Stories tagged heart
Music for the heart
Courtesy Public domainThat's right - the Bee Gees, the Brothers Gibb, those high-pitched Kings of the Disco Era! Well, to tell the truth it's not really the Bee Gees, per se, but rather one of their songs - the classic (and in this case appropriate) "Stayin' Alive". Researchers at Illinois College of Medicine have determined that the number of beats in that particular song (103 per minute) is almost exactly the number you want to count out while performing cardiopulmonary resuscitation (CPR) on someone. Bottom line: if you have that song looping through your head while you're doing heart compressions on a heart attack sufferer, you'll keep the recommended per minute rhythm and triple the victim's chances of survival. Read more here.
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Working better and better: Statistically, our hearts are getting better and better. The rate of heart-related deaths is dropping faster than goals set by by national health organizations.
Courtesy wikipediaHere’s something to strengthen your heart in advance of Valentine’s Day. Nationally, our rates for heart attack and stroke deaths have dropped faster than the pace national health organizations hope we’ll be at in 2010.
Over the period from 1999 to 2005, heart disease deaths dropped 25.8 percent while stroke deaths dropped 24.4 percent. That means that 160,000 people are still alive today who statistically would have likely died from heart and circulation trouble in the past year. If those rates continue, we’ll have an extra 240,000 people living a year from now who in past years would have died from heart ailments.
However, while our hearts are getting healthier epidemics continue on the diabetes and obesity fronts. And health problems associated with those factors could offset the decreased deaths from heart troubles.
The National Center for Health Statistics released the analysis of these health findings, but didn’t issue any causes for the changing mortality rates. So I put it to you, why are people having better heart health? Better diets? Decreased smoking? More exercise? Share your thoughts here with Science Buzz readers.
Decellularization: A rat heart as the cells are removed (left three images) and replaced (right two images) over time.
Courtesy Thomas Matthiesen, University of Minnesota
Science fiction?
Did you know that nearly 5 million people live with heart failure? More surprisingly, approximately 50,000 United States patients die annually waiting for a donor heart.
University of Minnesota researchers recently announced they have created a beating heart in the laboratory. It sounds like science fiction, but it is a real medical breakthrough. The researchers removed the tissue from a dead rat heart and replaced it with living cells from newborn rats. With the help of electrical signals, the entire heart began to beat.
"Ghost hearts"
The researchers used a detergent to remove the cells from the rat hearts. This left behind only the nonliving fibers that give the heart its shape. The result was a white, rubbery, 3-D “skeleton”. This structure, called the extracellular matrix, allows cells to attach and grow into tissue, and gives the heart muscle something to pull against. The researchers injected cells from newborn rats into the left ventricle and pumped oxygen and nutrients through the structure of blood vessels. They helped the process by sending electrical signals through the new tissue. In eight days, the hearts were pumping – some continued beating for 40 days.
The supply of donor organs is limited and the risks for infection or rejection of the transplanted organ can be high. If the technique is perfected, doctors may be able to use patients’ own stem cells to recellularize a donor heart.
The next steps
The University of Minnesota research team has successfully decellularized pig hearts, and hopes that other types of organs can be created in the future.
Dead heart transformed into a living heart
Tissue engineering has allowed a dead rat heart to be stripped of its cellular material, then after injecting the remaining scaffold material with with new cardiac cells, the cells organized themselves until the heart became alive.
A "crazy idea" at the University of Minnesota that could not get federal funding yielded "unbelievable" results after getting funding from the University of Minnesota and from the Medtronic Research Foundation.
New source for replacement organs
The accomplishment gave a significant boost to medicine’s dream of growing human organs to replace damaged ones. Organ transplants usually require replacement organs that fulfill extreme compatibility issues. By using the patients own cells in the rebuilt organs scientists hope to eliminate the need for patients to take anti-rejection drugs for the rest of their lives.
Growing human hearts at least 10 years away, if ever
The next step will be to use these techniques on pig hearts. Pig hearts are similar enough to a humans that parts from them have already been used in humans.
"Although this is only a first step requiring considerable follow-up development, the study nevertheless represents an exciting breakthrough that will eventually make the prospect of repairing damaged hearts a reality and will also be an approach that can be extended to other organs." Dr Jon Frampton Wellcome Trust Senior Fellow at the University of Birmingham
Source articles
TwinCities.com
New York Times
BBC News
USA Today
Nature Medicine journal's Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart (abstract)
A European study has found that women taking oral contraceptives (birth control pills) are at a higher risk for blood clots and heart disease.
Doctors in Israel have created beating heart tissue from stem cells. However, some commenters at this medical blog are underwhelmed.
A recent study in Poland showed that a flu shot can significantly reduce the risk of death for people with coronary artery disease. Dr. Arnold Monto, professor of epidemiology at the University of Michigan, said,
"We know that people die of flu who have underlying cardiopulmonary disease. It's only logical that if you are able to prevent flu with vaccine, you can prevent these deaths."
On May 11, 1987, doctors in Baltimore transplanted the heart and lungs of an auto accident victim to a patient who gave up his own heart to a second recipient. Clinton House, the nation's first living heart donor, died 14 months later. Want to know more about organ or body donation? Check the Buzz next week for a new feature!
Veggies: Vegetables are an important part of a low fat diet. Image courtesy Icarus Diving.
The Women's Health Initiative is a clinical trial sponsored by the National Heart, Lung, and Blood Institute, an institute of the National Institutes of Health. It included the largest ever study of a low-fat diet in postmenopausal women to see if such a diet reduced their rate of contracting certain diseases. 48,835 women aged 50-79 participated for an average of 8 years. The results of the low-fat diet trial showed no significant reduction in the rate of breast cancer, heart disease, or stroke and no effect on the risk of colorectal cancer. However, the women in the study had trouble sticking to the recommended amount of daily fat and they did not necessarily cut out the types of fat considered most harmful (saturated fats and trans fats).
What About Nutritional Supplements?
The study also followed 36,282 women of the same age range to find out if calcium and vitamin D supplements reduced the rate of broken bones from osteoporosis. Again the results appeared to show no appreciable advantage to taking the supplements, although there was an average of 1% gain in bone density.
X-Ray: Osteoporosis can lead to broken bones. Image courtesy Retrogradeheart.
Drop the Supplements and Forget the Low-Fat Diet?
Researchers found that the trend in positive results was going upwards for the group on the low fat diet enough to encourage the researchers that continued monitoring of the women over the next few years will show a positive result. And people connected with the calcium/vitamin D supplement study say that despite the slightly elevated risk of kidney stones that was seen in some women, the overall gain in bone density was great enough to make a difference for some women and to have a positive impact on money spent on health care for osteoporosis-related injuries.
The upshot is that there are still opportunities to learn more information about how diet and supplements affect the health of these postmenopausal women, including why some subgroups of women were affected in ways that others weren't. Doctors and researchers aren't changing their overall advice yet, although people should always discuss their diets with their doctors as cases can differ from person to person.
Race-based medicine?
in Life Science, History and Nature of Science, Scientific Inquiry, and Human Organism
Yesterday, an advisory panel for the Food and Drug Administration (FDA) recommended approval of a drug, BiDil, for heart failure in African-Americans. (The approval was unanimous, although two panel members voted against the racial indication labeling for the drug.) If the FDA follows the panel's advice, BiDil will become the first drug approved for use by patients of a particular race. The drug is a combination of two generic drugs (isosorbide dinitrate-also known as nitroglycerine-and hyrdralazine) that works by increasing the body's concentration of nitric oxide, which widens the arteries and helps the heart function more efficiently. The drug was tested in 1,050 African-Americans last fall. In that study, patients taking BiDil had much better survival rates and were much less likely to be re-hospitalized for congestive heart failure. Dramatic outcomes like this are a good thing, right? Yes. But the idea that a drug be approved for patients of a specific race makes many doctors uncomfortable, and it may also be bad medicine. Jonathan Kahn, a law professor and medical ethicist at Hamline University, said:
"It sends the message that because [the study] was done only in African-Americans that somehow African-Americans are different genetically than everybody else. And that is a very dangerous message to be sending. It's one that doesn't need to be sent in order to bring this drug to market."
Some cardiologists think the reason the drug works so well for many African-Americans may not be a matter of "race" (for which there is no scientific/genetic basis), but is probably related instead to the root cause of their heart failure: African-Americans are more likely to suffer heart failure due to high blood pressure, while whites are more likely to suffer heart failure due to clots caused by heart attacks or atherosclerosis. But some African-American patients do suffer heart failure caused by clots or hardening of the arteries, and some white patients do have heart failure related to high blood pressure. So critics think that the drug should be labeled for use by patients with heart failure caused by hypertension, instead of use by African-American patients. Dr. Gail Christopher, co-chair of the National commission on Health, Genomics and Human Variation, says:
"It would be 'bad science' to label or market this drug as a 'Black' drug. More importantly, race-based claims are not credible in the face of modern genetic medicine."
The New York Times says:
"The drug's maker, NitroMed Inc., says its decision to test and market BiDil as a drug for African-Americans is based on solid science. But BiDil's application [for FDA approval] has engendered controversy, with many scientists convinced that race is too broad and ill-defined a category to be relevant in determining a drug's approval, especially since geneticists have failed to identify a biological divide separating one race from another. Scientists know that different people have different responses to medications, and in some cases these have been linked to race. The FDA, for example, has said that people of Asian ancestry are more likely than others to get serious side effects from the cholesterol-lowering drug Crestor. But research shows that the underlying genetic variations across races are small. [Studies have shown that genetic variation within any racial group exceeds that between two groups.] Scientists believe that genetic markers will someday be found that explain the different reactions to drugs, but for now, race or ethnicity is an imprecise shortcut. By approving BiDil, the FDA would go well beyond where it has in the past in using race as a category to evaluate which patients respond to drugs."
Other doctors feel that failing to take race into account when treating patients is unacceptable. Dr. Jim Kennedy, a spokesman for the Royal College of GPs, told the Times:
"To close one's eyes to colour is tantamount to a neglect of clinical duties. As a practicing professional, I took an oath not to pay any attention to a patient's race, creed, colour or background, and I take this very seriously. But if there is real evidence that because of your genetic inheritance you should be offered a certain drug, I would be negligent in not offering it to you. There may be people of African descent who will benefit from ACE inhibitors, but trying to guess what genes someone has inherited in impossible. So doctors make a reasonable stab at a first-choice drug and if it doesn't work we'll use our second choice. I think it's far worse if, for reasons of political correctness, we chose to ignore real, hard scientific facts."
What do you think about the prospect of race-based medicine? Should drug companies be marketing to specific ethnic groups? How is this harmful or helpful?
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