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Biomedical subjects

A Besse

Publications and source records attributed to A Besse.

11 recordsLinked to original sources
PubMed2002

3xP3-EGFP marker facilitates screening for transgenic silkworm Bombyx mori L. from the embryonic stage onwards.

Transgenesis was recently achieved in Bombyx mori L., but it has proved difficult and time-consuming to screen the numerous progeny to identify the transgenic individuals. As the 3xP3-EGFP marker has been shown to be a suitable universal marker for transgenic insects (Nature 402 (1999) 370), we evaluated its use for embryonic-stage screening for B. mori L. germline transformation. Using the piggyBac-derived vector pBac[3xP3-EGFPaf], we were able to isolate four transgenic individuals from about 120,000 embryos (560 broods). The screening was straightforward due to EGFP production in the G1 embryonic stemmata, which was visible through the translucent egg chorion. EGFP was produced in the stemmata and central and peripheral nervous systems from the fifth day of embryonic development. It persisted at high levels in the stemmata throughout the larval stage, and was also present in the compound eyes and nervous tissues of the pupae and the compound eyes of the moths.

Animals↗
PubMed2001

[Hemophagocytosis during multiple organ failure: M-CSF overproduction or viral reactivation?].

OBJECTIVE: This study was aimed to assess the potential role of M-CSF and viral reactivation in the genesis of haemophagocytosis during the multiple organ failure (MOF) syndrome. METHODS: Twenty-five patients (mean age: 60 +/- 16 years; Apache II: 23 +/- 5) sustaining MOF with an unexplained thrombocytopenia were studied. In each patient, a bone marrow aspirate, serum M-CSF concentration, and a virological examination (Herpes viruses) were obtained on admission. In addition, 20 patients (mean age: 57 +/- 15 years; Apache II: 24 +/- 7) with at least two organ failures but no thrombocytopenia constituted the control group. Circulating M-CSF levels and the frequency of virus reactivation were compared between groups. RESULTS: Haemophagocytosis was diagnosed in 11/25 patients (44%). No viral reactivation was found. Serum M-CSF concentrations were higher in the presence of haemophagocytosis (699 +/- 242 vs 438 +/- 157 IU.mL-1; p < 0.05). Ferritin levels were also increased in the presence of a macrophage activation (3,258 +/- 2,807 vs. 520 +/- 280 mg.L-1; p < 0.0001). In contrast, both circulating M-CSF and ferritin levels were similar between thrombocytopenic patients with no hemophagocytosis and controls. CONCLUSIONS: This study confirmed the high incidence of haemophagocytosis in critically ill patients sustaining MOF. In this setting, circulating M-CSF levels were markedly elevated, whereas no Herpes viruses reactivation was found.

Aged↗
PubMed2001

Dag-1 carcinoma cell in studying the mechanisms of progression and therapeutic resistance in bladder cancer.

OBJECTIVE: We describe a new human bladder carcinoma cell line (DAG-1) established from a resected bladder cancer fragment and maintained in culture for more than 5 years and over 300 passages. METHODS AND RESULTS: Immunological, biochemical and molecular analysis showed that the DAG-1 cells (62 chromosomes) express the cytokeratines 8, 13, 18 and 20 that confirm their epithelial origin as well as numerous cytokine and cytokine receptor mRNAs. They secrete tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitors (PAI-1 and PAI-2), and express u-PA receptors (u-PAR/CD87) at their surface. DAG-1 cells are resistant to TNFalpha- and IFNgamma-induced apoptosis, two cytokines secreted in the urine of Calmette-Guérin bacillus-treated patients and involved in the tumor regression. CONCLUSION: The DAG-1 cell line is a useful tool, both in vitro and in vivo, to study the progression of bladder tumors and their mechanisms of resistance to immunotherapy in relation with PAI-2 and antioxidant enzymes.

Aged↗
PubMed2000

Effect of cytokines and growth factors on the macrophage colony-stimulating factor secretion by human bone marrow stromal cells.

We have investigated the effect of growth factors, inflammatory and anti-inflammatory cytokines on the macrophage colony-stimulating factor (M-CSF) secretion by cultured human bone marrow stromal cells. Their production of M-CSF cultured in serum-free medium is enhanced in a time-dependent manner in response to tumour necrosis factor (TNF-)alpha and interleukin (IL-)4 but not to IL-1, IL-3, IL-6, IL-7, IL-10, SCF, granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, bFGF and transforming growth factor (TGF-)beta. The co-addition of IL-4 and TNF-alpha has a greater than additive effect on the secretion of M-CSF suggesting that they act synergistically. The anti-inflammatory molecules IL-10 and TGF-beta have no effect on the TNF-alpha-induced M-CSF synthesis by marrow stromal cells. In conclusion TNF-alpha and IL-4 are potent stimulators of the M-CSF synthesis by human bone marrow stromal cells, a result of importance regarding the role of M-CSF in the proliferation/differentiation of mononuclear-phagocytic cells and the role of marrow stromal cells as regulators of marrow haematopoiesis.

Bone Marrow Cells↗
PubMed2000

Platelet-activating factor acetylhydrolase and haemophagocytosis in the sepsis syndrome.

Sepsis syndrome (SS) is associated with depressed PAF acetylhydrolase, the enzyme responsible for the degradation of platelet activating factor. PAF acetylhydrolase is in a large part produced by macrophages, whose inadequate activation with haemophagocytosis is frequent in patients with SS. The aim of this study was to test the hypothesis that PAF acetylhydrolase levels could be affected in these critically ill patients, because of the large amounts produced by activated macrophages in vitro and in vivo in animal models. The levels of serum PAF acetylhydrolase were assessed in 90 SS patients, who were divided into three groups: patients with (n = 34) or without haemophagocytosis (n = 31), and patients without thrombocytopenia (n = 25) who were used as a control group. The number of organ dysfunctions was matched between patients with haemophagocytosis and controls. Normal reference values were obtained in 59 randomly selected blood donors. Circulating levels of PAF acetylhydrolase were significantly (p = 0.0001) decreased in patients with SS (57+/-3 nmol/ml/min, n = 90) when compared with healthy subjects (69+/-3 nmol/ml/min, n = 59). PAF acetylhydrolase levels were greater in the presence of a haemophagocytosis but without statistical significance (64.2+/-6.5 vs. 50.1+/-2.8:p = 0.25). Despite the fact that macrophagic activation stimulates the in vitro release of PAF acetylhydrolase, no difference was found between patients with or without haemophagocytosis. The mechanism and the role of the PAF acetylhydrolase reduction in SS patients remain to be determined.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1999

Prostaglandin E2 regulates macrophage colony stimulating factor secretion by human bone marrow stromal cells.

Bone marrow stromal cells regulate marrow haematopoiesis by secreting growth factors such as macrophage colony stimulating factor (M-CSF) that regulates the proliferation, differentiation and several functions of cells of the mononuclear-phagocytic lineage. By using a specific ELISA we found that their constitutive secretion of M-CSF is enhanced by tumour necrosis factor-alpha (TNF-alpha). The lipid mediator prostaglandin E2 (PGE2) markedly reduces in a time- and dose-dependent manner the constitutive and TNF-alpha-induced M-CSF synthesis by bone marrow stromal cells. In contrast, other lipid mediators such as 12-HETE, 15-HETE, leukotriene B4, leukotriene C4 and lipoxin A4 have no effect. EP2/EP4 selective agonists (11-deoxy PGE1 and 1-OH PGE1) and EP2 agonist (19-OH PGE2) inhibit M-CSF synthesis by bone marrow stromal cells while an EP1/EP3 agonist (sulprostone) has no effect. Stimulation with PGE2 induces an increase of intracellular cAMP levels in bone marrow stromal cells. cAMP elevating agents (forskolin and cholera toxin) mimic the PGE2-induced inhibition of M-CSF production. In conclusion, PGE2 is a potent regulator of M-CSF production by human bone marrow stromal cells, its effects being mediated via cAMP and PGE receptor EP2/EP4 subtypes.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1999

Interleukin-4 (IL-4), but not IL-10, regulates the synthesis of IL-6, IL-8 and leukemia inhibitory factor by human bone marrow stromal cells.

Leukemia inhibitory factor (LIF), interleukin 6 (IL-6) and IL-8 are important regulators of inflammation and hematopoiesis. Human bone marrow stromal cells regulate marrow hematopoiesis by secreting cytokines. By using reverse-transcriptase polymerase chain reaction (RT-PCR), we demonstrate that human bone marrow stromal cells constitutively express LIF, IL-6 and IL-8 transcripts. By using specific ELISAs, we found that their spontaneous productions of LIF, IL-6 and IL-8 are elevated in response to serum and after stimulation with the pro-inflammatory cytokines IL-1alpha and TNF-alpha. The anti-inflammatory cytokine IL-4 reduces their serum- and cytokine-induced LIF secretion. By contrast, IL-4 stimulates their serum- and IL-1alpha-induced IL-6 synthesis. IL-4 has no effect on the serum-induced IL-8 synthesis by marrow stromal cells, but stimulates their cytokine-induced IL-8 production. The anti-inflammatory cytokine IL-10 has no effect on the serum- and cytokine-induced LIF, IL-6 and IL-8 synthesis by bone marrow stromal cells. RT-PCR experiments reveal the presence of IL-4 receptor alpha-chain mRNA and IL-10 receptor mRNA in cultured bone marrow stromal cells. The differential regulation by IL-4 of two related cytokines, such as LIF and IL-6, and the enhanced effect of this 'anti-inflammatory' cytokine on IL-6 and IL-8 synthesis highlight the tightly controlled regulation and the complexity of the cytokine production within the human bone marrow.

Bone Marrow↗
PubMed1999

Expression of platelet-activating factor receptor transcript-1 but not transcript-2 by human bone marrow cells.

The presence of platelet-activating factor receptor (PAF-R) transcripts 1 and 2 was investigated in human bone marrow cells by a reverse transcriptase polymerase chain reaction (RT-PCR) procedure which detected their simultaneous presence. RT-PCR experiments reveal PAF-R transcript 1 (but not 2) in freshly isolated mononuclear marrow cells, CD34+ hematopoietic stem/progenitor cells and cultured marrow stromal cells. For these experiments, the 5637 human bladder carcinoma cell line is used as a positive control for the presence of PAF-R transcripts 1 and 2. Flow cytometry experiments confirm the presence of PAF-R on marrow stromal cells and CD34+ stem/progenitor cells. In conclusion, the expression of PAF-R transcript 1, which mainly exists in circulating leukocytes, is also found in CD34+ stem/progenitor cells and cells of the marrow microenvironment, strengthening the potential role of PAF during marrow hematopoiesis.

Antigens, CD34↗
PubMedDate not supplied

Is glucose self-monitoring beneficial in non-insulin-treated diabetic patients? Results of a randomized comparative trial.

To study if self-monitoring of glucose, urinary or capillary, could help them to improve their metabolic control through better compliance to diet and/or hypoglycaemic agents, 208 non-insulin-treated poorly controlled diabetic patients were randomized to: group A--regular HbA1c determinations but no self-monitoring, group B--self-urine glucose monitoring, twice every other day, group C--self blood glucose monitoring, twice every other day, and followed six months. At the end of the study period, the decrease of HbA1c over six months--main endpoint--was not significantly different between the three groups (mean +/- SEM; group A: -0.5 +/- 0.2%; group B: -0.1 +/- 0.3%; group C: -0.4 +/- 0.3%). However, the degree of compliance to blood glucose self-monitoring in group C appeared to relate to the outcome: a significant correlation was found between the number of blood glucose strips used and the decrease of HbA1c (r = .36, p less than .02). We conclude that regular self-monitoring has no definite advantage over the usual management for improving metabolic control in non-insulin-treated diabetic patients, though it may possibly help patients ready to comply with its use.

Aged↗