News in brief - April 28, 2003

Human genome fully sequenced - Antidepressant use by new mothers does not affect infant weight gain - Prescribing exercise to patients can increase physical activity, well-being - Keep potassium iodide handy if a nuclear plant is nearby

Human genome fully sequenced

The National Human Genome Research Institute announced that the reference sequence of the human genome is finished.

NHGRI, part of the National Institutes of Health, led the International Human Genome Sequencing Consortium, which included hundreds of scientists at 20 centers around the world. A first draft of the human genome was released in June 2000. A final versi on was not expected until 2005. But, a combination of competition and improved technology led to completion of the undertaking two years early.

"The Human Genome Project has been an amazing adventure into ourselves, to understand our own DNA instruction book, the shared inheritance of all humankind," said NHGRI Director Francis S. Collins, MD, PhD.

The Institute also revealed their vision for the future of genomic research and published it in the April 24 issue of Nature, coinciding with the 50th anniversary of the publication of a paper by James Watson, PhD, and Francis Crick, PhD, descri bing DNA's double helix. The NHGRI paper calls for researchers to work toward new methods for the early detection of disease and new technologies that can sequence an individual's genome for less than $1,000.

"Achieving the goals of the Human Genome Project is a historic milestone. But this is not time to rest and relax," said Dr. Collins.

Antidepressant use by new mothers does not affect infant weight gain

Infants breastfed by depressed mothers not being treated for their illness gain less weight than those breastfed by mothers taking antidepressants for their condition, according to a study published in the April Journal of Clinical Psychiatry.

Researchers at the University of California, Los Angeles, who studied 78 new mothers who took antidepressants while pregnant, also found that children of mothers who took their medication had normal development comparable to the average infant, based o n Centers for Disease Control and Prevention data.

"Our study showed no evidence that children's physical development is harmed by exposure to antidepressants through breast milk, whereas there is evidence that children are harmed by exposure to maternal depression," said Victoria Hendrick, MD, lead au thor and director of the Pregnancy and Postpartum Program at UCLA's Neuropsychiatric Institute.

Prescribing exercise to patients can increase physical activity, well-being

Verbal advice and written "exercise" prescriptions from a physician, followed by telephone and mail support by exercise specialists, can increase physical activity and quality of life, according to a study published in the British Medical Journal this month.

During a one-year period, researchers at the University of Auckland studied more than 800 sedentary patients, ages 40 to 79, in both rural and urban areas in New Zealand. Those who received the intervention increased their physical activity by an avera ge of 34 minutes per week. About 15% of study participants increased their activity level to 2½ hours per week, and patients improved their overall vitality and mental health. Researchers also noted lower blood pressures, although this was not statistical ly significant. There was also no change to the long-term risk of heart disease.

Researchers stated that this study shows that exercise-related interventions in a general practice setting can be effective.

"If implemented widely, such a strategy could result in major health benefits for sedentary people," wrote the researchers.

Keep potassium iodide handy if a nuclear plant is nearby

The American Academy of Pediatrics recommends that households, schools and child care facilities within 10 miles of a nuclear power plant keep potassium iodide (KI) on hand to protect the thyroid in the event of exposure to radioactive iodines.

It may even be prudent to stockpile KI within a larger radius in case the wind carries the fallout further, said the AAP in a new policy statement.

Children are considered much more vulnerable to the harmful effects of radiation than are adults because children's bodies absorb and metabolize substances differently and because they are closer to the ground where radioactive fallout settles.

KI blocks the thyroid's absorption of radiation and can prevent thyroid cancer, said the pediatricians. If administered right before exposure to radioiodines, KI can be 100% effective at preventing harmful effects, and for that reason it should be quic kly available. Its effectiveness diminishes somewhat if administered later.

KI is not effective in preventing long-term radiation effects, such as leukemia and breast cancer, said the group.