Minerva

Should doctors wear white coats? Most patients, especially older ones, would apparently rather see doctors wear white coats as a way of identifying who they are. Most doctors, on the other hand, perceive them as an infection risk and find them uncomfortable (Postgraduate Medical Journal 2004;80: 284-6). Minerva wonders if the infection risk would seem as great if coats were exchanged for clean ones every day.

Let them eat yoghurt. Graft versus host disease after transplantation results not only from a reaction between the donor and recipient cells, but also from triggers such as cytokines, which are produced in response to bacteria. To reduce the risk of the disease, many transplant units use gut decontamination regimens. But one team tried yoghurt containing lactobacillus in mice models and found that the outcome was improved and graft versus host disease reduced in the yoghurt fed mice compared with mice receiving antibiotics and control mice (Blood 2004;103: 4365-7).

Injecting knees with intra-articular saline after arthroscopy seems to produce good pain relief. Not only that, but a randomised double blind study showed that injecting 1 ml of saline was just as effective as injecting 10 ml ( Anesthesia and Analgesia 2004;98: 1546-51). The authors suggest the finding of such a major placebo effect may have implications for the interpretation of previously published placebo controlled studies of intra-articular analgesia.

Children who watch a lot of television are also prone to obesity. It probably happens because children often eat in front of the box, and because of the success of advertising food on television. A survey of what children eat, and when, found that a substantial proportion of children's daily energy intake is consumed while watching television, and that eating high fat foods on weekends may be associated with increased body mass index in younger children (American Journal of Clinical Nutrition 2004;79: 1088-94).

A study of randomised controlled trials published in major international medical journals concludes that they under-represent much of the global burden of disease (Canadian Medical Association Journal 2004;170: 1673-7). Of 286 trials examined, less than half addressed any of the 35 leading causes of mortality and disability, and only one in six was thought to be highly relevant to global health The most studied conditions were HIV infection and vascular disease.

To date, the only drug with any prophylactic efficacy for chronic tension headaches is amitriptyline, which offers a success rate of about 30% reduction in headaches. Another, newer, antidepressant that is better tolerated can now be added to the armamentarium. In a small randomised, double blind, placebo controlled crossover trial mirtazapine produced better results in terms of duration and intensity and was well tolerated (Neurology 2004;62: 1706-11).

Minerva often has bad hair days, and the situation's not helped by having hair that frizzes at the least whiff of moisture. A possible genetic explanation for some of her problems is found on www.pnas.org/cgi/doi/10.1073/pnas.0402802101. The “frizzled” family of genes controls hair and bristle orientation in the fruit fly and mice, and it is now thought that similar genes may be responsible for human hair patterns such as cowlicks and whorls, which in turn have been linked with handedness.

“It's easier to change your own behaviour than to change somebody else's,” although this doesn't fit with the criticism often levelled at public health, that it's hell bent on telling other people what to do. Words of wisdom in the Journal of Epidemiology and Community Health (2004;58: 506)suggest that, in order to hold credibility in the wider world, health and healthcare sectors need to set an example in putting their own houses in order with regard to policies and practices.

When patients stop taking omeprazole they often report a recurrence of their symptoms, sometimes worse than before. The phenomenon of short term rebound acid secretion is recognised in people not infected with Helicobacter pylori, and a study in Gastroenterology (2004;126: 980-8)shows that this phenomenon can be prolonged. Ironically, patients positive for H pylori don't seem to get this, and if they're given eradication therapy, rebound acid secretion hits back with a vengeance.

Recognising that not everyone likes the same sort of music but that listening to it can reduce stress, researchers in Hong Kong got patients to listen to music of their own choice in reclining chairs while waiting for day case surgery (Journal of Clinical Nursing 2004;13: 297-303). Compared with the control group, who undertook the usual relaxing activities provided in the waiting room, the intervention group reported significant lower anxiety levels while waiting. Physiological parameters, however, were similar in both groups.

Pyoderma gangrenosum is a necrotising condition causing skin ulceration. Our patient presented after a total hip replacement with an ulcer over her operation scar (left figure). Wound swabs and blood cultures showed no growth, and the ulcer extended despite high dose intravenous antibiotics. Biopsy supported the diagnosis of pyoderma gangrenosum. The patient made a complete recovery with oral prednisolone, leaving a cribriform scar (right figure). Pyoderma gangrenosum displays pathergy, occurring insites of trauma. The patient had rheumatoid arthritis, a condition associated with pyoderma gangrenosum. The diagnosis should be considered in non-healing sterile ulcers, particularly when other risk factors are present.

J M L White, specialist registrar, L C Fuller, consultant department of dermatology, King's College Hospital, London SE5 9RS, G Groom, consultant department of orthopaedics, King's College Hospital

It's bad news for men. A study from California concludes that some of the same risk factors for heart disease also predict erectile dysfunction. Taking a prospective view of community based men aged 30-69 and following them up 25 years later revealed that age, body mass index, and blood cholesterol and triglyceride concentrations were each significantly associated with an increased risk of erectile dysfunction. Smoking was marginally more common in those with severe dysfunction (Journal of the American College of Cardiology 2004;43: 1405-11.

Anxiety seems to have a huge impact on the outcome of treating depression. In a group of patients with a major depressive disorder treated with fluoxetine, those who were subsequently switched to placebo and who were in the high anxiety subgroup were much more likely to relapse than those with lower level anxiety. Continuing treatment with the antidepressant produced a good outcome for both groups (Journal of Clinical Psychiatry 204;65: 373-8).

Guidance at bmj.com/advice