Diabetes mellitus is one of the most important risk factors for cardiovascular diseases. The results of several studies have shown that achieving satisfactory glucoregulation results in a significant reduction in the incidence of microvascular and macrovascular complications, and cardiovascular mortality. However, the risk of the development of cardiovascular diseases is markedly increased in the presence of dyslipoproteinemia. Research has shown that hyperglycemia not only causes apoptosis of β-cells in the islets of Langerhans (glucotoxicity) but also determines the degree of accumulation of oxidized LDLs. On the other hand, dyslipoproteinemia itself has a toxic effect on β-cells, but only in the presence of increased blood glucose levels, thus increasing the risk of the development of cardiovascular diseases exponentially. As diabetes and the lipid metabolism disorder can be neither scrutinized nor treated separately, the authors query whether 'diabetes lipidus' would be a more appropriate term.

We report a novel pathogenic mutation of the mitochondrial transfer RNA (tRNA) gene for tryptophan in a patient with isolated myopathy and persistently elevated creatine kinase. Muscle studies revealed ragged red fibres and decreased activity of respiratory chain complex I and cytochrome c oxidase (COX). Sequencing of the 22 mitochondrial tRNA genes revealed a mutation m.5522G>A, which alters a conserved base pairing in the D-stem of the tRNA for tryptophan. The mutation was heteroplasmic with a mutational load between 88 and 99% in COX-negative fibres. This case contributes to the genetic heterogeneity of mitochondrial diseases caused by mutations in mitochondrial tRNA genes.

Summary Although the physiological function of serum butyrylcholinesterase (BuChE) has not yet been clarified, there is evidence that this enzyme is involved in serum lipoprotein metabolism. It has been suggested that serum BuChE is positively correlated with LDL (low-density lipoprotein) and negatively with HDL (high-density lipoprotein) levels. The objective of this study was to determine whether the activity of BuChE changes during treatment with simvastatin (CAS 79902-63-9). The effects of simvastatin therapy on serum lipoproteins and plasma BuChE activity were studied in 15 patients with type IIa and 17 patients with type IIb hyperlipoproteinemia. Beside the expected influence on serum lipid concentration, a statistically significant decrease in BuChE activity in patients with hyperli-poproteinemia type IIa and IIb during treatment with simvastatin was not observed.

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