Biomedical subjects

Ken Rose

Publications and source records attributed to Ken Rose.

4 recordsLinked to original sources

PubMed2002

Dehydroepiandrosterone (DHEA) metabolism in Saccharomyces cerevisiae expressing mammalian steroid hydroxylase CYP7B: Ayr1p and Fox2p display 17beta-hydroxysteroid dehydrogenase activity.

We have engineered recombinant yeast to perform stereospecific hydroxylation of dehydroepiandrosterone (DHEA). This mammalian pro-hormone promotes brain and immune function; hydroxylation at the 7alpha position by P450 CYP7B is the major pathway of metabolic activation. We have sought to activate DHEA via yeast expression of rat CYP7B enzyme. Saccharomyces cerevisiae was found to metabolize DHEA by 3beta-acetylation; this was abolished by mutation at atf2. DHEA was also toxic, blocking tryptophan (trp) uptake: prototrophic strains were DHEA-resistant. In TRP(+) atf2 strains DHEA was then converted to androstene-3beta,17beta-diol (A/enediol) by an endogenous 17beta-hydroxysteroid dehydrogenase (17betaHSD). Seven yeast polypeptides similar to human 17betaHSDs were identified: when expressed in yeast, only AYR1 (1-acyl dihydroxyacetone phosphate reductase) increased A/enediol accumulation, while the hydroxyacyl-CoA dehydrogenase Fox2p, highly homologous to human 17betaHSD4, oxidized A/enediol to DHEA. The presence of endogenous yeast enzymes metabolizing steroids may relate to fungal pathogenesis. Disruption of AYR1 eliminated reductive 17betaHSD activity, and expression of CYP7B on the combination background (atf2, ayr1, TRP(+)) permitted efficient (>98%) bioconversion of DHEA to 7alpha-hydroxyDHEA, a product of potential medical utility.

17-Hydroxysteroid Dehydrogenases↗

PubMed2002

Standards for Reporting Interventions in Controlled Trials of Acupuncture: the STRICTA recommendations.

Acupuncture treatment and control group interventions in parallel-group randomized trials of acupuncture are not always precisely reported. In an attempt to improve standards, an international group of experienced acupuncturists and researchers devised a set of recommendations, designating them STRICTA: STandards for Reporting Interventions in Controlled Trials of Acupuncture. In a further consensus-building round, the editors of several journals helped redraft the recommendations. These follow the Consolidated Standards for Reporting Trials (CONSORT) format, acting as an extension of the CONSORT guidelines for the specific requirements of acupuncture studies. Participating journals are publishing the STRICTA recommendations and requesting prospective authors to adhere to them when preparing reports for publication. Other journals are invited to adopt these recommendations. The intended outcome is that interventions in controlled trials of acupuncture will be more adequately reported, thereby facilitating an improvement in critical appraisal, analysis and replication of trials.

Acupuncture Therapy↗

PubMed2002

Standards for reporting interventions in controlled trials of acupuncture: The STRICTA recommendations. STandards for Reporting Interventions in Controlled Trails of Acupuncture.

Acupuncture treatment and control group interventions in parallel-group randomised trials of acupuncture are not always precisely reported. In an attempt to improve standards, an international group of experienced acupuncturists and researchers devised a set of recommendations, designating them STRICTA: STandards for Reporting Interventions in Controlled Trials of Acupuncture. In a further consensus-building round, the editors of several journals helped redraft the recommendations. These follow the Consolidated Standards for Reporting Trials (CONSORT) format, acting as an extension of the CONSORT guidelines for the specific requirements of acupuncture studies. Participating journal editors are publishing the STRICTA recommendations and requesting prospective authors to adhere to them when preparing reports for publication. Other journals are invited to adopt these recommendations. The intended outcome is that interventions in controlled trials of acupuncture will be more adequately reported, thereby facilitating an improvement in critical appraisal, analysis and replication of trials.

Acupuncture Therapy↗

PubMed2002

Hybridization parameters revisited: solutions containing SDS.

Salt concentration governs nucleic acid hybridization according to the Schildkraut-Lifson equation. High concentrations of SDS are used in some common protocols, but the effects of SDS on hybridization stringency have not been reported. We investigated hybridization parameters in solutions containing SDS. With targets immobilized on nylon membranes and PCR- or transcription-generated probes, we report that the 50% dissociation temperature (Tm*) in the absence of SDS was 15 degrees C-17degrees C lower than the calculated Tm. SDS had only modest effects on Tm* [1% (w/v) equating to 8 mM NaCl]. RNA/DNA hybrids were approximately 11 degrees C more stable than DNA/DNA hybrids. Incomplete homology (69%) significantly reduced the Tm* for DNA/DNA hybrids (approximately /4degrees C; 0.45 degrees C/% nonhomology) but far less so for RNA/DNA hybrids (approximately 2.3 degrees C; approximately 0.07 degrees C/% non-homology); incomplete homology also markedly reduced the extent of hybridization. On these nylonfilters, SDS had a major effect on nonspecific binding. Buffers lacking SDS, or with low salt concentration, gave high hybridization backgrounds; buffers containing SDS, or high-salt buffers, gave reproducibly low backgrounds.

DNA Probes↗