Elongation of (omega-14C)oleic acid and (omega-14C)nervonic acid

During feeding experiments with [omega-14C]oleic acid and [omega-14c]nervonic acid to adult rats, 14C-labelled C26, C28 and C30 fatty acids were recovered from the intestinal mucosa, liver, plasma, kidney and stools. The structures of these fatty acids were determined by g.l.c., radio-g.l.c. and mass spectrometry. The Schmidt and Ginger degradation methods indicated that most of the 14C found in these extra-long fatty acids remained in the omega position. These radioactive extra-long fatty acids were found mainly in the polar lipids of rats killed 3 or 15 h after being fed on labelled oleic acid or nervonic acid. Rats killed 63 h later yielded only traces of these extra-long fatty acids. When the rats were given antibiotics or received the same radioactive fatty acids by intravenous injection, the labelled extra-long fatty acids could not be detected in any of the tissues. We conclude that they were probably synthesized by elongation of oleic acid and nervonic acid by intestinal micro-organisms (probably yeasts) and then absorbed by the intestinal mucosa.     

Residue-specific immobilization of protein molecules by size-selected clusters

The atomic force microscope (AFM), operating in contact mode, has been employed in buffer solution to study two proteins; (i) green fluorescent protein (GFP), from the hydromedusan jellyfish Aequorea victoria; and (ii) human oncostatin M (OSM), in the presence of size-selected gold nanoclusters pinned on to a highly oriented pyrolytic graphite substrate. The AFM images have revealed immobilization of single molecules of OSM, which are strongly bound to the gold nanoclusters. Conversely, no strong immobilization has been observed for the GFP, as these molecules were easily displaced by the scanning tip. The contrasting behaviour of the two proteins can be explained by the exposed molecular surface area of their cysteine residues as modelled on the basis of their respective X-ray crystallographic data structures. GFP contains two cysteine residues, but neither is readily available to chemisorb on the gold clusters, because the cysteines are largely inaccessible from the surface of the protein. In contrast, OSM has a total of five cysteine residues, with different degrees of accessibility, which make the protein amenable to anchoring on the nanoclusters. Statistical analysis of the height of the OSM molecules bound to the nanoclusters is in accordance with crystallographic data, and suggests various configurations of the proteins on the clusters, associated with the presence of different cysteine anchoring sites. These results suggest that the three-dimensional conformation of protein molecules is preserved when they are chemisorbed to size-selected gold clusters, thus opening a new route towards oriented immobilization of individual protein molecules.     

Evidence of deuterium re-trapping by boron after electron beam dissociation of B–D pairs in diamond

In order to clarify the mechanism responsible for the dissociation of B–D complexes in diamond, electron-beam exposure of deuterated boron-doped diamond was carried out and followed in situ at low temperatures (10–100 K). We show that, in addition to the dissociation process, a re-trapping phenomenon of deuterium by boron is observed at T < 90 K. The nature of this re-trapping is investigated and an experimental protocol to evaluate the exact dissociation rate of B–D complexes under e-beam at low temperatures is discussed.     

Public health education integrated in hospital. An internship proposal, "Medical information and pharmacology"

1. Human cytochrome P450 (CYP) isoenzymes expressed in a human cell line were used to elucidate their involvement in the metabolism of haloperidol (HAL). 2. It was found that CYP3A4 catalyzes the metabolism of HAL to HAL 1,2,3,6-tetrahydropyridine (HTP). HTP is further metabolized to HAL pyridinium (HP+) by both CYP3A4 and CYP2D6. 3. CYP3A4 and CYP2D6 are also responsible for the N-dealkylation of HAL. The N-dealkylation of reduced HAL (RH) was observed, which is catalyzed by CYP3A4. In addition, CYP3A4 also catalyzes the oxidation of RH back to HAL. 4. These results are discussed in terms of the metabolic interactions of HAL with other drugs and how this knowledge may be used to reduce the movement disorders induced by HAL.     

Effect of ion implantation on thin hard coatings

The surface mechanical properties of thin hard coatings of carbides, nitrides and borides deposited by r.f. sputtering were improved after deposition by ion implantation. The thickness and the stoichiometry of the films were measured by Rutherford backscattering spectrometry and nuclear reaction analysis before and after ion bombardment. The post ion bombardment was achieved with heavy inert ions such as Kr⁺ and Xe⁺ with an energy sufficient to penetrate the film and to reach the substrate. Both the film adhesion and the microhardness were consistently improved. In order to achieve a more detailed understanding, Rb⁺ and Ni⁺ ions were also used as projectiles, and it was found that these ions were more effective than the inert gas ions.     

Histiocytoid cardiomyopathy: a cause of sudden death in infancy

We report the case of an infant aged of 14 months deceased of sudden death. The diagnosis of histiocytoid cardiomyopathy was made on a necropsic basis. The pathologic examination showed a cardiac hypertrophy characterized by yellowish areas with irregular outlines, disseminated in the myocardium, and made of histiocyte-like cells with foamy or granular cytoplasm. These cells reacted positively with desmin and myoglobin labels, and had rare and disorganised myofibrils in electron microscopy, proving their muscular origin. The illness affects infants and usually causes severe cardiac troubles leading to death without treatment. This case is the fourteenth associated with sudden death.     

Comparison of sample preparation methods,validation of an UPLC–MS/MS procedure for the quantification of tetrodotoxin present in marine gastropods and analysis of pufferfish

Tetrodotoxin (TTX) is one of the most potent marine neurotoxins reported. The global distribution of this toxin is spreading with the European Atlantic coastline now being affected. Climate change and increasing pollution have been suggested as underlying causes for this. In the present study, two different sample preparation techniques were used to extract TTX from Trumpet shells and pufferfish samples. Both extraction procedures (accelerated solvent extraction (ASE) and a simple solvent extraction) were shown to provide good recoveries (80–92%). A UPLC–MS/MS method was developed for the analysis of TTX and validated following the guidelines contained in the Commission Decision 2002/657/EC for chemical contaminant analysis. The performance of this procedure was demonstrated to be fit for purpose. This study is the first report on the use of ASE as a mean for TTX extraction, the use of UPLC–MS/MS for TTX analysis, and the validation of this method for TTX in gastropods.     

Diaphyseal fractures treated by polylactide and hydroxyapatite pins. Experimental study in rat

Hydroxyapatite (HAp) coatings were deposited onto substrates of metal biomaterials (Ti, Ti6Al4V, and 316L stainless steel) by electrophoretic deposition (EPD). Only ultra-high surface area HAp powder, prepared by the metathesis method 10Ca(NO₃)₂ + 6(NH₄)₂HPO₄ + 8NH₄OH), could produce dense coatings when sintered at 875–1000°C. Single EPD coatings cracked during sintering owing to the 15–18% sintering shrinkage, but the HAp did not decompose. The use of dual coatings (coat, sinter, coat, sinter) resolved the cracking problem. Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) inspection revealed that the second coating filled in the valleys in the cracks of the first coating. The interfacial shear strength of the dual coatings was found, by ASTM F1044-87, to be 12 MPa on a titanium substrate and 22 MPa on 316L stainless steel, comparing quite favorably with the 34 MPa benchmark (the shear strength of bovine cortical bone was found to be 34 MPa). Stainless steel gave the better result since -316L (20.5 m mK^-1) > -HAp (14 m mK^-1), resulting in residual compressive stresses in the coating, whereas -titanium (10.3 m mK^-1) < -HAp, resulting in residual tensile stresses in the coating. © 1999 Kluwer Academic Publishers     

Ammonia volatilization following surface application of raw and treated liquid swine manure

The treatment of liquid swine manure (LSM) is primarily intended to produce energy and/or decrease P concentration in the liquid fraction, but may have a simultaneous impact on its potential for N volatilization. We compared NH₃ volatilization in the field following surface application (May 2004; May 2005; September 2005) of untreated LSM and the liquid fraction of LSM (hereafter called treated LSM) that had undergone either natural decantation, filtration, anaerobic digestion, or anaerobic digestion + flocculation. Though most treatments increased pH and the proportion of total ammoniacal N (TAN) in LSM, the proportion of applied TAN lost as NH₃ was 22% lower with treated than untreated LSMs. Most likely, the increased infiltration rate of treated LSMs, associated with reduction in dry matter, compensated for increases in TAN and pH. Emissions of NH₃ on the day of application were correlated with LSM pH (R ² = 0.51) and were the highest with the digested and the digested + flocculated LSMs. However, these LSMs generally emitted less NH₃ than the other LSMs on the following days. As a consequence, when the volatilization period was short (e.g., dry soil conditions), the proportion of applied N lost from the digested and the digested + flocculated LSMs was similar or higher than the filtered and decanted LSMs. In contrast, when the volatilization period was long, the digested and digested + flocculated LSMs emitted less NH₃ than the other treated LSMs. It can be concluded that LSM treatments tended to decrease NH₃ volatilization, compared to the untreated LSM; across application dates, the digested LSM most consistently reduced NH₃-N losses whereas the filtered LSM was the least efficient.