(HealthDay News) -- Children who witness or are involved in a tragedy may have symptoms of post-traumatic stress disorder, although symptoms may differ from those in adults.

(HealthDay News) -- Smokers may love the habit, but tobacco smoke doesn't love the heart.

THURSDAY, Aug. 25 (HealthDay News) -- In the event of a natural or man-made disaster, such as a tornado, earthquake or fire, most dialysis patients don't have a plan to get the medical assistance they need, according to a new study.

THURSDAY, Aug. 25 (HealthDay News) -- Your immune system response to a flu virus determines whether or not you will get sick, and that immune reaction can be observed through gene activity, according to a new study.

THURSDAY, Aug. 25 (HealthDay News) -- For kids, the end of summer means an abrupt end to staying up late and sleeping until noon: It also signals the beginning of brand new challenges and perhaps a case of the back-to-school jitters.

THURSDAY, Aug. 25 (HealthDay News) -- Rheumatoid arthritis patients who believe in their ability to achieve physical activity goals -- called self-efficacy -- are more likely to reach those objectives, researchers have found.

THURSDAY, Aug. 25 (HealthDay News) -- Interbreeding between modern humans, Neanderthals and another close relative may have passed on genes that boost peoples' immune systems today, researchers report.

THURSDAY, Aug. 25 (HealthDay News) -- A build-up of calcified plaque in arteries in parts of the body outside the brain may be linked with brain changes that increase the risk of stroke and dementia, a new study finds.

THURSDAY, Aug. 25 (HealthDay News) -- When a woman is diagnosed with a sexually transmitted infection such as chlamydia or gonorrhea, her doctor should be able to pass along antibiotics to her male partner without examining him, to cut both partners' odds of re-infection, experts say.

THURSDAY, Aug. 25 (HealthDay News) -- An exhaustive new report from experts at the Institute of Medicine finds that children's vaccines are typically safe, with bad reactions occurring only rarely and then not causing any lasting medical problems.

THURSDAY, Aug. 25 (HealthDay News) -- Alzheimer's disease is one of the most dreaded afflictions of old age, but the announcement by celebrated women's basketball coach Pat Summit of her Alzheimer's diagnosis at age 59 has put a spotlight on the less common, but perhaps even more devastating, form of the disease.

Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

THURSDAY, Aug. 25 (HealthDay News) -- Federal officials on Thursday continued to urge residents of the U.S. East Coast to make emergency preparations for Hurricane Irene, a "category 3" storm with winds up to 115 miles per hour.

THURSDAY, Aug. 25 (HealthDay News) -- Teen vaccination rates for human papillomavirus (HPV) are lagging behind rates for two other important vaccines in the United States, federal researchers say.

THURSDAY, Aug. 25 (HealthDay News) -- The number of obese people in the United States will increase from 99 million in 2008 to 164 million by 2030, and the number of obese people in the United Kingdom will increase from 15 million to 26 million, a new study predicts.

THURSDAY, Aug. 25 (HealthDay News) -- One of the hallmarks of Steve Jobs' tenure as CEO of Apple Inc. was the secrecy that shrouded products he was about to unveil -- from the iPod to the iPhone to the iPad -- creating tremendous consumer interest.

THURSDAY, Aug. 25 (HealthDay News) -- At many hospitals, stroke patients face higher odds of dying if they're admitted over the weekend rather than a weekday, but a new study finds equally good results for patients treated at comprehensive stroke centers.

THURSDAY, Aug. 25 (HealthDay News) -- Firazyr (icatibant) has been approved by the U.S. Food and Drug Administration to treat acute (severe) attacks of hereditary angiodema (HAE) in adults.

THURSDAY, Aug. 25 (HealthDay News) -- A new scoring system might be able to tell patients in the final stages of cancer how much time they have left so they can prepare for their passing, British researchers report.