What's Hot Archive
December 30, 1999
Ginkgo Helps with Intermittent Claudication
A German study found high doses of the herbal dietary supplement ginkgo biloba extract improved ambulation and limited pain when walking in sufferers with intermittent claudication, a disease caused by obstructions to blood flow in the arteries that supply oxygen to the legs. Pain can become severe with exercise or ambulation.
In Germany, Ginkgo biloba extract is a licensed treatment for peripheral arterial circulatory disturbances such as intermittent claudication, as well as cerebral dysfunction. The standard dose to treat problems involving peripheral circulation is 120 mg to 160 mg. Researchers tested the ability of 74 patients to walk pain free after administering a higher dose, which is often recommended for cerebral problems, early Alzheimer's disease, depression and impotence.
At the study's start, participants could walk about 100 meters on the treadmill under standardized conditions. After 24 weeks, 36 people talking 240 mg ginkgo biloba extract per day could walk more than twice as far without pain. The 38 participants receiving the standard dose of 120 mg daily were able to walk 60 additional meters. Researchers said both dosages proved safe and were well tolerated by patients.
Europeans use herbal remedies more often than Americans. According to a U.S. National Institutes for Health report, more than 5 million prescriptions are written annually in Germany for ginkgo biloba extract. Chinese practitioners began using ginkgo biloba more than 2,800 years ago. The herbal remedy improves circulation and mental function. It removes free radicals in the vascular system and interferes with clot formation. Studies have also found it helpful in relieving stress, saying ginkgo biloba may decrease the release of excess cortisol.
December 30, 1999
Vitamin C Reduces High Blood Pressure
A daily dose of vitamin C can lower high blood pressure in patients with hypertension. In a National Institutes of Health-sponsored study, researchers at two medical centers worked with 45 patients, whose diastolic blood pressure was above 90 mm Hg and systolic more than 140 mm Hg. The patients differed in age, sex, race and smoking status. Subjects and doctors did not know which patients received the vitamin C and which received an inactive ingredient. Doctors excluded anyone with more serious health conditions, such as diabetes or coronary artery disease.
After taking 500 mg of vitamin C daily for one month, patients' systolic, diastolic and mean blood pressures declined approximately 9 percent. "We believe this is a significant finding that may be of considerable value to patients who have moderately elevated blood pressure," said Professor Balz Frei, director of the Linus Pauling Institute at Oregon State University. "Working with their doctors, it may provide a way to bring their blood pressure back within acceptable levels without the cost or possible side effects of prescription drugs."
The 500 mg dose does not cause side effects, is inexpensive and offers other health benefits. Frei said patients could partially obtain the vitamin from a diet rich in fruits and vegetables. He cautions that patients with more serious blood pressure elevations still need to follow their physicians' advice about prescription medications and lifestyle changes.
Scientists are uncertain about the vitamin's mechanism of action, but based on previous research believe its antioxidant properties aid in relaxing blood vessels, thus lowering blood pressure. Studies last year showed the same dose of vitamin C helped prevent chest pain in patients with angina pectoris, and decreased heart attack and stroke risk. Vitamin C does not lower blood pressure in people with normal readings.
December 30, 1999
Methotrexate Can Cut Arthritis Mortality Risk
An established treatment for rheumatoid arthritis, methotrexate has been prescribed for years without doctors or patients knowing if it really improved long-term outcomes. New research found the drug reduced the rate of death from the disease's complications by up to 50 percent. Rheumatoid arthritis causes joint pain, stiffness and swelling in multiple joints. The disease frequently strikes early in life and leaves patients with a shorter expected life span in its severe form.
Researchers at the University of Kansas reviewed records for 1,842 patients during a 25 year period. They found that patients taking methotrexate alone had half the mortality rate of the average patient. Those taking methotrexate with other drugs had a 39 percent reduction in mortality risk. Prednisone, another drug frequently used to treat rheumatoid arthritis, presented an increased risk. "This demonstrates that methotrexate does, in fact, alter the course of rheumatoid arthritis," said lead investigator Frederick Wolfe, MD, of Witchita, Kansas.
Methotrexate can produce severe side effects including possible fatalities, so patients using the drug should be closely monitored by a knowledgeable physician. But for those with disabling rheumatoid arthritis, the drug may prove to be a lifesaver.
December 23, 1999
Genetically Engineered Mice Help in Testing for Mad Cow Disease
While studying the relationship between bovine spongiform encephalopathy (BSE) or mad cow disease, and a new variant of Creutzfeldt-Jakob disease (nvCJD), researchers have developed genetically engineered mice to test for prions that cause the conditions. Prior to the new test, the only proven method of determining whether a cow had the disease was to wait out the four year incubation period.
Researchers at the University of California San Francisco Institute for Neurodegenerative Diseases said developing a means of assessing risk to humans and more sensitive methods of detection are critically important and urgently needed, considering the high number of infected cows in Great Britain. They said that current screening techniques are not adequate.
Scientists developed the genetically engineered mice to prove that prion proteins causing the new variation of the fatal, brain-degenerative nvCJD are the same as those that cause the bovine disorder. After approxinately 250 days, researchers saw identical reactions and patterns of brain damage in mice injected with BSE prions as in mice injected with brain tissue from Scottish patients suffering from nvCJD. The researchers also tested sheep prions on the mice, which produced dramatically different results. "The fact that the human new-variant CJD prions so precisely duplicate the properties of native bovine BSE prions in their behavior on transmission to the transgenic mice creates a compelling argument for a persuasive link between BSE and nvCJD," said lead author Michael R. Scott, Ph.D.
There have been no cases of mad cow disease found in U.S. cattle and no Americans have developed the new variant CJD. However, the disease incubates in humans for 10 years before symptoms appear.
December 23, 1999
Benign Breast Disease is Cancer Risk for Some Women
A study found some women with nonmalignant breast disease at increased risk of breast cancer due to their inability to detect signals that stop rapid cell reproduction.
Normally, a growth factor tells mammary cells not to divide. Cells pick up the message through a receptor. Researchers at the Vanderbilt-Ingram Cancer Center discovered that when fewer active receptors are available, women with a common, benign overgrowth of normal cells, called hyperplasia, were more likely to develop invasive breast cancer. "This is the first time we've found credible evidence of a biologic marker of increased breast cancer risk in women with unequivocally benign breast disease," said William Dupont, Ph.D., professor of Preventive Medicine at Vanderbilt.
The research involved nearly 10,000 women whose biopsies revealed benign breast disease during a thirty year period. Scientists compared tissue samples from women who later developed breast cancer with those of similarly-aged subjects from the same time period who did not. Then they tested the tissue for the presence of the receptor. "We have found that there are different types of benign breast disease with different levels of risk," Dupont said. "Most women who have undergone benign breast biopsy, about 70 percent, have nonproliferative disease that's not associated with any elevation in risk."
However, the study found about four percent of women are four to five times more likely to develop cancer, and the rest had a mildly increased risk. In the future, a laboratory test might be able to determine levels of this receptor. Doctors and genetic risk counselors could use the information to reassure women who are not at risk, or guide decisions about additional screening, such as whether to have regular mammograms starting at an earlier age, for those with a moderately increased risk. The findings also could help physicians develop new prevention techniques.
December 21, 1999
Hypericum Extract Improves Quality of Life
A German clinical trial proved hypericum extract, derived from the herb St. John's Wort, effective in the treatment of depression and improved patients' quality of life.
During an eight week double-blind trial, 263 moderately depressed men and women were given either 350 mg hypericum extract three times a day, 100 mg of imipramine or a pill without an active ingredient. Patients receiving the herbal extract showed improvement on multiple standardized mental health tests after four, six and eight weeks. At the end of eight weeks, hypericum and imipramine both proved effective in the treatment of depression and enhanced mental health, but only the herbal extract improved physical well being. Patients tolerated the extract better than the prescription medication, with the rate of adverse events consistent with those taking the placebo. Scientists said the lower rate of side effects could improve patient compliance with a mood-altering medication regimen.
Researchers concluded that hypericum extract is a safe and effective depression treatment that also improves quality of life and offers promise as a long-term therapy. They felt the herbal remedy should be considered as an alternative first choice treatment for mild to moderate depression.
Two German studies, reported earlier this year, found similar effectiveness with hypericum. However, one said patients over 65 years of age responded somewhat slower than younger subjects. German Health Authorities have recognized hypericum extract's effectiveness in the treatment of depression since 1984, saying the herbal remedy appears to have a mechanism of action similar to, but not as strong as, selective serotonin reuptake inhibitors, which are available only by prescription. Prozac and Zoloft are examples of selective serotonin reuptake inhibitors.
December 20, 1999
High Blood Pressure Could Cause Cognitive Decline
French researchers found people with high blood pressure more likely to experience a decline in ability to think, remember and learn. The study showed those with untreated hypertension at greatest risk.
Scientists measured the blood pressures and mental abilities of more than a thousand randomly selected people between 59 and 71 years of age. At the start of the research, 167 people suffered from high blood pressure, systolic readings equal or greater than 160 mm Hg or diastolic equal or above 95 mm Hg. About half of those with the condition took antihypertensive medication to control it. At the end of the four year study, 21.7 percent of participants with untreated hypertension developed a severe cognitive decline, defined as a drop of four or more points on a standard mental status test. The lead scientist said people experiencing such severe declines are most likely to develop Alzheimer's disease or other dementias.
Just over seven percent of those with normal blood pressure experienced a severe decline in abilities to think, remember and learn; and 7.8 percent of subjects with treated hypertension experienced a similar decrease in cognitive abilities. "If high blood pressure and other vascular factors play a role in dementia, then it might be possible to prevent or delay the occurrence of this dreadful disease by controlling high blood pressure and other vascular factors," said study author Dr. Christophe Tzourio, a Paris neurologist.
Although more research is needed to determine the degree of dementia risk caused by hypertension, Tzourio said this study proved high blood pressure may adversely alter mental ability. "People with high blood pressure should be encouraged to get it under control in order to avoid this harmful effect," he said. "People who don't know their blood pressure status should see their doctor to get it checked."
December 17, 1999
New Method Charts Cardiac Aging As It Occurs
A study at the University of Queensland and the Prince Charles Hospital in Brisbane, Australia is monitoring in a rat model cardiovascular aging changes as they occur and studying the effects of different drugs on the cardiovascular system. The aim is to point the way to a longer, healthier life and also to develop better heart drugs.
Dr Lindsay Brown, University of Queensland senior lecturer in physiology and pharmacology, and Dr Darryl Burstow and Ms Kathy Wilson from the Prince Charles Hospital, are using echocardiography to obtain serial measurements of cardiac function.
Although echocardiography has been available for a long time, it has not until now been possible to use it in the animal model, because the rat heart is much smaller than a human heart, with a heart rate 4-5 times faster that of humans. Dr Brown is using a neonatal transducer, one designed for analyzing human heart function in utero.
The rats are being studied from very young adulthood to old age (24 months) to determine what is happening in their hearts, since cardiovascular disease is basically a disease of the elderly and changes occur in heart function with aging.
"We need to know whether this model mimics the human disease state and then whether these aging changes can be reversed using different drugs. Also we need to know not just whether we can help them live longer but also whether they are living better. It is no use living longer if there is no quality of life."
Another arm of this research is examining the effect of an "old" drug, spironolactone, which can prevent the heart from becoming stiff in heart failure. A large study with more than 1000 patients published in September shows that administration of this drug improves survival of heart failure patients by 30%. Dr Brown and his coresearchers are hoping to find evidence that a variety of drugs will prevent aging changes in the heart and blood vessels and also return function to normal. This will then allow human trials to proceed.
Dr Brown and his colleagues presented an initial study of hypertension in rats to the Cardiac Society meeting in Wellington in August, showing that it was possible to inhibit the cause of hypertension and reverse the increase in blood pressure by adding an antagonist called candesartan. "Not only does this bring the blood pressure down, it also reduces the wall thickness of the heart chambers - which was increased by the hypertension. Using echocardiography, we were able to see evidence that function was returned to normal by means of the drug treatment. So echocardiography makes it possible to evaluate different drug treatments and ensure that cardiac function is returned to normal."
December 15, 1999
Large Study Confirms Lowering Cardiac Risk Factors Increases Life Expectancy
A national study found people could add from 5 to 9.5 years to their lives by maintaining a low risk cardiac profile. Researchers measured long-term mortality rates of more then 366,000 participants and found that nonsmokers with cholesterol levels less than 200 mg/dL and blood pressure readings under 120/80 had significantly less heart disease and fewer deaths than their counterparts. The study excluded people with a history of diabetes or heart attack. Although previous reports have supported the risk factor theory with estimated statistics, these studies were too small for accurate measurement.
Clinicians calculated the new information using results from two long-term studies, one conducted over a 22-year period. Only five to ten percent of the subjects qualified as low risk. Among all age groups, deaths attributed to heart disease comprised only six to eight percent of all deaths among those at low risk, compared to 25 to 29 percent in the other subjects.
In the low risk population, deaths from heart disease were 77 to 92 percent less, deaths from stroke 52 to 76 percent less, and deaths from all causes 50 to 58 percent less for men and 40 percent less for women.
"A nearly 80 percent lower rate of coronary heart disease deaths among low risk middle aged adults compared with those of average risk is an astounding difference in the rates of heart and cardiovascular disease," said Dr. Claude Lenfant, director of the National Heart, Lung, and Blood Institute. "Unfortunately, only a small percent of adults is at low risk. Our challenge for the 21st century is to prevent risk factors from developing in the first place by encouraging healthy behaviors early in life."
Researchers said increasing the number of people at low risk could aid in ending the heart-disease epidemic.
The findings were reported in the Journal of the American Medical Association.
December 14, 1999
Green Tea Could Aid Weight Loss
Known for its heart protective properties, green tea extract now has been proven helpful as a weight loss aid. The tea raises metabolic rates and speeds fat oxidation. Researchers at the University of Geneva, Switzerland attribute the effect to the tea's catechin polyphenols, which increase the rate the body burns calories, and a synergistic relationship between the ingredients in green tea.
Lean to mildly overweight male subjects were randomly separated into three groups, receiving with meals the green tea extract, containing 50 mg of caffeine and 90 mg of epigallocatechin gallate; 50 mg of caffeine, or a placebo. The men ate a typical American diet, averaging 40 percent fat. The daily dose of caffeine, 150 mg, equaled about one cup of brewed coffee.
Subjects spent 24 hours in a respiratory chamber designed to measure the rate calories were burned and energy expenditure. Those receiving the green tea experienced what researchers consider a significant increase in both tests. Tea extract subjects burned 4 percent more calories, and overall energy expenditure rose 4.5 percent.
Although previous studies had determined that caffeine could increase metabolic rates at higher doses, the results of this trial could not be attributed to caffeine, since the subjects receiving only caffeine, in an amount equal to that found in green tea, experienced no change in energy expenditure or calorie burning. In addition, researchers said green tea appears safer than high doses of caffeine for obese patients (who may have high blood pressure or other heart problems) because it does not increase heart rate.
In another recently reported Japanese study, research supported by the National Cancer Institute found green tea inhibited cancer cell growth. Breast cancer patients consuming more than five cups daily remained disease free longer and experienced a lower recurrence rate than patients consuming fewer than four cups daily.
December 7, 1999
Family Bonds Can Prolong Life
Strong emotional ties with grown children can add years to an older adult's life, according to findings of a thirteen year study conducted by scientists at the University of Southern California. Researchers discovered parents sharing a close, loving relationship with adult children were 40 percent less likely to die.
"We started examining both emotional and physical care," said Haitao Wang, PhD, with USC's Ethel Percy Andrus Gerontology Center. "Even after we controlled for physical care, the emotional ties had significant effect."
Wang estimates maintaining a close relationship with the younger generation could add four or five years to a person's life. Research continues into reasons family bonds decrease mortality. "We're looking at two major pathways," Wang continued. "One is depression. If someone suffers from depression, they are more likely to die, and if they have strong emotional ties, they have less depression."
But mood does not completely explain the results. "There are other mechanisms going on," Wang said.
Wang also is evaluating practical support, such as rides to the grocery or household chores, and whether children with close ties provide more assistance if a parent becomes disabled. Older adults receiving practical help from their children were 20 percent less likely to die than those not obtaining assistance. After taking practical support into consideration, the results remain favorable for feelings of love and closeness.
"When we control for these factors, affection is still there," Wang said. "We're trying to figure it out."
The research is part of a larger, long-term study looking at intergenerational relationships, how dynamics change over time and how changing roles alter well-being. The dramatic mortality results were based on interviews and health and death records of 220 adults, who were between 60 and 90 years of age at the start of the study.
December 6, 1999
Work Stress Found to Alter Blood Clotting and Increase Heart Disease
Doctors recognized a while back that people who approach work as a "must win" race seem to develop heart disease more readily than their laid back counterparts, but the physical reasons have eluded scientists. Researchers in the Netherlands now think they can explain one reason why work stress increases the risk of heart disease. The team discovered people feeling overly committed to work or exhibiting an exhaustive coping style had decreased natural clot-dissolving ability. The body's clot dissolving mechanisms work closely with clot-forming systems to maintain equilibrium. An imbalance could trigger excessive coagulation, subsequent atherosclerosis and cardiovascular disease.
"Individuals who score high on over commitment are competitive, impatient, have a high need for approval, and are unable to 'let go,'" said study co-author Tanja G. M. Vrijkotte, MSc. "In the long run, they are at risk for feelings of exhaustion and psychological breakdown."
The study found that the overly committed workers were also prone to cardiovascular disease. Researchers questioned 124 middle-aged white collar workers about their perceived work stress, efforts, rewards, degree of commitment and coping styles. Previous studies have found chronic work stress associated with demanding jobs that offer minimal compensation. Scientists also tested the participants' blood several times during the work week. The blood tests uncovered the impaired natural clot-dissolving ability.
More research is needed to determine benefits of treatment or therapy to manage stress, according to the American Heart Association. However, the organization also reports that psychosocial therapies designed to prevent second heart attacks show promise.
December 3, 1999
Depression Limits Activity and Immune Function
Researchers have discovered a link between mild to moderate depression and impaired immune function which they attribute to lower levels of physical activity among the depressed. The scientists at Carnegie-Mellon University and the University of Pittsburgh School of Medicine believe the brain-behavior connection could explain higher rates of sickness and death in depressed people.
The study found a 42 to 63 percent difference in specific immune functions related to activity levels between depressed and nondepressed participants. The conclusions, presented in Psychosomatic Medicine, offers the first published data identifying a behavior as the cause of immune system changes found in depressed women. Researchers measured immune function in 64 women, half nonhospitalized and depressed, the other half healthy. They also tested immune response compared to levels of multiple hormones, but said neuroendocrine differences could not account for the disparity in immune function.
Although scientists evaluated the effects of health practices often associated with depression - including alcohol, tobacco and caffeine use, nutrition, and sleep quality - physical activity was the only component that could explain the impaired immune function in depressed women. "An important next step of this research is to determine whether interventions aimed at increasing physical activity can buffer people from the immunologic changes associated with depression," said Gregory E. Miller, PhD, lead author of the study.
December 3, 1999
Type of Calcium Supplement Makes a Difference
Three recent studies conducted at the University of Texas found calcium citrate was successful in preventing bone density loss and was better absorbed than calcium carbonate.
During the first study, scientists analyzed data from 15 previously published randomized trials, determining bioavailability, or how much calcium the body absorbed from the two over the counter supplements. They found calcium citrate 22 to 27 percent better absorbed than calcium carbonate, whether taken on a full or empty stomach. Doctors conducting the second study measured peak and cumulative increases in blood calcium concentration. Tests, conducted over six hours following a single oral dose, found that calcium citrate was absorbed faster and in greater quantity than calcium carbonate.
"Our results show that even under the most favorable conditions, calcium carbonate is not nearly as well-absorbed as calcium citrate," said Dr. Howard Heller, assistant professor of internal medicine. "We were surprised at the magnitude of the difference in absorption rates - with calcium citrate being absorbed two and a half times better than calcium carbonate."
A third study proved that calcium citrate stabilized bone loss in early post-menopausal women. During a two year period, 63 women, who were five to 10 years into menopause, took 800 milligrams of calcium citrate or a placebo. Bone loss stabilized in the bones of the spine, thigh and forearm in the group taking the calcium. Women not taking the calcium experienced significant decreases in the bone density of spinal and forearm bones, but no change in the thigh bone. The physicians consider calcium citrate, used alone, an effective treatment in preventing skeletal bone loss and osteoporosis in early post-menopausal women.
About 18 million Americans experience decreases in bone density due to a lack of calcium in the bones. Another 10 million suffer from osteoporosis, or brittle-bone disease.
December 2, 1999
Gingko Extract Improves Memory and Information Processing
Psychological testing in Melbourne, Australia of people using the herbal extract, Ginkgo biloba for 30 days, has found significant improvements in working memory and in the speed of the brain's information processing. The tests involving 55 participants aged between 18 and 40, were conducted by researchers at the Brain Sciences Institute (BSI), Swinburne University of Technology.
Gingko biloba comes from the gingko or maidenhair tree, a tree that has existed on the planet for 260 million years and which is widely used in the United States and Europe to increase blood circulation, as an antioxidant and as an agent that may ameliorate cognitive decline. The BSI tests also showed that participants with average IQs who took Gingko biloba improved significantly more than those with a higher IQs in tests of attention and problem solving. In fact the scores of those with a lower IQs in tests of attention increased nearly to the level of performance of the higher IQ group.
All participants were tested on a battery of psychological tasks assessing intelligence, concentration, attention, memory, problem solving, speed of visual information processing, and social intelligence before and after consuming their respective tablets. They were tested in two groups, one taking the Ginkgo biloba extract and the other a placebo.
Dr Con Stough, associate professor in Cognitive Neuroscience at the BSI, said that the tests indicated that Gingko biloba was the first "smart pill" validated by scientific empirical research. "The results suggest that in healthy young people, Gingko biloba extract administered for 30 days significantly boosted a range of intellectual variables," he said.
"However these results should be treated with some degree of caution until they are replicated in independent laboratories. Trials should also be conducted assessing cognitive changes, that is people's ability to comprehend or understand, due to Ginkgo biloba extract administration over a longer period of time. The results may help us further understand from a scientific point of view cognitive changes as we get older and the pharmacological properties underlying aging."
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