Polyacrylate adsorbents for the selective adsorption of cholesterol-rich lipoproteins from plasma or blood

Polyacrylate (PAA) adsorbents selectively bind low density lipoproteins (LDL) from human plasma and blood, whereas very low density lipoproteins (VLDL) are only minimally adsorbed. The adsorption of cholesterol-rich lipoproteins to PAA adsorbents is related to the molecular weight (mw) of the polyanion ligand. Ca++ and Mg++ inhibit the binding of LDL to PAA adsorbents. The chemical composition of the organic hardgels of the adsorbents does not have an influence on adsorption. The selective adsorption of LDL to PAA adsorbents can be explained to result from their low negative surface charge density and the specific colloid-chemical properties of the surface-bound PAA, which do not prevent LDL from binding to charge-like domains of the ligand. By contrast, VLDL and high density lipoproteins (HDL) are repelled from the adsorbents due to their higher negative surface charge density

Photochemische Cycloadditionen von 3-Phenyl-2 H

Similarly to aldehydes [6] ketones form 3-oxazolines via cycloaddition to the benzonitrile-methylides 2 that arise photochemically from the 3-phenyl-2H-azirines 1. With various ketones benzonitrile-isopropylide (2a) gives cycloaddition products in very good preparative yields (scheme 1). Benzonitrile-ethylide (2c) and benzonitrile-benzylide (2b) [8] react, however, sluggishly with ketones, smooth cycloaddition being observed in their case only with ‘activated’ ketones (2,2,2-trifluoroacetophenone, 1,1,1-trifluoro-2-propanone). With 1a acetonylacetone forms the bis-adduct 12. While the azirine 1a reacts with cyclohexanone to yield essentially only the spiro-(3-oxazoline) 13, it gives with cyclopentanone, depending on the reaction conditions, either the spiro-(3-oxazoline) 14 or the butenyl-3-oxazoline 15 (scheme 3). The formation of 15 has to be preceded by the photochemical formation of 4-pentenal from the ketone. Norcamphor and camphor react in a similar way (schemes 4 and 5). The azirines 1a–c react smoothly with the keto group in acylcyanides and alpha-keto-esters, giving with the former 5-cyano-3-oxazolines and with the latter 5-ethoxycarbonyl-3-oxazolines (schemes 6 and 7). Beta-keto-esters (acetoacetic ester) form with the dipole arising from 1a the expected addition product 31 and, via the protonated dipole d (scheme 8), finally the benzylidene-acetoacetic ester. Analogous results are obtained with malonodinitrile, trifluoroacetamide and other weak acids such as alcohols [29][30] (scheme 9). The light-induced rearrangement of the bicyclic isoxazoline 37 into the oxazoline 38 is visualized as an intramolecular cycloaddition reaction (scheme 10). The cycloaddition in this case proceeds with the aldehyde group inversed as compared to the related intermolecular benzonitrile-methylide addition to aldehydes

Bench Aids for the diagnosis of intestinal parasites

A set of nine A-4 colour plates with 118 photomicrographs illustrating the appearance and diagnostic features of all the common intestinal helminths and protozoan parasites known to infect humans. Produced in a robust plasticized format, the plates can be used as either a guide for laboratory and field workers in endemic countries or a teaching aid for students and trainees. The aim is to help the microscopist ascertain the presence of parasites in faeces, whether they be minute protozoan cysts or large helminth eggs, and to identify them correctly. With this goal in mind, the bench aids include pertinent laboratory instructions as well as high-quality images. The photomicrographs illustrate diagnostic features of each of the parasites as they appear in different preparations and at different magnifications. Each photomicrograph is produced with a measuring bar and accompanied by a short explanatory legend, which draws attention to distinctive features that help confirm diagnosis. Helminth eggs are illustrated in the first 36 photomicrographs, which show the diagnostic stages of the most common helminths, including nematodes, cestodes, schistosomes, and other trematodes. The remaining photomicrographs offer advice on the more difficult task of detecting and identifying intestinal protozoan trophozoites and cysts. Relevant laboratory techniques are described on the reverse side of the plates. Additional laboratory aids include dichotomous keys for the identification of amoebic trophozoites, trophozoites of intestinal flagellates, and cysts of amoebae and flagellate