People with high blood pressure are at increased risk of developing Alzheimer's disease, so perhaps it's not very remarkable that, in a study of an elderly population in Utah, use of antihypertensive drugs tended to reduce the risk (Archives of Neurology 2006;63: doi: 10.1001/archneur.63.5.noc60013). More interesting was the observation that different treatments varied in their protective effect. Diuretics, particularly potassium sparing diuretics, conferred the most protection. The investigators point out that, whereas both loop and thiazide diuretics reduce plasma potassium concentration, potassium sparing diuretics usually lead to increased concentrations.

Waste water flowing out of hospitals is potentially dangerous stuff. Out of a total of 38 samples taken from the main sewer of a French university hospital over a two year period, 31 were positive in at least one microbiological assay of genotoxicity. Samples taken on a Monday and during periods of low rainfall were most likely to show evidence of toxicity. Which of the many thousands of chemical compounds released from hospitals are to blame has yet to be established, but the researchers rate anticancer drugs and antimicrobials as prime suspects (Annals of Occupational Hygiene 2006;50: 189-96).

Minerva has a short attention span and sometimes finds articles in the New York Review of Books heavy going. But she was …