Prostaglandin H-synthase-2 is the main enzyme involved in the biosynthesis of octadecanoids from linoleic acid in human dermal fibroblasts stimulated with interleukin-1beta.

This study was focused on the characterization of the metabolism of linoleic acid by human dermal fibroblasts and the effect of interleukin-1 on the biosynthesis of octadecanoids. Dermal fibroblasts untreated and treated with recombinant IL-1beta were incubated with exogenous labeled linoleic acid. A combination of high performance liquid chromatography and gas chromatography-mass spectrometry was used as the analytic technique.

The uvrB gene of Pseudomonas aeruginosa is not DNA damage inducible.

The uvrB gene of Pseudomonas aeruginosa has been isolated from a genomic library by complementation of an Escherichia coli uvrB mutant. The complete nucleotide sequence of P. aeruginosa uvrB consists of 2,013 bp, encoding a polypeptide of 670 amino acids.

Expression of N-CAM (CD56) on acute leukemia cells: relationship with disease characteristics and outcome.

Expression of CD56 was analyzed by indirect immunofluorescence method on bone marrow samples from 94 newly diagnosed patients with acute leukemia (AL), including 59 acute myelogenous leukemias (AML) and 35 acute lymphoblastic leukemias (ALL). CD56 was expressed on 17 +/- 18% (range: 0-72%) of AML cells and 24 +/- 24% (range: 0-98%) of ALL cells, without significant differences between FAB subtypes in AML, nor immunologic subtypes in ALL. Expression of CD56 was not associated with any clinical or biological characteristic at diagnosis, nor with prognosis in AML or ALL.

Interleukin-1 enhances the ability of cultured human umbilical vein endothelial cells to oxidize linoleic acid.

Human umbilical vein endothelial cells (HUVEC) were treated with recombinant interleukin (IL)-1 beta, and the metabolism of exogenous linoleic acid was studied. High performance liquid chromatography, gas chromatography-mass spectrometry, and chiral analysis revealed that HUVEC enzymatically convert linoleic acid mainly into 13-(S)hydroxy-9(Z),11(E)-octadecadienoic (13-HODE) and 9-(R)hydroxy-10(E),12(Z)-octadecadienoic acids, which may isomerize toward all-trans compounds. IL-1 beta increased the formation of all octadecanoids in a time- and dose-dependent manner with similar EC50 (approximately 1 unit/ml).

Expression of VLA molecules on acute leukemia cells: relationship with disease characteristics.

VLA molecules are involved in the adhesion of hematopoietic cells to the bone marrow stroma and play a role in the mediation of cellular interactions and migrations that are potentially important in the biology of acute leukemia (AL). We studied the expression of VLA-2 (CD49b), VLA-4 (CD49d), and VLA-5 (CD49e) by indirect immunofluorescence on leukemic cells from 67 patients with acute myelogenous leukemia (AML) and 40 patients with acute lymphoblastic leukemia (ALL). VLA-2, VLA-4, and VLA-5 were expressed, respectively, on 13 +/- 17%, 33 +/- 29%, and 36 +/- 30% of AML cells with 20, 54 and 61% positive cases and on 22 +/- 27%, 40 +/- 30%, and 39 +/- 29% of ALL cells with 29, 60, and 61% positive cases.

Expansion of mycobacterium-reactive gamma delta T cells by a subset of memory helper T cells.

Human gamma delta T cells expressing the V gamma 9/V delta 2 T-cell receptor have been previously found to proliferate in response to certain microorganisms and to expand throughout life, presumably because of extrathymic activation by foreign antigens. In vitro expansion of V gamma 9/V delta 2 cells by mycobacteria has been previously shown to be dependent on accessory cells. In order to gain an insight into the mechanisms involved in the expansion of these cells, we have undertaken to identify the peripheral blood subset of cells on which proliferation of V gamma 9/V delta 2 cells in response to mycobacteria is dependent.

Characterization of arachidonic acid metabolites through the 12-lipoxygenase pathway in human epidermis by high-performance liquid chromatography and gas chromatography/mass spectrometry.

Fragments of human epidermis were incubated in the presence of exogenous arachidonic acid. The incubates were subjected to reversed-phase and straight-phase high-performance liquid chromatography and finally the identity of the arachidonic acid metabolites of the 12-lipoxygenase pathway was determined by means of gas chromatography/mass spectrometry. It was found that human epidermis produces 8-hydroxy-11,12-epoxy- and 10-hydroxy-11,12-epoxyeicosatrienoic acid, 8,9,12-, 8,11,12- and 10,11,12-trihydroxyeicosatrienoic acid, 12-keto-eicosatetraenoic acid and 12-hydroxy-eicosatetraenoic acid derived from arachidonic acid via the 12-lipoxygenase pathway.

Interleukin-1 increases 15-hydroxyeicosatetraenoic acid production in human dermal fibroblasts.

Inhibition of the formation of pro-inflammatory eicosanoids such as leukotrienes and 12-hydroxyeicosatetraenoic acid by 15-hydroxyeicosatetraenoic acid (15-HETE) has been reported. Psoriatic dermis synthesizes reduced levels of 15-HETE and it has been postulated to play a role in the pathophysiology of this disease. Interleukin-1 stimulates the production of prostaglandin E2 in fibroblasts, but its effect on the synthesis of 15-HETE is at present unknown.

Potential role for non-HLA-restricted cytotoxic cells in the immune surveillance of acute leukemia.

The observation of more frequent leukemias in immune deficiencies of the non-HLA-restricted cytotoxic cell system and the participation of this system in the anti-leukemic effect of allogeneic bone marrow transplantation in acute leukemia indicate that these cells might play a role in the immune surveillance against leukemia. In order to find more direct evidence of this role we studied the susceptibility of leukemic cells to lysis by non-HLA-restricted cytotoxic cells, the functional value of these cells in leukemic patients in complete remission (CR), and expression by leukemic cells of adhesion molecules CD54 and CD58, which play a role in the adherence between cytotoxic cells and their targets. Our results are concordant to confirm a potential role of non-HLA-restricted cytotoxic cells in the immune surveillance of acute leukemia based on increased relapse rate in acute myeloid leukemia patients with no inducible lymphokine-activated killer (LAK) cell activity during CR, short survival of acute lymphoblastic leukemia patients whose blast cells are resistant to lysis by LAK cells, and poor overall prognosis of leukemias which do not express CD58.

MHC-independent presentation of mycobacteria to human gamma delta T cells.

The majority of human peripheral gamma delta T cells express antigen receptors using the V gamma 9 and V delta 2 gene products. Cells of this subset have been previously shown to uniformly recognize mycobacteria regardless of their V-(D)-J junctional sequences in an MHC-unrestricted manner. This reactivity superficially resembles activation of alpha beta cells by bacterial superantigens, which are thought to be presented by monomorphic regions of MHC class II molecules.

Interleukin-1 increases 15-hydroxyeicosatetraenoic acid formation in cultured human endothelial cells.

Interleukin 1 (IL-1) induces prostanoid biosynthesis in endothelial cells by promoting cyclooxygenase expression, but little is known about its activity on the biosynthesis of hydroxyeicosatetraenoic acids (HETEs). We studied the effect of human recombinant IL-1 beta on the conversion of arachidonic acid (AA) to 15-HETE, a powerful inhibitor of the biosynthesis of proinflammatory eicosanoids. Cultured human umbilical vein endothelial cells were incubated with or without IL-1 beta prior to the addition of labeled AA.

Effects of linoleic and oleic acid anilides on prostacyclin synthesis and fibrinolytic profile of human endothelial cells in culture: relevance to the toxic oil syndrome.

We evaluated the effects of fatty-acid anilides (FAA) on prostacyclin (PGI2) synthesis and on the fibrinolytic properties of human umbilical vein endothelial cells. Preincubation of endothelial cells with oleic- and linoleic-anilides (OAA and LAA, respectively) resulted in a time- and concentration-dependent inhibition of ionophore A23187- and thrombin-induced PGI2 synthesis. However, no significant effects of FAA on arachidonic acid-induced PGI2 synthesis were found, except with 1000 microM LAA which inhibited cyclooxygenase activity after 24 h.

Influence of fatty acid anilides present in toxic oils on the metabolism of exogenous arachidonic acid in cultured human endothelial cells.

The effect of fatty acid anilides (FAA) on the exogenous arachidonic acid (AA) metabolism and toxicity of isolated human endothelial cells was studied to clarify their possible role in the etiology of toxic oil syndrome. Confluent cells were incubated with and without linoleic acid anilide (LAA), oleic acid anilide (OAA) and two unrelated samples for 2-24 h prior to the addition of [l-14C]AA alone or with calcium ionophore A-23187. The eicosanoids produced were analyzed by RP-HPLC.

Epidermal cell-polymorphonuclear leukocyte cooperation in the formation of leukotriene B4 by transcellular biosynthesis.

The cellular origin of Leukotriene B4, a potent pro-inflammatory agent that is present in psoriatic lesions, has not been completely ascertained. The present study was performed in order to assess the possible contribution of epidermal cells to leukotriene B4 synthesis through 5-lipoxygenase or by means of transcellular metabolism of the epoxide intermediate leukotriene A4 from activated polymorphonuclear leukocytes. The metabolism of exogenous arachidonic acid in fresh human epidermal cell, polymorphonuclear leukocyte or mixed suspensions was determined by means of high-performance liquid chromatography.

Dual antigenic recognition by cloned human gamma delta T cells.

The function of gamma delta T cells is still elusive. The nature of the antigens that they recognize and the mode of presentation of these antigens are largely unknown. The majority of human peripheral gamma delta T cells bear a V gamma 9/V delta 2 T cell receptor, and display nonclonal reactivity to mycobacteria, without restriction by MHC.

Cyclooxygenase activity is increased in platelets from psoriatic patients.

The aim of the present study was to ascertain the relationship between in vitro hyper-aggregability and alterations in arachidonic acid metabolism in platelets from psoriatic patients. We have studied the response to several concentrations of ADP, collagen, and arachidonic acid of intact platelets from psoriatic patients and normal subjects, with and without irreversible inhibition of platelet cyclooxygenase by aspirin. Apparent kinetic constants (apparent Michaelis constant [Km] and apparent maximum velocity [Vmax]) of cyclooxygenase in platelets from both controls and psoriatic patients were also studied.

Metabolism of exogenous arachidonic acid by polymorphonuclear leukocytes from psoriatic patients.

We evaluated the metabolism of exogenous arachidonic acid in polymorphonuclear leukocytes from psoriatic patients in comparison with those from normal subjects. The leukocytes were incubated with 10 microM labelled arachidonic acid and 5 microM A23187 for varying periods of time. We evaluated all the compounds derived from the 5-lipoxygenase activity, including the products of non-enzymatic transformation of leukotriene A4 and w-oxidized leukotriene B4.

In vitro effects of recombinant hemopoietic growth factors on progenitor cells from patients with myelodysplastic syndromes.

The effects of four recombinant hemopoietic growth factors (HGF) and of the impure factor HTB9 on proliferation and maturation of marrow myeloid (CFU-GM) and erythroid (BFU-E) progenitor cells were studied in 22 cases of myelodysplastic syndromes (MDS). In most cases, IL-3, GM-CSF and G-CSF increased significantly the number of myeloid colonies, the best combination being IL-3 + GM-CSF. A significant increase in the myeloid colony/cluster ratio was also noted, but cytological examination of colony cells showed little maturation.

Myelodysplastic syndromes: a study of surface markers and in vitro growth patterns.

A study of surface markers and in vitro growth in semi-solid and liquid medium was performed in 35 patients with newly diagnosed myelodysplastic syndrome (MDS). Surface markers were studied by CD34, CD13, CD14, CD15, and CD33 monoclonal antibodies. There was no strict correlation with the FAB typing, but CD34 was expressed only in refractory anemia with excess of blasts (RAEB) or RAEB in transformation (RAEB-t).

Correlations between cytogenetics and morphology in myelodysplastic syndromes.

In order to detect possible relationships between cytogenetic abnormalities and morphologic features in myelodysplastic syndromes (MDS), 48 patients with MDS were investigated. Clonal cytogenetic abnormalities were present in bone marrow cells from 27 patients (56%). The most frequent single anomaly was del (5 q) (10 cases), followed by monosomy 7 (3 cases), trisomy 8 (3 cases) and del (20 q) (2 cases).

Fibrinogen Barcelona II: a new case of A alpha 16 Arg----His substitution.

We describe a new congenital dysfibrinogenemia: fibrinogen Barcelona II in 8 members of a family with no major bleeding or thrombotic tendency. Incubation of this fibrinogen with thrombin at low concentration releases half of the expected normal fibrinopeptide A (FPA) and with some delay it releases an abnormal FPA. Abnormal FPA was purified and sequenced and showed a change in the normal amino acid sequence: arginine in position 16 has been substituted by a histidine.

Exogenous arachidonic acid metabolism in platelets from psoriatic patients.

Several reports have been published on platelet hyperaggregation in psoriatic patients, which might be related to alterations in arachidonic acid (AA) metabolism by platelets. We have studied the AA metabolism pattern, total eicosanoid formation and biosynthesis rate in platelet from psoriatic patients and from normal subjects after incubation with exogenous AA. We have found no difference in the metabolic pattern of platelets.

[Kinetics of eicosanoid formation in human epidermal cells in suspension].

Increased levels of eicosanoids in lesions of psoriasis suggest activation of arachidonic acid metabolism in different cell types play a physiopathologic role. The contribution of each cell type present in psoriasis has been the subject of some controversy, which has led us to study the metabolism of arachidonic acid in human epidermal cells suspensions. 12-HETE was found to be the main product, followed by PGE2 and PGF2 alpha; no 5-lypoxygenase products were found.