Nitrous
oxide does not up heart attack risk during surgery
Washington:
Nitrous oxide - best known as laughing gas - has been one of the world`s oldest
and most widely used anaesthetics.
However,
despite its popularity, experts have questioned its impact on the risk of a
heart attack during surgery or soon afterward. But those fears are unfounded, a
new study by researchers at Washington University School of Medicine in St.
Louis suggests.
"It`s been known for quite a while that laughing gas
inactivates vitamin B12 and, by doing so, increases blood levels of the amino
acid homocysteine," lead author Peter Nagele, MD, assistant professor of
anesthesiology and genetics, said.
"That was thought to raise the risk of a heart attack
during and after surgery, but we found no evidence of that in this study,"
he said. Nitrous oxide normally is used as an adjunct during general anesthesia
because by itself the drug isn`t strong enough to keep patients unconscious
during surgical procedures.
The drug`s influence on B vitamins and homocysteine is unrelated to its anesthetic effects.
Nagele and his colleagues followed 500 surgery patients at Barnes-Jewish Hospital in St. Louis who had been diagnosed with coronary artery disease, heart failure or other health problems that could contribute to a heart attack.
All subjects in the study had noncardiac surgery and received nitrous oxide anesthesia.
The patients were divided into two groups. Half received intravenous vitamin B12 and folic acid to help prevent homocysteine levels from rising during surgery. The others did not get the intravenous B vitamins.
"There were no differences between the groups with regard to heart attack risk," Nagele said.
"The B vitamins kept homocysteine levels from rising, but that didn`t influence heart attack risk," he added.
The findings are set to be published in the journal Anesthesiology.
21.06.2013
Calcium and
vitamin D intake timing may affect how bone adapts to exercise
Washington:
Taking calcium and vitamin D before exercise may influence how bones adapt to
exercise, according to a new study.
The study
lead author Vanessa D. Sherk, PhD, postdoctoral research fellow at the
University of Colorado Anschutz Medical Campus, the timing of calcium
supplementation, and not just the amount of supplementation, may be an
important factor in how the skeleton adapts to exercise training.
In the study, which included 52 men aged 18 to 45 years, investigators found that an exercise-induced decrease in blood calcium occurred whether calcium supplements were taken before or after exercising.
In the study, which included 52 men aged 18 to 45 years, investigators found that an exercise-induced decrease in blood calcium occurred whether calcium supplements were taken before or after exercising.
Pre-exercise
supplementation, however, resulted in less of a decrease.
Although not statistically significant, parathyroid hormone
levels increased slightly less among cyclists who took calcium before
exercising.
"Taking calcium before exercise may help keep blood levels more stable during exercise, compared to taking the supplement afterwards, but we do not yet know the long-term effects of this on bone density," Sherk said.
The timing of calcium supplementation did not cause a difference in blood levels of a compound that is a biological indicator of bone loss.
Both the before- and after-exercise groups exhibited 50-percent increases in the level of this compound, called CTX, for collagen type-1 C-telopeptide.
The study will be presented at The Endocrine Society`s 95th Annual Meeting in San Francisco.
21.06.2013
Sometimes your joy is the source of your smile, but sometimes your
smile can be the source of your joy
Thich Nhat Hanh
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