PubMed Health⌕ Search

Biomedical subjects

C Bonnefoy

Publications and source records attributed to C Bonnefoy.

7 recordsLinked to original sources
PubMed2006

[Inductively coupled plasma mass spectrometry. Perspectives in analysis and in biology].

ICP-MS is an instrumental method of multi-elementary qualitative and quantitative analysis. It associates with a mass spectrometer (MS) an ion source composed of a plasma torch fed with inductive coupling with a high frequency electromagnetic generator (ICP), similar to that used as a light source in highly-successful Atomics Emission Spectrometry (AES). ICP-MS can be applied to simultaneous analysis of numerous metallic and metalloid elements (80 or so). Its sensitiveness is all in all far better than that available with previous spectrometric techniques, which nevertheless remain more advantageous for processing certain low atomic mass elements. Thanks to its broad dynamic range, ICP-MS allows quantification of an array of elementary concentrations within a single sample. ICP-MS offers particularly interesting perspectives in geochemistry and metal processing, as well as in biochemistry and food or toxicology and environmental analysis. Implementation is rapid and the technique is suitable for series or continuous analyses, or for analysis of any evolving medium such as effluents from gas or liquid chromatography or from capillary electrophoresis, making it a valuable tool for speciation analyses. Finally it enables non-radioactive isotopic labeling, essential for nutritional studies of trace elements, and sufficiently accurate isotopic dilutions, even with more accessible machines.

Animals↗
PubMed2005

Determination of chromium in whole blood by DRC-ICP-MS: spectral and non-spectral interferences.

Quantification of chromium in whole blood has been performed by ICP-quadrupole MS. The spectrometer was equipped with a dynamic reaction cell (DRC) with ammonia as reaction gas. The rejection parameter q (RPq) of the DRC and the flow rate of ammonia (NH3) were optimized and set at 0.7 and 0.6 mL min(-1), respectively. Blood was diluted 1:51 (v/v) with an aqueous solution containing 0.1 mg L(-1) NH4OH, 0.1 g L(-1) EDTA, 5 mg L(-1) n-butanol, and 0.1 per thousand Triton X100. Non-spectral matrix effects observed when using the DRC were confirmed by use of vanadium. External calibration with blank and standard solutions prepared in purified water led to biased results for quality control samples. Standard addition calibration was therefore used and its validity verified. By comparing the slopes and calculating residues, it was proved that the plot obtained with standard additions and the plot obtained from blood samples of different concentrations were aligned down to 0.05 microg L(-1) after dilution.

1-Butanol↗
PubMed1995

Cell surface localization of proteolysis of human endothelial angiotensin I-converting enzyme. Effect of the amino-terminal domain in the solubilization process.

Angiotensin-converting enzyme (ACE) belongs to the type I class of ectoproteins and is solubilized by Chinese hamster ovary cells transfected with the full-length human ACE cDNA. ACE release in Chinese hamster ovary cells involves a proteolytic cleavage occurring in the carboxyl-terminal region, between Arg-1137 and Leu-1138. The subcellular localization of ACE proteolysis was established by pulse-chase experiments, cell surface immunolabeling, and biotinylation of radiolabeled mature proteins. The proteolysis of ACE takes place primarily at the plasma membrane. The solubilization of ACE is less than 2% within 1 h, is increased 2.4-fold by phorbol esters, but is not influenced by ionophores. An ACE mutant lacking the transmembrane domain and the cytosolic part (ACE delta COOH), is secreted at a faster rate without a carboxyl-terminal cleavage, and phorbol esters or ionophores have no effect on its rate of production in the medium. Therefore, the proteolysis of ACE is dependent on the presence of the membrane anchor and suggests that the secretase(s) involved is also membrane-associated. An ACE mutant lacking the amino-terminal domain (ACECF) is secreted 10-fold faster compared with wild-type ACE. The solubilization of ACECF occurs at the plasma membrane and is stimulated 2.7-fold by phorbol esters, and the cleavage site is localized between Arg-1227 and Val-1228. The amino-terminal domain of ACE slows down the proteolysis and seems to act as a "conformational inhibitor" of the proteolytic process, possibly via interactions with the "stalk" of ACE and the secretase(s) itself.

Amino Acid Sequence↗