Heavy metal impregnation of specimens for electron microscopy offers a means for differential "staining" of various tissue components and cellular constituents. Of many silver impregnation methods, one of the most useful is Gomori's silver methenamine (1) after periodic acid oxidation (PA-SM) (2, 3). Several authors have applied silver impregnation to electron microscopy (4-7), mainly for the d...

An NADand GSH-dependent formaldehyde dehydrogenase (formaldehyde: NAD* oxidoreductase, EC 1.2.I.Z) was purified from rat and human liver, and the properties of these enzymes were compared. The GSH requirement of the enzyme obtained from both species could not be replaced by dithiothreitol, CoA or cysteine, and NADP could not substitute for NAD. The pH optimum, and the Km of formaldehyde and NAD...

PURPOSE The purpose of this study was to determine the presence of formocresol in the plasma of children undergoing oral rehabilitation involving pulp therapy under general anesthesia. METHODS Thirty 2- to 6-year-old preschool children were enrolled in the study. Preoperative, intra-operative, and postoperative peripheral venous samples were collected from each child. All samples were analyze...

We describe a procedure for the selection of alcohol dehyrogenase negative mutants in Drosophila. The method consists of exposing eggs and larvae to low concentrations of 1-pentyne-3-ol dissolved in the culture medium. Only those flies with greatly reduced levels of alcohol dehydrogenase activity survive. In addition, genotypically negative flies die if their mothers are alcohol dehydrogenase p...

The possibility of using the cation-exchange resin Lewatit K2420 as a catalyst for synthesis 1,3-butadiene from isopropyl alcohol and formaldehyde solution in one technological stage has been shown. regularities process have established influence form (a cyclic trimer 1,3,5-trioxane 37% water) on composition reaction mass yield main by-products assessed. It shown that heterogeneous showed catal...

Methyl formate synthase, which catalyzes methyl formate formation during the growth of methylotrophic yeasts, was purified to homogeneity from methanol-grown Candida boidinii and Pichia methanolica cells. Both purified enzymes were tetrameric, with identical subunits with molecular masses of 42 to 45 kDa, containing two atoms of zinc per subunit. The enzymes catalyze NAD(+)-linked dehydrogenati...

BACKGROUND Chlorhexidine is well known for its antiplaque effect. However, the mouthrinse based chlorhexidine antiplaque efficiency may vary according to the formulation of the final product. The aim of the present study was to compare anti-plaque effectiveness of two commercial mouthrinses: 0.12 % Chlorhexidine alcohol base (CLX-A) versus a diluted 0.1% Chlorhexidine non-alcohol base with 0.1%...

BACKGROUND Formaldehyde (HCHO) is a gas (available as a 37% concentrated solution, stabilized with methanol). The 10% dilution (approximately 4% formaldehyde) has been used as a fixative since the end of the 19th century. Alternative fixatives are also commercially available or may be prepared in-house in laboratories. Statements by the IARC, along with other USA agencies (CalEPA, RoC/NTP) on t...

An 8.6 kDa protein, which the authors call a modifin, has been purified from Methylococcus capsulatus (Bath) and has been shown to alter the substrate specificity and kinetics of NAD+-linked formaldehyde dehydrogenase (FDH) isolated from the same organism. Purification methods for both the modifin and FDH are presented which reliably produced pure protein for further analysis. Analysis of the m...

Dissolution of azo dyes derived from N-carboxylic acid-1,8-naphthalimide was studied in aqueous solutions containing formaldehyde condensation of naphthalenesulphonic acid and fatty alcohol ethylene oxide compound surfactants and effect of additional hydroxyl group on chemical structure of dye on dissolution was investigated. In addition, the effect of important factors on dissolution of used d...