Can Hormone Therapy or the Pill Prevent Brain Aneurysms?

Taking birth control pills or hormone replacement therapy could protect women against brain aneurysms later in life, a new study suggests, although one neurologist questioned the quality of the research. Cerebral aneurysms occur when a blood vessel in the brain weakens and balloons out, potentially leading to a hemorrhagic (or bleeding) stroke if the vessel bursts. These types of aneurysms are more common in women than men, possibly because lower levels of female hormones after menopause play a role in their development, the study authors noted.

Brain aneurysms are more common after the age of 40 and are most likely to burst when people are in their 50s. In the study, Dr. Michael Chen, of Rush University Medical Center, and colleagues interviewed 60 women who had experienced brain aneurysms and asked about their use of birth control pills and hormone replacement therapy, and compared their answers to those from a group of almost 4,700 other women in the general U.S. public. The women who had brain aneurysms were significantly less likely to have taken birth control pills or received hormone replacement therapy, and were also more likely to have entered menopause earlier, according to the report published online May 4 in the Journal of NeuroInterventional Surgery.

Previous research has suggested that taking birth control pills lowers the risk of hemorrhagic (bleeding) stroke in later life. However, women who either begin menstruating at an early age, don't have children, or both, face a higher risk. Because estrogen is important for the repair and maintenance of blood vessel walls, a drop in the levels of the female hormone is believed to be the reason for the increased risk to the structure of these vessels, the study authors noted in background information about the research. However, commenting on the study, neurologist Dr. Cathy Sila said the research is flawed and its conclusions overstated.

Selengkapnya →

New Clues to How Gastric Bypass Surgery Combats Diabetes

Gastric bypass surgery has been known to improve blood sugar control, often sending people with type 2 diabetes into remission, but experts have long wondered exactly how that happens. Now, a new study provides some clues. Circulating amino acids linked with insulin resistance decline dramatically in those who have the bypass surgery, the researchers discovered. They compared 10 obese people with diabetes who had the surgery with 11 who lost weight through dieting. "Something happens after gastric bypass that does not happen as much after the diet-induced weight loss," said Dr. Blandine Laferrere, an associate professor of medicine at St. Luke's Roosevelt Hospital Center and Columbia University, both in New York City.

The surgery, which reduces the stomach to the size of a small pouch, also modifies the junction between the stomach and small intestine. It leads to a dramatic reduction in the level of circulating amino acids that have been linked with diabetes. "The fact that gastric bypass results in the remission of diabetes in the majority of patients is not new," said Laferrere. According to background information in the study, 50 percent to 80 percent of diabetes cases go into remission after the surgery. What doctors have been trying to figure out, she said, is why the bypass surgery is so good at making the diabetes disappear. "The diabetes improves almost immediately, before a significant amount of weight loss occurs," she said. "That points out it is something other than the weight loss."

In the new study, the researchers evaluated biochemical compounds involved in metabolic reactions in the participants. Each group had lost about 20 pounds. The investigators found that the bypass patients had much lower levels of amino acids known as branched-chain amino acids, and the amino acids phenylalanine and tyrosine. "Those changes in the amino acids could be implicated in the mechanism of diabetes remission after gastric bypass," Laferrere said. Experts know the amino acids are linked with insulin resistance partly due to animal studies, she said. "If you supplement the diet of rats with branched-chain amino acids, you can induce more insulin resistance," she explained.

Selengkapnya →

Gene Therapy Against HIV Not a Proven Cure

Experts are reacting with cautious optimism to the announcement Monday that researchers reconfigured immune cells so that they became resistant to HIV in six patients infected with the virus. But they say the jury is out on whether the technique might ever spell an end to AIDS. The goal is ultimately a cure or what's called a "functional cure" having the body permanently keep HIV at bay but "we're not there yet," stressed Dr. Michael Kolber, professor of medicine and director of the Comprehensive AIDS Program at the University of Miami Miller School of Medicine.

The trial, reported Feb. 28 at a meeting of HIV specialists in Boston, "was a proof-of-principle that they could go in and do this. They demonstrated that the cells stayed in the patients, but the patients were not cured," said Kolber, who was not involved in the new research. Another expert agreed that the treatment's true potential remains uncertain. "If successful, this probably could have wide application, but going from six patients to an entire epidemic is a ways to go," said Dr. Michael Horberg, director of HIV/AIDS at Kaiser Permanente Health Plan and vice chair of the HIV Medicine Association.

"With other successes we've already had, that makes it more promising and people are starting to have a greater vision as to what's possible." However, as Kolber pointed out, this trial was what's known as a phase I trial, which means it was primarily looking at safety, not effectiveness, although investigators do often report on initial effectiveness results at this stage. The idea came from an isolated case that first made headlines in 2009, involving the so-called "Berlin patient." This man, an American AIDS patient living in Germany, was apparently cured after receiving blood cells from a donor who happened to have a rare, natural immunity to HIV.

Selengkapnya →

Few Stroke Patients Given Clot-Buster Quickly Enough: Study

Few eligible stroke patients get an injectable clot-busting drug within the recommended 60-minute window after their hospital arrival, new research finds. "It has been widely recommended that the 'door-to-needle' time should be 60 minutes," said study author Dr. Gregg C. Fonarow, a professor of cardiovascular medicine at the University of California Los Angeles David Geffen School of Medicine. The phrase refers to the timeframe between when the patient arrives at the hospital and when that patient is given the clot-buster, known as tissue plasminogen activator (tPA).

In his analysis of stroke patients from 1,083 hospitals, he found the 60-minute window was not the typical reality. "That occurs only in 26.6 percent of patients," he said. Fonarow was slated to present the findings Thursday at the American Stroke Association's International Stroke Conference in Los Angeles; the research is being published simultaneously in the journal Circulation. Perhaps even more surprising, the hospitals in the study were all participating in the American Heart Association/American Stroke Association's Get with The Guidelines-Stroke quality improvement program, which recommends early tPA administration.

"It involved some of the largest, best-known hospitals for stroke care," Fonarow said. The study looked at more than 25,500 patients who had suffered ischemic stroke in which a blood clot obstructs blood flow and had been treated with tPA within three hours of the start of symptoms. Just 6,790 got the intravenous drug within 60 minutes. During the course of the study, there was only modest improvement in the hospitals' track records.

Selengkapnya →

Lead Exposure May Raise Blood Pressure in Pregnancy

In pregnant women, even small amounts of lead in the blood may cause significantly higher blood pressure, new research suggests. The study of 285 pregnant women found that about one in four had a lead level higher than about 1 microgram per deciliter (1 mcg/dL) of umbilical cord blood. That's significantly lower than the safety thresholds set by the U.S Centers for Disease Control and Prevention, which recommends taking action to reduce lead exposure when pregnant women or children have a blood lead level of 5 mcg/dL.

Even so, women in the study with lead levels greater than 1 mcg/dL had higher systolic and diastolic blood pressure readings than those with lower lead levels. The average increase was 6.9 mm Hg and 4.4 mm Hg, respectively. Though further research is needed, the findings suggest that pregnant women may be as sensitive to lead toxicity as young children, said the researchers. Prolonged high blood pressure during pregnancy can lead to complications such as preeclampsia or eclampsia, potentially deadly seizures that also can increase a woman's future risk of heart attack.

"We didn't expect to see effects at such low levels of lead exposure, but in fact we found a strong effect," Dr. Lynn Goldman, dean of the George Washington University School of Public Health and Health Services, said in a university news release. The study did not find an association, however, between lead exposure and pregnancy-induced hypertension or preeclampsia.

Selengkapnya →

Docs Claim Transplant Cured Man of HIV, But Experts Urge Caution

In a rare case, a man living in Germany who had both leukemia and AIDS no longer has any detectable HIV cells in his blood following a stem cell transplant for his leukemia three years ago. But experts were quick to caution that the case does not have practical implications for the treatment of AIDS worldwide. As it turns out, the donor for that transplant carried a rare mutation in a gene that increases immunity against the most common form of HIV.

First reported in 2009, this follow-up study, published online in the journal Blood, confirms that the recipient patient is still free of both leukemia and HIV three years after the transplant. But one expert issued strong words of caution in interpreting the finding. "Our phones have been ringing off the hook," said Dr. Margaret Fischl, director of the AIDS clinical research unit at the University of Miami Miller School of Medicine. "We are having patients calling us and asking if they can stop their antiretroviral therapy and the answer is uncategorically no."

The theory is that if you could wipe out every infected cell you could cure HIV, Fischl said, but this is a unique case. The patient had intense chemotherapy and radiation, then relapsed and was given a second transplant from the same donor. The donor was unique in that he had a gene that could fight the most common form of HIV. This mutation is seen in about one in every million people, Fischl explained.

Selengkapnya →