Acylation of endogenous myelin proteolipid protein with different acyl-CoAs

Fatty acyltransferase activity that catalyzes the transfer of palmitic acid from palmitoyl-CoA to the endogenous myelin proteolipid protein has been demonstrated in isolated rat brain myelin. Optimum enzyme activity for the acylation of proteolipid protein was obtained in 0.1% Triton X-100, 2 mM MgCl2, and 1 mM dithiothreitol at a pH of 7.5 and at 37 degrees C. Other detergents had little or no effect on the reaction whereas acylation was completely abolished by sodium dodecyl sulphate (0.1%). Pulse-chase experiments indicated that the reaction involves the net addition of fatty acid to the protein and not a rapid fatty acid exchange. The rate of acylation was linear up to 30 min, indicating that the concentration of endogenous protein acceptor was constant. Under these conditions and at short time periods, the enzyme activity versus acyl-CoA concentration showed a hyperbolic curve. The apparent Km and Vmax for palmitoyl-CoA was 41 microM and 115 pmol/mg protein/min. Similar values were obtained for stearoyl and oleoyl-CoA, whereas myristoyl-CoA showed a lower specificity for the enzyme. The acyl-CoA specificity was also studied in competition experiments using several saturated and unsaturated fatty acid-CoAs. The product of the reaction was identified as myelin proteolipid protein and the fatty acid was shown to be attached to the protein via an ester linkage. Limited proteolysis and peptide mapping showed that the same sites on the proteolipid protein were acylated when the reaction was carried out in isolated myelin preparations or in brain tissue slices, suggesting physiological importance for the in vitro acylation of endogenous myelin proteolipid protein.     

Synthesis and structure-activity relationship of 2-(aminoalkyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives: a novel series of 5-HT(2A/2C) receptor antagonists. Part 2.

Following the programme started at Janssen Research Foundation searching for 5-HT(2A/2C) antagonists, we now report on the synthesis of a series of substituted 2-(Dimethylaminomethyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives. The 5-HT(2A), 5-HT(2C) and H(1) receptor affinities as well as the mCPP antagonistic activity of the compounds synthesised is described.     

Le vécu de l’AMP vu par l’homme: le point de vue du Psychologue

The medical management of infertile men has improved over the last twenty years: the man’s experience has been transformed from “castration” by his wife’s gynaecologist to technical management by ICSI, allowing the andrologist to deal with the patient’s global human complexity. Although failure is still a difficult experience, success raises the question of a modification of the man’s relationship to his child, resulting from this new method of procreation.     

The cationic polymerization of 3-O-acetyl-β-arabinofuranose 1,2,5-orthobenzoate

Cationic polymerisation of 3-O-acetyl-β-L-arabinofuranose 1,2,5-orthobenzoate initiated by either triphenylcarbonium tetrafluoroborate or benzoylium perchlorate has been studied. The existence of living chains was demonstrated by termination of polymerisation with tritium-labelled 1-butanol. The number of growing chains reached a maximum after ≈10 min and then decreased.     

Suction lipoplasty: biohazardous aerosols and exhaust mist--the clouded issue

With the increased popularity of suction lipoplasty procedures, attention has been focused on their safety. One significant concern involves the rotary vane aspirators used to provide the suction required for the procedure. A series of experiments was carried out to determine whether aerosols are produced during the use of a rotary vane aspirator, since aerosols are known to be hazardous under appropriate conditions. Using a viable strain of Pseudomonas aeruginosa, we challenged the system through the suction port, and the exhaust from the aspirator was then cultured in a particle sampler. Results indicate that viable pathogens are released from the exhaust in physiologically significant particles capable of penetrating to the level of the alveolus in the normal human lung. These infectious particles were produced for 3 hours after the initial challenge. When an appropriate filtration device was attached to the aspirator outflow, the aspirator pump and environment were protected. In the absence of an appropriate filtration device, the aerosolized particles may constitute a hazard to patients or medical workers in the vicinity of the aspirator.     

Propagation of Geotrichum candidum in Acid Brine

Geotrichum candidum completely neutralized the acid brine and reduced its biochemical oxygen demand (BOD) by 88%. Yield of dry mycelium was 62 g per 100 g of BOD utilized.     

The integument of the paddlefish,Polyodon spathula

The integument of the paddlefish (Polyodon spathula) is unusual as a relatively small amount of mucus is produced by epithelial cells that are not modified into regular mucous gland cells. A thick compact epidermis and dermis compensate for the slight amount of mucus secreted. Paddlefish have a variety of scales formed of concentric bony lamellae containing osteocytes. There are five kinds of scales: dorsal and ventral fulcra on the caudal fin, rhomboidal scales on the caudal lobe, horny denticles over the pectoral girdle, calcareous denticles on the trunk, and anchor-shaped plates on the rostrum. Except for the fulcra, the scales are undoubtedly vestigial. The numerous surface pits on the rostrum, head, operculum, and throat are epithelial invaginations which are not connected to lateral line canals. No nerves lead to the pits. The spherical to cuboidal and often ciliated cells at the base of the pits are considered to be aplasic cells of unformed neuromasts.