Histone H3K27 trimethylation inhibits H3 binding and function of SET1-like H3K4 methyltransferase complexes.

Trimethylated histone H3 lysine 4 (H3K4) and H3K27 generally mark transcriptionally active and repressive chromatins, respectively. In most cell types, these two modifications are mutually exclusive, and this segregation is crucial for the regulation of gene expression. However, how this anticorrelation is achieved has not been fully understood.

A pilot scheme for improving the accuracy of serum cholesterol measurement in Scotland and Northern Ireland.

The measurement of plasma cholesterol is subject to particularly stringent requirements of bias and imprecision because clinically important action limits lie within the bulk of the population distribution. A pilot scheme was conducted with the aim of improving the accuracy of the assay of cholesterol in 26 laboratories in Scotland and Northern Ireland. This involved the distribution of three sets of authentic human sera with varying cholesterol concentrations assigned by the reference Abell-Kendall method which was established and validated in a central laboratory.

Plasma triglyceride and low density lipoprotein metabolism.

This study examines the relationship between plasma triglyceride and low density lipoprotein (LDL) levels by measuring the turnover of the native and 1,2 cyclohexanedione-treated lipoprotein in 25 healthy adults. Plasma triglyceride showed a strong positive correlation with circulating LDL apoprotein (apo LDL) mass. In order to achieve a satisfactory fit to the kinetic data it was necessary to postulate the existence of two plasma apo LDL pools (A and B).

Short-term changes in lipoproteins and apoproteins during cyclical oestrogen-progestogen replacement therapy.

Lipoproteins and apoproteins were measured weekly in a group of 18 post-menopausal women treated with a cyclical hormone replacement regimen comprising 28 days on conjugated equine oestrogens (0.625 mg/day) with the addition of norgestrel (0.15 mg/day) for the last 12 days of the cycle.

A comparison of commercial kits for the measurement of lipoprotein(a).

Five commercial kits for the assay of lipoprotein(a) were investigated and two of these, the Immuno Enzyquick and Biopool TintElize, both enzyme-linked immunoassays, were studied in detail. Whilst there was a strong correlation between the results obtained using the two methods there was a significant difference between the absolute values. In view of its higher precision at low levels and robust performance, the Enzyquick kit (Immuno Ltd) was selected for use in this laboratory.