What's Hot Archive
April 27, 2000
Don't stop taking your calcium
A study conducted at Tufts University USDA Human Nutrition Research Center on Aging found that people who stopped taking calcium supplements experienced no longterm moderation of bone loss. At the Experimental Biology 2000 conference, Dr Bess Dawson-Hughes reported the results of a study in which the calcium intake of almost 300 people over age sixty was monitored for two years. All participants had been on calcium supplementation three years prior to the study onset. The individuals who stopped taking calcium supplements resumed bone density loss at the same rate at which it occurred prior to taking the supplemental calcium. The bone loss returned more rapidly in the women studied, resuming after a year without calcium supplements, while it took men two years to experience the same rate. After menopause, women lose bone density at a rate of 1% yearly. Dr Steven Abrams, of the USDA/ARS Children's Research Center in Houston reported finding the same results in adolescents. Dr Abrams stated, "The benefit from calcium supplementation wasn't really held once you stopped it."
This study dramatically illustrates the value of regular supplementation. Calcium is critical for growing children as well as adults. The US Recommended Ddaily Allowance for adults over the age of 50 is 1200 mg. Most people, especially females, are deficient in calcium. Calcium supplementation is the best way to ensure adequate calcium intake. Osteoporosis is a widespread disease, often with lethal consequences. Other helpful nutrients include magnesium, manganese, boron and vitamin D.
April 26, 2000
Glutathione protects against flu
Glutathione is a tripeptide compound synthesized in the body from the amino acid cysteine. There is no form of life that does not contain glutathione. The decline of this powerful antioxidant in the body occurs steadily with aging.
Scientists from Emory University scientists reported at the Experimental Biology 2000 meeting that glutathione could aid in the prevention of flu virus if applied to the mouth and throat. They found that an enzyme that uses glutathione in the detoxification of carcinogens and oxidants is present in the nose and mouth, preventing these chemicals from entering the body, which led to speculation that it might prevent the entry of the flu virus as well.
Dean P. Jones, PhD and colleagues exposed cultured human airway cells to flu virus, without or with glutathione. With high concentrations of flu, glutathione offered no protection, but with lower levels of the virus normally found during the flu, the cells were did not become infected.
Dr Jones stated, "We believe that if we put the glutathione in a lozenge, we could directly expose the virus-susceptible tissues to glutathione over a relatively long period of time. This could be very helpful, for example, if you were sitting next to someone with the flu on an airplane. You could effectively block the infection for a period of several hours . . . There is a natural variation among people in resistance to viruses and in our natural antioxidant system. If we are smokers, if we are deficient in antioxidant vitamins, if we are under stress, or as we become older, we become more oxidized, which makes us more vulnerable to viral infection. This direct exposure to glutathione could be part of an overall strategy to enhance our antioxidant defenses."
April 25, 2000
Calcium fights fat
At the recent Experimental Biology 2000 conference researchers reported that high levels of calcium may aid weight loss. Calcium appears to prevent fat cells' storage mechanisms from switching on. Conversely, diets deficient in calcium stimulate hormones that switch on the preservation of fat within the cells. Acting upon results suggested by an older study of obese men, a team led by Dr Michael Zemel at the University of Tennessee, Knoxville, tested four low calorie diets with varying levels of calcium on obese mice and kept one group on a low calcium, high calorie regimen. Mice who received a low calorie diet supplemented with high levels of calcium carbonate lost approximately 42% of their body fat and one fifth of their weight, compared to a loss of 8% body fat and 11% of body weight in mice who received a diet similar in calorie content, but low in calcium. Mice who received high levels of calcium from dairy products lost 60% of their body fat and weighed 25% less. The scientists are uncertain as to why dietary calcium was more effective than supplemental calcium. Since calcium carbonate, otherwise known as chalk, is a poorly absorbed form of calcium, it could be that the calcium from dairy products was better absorbed. The drawback of dairy products is that their high protein content necessitates large amounts of calcium to neutralize the acidity they create, at times actually resulting in a calcium deficit. Supplements such as calcium citrate are well absorbed and don't have the problem of being associated with high levels of protein. Other dietary sources of calcium include greens such as kale and collards, soy, and calcium fortified products.
Dr. Zemel stated,``For any given level of energy balance -- of calorie intake and physical activity -- dietary calcium helps determine whether calories go to storage in the form of fat, or get burned . . . It doesn't mean that calories don't count.''
Results from human trials will soon be available.
April 18, 2000
Vitamin D deficiency linked with bowel diseases
Vitamin D supplements decreased intestinal inflammation in mice with inflammatory bowel disease (IBD), during a study by Penn State researchers. "Our experiments show that vitamin D deficiency worsens the symptoms of Chron's disease and ulcerative colitis. Treatment with vitamin D for as little as two weeks lessens the symptoms of these inflammatory bowel diseases in mice," said project director Margherita T. Cantorna, who presented the findings at an Experimental Biology conference.
The Penn State team genetically engineered mice to have either Chron's disease or ulcerative colitis and a vitamin D deficiency. Some of the mice received vitamin D supplements with their food. The rest were not fed supplements. Those that received the vitamin supplements experienced less bowel inflammation and lived longer than the untreated mice. Those not receiving supplements began to die at seven weeks and more than half had perished by nine weeks. All of the mice receiving the vitamin were alive at the end of the study.
The skin produces vitamin D when exposed to sunlight. People in northern climates make less of the vitamin than those in warmer, sunnier regions. Chron's disease and ulcerative colitis are more prevalent in North America and Northern Europe. Canada has the highest incidence in the world. IBDs are considered autoimmune conditions, meaning the body attacks itself. During previous studies, Cantorna had found a link between vitamin D and arthritis and multiple sclerosis, two other autoimmune diseases.
"Vitamin D deficiency is more common in people who have inflammatory bowel disease. In addition, the anti-inflammatory drugs often used to treat IBD can cause bone loss as a side effect," Cantorna said. "Vitamin D taken in combination with these drugs may be able to reduce the effective dose of anti-inflammatory needed to treat the disease and decrease bone loss, as well as treat the vitamin deficiency."
April 16, 2000
Micromachines on Medical Horizon
The April 14 issue of Science reported on new nanomachines which are able to detect defects in DNA, paving the way for improved diagnostics. Tiny silicon cantilevers that are less than 1/50 the width of a human hair are coated with biomolecules which have an affinity with certain proteins or DNA. As the DNA binds to the cantilevers, it causes the cantilevers to bend, which is detectable by laser beam deflection. Any slight defect in the DNA will be reflected in the way the cantilevers are bent. The discovery was made by scientists from the University of Basel and IBM.
James Gimzewski of IBM commented, "The ability to use biology to perform specific mechanical tasks on the nanometer scale with silicon provides a completely new approach to operate machinery autonomously, without external power or computer control. We have found a way to get DNA to do the work for us, so w don't need batteries, motors, or the like to operate tiny machines . . . For instance, we can envision a system to attack cancerous growth: the release of just the proper doses of chemicals in the appropriate location of the body could be achieved using tiny microcapsules equipped with nano-valves . . . They could be programmed chemically to open only when they get biochemical signals from a targeted tumor type. This would enable the right therapy at the right place at the right time, with minimized side effects and no invasive surgery."
Christoph Gerber, also of IBM believes that the biomechanical technique will create the ability for rapid, mobile biochemical analysis, for example, enabling heart attack to be diagnosed in those experiencing chest pain.
April 15, 2000
Radiation and chemotherapy controls head and neck cancer
Combining intensive radiation and chemotherapy treatments improved survival rates for patients with locally advanced head and neck cancer, eliminating the need for surgery in most cases. Head and neck cancers grow rapidly; often originate in the sinus cavities, mouth, tongue, pharynx, larynx or upper esophagus; and spread to nearby tissue. Most patients die from a local recurrence, even after aggressive treatment. Head and neck tumors are slow to metastasize to distant sites. Conventional treatment involves extensive and debilitating surgery, and post-operative radiation treatments.
Researchers from the University of Chicago Medical Center and Northwestern University treated 76 patients with three anticancer drugs and administered twice daily radiation therapy directed at the tumor bed for five days. Patients rested for nine days and repeated the treatment regimen, alternating the aggressive therapies with rest through five cycles. In the Journal of Clinical Oncology the team reported that 92 percent of the patients obtained complete local control of the malignancy, but seven percent needed surgery at the primary cancer site.
"We were able to produce an exceedingly high local control rate, avoid surgery and dramatically improve patient survival," said study director Dr. Everett Vokes, at the University of Chicago. "But those gains came at a cost of frequent and severe side effects." During the treatment, patients experienced difficulty swallowing, mouth pain and damage to blood-cell producing bone marrow, which results in a diminished ability to fight germs. Four patients died from infections brought on by the decrease in their immune function. Researchers have begun a new study using different drugs that should cause fewer side effects. "We need to find ways to make therapy easier on the patient and better methods to prevent distant spread," Vokes said. But this study proves that we can control local disease, usually without surgery."
April 12, 2000
Neuronal transplantation helps some stroke patients
Transplanting neurons into the brains of patients who have suffered a stroke restored motor function for some participants. Twelve men and women, between ages 44 and 75, participated in the University of Pittsburgh Medical Center phase 1 trial, investigating the safety and feasibility of human neuronal cell transplants. The patients' neurologic deficits had been stable for at least two months prior to the implant. Neurosurgeons injected human neuronal cells into sites within the brain. The first four patients received two million neurons at three sties along the basal ganglia. The others were given either two million neurons along a single needle pass or six million neurons along three paths. CT scans helped surgeons determine the proper placement. Eight patients reported increased strength, sensation and coordination. Doctors found that six patients scored better on the standard European Stroke Scale, three experienced no change on the tests and three slightly deteriorated.
"The changes in performance on the motor function of each of these scales accounted for the majority of improvement noted," said Dr. Douglas Kondziolka, who reported the findings at the annual meeting of the American Association of Neurological Surgeons. "Functional improvement appeared to be independent of the time interval since occurrence of the strokes. Increases in cerebral glucose metabolism as measured by PET scanning appeared to correlate with functional improvement."
Surgeons obtained the implanted human neuronal cells from a California company. The cells originated from a tumor in the reproductive organs of a cancer patient obtained during the 1980s. The company altered the cells so they cannot divide. Animal studies showed neuron impants reversed cognitive and motor deficits brought on by a stroke.
April 12, 2000
Dual mode of action provides novel approach to treating Alzheimer's
People trying a new treatment for Alzheimer's disease experienced significant cognitive, functional and behavioral improvement during a five month study. Like other Alzheimer's drugs on the market, galantamine (or Reminyl®), maintains acetylcholine levels by blocking the enzyme acetylcholinesterase from breaking down acetylcholine. Low levels of acetylcholine contribute to the disease's symptoms. What makes this drug different is that laboratory studies show galantamine also indirectly acts on nicotinic receptors to release more acetylcholine.
"For the first time, we are able to show that Reminyl has benefits not only on cognition, but on patients' ability to function, while also postponing the emergence of behavioral symptoms," said Dr. Pierre Tariot, at the University of Rochester Medical Center, in New York. "Even the most basic improvement of symptoms, such as being able to prepare a meal on their own or remembering the events of the day, can provide relief for patients and often their caregivers."
The placebo-controlled trial involved 978 patients with mild to moderate Alzheimer's disease. They received either an inactive placebo or one of three doses of the real drug. Results were measured using standard assessment tools. Patients receiving the two higher doses scored higher on the functional tests at the end of the five month study period than those taking the placebo. Mild and transient gastrointestinal side effects were noted. The findings were reported at the International Stockholm/Springfield Symposium, a meeting of Alzheimer's therapy experts.
Another study presented at the meeting found the drug's memory, learning and decision-making effects last at least 12 months. "The results from this study show that ongoing, continuous treatment with Reminyl can help patients maintain daily functioning without further cognitive deterioration for an entire year," said Dr. Luc Truyen, with Janssen Research Foundation, the company developing the drug.
April 12, 2000
Stem cells may aid in cancer fight
More than 110,000 people receive a brain tumor diagnosis annually; 80,000 cases result from metastasis from a distant cancer site, most commonly lung, breast, melanoma or kidney. Boston researchers, investigating the use of neural stem cells to fight the disease, found that when they injected the stem cells into the brains of mice with cancer, the stem cells honed in on the tumor. The neuroscientists say this indicates the cells might prove to be helpful as chemotherapy delivery vehicles in treating adults with brain tumors. The stem cells may also be able to stop tumor growth . "One of the problems in treating malignant brain tumors is that these lesions are not confined. They infiltrate into the surrounding brain tissue. Consequently, novel ideas are needed to enable neurosurgeons to deliver therapy that can reach these isolated tumor cells," said Dr. Joseph M. Piepmeier, chair of the American Association of Neurological Surgeons.
Neural stem cells are immature cells harvested from developing central nervous system tissue. The cells can mature into a variety of cell types. During the pilot study, researchers observed that after a couple weeks, even after injecting the cells far from the main tumor, the stem cells were rapidly distributed throughout the tumor bed and followed aggressive cancer cells that were migrating into surrounding healthy tissue. At the annual meeting of the American Association of Neurological Surgeons researchers reported that transplanted therapeutic genes may also produce a tumor-killing effect or inhibit tumor cell division.
"Malignant brain tumors remain virtually untreatable and are inevitably lethal, despite surgical excision and radio- and chemo-therapy," said Dr. Karen Aboody, at Children's Hospital in Boston. "This new tumor targeting ability, if reliably reproducible, could result in novel and more effective therapies for previously intractable brain tumors."
April 12, 2000
One gene may hold link to aging diseases
Discovering a common genetic link to a variety of age-related diseases, researchers at the University of Illinois at Chicago (UIC) say their findings suggest the possibility exists that someday drugs targeted at the p21 gene could prevent or treat cancer, atherosclerosis, arthritis and Alzheimer's disease.
The p21 gene stops cells from dividing when they become old and halts cell growth allowing for repair if the cell is damaged by toxins or radiation. UIC researchers, using recombinant DNA techniques, turned on the p21 gene in laboratory samples of human cells and watched as the cells stopped growing, became flatter and more granular, and produced enzymes associated with aging cells. "The pattern was striking," said Igor Roninson, Ph.D., the senior author of the report in the journal Proceedings of the National Academy of Sciences. "Turning on this one gene brought about changes in numerous other genes that have already been implicated in aging and age-related diseases."
The team investigated how other genes responded to p21 stimulation and found that p21 selectively inhibited more than 40 genes associated with cell replication, halting growth, and that it increased activity in approximately 50 other genes. About 20 of those 50 were genes that produce proteins, some of them inhibiting cell death or stimulating growth of nearby cells. The researchers were surprised by this finding and say the "paradoxical growth-stimulating activity of growth-arresting cells" resembles some cancer cell functions, suggesting a link between p21 and tumor development. Other genes produced proteins associated with Alzheimer's disease, arthritis, atherosclerosis and development of other age-related diseases. Researchers are now testing if p21 acts the same way in other human tissue and are developing a drug to limit p21's disease-promoting properties.
April 11, 2000
Stimulating stroke patients' brains may aid rehab
Stroke and brain injury creates faulty connections in the cerebral cortex which causes patients to experience difficulty coordinating movements or performing tasks. Patients typically regain only limited function, causing experts to think that the brain is hard wired early in life and remains unchanged in adulthood. But now scientists believe that connections in the cortex, which controls voluntary movement, speech and reasoning, are continuously modified by experience and learning.
Researchers were aware that in blind Braille readers, the area of the cortex associated with the reading finger is larger than nonreading fingers. During a study reported in Experimental Brain Research, scientists at Adelaide University, Australia, stimulated participants' cerebral cortexes with electronic coils and measured the activity produced after exciting nerves in the subjects' fingers. The team found they were able to change the size of the brain's response and that the alterations lasted after the stimulation ended. Differently shaped coils produced distinct patterns of stimulation. The noninvasive coils are held close to the participants' head and cause no pain. The findings will help in understanding how people learn.
"It also suggests new directions for developing potential therapeutic approaches to disordered brain function in such debilitating conditions as stroke," said lead investigator Dr. Mike Ridding. "By developing a method of stimulating the pathways leading back to the brain from the affected muscles, we may be able to encourage the development and use of an alternative cortical area to that damaged by the stroke. If we could achieve this, it would be a big step towards enabling patients to regain at least some of the movement control they lost as a result of their stroke."
April 11, 2000
Osteoporosis widespread, deadly
The National Institutes of Health Consensus and Development conference on osteoporosis concluded with the statement that osteoporosis does not just effect postmenopausal women and the elderly. Men with prostate cancer, people taking certain types of steroid drugs and young women with eating disorders are at special risk. Children who obtain insufficient calcium, a common deficiency, are likely to suffer from bone loss later in life. Panel Chair Dr Anne Kilbanski of Harvard Medical School stated, "Osteoporosis occurs in all populations and at all ages and is a devastating disorder with significant physical, psychosocial and financial consequences."
Osteoporosis is a progressive loss of bony tissue that causes 1.5 million fractures each year. Although estrogen replacement is frequently utilized in the prevention and treatment of osteoporosis, the conference panel of experts felt that more information was needed on how it works. Phytoestrogens, it was announced, are not helpful in preventing fractured bones.
In a study conducted on 6,459 women with low bone mass published in the March Journal of the American Geriatrics Society, it was reported that older women with vertebral deformities had a greater risk of hospitalization and death than women with without the deformities. Study head Dr Kristine E Ensrud believes that further study leading to more aggressive treatment is needed. Dr L Joseph Melton II of the Mayo clinic commented, "Because vertebral fractures are extremely common, affecting up to one-quarter of postmenopausal women, any increased risk of death in these patients is a serious matter."
April 10, 2000
Low vitamin C levels associated with gallbladder disease
Vitamin C supplements may protect women from gallbladder disease, while having low levels of the vitamin (also known as ascorbic acid) could increase risk of the painful condition, according to a 13,130 person study reported in Archives of Internal Medicine.
The gallbladder is a small sac that stores bile, a fluid that helps the body digest fat. Gallstones form when an overabundance of cholesterol in the bile hardens. Previous animal studies showed a correlation between vitamin C deficiencies and development of gallstones. University of California, San Francisco researchers investigated the possibility that the same relationship exists in humans. "Because vitamin C regulates the conversion of cholesterol into bile acids in experimental animals," said Dr. Joel Simon, at the San Francisco Veterans Affairs Medical Center, "we hypothesized that low levels of vitamin C may be a risk factor for human gallbladder disease as well."
Researchers measured blood levels of ascorbic acid and conducted ultrasound exams to look for asymptomatic gallstones, undiagnosed stones that had not yet become painful. They found an increased prevalence of gallbladder disease in women, but not men, who had low levels of ascorbic acid. A 0.5 mg/dL increase in women's ascorbic acids levels reduced the incidence of symptomatic gallbladder disease by 13 percent. And in women taking vitamin C supplements or multivitamins containing vitamin C, the incidence of symptomatic gallbladder disease dropped by 34 percent. Similar associations occurred in women who were unaware they had gallbladder problems and had not made any dietary changes as a result of the diagnosis.
"The size of our study and the collection of data on undetected gallstones strengthens the hypothesis that vitamin C levels may be an important risk factor for gallstone formation, at least among women," said Simon. "Because the study was conducted among a random sample of Americans, our results should be generalizable to the U.S. population."
April 10, 2000
American ginseng lowers blood sugar
Canadian studies show American ginseng can lower blood sugar when taken before a meal and may serve as a treatment and preventive measure for diabetes mellitus.
During the study, reported in Archives of Internal Medicine, Type-2, adult-onset, diabetic and nondiabetic participants received either an inactive placebo or 3 grams of ground American ginseng, 40 minutes before or during a test meal. Diabetics experienced a 20 percent decrease in blood sugar levels when taking the ginseng compared to those taking placebos. Researchers observed a similar decrease in nondiabetics when they consumed the ginseng before, but not during, the meal, suggesting the importance of timing. Researchers did not evaluate Chinese, Japanese or other types of ginseng. "Although preliminary, these findings are encouraging and indicate that American ginseng's potential role in diabetes should be taken seriously and investigated further. Controlling after-meal blood sugar levels is recognized as a very important strategy in managing diabetes. It may also be important in the prevention of diabetes in those who have not yet developed the disease," said lead investigator Dr. Vladimir Vuksan, at St. Michael's Hospital and the University of Toronto. "This study represents an important step in the evaluation of herbals. A major criticism of the herbal field and past ginseng research has been the lack of scientific, placebo-controlled trials in humans. Our study applied traditional clinical trial standards to research on an alternative medical product."
Nearly 16 million Americans have diabetes. A third do not realize the have the disease, according to the American Diabetes Association. Incidence of Type 2 diabetes increases with age. About 18 percent of those over 65 have the condition. People with diabetes do not properly produce or use insulin, a hormone that converts sugar and other foods into energy. There is no cure, only management with medications, diet and exercise.
April 9, 2000
New antibiotic may overcome resistance
University of Wisconsin, Madison researchers have designed a new antibacterial molecule that was effective against two species of bacteria resistant to common antibiotics. The discovery, reported in the British scientific journal Nature, highlights the potential of developing a new class of antibiotics to fight resistant bacteria, a growing problem.
"Nearly all antimicrobial agents now used in clinical settings are naturally occurring molecules, or are closely related to molecules found in nature," said author Samuel H. Gellman. "In contrast, our new antimicrobials are very different from all molecules found in nature. The upshot of this research is that we may be on a radical new path that may lead to the rational, deliberate design of clinically useful molecules like antibiotics."
The new, synthetic agent mimics naturally occurring peptides known to fight microbes, but is more stable and less toxic to human cells. The Wisconsin team's beta-peptide molecule killed a variety of infectious bacteria, including two species (Enterococcus faecium and Staphylococcus aureus) associated with resistance to most approved antibiotics. Scientists still are not sure how the peptides work. They suspect the molecule breaks the microbe's outer surface and interferes with its inner workings, a different mechanism than used by traditional antibiotics.
"These things seem to be able to disrupt the bacterial membrane. When that happens, all hell breaks loose with the bacterium," Gellman said. "We don't think our new molecules will be compromised very quickly by resistance. These beta-peptides have no precedents in nature, unlike traditional antibiotics. Chemically, they are completely unlike the kinds of things bacteria typically see."
April 8, 2000
Hard-driving personality not always unhealthy
A hard-driving, controlling personality may not be as damaging to a person's health as previously thought. Duke University Medical Center researchers found that men with this personality trait could accomplish a great deal without raising their blood pressure or suffering from other stress-related conditions, as long as they were not hostile and could exert a fair amount of control over their work and career advancement.
Researchers studied how 74 healthy African-American men, ages 18 through 47, responded to a stressful scenario and found that cortisol rose to dangerous levels in men with super-charged personalities and little influence over their careers. The adrenal gland releases cortisol to help maintain energy levels during stressful situations. Too much cortisol can increase blood pressure and suppress immune function. Men with hard-driving personalities produced more cortisol than mellow types, but the amount did not increase to an unhealthy level except in men with little control of their work life. "Vigorously responding to work stressors can be a positive coping strategy, if you have influence over the stressors you are handling," said Gary Bennett Jr. "But when you continually encounter stress in your job that cannot be alleviated, your body reacts to that by overproducing stress hormones."
Experts have known for a long time that people with low job control face greater risk for ill health. This study, presented at the Society of Behavioral Medicine's annual meeting, suggests why. "Hard-charging people feel good about themselves and their jobs if they have a good income, good work environment and good social support. But when you don't have these, the experience of dealing head-on with stress can be a negative one," said Bennett, who plans to study if the results hold true for women, whose coping styles and support systems may alter their stress response.
April 7, 2000
Genetically engineered bacteria, plus radiation fights tumors
By combining a new bacteria-based drug treatment with traditional radiation therapy, Yale Cancer Center scientists suppressed solid tumor growth and prolonged survival of mice at rates surpassing results for either treatment alone. The team used a genetically altered form of the bacteria Salmonella developed by Yale researchers a few years ago. In its normal state, Salmonella can cause food poisoning and septic shock. When scientists tested the altered bacteria during animal studies, the drug prolonged the lives of mice with melanoma, without causing infections. Human trials are now under way, using the altered bacteria to target solid tumors. " For a number of reasons, we thought that combining these Salmonella with x-ray treatments might be good strategy improved therapysaid Dr. John Paweleksenior research scientist at the Yale University School Medicine. It was exciting to see positive results."
During a recent animal study, reported at the annual meeting of the American Association for Cancer Research, Yale scientists combined the antitumor drug with radiation treatments in mice with breast cancer, colon cancer and melanoma. Animals receiving both treatments fared better than those receiving either treatment alone. The results exceeded scientists' expectations of possible additive effects.
"It appears that the combination of genetically engineered Salmonella with radiotherapy could be a new and beneficial treatment for solid tumors," Pawelek said. "Because of the large number of cancer patients who receive radiation therapy, the potential impact of this finding is tremendous."
April 7, 2000
Soy helps heart without upsetting hormone levels
Experts have known for sometime that soy benefits the heart and many other conditions, but some people have expressed concern about its natural plant estrogens. A new study published in the journal Metabolism should lay those fears to rest, according to its author Dr. David Jenkins of the University of Toronto. His research showed soy decreased oxidized cholesterol levels without raising hormone levels. "The concerns have been whether soy estrogen might lead to hormone-dependent breast cancer or abnormal sexual development in children, yet we found no evidence to support this," Jenkins said.
Two groups of study participants ate a low fat diet, either with or without soy foods, during two one month periods. The researchers determined estrogen levels by analyzing 24 hour urine samples collected at the end of each month. They tested the urine using breast cancer cells, because estrogen stimulates the cancer cells to release a specific protein. The team determined quantities of the protein produced from each urine sample to measure the amount of estrogen present. Total estrogen activity decreased in women eating soy. "This finding suggests that soy may not have the estrogenic effects that were thought to alleviate menopausal symptoms, but it refutes claims about its purported hormone risks," Jenkins said.
The study also found that soy decreased the risk of heart disease by reducing oxidized cholesterol levels, which coronary artery walls take up more quickly to form plaque. Previous research by Jenkins had shown that consuming soy lowered total cholesterol levels, decreasing LDL (bad) cholesterol without lowering HDL (good) cholesterol.
April 6, 2000
Researchers find host gene that helps viruses to multiply
Learning how and when a virus commandeers a yeast's cellular gene in order to multiply, researchers at the Howard Hughes Medical Institute at the University of Wisconsin, Madison, say their discovery offers insight into the relationship between a virus and host cell that could lead to new genetic strategies to combat infections such as the common cold, hemorrhagic fever, polio and hepatitis. "This is the first genetic identification of an intracellular host factor that contributes to the ability of the virus to copy its genes," said coauthor Paul Ahlquist. Until now, virologists only knew that hosts aided RNA viruses through changes to cell surface proteins that assist the viruses in entering host cells. "Loss or mutation of this gene severely inhibits multiplication of the virus," he continued.
RNA viruses, which comprise about a third of all known viruses, rely on host cell resources. "By using some of the cell's machinery, viruses can copy their genomes and make viral proteins to be assembled into new virus particles which, in turn, go on to infect other cells," said lead author Juana Diez.
Although this study, reported in the journal Proceedings of the National Academy of Sciences, involved a yeast host, researchers expect a similar process occurs between viruses and other host organisms, including humans, because all RNA viruses appear to use some common methods of replication. Understanding how RNA viruses use host cells to multiply will help scientists develop antiviral treatments to combat a number of viruses and design ways to cripple changes viruses make to avoid host defenses. "Such mutation is a significant problem in controlling RNA viruses," said Diez. "Using antiviral drugs to attack the viral multiplication process, which mutates more slowly than some other virus features, is a promising strategy to control RNA virus infections."
April 6, 2000
New radiotherapy technique highly successful against cancer
The February 15 2000 issue of the Proceedings of the National Academy of Sciences reported on a new proprietary radiotherapy technology that, administered in one dose, cured implanted cancers in 28 out of 30 mice. (Disappearance of the tumor with absence for one year was considered a cure.) NewRx Corporation's scientists injected a radiotherapy drug and targeting antibody separately at different times. The two drugs join at the tumor where the antibody locates, limiting radiation exposure to healthy tissue. The body promptly eliminates radiation that does not join the antibody.
Conventional radioimmunotherapy uses radiolabeled antibodies to deliver doses of radiation directly to the cancer site. Because some cancer cells contain antigens that cause the formation of tumor-specific antibodies, these antibodies can be made in the laboratory and attached to radioactive substances (a process known as radiolabeling). Upon injection, the antibodies seek out the cancer cells which are destroyed by the cytotoxic action of the radiation. However, this process causes radiation damage to healthy tissue as the antibodies circulate in the blood, limiting the amount of radiation that can be delivered. New Rx's new technology, called PretargetR allows a higher dose of radiology to be used. Neo Rx's chief executive officer, Paul G Abrams, MD, JD stated, "We expect to begin formal Phase I trials with at least one PretargetR product this year. Using a prototype PretargetR product in patients with lymphoma, we have already observed three complete remissions in the 7 patients treated . . . As in the animal studies reported in our manuscript, these responses were observed after a single dose of PretargetR. Moreover, we began our clinical study at a dose higher than the maximum tolerated dose of conventional radiotherapy products, yet we did not see any clinically significant toxicity."
April 6, 2000
Dental x-ray may help predict heart attack or stroke
Standard panoramic dental x-rays may serve as accurate tools in providing early warnings of clogged arteries, which increase the risk of heart attack or stroke. University at Buffalo (UB) School of Dental Medicine researchers pioneered the idea of using dental films as a cardiovascular risk screening tool. Early awareness that arterial plaque has built up allows doctors to take preventive measures. The calcified arterial plaque that shows up on the panoramic x-ray alerts the dentist that a cardiovascular problem exists, but it cannot determine the extent of the problem.
During the current study, the UB team compared calcification with cause of death in a homogenous Native American population at high risk for developing diabetes. Researchers were able to evaluate a wide variety of information, including dental x-rays and death statistics, collected from the group during previous studies. They discovered calcium deposits in the carotid arteries of 7.5 percent of the 818 participants, compared to only about 3 percent of the general population. The UB researchers found that subjects with calcified plaque were twice as likely to die from stroke or heart attack as those without plaque.
"Results of this study move us closer to the use of panoramic dental radiographs as a screening tool for all cardiovascular disease," said lead author Laurie Carter, D.D.S., Ph.D. "It is a very significant step in that direction. However, we need more of this type of research in a general population."
April 6, 2000
Vegetarian Diet Eases PMS Symptoms
Women following a low fat, vegetarian diet can experience a significant reduction in pain related to premenstrual syndrome (PMS), according to a study in the February issue of Obstetrics & Gynecology (Vol 95, No 2: 245-250). The results of the study, which tracked 33 women over a one year period, showed that subjects reported a decrease in pain severity, as well as 1.5 fewer days of pain each month. The diet apparently also relieved water retention and concentration problems, increased energy levels, and lowered cholesterol levels.
The authors, who are researchers at the Physicians Committee for Responsible Medicine (PCRM), a Washington DC based organization, advise that trying the diet for just one month would be enough to yield positive results for many PMS-stricken women. Lead researcher and PRCM president and nutrition researcher, Neil D. Barnard, M.D., reports that, "For some women, the change was profound. Their pain was gone or dramatically reduced, something they had not experienced in years. If they needed any pain medicine at all, they needed much less than before".
The study's theory is that reducing fat in turn decreases estrogen levels and the resultant production of prostaglandins that cause pain symptoms. Moreover, a high fiber, vegetarian diet may increase a blood protein called "sex hormone binding globulin", which binds to and suppresses estrogen in the blood, thus suppressing hormone swings associated with PMS. In fact, results showed that following a two month vegetarian diet phase, there was a 19% increase in sex hormone binding globulin levels, while body weight dropped by an average of 2.7 kg among participants.
Previous studies have shown that vegetarian diets can increase serum sex-hormone binding globulin, and reduce weight. Another study involving Danish women found that a higher intake of omega-3 fatty acids lowered menstrual pain. Vegetables, fruits, and legumes are high in omega-3 fatty acids, which are precursors of 3-series prostaglandins and have an anti-inflammatory effect.
April 6, 2000
Drug derived from the South African willow bush fights cancer and other diseases
A drug derived from a South African willow bush decreased blood flow to some patients' inoperable cancer tumors that had not responded to traditional chemotherapy. The drug, combretastatin A4P (CA4P), targets and reduces or destroys existing blood vessels, unlike another new class of drugs, angiogenesis inhibitors, that stop new vessels from forming (a process called neovascularization). Vessels formed by tumors have a different architectural and biochemical make-up than normal blood vessels, which enables CA4P to attack the new vessels without damaging blood supply to normal tissue.
Patients participating in a Phase 1 clinical trial at the University of Pennsylvania Cancer Center received intravenous doses of the drug for five consecutive days, every three weeks. Researchers evaluated tumor blood supply prior to and at the end of the treatment cycles. In five of the nine patients receiving the highest dosage, doctors observed a decrease in blood flow during monitoring with MRI scans. Most patients safely tolerated the vascular targeting agent. "These early results are promising and suggest that combretastatin may affect tumor blood supply," said lead author Dr. James P. Stevenson, who reported the findings at the annual American Association of Cancer Research meeting. "We will continue investigating this drug for its potential benefits in fighting advanced cancers."
Studies show that in addition to battling cancer, CA4P has potential for treating other diseases that form new blood vessels, such as macular degeneration, psoriasis and arthritis, according to OXiGene, the company that developed the drug. "Combretastatin A4 Prodrug accelerates the regression rate of preformed vessels in the eye of experimental animal models. Ophthalmologists generally see patients who already have neovascularization, and so the drug may have application to disorders such as diabetic retinopathy and age-related macular degeneration," said Donald Armstrong, Ph.D., at the University of Florida, College of Veterinary Medicine.
April 5, 2000
Older tea drinkers have stronger bones
About 10 million Americans suffer from osteoporosis. Their bones become porous and more prone to fractures. Another 18 million have low bone density, putting them at increased risk for the painful and debilitating disorder. High caffeine intake has been associated with decreasing bone density. But a new British study, reported in the American Journal of Clinical Nutrition, found that while tea contains caffeine, it also offers protective benefits.
Researchers at Cambridge University evaluated the skeletal bone density of 1,256 older women, including 1,134 tea drinkers, and found the tea drinkers had greater bone mineral density in the lumbar spine and in a portion of the thigh bone, called the greater trocanter, than non-tea drinkers. Bone density in the femoral neck was similar in both groups. Tea drinkers overall mean bone mineral density was five percent greater than non-tea drinkers, which the researchers equate to a 10 to 20 percent decrease in fracture risk. Tea drinking proved beneficial independent of participants adding milk to the beverage, smoking, drinking coffee or taking hormone replacement therapy. Researchers suspect the positive effect occurs due to isoflavonoids in the tea, which produce a weak estrogen effect. Estrogen decreases osteoporosis risk and is one of the reasons some postmenopausal women decide to take hormone replacement therapy.
April 5, 2000
Cancer vaccine mobilizes immune system to fight cancer
Firing up the immune system with a vaccine bolsters the body's ability to attack and kill cancer cells. In test tube studies, researchers at the University of California, San Diego developed a prototype vaccine that activated immune-system cells, called cytotoxic T-lymphocytes (CTL), to target telomerase, an enzyme that leads to uncontrolled reproduction of cancer cells. Telomerase activity is increased in most human tumors, making it an easy target for an attack by CTL. "In cancer, the immune system becomes increasingly weakened and ineffective against rapidly proliferating malignant cells," said Dr. Maurizio Zanetti. "We wanted to see if the immune systems of individuals with cancer retained the ability to recognize telomerase, and if we could boost the immune response using telomerase in a prototype vaccine to expand CTL activity against cancer."
The California researchers made a vaccine that would target telomerase made from CTL-specific pieces of telomerase reverse transcriptase (hTRT) from prostate cancer patients' blood cells. After receiving the immunization, lymphocytes from prostate cancer patients quickly attacked. The scientists also tested the response of other human breast, colon, lung and melanoma cancer cells by adding CTL produced from the prostate cancer patients. They found that these lymphocytes also focused in on the hTRT peptides and destroyed them. Mice, genetically engineered to mimic human immune systems, produced a CTL response to the vaccine and displayed no apparent side effects. The team also tested the vaccine on human stem cells and saw no adverse activity. Researchers doubt the vaccine presents any danger of provoking an autoimmune reaction, but said the possibility warrants further study. These results, reported in the journal Proceedings of the National Academy of Sciences, indicate that telomerase could serve as a basis for a universal cancer vaccine that could treat many types of cancer.
April 5, 2000
Two biomarkers help predict breast cancer relapse
Biomarkers may help doctors predict which women with breast cancer are at higher risk for a recurrence, allowing others to avoid postoperative chemotherapy, according to German researchers reporting at the annual meeting of the American Association for Cancer Research. Women whose cancer has spread to lymph nodes routinely receive chemotherapy after surgery. The decision to add drugs to the treatment plan for node-negative patients has been more difficult. During a multicenter trial, a team from Munich's Technical University investigated if measuring the levels of two biomarkers, a protein called uPA (urokinase-type plasminogen activator) and its type-1 inhibitor PAI-1, could aid in determining the need for chemotherapy. The two substances have been associated with a poor prognosis in women with node-negative breast cancer.
The study assessed uPA and PAI-1 levels in tumors from 556 node-negative breast cancer patients. They found low levels of both biomarkers in 241 patients. These women received no chemotherapy. The other 315 women were divided into two groups and received either a commonly used, three drug chemotherapy combination or observation with no treatment. After a median 32 month follow-up, relapse risk was less than 10 percent for node-negative women with low levels of uPA and PAI-1. Chemotherapy reduced the chance of recurrence by 43.8 percent in women with high levels of the biomarkers. The researchers recommend routine uPA and PAI-1 testing of primary tumors in node-negative patients and suggest doctors use the information to determine relapse risk and the need for post-operative chemotherapy. "We have found that these two markers are unique among prognostic factors in breast cancer in that they have consistently demonstrated a correlation with both duration of disease free survival and overall survival," said Dr. Anita Prechtl.
April 5, 2000
Urine test developed to detect prostate cancer
Finding prostate cancer before it spreads increases men's odds of survival. Researchers at Fox Chase Cancer Center in Philadelphia and Johns Hopkins University in Baltimore have developed a method of analyzing urine for a common genetic change associated with prostate cancer, called hypermethylation at the glutathione-S-transferase (GSTP1) gene. "Prostate cancer is curable if detected early and it is likely that there are cancer cells in body fluids years before cancer is clinically detectable. If we can find those cells, we can cure more prostate cancers," said Paul Cairns, Ph.D., of Fox Chase Cancer Center.
The scientists collected tumor and urine samples from 28 men with prostate tumors that had not spread. Using a sensitive PCR (polymerase chain reaction) test, they found the genetic change in 22 of the tumor samples. They tested urine samples collected from these 22 men and found the same DNA marker in six of the urine samples. None of the urine tests produced a false positive result. Although the numbers are low, during a presentation at the annual meeting of the American Association for Cancer Research, the researchers said they demonstrated for the first time that diagnosing prostate cancer is possible through a urine test. Researchers at Johns Hopkins University previously had developed a urine test to assess for bladder and kidney cancers.
"We are optimistic that future research and continuing improvements in molecular technology will increase the detection rate. Screening tests should be reliable, inexpensive and noninvasive. Urine tests meet these standards," said Cairns. "In the future, it's quite possible that the same urine specimen could be used to test for prostate, bladder and kidney cancer."
April 5, 2000
Gene mediates stress response in male mice
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A hormone receptor, found in the pituitary gland and brain, has been found to decrease the stress response in mice, according to a report in the journal Nature Genetics. The discovery aids the understanding of physiologic reactions to stress. When the body is exposed to stress, the hypothalamus secretes corticotropin-releasing hormone, which prompts the pituitary to release chemicals that tell the adrenal gland to produce hormones that increase feelings of anxiety, boost energy. raise blood pressure and suppress immune response.
Two corticotropin-releasing hormone receptors exist, Crhr1 and Crhr2. Researchers at the University of California, San Diego found that turning off the Crhr1 receptor did not increase anxiety. When the team measured the response to bright lights and heights of mice without the Crhr2 gene , male mice without Crhr2 acted more anxious than normal mice. "These two receptors had overlapping but clearly distinct anatomical patterns of expression in the brain," said investigator Michael G. Rosenfeld. "Crhr2 also responds to a different chemical trigger, called eucortin."
Male mice with only one copy of the gene reacted more anxiously than normal mice but showed less distress than those without the gene. The team also induced anxiety by administering a drug that blocked the Crhr2 receptor. Female Crhr2-deficient mice did not exhibit similar anxiety. The anxiety produced by the Crhr2 deficiency did not alter the mice's hypothalamic-pituitary-adrenal stress response. The team said it reflects impaired responses in areas of the brain controlling emotional and autonomic function, because they noted markedly lower levels of gene-regulatory transcription factor CREB phosphorylation in male mice lacking Crhr2. The discovery could lead to new drug development. "Basically, we have found that the Crhr2 receptor in some areas of the brain responds to Crh and acts to oppose the anxiety response," Rosenfeld said.
April 4, 2000
SAANDs compounds aid in treating cancer
New compounds designed to trigger the death of abnormal precancerous and cancerous cells hold promise for the treatment of breast, prostate and colon cancer. Unlike traditional chemotherapy drugs, the new selective apoptotic antineoplastic drugs (SAANDs) target cancer cells without damaging normal tissue. Researchers from several institutions reported findings from their studies at the annual meeting of the American Association for Cancer Research.
Dr. Margie Clapper, at the Fox Chase Cancer Center, explained how the SAAND called Aptosyntm prevented precancerous colon polyps in patients with familial adenomatous polyposis. Patients with this rare hereditary condition have a predisposition to colon cancer.
Working with mice who received implanted tumors, researchers at the company Cell Pathways found that another drug, CP461 (a second generation SAAND compound), significantly enhanced the ability of paclitaxel, marketed as Taxol(tm), to fight breast cancer. The mice received a nontherapeutic dose of the SAAND, Taxol or a combination of both agents. Tumors in mice treated with both drugs shrunk significantly more during treatment and for one month afterward than tumors in mice treated only with Taxol. "This research suggests that CP461, given in combination with paclitaxel, may potentially increase paclitaxel's efficacy in breast cancer without adding any additional side effects," said Dr. Rifat Pamukcu, with Cell Pathways.
Columbia University researchers found that SAAND compounds Aptosyn, CP248 and CP461 blocked prostate cancer growth in two ways. They induced cell death and decreased androgen receptor expression in cancerous prostates, which made the cells less responsive to male hormones. When used with cancer cell lines, the drugs caused cell death and at the same concentration inhibited cellular expression and secretion of prostate specific antigen. "Because of their dual mechanism of action, these agents are also effective in prostate cancer cells that have become independent of androgens," said Columbia senior investigator Dr. Bernard Weinstein.
April 4, 2000
Soy proteins without isoflavones decrease breast tumors in animals
Epidemiological studies have found that premenopausal women in Japan and parts of China, where people eat greater amounts of soybeans than in Western cultures, have a lower incidence of breast cancer than Western women. But scientists still do not know for sure how or what part of the soy protein provides the protective effect. Working with rats, researchers at the University of Illinois at Chicago found all the soy compounds they tested decreased the number of mammary gland tumors in the animals, but soy protein mixes without isoflavones, a type of naturally occurring plant estrogen, were most effective.
The study fed five groups of rats modified corn starch diets supplemented with the isoflavone genistein, another isoflavone called daidzein, a combination of both of these isoflavones, a soy protein mixture containing the same two isoflavones or a soy protein mixture without the plant estrogens. A sixth, control group received no supplement. They induced mammary cancer in the rats and observed the responses. The researchers saw no difference in the incidence of cancer or survival. However, the number of tumors was reduced in rats receiving daidzein, the soy mixture with isoflavones and, most significantly, in those consuming the soy mixture without isoflavones. The soy mixtures increased production of detoxification enzymes that remove free radicals which have cell-damaging properties. The team did not isolate which component of the soy protein mixture provided the anticancer benefit. Dr. Andreas Constantinou presented the results at the annual meeting of the American Association for Cancer Research.
April 4, 2000
Estrogen may speed growth of lung cancer
Estrogen has long been associated with stimulating breast cancer growth. Now researchers at the University of Pittsburgh have linked the female hormone with non-small cell lung cancer. Lung cancer kills more women (about 60,000 annually) than any other type of cancer. Eighty percent of the cases involve non-small cell tumors. Research suggests women develop the disease younger and with less tobacco use than men. The types of tumors and the molecular mechanisms underlying lung cancer differ in women and men. The Pittsburgh team, looking for the reasons behind the data, previously discovered that a gene known to fuel lung cancer growth is more active in women than in men.
Their current research showed that normal lung tissue rarely contained measurable levels of the estrogen receptor ER alpha, but lung cancer specimens had significant quantities. "In our studies, we found greater numbers of estrogen receptors on lung cancer cells than on normal lung cells, strongly suggesting a role for this hormone in enhancing tumor growth," said principle investigator Jill Siegfried, Ph.D., at the University of Pittsburgh. "Women have a naturally higher circulating estrogen level than men, and this difference may contribute to their increased susceptibility to lung cancer."
The researchers also saw more cell division in cultured lung cancer cells treated with estrogen, and animals with human lung cancers receiving estrogen experienced increased tumor growth. Administering antiestrogens blocked the development of cancer. Halting estrogen's effects could become a tool in preventing recurrence or stopping lung cancer progression in women. "In addition, blocking estrogen receptors could prove beneficial in preventing lung cancer in women at high risk, much like blocking estrogen's effect has been shown to prevent breast cancer in women at increased risk for that disease," said Siegfried, who presented the study's results at the annual meeting of the American Association for Cancer Research.
April 4, 2000
High blood pressure drugs put patients at added risk for diabetes
High blood pressure and treatment with a specific class of drugs to control it increase patients' risk of developing Type 2, adult onset, diabetes mellitus according to a report in the New England Journal of Medicine.
The prospective, nationwide study led by researchers at Johns Hopkins included 12,550 adults between 45 and 64 years of age who had heart disease or were at risk for it but did not have diabetes. At the start of the study, the team found 3,804 participants had hypertension and determined medication use. The team evaluated blood sugar levels after three and six years. At the end of the study, 1,146 people had developed diabetes, almost an equal number of people with and without hypertension, even though those with high blood pressure comprised less than a third of the participants.
The scientists adjusted for demographics, education, a family history of diabetes and coexisting illnesses, and found that people with hypertension who were taking beta blockers to control the condition were 28 percent more likely to develop diabetes than those not taking drugs. Patients with hypertension taking thiazide diuretics, angiotensin-converting-enzyme inhibitors and calcium-channel antagonists were not at greater risk than people with high blood pressure who were not taking any medication. Patients should not stop taking their drugs based on the results of this study. "We're not suggesting that doctors stop prescribing beta blockers, as they have proven benefits in lowering the risk of cardiac events," said Dr. Frederick L. Brancati, at Johns Hopkins. "But physicians need to weigh the benefits against the diabetes risk and monitor patients carefully. Physicians also should not be discouraged from prescribing thiazide diuretics, as our study did not find a causal link to diabetes. These are good medications to prevent heart disease and stroke."
April 3, 2000
Gene allows common virus to trigger heart failure
Canadian researchers have discovered a gene that lets a highly contagious, common virus attack the heart. They predict their findings will lead to new cardiac treatment strategies. The key gene, called p56Ick, allows Coxsackievirus B, a virus found in human digestive systems, to cause heart failure and death in some people. The virus can be found in the hearts of about 30 to 50 percent of adults suffering from heart failure and may be responsible for more than 12 percent of heart failure cases. "This finding could lead to a much more targeted way to determine who is at very high risk for developing heart disease," said senior author Dr. Josef Penninger, an immunologist at Princess Margaret Hospital's Ontario Cancer Institute. "Rather than guessing at potential risk factors, we will be able to say much more definitively who's likely to get heart disease by testing for the presence of one gene."
About 70 percent of the population has been exposed to Coxsackievirus B, which can cause anything from flu-like symptoms to pancreatitis, arthritis, meningitis and myocarditis. No vaccines and no cures exist. Researchers learned that the p56Ick gene determines if a minor illness occurs or heart disease. When mice with the gene were injected with the virus they developed severe inflammation and died of heart failure, while mice without the gene exhibited no signs of heart disease, even after exposure to large doses.
"Nearly all of us have been exposed to Coxsackievirus B at some time in our lives and experienced nothing more than the flu," said lead author Dr. Peter Liu, a cardiologist at Toronto General Hospital. "However, in those people at risk, the p56Ick gene helps the virus to trigger the immune system to turn against the heart muscle. Without the p56Ick gene, the virus cannot replicate and remains relatively harmless."
April 3, 2000
Genetic changes may cause most age-related diseases
Many and perhaps all age-related illnesses, including arthritis, osteoporosis and Alzheimer's disease, may result from gradual genetic changes, according to a study published in the journal Science. Researchers at The Skaggs Institute for Chemical Biology at The Scripps Research Institute in California and Genomics Institute of the Novartis Research Foundation reported that cell division errors begin in middle age and gradually increase as years pass. Errors in key genes led to functional loss. The team found that age-related genetic dysfunction occurs in a mosaic pattern and at different rates depending on the body part. "This represents a radical change in the way people have thought about aging. While scientists have believed that aging is a disease in which cells stop dividing, this study suggests that aging is really a disease of quality control. In this case the manufactured product is a new cell. As we get older, altered gene expression results in cells with diminished function," said author Dr. Richard A. Lerner at The Skaggs Institute. "Our research ties the effects of aging into a single package by identifying a common element in aging tissues throughout the body."
Using cells donated from young, middle-aged and older people, and patients with the accelerated-aging disease progeria, the team assessed gene regulation in cells that were actively dividing and found 61 of the 6,000 genes had consistent changes. The study also noted genes that had altered expression may contribute to age-related breast cancer, neurogenerative disease, Alzheimer's, arthritis, and kidney, heart and ovary problems.
"We need broader analyses of how genes function, how they interact with one another and with the environment. This research will bring us closer to identifying specific genes associated with age-related diseases and potential ways to prevent and/or treat them," Lerner said.
April 3, 2000
Device helps surgeons detect cancer
A dime-sized device developed by scientists at the U.S. Department of Energy's Sandia National Laboratories can alert surgeons to the location of cancer cells during surgery, helping them more accurately remove tumors without cutting away more healthy tissue than necessary. Not removing excess tissue in the brain can minimize complications and postoperative deficits. The prototype biological microcavity laser, also known as the biocavity laser, was able to accurately distinguish between cultures of normal brain cells and malignant cells during laboratory testing.
"We can quickly identify a cell population that has abnormal protein content, as do tumor cells, by passing only a few hundred cells -- a billionth of a liter -- through our device," said Paul Gourley, leader of the Sandia effort. The Department of Energy selected the research as the Best Project of the Year in the Basic Energy Sciences division during a competition involving 28 labs.
As the surgeon cuts, an aspirator vacuums blood from the incision into the microcavity laser contained in the scalpel's handle. The microlaser beam enters the cells. Cancer cells contain more protein than normal cells and refract the speed of the laser light differently. The biocavity laser captures this difference in output frequency and transmits it by optical fiber to a nearby laptop computer. The data is translated into graph form and continually changes as the surgeon moves the device. The doctor, reading the peaks and valleys on the graph, knows when the blood from the incision is free of cancer cells. The biocavity laser will cost between $10,000 to $50,000 and can analyze of up to 100,000 cells per second. Currently, to tell if a cell is cancerous, the sample must be stained and examined by a highly trained operator with a $100,000 flow cell cytometer, which may take hours.
April 3, 2000
Polymer offers hope for drug-resistant ovarian cancer
Researchers at Florida Atlantic University in Boca Raton have developed a new polymer-drug combination using a commonly ordered antibiotic, and dramatically stopped the growth of ovarian cancer cell lines that the scientists thought were resistant to drugs. Polymers are compounds formed by joining two or more lighter molecules of the same type. The scientists modified the antibiotic cephalexin with a tin polymer. The antibiotic is not effective against cancer, and researchers are not sure why the polymer works. They said it appears to be a synergistic effect from the metal. The team is now testing combinations of cephalexin and polymers containing arsenic, alimony and bismuth. "When you make polymers without the metals, as far as we can tell, you don't get much activity," said Charles Carraher, Ph.D.
The cell lines came from ovarian cancer patients who had received conventional chemotherapy. The new polymer drug blocked growth of one cancer cell line by 97 percent and another by 80 percent. The team presented the findings at a meeting of the American Chemical Society. Carraher considers the results promising and says the new polymer offers potential as a last defense cancer drug. However, he also cautions that there are no miracle cures and additional testing with animals is needed.
The American Cancer Society predicts 14,000 women will die of ovarian cancer this year. Ovarian cancer kills more women than any other female reproductive cancer. The disease has a five year survival rate of 50 percent and a one year survival rate of 78 percent. Rates increase if the disease is found and treated early, but obvious symptoms are rare until late in the disease's progression. Only 25 percent of an estimated 23,100 new cases per year are detected while the cancer is still localized.
April 3, 2000
New H. pylori test for ulcers
Almost 20 years ago, doctors discovered that the bacteria H. pylori caused many peptic ulcers, but accurate methods for determining if an active infection existed remained more elusive. Existing blood tests could only check for antibodies, which continue to show up after the infection has been cleared. Urea breath tests were primarily used after treatment to determine if it was successful. Tissue samples for culturing and other testing had to be collected with the patient sedated, using an endoscope threaded down the patient's throat.
Now a simple blood test developed by Boston University and recently approved by the Food and Drug Administration can show if there is an active H. pylori infection. The test will be marketed under the name Ez-HBT(tm) by Metabolic Solutions Inc. The patient ingests a small dose of 13C-urea. If H. Pylori is present, the bacterial enzyme urease converts the urea to 13CO2, a type of carbon dioxide, and ammonia. The 13CO2 is absorbed into the bloodstream. Half an hour later, personnel at the doctor's office draw a blood sample and send it to a laboratory for analysis of the 13CO2 level using an isotope ratio mass spectrometer. If 13CO2 is present, the test indicates an H. pylori infection and the doctor can order antibiotics to kill the bacteria, as well as drugs to protect the stomach lining and decrease the amount of acid. The complicated regimen of three different medications and resulting side effects makes it difficult for some patients to precisely follow. Doctors also can use the new Ez-HBT test to determine if the treatment killed all the bacteria.
It is still unclear how people become infected with H. pylori, but researchers expect it may occur through ingestion of food or water or, because the bacteria has been found in saliva, from kissing or other mouth to mouth contact.
April 3, 2000
Researchers find mechanism behind penicillin resistance
Found in hospitals and the community, penicillin-resistant bacteria make treating infections more difficult. Bacteria resistant to antibiotics play a role in almost all hospital acquired infections. Widespread and inappropriate use of antibiotics contribute to the problem. Researchers have now discovered how beta-lactamase, an enzyme produced by resistant bacteria, deactivates penicillin. The scientists expect that knowledge will lead to development of superior antibiotics.
In a study published in the journal Proceedings of the National Academy of Sciences, researchers analyzed penicillin and b-lactamase enzyme atoms and their electrostatic forces. The scientists produced a computer simulation of the atoms' interaction and found that b-lactamase attacks penicillin differently than expected. The penicillin molecule includes a b-lactam ring segment. If a bond in the ring is destroyed the drug becomes ineffective. The Chicago team found that b-lactamase adds a proton to the bond, rendering it unstable, so the bond breaks more easily. "While we cannot predict how these results may lead to improved antibiotics, the chemical principles governing the reactivity of penicillin that we have found are fundamental for designing compounds of pharmacologic importance," said Marvin W. Makinen, Ph.D., at the University of Chicago. "Knowing more accurately the chemical and physical basis of the interaction of penicillin and b-lactamases will help in structure-based drug design."
April 3, 2000
Vitamins C and E offer protection against vascular dementia
Older patients who took supplements of antioxidant vitamins boosted their mental ability and received protection against some forms of dementia, during a University of Hawaii study published in the journal Neurology. "We believe antioxidants like vitamin E and C may protect against vascular dementia by limiting the amount of brain damage that persists after a stroke," said study author Dr. Kamal Masaki. "The supplements may also play a role in providing protection against brain cell and membrane injury involved in many aging-related diseases, thus resulting in significantly higher scores on mental performance tests in later life."
The researchers examined 3,385 Japanese-American men participating in the Honolulu Heart Program, which began in 1965 to study heart disease and stroke. The team assessed the 71 to 93 year old men for signs of dementia and mental abilities. After four years, patients taking vitamins E and C supplements, at least weekly, were 88 percent less likely to have vascular dementia and 69 percent less likely to have other forms of dementia. The team found no reduction in Alzheimer's disease. "We originally thought that the beneficial impact antioxidant vitamin supplements had against vascular dementia was the prevention of stroke," commented Masaki. "However, to our surprise, we found there was not a significant association between vitamin supplement use and clinically recognized stroke."
Patients who did not have dementia and took the vitamins regularly during a three to five year period had a 20 percent chance of performing better on mental function exams than men not taking supplements. But those men taking supplements for an additional six years had about a 75 percent greater chance of better cognitive performance than those not taking the vitamins, suggesting long-term use can significantly improve mental functioning later in life.
April 1, 2000
Glaucoma affects more than the eyes
Glaucoma can silently steal a person's eyesight, but now researchers say the degenerative disease causes more than the death of nerve cells at the back of the eye. A team from the University of Toronto and St. Michael's Hospital found that glaucoma affects the entire visual system, which includes the brain.
Normally nerve cells in the eye send signals via the optic nerve to other nerve cells in the brain called target neurons. The eye, in return, receives essential growth factors from nerve cells in the brain. Glaucoma causes pressure to build in the eye, which damages nerves and leads to blindness. Doctors treat the disease with eye drops or surgery to decrease the pressure.
The team used three dimensional computer reconstruction to help them count the number of nerve cells in tissue from the eye and corresponding visual cortex of the brain of monkeys with experimentally induced glaucoma and from healthy animals. Forty percent of the eye and brain nerve cells were damaged in tissue from those with glaucoma. Greater losses were observed in animals with moderate to advanced disease. "Our study shows for the first time that in glaucoma there is also a loss of specific nerve cells in the brain which control our ability to see color and motion," said lead author Dr. Yeni Yucel, of the study published in Archives of Ophthalmology. "The concept that glaucoma is a neurodegenerative disease affecting also the major vision centers in the brain is a major breakthrough in the understanding of this disease."
Future research is planned to determine what causes the nerve cells to die, in order to develop strategies to prevent it from happening. About 3 million Americans and 67 million people worldwide suffer from glaucoma, a leading cause of blindness.
April 1, 2000
Unexplained foot fractures indicate osteoporosis
Breaking a foot bone while walking may serve as a warning for osteoporosis, according to researchers at Ohio State University. The team found that 20 out of 21 men and women who had metatarsal fractures from an unknown cause had early signs of osteoporosis. The fractures could not be attributed to overuse, strenuous exercise, kicking or trauma to the area. "Each foot fracture had been caused by normal weight bearing. Some patients were walking when they felt their bones break," said coauthor Rodney Tomczak, who presented the findings at the annual meeting of the American College of Foot and Ankle Surgeons. "We found a correlation between these unexplained foot fractures and low bone density, one of the primary symptoms of osteoporosis."
All six men studied, whose average age was 35, had low bone densities, as did 14 of the women, with an average age of 54. Older women are typically considered at higher risk for osteoporosis. But all the men in the study and most of the women had medical conditions that increased their chances of developing the disease. Kidney failure, insulin-dependent diabetes, menopause and low testosterone levels can contribute to low bone densities.
A foot fracture without an apparent cause does not always indicate the patient has osteoporosis, but it should alert doctors to the possibility. "Only through bone density testing can an early diagnosis of osteoporosis be made," Tomczak said. "Podiatrists should carefully inspect their patients who may be at risk for developing osteoporosis. The first manifestation of osteoporosis in many people is an unexplained foot fracture."
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