Abstract An HPLC method and a microbiological assay developed for measuring amoxicillin in calf p... more Abstract An HPLC method and a microbiological assay developed for measuring amoxicillin in calf plasma were used in pharmacokinetic studies of the β-lactam antibiotic following intramuscular administration of the test compound. Collected samples were concomitantly ...
Gold nanoparticles (AuNP) hold great potential for biomedical applications. This study was aimed ... more Gold nanoparticles (AuNP) hold great potential for biomedical applications. This study was aimed at examination of the effect of AuNP coating on the redox status of their environment. Two kinds of AuNP were tested, similar by shape and size, but with different surface coatings: either stabilized with citrate or functionalized with dihydrolipoic acid (Au@DHLA NP). Interestingly, whereas citrate-stabilized AuNP interact in vitro with reduced glutathione (GSH) and S-nitrosoglutathione, Au@DHLA NP do not interfere with both biomolecules. Albumin exhibits higher affinity toward citrate-stabilized AuNP than Au@DHLA NP, increasing their hydrodynamic diameter (8.0- and 1.3-fold, respectively). Furthermore, the AuNP coating affects also their internalization by macrophages (which was two fold higher for citrate-stabilized AuNP), following an exposure to a subtoxic NP concentration (10 nM, 80% viability). Citrate-stabilized AuNP were found to decrease the intracellular GSH level (ca. 20%), with no increase in reactive oxygen species production. Furthermore, these AuNP did not induce apoptosis (as shown by caspase-3 activity and nfkb2 transcription factor), and also did not activate gene expression related to oxidative stress (ncf1) and inflammatory response (tnfα). The present data highlight that the functionalization of AuNP with DHLA decreases their reactivity with biomolecules and cells, resulting in a promising medical platform.
... Agenda setting (Streck 2002b60. Streck, C. 2002b. Global public policy networks as coalition... more ... Agenda setting (Streck 2002b60. Streck, C. 2002b. Global public policy networks as coalitions for change. In ... View all references; Streck 2002b60. Streck, C. 2002b. Global public policy networks as coalitions for change. In ...
Abstract Menthol glucoronide was measured in the presence of borneol glucuronide as internal stan... more Abstract Menthol glucoronide was measured in the presence of borneol glucuronide as internal standard by a high-performance liquid chromatography method including a prec-column derivatization step. The carboxylic group of glucuronic acid conjugates was ...
We have studied the pharmacokinetics of tiopronin and its principal metabolite, 2-mercaptopropion... more We have studied the pharmacokinetics of tiopronin and its principal metabolite, 2-mercaptopropionic acid (2-MPA) in healthy volunteers after the oral administration of 500 mg (2 Acadione tablets), followed by simultaneous assay of the two compounds in plasma over a period of 48 h using a new method (emission of fluorescence after HPLC and post-column derivatization by pyrene-maleimide). The absorption of tiopronin was slow (tmax between 4 and 6 h) and the plasma concentrations subsequently fell biexponentially. The principal metabolite 2-MPA appeared later in the plasma (tmax between 10 and 12 h after a lag-time of 3 h) then disappeared monoexponentially. About 15% of the tiopronin was metabolized to 2-MPA.
A method for the assay of various forms of glutathione in human plasma has been developed. The re... more A method for the assay of various forms of glutathione in human plasma has been developed. The reduced form was measured after direct injection of deproteinized plasma with perchloric acid. The unbound oxidized forms were assayed in deproteinized plasma ...
A simple, fast, sensitive method for determination of amikacin in dog plasma using high-performan... more A simple, fast, sensitive method for determination of amikacin in dog plasma using high-performance liquid chomatography (HPLC) is described. A 10 % (w/v) trichloroacetic acid solution was used to deproteinate plasma. After centrifugation of the sample, a 100 μ.1 aliquot of supernatant was directly injected onto the chromatograph. HPLC conditions consisted of an ion-pairing mobile phase (i.e. octylsulfate as counter-ion), a reversed-phase column (LiChrospher 100 RP 18 end-capped), post-column derivatization with ortho-phthalaldehyde and 2-mercaptoethanol and fluorescence detection.
The authors report the results of molecular biology techniques for the early diagnosis of cases (... more The authors report the results of molecular biology techniques for the early diagnosis of cases (invasion phase) of schistosomiasis during two epidemics occurring during French military projects in the Central African Republic and Madagascar. The use of these techniques in real time for subjects not residing in the endemic area significantly improves the sensitivity of screening. The attack rates of these episodes, according to a case definition that took positive specific PCR results into account, were 59% and 26%. These results are a concrete illustration of the proverb that "yaws begin where the trail stops".
Abstract An HPLC method and a microbiological assay developed for measuring amoxicillin in calf p... more Abstract An HPLC method and a microbiological assay developed for measuring amoxicillin in calf plasma were used in pharmacokinetic studies of the β-lactam antibiotic following intramuscular administration of the test compound. Collected samples were concomitantly ...
Gold nanoparticles (AuNP) hold great potential for biomedical applications. This study was aimed ... more Gold nanoparticles (AuNP) hold great potential for biomedical applications. This study was aimed at examination of the effect of AuNP coating on the redox status of their environment. Two kinds of AuNP were tested, similar by shape and size, but with different surface coatings: either stabilized with citrate or functionalized with dihydrolipoic acid (Au@DHLA NP). Interestingly, whereas citrate-stabilized AuNP interact in vitro with reduced glutathione (GSH) and S-nitrosoglutathione, Au@DHLA NP do not interfere with both biomolecules. Albumin exhibits higher affinity toward citrate-stabilized AuNP than Au@DHLA NP, increasing their hydrodynamic diameter (8.0- and 1.3-fold, respectively). Furthermore, the AuNP coating affects also their internalization by macrophages (which was two fold higher for citrate-stabilized AuNP), following an exposure to a subtoxic NP concentration (10 nM, 80% viability). Citrate-stabilized AuNP were found to decrease the intracellular GSH level (ca. 20%), with no increase in reactive oxygen species production. Furthermore, these AuNP did not induce apoptosis (as shown by caspase-3 activity and nfkb2 transcription factor), and also did not activate gene expression related to oxidative stress (ncf1) and inflammatory response (tnfα). The present data highlight that the functionalization of AuNP with DHLA decreases their reactivity with biomolecules and cells, resulting in a promising medical platform.
... Agenda setting (Streck 2002b60. Streck, C. 2002b. Global public policy networks as coalition... more ... Agenda setting (Streck 2002b60. Streck, C. 2002b. Global public policy networks as coalitions for change. In ... View all references; Streck 2002b60. Streck, C. 2002b. Global public policy networks as coalitions for change. In ...
Abstract Menthol glucoronide was measured in the presence of borneol glucuronide as internal stan... more Abstract Menthol glucoronide was measured in the presence of borneol glucuronide as internal standard by a high-performance liquid chromatography method including a prec-column derivatization step. The carboxylic group of glucuronic acid conjugates was ...
We have studied the pharmacokinetics of tiopronin and its principal metabolite, 2-mercaptopropion... more We have studied the pharmacokinetics of tiopronin and its principal metabolite, 2-mercaptopropionic acid (2-MPA) in healthy volunteers after the oral administration of 500 mg (2 Acadione tablets), followed by simultaneous assay of the two compounds in plasma over a period of 48 h using a new method (emission of fluorescence after HPLC and post-column derivatization by pyrene-maleimide). The absorption of tiopronin was slow (tmax between 4 and 6 h) and the plasma concentrations subsequently fell biexponentially. The principal metabolite 2-MPA appeared later in the plasma (tmax between 10 and 12 h after a lag-time of 3 h) then disappeared monoexponentially. About 15% of the tiopronin was metabolized to 2-MPA.
A method for the assay of various forms of glutathione in human plasma has been developed. The re... more A method for the assay of various forms of glutathione in human plasma has been developed. The reduced form was measured after direct injection of deproteinized plasma with perchloric acid. The unbound oxidized forms were assayed in deproteinized plasma ...
A simple, fast, sensitive method for determination of amikacin in dog plasma using high-performan... more A simple, fast, sensitive method for determination of amikacin in dog plasma using high-performance liquid chomatography (HPLC) is described. A 10 % (w/v) trichloroacetic acid solution was used to deproteinate plasma. After centrifugation of the sample, a 100 μ.1 aliquot of supernatant was directly injected onto the chromatograph. HPLC conditions consisted of an ion-pairing mobile phase (i.e. octylsulfate as counter-ion), a reversed-phase column (LiChrospher 100 RP 18 end-capped), post-column derivatization with ortho-phthalaldehyde and 2-mercaptoethanol and fluorescence detection.
The authors report the results of molecular biology techniques for the early diagnosis of cases (... more The authors report the results of molecular biology techniques for the early diagnosis of cases (invasion phase) of schistosomiasis during two epidemics occurring during French military projects in the Central African Republic and Madagascar. The use of these techniques in real time for subjects not residing in the endemic area significantly improves the sensitivity of screening. The attack rates of these episodes, according to a case definition that took positive specific PCR results into account, were 59% and 26%. These results are a concrete illustration of the proverb that "yaws begin where the trail stops".
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Papers by P. Leroy