Polychloroformiate de vinyle: Support inerte de principes actifs,fixation et hydrolyse in vitro de sympathomimétiques

The chemical modification of poly(vinyl chloroformate) with sympathomimetics (phenyl ethylamine, ephedrine, p-hydroxyephedrine and p-hydroxymorephedrine) has been investigated. We have found convenient conditions to obtain soluble modified polymers with nearly quantitative substitution. The use of labelled compounds has shown that the rate and the yield of fixation on the polymer are independent of the nature of the amine. Kinetics in vitro of cleavage has shown that the rates of hydrolysis in stomacal, intestinal and enzymatic media are very low and similar; the observed variations seem to result from differences in solubility of the various modified polymers.     

Polytypisme dans le systeme titane-soufre

Polytypism has been observed among non stoichiometric compounds. in the titanium-sulphur system. This phenomenon, studied at 800 and 900°C, appears near the composition TiS_1,70. Among a lot of varieties which commonly exhibit one-dimensional disorder, four structures have been worked out (12H, 48R, 8H, 10H) and four others identified (12H_a, 24H_b, 40H, 696R).A method is given for accurate evaluation of composition and z coordinates of sulphur atoms. Thus it appears that in these polytypes, atomic planes are equally spaced. Several modes of coexistence of two types present in a single crystal have been studied.     

45- and 70-base DNA supramolecular polymerizations on quartz crystal microbalance biosensor

Supramolecular polymerizations of 45- and 70- base DNAs on the surface of an in-situ time-resolved 27 MHz quartz crystal microbalance biosensor.     

Ultra-trace analysis of platinum in human tissue samples

Background levels of platinum were determined in human autopsy tissues taken from five individuals. The investigated specimens were lung, liver and kidney. Sample preparation involved microwave digestion followed by an open vessel treatment. Inductively-coupled plasma sector field mass spectrometry (ICP-SFMS) was applied in combination with an ultrasonic nebulization/membrane desolvation system for sample introduction. Isotope dilution analysis was employed for accurate quantification of platinum. Excellent procedural detection limits (3 s validation) of 20, 20 and 34 pg g^–1 dry weight were obtained for lung, liver and kidney tissue, respectively. Due to the lack of appropriate biological reference material, road dust (BCR-723) was used for method validation. Platinum levels ranging between 0.03 and 1.42 ng g^–1 were determined in the investigated samples. The platinum concentrations observed in human lung tissue may reflect the increasing atmospheric background levels of platinum originating from car catalysts. The presence of platinum in kidney and liver tissue samples clearly indicates the bioavailability of the element.     

Zur Kenntnis der Reaktion zwischen Pyrrolidon und Aldehyden

Ohne Zusammenfassung     

Synthesis of Alkenyl-Substituted Allenecarboxylates

The Wittig olefination of decanoyl chloride by using the phosphonium salt 1 in the presence of two equivalents of Et₃N represents a one-step synthesis of the racemic form of the naturally occurring pheromone (–)- 2 which contains an alkenyl-substituted allenic moiety (ef. Scheme 1). It is also shown, that unsaturated acyl chlorides which contain at least one γ-H-atom undergo the Wittig reaction with an appropriate phosphorane yielding γ-alkenyl-substituted α-allenic esters and α-allenic γ-lactones, respectively (ef. Schemes 2 and 3).     

Interaction of the mu-opioid receptor with GPR177 (Wntless) inhibits Wnt secretion: potential implications for opioid dependence

Background  

Opioid agonist drugs produce analgesia. However, long-term exposure to opioid agonists may lead to opioid dependence. The analgesic and addictive properties of opioid agonist drugs are mediated primarily via the mu-opioid receptor (MOR). Opioid agonists appear to alter neuronal morphology in key brain regions implicated in the development of opioid dependence. However, the precise role of the MOR in the development of these neuronal alterations remains elusive. We hypothesize that identifying and characterizing novel MOR interacting proteins (MORIPs) may help to elucidate the underlying mechanisms involved in the development of opioid dependence.