The authorities so far have arrested 11 of those charged on Wednesday as part of a federal effort to crack down on fraud in the program that provides health care for older people. The charges involved false billing by medical clinics across the city.

The Sapien, made by Edwards Lifesciences, offers an option for patients who are too old or frail for the current procedure.

Financial conflicts have surfaced among members of three groups that are developing major public health standards on hypertension, cholesterol and obesity.

Researchers have found that cleansing the body of a special category of cells could postpone many of the diseases that come with aging.

A Dutch scholar was found to have falsified findings in dozens of papers, in a field that critics say is vulnerable to such abuses.

Mindfulness, or being fully present and attentive to the moment, not only improves the way doctors engage with patients but also mitigates the stresses of clinical practice.

Scientists have been studying the effects of lower-nicotine test cigarettes on smokers in an attempt to get them to quit.

Some specialists are taking a stand against overreliance on the scans, saying they are easily misinterpreted.