Automatic external defibrillators (AEDs) are known to improve outcomes after out-of-hospital cardiac arrest when used by trained public-safety personnel. This study showed that the same is true when AEDs are used by trained laypersons in public locations, such as shopping malls and recreational facilities.

The findings of this trial encourage wider use of AEDs, but the public health effects are limited by the fact that most out-of-hospital cardiac arrests occur in private homes, not in public places.

Rapid defibrillation is the key intervention known to improve the outcome of out-of-hospital cardiac arrest. This study showed that the addition of advanced cardiac life support (endotracheal intubation and the administration of intravenous medications) to a program of rapid defibrillation did not further improve the outcome.

Survival to hospital discharge was 5 percent with or without advanced life support, so new approaches are urgently needed to address this major health care problem.

The mechanism of the progression of chronic myelogenous leukemia (CML) from the chronic phase to the blast phase is unknown. These researchers report the surprising finding of the expansion of a self-renewing population of granulocyte–macrophage precursors with amplification of the BCR-ABL gene and activation of the -catenin pathway.

This investigation opens unexpected avenues of research on the evolution of CML and focuses attention on a novel therapeutic target.

About 1 out of 100 children who are stung by an insect from the order Hymenoptera has a systemic allergic reaction. Although it has been suggested that children may outgrow these reactions, there are few data on this subject. These investigators provide descriptive follow-up data on a large group of children with systemic allergic reactions to an insect sting, including children treated with venom immunotherapy. Although many children outgrew the allergy, many did not. Some protection due to immunotherapy was apparent 10 to 20 years later.

During a routine visit, a 59-year-old woman, who describes herself as a lifetime "worrier" and has a family history of depression, reports having restless sleep, muscle tension, and fatigue. Recently, her worry has intensified about her children, her job, and her health, and it is having a negative effect on her family and work life. How should she be treated?

Von Willebrand's disease is an inherited bleeding disorder with a prevalence as high as 1 to 2 percent in the general population, according to screening studies. However, its prevalence is deemed to be only 30 to 100 cases per million on the basis of symptomatic referrals, a prevalence that is similar to that of hemophilia A. This article discusses major advances in our understanding of the pathophysiology, molecular basis, and management of von Willebrand's disease.

A 49-year-old woman was evaluated for weight-loss surgery. She had been obese since late childhood, and her current body-mass index was 52. She had been unable to maintain weight loss by dieting and had both diabetes and hypertension. The multidisciplinary team discusses the surgical management of obesity.