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Biomedical subjects

A Palumbo

Publications and source records attributed to A Palumbo.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1982

[Phagocytic activity and cytochemical characterization of acute human myeloblastic leukemia cells].

The ability of leukemic cells to phagocytize in vitro inert latex particles was tested in a group of non-lymphoblastic acute leukemia causes classified according to the FAB criteria. Promyelocytic, myelomonocytic, and myeloblastic leukemias were found to possess the highest percentage of cells with phagocytic activity. The cytochemical characterization of the cells revealed that the majority of phagocytic elements were negative for alpha-naphtyl acetate staining and positive for the peroxidase reaction. These unexpected findings could be explained by the impaired differentiation process of leukemic cells.

Humans↗
PubMed1982

[Expression of HLA-DR structure and a membrane-specific antigen by a granulocytopoietic line of acute leukemic blast cells].

Blast cells from peripheral blood of 32 patients with acute leukemia were tested for their ability to react with a monoclonal antibody (D1.B6) specific for HLA-DR surface antigen. In order to evaluate the degree of leukemic cell differentiation a monoclonal antibody (R1.B19) specific for the granulocytopoietic lineage was also employed. The results demonstrated that a considerable proportion of blast cell populations expressed the HLA-DR antigen, while only a small fraction of cells expressed the myeloid antigen.

Antibodies, Monoclonal↗
PubMed1982

Immunocytochemical localization of S-100 protein binding sites in synaptosomal fractions and subfractions.

1. Immunocytochemical evidence is presented of the ultrastructural localization of binding sites for S-100 protein in synaptosomal fractions and subfractions. Synaptosomes or isolated synaptosomal subfractions were first incubated with S-100, then centrifuged to remove unbound S-100, and finally fixed before treatment with anti-S-100 antiserum, using the unlabeled antibody peroxidase-antiperoxidase (PAP) method. 2. When intact synaptosomes were used, the immunoreaction product was localized to the postsynaptic density including the postsynaptic membrane. In some reactive synaptosomes, the presynaptic membrane was labeled as well, in the region of synaptic contact. No reaction deposit was found in the synaptic cleft or on intrasynaptosomal structures. Divalent cations (Ca2+ and Mg2+) were essential for S-100 to interact with synaptosomes. Of the synaptosomal subfractions tested, i.e., synaptic vesicles and intraterminal mitochondria, only synaptic vesicles showed immunoreactivity when treated with S-100 and anti-S-100 antiserum as described above. 3. The S-100 immunoreactivity in synaptic structures documented in this report parallels the distribution of the high-affinity binding sites for radiolabeled S-100 in synaptosomal fractions and subfractions.

Animals↗
PubMed1980

[Changes of fibrinolytic activity of human HL60 acute leukemia cells responses to chemically induced differentiation].

The fibrinolytic activity of human acute leukemia HL 60 and K 562 cells was studied by the (I25)I-fibrin plate method. The treatment of this cell lines with chemical inducers of differentiation such as Dimethyl sulfoxide (DMSO), 12-0-tetradodecanoilphorbol 13-acetate (TPA), and retinoic acid was found in some instance to affect such fibrinolytic activity. Increased activity was found during the myeloid differentiation induced by retinoic acid of HL 60, while the DMSO, another inducer of myeloid differentiation, and TPA, an inducer of macrophagic differentiation, both produced a decreased of the lytic activity. In the treatment with retinoic acid of th K 562 cells, which do not differentiate by such compound, we failed to show an increase of the fibrinolytic activity. Our data suggest that changes of the fibrinolytic activity of HL 60 are related to the process of differentiation.

Cell Differentiation↗
PubMed1980

[Insulin receptors in the HL60 human promyelocytic leukemic cells line].

The insulin binding characteristics of human promyelocitic HL60 cell line was studied by the use pf I(125) insulin. The binding activity was found to increase linearily both with the number of cells and with the incubation time. The competition curve with increasing concentration of unlabeled insulin demonstrated of specific receptors. The number of receptors was estimated to be 6.36 . 10(6) per cell.

Cell Line↗
PubMed1980

[Decrease of insulin binding to human acute leukemic cells during chemically induced differentiation].

The specific insulin binding activity of human promyelocitic HL 60 cell line during the myeloid and macrophagic differentiation induced by chemical compounds was investigated. Dimethyl sulfoxide (DMSO) and retinoic acid myeloid induced differentiation in HHL 60 cells was accompanied by a marked decrease of insulin receptors. In K 562 cell line, where DMS O has no effect on differentiation, the number of insulin receptors was only slightly affected. 12-0-tetradodecanoil phorbol 13-acetate (TPA) induced macrophagic differentiation of HL 60 cell line was also accompanied by a decrease of insulin binding activity. Our results support the hypothesis that during the process of terminal differentiation a decrease of insulin receptors occurs.

Cell Differentiation↗
PubMed1979

Antiarrhythmic effectiveness of creatinol O-phosphate in man.

Antiarrhythmic effectiveness of N-methyl-N-(beta-hydroxyethyl) guanidine O-phosphate (creatinol O-phosphate, COP) has been investigated in 10 patients with ischemic heart disease and frequent premature ventricular contractions (PVCs). Each patient received a random succession of treatment with the drug (1020 mg) and with a reference substance (solvent of COP) both administered i.m. twice a day over a 3-day period. In each patient a Holter ECG was recorded in the basal state and during the last 24 h of each treatment. Heart rate, PQ and QTc showed no changes. On the contrary, PVCs were significantly lower (P less than 0.01) with COP than with the reference substance. The drug showed a prevailing effect during daytime. Results are discussed in view of experimental observations suggesting that COP has a "membrane effect".

Adult↗