References of "Franssen, Christine"
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See detailLAB’INSIGHT « Toxicological Risk Assessment » - Input of ULg preclinical studies
Drion, Pierre ULg; Remy, Benoît ULg; Winandy, Marie ULg et al

Scientific conference (2013, October 24)

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See detailDescription of a new species, Bifidobacterium crudilactis sp. nov., isolated from raw milk and raw milk cheeses.
Delcenserie, Véronique ULg; Gavini, Françoise; Beerens, Henri et al

in Systematic & Applied Microbiology (2007), 30(5), 381-9

A new Bifidobacterium species is described based on the study of ten Gram-positive strains with fructose-6-phosphate phosphoketolase activity. They are part of a phenotypic group comprising 141 strains ... [more ▼]

A new Bifidobacterium species is described based on the study of ten Gram-positive strains with fructose-6-phosphate phosphoketolase activity. They are part of a phenotypic group comprising 141 strains isolated from raw milk and raw milk cheeses in French raw milk cheese factories. This group was separated by a numerical analysis based on API 50CH, API 32A tests and growth at 46 degrees C. A strong similarity of 16S rRNA sequences (99.8%) was shown between strain FR62/b/3(T) and Bifidobacterium psychraerophilum LMG 21775(T). However, low DNA-DNA relatedness was observed between their DNAs (31%). The new isolates are able to grow at low temperatures (all ten strains up to 5 degrees C) and strain FR62/b/3(T) grows under aerobic conditions, as does B. psychraerophilum. However, contrary to B. psychraerophilum, they do not ferment L-arabinose, D-xylose, arbutin or melezitose, but they do acidify lactose. The DNA G+C content of FR62/b/3(T) is 56.4mol%. Therefore, the name Bifidobacterium crudilactis sp. nov. is proposed, with its type strain being FR62/b/3(T) (=LMG 23609(T)=CNCM I-3342(T)). [less ▲]

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See detailThe kinetic properties of the carboxy terminal domain of the Bacillus licheniformis 749/I BlaR penicillin-receptor shed a new light on the derepression of beta-lactamase synthesis
Duval, Valérie; Swinnen, Marc; Lepage, Sophie et al

in Molecular Microbiology (2003), 48(6), 1553-1564

To study the properties of the BlaR penicillin-receptor involved in the induction of the Bacillus licheniformis beta-lactamase, the water-soluble carboxy terminal domain of the protein (BlaR-CTD) was ... [more ▼]

To study the properties of the BlaR penicillin-receptor involved in the induction of the Bacillus licheniformis beta-lactamase, the water-soluble carboxy terminal domain of the protein (BlaR-CTD) was overproduced in the periplasm of Escherichia coli JM105 and purified to protein homogeneity. Its interactions with various beta-lactam antibiotics were studied. The second-order acylation rate constants k(2)/K' ranged from 0.0017 to more than 1 muM(-1) s(-1) and the deacylation rate constants were lower than 4x10(-5) s(-1) . These values imply a rapid to very rapid formation of a stable acylated adduct. BlaR-CTD is thus one of the most sensitive penicillin-binding proteins presently described. In the light of these results, the kinetics of beta-lactamase induction in Bacillus licheniformis were re-examined. When starting with a rather high cell density, a good beta-lactamase substrate such as benzylpenicillin is too sensitive to beta-lactamase-mediated hydrolysis to allow full induction. By contrast, a poor beta-lactamase substrate (7-aminocephalosporanic acid) can fully derepress beta-lactamase expression under conditions where interference of the antibiotic with cell growth is observed. These results suggest that acylation of the penicillin receptor is a necessary, but not sufficient, condition for full induction. [less ▲]

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See detailDiaspirin Crosslinked Hemoglobin (Dclhb): Absence of Increased Free Radical Generation Following Administration in a Rabbit Model of Renal Ischemia and Reperfusion
Pincemail, Joël ULg; Detry, Olivier ULg; Philippart, C. et al

in Free Radical Biology & Medicine (1995), 19(1), 1-9

In control rabbits, a renal ischemia of 60 min followed by 10 min of reperfusion resulted in an enhanced free radical production in cortical tissue, as assessed by a significant decrease of free ... [more ▼]

In control rabbits, a renal ischemia of 60 min followed by 10 min of reperfusion resulted in an enhanced free radical production in cortical tissue, as assessed by a significant decrease of free glutathione (42%), protein-bound GSH (17%), and vitamin E (49%). In contrast, catalase or glutathione peroxidase activities were not affected by these experimental conditions. Free radical production in this model was also measured directly using electron spin resonance (ESR) spectroscopy associated with a PBN (alpha-phenyl N-tert-butyl-nitrone) spin trap agent in the venous blood arising from the ischemic kidney. The signal consisted of a triplet of doublets. In contrast, no signal could be detected in control blood samples taken prior to inducing ischemia. The burst of free radical production occurred in the early phase after restoration of flow in the kidneys rendered ischemic, as evidenced by a signal of weak intensity which generally appeared within the third minute after reperfusion and progressively increased to form a well-defined asymmetric signal following 10 min of reperfusion. The precise nature of free radicals trapped by the PBN agent remains, however, to be elucidated, but analysis of the coupling constants (aN = 14.5-15 G; a beta H = 2.5-3 G) and asymmetry of the central doublets suggests that the ESR signal may arise from a nitorxy-radical adduct resulting from the spin trapping by PBN of both oxygen- or carbon-centered radicals of lipid origin. As evidenced by both direct and indirect measurements, exchange of rabbit blood immediately after inducing renal ischemia with 30 ml/kg of Diaspirin Crosslinked Hemoglobin (7.5 g/dl in lactated electrolyte) or human serum albumin (7.5 g/dl in lactated electrolyte) did not exacerbate free radical production mediated by an ischemia reperfusion phenomenon, a typical situation found in a resuscitation setting. [less ▲]

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See detailPreservation of Cortical Microcirculation after Kidney Ischemia-Reperfusion: Value of an Iron Chelator
Defraigne, Jean-Olivier ULg; Pincemail, Joël ULg; Detry, Olivier ULg et al

in Annals of Vascular Surgery (1994), 8(5), 457-67

Treatment of suprarenal aneurysms and renal artery reconstructions are both responsible for normothermic ischemia of the kidney (during clamping) followed by reperfusion (declamping). During reflow ... [more ▼]

Treatment of suprarenal aneurysms and renal artery reconstructions are both responsible for normothermic ischemia of the kidney (during clamping) followed by reperfusion (declamping). During reflow through an organ undergoing ischemia the production of free radicals can be associated with cell injury and a no-reflow phenomenon characterized by perfusion defects after a period of transient hyperemia. The objectives of this study were to demonstrate the existence of this phenomenon in the kidney undergoing ischemia followed by reperfusion and to test the potential protection afforded by an iron chelator (desferrioxamine) since free radical reactions are catalyzed by iron. Adult New Zealand white rabbits were divided into the following three groups: group A, 15 minutes of ischemia plus 10 minutes of reperfusion; group B, 60 minutes of ischemia plus 10 minutes of reperfusion; and group C, 60 minutes of ischemia plus 10 minutes of reperfusion combined with infusion of desferrioxamine (50 mg/kg). Cortical microcirculation in the kidney was measured by laser Doppler flowmeter before ischemia and 1, 5, and 10 minutes after reperfusion. Vitamin E content was determined in the cortex of the left kidney after 10 minutes of reperfusion and compared with that of the right (control) kidney. After 1 minute of reperfusion the cortical microcirculatory flow was significantly increased in all three groups (reactive hyperemia). In groups A and C blood flow returned to preclamping values after 10 minutes of reperfusion; however, blood flow in group B remained significantly reduced (29.2% +/- 10.5%) after 5 minutes of reperfusion with a further reduction to 48.5% +/- 5.7% after 10 minutes. These findings were correlated with the dosage of vitamin E since the vitamin E content was greatly reduced by 46.7% +/- 7.8% in group B but did not change significantly in groups A and C. This study shows that 60 minutes of normothermic ischemia is followed by a significant reduction in cortical microcirculatory flow (no-reflow phenomenon). Infusion of an iron chelator (desferrioxamine), however, which decreases the intensity of lipid peroxidation induced by the free radicals, preserves the microcirculatory flow. [less ▲]

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See detailDirect Evidence of Free Radical Production after Ischaemia and Reperfusion and Protective Effect of Desferrioxamine: Esr and Vitamin E Studies
Defraigne, Jean-Olivier ULg; Detry, Olivier ULg; Pincemail, Joël ULg et al

in European Journal of Vascular Surgery (1994), 8(5), 537-43

After surgical renal revascularisation, warm renal ischaemia due to renal artery cross-clamping contributes to postoperative renal dysfunction. After reperfusion, free radicals are thought to be a ... [more ▼]

After surgical renal revascularisation, warm renal ischaemia due to renal artery cross-clamping contributes to postoperative renal dysfunction. After reperfusion, free radicals are thought to be a significant cause of injury. Nevertheless, indisputable proof of free radical production is scarce, partly because of their transient nature. In this study, electron paramagnetic resonance and vitamin E levels were used to demonstrate the free radical production after renal ischaemia and reperfusion. Rabbit kidneys were submitted either to 15 or 60 minutes of ischaemia followed by reperfusion. A spin trap agent (alpha-phenyl-N-tert-butyl nitrone (PBN), 20mg/ml, 1 ml/min) was infused during reperfusion directly into the left renal artery via an aortic catheter before declamping. Blood samples were selectively drawn from the left renal vein for ESR analysis (Varian spectrometer E109) of lipidic residues extracted from blood samples. The vitamin E content of the left renal cortex was determined by HPLC procedure. The right renal cortex was used as a control for the vitamin E values. In the venous effluent, ESR analysis revealed the formation of a spectrum consisting of a triplet of asymmetric doublets. This signal resulted from the spin trapping by PBN of a mixture of both oxygen- and carbon- centred lipidic radicals. The amplitude of the signal which is proportional to the amount of free radicals was significantly higher after 60 minutes ischaemia than after 15 minutes.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

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See detailEvidence for Free Radical Formation During Human Kidney Transplantation
Pincemail, Joël ULg; Defraigne, Jean-Olivier ULg; Franssen, Christine ULg et al

in Free Radical Biology & Medicine (1993), 15(3), 343-8

Fourteen patients undergoing kidney transplantation were studied for evidence of the production of free radicals as assessed by the measurement of vitamin E (an index of lipid peroxidation) and of ... [more ▼]

Fourteen patients undergoing kidney transplantation were studied for evidence of the production of free radicals as assessed by the measurement of vitamin E (an index of lipid peroxidation) and of myeloperoxidase (a marker of neutrophil activation) in the systemic blood. Early (2 min) and late revascularization (30 min) of the kidney were respectively associated with a significant decrease of 35.5 and 40% of the initial level of plasma vitamin E. This consumption paralleled to the decrease of the vitamin E/total lipids ratio, a better indicator of vitamin E status. Heparin administration preceding renal artery clamping resulted in a twofold significant increase of baseline plasma myeloperoxidase (MPO) level (523 +/- 214 ng/ml). At kidney reperfusion, MPO concentration rose again and reached a maximum value of 1,653 +/- 882 ng/ml, indicating the presence of considerable neutrophil activation. A return to the baseline value was observed after 30 min of reperfusion. A short discussion about the possible origin of this MPO increase is given. Taken together, these data strongly suggest that free radical production, leading to lipid peroxidation phenomena, can occur within the early phase of kidney revascularization. Preliminary data using electron spin resonance with the spin-trapping technique strengthen this hypothesis. [less ▲]

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See detailIntérêt de la différence aterio-veineuse en O2 dans l'approche thérapeutique de l'hypertension intracrânienne post-traumatique
Franssen, Christine ULg; Hans, Pol ULg; Deprez, Josette ULg et al

in Agressologie : Revue Internationale de Physio-Biologie et de Pharmacologie Appliquées aux Effets de l'Agression (1991), 32(6-7), 366-368

Elevated intracranial pressure (ICP) is undoubtedly a determinant factor of outcome in severe head injured patient. Until now, medical treatment of elevated ICP in diffuse brain lesions consisted of ... [more ▼]

Elevated intracranial pressure (ICP) is undoubtedly a determinant factor of outcome in severe head injured patient. Until now, medical treatment of elevated ICP in diffuse brain lesions consisted of hyperventilation, CSF drainage, mannitol and barbiturates without accurate selection criteria. In fact, in comatose patients, the cerebral blood flow (CBF) can vary independently of the cerebral metabolic rate of oxygen (CMRO2) which is typically reduced. The venous oxygen saturation (SjO2) measured in the jugular bulb and the arterial-jugular oxygen difference (ajDO2) can be used for more appropriately selecting therapeutic measures. According to the following equation: CMRO2 = CBF x ajDO2, the measurement of the changes in ajDO2 might serve as an indicator of CBF adequacy, out of the presence of cerebral ischemia. A decreased ajDO2 suggests that CBF is excessive for cerebral metabolic requirements and an elevated ajDO2 indicates a decreased CBF. Consequently, treatment of elevated ICP in the presence of a low ajDO2 should be more oriented towards moderate hyperventilation and administration of metabolic depressive agents with maintenance of normal arterial blood pressure. Conversely, in case of high ajDO2, ICP control should aim to increase CBF by maintaining normocapnia, improving hemodynamic status or reducing extravascular volume accordingly. [less ▲]

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