Kiss and tell: why we pucker up
Physiology
Next week, kisses will be exchanged on cards, in boxes of candy -- and, of course, on the lips. Scientists know how humans kiss and what happens to the body during a kiss, but why people began puckering up in the first place remains unknown.
A romantic kiss, blandly stated, involves movement of the lower jaw (the sole movable bone in the head) and contraction of 34 muscles in the face, neck and head -- principally the orbicularis orbis, which surrounds the mouth and allows the lips to pucker.
Nerve endings abundant in the lips and on the tongue rush signals to the brain, triggering a cascade of events. Blood rushes to the lips, and the body warms. Saliva pours out of glands (which is why kisses are wet), blood testosterone levels surge, and feel-good chemicals such as endorphins and oxytocin are released in the brain.
Blood pressure rises, the heart rate accelerates from about 70 to upward of 120, and calories begin to burn at a rate of about 6 a minute compared with just over 1 calorie per minute when someone's sitting and reading or watching TV.
Researchers don't know when or why kissing originated, but theories abound. Freud speculated (as could be expected) that kissing was a return to suckling at the breast. Some anthropologists and animal behaviorists have proposed that kissing may have evolved from sniffing, based on observations of people -- and many species of animal -- that rub noses or smell each other in greeting.
Others suspect that the pucker evolved from mouth-to-mouth feeding, sometimes called "kiss feeding." Think of mama bird feeding her nest of baby birds -- and imagine that our distant evolutionary ancestors did something similar. Then imagine that, over time, our hominid ancestors lost the need to join lips for feeding but kept joining lips for fun.
Los Angeles Times
Dermatology
Scratching an itch may suppress unpleasant emotions and memories
Skin ointments to relieve chronic itching often ease -- but don't completely stifle -- the urge to scratch. Now scientists think they know why.
Researchers at Wake Forest University Baptist Medical Center in North Carolina used magnetic resonance imaging to look at the brain activity of 13 healthy volunteers while they were scratched on a lower leg with a small brush. The study found that scratching muted activity in parts of the brain associated with unpleasant emotions and memories. What that means, says lead author Gil Yosipovitch, is that scratching may suppress the emotional connection to the itch -- even if it's not addressing the cause.
The study, published in the Journal of Investigative Dermatology, suggests it will take more than topical remedies to cure itchy skin. "The skin sends messages to the brain, and the brain sends them back. It's one of those marriages of body and mind," says Yosipovitch, a dermatologist. "You need to target the neuro system, not just the skin."
The study also showed increased activity in other parts of the brain, such as the prefrontal cortex, which is linked to compulsive behavior. That might explain why, once people start scratching, they can find it hard to stop.
Los Angeles Times
Asthma
Inhaled steroid treatment for children gets FDA approval
A new inhaled steroid treatment for preventing asthma attacks in young children has been approved by the Food and Drug Administration, the drugmaker Schering-Plough Corp. said Monday.
Its Asmanex Twisthaler is the first once-a-day, inhaled corticosteroid medicine for asthma -- the most common chronic condition among children -- that can be taken by children as young as 4.
The Kenilworth, N.J.-based company got FDA approval two years ago to sell the product as a maintenance treatment to prevent asthma flare-ups in adults and children 12 and older. The dosage for children ages 4 to 11, 110 micrograms, is half the adult dose.
Competing products are approved for children as young as 6, or must be taken more times a day.
Asthma afflicts 7 percent to 10 percent of U.S. children younger than 18. It is blamed for more than 14 million missed school days and nearly 1 million emergency room visits by children each year, according to the Asthma and Allergy Foundation of America.
The new product should be available in the second half of 2008, said Schering-Plough spokeswoman Lisa Ellen.
Associated Press