Lab Report: Health, Science and Medicine

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New Guidelines for Diagnosing Allergies

Surveys suggest that the rate of food allergies is on the rise in the U.S., but experts say up to 90% of those allergies may be misdiagnosed cases of sensitivity to or intolerance of common foods like peanuts, milk and soy. So what exactly is a food allergy, and how widespread is the problem?

Those are questions that new guidelines from the National Institute of Allergy and Infectious Diseases and other groups are designed to answer. The recommendations, for both the diagnosis and management of food allergies, offer doctors a standardized set of tests to confirm an allergic reaction to food and help distinguish a true immunity-based food allergy from an intolerance to certain ingredients. The commonly used skin-prick and blood-antibody tests may identify sensitivities to certain foods, for instance. But only combining these tests with a food challenge, in which a child ingests a potentially problematic food in the doctor's office, can confirm a full-blown allergy. The guidelines also note that there is no evidence that avoiding allergy-provoking foods during pregnancy will reduce food allergies in newborns.


The Protective Effect of a Family's Love

For gay and lesbian teens, coming out to family members is often a challenging and stressful process. In the first research of its kind, a survey of 245 gay, lesbian, bisexual and transgender adolescents and their relatives shows just how powerful a family's acceptance and support can be in helping these teens avoid depression, suicide and substance abuse.

Among the teens in the study, those whose families showed more support--by openly discussing their child's sexual orientation, for instance, or attending gay or lesbian events--not only had more self-esteem but were also half as likely to have had suicidal thoughts or to have reported depressive symptoms in the previous six months of the study, compared with teens whose families were less accepting.

The researchers stress, however, that the less accepting families were not necessarily less loving. In fact, in many cases, these families were simply unaware that their well-intentioned behaviors--including efforts to change their child's sexual orientation--were actually hurtful and disrespectful of their children. A better understanding of supportive actions and their positive effects, say the authors, could help more families of gay and lesbian teens avoid the tensions that can lead to mental-health problems.


Birth Months and Biological Clocks

The season in which babies are born may set their biological clocks for life, according to a study in mice. Pups weaned in artificially created winter or summer light cycles and then placed in constant darkness showed that early exposure to winter light may trigger an exaggerated response to light changes later on. This could explain the higher rate of conditions like seasonal affective disorder in people born in winter.

The Genetic Gender Switch

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