Biomedical subjects

C E Muller

Publications and source records attributed to C E Muller.

3 recordsLinked to original sources

PubMed2001

Kinetics and mechanisms of aqueous ozone reactions with bromide, sulfite, hydrogen sulfite, iodide, and nitrite ions.

Reactions of ozone with Br(-), SO(3)(2-), HSO(3)(-), I(-), and NO(2)(-), studied by stopped-flow and pulsed-accelerated-flow techniques, are first order in the concentration of O(3)(aq) and first order in the concentration of each anion. The rate constants increase by a factor of 5 x 10(6) as the nucleophilicities of the anions increase from Br(-) to SO(3)(2-). Ozone adducts with the nucleophiles are proposed as steady-state intermediates prior to oxygen atom transfer with release of O(2). Ab initio calculations show possible structures for the intermediates. The reaction between Br(-) and O(3) is accelerated by H(+) but exhibits a kinetic saturation effect as the acidity increases. The kinetics indicate formation of BrOOO(-) as a steady-state intermediate with an acid-assisted step to give BrOH and O(2). Temperature dependencies of the reactions of Br(-) and HSO(3)(-) with O(3) in acidic solutions are determined from 1 to 25 degrees C. These kinetics are important in studies of annual ozone depletion in the Arctic troposphere at polar sunrise.

Journal Article↗

PubMed2000

Adenosine receptor ligands-recent developments part I. Agonists.

Developments in the field of adenosine receptor (AR) agonists of the past years are presented and discussed. Four different AR subtypes, A(1), A(2A), A(2B), and A(3), have been cloned from different species including the human receptors. Recombinant ARs expressed in permanent mammalian cell lines have found wide application in the screening of new ligands. Considerable differences are observed among data from different laboratories, using recombinant receptors for the assays. Reevaluation of compounds at all four receptor subtypes has shown that agonists that were believed to be selective for either A(1) or A(2A) ARs may be potent A(3) agonists and thus, non-selective. Potent and selective agonists for two of the AR subtypes, A(1) and A(3), have been developed. Truly selective A(2A) AR agonists, however, are presently not available. Potent or selective A(2B) agonists are still lacking. Since the treatment with AR agonists may lead to fast desensitization of the receptors, partial agonists, and indirect AR agonists, such as adenosine kinase inhibitors, or allosteric enhancers of adenosine binding, are being developed as site- and event-specific agents.

Adenosine↗

PubMed1993

[Obtaining an adequate Pap cell test].

Routine use of the Papanicolaou (Pap) smear has led to a decrease in mortality from cervical carcinoma. The Papanicolaou test examines exfoliated cells to detect preinvasive lesions (eg, dysplasia, carcinoma-in-situ) as well as invasive lesions. Cervical screening is recommended for women who are sexually active regardless of age. For the woman who is not sexually active, cervical screening should begin at 18 years of age. An essential part of a good Pap smear technique is that the specimen should consist of cells from the squamocolumnar junction. It is important that the specimen should be fixed quickly.

Adolescent↗