Biomedical subjects

Ian Henry

Publications and source records attributed to Ian Henry.

3 recordsLinked to original sources

PubMed2006

Signal enhancement in HPLC/microcoil NMR using automated column trapping.

A new HPLC NMR system is described that performs analytical separation, preconcentration, and NMR spectroscopy in rapid succession. The central component of our method is the online preconcentration sequence that improves the match between postcolumn analyte peak volume and microcoil NMR detection volume. Separated samples are collected on to a C18 guard column with a mobile phase composed of 90% D2O/10% acetonitrile-D3 and back-flushed to the NMR microcoil probe with 90% acetonitrile-D3/10% D2O. To assess the performance of our unit, we separated a standard mixture of 1 mM ibuprofen, naproxen, and phenylbutazone using a commercially available C18 analytical column. The S/N measurements from the NMR acquisitions indicated that we achieved signal enhancement factors up to 10.4 (+/-1.2)-fold. Furthermore, we observed that preconcentration factors increased as the injected amount of analyte decreased. The highest concentration enrichment of 14.7 (+/-2.2)-fold was attained injecting 100 microL of solution of 0.2 mM (approximately 4 microg) ibuprofen.

Chromatography, High Pressure Liquid↗

PubMed2006

Predicting gene expression level from codon usage bias.

The "expression measure" of a gene, E(g), is a statistic devised to predict the level of gene expression from codon usage bias. E(g) has been used extensively to analyze prokaryotic genome sequences. We discuss 2 problems with this approach. First, the formulation of E(g) is such that genes with the strongest selected codon usage bias are not likely to have the highest predicted expression levels; indeed the correlation between E(g) and expression level is weak among moderate to highly expressed genes. Second, in some species, highly expressed genes do not have unusual codon usage, and so codon usage cannot be used to predict expression levels. We outline a simple approach, first to check whether a genome shows evidence of selected codon usage bias and then to assess the strength of bias in genes as a guide to their likely expression level; we illustrate this with an analysis of Shewanella oneidensis.

Codon↗

PubMedDate not supplied

Lymecycline in the treatment of acne: an efficacious, safe and cost-effective alternative to minocycline.

A comparison of efficacy, safety and cost-effectiveness of lymecycline and minocycline in the treatment of acne vulgaris has been addressed. This was a multicenter, randomized, investigator-masked, parallel group trial involving patients with moderate to moderately severe acne vulgaris, receiving either lymecycline or minocycline for 12 weeks. Efficacy and safety evaluation was performed at baseline and at weeks 4, 8, and 12 and completed by a pharmacoeconomic analysis including week 12 data. One hundred and thirty-six patients were enrolled. At week 12, the mean percent reductions in inflammatory count were 63 % and 65 %, and for total lesions counts 58 % and 56 % for lymecycline and for minocycline respectively. Median percent reduction in non-inflammatory count were 54 % and 47 % for lymecycline and for minocycline respectively. Eighty-seven per cent of all patients tolerated the treatments well. Treatment with lymecycline was found to be 4 times more cost-effective than with minocycline. Results showed that lymecycline has a comparable efficacy and safety profile to minocycline while being 4 times more cost-effective.

Acne Vulgaris↗