Function of surface membrane structures in Thiobacillus thiooxidans

The function of the surface membrane structures was studied with cytochemical techniques on ultrathin sections of Thiobacillus thiooxidans. The transport of elementary sulphur inside the cell involves the surface membrane structures, while oxidation of the sulphur to sulphuric acid takes place on the outer surface of the cytoplasmic membrane. The surface membrane structures are supposed also to participate in the primary dissolution of elementary sulphur at the site of contact of the cells with the mineral.     

Short-term effects of norethisterone oenanthate and medroxyprogesterone acetate on glucose, insulin, growth hormone, and lipids

The synthesis of (+/-)-1-ethylenedioxy-trans-2-(beta-R,S-hydroxypropyl)-3-(beta-acetoxyethyl)cyclopentane (IV), starting from (+/-)-1-ethylenedioxy-trans-2-propargyl-3-(beta-hydroxyethyl)cyclopentane (I) by indirect hydration with mercuric acetate and hydrogen sulphide, is reported.     

Pellegrini-Stieda disease (shadow)]

Inadvertent use of tetracycline hydrochloride while producing calcium oxalate stones in the rat resulted in a reduction of papillary concretions by one-half. Parenchymal calcifications in the continuing long term, preformed stone group were reduced to levels comparable to that of other useful agents. In vitro studies corroborated these findings at physiologic urinary pH ranges. The rationale and comparisons to other anticalculus drugs are discussed.     

Effects of dextran on the molecular structure and tensile behaviour of human fibrin

Characteristic changes induced by dextran during the conversion of fibrinogen to fibrin have previously been shown to be associated with profound alterations in morphology of fibrin. However, whether dextran is incorporated into the fibrin molecule and whether morphological changes are associated with alterations in mechanical behaviour of formed fibrin was unclear. The investigations described show that the fibrin made in the presence of dextran has a shortened syneresis time, a lowered modulus of elasticity, an increased elongation and diminished ultimate strength at break. The molecular composition of fibrin clots remains unaltered despite the altered mechanical properties and morphological changes. Furthermore, dextran is not incorporated into the fibrin structure in any appreciable quantity. It is suggested that these several effects of dextran on clot morphology, tensile behaviour and kinetics of fibrin formation arise from increased forces of attraction between fibrin molecules such that fibrin chains are held together by weak secondary cross-links rather than by stronger primary cross-links which are hidden within the thicker fibrin chain bundles.