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Fighting blindness: A miniature telescope (show above, sitting on a finger) implanted into the eye improves vision in people with macular degeneration. The four-millimeter-long implant contains two wide-angle glass lenses, which magnify images onto the retina.
Credit: VisionCare

A new device may help restore sight for people with severe macular degeneration.

MIT Technology Review, April 3, 2009, by Emily Singer — A miniature telescope implanted into the eye could soon help people with vision loss from end-stage macular degeneration. Last week, an advisory panel for the Food and Drug Administration unanimously recommended that the agency approve the implant. Clinical trials of the device, which is about the size of a pencil eraser, suggest it can improve vision by about three and a half lines on an eye chart.

“This is one of the few options for people with end-stage macular degeneration,” says Kathryn Colby, an eye surgeon at the Massachusetts Eye and Ear Infirmary, in Boston, who helped develop the surgical procedure used to implant the device.

Macular degeneration is the leading cause of blindness in people age 65 and older, affecting more than 10 million Americans. The disease strikes the center of the retina, called the macula, which is especially important for reading, watching television, and recognizing faces. While some treatments exist to slow progression of the disease, no treatments are currently available for those in the latest stages of the disease, who have irreversible damage to the macula. An estimated 50,000 to 70,000 people per year fall into this category.

The implant, developed by VisionCare Ophthalmic Technologies, a start-up based in Saratoga, CA, consists of two lenses within a small glass tube. Once inside the eye, it works like a fixed telephoto lens, acting in conjunction with the cornea to project a magnified image of whatever the wearer is looking at over a large part of the retina. Because only the central parts of the retina are damaged in the disease, magnifying the image on the eye allows the retinal cells outside the macula to detect the object and send that information to the brain. (These cells are normally involved in peripheral vision and normally generate low-resolution visual information compared to the macula cells–you can’t read a sign in your periphery, for example. But magnifying the image also has the advantage of making it easier for the cells to interpret.)

“This change in vision is significant to patients,” says Allen Hill, PCEO of VisionCare. In addition to improving vision, it “provides the ability to have normal eye contact, which is a crucial part of social interaction,” says Eli Peli, a scientist at The Schepens Eye Research Institute, who has consulted for the company.

During the implant procedure, surgeons first remove cataracts from the eye. (Because both macular degeneration and cataracts are age related, most patients with end-stage macular degeneration also have cataracts.) They then insert the telescope, which is held in place by the resident tissue.

The device is implanted in only one eye–patients use this eye for detailed vision and the untreated eye for peripheral vision. That takes some getting used to, says Peli. “Instead of using two parts of the same eye, they must switch between two eyes; if they see someone coming but can’t tell who it is, they need to switch to other eye.”

One safety concern associated with the implant is loss of the endothelial cells that are responsible for keeping the cornea transparent. While cell loss occurs with any eye surgery, implantation of the telescope requires a larger incision than typical cataract surgery and thus destroys more endothelial cells. However, scientists have found that cell loss stabilizes over time. Patients with the implant lose about 3 percent of their endothelial cells per year, compared to about 2.5 percent to 3 percent for patients undergoing traditional cataract surgery. Because endothelial cells replicate, substantial loss of these cells can worsen vision.

The FDA is expected to approve the telescope, as the agency usually follows the advice of its advisory panels. VisionCare plans to market the device following FDA approval, estimated for late 2009. The device has already been approved for use in Europe, though the company plans to launch the product first in the United States.

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HSCI co-director David Scadden and colleagueshave identified in mice a cellular mechanism that directs stem cells to their destination.
File Justin Ide/Harvard News Office

How stem cells find their way around

The Harvard Gazette, April 3, 2009, by B.D.Colen — Harvard Stem Cell Institute (HSCI) researchers have for the first time identified in mice a cellular mechanism that directs stem cells to their ultimate destination in the body.

The finding in blood stem cells by HSCI co-director David Scadden and colleagues holds the promise of greatly increasing the efficiency of the bone marrow transplants used to treat various forms of cancer and has enormous implications for future therapies utilizing all forms of stem cells.

“Figuring out the mechanisms that tell stem cells how to get to where they need to go is a major problem when we’re thinking about stem cell therapies,” said Scadden, who is the director of the Center for Regenerative Medicine at Massachusetts General Hospital and is also the co-chairman of Harvard’s new Department of Stem Cell and Regenerative Biology.

Hal Broxmeyer, chairman and Mary Margaret Walther Professor of Microbiology/Immunology and scientific director of the Walther Oncology Center at Indiana University School of Medicine, said the new study “provides crucial, important, and physiologically relevant information on [blood stem cells’] homing/engrafting capability … Most importantly, the results from this study open up the possibility of using a relatively simple means to enhance homing/engraftment and mobilization of” blood stem cells in bone marrow transplantation. “… I look forward with great anticipation to seeing this work by Scadden’s group successfully translated into the clinic for patients,” Broxmeyer said.

Scadden, a physician-scientist who specializes in the treatment of cancers of the blood system, notes that the “system has paved the way for so much of our understandings of stem cell therapy.” Bone marrow transplantation, which has been used for several decades to treat a number of cancers, is essentially stem cell therapy, as the donated marrow transplanted into the patient carries blood stem cells that it is hoped will provide the patient with a new blood-producing system.

In this new study, published today in the journal Nature, Scadden’s team reports identifying the cellular pathway — the route by which signals travel from receptors on the cell’s surface to direct the action of the cell — that serves as a kind of GPS directing the travel of the cell. Additionally, the researchers report a number of already approved drugs — used to treat a variety of diseases — that activate this directional system.

“This is a pathway that’s been intensively studied because of its relationship to hormone function and blood pressure,” Scadden explained. “There is a wide range of drugs that have been developed that effect this pathway, for everything from blood pressure regulation to asthma control.

“This is a critical pathway in a number of cells,” Scadden continued. “It’s important in the heart and the blood vessels, in the brain, and in platelets. We found out not only that it’s there, but that it’s absolutely critical for stem cells to find their way home. And if you stimulate it,” he said, “you can improve the cell’s path-finding ability.”

Serendipitously, another group of HSCI researchers, led by Leonard Zon at Children’s Hospital Boston, has approval from the U.S. Food and Drug Administration to begin a clinical trial seeking to improve the efficacy of bone marrow transplantation, using a compound that activates the pathway identified by the Scadden group — prostaglandin E2.

“Ours was a mechanistic study,” said Scadden, one in which he and his colleagues sought to find the mechanism that directs stem cells to where they belong and can best multiply. Meanwhile, he said, Zon and colleagues approached the problem from another direction. “Len was saying, ‘I’m going to test every drug that’s known on blood stem cells in zebra fish [the system in which Zon does his research]’ and he found one that activates this pathway,” publishing that work in Nature just about two years ago.

………………………………………

Researchers successfully track voyage of single stem cell

The Harvard Gazette — The title of the letter in the Dec. 3 edition of the journal Nature — “Live-animal tracking of individual haematopoietic stem/progenitor cells in their niche” — doesn’t begin to describe it, this real-life, real-time view of a single stem cell making its way to its ultimate home inside the bone-marrow cavity of a living mouse.

As David Scadden, co-director of the Harvard Stem Cell Institute and director of the Center for Regenerative Medicine at Massachusetts General Hospital (MGH) explains, it was first hypothesized 30 years ago that “stem cells have to have a particular location and a particular tissue type in order to survive, and without that they won’t be able to produce cells such as blood cells.”

In 2000, researchers working in drosophila — fruit flies — verified the hypothesis. In their letter to Nature, Scadden, postdoctoral fellow Cristina Lo Ceslo, Charles P. Lin of MGH’s Wellman Center for Photomedicine, and colleagues, describe tracking single stem cells transplanted into living mice.

Scadden, a hematologist-oncologist who provides cancer patients with bone-marrow transplants — which are essentially blood stem cell transplants — says, “we inject cells into a vein, and some of them find their way to where they need to end up, but we need to know what happens to them. And more important, we need to discover what we can do to increase the efficiency of the process, to make sure that the stem cells ‘take’ and thrive.”

Now, Scadden says, “we can actually watch the cells divide; we can see the process by which cells engraft, and regenerate the bone marrow.”

The most exciting thing coming from this work, Scadden says, is that we know there are drugs that improve stem cells getting to where they need to go and drugs that appear to stimulate the successful establishment of the transplanted stem cells. The next step, he says, is working with those drugs in clinical trials in marrow-transplant patients.

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If DNA computing can be used to break codes, then the machinery of life can be exploited to encrypt data too

MIT Technology Review, March/April 2009 — Molecular biologists have long thought of DNA as an information storage device. The body processes this information with an impressive array of computing machinery which, since the 1990s, we’ve exploited to carry out a few of our own calculations.

DNA computing may not be fast but it is massively parallel. With the right kind of setup, it has the potential to solve huge mathematical problems. It’s hardly surprising then, that DNA computing represents a serious threat to various powerful encryption schemes such as the Data Encryption Standard (DES).

But if DNA can be used to break codes then it can also be exploited to encrypt data. Various groups have suggested using the sequence of nucleotides in DNA (A for 00, C for 01, G for 10, T for 11) for just this purpose. One idea is to not even bother encrypting the information but simply burying it in the DNA so it is well hidden, a technique called DNA steganography.

But that all sounds to simple for Nang King, an independent researcher who today puts forward an entirely new approach based on the way in which information from DNA is processed inside cells. The processing works in two stages called transcription and translation.

In transcription, a DNA segment that constitutes a gene is converted into messenger RNA (mRNA) which floats out of the nucleus and into the body of the cell. this happens only after the noncoding parts of the gene have been removed and the remaining sequences spliced back together.

In translation, molecular computers called ribosomes read the information that mRNA carries and uses it to assemble amino acids into protein chains.

This is a one way process. Information can be transferred from DNA to a protein but it cannot be converted back. There reasons are various. How would this process know where to reinsert the noncoding regions of DNA that were originally cut out or what these noncoding sequences would have consisted of in the first place?

Nang’s idea is that Alice encodes her message in the original DNA sequence and allows this to be transcribed and translated. The resulting protein is then like a public key which can be sent to Bob through a public channel. Meanwhile, Alice sends Bob the secret key which consists of the information he needs to reassemble the DNA such as the location of the noncoding regions that need to be reinserted.

Nang says that this form of cryptography is surprisingly secure to a number of powerful attacks. But he also points out various weaknesses such as that the encryption becomes increasingly difficult if more complex keys are used.

But it piques the interest for sure. And as an additional weapon in the cryptographer’s armoury, it’s surely an idea worthy of further study.

Ref: arxiv.org/abs/0903.2693: A Pseudo DNA Cryptography Method

Computer Science > Cryptography and Security

Title: A Pseudo DNA Cryptography Method

Authors: Kang Ning

(Submitted on 16 Mar 2009)

Abstract: The DNA cryptography is a new and very promising direction in cryptography research. DNA can be used in cryptography for storing and transmitting the information, as well as for computation. Although in its primitive stage, DNA cryptography is shown to be very effective. Currently, several DNA computing algorithms are proposed for quite some cryptography, cryptanalysis and steganography problems, and they are very powerful in these areas. However, the use of the DNA as a means of cryptography has high tech lab requirements and computational limitations, as well as the labor intensive extrapolation means so far. These make the efficient use of DNA cryptography difficult in the security world now. Therefore, more theoretical analysis should be performed before its real applications.
In this project, We do not intended to utilize real DNA to perform the cryptography process; rather, We will introduce a new cryptography method based on central dogma of molecular biology. Since this method simulates some critical processes in central dogma, it is a pseudo DNA cryptography method. The theoretical analysis and experiments show this method to be efficient in computation, storage and transmission; and it is very powerful against certain attacks. Thus, this method can be of many uses in cryptography, such as an enhancement insecurity and speed to the other cryptography methods. There are also extensions and variations to this method, which have enhanced security, effectiveness and applicability.

1. arXiv:0903.2693 [pdf, other]

Title: A Pseudo DNA Cryptography Method

Authors: Kang Ning

Comments: A small work that quite some people asked about

Subjects: Cryptography and Security (cs.CR)

2. arXiv:0903.2310 [pdf]

Title: Analysis of the Relationships among Longest Common Subsequences, Shortest Common Supersequences and Patterns and its application on Pattern Discovery in Biological Sequences

Authors: Kang Ning, Hoong Kee Ng, Hon Wai Leong

Comments: Extended version of paper presented in IEEE BIBE 2006 submitted to journal for review

Subjects: Data Structures and Algorithms (cs.DS); Discrete Mathematics (cs.DM); Information Retrieval (cs.IR); Quantitative Methods (q-bio.QM)

3. arXiv:0903.2015 [pdf]

Title: A Deposition and Post Processing Approach for the Longest Common Subsequence Problem

Authors: Kang Ning

Comments: 25 pages, 6 figures

Subjects: Data Structures and Algorithms (cs.DS); Discrete Mathematics (cs.DM); Combinatorics (math.CO)
Why Our Time Dimension is About to Become Space-Like

MIT Technology Review/ the physics arXiv blog, by KFC — It don’t get much weirder than this. The universe is about to lose its dimension of time says a group of theoretical astrobods at the University of Salamanca in Spain. And they got the evidence to prove it.

The idea comes from the study of braneworlds: the thinking that the universe we see around us is a 4-dimensional cosmos called a braneworld embedded in a multidimensional universe. The “signature” of our universe is the number of space and time-like dimensions it has: in our case we got 3 space-like dimensions and one time-like dimension. It’s what astrobods call a Lorentzian universe. So far so good: lots of astronutters think the same thing.

But our universe may not always have been like this. Some theorists think it may once have had a Euclidean signature meaning that all the dimensions were space-like. Now Marc “Bars” Mars and a few pals in Spain say that the Universe’s signature might be about to flip from Lorentzian to Euclidean. In other words, our dimension of time is about turn space-like. Gulp!

This ain’t entirely bonkers and here’s why. Bars Mars has calculated what it’s like to be an observer in a universe that is about to flip and get this: it would look as if it were expanding and accelerating away from us. Sound familiar?

Yep, it’s exactly what astrobods have been observin over the last few years, a phenomenon they attribute to dark energy. If Bars Mars is right, dark energy ain’t got nothing to do with it and we’re all starin’ down the barrel of a cosmic catastrophe.

Still, maybe four space-like dimensions will be better than three. Who needs time anyway?

Ref: arxiv.org/abs/0710.0820: Is the Accelerated Expansion Evidence of a Forthcoming change of Signature?

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CDC Scientists Find Perchlorate in Samples of Powdered Infant Formula

By Miranda Hitti
WebMD Health News

Reviewed by Louise Chang, MD

April 6, 2009 — CDC scientists have found a chemical called perchlorate in samples of powdered infant formula.

Perchlorate occurs naturally in the environment; it’s also made for use in rocket propellant, explosives, fireworks, and road flares.

Perchlorate has been found in drinking water in some areas of the country, as well as in food and breast milk.

High levels of exposure to perchlorate may disrupt the function of the thyroid gland, which is needed for normal growth and development of the central nervous system, according to background information from the FDA.

The formula findings, published online in the Journal of Exposure Sciences and Environmental Epidemiology, raise more questions than answers.

Those questions include the health effects of perchlorate from powdered infant formula, whether iodine supplementation might offset perchlorate-related thyroid problems, and whether the formula samples that were tested were representative of powdered infant formula nationwide.

“It’s important to note that infant formula contains iodine and that iodine would be expected to ameliorate any potential effects that perchlorate would have,” Ben Blount, PhD, Chief of the CDC’s Perchlorate Biomonitoring Laboratory, tells WebMD.

Perchlorate Study

The researchers — who included Blount and Joshua Schier, MD, a medical toxicologist with the CDC’s National Center for Environmental Health — bought four types of powdered infant formula at several grocery stores in one U.S. city in 2006.

Here’s what they bought (no brands or companies are mentioned in the study):

· Powdered infant formula made from cow’s milk (with lactose)

· Powdered infant formula made from lactose-free cow’s milk

· Powdered infant formula made from soy

· Powdered infant formula made from synthetic amino acids

After mixing the formula with perchlorate-free water, the researchers checked perchlorate levels in the formula. Then they estimated how much perchlorate babies of various ages and sizes might be exposed to, based on their feeding schedule, how much perchlorate was in local tap water, and other factors.

The results: “Perchlorate was found in all brands and types of infant formula,” with the highest levels in powdered infant formulas made from cows’ milk containing lactose. That’s probably because mammals can store perchlorate in breast tissue during lactation, Blount notes.

And in certain hypothetical situations — based on water levels of perchlorate and formula doses — babies might be exposed to more perchlorate than health officials believe to be safe.

But more work is needed to see if those estimates reflect reality.

“There needs to be a closer and much more detailed analysis of how much perchlorate is actually getting into infants’ bodies,” Schier tells WebMD. The U.S. Environmental Protection Agency (EPA) doesn’t regulate perchlorate in drinking water, but that may change.

In January 2009, the EPA issued an interim health advisory setting an upper limit on perchlorate levels in public drinking water. The EPA is also seeking advice from the National Academy of Sciences before deciding whether to set a national regulation for perchlorate in drinking water.

Meanwhile, if you want to find out if your drinking water contains perchlorate, the EPA suggests calling your drinking water utility or state drinking water program to learn the results of past perchlorate monitoring or to find out if your state requires monitoring.

If your state doesn’t require perchlorate monitoring, you can send a sample of your tap water to a lab that’s certified to analyze perchlorate or similar compounds. The EPA’s web site has a state-by-state list of links to drinking water labs.

Bottled Water, Treated Water an Option

Schier’s study focuses on perchlorate in powdered infant formula, not in water. But if there’s perchlorate in your drinking water, perchlorate would get into formula made with that water.

Background information posted on the FDA’s web site states that “If you live in one of the few areas where perchlorate in the public drinking water is above 15 parts per billion, FDA recommends using water that is lower in perchlorate levels, such as bottled water or water from a home treatment device certified for perchlorate removal, to reconstitute your infant’s formula.”

Perchlorate can be removed from drinking water by reverse osmosis technology. But if you’re considering installing a home treatment unit, the EPA recommends contacting the manufacturer to ask whether the unit can remove perchlorate from your water supply.

The FDA has also investigated perchlorate in foods. Those findings, which were published last year, are consistent with the new CDC report, are well below the EPA’s level of concern, and reflect the “ubiquitous” environmental nature of perchlorate, an FDA spokesman tells WebMD.

……………………………………………………

Powdered Cow’s Milk Formula Contains Thyroid Toxin

Researchers from the U.S. Centers for Disease Control and Prevention (CDC) have reported that 15 brands of powdered infant formula are contaminated with perchlorate, a rocket fuel component detected in drinking water in 28 states and territories.

The two most contaminated brands, made from cow’s milk, accounted for 87 percent of the U.S. powdered formula market in 2000, the scientists said.

The CDC scientists did not identify the formula brands they tested.

The little-noticed CDC findings, published in the March 2009 edition of the Journal of Exposure Science and Environmental Epidemiology, raise new concerns about perchlorate pollution, a legacy of Cold War rocket and missile tests. Studies have established that the chemical is a potent thyroid toxin that may interfere with fetal and infant brain development (Kirk 2006).

The CDC team warned that mixing perchlorate-tainted formula powder with tap water containing “even minimal amounts” of the chemical could boost the resulting mixture’s toxin content above the level the Environmental Protection Agency (EPA) considers safe. Many scientists contend that the EPA “safe” level is too high to protect public health.
“Safe” level too high

The risk to infants being fed cow’s milk-based formula may be even greater than the CDC assessment suggests. A CDC study in 2006 found that trace perchlorate exposure considerably below the EPA’s “safe” level (0.7 micrograms of perchlorate per kilogram of body weight per day, called the reference dose, or RfD) altered women’s thyroid hormone levels (Blount et al 2006a).

Based on this study, the Environmental Working Group has recommended that EPA promptly set a legally enforceable upper limit on perchlorate contamination in drinking water, consistent with the latest science on perchlorate’s toxic effects.
Obama EPA considering action

At her January 14 confirmation hearing, EPA administrator Lisa Jackson promised California Senator Barbara Boxer, whose state has borne the brunt of perchlorate contamination from old launch sites and aerospace facilities, that she would act “immediately” to reduce perchlorate contamination in drinking water in order to protect children and pregnant women.

Since her confirmation, however, Jackson and EPA have not made public a plan of action.
Pentagon lobbied Bush administration

Last fall, the Bush administration’s EPA leadership touched off a major furor by declaring that perchlorate posed no threat to most Americans and did not need to be regulated as a drinking water pollutant.

The decision was widely regarded as a major victory for the Pentagon and defense and aerospace contractors reluctant to pay clean-up costs that could mount into the hundreds of millions of dollars.

EPA’s move triggered protests from consumers, lawmakers, scientists and medical experts – among them, two of the agency’s prestigious outside science advisory panels.

Melanie A. Marty, a senior career EPA official and chair of EPA’s Children’s Health Protection Advisory Committee, declared that the agency’s refusal to regulate perchlorate in drinking water exposed some infants to “the life-long consequences of impaired brain development.”

On January 8, EPA issued a non-binding “health advisory” on perchlorate and asked the National Academy of Sciences to review the issue.

EWG dismissed EPA’s action as “nothing more than an effort to dodge the issue and buy time for the defense, aerospace and chemical industries.”

Years of federal inaction have prompted some states to set their own mandatory limits for perchlorate in drinking water: California, at 6 ppb and Massachusetts at 2 ppb. While recent scientific research has shown these standards too weak to protect public health adequately, they are far more stringent than EPA’s action in January.
Studies find pollution in people, food

Concern about perchlorate pollution has intensified as a series of studies have found perchlorate in the urine of every American tested by the CDC and in breast milk (Blount et al 2006b, Pearce et al 2007).

In 2008, an EWG analysis found that toddlers were especially vulnerable to perchlorate exposure from contaminated food. Toddlers, who are growing rapidly, consume large amounts of food daily, relative to their size. Moreover, those who live in places like California and Texas, where high perchlorate levels have been measured in some drinking water supplies, are doubly exposed to perchlorate contamination.

EWG’s analysis was based on 2008 federal Food and Drug Administration (FDA) tests that found almost 75 percent of food and beverage samples tainted with perchlorate, possibly from contaminated irrigation water (Murray et al 2008).
CDC finds perchlorate in 15 formula brands

The new CDC study is the first to examine perchlorate exposure of infants fed powdered formula reconstituted with contaminated drinking water. The CDC team tested 15 brands of powdered infant formula in four categories: cow milk-based with lactose, cow milk-based lactose-free, soy-based and elemental.

“Perchlorate was found in all brands and types of infant formula tested,” the scientists said. The worst perchlorate contamination was found in formula based on cow’s milk with lactose.

The CDC team said that combining cow’s milk/lactose formula with water containing perchlorate at just 4 parts per billion (ppb) could cause 54 percent of infants consuming the mix to exceed EPA’s “safe” level.

The number of babies exposed to unsafe levels of perchlorate would rise if, as EWG and many other science and health advocates argue, the EPA “safe” level were lowered to reflect recent scientific studies.
Formula required to contain iodine

While these findings are of concern, the CDC scientists also note that FDA requires infant formula to be supplemented with iodine, a nutrient that can counteract the negative effects of perchlorate on the thyroid gland. The range of required iodine concentrations in formula is between 5 and 75 micrograms per 100kcal of energy.

Iodine supplements at higher levels may offer some protection from the toxic effects of perchlorate. But the CDC scientists estimate that those brands that contain only the minimum iodine concentration of 5 micrograms would leave infants iodine-deficient and thus more vulnerable to the toxic effects of perchlorate. A scenario in which formula contained 40 micrograms of iodine (per 100kcal of energy) would offer more protection for infants, but the scientists stress that even adequate iodine intake among formula-fed infants is not guaranteed to prevent “perchlorate-induced thyroid dysfunction.”
Strict drinking water regulation of perchlorate needed

This study represents perhaps the strongest evidence to date supporting the need for a legally enforceable safe drinking water level that protects pregnant women, infants and others who are most vulnerable to the effects of this harmful chemical.

The new Obama administration leadership at EPA can and should take steps to reduce infants’ exposures to perchlorate pollution in tap water.

Journal of Exposure Science and Environmental Epidemiology advance online publication 18 March 2009; doi: 10.1038/jes.2009.18

Perchlorate exposure from infant formula and comparisons with the perchlorate reference dose

Joshua G Schiera, Amy F Wolkina, Lisa Valentin-Blasinib, Martin G Belsona, Stephanie M Kieszaka, Carol S Rubina and Benjamin C Blountb

1. aDivision of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA

2. bDivision of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Abstract

Perchlorate exposure may be higher in infants compared with older persons, due to diet (infant formula) and body weight versus intake considerations. Our primary objective was to quantitatively assess perchlorate concentrations in commercially available powdered infant formulas (PIFs). Secondary objectives were: (1) to estimate exposure in infants under different dosing scenarios and compare them with the perchlorate reference dose (RfD); (2) estimate the perchlorate concentration in water used for preparing PIFs that would result in a dose exceeding the RfD; and (3) estimate iodine intakes from PIFs. We quantified perchlorate levels in three samples (different lot numbers) of reconstituted PIF (using perchlorate-free water) from commercial brands of PIF in each of the following categories: bovine milk-based with lactose, soy-based, bovine milk-based but lactose-free, and elemental (typically consisting of synthetic amino acids). Exposure modeling was conducted to determine whether the RfD might be exceeded in 48 dosing scenarios that were dependent on age, centile energy intake per unit of body weight, body weight percentile, and PIF perchlorate concentration. We obtained three different samples in each of the five brands of bovine- and soy-based PIF, three different samples in each of the three brands of lactose-free PIF, and three different samples in two brands of elemental PIF. The results were as follows: bovine milk-based with lactose (1.72 mug/l, range: 0.68–5.05); soy-based (0.21 mug/l, range: 0.10–0.44); lactose-free (0.27 mug/l, range: 0.03–0.93); and elemental (0.18 mug/l, range: 0.08–0.4). Bovine milk-based PIFs with lactose had a significantly higher concentration of perchlorate (P<0.05) compared with all. Perchlorate was a contaminant of all commercially available PIFs tested. Bovine milk-based PIFs with lactose had a significantly higher perchlorate concentration perchlorate than soy, lactose-free, and elemental PIFs. The perchlorate RfD may be exceeded when certain bovine milk-based PIFs are ingested and/or when PIFs are reconstituted with perchlorate-contaminated water.

A world-first breakthrough to treat high blood pressure has been successfully trialed in Melbourne.

Physorg.com/news, April 5, 2009 — Blood Pressure Above 160? –
If BP Meds Not Working, Explore New Investigational Device in Trial

The clinical trial showed significant improvement in blood pressure of participants who were given a new catheter-based treatment where blood pressure lowering medication had failed.

Director of Monash University’s Centre of Cardiovascular Research and Education in Therapeutics, Professor Henry Krum led the research collaboration between Monash, the Baker Heart and Diabetes Institute, and St Vincent’s Hospital to develop the new surgical technique that disrupts nerves around the kidneys to dramatically reduce high blood pressure.

The technique could benefit those at high risk of heart attack or stroke from high blood pressure that resists conventional drug treatments.

Professor Krum presented these data in a late breaking clinical trial session at The American College of Cardiology’s 58th Annual Scientific Session earlier this week and was lead author on a simultaneous publication in The Lancet.

The results are set to revolutionize high blood pressure treatment in patients around the world.

Professor Henry Krum said the treatment would benefit those five to twenty per cent of patients with high blood pressure who do not respond to medication.

“Patients who underwent the procedure had a significant reduction in their blood pressure levels and we were able therefore to reduce their risk of severe stroke or heart attack,” Professor Krum said.

A total of 50 patients were recruited from Australia and overseas for the trial conducted by a team of researchers, which included Professor Henry Krum, from Monash University, Professor Markus Schlaich and Professor Murray Esler from Baker IDI and Professor Rob Whitbourn from St Vincent’s Hospital, Melbourne.

Professor Krum said the trial results were the most significant in the treatment of high blood pressure since the introduction of the drugs that are in use today.

“We showed an excellent safety profile of this brief, catheter-based therapy. No long-term adverse events resulted from the procedure. Therapeutic renal denervation led to a large and persistent decrease in blood pressure, which was achieved in patients resistant to multiple existing hypertensive drug types. Moreover, reduction of blood pressure was evident as early as 1 month, was further reduced at 3 months, and persisted through subsequent assessments,” Professor Krum said.

The procedure is carried out under local anesthetic and uses radio energy frequency, delivered to the targeted nerve area via catheter. As a result the nerves are silenced in the renal artery, which supplies blood to the kidneys.

Researchers had long-believed that this region was a key regulator of blood pressure, but until these trial results the theory had not been successfully trialed.

“The catheter allowed us to target a very specific area to deliver the right amount of frequency to the nerves without damaging the surrounding areas,” Professor Krum said.

Source: Monash University, www.BloodPressureTrial.com

News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd

Medscape, April 6, 2009 — Four health behaviors combined predict more than a 2-fold difference in stroke incidence in men and women, according to the results of a population-based prospective study reported in the February 20 Online First issue of the BMJ.

“Lifestyle behaviours such as smoking, physical activity, and diet influence the risk of cardiovascular disease, including stroke,” write Phyo K. Myint, from School of Medicine, Health Policy and Practice, University of East Anglia, Norwich, United Kingdom, and colleagues. “Previously we looked at the combined impact of four health behaviours — smoking, physical activity, alcohol intake, and fruit and vegetable intake — on total and cause specific mortality in men and women living in the general community. As these health behaviours could beneficially affect the incidence of stroke we examined the potential magnitude of their combined impact on incidence of stroke in men and women aged 40-79.”

In the European Prospective Investigation of Cancer–Norfolk study, adults living in the general community in Norfolk, United Kingdom, were followed up to 2007. The study cohort consisted of 20,040 men and women aged 40 to 79 years with no known stroke or myocardial infarction when surveyed at baseline from 1993 to 1997. Participants were scored from 0 to 4, receiving 1 point for each of the following health behaviors: current nonsmoking; physically not inactive; moderate alcohol intake (1 – 14 units a week); and fruit and vegetable intake of 5 or more servings daily, as reflected by plasma concentration of vitamin C of 50 μmol/L or more.

Average follow-up was 11.5 years. During 229,993 person-years of follow-up, there were 599 incident strokes. Compared with people with all 4 health behaviors, the relative risks for stroke for men and women were 1.15 (95% confidence interval [CI], 0.89 – 1.49) for 3 health behaviors, 1.58 (95% CI, 1.22 – 2.05) for 2 health behaviors, 2.18 (95% CI, 1.63 – 2.92) for 1 health behavior, and 2.31 (95% CI, 1.33 – 4.02) for no health behaviors (P < .001 for trend), after adjustment for age, sex, body mass index (BMI), systolic blood pressure, cholesterol concentration, history of diabetes and aspirin use, and social class. Subgroups based on sex, age, BMI, and social class all had similar findings. Exclusion of deaths within 2 years also did not affect the observed pattern of results. "Four health behaviours combined predict more than a twofold difference in incidence of stroke in men and women," the study authors write. "These results provide further incentive and support for the notion that small differences in lifestyle can have a substantial potential impact on risk." Limitations of this study include possible reverse causality or residual confounding, potential measurement errors in the assessment of exposures, relatively high proportions of the population with some or all positive health behaviors, exclusion of approximately 9000 participants who consented to the study but were unable to attend the health check, and possible misclassification of stroke vs nonstroke. In an accompanying editorial, Dr. Matthew F. Giles, from the Stroke Prevention Research Unit, Biomedical Research Centre, John Radcliffe Hospital, Oxford, United Kingdom, notes additional limitations of the study, including failure to differentiate ischemic and hemorrhagic strokes, and use of vitamin C concentration only as a surrogate marker for fruit and vegetable intake. "It is encouraging that the association between the risk of stroke and combined health behaviour is consistent across different populations, and between observational and randomised controlled trials," Dr. Giles writes. "The conclusion that lifestyle predicts the risk of stroke should help to inform individuals' choices and policy makers' decisions. However, what is also consistent but less encouraging is the small proportion of participants with a lifestyle that protects against stroke — although lifestyle interventions could be of great benefit, a huge shift in behaviour will be needed to achieve this." European Prospective Investigation of Cancer–Norfolk is supported by research program grant funding from Cancer Research United Kingdom and the Medical Research Council, with additional support from the Stroke Association, British Heart Foundation, Research Into Ageing, Academy of Medical Sciences, and Wellcome Trust. The study authors and Dr. Giles have disclosed no relevant financial relationships. Clinical Context

Lifestyle behaviors such as smoking, physical activity, diet, and alcohol intake can influence cardiovascular risk, but the role of these behaviors in influencing risk in the general population is not well known. For example, other studies have reported a decrease in the incidence of myocardial infarction associated with reduction in cigarette smoking.

This is a longitudinal prospective cohort study to examine the impact of adherence to the modifiable behaviors and the risk for stroke in community-dwelling men and women in 1 region of the United Kingdom who were followed up in the European Prospective Investigation of Cancer–Norfolk study.

News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd

Medscape.com, April 3, 2009 — Drinking hot tea was strongly associated with a higher risk for esophageal cancer according to the results of a northern Iranian population-based case-control study reported online first on March 27 in the British Medical Journal.

“An association between drinking hot beverages and risk of oesophageal cancer has been reported in several studies from different parts of the world,” write Farhad Islami, MD, from Shariati Hospital, Tehran University of Medical Sciences in Iran, and colleagues. “In Golestan, tea and water are the only drinks commonly consumed, with comparable average intake. An ecological study showed that inhabitants of Golestan drank more tea and at a higher temperature than people living in a nearby area with a low incidence of oesophageal cancer.”

The goal of this study was to evaluate the relationship between characteristics of tea drinking habits in Golestan province in northern Iran, which is an area with a high incidence of esophageal squamous cell carcinoma (SCC), and risk for that disease. Patterns of tea drinking and temperature at which tea was usually drunk were also determined for healthy persons enrolled in a cohort study.

Tea drinking among 300 patients with histologically proven esophageal SCC was compared with that in 571 matched neighborhood controls in the case-control study and in 48,582 participants in the cohort study. The primary study endpoint was the odds ratio (OR) of esophageal SCC associated with drinking hot tea.

Regular drinking of black tea was reported by 98% of the cohort participants, with mean daily volume more than 1 L. Reported temperature of tea was less than 60°C in 39.0% of participants, 60°C to 64°C in 38.9%, and 65°C or higher in 22.0%. Reported temperature agreed moderately with actual temperature measurements (weighted κ, 0.49).

In the case-control study, risk for esophageal cancer was increased for drinking hot tea (OR, 2.07; 95% confidence interval [CI], 1.28 – 3.35) or very hot tea (OR, 8.16; 95% CI, 3.93 – 16.9) vs lukewarm or warm tea. Risk was also significantly increased for drinking tea 2 to 3 minutes after pouring (OR, 2.49; 95% CI, 1.62 – 3.83) or less than 2 minutes after pouring (OR, 5.41; 95% CI, 2.63 – 11.1) vs drinking tea at least 4 minutes after being poured. Responses to the questions about temperature at which tea was drunk agreed strongly with interval from tea being poured to being drunk (weighted κ, 0.68).

“Drinking hot tea, a habit common in Golestan province, was strongly associated with a higher risk of oesophageal cancer,” the study authors write.

Limitations of this study include possible information bias regarding the amount and temperature of consumed tea, validation study performed among healthy people, possible selection bias, and some missing data.

“A large proportion of Golestan inhabitants drink hot tea, so this habit may account for a substantial proportion of the cases of oesophageal cancer in this population,” the study authors write. “Informing the population about the hazards of drinking hot tea may be helpful in reducing the incidence of oesophageal cancer in Golestan and in other high risk populations where similar habits are prevalent.”

In an accompanying editorial, David C, Whiteman, from Queensland Institute of Medical Research at Royal Brisbane Hospital in Australia, recommends allowing tea to cool for 5 minutes before drinking.

“The mechanism through which heat promotes the development of tumours warrants further exploration and might be given renewed impetus on the basis of these findings,” Dr. Whiteman writes. “These findings are not cause for alarm, however, and they should not reduce public enthusiasm for the time honoured ritual of drinking tea. Rather, we should follow the advice … [that suggests] a five to 10 minute interval between making and pouring tea, by which time the tea will be sufficiently flavoursome and unlikely to cause thermal injury.”

The Digestive Disease Research Center of Tehran University of Medical Sciences, the National Cancer Institute, National Institutes of Health, and the International Agency for Research on Cancer supported this study. The study authors and Dr. Whiteman have disclosed no relevant financial relationships.

BMJ. Published online March 27, 2009.

Clinical Context

SCC of the esophagus is the most common type of esophageal cancer worldwide; in the West, it is associated primarily with smoking and alcohol consumption, with a higher incidence in men than women. However, in certain regions such as northern Iran and Linxian, China, with very high incidence of SCC of the esophagus, the consumption of hot tea has been linked to increased risk for esophageal SCC. The mechanism of carcinogenesis is believed to be thermal damage of the epithelium.

The study was a combination of a case-control and a cohort study to examine the association between the temperature at which tea was consumed and waiting time between making and drinking hot tea and to examine the link between consumption of hot tea and risk for esophageal SCC.

Blue Light Destroys Antibiotic-Resistant Staph Infection – Results Reported in Photomedicine…

NEW ROCHELLE, N.Y., www.liebertpub.com /PRNewswire/ — Two common strains of methicillin-resistant Staphylococcus aureus, commonly known as MRSA, were virtually eradicated in the laboratory by exposing them to a wavelength of blue light, in a process called photo-irradiation that is described in a paper published online ahead of print in Photomedicine and Laser Surgery. The article will appear in the April 2009 issue (Volume 27, Number 2) of the peer-reviewed journal published by Mary Ann Liebert, Inc. The paper is available free online at www.liebertpub.com/pho

Antibiotic-resistant bacterial infections represent an important and increasing public health threat. At present, fewer than 5% of staphylococcal strains are susceptible to penicillin, while approximately 40%-50% of Staph aureus isolated have developed resistance to newer semisynthetic antibiotics such as methicillin as well.

Chukuka S. Enwemeka, Deborah Williams, Sombiri K. Enwemeka, Steve Hollosi, and David Yens from the New York Institute of Technology (Old Westbury, NY) had previously demonstrated that photo-irradiation using 405-nm light destroys MRSA strains grown in culture. In the current study, “Blue 470-nm Light Kills Methicillin-Resistant Staphylococcus aureus (MRSA) in Vitro,” the authors exposed bacterial colonies of MRSA to various doses of 470-nm light, which emits no UV radiation.

The two MRSA populations studied–the US-300 strain of CA-MRSA and the IS-853 strain of HA-MRSA–represent prominent community-acquired and hospital-acquired strains, respectively. The authors report that the higher the dose of 470-nm blue light, the more bacteria were killed. High-dose photo-irradiation was able to destroy 90.4% of the US-300 colonies and the IS-853 colonies. The effectiveness of blue light in vitro suggests that it should also be effective in human cases of MRSA infection, and particularly in cutaneous and subcutaneous infections.

“It is inspiring that an inexpensive naturally visible wavelength of light can eradicate two common strains of MRSA. Developing strategies that are capable of destroying MRSA, using mechanisms that would not lead to further antibiotic resistance, is timely and important for us and our patients,” says Chukuka S. Enwemeka, PhD, FACSM, Co-Editor-in-Chief of the Journal and first author of the study.

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Revolutionary stem cell therapies could replace diseased body tissues, offering enormous promise for patients with incurable conditions such as Parkinson’s disease and diabetes. Stem cells are immature cells that can divide into various types of cells that make up the body’s different organs and tissues. At the 35th Annual Meeting of the European Group for Blood and Marrow Transplantation (EBMT), Prof. Katarina Le Blanc (Karolinska Institute, Stockholm, Sweden) chaired a session in which researchers discussed how stem cell therapy could regenerate other body tissues, thereby greatly improving human health and quality of life.

Regenerative medicine aims to treat currently incurable disorders, including neurodegenerative diseases such as Parkinson’s disease a devastating condition affecting around 6.3 million people worldwide. Regenerative medicine may also be used to treat muscular dystrophy and multiple sclerosis, and to repair or replace nerve cells (or ‘neurons’) damaged by spinal cord injury.

Regenerative medicine also has potential to generate new insulin-producing cells in people with diabetes. Around the world, 180 million people have diabetes and the condition contributes to 1-3 million deaths a year through complications such as heart disease and strokes. People with diabetes are unable to produce sufficient insulin, a hormone that helps control blood sugar levels, because of defects in the insulin-producing cells in the pancreas. Regeneration of these insulin-producing cells could offer a groundbreaking new approach to diabetes therapy.

Other uses of regenerative medicine include the growth of new cardiac muscle cells for patients who have suffered from heart attacks.

Stem cell therapy may either work by providing new stem cells to the patient or by stimulating growth of the patient’s own stem cells. Scientists have recently learned a great deal about how stem cells contribute to the regeneration of tissues in the human body after birth.

Dr Kirsty Spalding and co-workers (Karolinska Institute, Stockholm, Sweden) aged brain neurons by measuring levels of radioactive carbon-14, generated by nuclear bomb tests during the Cold War, in people’s DNA. Neurons in the brain’s cerebral neocortex are as old as the individual, i.e. these cells are only generated around the time of birth and not in adulthood. This means that the body has cannot normally replace these cells if they are damaged or diseased.

Bone marrow ‘stromal’ stem cells are able to differentiate into various types of tissue that form the skeleton, including bone and cartilage. Prof. Paolo Bianco (“La Sapienza” University, Rome, Italy) and co-workers have shown that stromal cells may be used to reconstruct bone, for example in the reconstruction of the face in with patients with injuries.

Experiments conducted by Prof. Yair Reisner and co-workers (Weizmann Institute, Rehovot, Israel) suggest that it in the future it may be possible to grow new organs such as the liver by transplanting stem cells from one individual to another.

Stem cell research and regenerative medicine are rapidly developing research areas, and considerable hope is placed on the use of stem cells in medicine to repair tissue for diseases that are currently not curable.

What kind of security policies do you enforce on mobile devices and smartphones that employees bring into the office? Are unsecured mobile devices opening up a backdoor into your corporate network?

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TechRepublic.com, April 6, 2009, by Paul Mah — A study conducted by Credant Technologies shows that the use of mobile phones or devices for work-related matters is on the upswing. In a manner, this is surely good news, since what it means is that workers are increasingly being able to maximize their time – especially since shipments of smartphones have been projected to continue increasing.

Some of the statistics from the survey are as follows:

· 35 percent receive and send business e-mail

· 30 percent use them as a business diary

· 17 percent download corporate information, such as documents and spreadsheets

· 23 percent store customers’ information

In all, 600 commuters were interviewed at London railway stations. Interestingly, while 99 percent use their personal phones for some sort of corporate use or other, a quarter of them have actually been asked by their employer not to do so. The reason for that is simple enough – the possibility of losing one’s mobile phones to theft or carelessness could open the way to devastating data leaks.

In addition, unlike laptops where information stored is usually limited to whatever is on the hard disk, mobile devices are increasingly equipped and configured to tap into storage repositories and databases inside the corporate network.

The use of unsecured mobile devices

What I thought to be of particular concern here is the fact that 40 percent surveyed in this random sample failed to protect their mobile phones with even a rudimentary password. Extrapolating from this lack of security consciousness, the contents of media cards itself are likely to be similarly unprotected. I would not be surprised if the percentages of users without password or encryption were similar elsewhere.

The glaring problem here is that most mobile phones and many smartphones do not have inherent support for the security controls necessary for an enterprise lock-down. Various solutions are available depending on the mobile platform used, with the RIM BlackBerry and Microsoft’s Windows Mobile leaving the rest pretty much in the dust at the moment. Of course, a BlackBerry or Windows Mobile smartphone that is not configured – or improperly configured – remains unsecure.

To fill the gap for other platforms such as Palm OS and Nokia’s S60, a number of third-party applications that provide security controls for them do exist. One such example would be Good Technology’s Good for Enterprise application suite. Recently acquired by Vosto, the software suite – among other features – brings enterprise device management and security to a number of platforms and has native clients for Windows Mobile, Palm, and Symbian S60 devices. Yet other solutions would be Sybase iAnywhere or DataViz RoadSync. The caution here is that these are not specifically created to implement security, though they do offer some form of limited encryption (iAnywhere), or remote device wipe (RoadSync).

Whatever the approach, a deliberate strategy needs to be put into place to eliminate the presence of unsecured mobile devices able to access the corporate network.

The absence of a mobile usage policy

While computer usage policies are common in organizations by now, the situation is different when it comes to policies pertaining to the usage of mobile devices. As it is, mobile usage policy needs to be in place, to be followed by the implementation of security controls. This is hardly as easy as it appears to be, since these controls have to span the entire organization hierarchy in order to be effective. In addition, loss remediation procedures need to be drawn up and made known.

Finally, another obvious action would be to educate all staff of the security and legal implications of downloading sensitive information to their own personal and corporate phones. An altogether more draconian approach would be to forbid employees to use their own phones for corporate purpose – though its effectiveness is questionable unless corporate devices are furnished by the company.

In conclusion, mobility is expanding the corporate network far beyond the boundaries of the enterprise firewall. CIOs and administrators need to give a lot more thought into what needs to be done to address this enlarged network, and get on with it quickly.

Paul Mah is an independent tech writer, covering a range of topics from enterprise IT to mobile technology. Several times a week, he also indulges in teaching IT-related topics at a local polytechnic. You can reach him via his contact page at TechatPlay.com.