US FDA recently published the levels of lead in different brands of lipstick. The report concluded that the current levels pose no safety risk.
“In fact, the FDA sets no official standard for lead in lipstick although it is reportedly considering one of 10 parts per million, the same number under discussion in Canada”.
You can access a complete results of the analysis at
http://www.fda.gov/Cosmetics/ProductandIngredientSafety/ProductInformation/ucm137224.htm#expanalyses
PTIFeature Januray 28, 2012 PF-15/2012
Studies in Medical Imaging
By Dr K S Parthasarathy
Researchers can use imaging techniques to assess the microscopic changes in the brain’s white matter, which is composed of millions of nerve fibres called axons that act like communication cables connecting various regions of the brain.
“I have a special feeling for that goal because I scored it with my head,” Pele, the legendary soccer player from Brazil said. It was Brazil’s 100th World cup goal. “My father was a soccer player and once scored five goals in a game, all with his head. That was one record I was never able to break.”
If Pele were present at the 97th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA), he would not have been pleased with some of his soccer exploits. Michael L.Lipton, associate director of the Gruss Magnetic Resonance Research Center at the Albert Einstein College of Medicine and medical director of MRI services at Montefiore Medical Center in New York and his colleagues used diffusion tensor imaging (DTI), an advanced imaging technique and found that players who head the ball with high frequency have brain abnormalities similar to those found in traumatic brain injury (TBI) patients.
Dr Lipton revealed that heading a soccer ball does not have an impact of a magnitude that will lacerate nerve fibres in the brain; but if one does it more often it could set off a cascade of responses that can lead to degeneration of brain cells.
Researchers can use imaging techniques to assess the microscopic changes in the brain’s white matter, which is composed of millions of nerve fibres called axons that act like communication cables connecting various regions of the brain.
Diffusion tensor imaging produces a measurement, called fractional anisotropy (FA), of the movement of water molecules along axons. In healthy white matter, the direction of water movement is fairly uniform and measures high in FA. When water movement is more random, FA values decrease. According to Lipton, low FA within white matter has been associated with cognitive impairment in patients with TBI,
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Dr K S Parthasarathy is a Raja Ramanna Fellow, Department of Atomic Energy
Researchers carried out DTI on 32 amateur soccer players (average age: 30.8 years), all of whom have played the sport since childhood. They estimated how often each soccer player headed the ball on an annual basis and then ranked the players based on heading frequency. They then compared the brain images of the most frequent headers with those of the remaining players and identified areas of the brain where FA values differed significantly.
“Between the two groups, there were significant differences in FA in five brain regions in the frontal lobe and in the temporo-occipital region,” Dr. Lipton said.
Soccer players who headed most frequently had significantly lower FA in these brain regions. The five regions identified by the researchers are responsible for attention, memory, executive functioning and higher-order visual functions.
Dr. Lipton said that they could identify a threshold level of approximately 1,000 to 1,500 heads per year for heading frequency that, when surpassed, resulted in detectable white matter injury. Above this level scientists observed a significant decline in their FA in the five identified brain regions.
If Professor Roentgen were a delegate at the meeting, he would have been shocked to see how medical imaging is used to rake in profit unethically. In a paper presented at the meeting, Dr Ramsey Kilani and his colleagues from Duke University at Medical Centre in Durham, North Carolina, showed that physicians who have a financial interest in imaging equipment are more likely to refer their patients for potentially unnecessary imaging examinations
The paper revealed that “self referral” in which a non radiologist physician orders imaging examination and directs patients to imaging services in which that physician has a financial interest, is a concerning trend in medicine; it is a significant driver of health care costs. In India, there are allegations of nexus between owners of medical imaging equipment and referring physicians.
In another study, a functional magnetic resonance imaging analysis of long term effects of violent video game play on the brain has found changes in brain regions associated with cognitive function and emotional control in young adult men after one week of game play. Thus far there has been little scientific evidence demonstrating that the games have a prolonged negative neurological effect. According to Dr Yang Wang, assistant research professor, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, they found that a sample of randomly assigned young adults showed less activation in certain frontal brain regions following a week of playing violent video game at home.
Dr Cyrus Raji, from the University of Pittsburg Medical Centre showed that people who ate baked or broiled fish at least once every week, had better preservation of gray matter volume on Magnetic Resonance Imaging in brain areas at risk for Alzheimer’s disease, an incurable progressive brain disease that slowly destroys memory and cognitive skills
Researchers chose 260 cognitively normal persons from the Cardiovascular Health Study. They gathered information on fish consumption using National Cancer Institute Food Frequency Questionnaire. In the study group 163 persons ate fish on a weekly basis; majority ate fish one to four times per week. Each patient underwent 3D volumetric MRI of the brain.
Researchers used a brain mapping technique that measures gray matter volume to model the relationship between weekly fish consumption and brain structure 10 years later. They analyzed the data to find out whether gray matter volume preservation associated with fish consumption reduced risk for Alzheimer’s disease. The study is complicated as it has to be controlled for age, gender, education, race, obesity, physical activity and the presence or absence of a gene that increases the risk of developing Alzheimer’s disease. Consumption of fish on a weekly basis was found to be positively associated with gray matter volumes in many areas of the brain.
The annual meeting (November 27 to December 2 this year) of the RSNA at Chicago attracts attention worldwide. Attendees contributed $ 133 million to Chicago’s economy. Virtually all the papers presented looked like hurried jobs done for the sake of the conference. The most important activity is six days of educational programmes (233 refresher courses and 127 multisessions) for radiologists, radiation oncologists, and physicists in medicine, radiologic technologists and allied professionals
Published on: February 4, 2012 – 00:10
BY K S PARTHASARATHY
Based on epidemiological studies of over fifty groups of about two million radiation exposed persons over the past several decades, specialists concluded that radiation may induce cancer at high doses.
At low doses typical in medical x-ray or nuclear medicine procedures we cannot prove the cancer inducing potential of radiation. This is because it is difficult to identify radiation induced cancers against the large number of normal cancers.
There are specialists who believe that radiation exposure at low levels is beneficial. A growing number of specialists think that low dose radiation exposure is not as harmful as was thought of so far.
No one knows whether there is a threshold dose above which only harmful effects manifest? Radiation protection depends on assumptions. We have to carry out experiments at low doses to resolve the issues scientifically.
Recently, Italian researchers claimed that low dose radiation exposure can induce biological and cellular changes that might offset the hazards of radiation. Probably, at low doses there may be protective mechanisms at work.
They studied interventional cardiologists – a group most exposed to ionising radiation among health professionals. They have a per capita exposure 2 to 3 times higher than that of radiologists.
Dr Gian Luigi Russo, Institute of Food Sciences, National Research Council, Rome and his coworkers chose ten healthy interventional cardiologists with an average age of 38 years, with a median radiation exposure of 4.7 mSv per year and lifetime exposure ranging between 20 to 100 mSv, working in the cardiac catheterization unit and
10 matched unexposed controls recruited from among the hospital and laboratory workers who did not have radiation exposure. (mSv is a unit of radiation dose; AERB prescribes an annual dose limit of 30mSv for
radiation workers)
The researchers measured many markers of oxidative metabolism in plasma, and in red blood cells (erythrocytes) and white blood cells (lymphocytes) in the two groups. In the exposed group, there was a threefold increase in hydrogen peroxide, a biochemical marker indicative of oxidative stress. When hydrogen peroxide is formed in the body, the body releases antioxidants to counteract the effect.
The researchers did not observe any significant change in the level of antioxidants in the two groups, may be because the bodies of the exposed groups generated adaptive response by activating antioxidant defence mechanisms to counteract the increase in hydrogen peroxide levels.
In interventional cardiologists, chronic exposure to low dose radiation may induce two
specific types of cellular defences against oxidative stress, the researchers argued in the August 23, 2011 issue of the European Heart Journal.
Firstly, the oxidative stress was found to be counter balanced by a 1.7 fold increase in glutathione, a measure of antioxidant response in the exposed group.
Secondly, the cardiologists exposed to radiation had significantly higher levels of Caspase-3 activity in their white blood cells. Capase-3 is a biochemical which is implicated in programmed cell deaths.
Capase-3 helps to eliminate damaged cells. This is beneficial as damaged cells may become cancerous, if they survive.
Both mechanisms may compensate for the unbalanced reactive oxygen species and contribute to maintain relatively stable equilibrium in the cell.
Other experiments carried out at the Waste Isolation Pilot Plant (WIPP), an underground lab in New Mexico and at the Lovelace Respiratory Research Institute, Albuquerque gave interesting results (Health Physics, March 2011).
WIPP is located at a depth of 650 metre in the middle of a 610 metre thick ancient salt deposit that has been stable for more than 200 million years.
The radioactivity content of the salt deposit is extremely low. The radiation levels in the lab are ten times lower than the normal natural background radiation levels. The contribution to the background from potassium-40, the only identifiable radionuclide present in the lab can also be reduced further by using a modest amount of shielding. Massive, 650 metre thick, salt reduced the cosmic ray background.
Researchers incubated Deinococcus Radiodurans, a bacterium which is highly resistant to radiation, above-ground and in WIPP in a 15 cm thick pre-World War II steel chamber; that steel is not contaminated by traces of radio-nuclides from nuclear weapons fallout.
The radiation level underground was 20 per cent of the surface radiation levels and in the pre WW II chamber it was 30 per cent of those underground. Overall reduction was about 15 times.
Scientists monitored the bacterial growth by assaying for protein, optical density of the cultures and cell agar plate counts. Though data had relatively high variability, the three indicators of cell growth demonstrated that the cells grown underground were inhibited and grew increasingly so with increasing time underground (Health Physics, 2011).
In the second experiment, researchers exposed a type of human lung cells at 1.75 mGy per year; another sample of cells to 0.3 mGy per year by using a 10 cm lead shield. The former corresponds to a typical background radiation level. (Gy is a unit of radiation dose It is equal to an energy absorption of one joule per kg.). They controlled the temperature, carbon dioxide and humidity levels in the two incubators in which the cells were placed ensuring that these parameters were statistically the same. They analyzed the exposed cells directly by standard methods for the presence of heat shock proteins or by exposing the cells to a single x-ray dose of 0.10Gy and then assayed for heat shock proteins.
Shielding cells from natural radiation up-regulated (initiated the process of increasing the response to a stimulus) the expression of two out of three stress proteins and follow on x-ray exposure further up-regulated expression.
Results were similar with the bronchial epithelial cells. Both studies demonstrated a stress response when cells were grown under reduced radiation conditions. Does it show that radiation is necessary for normal growth?
It may lead to increasing the levels of radiation considered safe; it will have a profound impact on the economics of decommissioning nuclear facilities, long term storage of radioactive waste, construction of nuclear power facilities among others.
This was part of a $150 million, five-year long, low-dose research project recommended by 26 scientists highly regarded in radiobiology research community and representing competing radiation effects hypotheses. Let us hope that they will develop a model based on sound science.
Presently, one out of every 144 persons in USA are living with total knee replacement .The rise is sharpest among the youg. Osteoarthritsis is known to be the reasons. Other details are available at the following URL
http://www.eurekalert.org/pub_releases/2012-02/aaoo-4ma020712.php
A news report suggests that orthopaedic defensive medicine in US costs $ 2 billion.
You may access the report at:
http://www.auntminnie.com/index.aspx?sec=sup&sub=imc&pag=dis&ItemID=98254&wf=4774
The study thus revealed that the percentages of particular tests that were ordered defensively:
THE BIHAR TIMES
A Passage to Bihar
February 7, 2012
Dr P K Iyengar: a doyen among sientists
Dr K S Parthasarathy
Dr P K Iyengar, one of the pioneers who along with his team toiled tirelessly to place India in the once forbidden, exclusive nuclear club is no more. He was 80.
He joined the Department of Atomic Energy (DAE) in 1952.He served DAE in many capacities before retiring as Chairman, Atomic Energy Commission. He inspired a generation of young scientists and engineers in the field of nuclear science and technology.
He and Dr Raja Ramanna believed that if we want to get the most talented people in a developing country like India, we have to choose every year a few hundred from the vast pool of academically sound young people. If ten out of two hundred turn out to be outstanding, he rated this “statistical operation” as successful.
Iyengar was immensely proud of the multidisciplinary ambience provided at Trombay, which turned the outstanding young people, he chose, into leaders as they enhanced their analytic skills and creativity.
In 1956, he went to Chalk River, Canada; his association with Bertram Neville Brockhouse, later a Nobel Laureate, became a turning point in his career.
They measured the dispersion relations based on Born’s theory of lattice dynamics in germanium. Within three years, they published five papers on the neutron spectrum of germanium and manganese compounds.
When Brockhouse passed away, Dr Iyengar acknowledged him as his mentor and friend (Current Science, 10 December 2003). Brockhouse discovered a new branch of research, the neutron analogue of Raman Effect. Brockhouse-Iyengar collaboration turned out to be one of the most productive for India.
After Iyengar’s return to India, K R Rao, B A Dasannacharya and A P Roy worked with Brockhouse at Chalkriver and later after 1962, at McMaster University. In his Nobel Lecture titled “Slow neutron spectroscopy and the grand atlas of the physical world”, Dr, Brockhouse referred to his papers with Dr Iyengar and those with other collaborators. Iyengar set up a world class neutron scattering group in Trombay.
Iyengar’s enthusiasm for physics was infectious. He argued, cajoled and coaxed and woke up every one from deep slumber. Every minute spent with him was exciting and informative. Despite his indifferent health, he kept himself up to date.
He questioned every one constantly. “Why should they not use plutonium carbide as fuel for the fast breeder reactor?’, “They” meant scientists in the Indira Gandhi Centre for Atomic Research (IGCAR)! Is not fabricating plutonium carbide fuel very challenging? “Every one knows enough about plutonium oxide; what is so innovative about it?
In the next few minutes, he praised Brazil for making uranium enrichment technology more efficient. Tweaking the design of the rotors did the trick, he revealed. From fission to fusion, from “mega- gauss reactions” to superconductivity, he drove home his ideas effortlessly.
According to M. Srinvasan, a close associate, Iyengar was very sharp in his observations and had a keen eye for detail. He was strong in engineering design and had an elephantine memory.
Srinvasan remembers that when news papers covered “cold fusion”, Dr Iyengar who was always interested in exciting new things, convened a meeting of neutron physicists, chemists, chemical engineers, etc. Within six weeks, 12 groups started working on it.
Iyengar did not forgive me for writing an editorial titled “Fuss about fusion: more heat than light” in The AERB Newsletter (5, 1, 1989).The edit reflected the views of mainstream scientists. He admonished me for relying on popular magazines such as the New Scientist. Thereafter, whenever we met, he talked about the new developments in the field of “Low Energy Nuclear Reactions”.
Dr M R Iyer, another colleague remembers that Iyengar, a storehouse of anecdotes credited Dr A K Ganguly, a pioneering safety specialist with saving installations at Kalpakkam when 2004 tsunami stuck. In the seventies, Dr Ganguly insisted that key components near the coast must be installed on high pedestals. According to Iyengar, safety committee members even taunted Dr Ganguly as to “who is this Japanese girl: Tsunami?”
A scientometric portrait of Iyengar drawn by Kademani and co-workers in Library Science in 1994 revealed that he is eminently qualified to be a role model for the younger generation. He published prolifically in many technical journals. Many who retired from Trombay will miss their mentor; India will miss a restless leader who fearlessly argued for self reliance in very field of endeavour.
Published: January 26, 2012 01:39 IST | Updated: January 26, 2012 01:39 IST
Is the edifice of radiation protection built on a lie?
The Hindu THE WAY FORWARD: The public need to be educated regarding the importance of acceptable levels of risk. Photo: K.R. Deepak
The Linear No Threshold concept assumes that the risk from radiation exposure varies linearly with total dose with no threshold
Recently, Edward Calabrese, an environmental toxicologist at the University of Amherst found out that Dr Hermann J. Muller, famous radiation geneticist knowingly lied in his Nobel Prize lecture when he claimed that there was “no escape from the conclusion that there is no threshold.” Calabrese described his discovery in September in Archives of Toxicology and Environmental and Molecular Mutagenesis
In 1927, Muller discovered that x-ray irradiation produces mutations in male fruit-fly germ cells. For this, he received the Nobel Prize in Physiology or Medicine in 1946. Many believe that Muller’s assertion became a corner stone of radiation protection. This is the Linear No Threshold (LNT) concept which assumes that the risk from radiation exposure varies linearly with total dose with no threshold and any dose however small has an adverse effect.
Expert bodies accepted this model because of its simplicity in the management of radiation protection programmes.
“However, it has done much damage to speak of ‘no safe level of radiation’ in scaring not only the public, but also those professionally involved in peacetime health physics who have not been involved in high levels and emergency situations,” Allen Brodsky, Adjunct Professor of Radiation Science, Georgetown University responded to an e-mail query.
In response to an e-mail query Calabrese disclosed that a reviewer of his article on the history of dose-response argued that he had not done a good job on the Muller section and key early radiation mutation studies. Calabrese found that a paper from the University of Rochester by Curt Stern and Casper on fruit-fly irradiation and germ cell mutation was published in 1948 but it was actually completed in August of 1946.
“This study was very important because it did not support a linear dose response and because it was the strongest study to date…using the lowest dose rate etc. I knew that Muller gave his Nobel Prize lecture on Dec. 12, 1946. So the question was whether Muller was aware of the new findings before his major speech,” Calabrese replied
By reviewing Stern’s correspondence with Muller, Calabrese established that Muller knew of the findings which contradicted his theory a month prior to the Nobel Lecture.
Calabrese asserts that Muller’s passionate beliefs influenced the way government and society viewed the risks of low doses of radiation. The 1956 recommendations of the US National Academy of Sciences (NAS) BEAR (Biological Effects of Atomic Radiation) I Committee reflected these views. Regulating ionizing radiation as if there was no safe dose began!
James Schwartz, a biographer of Muller, Kenneth Muller, Hermann Muller’s grandson and Elof Axel Carlson, Muller’s former student do not agree with Calabrese. Some feel that Calabrese, a supporter of radiation hormesis (beneficial effect) has conflict of interest. The balance of evidence shows that the edifice of radiation protection is not built on a lie.
Dr Evan B. Douple, Associate Chief of Research at the Radiation Effects Research Foundation, Hiroshima, does not think that the LNT hypothesis would have lost its applicability if Professor Muller would not have made the passionate statement in his speech.
“……. by the time the BEIR (Biological Effects of Ionizing Radiation) committees of the National Academy of Sciences began updating the risk estimates, the mutation risk was superseded by the risk of cancer. Having been intimately involved with the BEIR VI and BEIR VII studies, I can assure you that the voluminous data reviewed by the committee members that related to supporting or refuting LNT, was not swayed or overly influenced by the shape of a dose-response curve in the mutation work of Muller,” Douple responded. (Dr Douple was Director, Board on Radiation Effects Research, National Research Council)
He is not even sure that Calabrese’s interpretation and assessment that Muller was deceptive in his presentation is necessarily accurate or fair.
“Although somatic mutations became a dogma for radiation carcinogenesis, the LNT for carcinogenesis was based on (a) analyses of cancer induction in rodent models, (b) biophysical characteristics of energy deposition, ionizations, and DNA damage in cells, and (c) the early epidemiological studies of cancer in the Japan A-bomb survivors,” he clarified in an e-mail.
He does not think that the conjecture and personal interpretation of an untestable accusation will have significant impact among the radiation protection community.
Prof Ludwig E. Feinendegen, Heinrich-Heine University, Germany thought that “the new revelations on low-dose effects in the realm of biological responses are making an impact on the radiation protection community — as it appears currently from the defensive manner of their arguments for keeping the LNT model, at least for the time being. Calabrese has done us a great favour by his new paper on Mueller’s mistake.”
That there is no safe level of radiation continues to be a useful assumption in radiation protection. It is yet to be proved as a scientific fact.
Douple believes that the exhaustive efforts of those who claim that demonstrating hormesis (beneficial effect) or the presence of thresholds will revolutionize the radiation protection field are misguided.
“We need to educate the public regarding the importance of ‘acceptable levels of risk’—levels that are believed to include risks, but risks for adverse effects that are so small that one would not be able to observe and measure an excess of the effects with a realistic study. Only then will the fear and paranoia associated with radiation effects gradually become less and less and sources for energy production can be fairly and objectively be evaluated,” Douple proposed as a realistic way forward.
Regulators want dose limits for enforcing radiation protection. What is the threshold dose value they will accept for enforcement? Calabrese and his followers have not yet responded to my query.
The French Academy of Sciences, the only scholarly body which has views closer to those of Calabrese on hormesis conceded that on the basis of present knowledge, it is not possible to define the threshold level (between 5 and 50 mSv) or to provide the evidence for it. The dose limit for workers recommended by the International Commission on Radiological Protection (ICRP) is 20 mSv per year averaged over five years with no year exceeding 50 mSv. The dose levels to radiation workers achievable are so low that the risk from them is negligible. Negligible risk is no risk at all. That we cannot rule out beneficial effects of radiation is also a comforting thought.
K.S. Parthasarathy
Raja Ramanna Fellow, Department of Atomic Energy (ksparth@yahoo.co.uk)
Keywords: radiation exposure
