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Biomedical subjects

N Sacchi

Publications and source records attributed to N Sacchi.

88 records · Page 5Linked to original sources
PubMed1984

Phorbol ester-induced changes in human leukemic pre-B lines.

The genomic analysis of four non-T-leukemic lines NALM-1, KM-3, NALL-1, and NALM-16 shows a rearranged configuration of the immunoglobulin mu chain genes, indicating that they represent early B stages of differentiation. The differentiative potential of these pre-B cell lines was tested using the phorbol ester tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA). Phenotypic changes in the immunological marker profile (induction of BA-1 and BA-2 antigens) are observed, presumably reflecting events occurring in precursor B cells. However, no maturation to immunoglobulin mu chain production could be obtained. The limited maturation can be explained on the basis of possible aberrant mu chain gene rearrangements, or other mechanisms of a regulatory nature, preventing the transcription and/or the translation of rearranged mu chain genes.

Antigens, Neoplasm↗
PubMed1983

Acquisition of deoxyguanosine resistance by TPA-induced T lymphoid lines.

The human leukemic T cell line 8402, which contains terminal deoxynucleotidyl transferase (TdT) and phenotypically resembles precursor thymocytes, when exposed to the phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA) undergoes in vitro T maturation. TdT disappears from virtually all the cells and a fraction of TdT- -cells express specific T surface markers, such as the T3 determinant. Like T lymphocytes from the thymus, 8402 cells are extremely sensitive to the cytotoxic effect of deoxyguanosine (dGuo). As a consequence of TPA treatment, resistance to dGuo is observed in 8402, as well as in two other TdT+ lymphoid T cell lines, Molt-4 and CEM-10. These results suggest the occurrence of changes in deoxynucleoside metabolism in TPA-treated cells related to the in vitro maturation process. Maturation of 8402 cells, once started, progresses in the presence of additional physiologic stimuli provided by conditioned medium from lymphocyte culture, because a portion of cells display the T8+/T4- phenotype characteristic of cytotoxic/suppressor T cells. This in vitro lymphoid system may thus be used to study the relationships of molecular differentiation between precursor thymocytes and cytotoxic/suppressor T cells.

Animals↗
PubMed1982

Clinical relevance of terminal transferase and adenosine deaminase in leukemia.

Terminal Transferase (TdT), Adenosine Deaminase (ADA), immunological membrane markers, cytochemical reactivity and cytogenetics were analyzed in 226 patients with ALL, AUL and AML, in 70 patients with CML and in 3 cases of Ph' positive acute leukemia presenting as ALL. TdT was tested in peripheral blood and bone marrow with both the biochemical and immunofluorescence (IF) methods, and ADA was determined biochemically only in peripheral blood cells. By using conventional cytochemistry, cell surface markers determinations, TdT and ADA analysis, three distinct groups are recognized in ALL at presentation: T-ALL with TdT+ and very high ADA values; non-T, non-B ALL with TdT+ and intermediate levels of ADA; B-ALL with TdT absence and low levels of ADA. Clinical presentation and responses to therapy in adult and children ALL were correlated to TdT determinations. The median survivals in adults, calculated for TdT+ and TdT- groups, were 14.2 and 5.6 months, respectively. TdT and ADA were determined in ALL during remission. The wide fluctuation observed for TdT IF and ADA values prevented a reliable monitoring of remissions. At relapse, TdT and ADA values were similar to those found for ALL at presentation; TdT IF determinations were diagnostic in cases showing CNS involvement as the only localization. Forty per cent of AUL and 11% of AML cases were positive for TdT; the medians of ADA values of the TdT+ cases in both AML and AUL were several times higher than those obtained in the TdT- group. While TdT positivity and high ADA had a favorable prognostic value in AUL, similar conclusions can not be drawn at the moment for AML. In chronic phase of CML, TdT was strictly negative and ADA values were increased over the control line only in cases showing initial signs of transformation. In acute phase, the cases positive for TdT (32%) presented a significantly higher ADA activity than the TdT negative ones. The actuarial survival curves for the TdT+ and TdT- groups differ significantly, presenting median survivals from onset of phase of 11 and 4.8 months respectively. The three cases of Ph' positive ALL were all TdT+, presented high ADA values and entered chronic phase of CML after therapy.

Acute Disease↗
PubMed1981

DNA synthesis catalyzed in vitro by yeast extracts.

A procedure to prepare crude extracts from single colonies of Saccharomyces cerevisiae is described. Partially purified extracts catalyzed DNA synthesis directed by single-stranded fd DNA. Maximum activity requires the presence of ribonucleoside triphosphates although extensive DNA synthesis is observed in the presence of only deoxynucleoside triphosphates. Alkaline sucrose gradient analysis demonstrated that initiation of new DNA chains occurs in vitro and the DNA products synthesized are heterogeneous in size, Isopycnic analysis of the products of ribonucleotide-initiated fd DNA replication showed covalent linkage between the initiator RNA and the newly synthesized DNA. The fd-replicating capacity of extracts prepared from cell-division-cycle mutants, defective in events controlling DNA initiation of elongation, showed an increased thermosensitivity in the DNA replication reaction in vitro.

Centrifugation, Density Gradient↗
PubMed1980

A duplication-deficiency X chromosome in a girl with severe mental retardation.

Clinical and cytogenetic findings in a 14-year-old girl with severe mental retardation and partial Turner's syndrome are reported. An anomalous X was observed in the patient's karyotype. On the basis of QFQ, GAG and RBA banding studies, an Xq duplication (q12 leads to qter) and an Xp deficiency (p22 leads to pter) were apparent in this chromosome.

Adolescent↗
PubMed1979

Chromosome lesions in amniotic fluid cell cultures.

The frequencies of chromosome lesions were determined on 3537 mitoses in samples of varying sizes from cultures of 25 amniotic fluid specimens taken from patients at cytogenetic risk. The average percentage values of aberrant cells, including and excluding gaps, were 12.5 and 4.9, respectively. The corresponding values for fibroblasts and peripheral blood lymphocytes from normal adult donors, calculated under the same laboratory conditions, were 5.0 (including gaps) and 2.4 (excluding gaps) and 2.4 (including gaps) and 1.0 (excluding gaps), respectively. The hypothesis of a correlation between the increased incidence of chromosome lesions and the occurrence of abnormal karyotypes in amniotic fluid cell cultures is discussed.

Amniotic Fluid↗
PubMed1978

Adaptation to hypertonicity and selection of cell hybrids.

The ability to survive in hypertonic media varies markedly among different cell strains. This property was exploited to set up a selection procedure to isolate cell hybrids, in cell fusion experiments. The results of a cross between two EUE sublines, with a differential sensitivity to hypertonicity, are discussed.

Adaptation, Physiological↗
PubMedDate not supplied

The avian and mammalian ets genes: molecular characterization, chromosome mapping, and implication in human leukemia.

The mammalian homologs of the ets-region from the transforming gene of avian erythroblastosis virus, E26, consist of two distinct domains located on different chromosomes. Using somatic cell hybrid panels, the mammalian homologs of the 5' v-ets-domain, ets-1, were mapped to chromosome 11 in man, to chromosome 9 in mouse, and to chromosome D1 in cat. The mammalian homologs of the 3'v-ets domain, ets-2, were similarly mapped to human chromosome 21, to mouse chromosome 16, and to feline chromosome C2. We conclude that the ets sequence shared by the virus, chicken, and man is likely to contain at least two functionally dissociable domains, identifiable as ets-1 and ets-2. The human ets- locus is transcriptionally active and encodes a single mRNA of 6.8 kb, while the second locus, human ets-2 encodes three mRNAs of 4.7, 3.2 and 2.7 kb. By contrast, the chicken homolog, having a contiguous ets-1 and ets-2 sequence, is primarily expressed in normal chicken cells as a single 7.5 kb mRNA. Because chromosome translocations have been associated with different human hematopoietic malignancies, we have used our human probes to study specific translocations occurring in acute leukemias. The human ets- gene was found to translocate from chromosome 11 to 4 in t(4;11) (q21;23) and the human ets-2 gene was found to translocate from chromosome 21 to 8 in t(8;21) (q22;q22). Significantly, both translocations were associated with an expression of ets genes which differed from that found in normal diploid lymphoid cells.

Acute Disease↗