The proof is molecular

Potentially serious patient identification errors in pathology samples may be resolved using molecular confirmation, according to the results of an Australian study. Researchers investigated 14 cases of suspected pathology sample misidentifications and mix-ups arising in public and private laboratories. Most of the 23 individual samples from these cases were prostate tissue, with some other tissue biopsies and a haematological sample. The identification tests were performed with the forensic ABI Identifiler kit on DNA from paraffin-embedded tissues or blood specimens. Six of the 23 specimens were found to be discordant, indicating that an identification error had occurred. The authors comment that the high sensitivity of forensic identity multiplex systems, which use either single nucleotide polymorphisms or microsatellites, makes these tests ideal for resolving problems with identification of pathological specimens.

Pathology 2009; 41: 280-283

HDL, glucose, and diabetes

The evidence is clear that high-density lipoprotein (HDL) is associated with a decreased risk of harmful cardiovascular outcomes, and that low plasma levels of HDL are seen in type 2 diabetes and the metabolic syndrome. A group of Australian and Danish researchers have set out to find the key to the mechanism behind this observation. They hypothesised that HDL has a role in modulating glucose metabolism by elevating plasma insulin and activating the metabolic regulatory enzyme, AMP-activated protein kinase, in skeletal muscle. In a double-blind crossover study, participants with type 2 diabetes were given intravenous HDL and a placebo on separate days, and plasma glucose and insulin were measured. Activation of skeletal muscle AMP-activated protein kinase was assessed by biopsy. HDL infusion was associated with a significant fall in plasma glucose, increased plasma insulin, and increased muscle cell enzyme activity. Associated in-vitro studies of pancreatic and skeletal muscle cell lines confirmed the effects of HDL. The authors comment that the effect of therapies aimed at raising HDL should be examined in large trials measuring metabolic parameters such as glucose and insulin.

Circulation 2009; 119: 2103-2111

Burnt out and on benefits

It seems stress at work can not only make you sick, it can result in a life of dependence as well. Occupational burnout appears to be a predictor of eventual permanent work disability and dependence on a disability pension, say Finnish researchers. Burnout was defined in the study as a combination of exhaustion, doubts about the value of one’s work (cynicism) and competence (diminished professional efficacy). After adjusting for baseline health and sociological factors, workers with burnout were significantly more likely to be on a disability pension in the future. The pension was most likely to be granted on the basis of mental and behavioural disorders and musculoskeletal diseases. The authors conclude that working conditions and burnout need to be assessed regularly in the work environment to prevent early losses from the workforce.

Occup Environ Med 2009; 66: 284-290

Sugar Tax

A tax on sugar-sweetened beverages would have a huge impact on consumption and thus result in major benefits to public health, say the authors of a recent US perspective that is sure to generate debate. Citing the success of taxes on tobacco products, they quote cost analyses which suggest that for every 10% increase in price, consumption of sweetened carbonated drinks decreases by 7.8%. In a detailed discussion of the ethics and benefits of, and opposition to, such taxes on sugared beverages, the bottom line appears to be that, although it might be unpopular, the magnitude of the result would far outweigh that achieved through education campaigns alone. Finally, they comment that the revenue thus generated could be directed to efforts to improve public health.

N Engl J Med 2009; 360: 1805-1808

Dr Tanya Grassi, MJA

©The Medical Journal of Australia 2009 www.mja.com.au PRINT ISSN: 0025-729X ONLINE ISSN: 1326-5377