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Biomedical subjects

L Pegoraro

Publications and source records attributed to L Pegoraro.

At least 73 records · Page 4Linked to original sources
PubMed1987

Role of human serum and cellular factors on the growth of peripheral blood CFU-gm.

The effects of fetal calf serum (FCS), autologous serum (AS) and pooled human serum (PS) on granulocyte-macrophage progenitors (CFU-gm) from normal human peripheral blood mononuclear non-adherent cells (MNAC) were studied to determine optimal growth conditions. PS provided fewer variations and better growth conditions than AS and FCS. Moreover, serum inhibitors affecting both autologous and heterologous CFU-gm were detected in a small group (10%) of donors. Since CFU-gm from different donors display a relatively uniform cell-cycle status and membrane phenotype, under optimal growth conditions the number of CFU-gm probably reflects the size of the circulating myeloid progenitor cell compartment.

Adult↗
PubMed1987

Duplication of Ph and of 9q+ chromosomes during the blastic transformation of a CML case.

We describe the blastic transformation of a case of chronic myelocytic leukemia in which, among other abnormalities, one extra Philadelphia and one extra 9q+ were observed. Molecular studies and analysis of the clonal evolution of the karyotype led to the interpretation of such an unusual finding as the result of nondisjunction, rather than of a double t(9;22) translocation.

Adult↗
PubMed1987

A new specific chromosomal rearrangement, t(8;16) (p11;p13), in acute monocytic leukaemia.

The translocation t(8;16) (p11;p13) was found as the sole deviation from the normal karyotype in three patients with acute monocytic leukaemia. The bone marrow morphology was strikingly similar in the two cases where smears were available for re-evaluation: the leukaemic cells showed signs of differentiation, and active erythrophagocytosis was a particularly conspicuous feature. We suggest that t(8;16) (p11;p13) represents a new consistent abnormality in acute monocytic leukaemia, specifically associated with the differentiated subtype (M5b) and with pronounced phagocytic activity by the leukaemic monocytes.

Adolescent↗
PubMed1987

Rearrangement of the c-myc oncogene with heavy-chain immunoglobulin enhancer in tumor DNA from an acute lymphoblastic leukemia patient.

The DNA obtained from the leukemia cells of an acute lymphoblastic leukemia (ALL, L3 type) with a pre-B-phenotype and a typical t(8;14) chromosomal translocation showed a rearrangement juxtaposing the c-myc gene and the immunoglobulin (Ig) heavy-chain gene enhancer. This abnormality was only present in the leukemia cells of the patient and correlated with the clinical course of the disease. The breakpoint on chromosome 8 occurred within c-myc intron 1, between 790 and 638 base pairs upstream of c-myc exon 2. This breakpoint position was the nearest to the c-myc exon 2 so far described in Burkitt's type lymphoma-leukemias, and it mapped very near to the location of a major cryptic promoter used by truncated c-myc genes. In spite of what was detected in a human lymphoma cell line (Manca) carrying a similar rearrangement, in this case the amount of c-myc transcript was not increased compared to an Epstein-Barr virus-transformed normal lymphoblastoid cell line obtained from the same patient. This may in part be due to the breakpoint position and to the fact that the efficiency of the major cryptic promoter present within the first intron could have been affected by the translocation event. Finally, as previously suggested by others, the phenotype expressed by the leukemia cells supported the notion that this particular type of rearrangement (linking together the c-myc gene and the Ig heavy-chain gene enhancer element) may be associated with a subgroup of B-ALLs showing an immunologic phenotype relatively more immature than that of classical B-ALL.

Adult↗
PubMed1987

A human leukemic T cell line (PF-382) inhibits the growth of myeloid and erythroid progenitor cells.

We have recently described a human T cell line, named PF-382, obtained from the pleural effusion of a child with T-acute lymphoblastic leukemia (T-ALL), which expresses phenotypic and functional features of suppression. In this study we report that PF-382 spontaneously releases a factor which inhibits the in vitro growth of myeloid (CFU-GM) and erythroid (BFU-E) progenitor cells. The same effect is obtained when irradiated PF-382 cells are co-cultured with the hemopoietic precursors. In both instances, maximal inhibitory activity is exerted on day 14 CFU-GM and BFU-E obtained from the light density nonadherent fraction of normal human bone marrow and peripheral blood; this finding suggests that the target of the inhibition is represented by the more immature elements within the progenitor cell compartment. Progressive depletion of monocytes, T, B lymphocytes, and NK cells as well as recloning experiments indicate that the inhibitory effect is directly exerted on the target cell and not via an intermediate population of accessory cells. Partial purification by gel filtration and by subsequent high performance liquid chromatography demonstrates that this factor is a protein with a molecular weight of 47 kd. The physicochemical characterization and the specific functional properties suggest that the PF-382 inhibitory factor represents a lymphokine which differs from those so far reported. The PF-382 cell line provides a useful model toward a better understanding of the interrelations between T cell subsets and other hemopoietic compartments.

Colony-Forming Units Assay↗
PubMed1986

Serial transplantation of a human acute T lymphoblastic leukemia into nude mice.

A human acute T lymphoblastic leukemia line (PF-382) was serially transplanted into nude mice. No takes were observed in untreated nude mice, whereas solid tumors were observed in splenectomized and total body, sublethally irradiated mice. The minimal tumor-inducing dose and the latency time remained unchanged after the third and fifth serial transplants. Moreover, leukemic cells recovered from the 8th in vivo passages displayed the same differentiation antigens and chromosomal markers as the in vitro PF-382 cell line used for the first transplant. This stable and well-characterized experimental system could be a new model for T-lymphocyte differentiation and immune-reactivity against human leukemias.

Animals↗
PubMed1986

Modulation of in vitro myelopoiesis by LGL: different effects on early and late progenitor cells.

We describe here the modulatory activity of human peripheral blood natural killer (NK) cells on the growth and differentiation of myeloid progenitor cells at different stages of maturation. NK-enriched cell fractions containing 54 to 75% large granular lymphocytes (LGL) and displaying high levels of NK activity significantly inhibited the growth of late (7 day) granulocyte-macrophage colony-forming cells (CFU-GM) from about 50% of normal human bone marrow samples. However, the same fractions strongly enhanced the growth of early (14 day) stem cells from peripheral blood. Enhancing activity on early CFU-GM from blood was greater in highly purified NK cell preparations containing 96% LGL than in NK-depleted T cell preparations from the same donors. Analogous to the results when using the NK-enriched fractions, the NK-purified preparations inhibited late CFU-GM and stimulated the early ones. We conclude from these observations that human LGL have a modulatory effect on myelopoiesis depending on the maturation stage of the progenitor cell.

Bone Marrow Cells↗
PubMed1986

3' c-myc rearrangement in a human leukemic T-cell line.

The human leukemic T-cell line Hut 78, derived from a patient suffering from Sézary syndrome and expressing a mature postthymic membrane phenotype, shows a c-myc rearrangement beginning within 500 base pairs immediately 3' to the c-myc exon 3. Chromosome analysis of the Hut 78 reveals the presence of a hyperdiploid karyotype with a large number of markers and rearrangements, though trisomy is the only cytogenetic anomaly involving chromosome 8. Moreover, as the abnormal c-myc appears to be duplicated, a duplication of the chromosome 8 carrying the abnormal c-myc probably occurred. Unlike four other human leukemic T-cell lines tested, the Hut 78 cells express a high amount of c-myc transcript, suggesting that the 3' c-myc anomaly may cause a deregulation of the expression of this gene.

Base Sequence↗
PubMed1985

Insulin requirement of human leukemic cell lines.

The growth characteristics of human leukemic cell lines in serum supplemented medium and in serum free medium with and without the addition of insulin were investigated. No relation was found between the insulin binding capacity of the cells and their hormone-dependence for growth.

Cell Division↗
PubMed1985

A novel leukemia T-cell line (PF-382) with phenotypic and functional features of suppressor lymphocytes.

A human leukemia T-cell line (PF-382) spontaneously derived from the pleural effusion of a child with T-cell acute lymphoblastic leukemia is described. The cell line, which has been maintained in culture for over 10 months, has a modal number of 46 chromosomes and is characterized by a chromosomal abnormality, present in most of the cells, consisting of a translocation between chromosome X and chromosome 15 (46X,Xq-,15p+). The cells are not recognized by the OKT3 and OKT11 monoclonal antibodies (MoAb), nor do they form rosettes with sheep erythrocytes. By contrast, they react with the OKT6, Leu-1, and Leu-9 MoAb, which detect early T-lymphocytes, and express the more mature OKT8 antigen. The presence of the OKT8 marker is associated with suppressor activity on the pokeweed mitogen-induced proliferation and differentiation of normal B-cells, both by the PF-382 cells and by their supernatant. However, no cytotoxic activity against natural killer (NK)-sensitive target cells (K562) was found, indicating that the proliferating cells do not correspond to the subset of NK cells expressing the OKT8 antigen. Furthermore, the cells are incapable of both spontaneous and mitogen-induced interleukin-2 and interferon production. The ability of the PF-382 cell line to release a soluble factor(s) capable of modulating the differentiation of the B-cell compartment suggests that this new cell line represents a valuable model for the investigation of the interrelationships between T-cell subsets and other hematopoietic cell lineages.

Antigens, Viral↗
PubMed1984

A 14;18 and an 8;14 chromosome translocation in a cell line derived from an acute B-cell leukemia.

We have established a cell line, which we named 380, from a young male with acute lymphoblastic leukemia (FAB type L2). Karyologic analysis of this cell line indicates that it carries an 8;14 and a 14;18 chromosome translocation, which are characteristic of Burkitt lymphoma and of follicular lymphoma, respectively. This cell line is Epstein-Barr virus antigen-negative, reacts with monoclonal antibodies specific for B cells, and contains rearranged immunoglobulin heavy and light chain genes, but does not express human immunoglobulins. In this cell line, both mu heavy chain constant (C mu) loci are rearranged within the joining (JH) DNA segment. One of the JH segments on one of the 14q+ chromosomes is rearranged with a segment of chromosome 8, where the c-myc oncogene resides, while the other is rearranged with a segment of chromosome 18 where a putative oncogene, which we have called bcl-2, is located. The c-myc oncogene, which is translocated to one of the 14q+ chromosomes, is in its germ-line configuration more than 14 kilobases away from both the JH segment and the heavy chain enhancer that is located between the JH and mu switch region. Based on these findings, we propose a model of some aspects of B-cell oncogenesis according to which B-cell neoplasms carrying translocations involving the heavy chain loci on both human chromosomes 14 are the result of a multiple step process.

Antigens, Surface↗
PubMed1984

Soluble factor(s) released by Concanavalin A activated lymph node lymphocytes induce proliferation and maturation of chronic lymphocytic leukaemia (CLL) B lymphocytes.

An active supernatant (Ly Con A) was prepared by stimulating the normal human lymph node lymphocytes with Concanavalin A (Con A). Peripheral blood lymphocytes (PBL) from 3 healthy subjects and from 8 patients with chronic lymphocytic leukaemia (CLL) were cultured in the presence of Con A and Ly Con A. The latter induced a significant DNA synthesis both in normal and CLL lymphocytes. A proliferative response was still present in CLL after T lymphocytes depletion. The Con A and Ly Con A treatment also induced morphological changes in CLL lymphocytes consistent with plasma cell differentiation. In 3 cases the appearance of cytoplasmic light chains was detected by immunofluorescence. These findings suggest that peripheral blood B lymphocytes from CLL patients can be stimulated to maturation when helper factor(s) released by mitogen activated lymph node lymphocytes are provided.

Antibody-Producing Cells↗
PubMed1984

Effects of 12-o-tetradecanoyl-phorbol-13-acetate (TPA) on the colony growth of human T lymphocytes.

The T colony promoting activity of 12-o-tetradecanoyl-phorbol-13-acetate (TPA) was assessed in a double layer culture assay which is dependent on the simultaneous presence of phytohaemagglutinin (PHA) and a leucocyte rich underlayer. TPA (10(-8) M) incorporated in the overlayer in place of PHA was capable of promoting T cell growth in the form of clusters in all 37 experiments performed and in the form of colonies in more than 50% of the samples tested. However, the T colony promoting activity of TPA alone was markedly less evident and consistent than that of PHA (mean 13 +/- 19.9 s.d. colonies vs 168 +/- 78.6). TPA concentrations of 10(-6) M, 10(-9) M and 10(-10) M were practically ineffective. On the other hand, the number of colonies obtained when both TPA 10(8) M and PHA were incorporated in the overlayer was significantly higher (P less than 0.01) than that observed with PHA alone (mean 250 +/- 108.2 vs 178 +/- 84.5 colonies). When TPA concentrations of 10(-9) M and 10(-10) M were used in addition to PHA, the enhancing effect was less evident, while an inhibition of T colony growth was observed with TPA 10(-6) M + PHA. TPA 10(-8) M was also capable of enhancing T colony growth when incorporated in the leucocyte rich underlayer (222 +/- 98.6 vs 172 +/- 80.9 colonies). In all cultures with TPA the peak of growth was delayed compared with that of control experiments with PHA. These findings demonstrate that TPA, particularly when co-cultured with PHA, is an effective T colony promoting agent. The observation that the number of colonies formed in the presence of TPA plus PHA is higher than the sum of those observed with the two stimulators independently, suggests that their synergistic effect may be mediated via the production of colony stimulating soluble factors.

Clone Cells↗
PubMed1983

Changes in insulin binding activity during myeloid differentiation.

Insulin binding activity and its changes in relation to terminal differentiation were studied in the HL60 human promyelocytic cell line, and in myeloid cells from both normal bone marrow and chronic myeloid leukemia (CML) patients. After treatment with dimethylsulfoxide, the HL60 line began to differentiate into more mature myeloid cells. Treated and untreated HL60 cells were found to possess specific insulin receptors with characteristics similar to those of monocytes and granulocytes. Dimethylsulfoxide induced a progressive decrease in insulin binding, parallel to the increase in the proportion of differentiated cells. Myeloid cells from CML patients were used to study insulin binding characteristics during spontaneous differentiation. They were separated on Ficoll Hypaque into a light fraction, containing mostly undifferentiated cells, and a dense fraction, containing mostly granulocytes, with similar specific insulin receptor characteristics. Insulin binding capacity, however, was twice as high in the light fraction. To compare binding activity during normal and leukemic myeloid differentiation, cells from normal bone marrow and CML peripheral blood were fractioned by BSA density gradient into enriched fractions of one predominant cell type. Insulin binding decreased in the course of both differentiations. These findings indicate that leukemic immature myeloid cells possess a high number of specific insulin receptors, and that insulin binding decreases during both spontaneous and chemically induced terminal differentiation.

Bone Marrow↗
PubMed1983

Establishment of a Ph1-positive human cell line (BV173).

A new cell line (BV173) derived from a patient with Philadelphia chromosome (Ph1)-positive acute leukemia was compared with the Ph1-positive K562 and NALM-1 lines, which display the phenotypic characteristics of erythroid and pre-B cells, respectively. BV173 cells retained the Ph1 chromosome and had the morphologic and cytochemical features of undifferentiated blast cells. They lacked the membrane characteristics of mature B- or T-lymphocytes and did not react with monoclonal antibodies to the myelomonocytic cell lineage. Although they reacted with anti-glycophorin A antiserum, they failed to produce hemoglobin after butyric acid treatment. This line was similar to NALM-1 in that it bore common acute lymphoblastic leukemia antigen and la-like antigen, reacted with monoclonal antibodies directed against early stages of hematopoietic cell differentiation, and presented the nuclear enzyme terminal deoxynucleotidyl transferase. However, it differed from NALM-1 because it did not express cytoplasmic IgM, a marker of pre-B-cells. The new line can be considered a clonal expansion of leukemia cells blocked at an earlier differentiation stage than that for the other Ph1-positive cell lines.

Antibodies, Monoclonal↗
PubMed1983

Differentiation antigens of human hemopoietic cells: patterns of reactivity of two monoclonal antibodies.

Two mouse anti-human monoclonal antibodies (S3.13 and S5.7) raised against cells of acute myelogenous leukemia were found to react with antigens expressed on the surface of subsets of monocytes and lymphocytes. S3.13 precipitates a peptide of Mr 29,000, and S5.7 precipitates a peptide of Mr 20,000 present on the surface of all the cell types tested. These two surface antigens were distributed on discrete subpopulations of normal hemopoietic cells. The antibodies reacted with all (S5.7) or a subpopulation (S3.13) of peripheral blood T-lymphocytes, and with a subset of monocytes. Both antibodies reacted with bone marrow blast cell progenitors of the myelomonocytes and erythroid lineage. S5.7 also reacted with non-T-lymphocytes and with cells of the eosinophilic lineage. Both antigens disappeared from the cell surface during normal myeloid and erythroid differentiation. Thus, these monoclonal antibodies define the molecular characteristics and the cellular distribution of two differentiation antigens present on cells of the hemopoietic lineage.

Animals↗
PubMed1983

Changes in SRBC binding capacity and T-surface antigen expression on human peripheral blood lymphocytes stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA).

The expression of surface markers was analyzed on human peripheral blood lymphocytes after exposure to 12-O-tetradecanoylphorbol-13-acetate (TPA), a tumor promoter which is known to have a mitogenic effect on human T-cells. A significant decrease in the proportion of cells capable of binding to SRBC under different experimental conditions (active (EA), high affinity (EH), total (ET) rosettes) was observed after 20 hr exposure to TPA. After 4 days incubation, the ability to form EH and ET rosettes was recovered, while a significant increase in the proportion of EA and temperature stable (ES) rosettes compared with control cultures was observed. Using monoclonal antibodies directed against different T-lymphocyte subpopulations, a depression in the proportion of cells reacting with OKT3 (pan T) and OKT4 (helper/inducer) antibodies was observed, after both early and late exposure to TPA. On the contrary, the positivity with OKT8 (suppressor/cytotoxic) antibody was not affected at any time of culture. These findings suggest that, in normal blood, TPA can modulate the expression of T-cell receptors, and that T-lymphocytes with helper/inducer phenotype appear to be the target of the TPA-induced membrane changes.

Antibodies, Monoclonal↗