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Vol. LXII, No. 19
September 17, 2010
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Digest

  An NIH-funded study has shown that a lower blood pressure goal helps African Americans with chronic kidney disease and protein in the urine, which is a sign of kidney damage.  
  An NIH-funded study has shown that a lower blood pressure goal helps African Americans with chronic kidney disease and protein in the urine, which is a sign of kidney damage.  

Lower Blood Pressure Goal Helps African Americans with Chronic Kidney Disease, Protein in the Urine

On average, a lower blood pressure goal was no better than the standard blood pressure goal at slowing progression of kidney disease among African Americans who had chronic kidney disease resulting from high blood pressure, according to results of the African- American Study of Kidney Disease and Hypertension (AASK), the largest and longest study of chronic kidney disease (CKD) in African Americans. However, the blood pressure goal did benefit people who also had protein in the urine, which is a sign of kidney damage. The NIH-funded study appeared in the Sept. 2 issue of the New England Journal of Medicine.

AASK also found that among people with protein in their urine, keeping blood pressure at the lower level reduced the likelihood of kidney disease progression, kidney failure or death by 27 percent compared to the standard blood pressure level, a statistically significant difference. AASK adds new information about which CKD patients benefit from lowering of blood pressure. This information may help doctors practice evidence-based, personalized medicine, the tailoring of each treatment regimen to each patient’s unique characteristics. AASK followed participants for approximately 12 years to measure the long-term effects of blood pressure control in African Americans with kidney disease attributed to high blood pressure.

Elevated Levels of Lead, Cadmium Found to be Associated with Delayed Puberty

Researchers at NIH and other institutions have found that exposure to lead in childhood may delay the onset of puberty in young girls, with higher doses increasing the chance for later maturation.

The researchers analyzed data on blood drawn from more than 700 girls ages 6 to 11. They found that girls with elevated levels of lead (at or above 5 micrograms of lead per deciliter of blood) were 75 percent less likely than girls with low levels of lead to have key adolescent hormones at levels that are associated with the beginning of puberty. In girls with elevated levels of both lead and cadmium, this pattern was even more pronounced.

The researchers speculate that lead, alone or in concert with cadmium, might suppress the ovary’s production of hormones that prepare a young girl’s body to ovulate, or release an egg, for the first time. Their work was published July 30 in Environmental Health Perspectives.

“Our findings suggest childhood exposure to lead has worrisome effects as children age and reach adolescence,” said lead author Dr. Audra L. Gollenberg of NICHD, where the research was conducted. “These issues are of concern in some parts of the United States as well as in countries where children are exposed to leaded gasoline, paint or industrial pollutants.”

Third-Generation Map of Human Genetic Variation Published

An international consortium has published a third-generation map of human genetic variation, called the HapMap, which includes data from an additional 7 global populations, increasing the total number to 11 populations. The improved resolution will help researchers interpret current genome studies aimed at finding common and rarer genetic variants associated with complex diseases. NHGRI provided major funding for the HapMap Project.

Any two humans are more than 99 percent the same at the genetic level. But, the small fraction of genetic material that varies among people can help explain individual differences in susceptibility to disease, response to drugs or reaction to environmental factors. Variation in the human genome is organized into local neighborhoods called haplotypes, which usually are inherited as intact blocks of DNA sequence information. Consequently, researchers refer to the map of human genetic variation as a haplotype map, or HapMap.

The first- and second-generation versions of HapMap resulted from the analysis of DNA collected from 270 volunteers from four geographically diverse populations: Yoruba in Ibadan, Nigeria; Japanese in Tokyo; Han Chinese in Beijing; and Utah residents with ancestry from northern and western Europe.

The third-generation HapMap, reported in the Sept. 2 issue of Nature, is the largest survey of human genetic variation performed thus far. It has data on 1,184 people, including the initial HapMap samples. Additional human samples were collected from the original populations and from 7 new populations.


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