Risk of cancer due to radiation exposure in middle age higher

An interesting analysis of  A-bomb survivor data published in the  Journal of the National Cancer Institute  ( 25 October 2010) revealed that  contrary to common assumptions, the risk of cancer associated with radiation exposure in middle age may not be lower than the risk associated with exposure at younger ages. Children are more sensitive than adults to the effects of radiation and that they have a greater risk of developing radiation-induced cancer than adults. Some data also suggest that, in general, the older a person is when exposed to radiation, the lower their risk of developing a radiation-induced cancer.

Recent analysis of the statistical evidence from long-term studies of atomic bomb survivors in Japan indicates that for radiation exposure after about age 30, the risk of developing radiation-induced cancer does not continue to dec

David J. Brenner, Ph.D., D.Sc., at Columbia University in New York, and colleagues reanalyzed the Japanese atomic bomb survivor data assuming two different pathways through which radiation exposure can ultimately lead to cancer. The first is initiation of gene mutations that convert normal stem cells to premalignant cells that could eventually lead to cancer. The second is radiation induced promotion, or expansion, of the number of existing premalignant cells in the body. The initiation effect is more likely to play a role in children than in adults, they reason, because cells initiated at an early age have a longer time available to expand in number and progress on the pathway to cancer. The promotion effect, on the other hand, is more likely to be important for radiation exposures in middle age, because the adult body already contains larger numbers of premalignant cells.
The researchers developed a model based on these biological effects and applied the model to the Japanese atomic bomb survivor data. They found that the model was able to reproduce the cancer risk patterns associated with age at radiation exposure observed in these survivors. They then applied the same model to predict cancer risks as a function of age in the U.S. population and found that the cancer risks predicted by the model were consistent with the data in the age range from about 30 to 60.

The authors conclude that cancer risk after exposure in middle age may increase for some tumor types contrary to conventional wisdom. They add that these findings could have practical implications regarding x-ray diagnostic tests, which are predominantly performed on middle aged adults, as well as for occupations that involve radiation exposures, again where most exposures are in middle age.

"Overall, the weight of the epidemiological evidence suggests that for adult exposures, radiation risks do not generally decrease with increasing age at exposure," they write, "and the mechanistic underpinning described here provides this conclusion with some biological plausibility."

In an accompanying editorial, John D. Boice, Sc.D., of the International Epidemiology Institute, Rockville, Md., and Vanderbilt University, Nashville, cautioned that there are uncertainties in generalizing the Japanese data to a U.S. population. He also notes that other data and other models contradict the results of this study. However, he concludes that this biology-based model "raises provocative hypotheses and conclusions that, although preliminary, draw attention to the continued importance of low-dose radiation exposures in our society."

Dr Brenner often comes up with papers which may appear controversial; but they are based on a deep understanding of the biological mechanisms of cancer induction. In 2005 he along with some of the most eminent radio-biologists and epidemiologists known internationally  reviewed the status of low dose radiation risk. The paper was stoutly criticized by many because of its over dependence on the Linear No n Threshold concep.

Though not the ideal data A-bomb survivor data continue to dominate the study of radiation risk

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The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute

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Viral and fungal infection kill bees by the billions

Some people have attributed the collapse of bees by their billions to mobile phone radiation. None of these observations were based on any scientific study. These "researchers" produced sensational reports and published them mostly in daily newspaper. Colony Collapse Syndrome has bees seen in many countries.Such collapse can have a devastating impact on food production as bees are efficient pollinators
 
The sudden death of bee colonies since late 2006 across North America has stumped scientists. But today, researchers may have a greater understanding of the mysterious colony collapse disorder, said a Texas Tech University biologist.

Shan Bilimoria, a professor and molecular virologist, said the bees may be taking a one-two punch from both an insect virus and a fungus, which may be causing bees to die off by the billions.

Bilimoria is part of a team of researchers searching for the cause of the collapse. Led by research professor Jerry Bromenshenk from the University of Montana in Missoula, the group also includes virologists and chemists from the U.S. Army Edgewood Chemical Biological Center and the Instituto de Ecologica AC in Mexico.

Their study was published this week in the peer-reviewed journal PLoS ONE.

"At this stage, the study is showing an association of death rates of the bees with the virus and fungus present," Bilimoria said. "Our contribution to this study confirms association. But even that doesn't prove cause and effect. Not just yet."

The mysterious colony deaths have caused major concern with scientists since much of agriculture depends on bees to pollinate crops.

To discover what might be attacking bee colonies, the team ground up dead bees that had succumbed to colony collapse disorder. Using analytical equipment, researchers discovered through spectroscopic analysis evidence of a moth virus called insect iridescent virus (IIV) 6 and a fungal parasite called Nosema.
The insect virus is closely related to another virus that wiped out bee populations 20 years ago in India, he said. Also, unlike previous research that found the deaths may be caused by a virus with RNA, the IIV 6 contains DNA.

"Our DNA discovery puts this field in a whole new direction," he said.

Bilimoria said Texas Tech supplied the virus material for the experiments and were tested on bees with the fungus. Though an association between exposure and death was found, scientists don't yet know if the two pathogens cause CCD or whether CCD colonies are more likely to succumb to the two pathogens.
"To prove cause and effect, we will have to isolate the virus and fungus from bee colony, and then reinfect with same virus and fungus," Bilimoria said.
In the next part of the research project, Bilimoria will work to isolate the virus from infected bees.
"Once we isolate and identify the virus, we will have a way of monitoring it," he said. "It is easier to fight the problem if we know what the culprit is."

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Transgenic corn helps all farmers; saves billions in USA

In India , introduction of transgenic crops is mired in controversy. Probably popular apprehensions  and now plagiarism come in the way of exploiting the technology. The story coming from the USA will be of interest to the discerning Indian farmer.Last year 63% of the corn cultivated in USA was transgenic.Recently non Bt corn farmers have got benefits.

		IMAGE: Transgenic corn's suppression of the European corn borer has saved Midwest farmers billions of dollars in the past decade, reports a new study in Science. Click here for more information.

Transgenic corn's suppression of the European corn borer has saved Midwest farmers billions of dollars in the past decade, reports a new study in the October 8 edition of Science.
Studies carried out several Midwest universities show that suppression of this pest has saved $3.2 billion for corn growers in Illinois, Minnesota, and Wisconsin over the past 14 years with more than $2.4 billion of this total benefiting non-Bt corn growers. Comparable estimates for Iowa and Nebraska are $3.6 billion in total, with $1.9 billion accruing for non-Bt corn growers.
Transgenic corn is engineered to express insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). Bt corn has become widely adopted in U.S. agriculture since its commercialization in 1996.

The truly secular behaviour of  female corn borer moths hurts them incalculably. They can't distinguish between Bt and non-Bt corn, so females lay eggs in both types of fields. Once eggs hatch in Bt corn, young borer larvae feed and die within 24 to 48 hours.
The major benefit of planting Bt corn is reduced yield losses, and Bt acres received this benefit after the growers paid Bt corn technology fees. But as a result of areawide pest suppression, non-Bt acres also experienced yield savings free, without the cost of Bt technology fees, and thus received more than half of the benefits from growing Bt corn in the region.
"We've assumed for some time that economic benefits were accruing, even among producers who opted not to plant Bt hybrids," said co-author of the study Mike Gray, University of Illinois Extension entomologist and professor in the Department of Crop Sciences. "However, once quantified, the magnitude of this benefit was even more impressive."
Over the past several years, entomologists and corn producers have noticed very low densities of European corn borers in Illinois. In fact, Illinois densities have reached historic lows to the point where many are questioning its pest status, Gray said.
"Since the introduction of Bt corn, initially targeted primarily at the European corn borer, many entomologists and ecologists have wondered if population suppression over a large area would eventually occur," Gray said. "As this research shows, area wide suppression has occurred and dramatically reduced the estimated $1 billion in annual losses caused previously by the European corn borer."
This information also provides incentives for growers to plant non-Bt corn in addition to Bt corn.
"Sustained economic and environmental benefits of this technology will depend on continued stewardship by producers to maintain non-Bt maize refuges to minimize the risk of evolution of Bt resistance in crop pest species," Gray said.

Cheek swab may detect lung cancer

 
In clinical trial, technique appears to detect lung cancer far afield from a tumor

		IMAGE: Nano-scale disturbances in cheek cells indicate the presence of lung cancer. Regular microscopy looking at chromatin, the genetic material inside a cell's nucleus, will not reveal significant dissimilarities between the... Click here for more information.

Early detection is critical for improving cancer survival rates. Yet, lung cancer, one of the deadliest cancers in the United States, is notoriously difficult to detect in its early stages.
Now, the US National Science Foundation  supported researchers have developed a method to detect lung cancer by merely shining diffuse light on cells swabbed from patients' cheeks.
Recently, in a new clinical study, the analysis technique--called partial wave spectroscopic (PWS) microscopy--was able to differentiate individuals with lung cancer from those without, even if the non-cancerous patients had been lifetime smokers or suffered from chronic obstructive pulmonary disease (COPD).
The findings-released by a team of engineers and physicians from NorthShore University Health System, Northwestern University and New York University-appear in print in the Oct. 15, 2010, issue of the journal Cancer Research.
"This study is important because it provides the proof of concept that a minimally intrusive, risk-stratification technique may allow us to tailor screening for lung cancer, the leading cause of cancer deaths in Americans," said physician and researcher Hemant Roy of NorthShore University HealthSystems and the University of Chicago, the lead author on the paper. "This represents a major step forward in translating biomedical optics breakthroughs for personalized screening for lung cancer."
The recent results are an extension of several successful trials involving the light-scattering analysis technique, including early detection successes with pancreatic cancer and colon cancer. NSF has supported the team's work since 2002, with an early grant to Roy's collaborator and co-author, bioengineer Vadim Backman of Northwestern University.
"Their work has now transitioned to a larger $2 million Emerging Frontiers in Research and Innovation award," said Leon Esterowitz, a biophotonics expert and program director at NSF who has long supported the research. "The results have even larger implications in that the techniques and the 'field effect' may be a general phenomena that could be applied to a multitude of epithelial cancers, the most common cancer type."
The continuing clinical and laboratory experiments involving the PWS light-scattering technique-and its predecessor technologies, four-dimensional elastic light scattering fingerprinting (4D-ELF) and low-coherence enhanced backscattering spectroscopy (LEBS)-are revealing new information about the changes cells undergo when cancer emerges somewhere in the body.
Within affected cells, including otherwise healthy cells far from an actual tumor, the molecules in the nucleus and cellular skeleton appear to change. On the scale of roughly 200 nanometers or less, even to the scale of molecules, an affected cell's structure becomes so distorted that light scatters through the cell in a telling way.
The ability of cancer to cause changes in distant, healthy tissue is called the "field effect" or "field of injury" effect, and is the physical mechanism that allows cells in the cheek to reveal changes triggered by a tumor far off in a patient's lung.
"Microscopic histology and cytology have been a staple of clinical diagnostics detecting micro-scale alterations in cell structure," added Backman. "However, the resolution of conventional microscopy is limited. PWS-based nanocytology, on the other hand, detects cellular alterations at the nanoscale in otherwise microscopically normal-appearing cells."
"What is intriguing is that the very same nanoscale alterations seem to develop early in very different types of cancer including lung, colon and pancreatic cancers," Backman continued. "Not only does this suggest that nanocytology has the potential to become a general platform for cancer screening, but also that these nanoscale alterations are a ubiquitous event in early carcinogenesis with critical consequences for cell function. Elucidating the mechanisms of these alterations will help us understand the initial stages of carcinogenesis and improve screening."

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X-rays linked to increased childhood leukemia risk

 

October 4, 2010

Berkeley – Diagnostic X-rays may increase the risk of developing childhood leukemia, according to a new study by researchers at the University of California, Berkeley's School of Public Health. Specifically, the researchers found that children with acute lymphoid leukemia (ALL) had almost twice the chance of having been exposed to three or more X-rays compared with children who did not have leukemia. For B-cell ALL, even one X-ray was enough to moderately increase the risk. The results differed slightly by the region of the body imaged, with a modest increase associated with chest X-rays.

The new findings, published in the October 2010 issue of the International Journal of Epidemiology, come from the Northern California Childhood Leukemia Study, a population-based case-control study that includes 35 counties in the northern and central regions of the state.
While the relationship between high doses of radiation and cancer is well known, significant debate still surrounds the health impacts from the low doses of radiation typical of conventional X-rays, or radiographs.

The dose of ionizing radiation from a single chest X-ray is roughly equivalent to the amount one would get from natural background radiation in 10 days, which is still considered low.

"The general clinical impression has been that the level of radiation a child would be exposed to today from a conventional X-ray would not confer an additional risk for cancer," said Patricia Buffler, UC Berkeley professor of epidemiology and principal investigator of the Northern California Childhood Leukemia Study. "The results of our study were not what we expected."

Leukemia is a cancer of the white blood cells, the soldiers in the body's immune system responsible for detecting and destroying disease-causing agents. According to the American Cancer Society, it is the most common childhood cancer, accounting for nearly a third of all cancers among children younger than 15 years old.
Nearly all cases of childhood leukemia are acute, with 80 percent being acute lymphoid leukemia (ALL), characterized by the overproduction of abnormal B- or T-cell lymphocytes, and 20 percent being acute myeloid leukemia (AML), in which granulocytes are overproduced.

The study included 827 children up to age 15 diagnosed with either ALL or AML. The children with leukemia were each compared with other children randomly selected from the California birth registry who were matched by factors such as age, gender, ethnicity and maternal race.

Interviews were conducted with mothers within four months of the diagnosis of leukemia, and the mothers were asked to report on the number of X-rays received by the child at least 12 months or more before the leukemia diagnosis. Mothers were also asked about their exposures to X-rays during pregnancy and the year prior to pregnancy.

The researchers noted that dental X-rays were not considered because they are so common and deliver such a low dose of radiation that exposure to those radiographs would not discriminate between individuals with high and low levels of radiation exposure.

The study found an increased risk from X-rays for ALL, but not for AML or T-cell leukemia, and there was no association with age at first exposure. Furthermore, there was no increased risk associated with prenatal exposure to X-rays or maternal X-rays occurring before pregnancy, although these exposures were uncommon in this study population.

The study authors emphasized that health care providers are already cautious in their use of X-rays in children, and use them only when necessary to diagnose potential problems such as respiratory illnesses, broken bones and fractures.

"X-rays are a valuable tool, and our findings indicate that their use should continue to be judicious," said Karen Bartley, doctoral student in epidemiology and first author of the study. "Of greater concern, perhaps, is the use of newer imaging technologies, which are becoming more common and which produce far higher doses of radiation."

Computed tomography (CT) scans, for instance, produce a 3-D image by compiling together multiple "slices" of 2-D images that were taken as the scanner moved along. A 2009 study from the National Cancer Institute projected that the 72 million CT scans received by Americans in 2007 would lead to 29,000 excess cancers. The number of scans in the United States has increased over recent decades, going from 3 million scans in 1980 to more than 70 million a year today.

"The findings about increased leukemia risk certainly warrant further investigation," said UC San Francisco radiologist Dr. Rebecca Smith-Bindman, who was not part of the X-ray study. "If even plain film X-rays are associated with an increased risk of leukemia, then one has to wonder about CT scans, some of which can generate 500 times the dose of radiation of an X-ray."

Dr. Smith-Bindman is in the process of characterizing the ionizing radiation exposure to children from CT scans as part of a study funded by the National Cancer Institute. She noted that two-thirds of the imaging procedures children undergo are conventional X-rays, accounting for about 20 percent of their exposure to radiation from medical imaging. In contrast, CT scans make up only 10 percent of the medical imaging tests children undergo, but they account for two-thirds of their ionizing radiation dose.

"The bottom line is we have to be very cautious about the use of any medical imaging techniques," said Dr. Smith-Bindman. "They can be enormously helpful for making accurate diagnoses, but tests that deliver ionizing radiation are associated with small – but real – risks of future complications related to the radiation exposure, and thus they should be used judiciously."

This study suffers from deficiencies such as recall bias. It is a repeat of the Oxford Survey of Childhood Cancers!.

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Other co-authors of the paper are Dr. Catherine Metayer and Steve Selvin from the UC Berkeley School of Public Health, and Dr. Jonathan Ducore from the UC Davis Department of Pediatrics.
This research is supported by the National Institute of Environmental Health Sciences.

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Progress towards lead free electronics

 

A step toward lead-free electronics

Lead is present every where an many products including inkjet printers and digital cameras, ultrasouns scanners and diesel fuel injectors. It was thought to be irreplaceable. Not any more.Material engineers from the University of Leeds may lead the way to 100% lead free electronics for instance.

The work, carried out at the UK's synchrotron facility, Diamond Light Source, reveals the potential of a new manmade material to replace lead-based ceramics in countless electronic devices.

European regulations now bar the use of most lead-containing materials in electronic and electrical devices. Ceramic crystals known as 'piezoelectrics' are currently exempt from these regulations but this may change in the future, owing to growing concerns over the disposal of lead-based materials.

Piezoelectric materials generate an electrical field when pressure is applied, and vice-versa. In gas igniters on ovens and fires, for example, piezoelectric crystals produce a high voltage when they are hit with a spring-loaded hammer, generating a spark across a small gap that lights the fuel.

The most common piezoelectric material is a ceramic crystal called lead zirconium titanate, or PZT.
Using a high intensity X-ray beam at the Diamond Light Source, the University of Leeds researchers have now shown that a simple, lead-free ceramic could potentially do the same job as PZT.

"With the 'Extreme Conditions' beamline at Diamond we were able to probe the interior of the lead-free ceramic- potassium sodium bismuth titanate (KNBT) to learn more about its piezoelectric properties. We could see the changes in crystal structure actually happening while we applied the electric field," said Tim Comyn, lead investigator on the project."

"PZT is the best material for the job at the moment, because it has the greatest piezoelectric effect, good physical durability, and can be radically tailored to suit particular applications," said Adam Royles, PhD student on the project. "The lead-free ceramic that we have been studying is lightweight and can be used at room temperature. This could make it an ideal choice for many applications."

In the medical field, PZT is used in ultrasound transducers, where it generates sound waves and sends the echoes to a computer to convert into a picture. Piezoelectric ceramics also hold great potential for efficient energy harvesting, a possible solution for a clean sustainable energy source in the future.

The Leeds team will continue to work at Diamond to study the transformation induced by an electric field at high speed (1000 times per second) and under various conditions using state of the art detectors.
The results of the work are published online in the journal Applied Physics Letters.


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Stop wasting food, achieve huge energy savings

WASHINGTON, Oct. 2, 2010

 Scientists at the University of Texas at Austin showed that US can achieve huge energy savings if it simply stop wasting food . They  have identified a way that the United States could immediately save the energy equivalent of about 350 million barrels of oil a year — without spending a penny or putting a ding in the quality of life: Just stop wasting food. 

They reported their study,  in American Chemical Society's( ACS's) semi-monthly journal Environmental Science & Technology; they found that it takes the equivalent of about 1.4 billion barrels of oil to produce, package, prepare, preserve and distribute a year's worth of food in the United States.
Michael Webber and Amanda Cuéllar note that food contains energy and requires energy to produce, process, and transport. Estimates indicate that between 8 and 16 percent of energy consumption in the United States went toward food production in 2007. Despite this large energy investment, the U.S. Department of Agriculture estimates that people in the U.S. waste about 27 percent of their food. The scientists realized that the waste might represent a largely unrecognized opportunity to conserve energy and help control global warming.
Their analysis of wasted food and the energy needed to ready it for consumption concluded that the U.S. wasted about 2030 trillion BTU of energy in 2007, or the equivalent of about 350 million barrels of oil. That represents about 2 percent of annual energy consumption in the U.S. "Consequently, the energy embedded in wasted food represents a substantial target for decreasing energy consumption in the U.S.," the article notes. "The wasted energy calculated here is a conservative estimate both because the food waste data are incomplete and outdated and the energy consumption data for food service and sales are incomplete."

Percentage of Various Foods Wasted in the U.S.
Fats and oils	33
Dairy	32
Grains	32
Eggs	31
Sugar and other caloric sweeteners	31
Vegetables	25
Fruit	23
Meat, poultry, fish	16
Dry beans, peas, lentils	16
Tree nuts and peanuts	16

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DOWNLOAD FULL TEXT ARTICLE: http://pubs.acs.org/stoken/presspac/presspac/abs/10.1021/es100310d
The American Chemical Society is a non-profit organization chartered by the U.S. Congress. With more than 161,000 members, ACS is the world's largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

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