (q21;q23) translocation in which both surface markers and molecular analyses suggest an unusual early T cell involvement. While the morphologic and cytochemical studies showed an undifferentiated pattern, immunophenotypic data were suggestive of a very immature cell population which stained only for TdT and CD7. Moreover, in contrast to previous reports but in agreement with the immunologic findings, the IgH gene region retained a germline configuration. T cell receptor beta and gamma chain gene loci also showed a germline pattern, in accordance with the expansion of immature CD7+, TdT+ T cells.

Adult↗
PubMed1989

The human myeloma cell line LP-1: a versatile model in which to study early plasma-cell differentiation and c-myc activation.

The characteristics of a human cell line (LP-1) derived from the peripheral blood of a patient with IgG-lambda myeloma in leukemic transformation are described. The cells resemble immature plasma cells in that they exhibit a membrane phenotype that is intermediate between late B lymphocytes and plasma cells, even though they secrete IgG-lambda chains. Treatment of LP-1 cells with 12-0 tetradecanoylphorbol-13-acetate (TPA) or pokeweek mitogen (PWM) induces the appearance of surface markers and ultrastructural features typical of mature plasma cells but does not affect their proliferative activity. Molecular analysis of the cell line showed an increased expression of the c-myc protooncogene and the presence of abnormally sized transcripts. Conventional cytogenetics and pulsed-field gel electrophoresis showed no structural rearrangements of the c-myc gene, suggesting that the abnormal c-myc expression may be due to point mutations or small deletions within the gene. The LP-1 cell line is a useful model in which to study the process of B-cell maturation; such study may lead to the uncovering of unusual mechanisms of c-myc activation. Furthermore, the LP-1 cell is a potential partner in the generation of human hybridomas.

B-Lymphocytes↗
PubMed1988

Soluble factor(s) released by the PF-382 T-cell line enhances the stimulatory effect of monocytes on the BFU-E growth.

PF-382 is a human T-cell line that has been shown to elaborate factors that modulate normal hemopoiesis in vitro. In the present study we report that this cell line constitutively releases in both serum-containing and serum-free supernatants a potent enhancer of BFU-E growth. The factor(s), partially purified by gel filtration, is a heat-stable molecule(s) degradable by trypsin and 2-mercaptoethanol treatments, equally active on bone marrow and peripheral blood erythroid progenitor cells, but not on CFU-GM. Unlike other sources of BPA, this stimulatory factor(s) exerts its effect in the presence of mononuclear adherent cells. In fact, the addition of conditioned medium obtained by 48 hr preincubation of isolated monocytes with 10% PF-382 supernatant (M-CM2) or the concomitant addition of supernatant from PF-382 cells (PF-382-CM) and from unstimulated monocytes (M-CM1) are capable of fully replacing the presence of monocytes in the BFU-E assay. Since the independent addition of PF-382-CM or of M-CM1 is devoid of stimulatory function, we suggest that the PF-382 derived BFU-E growth inducer, which differs from IL-1, IL-3, IL-4, GM and G-CSF, exerts its activity "via" a synergistic mechanism with a monokine.

Cell Division↗
PubMed1988

A frequent A gamma-hereditary persistence of fetal hemoglobin in northern Sardinia: its molecular basis and hematologic phenotype in heterozygotes and compound heterozygotes with beta-thalassemia.

A survey of hemoglobinopathies in northern Sardinia revealed a high frequency (0.3%) of carriers of a hematologic condition characterized by increased expression of fetal hemoglobin during adult life (hereditary persistence of fetal hemoglobin or HPFH). In spite of a normal hematologic phenotype, the heterozygous carriers for this condition display about 12% HbF, almost exclusively of the A gamma type; compound heterozygotes with beta-thalassemia have 20%-26% HbF and run a very mild clinical course. The sequence analysis of the cloned A gamma gene linked to the HPFH determinant revealed the presence of a G----A substitution at position -117 of the A gamma-globin gene promoter; the same mutation occurs also in Greek HPFH, although associated with different restriction polymorphisms. Another hereditary condition characterized by increased HbF (alpha 2 A gamma 2) level and a mild thalassemia phenotype in Sardinia is associated with the -196C----T substitution in the A gamma-globin gene promoter (Sardinian delta beta-thalassemia). Population studies using oligonucleotides complementary both to the -117 G----A and -196C----T mutations and the corresponding normal sequences confirm the presence of these mutations only in HPFH and delta beta-thalassemia chromosomes and exclude these changes being common DNA polymorphisms.

Female↗
PubMed1988

Distribution of Ha-RAS-1 proto-oncogene alleles in breast cancer patients and in a control population.

The frequencies of 13 different Ha-ras proto-oncogene alleles have been estimated in 92 breast cancer patients and 60 unaffected individuals. The Ha-ras alleles can be identified using a DNA restriction fragment length polymorphism (RFLP) closely linked to the 3' end of the gene, and are characterized by a different length due to a region of sequences repeated a variable number of times (variable tandem repeats, VTR). The statistical analysis of the data obtained shows that the frequency of alleles ranging between specific length limits is significantly higher in breast cancer patients than in controls. The same applies to specific genotypes bearing the aforementioned alleles. This suggests that the inheritance of these alleles may be associated with an increased risk of developing breast cancer.

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↗