Among patients with a family or past history of colorectal cancer (CRC), testing between colonoscopies helps detect CRC and advanced tumors that are either missed or develop rapidly, according to a new study in Gastroenterology, the official journal of the American Gastroenterological Association (AGA) Institute.
"By using fecal immunochemical testing - a new type of stool blood test - in the interval between surveillance colonoscopies, we were able to detect cancer much sooner than if we had waited for the scheduled surveillance," said Graeme P. Young, MD, AGAF, FRACP, of Flinders Medical Centre, Australia and lead author of the study. "In fact, in those patients who consistently returned a negative fecal immunochemical test, the chance of finding cancer or advanced adenoma was significantly reduced."
A joint guideline from the American Cancer Society, the U.S. Multi-Society Task Force on Colorectal Cancer and the American College of Radiology recommends that average-risk adults, beginning at the age of 50, should receive a colonoscopy every ten years and that annual fecal immunochemical tests (FIT) are acceptable choices for CRC screening in between this ten-year span (any positive FIT should be followed up with a colonoscopy).1 Guidelines suggest more frequent colonoscopies for certain high-risk groups.
In this study, 1,736 patients with a confirmed family or personal history of CRC were followed for 8,863 person years of surveillance; some for as long as 20 years. The study inclusion criteria required that patients had received at least an initial and one subsequent surveillance colonoscopy with adequate examination and retrieval of tissue, performed with a training-accredited colonoscopist present. In the 1,071 asymptomatic subjects who returned at least one FIT after the colonoscopies, the test detected 12 out of 14 cancers and 60 out of 96 advanced adenomas. In FIT-positive cases, the diagnosis was made sooner by 25 months for cancer and by 24 months for advanced adenomas before the regularly scheduled colonoscopy.
"Our study results suggest that interval fecal immunochemical testing in a high-risk colonoscopy program can be used for detecting missed or rapidly developing lesions," added Dr. Young.
Patients at increased risk for developing CRC due to a family history or past history of CRC are recommended to have colonoscopic surveillance at regular intervals, often more frequently than recommended for the average-risk population. Patients with only one or two small adenomas with low-grade dysplasia are recommended to have their second surveillance colonoscopy after an interval of 10 years. However, for these individuals, there is a greater risk of delay in detecting rapidly progressing or missed lesions. Using annual fecal occult blood tests in the interval between surveillance colonoscopies could be a strategy that helps manage this risk. FIT, which uses an antibody specific for human hemoglobin, is being increasingly used because it is more sensitive for cancer and adenomas.
To learn more about CRC and FIT, visit the patient center on the AGA website at http://www.gastro.org/patient-center.
1. Levin B., Lieberman DA., McFarland B. et al. Screening and Surveillance for the Early Detection of Colorectal Cancer and Adenomatous Polyps, 2008: A Joint Guideline From the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. Gastroenterology 2008 May;134(5):1570-95.
Researchers reverse stroke damage by jumpstarting nerve fibers
MAYWOOD, Ill. - A new technique that jumpstarts the growth of nerve fibers could reverse much of the damage caused by strokes, researchers report in the Jan. 7, 2011 issue of the journal Stroke.
"This therapy may be used to restore function even when it's given long after ischemic brain damage has occurred," senior author Gwendolyn Kartje, MD, PhD and colleagues write.
The article has been published online in advance of the print edition of Stroke. Kartje is director of the Neuroscience Institute of Loyola University Chicago Stritch School of Medicine and chief of neuroscience research at Edward Hines Jr. VA Hospital.
There currently is little doctors can do to limit stroke damage after the first day following a stroke. Most strokes are ischemic (caused by blood clots). A drug called tPA can limit damage, but must be given within the first three hours for the greatest benefit - and most patients do not receive treatment within that time window.
Kartje and colleagues report on a treatment called anti-Nogo-A therapy. Nogo-A is a protein that inhibits the growth of nerve fibers called axons. It serves as a check on runaway nerve growth that could cause a patient to be overly sensitive to pain, or to experience involuntary movements. (The protein is called Nogo because it in effect says "No go" to axons.) In anti-Nogo therapy, an antibody disables the Nogo protein. This allows the growth of axons into the stroke-affected side of the body and the restoration of functions lost due to stroke.
Kartje and colleagues report dramatic results of anti-Nogo therapy in rats that had experienced medically induced strokes. Researchers trained rats to reach and grab food pellets with their front paws. One week after experiencing a stroke, the animals all had significant deficits in grabbing pellets with their stroke-impaired limbs. There was little improvement over the next eight weeks.
Nine weeks after their stroke, six rats received anti-Nogo therapy, four rats received a control treatment consisting of an inactive antibody and five rats received no treatment. Nine weeks later, rats that had received anti-Nogo therapy regained 78 percent of their pre-stroke ability to grab pellets. By comparison, rats receiving no treatment regained 47 percent of their pre-stroke ability, and rats receiving the control treatment of inactive antibodies regained 33 percent of their pre-stroke performance. Subsequent examination of brain tissue found that the rats that received anti-Nogo therapy experienced significant sprouting of axons.
Researchers wrote that anti-nogo therapy "can induce remarkable compensatory sprouting and fiber growth, indicating the responsiveness of the chronically injured brain to form new neural networks under the proper growth conditions."
The findings "are of great clinical importance," researchers concluded. Anti-Nogo-A therapy "may benefit not only victims of spinal cord injury or patients in the early stage of stroke recovery, but also patients in later stages who suffer from neurological disability due to brain damage from stroke or other causes."
In a Phase I, multicenter trail at other centers, patients paralyzed by spinal cord injuries are receiving anti-Nogo therapy. The trial is sponsored by the pharmaceutical company Novartis.
Kartje's co-authors of the study in Stroke are first author Shih-Yen Tsai, MD, PhD and Catherine Papadopoulos, PhD, of Hines VA Hospital and Martin Schwab, PhD, of the University of Zurich.
The study was funded by the Department of Veterans Affairs and the National Institute of Neurological Disorders and Stroke.
Desensitisation approaches effective against hayfever-like allergies
Immunotherapy given as pills or drops under the tongue is a safe and effective way to treat hayfever-like allergies caused by pollen and dust mites, according to a new Cochrane Systematic Review.
The researchers say the approach is an attractive alternative to immunotherapy injections in children.
Common treatments for hayfever-like symptoms caused by allergies include antihistamines and nasal corticosteroids. If these prove unsuccessful, doctors may recommend immunotherapy, a desensitisation approach that involves exposing patients to increasing doses of an allergen. Traditionally immunotherapy was carried out by injection, but allergens are now also applied as pills or drops under the tongue.
Although a 2003 Cochrane review suggested sublingual immunotherapy was effective, the findings were based on a relatively small number of trials. Much more evidence is now available and the researchers were able to add another 38 studies to their current review, totalling 60 altogether. They included trials of pollen and dust mites, as well as one trial of cat allergens. Sublingual immunotherapy significantly reduced symptoms of allergic rhinitis and requirements for medication compared to placebos. The results confirm the treatment is effective and has very few serious adverse effects.
The larger number of trials allowed the researchers to make stronger recommendations for use of sublingual immunotherapy in children. "This is an attractive approach for treating allergies in children. It is a more convenient alternative compared to injection immunotherapy," said Suzana Radulovic, one of the review authors, who is currently based at the Paediatric Allergy Research Department at St Thomas' Hospital in London, UK. "It is encouraging to see similar treatment effects in children compared to those in adults."
Overall, treatment effects comparable to those seen in the previous review provide greater reassurance for clinical practitioners. "Sublingual immunotherapy is an effective treatment for allergic rhinitis. With the inclusion of larger, better designed trials, we can be much more confident about the results," said Radulovic. "What we'd like to see now is more work on optimum dosage and treatment times."
Washington, D.C. - You've seen it in movies: the human-like, robot assassin quickly regenerates its structure after being damaged beyond recognition. This "Terminator" scenario is becoming less far-fetched as recent advances in structural health monitoring systems have led to a variety of ways to identify damage to a structural system.
Now, in the Journal of Applied Physics, researchers at Arizona State University have created a material that may be able to not only sense damage in structural materials, such as cracking in a fiber-reinforced composite, but to even heal it. The aim of developing "autonomous adaptive structures" is to mimic the ability of biological systems such as bone to sense the presence of damage, halt its progression, and regenerate itself.
The novel autonomous material developed by Henry Sodano and colleagues uses "shape-memory" polymers with an embedded fiber-optic network that functions as both the damage detection sensor and thermal stimulus delivery system to produce a response that mimics the advanced sensory and healing traits shown in biological systems. An infrared laser transmits light through the fiber-optic system to locally heat the material, stimulating the toughening and healing mechanisms.
The material system is capable of increasing the toughness of a specimen by 11 times. After toughening the specimen, the crack can be closed using the shape-memory effect to recover an unprecedented 96 percent of the object's original strength. In fact, after the crack is closed, the new material is nearly five times as tough as the original specimen, even though it has been strained past its original failure strain point by a factor of four. The material and healing process can be applied while the structure is in operation, which has not been possible with existing healing techniques.
The article, "Autonomous Materials with Controlled Toughening and Healing" by Michael Garcia, Yirong Lin, and Henry Angelo Sodano appears in the Journal of Applied Physics. See: http://link.aip.org/link/japiau/v108/i9/p093512/s1
Studies highlight need for new antiviral treatment options and strategies
Two new studies raise public health concerns about increasing antiviral resistance among certain influenza viruses, their ability to spread, and a lack of alternative antiviral treatment options. The findings are published in the January 1 issue of The Journal of Infectious Diseases. (Please see below for links to these articles online.)
Influenza viruses are treated with two classes of drugs: M2 blockers (adamantanes) and neuraminidase inhibitors (NAIs), including oseltamivir and zanamivir. While the spread of influenza strains with resistance to one class of drugs has been well documented in recent years, a new report from Larisa Gubareva, MD, PhD and colleagues at the Centers for Disease Control and Prevention (CDC) and at health agencies in West Virginia, Texas, and Canada, confirms that dual resistance can emerge in several ways and has been on the rise during the past three years.
The study analyzed 28 seasonal H1N1 viruses with dual resistance from 2008 to 2010 from five countries, revealing that additional antiviral resistance could rapidly develop in a previously single-resistant strain as a result of mutation, drug response, or gene exchange with another virus.
Although dual resistant viruses are still rare, the investigators noted an increase in the number of tested viruses with this resistance, from 0.06 percent (2007-2008) to 1.5 percent (2008-2009) to 28 percent (2009-2010); however, during the 2009-2010 season the number of circulating seasonal H1N1 viruses was low, and only 25 viruses were tested. "Because only two classes of antiviral agents are approved, the detection of viruses with resistance to drugs in both classes is concerning," said Dr. Gubareva. "If circulation of viruses with dual resistance becomes more widespread among any of the predominant circulating influenza A viruses, treatment options will be extremely limited. New antiviral agents and strategies for antiviral therapy are likely to be necessary in the future."
A second study, conducted by Catherine Moore and colleagues in the United Kingdom, examined an outbreak of oseltamivir resistant (OR) pandemic H1N1 infection in a hematology unit in the UK. The study is the first to confirm person-to-person transmission of this dually resistant strain through molecular epidemiologic methods. The 2009 pandemic H1N1 virus was inherently resistant to adamantine, but was susceptible to and treated with oseltamivir. However, by October 2009, emergence of OR H1N1 had been documented in rare patients on oseltamivir therapy.
In the hematology unit that Moore and colleagues studied, eight of the 11 pandemic H1N1 virus infections were resistant to oseltamivir, with half of those cases resulting from direct transmission of the resistant virus. Immunocompromised patients were more susceptible to the emergence of OR H1N1 virus on treatment and also transmitted the virus to others, despite often having no influenza symptoms or having completed antiviral therapy. As a result, the screening of patients for OR H1N1 viruses became particularly important, and treatment guidelines were altered to include treatment with zanamivir, to which the viruses remained susceptible.
"These findings suggest that oseltamivir may not be the frontline drug of choice in hematology patients, and zanamivir may prove to be more beneficial," the study authors wrote. "Guidelines may need to be changed to include active screening for the [OR] mutation in hematology patients diagnosed with H1N1 and other patients who are immunocompromised when oseltamivir is used." If high risk groups are more actively monitored, early diagnosis will help prevent the spread of H1N1 viruses, and proper screening for infection and resistance will aid in making proper therapeutic decisions.
In an accompanying editorial, Frederick G. Hayden, MD, of the University of Virginia School of Medicine, and Menno D. de Jong, MD, of the University of Amsterdam in the Netherlands, agreed that increasingly detailed monitoring and creative preventive and therapeutic choices will be required as unpredictable and antiviral-resistant influenza viruses continue to appear. This is especially true "given our current paucity of therapeutic choices," according to the authors. With only two drug classes approved in the U.S. and most countries for treating influenza virus, future research should focus on the effectiveness of zanamivir and combination antiviral therapy and the need to develop new antivirals with unique mechanisms of action.
"Such information will ensure rapid development and testing of alternative antiviral strategies for use in immunocompromised hosts and seriously ill hospitalized patients to address their unmet medical needs and the associated public health concerns, particularly the continuing threat of antiviral resistance," the authors conclude.
The studies and the accompanying editorial are available online. They are embargoed until 2 p.m. EST on Tuesday, Dec. 7, 2010: "Dual Resistance to Adamantanes and Oseltamivir Among Seasonal Influenza A (H1N1) Viruses: 2008-2010"
A giant marabou stork has been discovered on an island once home to human-like 'hobbits'.
Fossils of the bird were discovered on the Indonesian island of Flores, a place previously famed for the discovery of Homo floresiensis, a small hominin species closely related to modern humans. The stork may have been capable of hunting and eating juvenile members of this hominin species, say researchers who made the discovery, though there is no direct evidence the birds did so. The finding, reported in the Zoological Journal of the Linnean Society, also helps explain how prehistoric wildlife adapted to living on islands.