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Biomedical subjects

T Barbui

Publications and source records attributed to T Barbui.

At least 235 records · Page 13Linked to original sources
PubMed1987

Histone H1(0) is synthesized by human lymphocytic leukemia cells but not by normal lymphocytes.

Using a two-dimensional gel electrophoresis system (sodium dodecyl sulphate/acetic acid-urea-hexadecyltrimethylammonium bromide) coupled with fluorography, we investigated the synthesis of H1 isoproteins in leukemic cells obtained from peripheral blood of eight children suffering from acute lymphoblastic leukemia (ALL) (four T-ALL, three common ALL, and one B-ALL) and in normal peripheral lymphocytes. H1 was synthesized in leukemic cells but not in normal lymphocytes. Inhibition of DNA synthesis with hydroxyurea and 1-beta-D-arabinofuranosylcytosine induced an increase of relative synthesis of H1(0) in leukemic cells but did not induce any detectable synthesis of H1 in normal lymphocytes. H1(0) synthesis was also undetectable in peripheral lymphocytes of leukemic children in complete remission after chemotherapy and in lymphocytes of a homozygotic twin of a leukemic patient. H1(0) may be a marker of malignant transformation of lymphocytes and as such could be of use for early detection of relapse in patients with acute lymphocytic leukemia in apparent complete remission.

Electrophoresis↗
PubMed1986

Three abnormal fibrinogen variants with the same amino acid substitution (gamma 275 Arg----His): fibrinogens Bergamo II, Essen and Perugia.

We report on three unrelated individuals with the same uncommon type of dysfibrinogenemia, originating from Bergamo, Essen and Perugia. None of them showed bleeding symptoms while the Bergamo patient and members of her family presented with a thrombotic tendency. The presence of a defective fibrinogen was suggested by prolonged thrombin and reptilase times. Furthermore, fibrinogen concentrations of less than 0.28 g/L were determined by the functional assay whereas values of 1.5-2.4 g/L were measured by heat precipitation or electroimmunoassay. Fibrinogen was isolated by affinity chromatography on insoluble fibrin monomer. The rate of fibrinopeptide release by thrombin was normal while the fibrin polymerization reaction was strongly delayed. An abnormal peptide (gamma 265-310) was isolated by high-performance liquid chromatography after cyanogen bromide cleavage of the purified gamma-chain of fibrinogen Bergamo II and Essen. The same peptide was also isolated following cyanogen bromide treatment of the intact fibrinogen Perugia. Sequence analyses of these peptides demonstrated the same amino acid exchange in all three fibrinogens: gamma 275 arginine----histidine. The described fibrinogen variants appear to possess a molecular defect which has thus far only been observed in fibrinogen Haifa.

Amino Acid Sequence↗
PubMed1986

Induction of cytotoxicity by interleukin-2 in T gamma-lymphoproliferative disorders.

We have studied 7 patients with T gamma-lymphoproliferative disorders, in whom 78-88% of circulating nonadherent lymphocytes had the morphology of large granular lymphocytes (LGL) as assessed by light and transmission electron microscopy. The main common features of the membrane phenotype of these LGL expansions included expression of T3, HNK-1 and AB8.28. Other monoclonal antibody-defined surface markers of LGL (OKM1, B73.1, N901) were variably expressed or absent in these patients. Patients' LGL had little or no natural killer (NK) activity but mediated antibody-dependent cellular cytotoxicity (ADCC). Exposure to interferons (type B or gamma) for 20-72 hr resulted in no appreciable induction of cytolytic activity. In contrast, culture in the presence of interleukin-2 (IL-2) for 3 days resulted in the expression of strong cytolytic activity in all the patients tested against an NK-susceptible (K562) and an NK-resistant (Daudi) target. The expression of T3 antigen, the low levels or lack of native NK activity and the induction of consistent cytotoxicity by prolonged exposure to IL-2 led us to suggest that the cells expanding in these subjects are related to the effectors involved in lymphokine-activated killer (LAK) activity.

Adult↗
PubMed1986

Platelet dysfunction in splenectomized patients with hairy cell leukemia.

Platelet function was assessed in 17 patients with hairy cell leukemia who had undergone splenectomy. Defective PAF-induced aggregation and selective reduction of beta-thromboglobulin were found in platelets from six and eight patients respectively. These defects were not necessarily associated with bleeding complications.

Adult↗
PubMed1986

Generation of procoagulant activity by hairy cells in response to endotoxin and phorbol esters.

Several investigators have suggested that hairy cells are neoplastic B lymphocytes. These cells, however, also share some biological properties with mononuclear phagocytes. A property of these cells is the capacity to generate procoagulant activity (PCA) in response to a variety of stimuli. In this study we investigated the PCA of peripheral blood hairy cells in 19 consecutive patients with hairy cell leukaemia (HCL). Monocyte-depleted blood mononuclear cells, tested immediately after isolation, expressed little, if any, activity. However, after exposure to endotoxin, a marked increase in PCA was observed (42.1 +/- 8.7 vs 1.3 +/- 0.2 units/5 X 10(1) hairy cells). A significant correlation was found between the number of lymphocytes/hairy cell and the level of endotoxin-induced PCA suggesting that lymphocytes potentiate the procoagulant response of hairy cells. When stimulated with 12-0-tetradecanoyl-phorbol-13-acetate (TPA), patients' cells produced about 2-8 times more PCA than endotoxin-stimulated cells. The PCA induced by endotoxin and TPA was identified as tissue factor. These findings suggest some further relationship between hairy cells and monocytes.

Adult↗
PubMed1986

Lymphokine production in T gamma lymphoproliferative disorders.

We have studied five patients with chronic lymphocytosis consisting of large granular lymphocytes (LGL). The increased numbers of LGL in these patients had little or no natural killer activity, mediated antibody-dependent cellular cytotoxicity, and were induced to kill tumour lines after culture for 3 days with interleukin 2 (IL-2). Patients' LGL showed considerable reactivity with HNK-1 and AB8.28 monoclonal antibodies (MoAb), whereas positivity for OKM1 and N901 was found in only two subjects, and only one patient reacted with B73.1. No appreciable reactivity has been found with anti-Tac MoAb in the four patients tested. In the absence of stimulation, the patients' LGL produced no IL-2 and only minimal amounts of IL-1 and interferon (IFN). On stimulation with lipopolysaccharides (for IL-1) or phytohaemagglutinin A (PHA) (for IL-2 and IFN), they produced IL-1 and IFN in amounts similar to those produced by normal lymphocytes, but only modest levels of IL-2. These results indicated that proliferating LGL, like normal LGL, have a secretory capacity. The lack of constitutive lymphokine production, the lack of Tac receptor expression, and the defect in IL-2 production after PHA stimulation do not support the hypothesis of an autocrine proliferation sustained by a known growth factor.

Adult↗
PubMed1986

Large granular lymphocyte/natural killer cell proliferative disease: clinical and laboratory heterogeneity.

6 patients with a chronic, clinically heterogeneous proliferative disorder of the large granular lymphocytes (LGL) were investigated. In each case the majority of peripheral blood lymphocytes reacted with HNK-1, OKT3 and T11 monoclonal antibodies, whereas morphology and other immunological features varied from case to case. 2 cases were of particular interest. 1 patient had an expansion of HNK-1 stained, large agranular rather than granular lymphocytes; another patient's LGL simultaneously expressed HNK-1, OKT4 and T8 antigens. The heterogeneous features of these abnormally expanded cell populations are similar to those of the normal cell subsets from which they are likely to have originated.

Adult↗
PubMed1986

Defective platelet aggregation induced by platelet activating factor in myeloproliferative disorders: deficiency of an aspirin-independent mechanism?

Platelets from 6 out of 10 patients with myeloproliferative disorders showed only a single reversible wave of aggregation when challenged with platelet activating factor (PAF). Preexposure to subthreshold concentrations of adrenaline resulted in a full irreversible response to PAF. Aspirin, however, removed this synergism. In the remaining 4 patients, PAF induced a full response but aspirin abolished the synergism with adrenaline in 2 of them. In platelets from all controls aspirin failed to abolish the synergism between PAF and adrenaline. It is suggested that patients with myeloproliferative disorders lack - to varying degrees - an aspirin-independent mechanism which amplifies the primary response to PAF. Such a mechanism could involve the products of arachidonic acid metabolism catalyzed by lipoxygenase.

Adult↗
PubMed1986

Migratory capacity of large granular lymphocytes from T-gamma-lymphoproliferative disorders.

We have investigated 10 patients with T gamma-lymphoproliferative disorders (T gamma LPD) for cell migratory capacity. Large granular lymphocytes (LGLs) expanding in these subjects expressed natural killer cell markers (HNKI, B73.1, AB8.28, N901, OKM1) to a variable extent. The patients' LGLs mediated antibody-dependent cellular cytotoxicity, while appreciable natural killer activity was only measurable in 3 patients. The migratory capacity of T gamma LPD was examined by using nitrocellulose filters. The patients' LGLs migrated into filters and showed responsiveness (in 9 of 10 patients) to activated serum, used as chemoattractant, as normal LGLs do. No clearcut correlation emerged between in vitro migratory capacity and disease aggressiveness or involvement of abdominal organs. These results confirm in T gamma LPD the migratory potential of LGLs and suggest the possibility that acquisition of enhanced locomotor capacity is not a crucial determinant of disease aggressiveness in T gamma LPD.

Adult↗
PubMed1985

T cell receptor beta chain gene rearrangements in lymphoproliferative disorders of large granular lymphocytes/natural killer cells.

Twelve cases of T gamma LPD (lymphoproliferative disorders of Fc gamma receptor-bearing T cells) involving an expansion of large granular lymphocyte/natural killer (LGL/NK) cells were investigated for the expression of LGL/NK-associated markers and for T beta gene rearrangement. All the cases selected were classified as T gamma LPD on the basis of morphology, function, and phenotype of the circulating cells. 10 to 12 cases displayed clonal rearrangements of the T beta locus and expression of the T3 antigen, whereas the 2 remaining cases displayed the germline configuration of the T beta gene and no expression of the T3 antigen. T8, Mol, B73.1, and N901 antigens were variably expressed among both T beta+T3+ and T beta-T3- T gamma LPD cases. We suggest that individual T gamma LPD cases represent the clonal expansion of cells frozen at different stages of differentiation/activation within an individual hematopoietic LGL/NK lineage.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1985

Fibrinogen Bergamo I (A alpha 16Arg----Cys): susceptibility towards thrombin following aminoethylation, methylation or carboxamidomethylation of cysteine residues.

An abnormal fibrinogen, denoted as "fibrinogen Bergamo I", has been characterized. Its defect consists in an exchange of arginine by cysteine in position 16 of the A alpha-chain, thus corresponding to that found in a number of other fibrinogen variants. The abnormal fibrinopeptide A cannot be split off by thrombin from intact fibrinogen Bergamo I. We describe three different chemical modifications of the cysteine A alpha 16, i.e. aminoethylation, methylation and carboxamidomethylation, and their effects on the susceptibility of fibrinogen Bergamo I towards thrombin attack. S-aminoethylation of the A alpha 16Cys renders the peptide bond A alpha 16-17 cleavable by thrombin. Following methylation or carboxamidomethylation, the A alpha 19-arginyl bond becomes accessible for thrombin. The chemically modified extended fibrinopeptide A can be readily separated from the normal fibrinopeptide A by HPLC. The latter two modifications are suitable alternative procedures for detecting the molecular defect A alpha 16Arg----Cys of fibrinogen.

Amino Acids↗
PubMed1985

Interaction between a serum factor and T lymphocytes in Gaucher disease.

A defective formation of E rosette from peripheral lymphocytes was observed in five patients with Gaucher disease. Evidence is shown that the reduction of E rosetting capacity is due to serum factors since it was induced in normal lymphocytes incubated with patients' sera. It is likely that ferritin, found elevated in the patients, might be involved in this inhibitory phenomenon. This disfunction might play a role in the high incidence of cancer in Gaucher patients.

Adult↗
PubMed1985

Purification of antithrombin 'Vicenza': a molecule with normal heparin affinity and impaired reactivity to thrombin.

Antithrombin III (AT) 'Vicenza', a previously described dysfunctional AT associated with familial thrombosis, has been isolated by heparin affinity chromatography. The purified molecule has been investigated by SDS-polyacrylamide gel electrophoresis and crossed immunoelectrophoresis after incubation with different amounts of thrombin. A normal affinity for heparin has been demonstrated. However, evidence is produced that AT 'Vicenza' poorly inhibits thrombin. Present data suggest that AT 'Vicenza' consists of a population of two molecules, half of which does not form a complex with thrombin however and loses its heparin affinity upon thrombin treatment.

Antithrombin III↗
PubMed1985

Platelet 5-hydroxytryptamine transport and storage in myeloproliferative disorders.

Platelets of patients with myeloproliferative disorders (MD) such as polycythaemia vera (PV), chronic myelogenous leukaemia (CML), idiopathic myelofibrosis (IM) and essential thrombocythaemia (ET) have been found to have low 5HT levels measured both by a fluorimetric and a liquid chromatographic assay. Km and Vmax for platelet active uptake of 3H-5HT were not significantly different in controls and patients. Inhibition of 5HT reuptake by imipramine or induction of moderate release by fenfluramine were not sufficient to distinguish the group of MD platelets from controls, although some patients had less of a tendency to retain intraplatelet amine. The low platelet 5HT content found in our patients seems not to be the consequence of disturbed active transport of 5HT across platelet membrane. Although defective storage of this amine within the cell is probable, the results of the present study do not rule out the possibility that platelets from MD patients undergo in vivo activation by endogenous stimuli not inhibited by aspirin. 10 d treatment with aspirin did not result in any significant rise in intraplatelet 5HT concentration.

Adult↗