What's Hot Archive
October 30, 2000
Lipoprotein-associated phospholipase A2 strong predictor of heart disease
Lipoprotein-associated phospholipase A2 is an enzyme that accompanies low density lipoprotein (LDL), or "bad" cholesterol in the blood, and may be involved in modifying LDL. Also known as platelet-activating factor acetylhydrolase, the expression of this enzyme is regulated by mediators of inflammation. While other inflammatory markers are known to be predictive of coronary events, this ability is modified by other risk factors.
This study utilized stored biological samples from The West of Scotland Coronary Prevention Study, a trial that evaluated the drug Pravastatin's preventive ability against coronary events in 6,595 men. Researchers analyzed the study's baseline samples for lipoprotein-associated phospholipase A2, as well as other markers of inflammation, such as C-reactive protein, fibrinogen and white cell count in 580 subjects who went on to develop a coronary event (defined in this study as a myocardial infarction, bypass surgery or angioplasty) and matched each of these for smoking status and age with controls who did not later experience a coronary event.
The study found that inflammatory markers were predictors of coronary events but their predictive ability was weakened when other risk factors, such as body mass index, HDL levels, triglycerides and systolic blood pressure were taken into consideration. Lipoprotein-associated phospholipase A2, however was strongly associated with the risk of a coronary event, a risk that is statistically independent of other factors. The group that had the highest levels of the enzyme also had double the risk of a coronary event than those who had the lowest levels.
The researchers proposed that lipoprotein-associated phospholipase A2 is placed to release products of LDL oxidation into the artery wall. Because inhibition of the enzyme has been demonstrated to have desirable effects in vitro, they predict that the enzyme will become a new therapeutic target.
October 27, 2000
Testosterone patch helps relieve angina
It has been widely believed that androgenic hormones such as testosterone are a contributor to heart disease due to the far greater number of men than women afflicted with the disease, and the fact that sudden cardiac death has been observed in some people taking high doses of anabolic steroids. However, it has recently been observed that androgenic hormones such as testosterone may benefit the heart, and it is interesting to note that cardiovascular disease usually appears later in a man's life, when testosterone levels are low.
In a study published in the October 17, 2000 issue of Circulation, Journal of the American Heart Association, forty-six men with stable angina received two 2.5 mg transdermal testosterone patchs to be applied nightly for two weeks, and were then randomized into a group receiving either the testosterone patches or a placebo for twelve weeks. The men were tested on a treadmill for their angina threshold via electrocardiogram findings that would indicate the onset of angina at the beginning of the study and at two, six, ten and fourteen weeks. Blood pressure, pulse, body mass index and serum testosterone were also calculated, as were other blood values.
At the study's onset, androgen levels were at the lower limit of the normal range for both the testosterone and the placebo group. After treatment with testosterone, those receiving the hormone had an increase in androgens without changes in other parameters. However, the amount of time that it took the men on testosterone to demonstrate the onset of angina when tested on a treadmill was significantly longer compared to the placebo group, and the men receiving the hormone reported less pain and less limitation from physical problems.
The authors note that the size of the study was small, and recommend large scale clinical trials to further study the effects of androgen replacement therapy in men.
October 25, 2000
Beta-carotene lowers risk of ischemic stroke
In a six year follow up of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study in Finland, researchers conducted a study of 26,497 male smokers without a history of stroke. The study, published in the October 2000 issue of the journal Stroke, published by the American Heart Association, sought to correlate the consumption of antioxidants with the risk of stroke type, broken down into either intracerebral hemorrhage, subarachnoid hemorrhage or cerebral infarction (ischemic stroke). The participants' diets were assessed at the beginning of the study with the use of self-administered questionnaires which asked the subjects to report the frequency of consumption and portion size of foods during the past year. Each subject's median intake was calculated for flavonols and flavones, vitamin C, vitamin E, beta-carotene, lutein, zeaxanthin, and lycopene. Although various of these nutrients appeared to be associated with a decreased risk of a particular type of stroke, when adjusted for the presence of other dietary antioxidants, their association lessened. Not so, however, for the consumption of beta-carotene, which remained a significant risk reduction factor against cerebral infarction even when adjusted.
Although vitamin E was not shown to be associated with a reduced risk of stroke in this study, neither was it associated with an increased risk of hemorrhagic stroke, a concern which has occasionally been voiced because of vitamin E's blood-thinning ability.
The study authors conclude that these results cannot be applied to nonsmokers, and that a protective association between vegetable and fruit consumption and stroke risk was confirmed.
October 23, 2000
Ingredient in cold and diet medications linked with stroke
Over the counter cold remedies and diet pills containing phenylpropanolamine may be a culprit in hemorrhagic stroke in women under fifty. Despite protest from manufacturers, experts from the Food and Drug Administration and Yale University believe a small risk may exist and are considering reclassifying medications containing the substance as prescription drugs. Hemorrhagic stroke occurs when a blood vessel in the brain ruptures, and is often fatal. Although rare in young people, Food and Drug Administration records show forty-four women with a median age of thirty-five having suffered from hemorrhagic stroke while using phenylpropanolamine. Of the 130 million Americans in the eighteen to forty-nine age group, 10,400 per year are afflicted with hemorrhagic stroke.
In a five year study at Yale University, 702 survivors of hemorrhagic stroke under fifty years old were compared to 1,376 control patients who had no history of the condition. It was discovered that phenylpropanolamine increases the risk of stroke in women within three days of taking the drug. The effect was not seen in men. Risk was dose dependent, with doses over 75 mg per day associated with the highest risk. The drug initially raises blood pressure in some people, which accounts for the higher incidence of stroke within the first few days of use. Manufacturers' claim that the study is flawed because the stroke patients may have had other risk factors.
Dr Walter Kernan, a medical professor at Yale University stated, "The message for women should be, PPA does appear associated with an increased risk of hemorrhagic stroke but it is not a huge risk."
October 19, 2000
African herb relieves arthritis pain
In a study published in a recent (volume 7 issue 3) of the journal Phytomedicine, French researchers tested the herb Harpagophytum procumbens, commonly known as devil's claw, on 122 osteoarthritis patients between the ages of 30 and 79. The study participants, who had arthritis of the knee and hip, over a four month period received either devil's claw or the drug diacerhein, which is approved in France and Italy. Both the herb and drug groups experienced similar pain relief benefits, but the group taking devil's claw experienced significantly decreased side effects, particularly less gastrointestinal distress.
Devil's claw has been aproved by the German Commission E as a nonprescription drug to treat pain and inflammation of the joints, termed degenerative disorders of the locomotor system. The herb comes from the Kalahari desert of Africa and is used in traditional African medicine.
"At least two previous clinical trials on devil's claw have supported its use as an aid in treating lower back pain and rheumatic conditions," commented Mark Blumenthal of the American Botanic Council, an independent nonprofit education and research organization. "This study is significant in that it is the first to show the potential benefits of devil's claw for osteoarthritis. Although more research is warranted, this may be good news to people who suffer from osteoarthritis, as well as their physicians, whose therapeutic choices have been fairly limited."
October 18, 2000 has been proclaimed National Menopause Day
Experts recommend calcium supplements for women
In a turnaround in the long-held belief that we can get all the nutrients we need from food, a recent survey of the conservative American Dietetic Association revealed that nine out of ten dieticians recommend supplements and fortified foods as a good way to obtain sufficient nutrients. At this week's Food and Nutrition Conference in Denver, sponsored by the American Dietetic Association, women's calcium needs will be one of the key issues. The survey reported that 98% of registered dieticians agree that getting enough calcium is an important nutritional concern for the women they counsel, and that 86% find energy levels to be another major concern.
ABC medical correspondent Nancy Snyderman MD, commented, "We all lead such busy lives that it can be very difficult for women to get the nutrients they need to help maintain energy now and good health down the road. Women should look for simple, convenient solutions, and supplements and fortified foods can help fill that bill. These are very serious issues. Even with all of the attention that's been paid to calcium over the last few years, many women still aren't getting the message - this could lead to an epidemic of osteoporosis as the Baby Boomers age."
Osteoporosis is a disease that is common in postmenopausal women in which bones become porous and brittle, predisposing them to fractures, particularly of the spine. In what is being called a calcium crisis, 75% of women over thirty-five are not receiving enough calcium, which will contribute to osteoporosis later in life. The hormone deficiciencies of menopause also play a primary role in the development of the disease.
October 16, 2000
Older oral contraceptives up breast cancer risk
In a study published in the October 11 issue of the Journal of the American Medical Association, researchers discovered that the use of oral contraceptives before 1975 significantly increased the risk of breast cancer in the sisters and daughters of 246 women diagnosed with breast cancer between 1944 and 1952. In an effort to determine if whether the association between the use of oral contraceptives and breast cancer is influenced by a family history of the disease, researchers conducted a telephone survey of 394 sister and daughters, 3002 granddaughters and nieces, and 2754 women who married into the families of the original 246 breast cancer patients. The 2754 women who were not genetically related were included to account for similar environmental exposures.
Sisters and daughters of the women diagnosed with breast cancer experienced a three times greater risk of breast cancer if they used oral contraceptives before 1975. These results were the same after adjustment for age at menarche, menopause and first birth, and whether one had smoked or had their ovaries removed. The researchers believe that the reason for this is the higher estrogen content of the older oral contraceptives that were in use at that time. This risk was not observed in non-first degree relatives.
The researchers conclude with the recommendation that first-degree relatives of breast cancer patients who have used oral contraceptives be particularly vigilant concerning breast cancer screening.
October 13, 2000
Carotenoids lower lung cancer risk
Lung cancer is responsible for a greater number of deaths than any other cancer in this country. The consumption of fruits and vegetables has been correlated with a lower incidence of lung cancer, which was believed to be due to their beta-carotene content, however some studies using beta-carotene supplements have not confirmed this. In a study published in the October 2000 issue of the American Journal of Clinical Nutrition, researchers utilized newly available data on the carotenoid breakdown of foods to determine which specific carotenoids had the greatest association with lowered lung cancer risk. Carotenoids are a family of nutritional compounds including alpha-carotene, beta-carotene, lycopene, lutein and beta-cryptoxanthin.
The researchers examined food frequency questionnaires completed by 77,283 women during the twelve year follow-up of the Nurses Health Study, and by 46,924 men from the Health Professionals Follow Up Study, which followed participants for ten years. Consumption of alpha-carotene and lycopene were found to be strongly associated with a lower lung cancer risk. Nonsmokers in the top group of alpha-carotene consumption experienced a 63% reduction in lung cancer incidence compared to the group with the lowest alpha-carotene intake. Beta-carotene, lutein and cryptoxanthin consumption were also mildly associated with lowered lung cancer risk, but were not determined significant. The researchers speculated that a four to eight year time period before the onset of lung cancer may be the crucial time for carotenoids ability to prevent cancer from developing, as this was where the strongest associations were observed.
The study's authors concluded that "overall intake of a diversity of carotenoid-rich foods is inversely related to lung cancer risk." (American Journal of Clinical Nutrition, vol 72, no 4)
October 11, 2000
Controlled amino acid treatment fights cancer
Acting upon the knowledge that cancer needs specific amino acids to be able to survive, the A P John Institute for Cancer Research has formulated what it calls Controlled Amino Acid Treatment, or CAAT, to aid in the battle against cancer. In a study conducted to confirm earlier research which indicated that amino acid deprivation may be of benefit in cancer, nineteen patients with inoperable or highly metastatic cancer of the breast, lung, colon, brain, pancreas, ovaries who were given six months to live by their physicians were given CAAT along with conventional therapy. Three of the patients were treated with CAAT only. CAAT consists of an amino acid supplement in which certain amino acids necessary for cancer growth are eliminated, a low calorie, low carbohydrate diet rich in omega-3 fatty acids, and supplementation with the following: N-acetylcysteine, tocotrienols, genistein, calcium D-glucarate, L-carnitine and coenzyme Q10, plus an antioxidant formula if their cancer was slow growing. Those with faster growing cancers were advised against antioxidant supplementation because of the concern that it might inhibit apoptosis (cell death). (Tocotrienols should be excluded in patients with non-Hodgkin's lymphoma.)
All nineteen patients outlived their estimated remaining six months, and sixteen are still alive an average of four years later, with fifteen experiencing a reduction in tumor size or elimination of the cancer. Two who took CAAT alone without conventional therapy have been in remission for over six years. Two of the patients who did not survive nonetheless experienced a reduction in tumor size.
CAAT's diet may work partly on the same principle as calorie restriction, as an anticancer effect has been observed in animals placed on a calorie restricted diet. The intent of CAAT is to inhibit the formation of elastin needed for angiogenesis; impair glycolysis, thereby helping to starve the cancer cells, and to inhibit cancer cells' ability to manufacture DNA and various growth factors.
October 10, 2000
New research confirms grape seed extract's many benefits
An article appearing in the August 2000 issue of the journal Toxicology confirmed many health benefits for proanthocyanidins, the potent antioxidants found in grape seeds and other plant foods. Researchers at Creighton University School of Pharmacy & Allied Health Professions in Omaha, Nebraska tested a grape seed proanthocyanidin extract's ability to prevent free radical induced lipid peroxidation and DNA damage. Lipid peroxidation and damage to DNA are two results of free radical damage, which can lead to atherosclerosis, cancer, arthritis, shock, and many other conditions associated with aging. Antioxidants such as proanthocyanidins, vitamins B1, B5, B6, C and E, and beta-carotene quench free radicals and can prevent much of their damaging effects. The researchers found that the proanthocyanidin extract was more effective than vitamin C and vitamin E in both preventing lipid peroxidation and DNA damage in human oral keratinocytes subjected to tobacco induced oxidative stress. The extract also killed human breast, lung and stomach cancer cells and at the same time benefitted normal gastric mucosal cells by enhancing their growth.
Further benefit of grape seed extract was shown by its ability to protect against kidney and liver damage caused by acetaminophen overdose (Tylenol). This is accomplished in part by the extract's ability to regulate the bcl-X(L) gene.
In rats, the extract protected against myocardial ischemia-reperfusion injury and myocardial infarction (heart attack). In humans, the compound also helps relieve chronic pancreatitis. And if that weren't enough, the researchers noted that human volunteers who applied the extract to their skin received enhanced sun protection.
Grape seed derived proanthocyanidins have been shown to offer an array of benefits, and appear to be a wise addition to anyone's life extension regimen.
October 6, 2000
Grain consumption lowers ischemic stroke risk
The September 27 issue of the Journal of the American Medical Association reported that the increased intake of whole grains reduced the risk of ischemic stroke in women. Stroke is the third most deadly disease in this country, ranking only behind heart disease and cancer. Ischemic stroke occurs when a blood clot occludes one of the arteries that supplies blood to the brain, which results in damage to part of the brain due to lack of oxygen. The study's authors sought to determine if increasing whole grains would provide the same protection against stroke as it does against cardiovascular disease in a cohort of women.
As part of the Nurses Health Study, food frequency questionnaires were given to 75,521 women aged 38 to 63 years who had not been diagnosed with coronary heart disease, diabetes mellitus, stroke, or other cardiovascular disease in 1984. The questionnaires were given in 1984, 1986, 1990, and 1994, and participants were followed up for twelve years.
Three hundred fifty-two cases of ischemic stroke were diagnosed in the follow-up period. The study authors noted an inverse association between whole grain consumption and risk of ischemic stroke. This association remained unchanged with adjustment for saturated fat and transfatty acid intake, and was the same for women who never smoked, did not consume alcohol, did not exercise regularly, or who were not on hormone replacement.
October 4, 2000
Memory loss due more to faulty circuits
It has long been believed that the memory loss that occurs with old age is due to a loss of brain cells. A new report in the September 2000 issue of the Journal of Neuroscience challenges that belief with evidence that faulty brain circuits may be the more likely culprit, and that repairing them will be easier than replacing brain cells.
In light of evidence that the cognitive decline that occurs with age can proceed without a loss of neurons, researchers at the Mount Sinai School of Medicine examined the rat brain synapses, which are the areas of communication between brain cells, or neurons. They found that the ability of neurons to carry a signal was reduced in older rats whose learning ability involving the use of a maze was impaired. Reduced neuron conductivity was correlated not with chronologic age, but with the degree of learning impairment observed in the older rats. The decreased neuron activity was concentrated in part of the hippocampus, which is responsible for the abilility to recall facts, and which records conscious, everyday events. It organizes input from the senses via the brain's cortex into memories.
Study coauthor Michela Gallagher of Johns Hopkins University commented, "Most intriguing is that a population of cells in the brain [seems to] act as the conduit for information from the cortex to the hippocampus. The cells that had lost function were all located in a part of the hippocampus that receives signals from the cortex."
The researchers concluded that a decline in the fidelity of input to the hippocampus from the brain's cortex may play a critical role in the cognitive decline of aging. They would now like to determine how this occurs.
October 2, 2000
Early Interferon beta-1a curbs MS
Multiple sclerosis is a progressive, degenerative disease involving demyelination of the nerves. Demyelination results from inflammation, and is defined as a loss of the fatty coating that insulates the nerves, which leads to muscle weakness, tremors, paralysis and/or other conditions. The disease is diagnosed when a patient experiences their second episode of inflammation of a nerve in the brain stem, cerebellum, spinal cord or eye.
In a study published in the September 28 2000 issue of the New England Journal of Medicine, nearly half the patients treated with interferon beta-1a at the time of their first demyelinating event did not go on to develop multiple sclerosis symptoms within the next three years. Interferon beta-1a is currently used to treat MS patients, but it was not known whether the drug was of value in treating the initial demyelinating event. In a randomized, double-blind trial, 383 patients who had evidence of prior subclinical demyelination confirmed by MRI (magnetic resonance imaging) and who were experiencing their first acute demyelinating event were given corticosteroids followed by either weekly intramuscular injections of interferon beta-1a or a placebo. The group receiving interferon beta-1a had fewer new brain lesions and lower brain lesion volume as shown by MRI.
The researchers concluded that MRI scans at the time of an initial MS event are justified, and that treatment with interferon beta-1a is beneficial in patients who are at high risk for multiple sclerosis because they have subclinical demyelinating lesions of the brain. Although they were unable to conduct longterm follow-up with this study, the researchers predicted that preventing a second MS attack will provide sustained benefits.
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