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Biomedical subjects

R Pichon

Publications and source records attributed to R Pichon.

18 recordsLinked to original sources
PubMed2002

Analysis and quantification of prescribing and transcription errors in a paediatric oncology service.

OBJECTIVE: To analyse and quantify the omission errors linked to physicians' prescribing and errors linked to nurses' transcription and to identify the type and frequency of factors associated. No pharmacological factors are taken into account. DESIGN: Analysis of physicians' prescriptions and nurses' transcriptions in chemotherapeutic treatments (20 patient files) and non-chemotherapeutic treatments (20 patient files); retrospective study. SETTING: Paediatric onco-haematology unit. MAIN OUTCOME MEASURES: Categorisation of physicians' prescriptions as complete or incomplete, categorisation of the various nurses' transcriptions as correct or incorrect. RESULTS: Physicians' prescriptions were complete for 61.6% of non-chemotherapy treatments. As each prescription is transcribed twice, two nurses' transcription sheets are filled in by the nurses. At the first transcription 79.3% of non-chemotherapy prescriptions and 88.2% of chemotherapy prescriptions were transcribed correctly, while in the second sheet these percentages were respectively 96.2% and 93.7%. CONCLUSIONS: Too many sheets of paper generate confusion and increase the risk of errors. The several transcriptions are, in both types of treatment, sources of errors. The problems identified in this study allowed us to open a discussion as how to improve the physicians prescriptions and the nurses' transcription sheets.

Child↗
PubMed1999

Structure of the exopolysaccharide of Vibrio diabolicus isolated from a deep-sea hydrothermal vent.

The structure of the exopolysaccharide produced under laboratory conditions by Vibrio diabolicus, a bacterium recovered from a deep-sea hydrothermal vent, has been investigated using sugar and methylation analysis and NMR spectroscopy. The polysaccharide consists of a linear tetrasaccharide repeating unit with the following structure. -->3)-beta-D-Glcp Nac-(1-->4)-beta-D-Glcp A-(1-->4)-beta-D-Glcp A-(1-->4)-alpha-D-Galp NAc-(1-->

Amino Sugars↗
PubMed1999

Structural determination of the exopolysaccharide of Pseudoalteromonas strain HYD 721 isolated from a deep-sea hydrothermal vent.

The structure of the exopolysaccharide produced by Pseudoalteromonas reference strain HYD 721 recovered from a deep-sea hydrothermal vent has been investigated. By means of methylation and beta-elimination analysis, selective degradation of the uronic acids, partial depolymerization and NMR studies, the repeating unit of the polymer was deduced to be a branched octasaccharide with the structure shown. [formula: see text]

Carbohydrate Sequence↗
PubMed1999

A 31P nuclear magnetic resonance study of the hydrothermal vent tube worm Riftia pachyptila.

31P nuclear magnetic resonance (NMR) was used to study the major phosphorylated compounds visible in perchloric extracts of three body regions of the vestimentiferan worm Riftia pachyptila: winged vestimentum, trunk and segmented posterior opisthosome. Two phosphagens (PGs) were present in vestimentum and opisthosome. The major resonance corresponded to those of phosphoarginine and phosphotaurocyamine, which cannot be discriminated on 31P NMR spectra. We have identified four distinct phosphodiesters (PDEs) in these tissues: glycerophosphorylethanolamine (GPE), serine ethanolamine phosphodiester (SEP), glycero-phosphorylcholine (GPC) and threonine ethanolamine phosphodiester (TEP). Three phosphonates or derivates (PAs) were observed in the three body regions. The minor one was identified as 2-aminoethyl phosphonate (2-AEP). The phosphorus profile of the trunk was appreciably different: one additional resonance in the PDE region and only one phosphagen peak were observed.

Animals↗
PubMed1996

Hydroxylation of carbon atoms of the alkyl chain of symmetrical N-nitrosodialkylamines by rat liver microsomes.

Liver microsomal preparations from control and treated rats (cytochromes P450 1A, 2B, 3A and 2E1-induced) metabolized at variable metabolic rates three nitrosodialkylamines (N-nitroso-dipropyl, dibutyl and diamyl-amines) into aldehydes and hydroxy-nitrosamines. The longer the alkyl chain, the smaller was the metabolic rate of the alpha-hydroxylation of alkyl chain yielding aldehyde and the greater was the metabolic rate of the corresponding (omega-1)-hydroxyl metabolite formation. Thus, the (omega-1) hydroxylation of the alkyl chain was the major metabolic pathway of N-nitrosodiamylamine (NDAA) so far as it represented 22-fold the alpha-hydroxylation. The balance between beta to omega hydroxylation and alpha-hydroxylation depends upon the alkyl chain length and also on specific P450 isoform induction.

Animals↗
PubMed1995

Osmoregulation by trehalose synthesis in Salmonella manhattan after exposure to waste waters.

A 24 h period in waste waters improved the subsequent survival of Salmonella in oligotrophic sea water, at 20 degrees C, compared to a direct input control. The main osmoprotective compound accumulated, investigated by 1H-NMR spectroscopy (nuclear magnetic resonance), after 6 d in sea water was trehalose. Taking into account these observations, this paper put forward the following explanation concerning the survival mechanism: (1) stress in waste waters induces the endogenous synthesis of trehalose via the activation of the gene kat F; (2) when exposed to an osmotic stress, two degradative cytoplasmic enzymes are repressed and the bacteria accumulate trehalose which acts as an osmoprotectant. The succession of the two steps enables Salm. manhattan to immediately resist to the high salinity of oligotrophic seawater.

Adaptation, Physiological↗
PubMed1993

Detection of phosphodiester resonances in the perfused heart from vertebrate ectotherms with nuclear magnetic resonance.

In vivo 31P NMR has been used to characterize the phosphorylated compounds present in the heart from vertebrate ectotherms. The perfused hearts from all animals experimented showed prominent resonances between the inorganic phosphate and phosphocreatine peaks. The pattern of these compounds was found to be different in the heart of the different species. As shown by 31P and proton NMR of perchloric extracts, the chemical shift of some of the compounds was characteristic of glycerophosphorylcholine, glycerophosphorylinositol, phosphorylcholine, phosphorylserine, phosphorylethanolamine and phosphoenolpyruvate. The non-identified resonances were found to be phosphodiesters, as demonstrated by alkaline phosphatase hydrolysis. The physiological significance of these high levels of phosphodiesters in the heart from vertebrate ectotherms is discussed.

Alkaline Phosphatase↗
PubMedDate not supplied

Quantitation of pentobarbital in serum by enzyme immunoassay.

Pentobarbital was quantitated in serum by a homogeneous enzyme immunoassay (EMIT), and the method evaluated for accuracy and precision. A comparison was performed against the authors' modified Goldbaum ultraviolet spectrophotometric procedure. The analytical sensitivity was 2 micrograms/mL with a linearity to 10 micrograms/mL and a coefficient of variation of 6.24%. Linear regression analysis revealed a correlation coefficient of 0.977, a slope of 1.05, and an intercept of -0.07. The t test demonstrated no difference between the two methods at a level of P less than 0.01. The enzyme immunoassay also had the advantages of speed and small sample requirement.

Barbiturates↗