Olivier Levillain

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As in human disease, macrophages (MØ) are central players in the development and progression of experimental atherosclerosis. In this study we have evaluated the phenotype of MØ associated with progression of atherosclerosis in the apolipoprotein E (ApoE) knockout (KO) mouse model.We found that bone marrow-derived MØ submitted to M1 and M2 polarization(More)
Arginine production was measured in isolated rat nephron segments. Segments were incubated with 0.3 mM aspartate and 0.1 mM L-[ureido-14C]-citrulline in a sealed chamber. Arginase and urease were added to the medium to hydrolyze arginine and to release 14CO2, which was trapped in KOH and counted. Arginine synthesis was found only in the proximal tubule,(More)
Renal arginase activity is a potent source of ornithine (Orn) for polyamine synthesis. Ornithine decarboxylase (ODC) was localized along the mouse and rat nephron by incubating viable nephron segments isolated by microdissection from collagenase-treated kidneys with or without D,L-2-(difluoromethyl)ornithine (DFMO), a selective inactivator of ODC. Tubules(More)
Hydrolysis of arginine into urea and ornithine (Orn) was observed to take place in several segments of the rat nephron including cortical and medullary pars recta of the proximal tubule (PST) and collecting duct (CD). This work was now extended to the adult mouse and rabbit. Representative nephron segments, obtained by microdissection of collagenase-treated(More)
Urea production from arginine was studied in vitro in the kidney of normal rats in tubule suspensions of the four different renal zones (cortex, outer and inner stripe of outer medulla, and inner medulla), and in individual microdissected nephron segments. Tissue was incubated with L-[guanido-14C]-arginine to measure cellular arginase activity. Addition of(More)
In mammalian kidney, the proximal convoluted tubule (PCT) is the main site of arginine (Arg) production. Arginine can be used in the biosynthesis of guanidino compounds (GC). Since uremic rats have a lower functional mass of PCT, GC synthesis might be modified, especially that of guanidinoacetic acid (GAA) which occurs in PCT. In order to study GC(More)
In the rat kidney, arginine (Arg) synthesis is restricted to the proximal tubule with a decreasing intensity from its convoluted (PCT) to its straight part (PST). The present study was designed to investigate the pattern of Arg synthesis along the nephron in other mammals, the mouse and rabbit. Microdissected representative nephron segments were incubated(More)
Trusted computing has been explored through several international initiatives. Trust in a platform generally requires a subset of its components to be trusted (typically, the CPU, the chipset and a virtual machine hypervisor). These components are granted maximal privileges and constitute the so called Trusted Computing Base (TCB), the size of which should(More)
The enzymes ornithine aminotransferase (OAT) and ornithine decarboxylase (ODC) share L-ornithine as a common substrate and arginase II produces this amino acid. In the murine kidney, testosterone induced ODC gene expression and polyamine production, but it is unknown how OAT gene is expressed under androgen treatment. These experiments were designed to(More)
The kidney is involved in amino acid reabsorption and metabolism; consequently, in renal insufficiency, these important functions are disturbed, as has been reported in animals and patients. In a first experimental series, rats were subjected to degrees of nephrectomy (NX) varying between 10% and 90%. Three weeks later, amino acid levels were measured in(More)