Columbia University Health Sciences researchers have developed a measurement that may solve the problem of diagnosing diastolic heart failure.
Heart failure, a slowly progressing disease that impairs the heart's ability to pump blood, affects more than 5 million Americans. Standard heart failure diagnosis relies on measuring ejection fraction, the ratio of the blood the heart pumps vs. how much blood the heart holds. An abnormal heart has an ejection fraction of 45 percent or lower. This type of heart failure is termed systolic.
But more than 2.5 million people with heart failure symptoms have diastolic heart failure, a condition where the heart still ejects more than 55 percent of its blood but holds less blood than a healthy heart. Yet no diagnostic test exists to confirm the problem.
Now Columbia investigators led by Dr. Mathew Maurer, Warner Lambert Assistant Professor of Medicine and director of the Clinical Cardiovascular Research Laboratory at the Allen Pavilion of NewYork-Presbyterian Hospital, have developed a new, non-invasive way to confirm diastolic heart failure. The research was published in the July 17 Journal of the American College of Cardiology.
The technique relies on a 3-D echocardiograph that takes a series of cross-sectional pictures, allowing researchers to construct a clear image of the heart. The researchers used the image to compare the amount of blood the heart pumps to the amount of heart muscle, a ratio they termed the myocardial contraction fraction.
In the study, the myocardial contraction fraction clearly distinguished among three groups of 140 adults: athletes, healthy sedentary adults, and adults with diastolic heart failure. The athletes averaged 50 percent, the sedentary averaged 40 percent, and the diastolic heart failure patients averaged 30 percent.
"Researchers have long been interested in studying diastolic heart failure but have not had an objective test that would help them confirm the diagnosis," Dr. Maurer says. "We feel strongly that this may be the test."
Hospital accreditation standards now require hospitals to better monitor and treat patients' pain. Most institutions use a single numerical scale that rates pain intensity from 1 to 10, but new Columbia University Health Sciences research suggests six different scales may be better.
Emotional factors affect pain that make interpretation of a single score difficult, says Dr. Crawford Clark, professor of medical psychology in the Department of Psychiatry at P&S. To identify factors that influence a patient's pain score, he led a study with colleagues from New York and Hong Kong in which they administered a pain questionnaire to 69 post-operative colon surgery patients. The 101 items in the questionnaire measured both physical sensations and emotions. The patients also rated their pain on the standard 1-to-10-numerical scale, with 10 defined as "pain as bad as it could be."
When the researchers compared scores on the pain questionnaire to the single number from the numerical pain intensity scale, they found the single pain scale number did not actually measure physical sensations of pain. Instead, it reflected unpleasant emotions, such as anxiety and fear.
The results, which were published in the August issue of the journal Pain, imply that a single pain rating is not sufficient to assess a patient's physical pain, the researchers say. Instead, based on the items in their questionnaire, they recommend a survey that measures six aspects of discomfort: pain sensation, anxiety, anger, depression, fear, and interference with physical activities. More research, though, needs to be done to determine whether the six scales will differentiate between the psychological and physical aspects of illness and allow for better treatment of a patient's condition.
"Clinicians generally assume a higher pain rating means the patient should get more pain medication," Dr. Clark says. "But if a patient is very anxious, he may be better treated with anti-anxiety drugs, reducing his need for morphine and, consequently, reducing the length of his hospital stay."
The human genome is filled with the DNA remnants of active and inactive "jumping genes," or retrotransposons, short DNA sequences that can insert copies of themselves anywhere in our 46 chromosomes, including in our genes.
Now new research, which was made possible by the human genome sequence, has found the jumping rate of L1 retrotransposons increased since the time humans and chimpanzees diverged, about 5 million years ago. The increase may help explain why humans and chimpanzees are so different even though their genes differ by only 1 percent. The researchwhich was led by Dr. Gary Swergold, assistant professor of medicinewas published in the August 6 Proceedings of the National Academy of Sciences.
L1 retrotransposons make up nearly 20 percent of the human genome, though only one group of 30 to 60 sequences are still actively copying and pasting themselves throughout the genome. Over time, a retrotransposon accumulates enough mutations to make it inactive. Remaining active retrotransposons continue to jump and evolve, creating different but related groups. Usually only one or a few groups are active at a time.
Dr. Swergold used the sequence of the currently active L1 retrotransposons and databases of the human genome sequence to find older, related retrotransposons that are now inactive. The relative ages of L1 groups were determined by comparing the sequences of members of a group. The number of base pair differences among the members of an inactive group indicates how long ago the group was active. After dating all the retrotransposons, he found that the number of active retrotransposons increased between 2 million and 10 million years ago. The upward trend reverses a decline in activity that began 50 million years ago.
"We don't know right now why retrotransposons have become more active," Dr. Swergold says, "but it could be that these elements are responsible for rapid evolutionary changes and contributed to the divergence of humans from chimpanzees."