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Biomedical subjects

A Z Britten

Publications and source records attributed to A Z Britten.

12 recordsLinked to original sources
PubMed1983

Disruptive effects of tris and sodium lauroyl sarcosinate on the outer membrane of Pseudomonas cepacia shown by fluorescent probes.

The disruptive effects of Tris buffer and sodium lauroyl sarcosinate (Sarkosyl) on the outer membrane (OM) of Pseudomonas cepacia were investigated with several fluorescent probes. Tris increased the permeability of the OM to 6-anilino-l-naphthalenesulphonic acid and 2-p-toluidinylnaphthalene-6-sulphonate. The degree of damage to the OM was enhanced when the pH was decreased 3-(N-morpholino)propanesulphonic acid buffer had a small but significant effect at acid pH, while citrate/phosphate buffer showed insignificant effects. Sarkosyl released 3,3'-dipentyloxacarbocyanine iodide (CC5) from CC5-labelled OM or whole cells and altered OM fluidity as studied by fluorescence polarization.

Anilino Naphthalenesulfonates↗
PubMed1976

A new rapid assay of oestrogens in pregnancy urine using the substrate native fluorescence.

A simple and rapid method is described for the quantitative determinations of free and conjugated oestrogens in pregnancy urine. The oestrogens are precipitated with ammonium sulphate and freed from non-oestrogenic compounds by solvent extraction. The conjugated oestrogens are hydrolysed by a beta-glucuronidase from Escherichia coli, and the total free oestrogens are extracted into ether and their fluorescence intensity at 310 nm in this solvent is determined. The method is rapid and precise for oestrogen levels at concentrations greater than 2 mug/ml (7 mumol/1). It is proposed that this method, which measures oestradiol and oestriol levels, be applied routinely to monitor feto-placental function in pregnancy. It offers advantages over other currently used assays in that less manipulative and technical skill is required to give a high level of precision and accuracy. An accurate estimate can be produced within 30-60 min of receipt of a 24-h uring specimen. Two variations of the method are also described. In one the ammonium sulphate precipitation step is omitted so as to give an even quicker assay procedure which determines conjugated oestrogens in the urine, and in the other oestriol only is determined.

Estrogens↗
PubMed1975

Evaluation of coal tar fractions for use in psoriasiform diseases using the mouse tail test. (I) High and low temperature tars and their constituents.

'High' and 'low' temperature tars were evaluated on parakeratotic mouse tail skin, which was used as a model for the psoriatic keratinization process. The skin was examined histologically for signs of induced granular layers in previously scaly areas; epidermal thicknesses were also measured. It appears that the acidic (phenolic) fractions of coal tars induce granular layers and cause epidermal thickening, whereas neutral constituents alone only cause thickening. It is suggested that tar acids should be further investigated for anti-psoriatic activity.

Animals↗
PubMed1975

Evaluation of coal tar fractions for use in psoriasiform diseases using the mouse tail test. III. High boiling tar oil acids.

Twelve phenolic fractions of creosote and anthracene oils derived from a high temperature tar were applied in an ointment base to mouse tail skin. After treatment with the higher boiling acids, formerly parakeratotic scale areas underwent granular layer induction and 'basket-weave' keratin was produced. Changes in distribution of acid phosphatase and in horny layer fluorescence were consistent with the conversion to an orthokeratotic state. It is suggested that some of these phenols may be of value in the treatment of chronic psoriasis.

Acid Phosphatase↗