Undoing the Damage of Glaucoma

by Greg Miller 

In people suffering from glaucoma, damage to the optic nerve can slowly degrade peripheral vision and, in the worst cases, eventually lead to blindness. But eyedrops containing nerve growth factor (NGF)--a protein that promotes the survival and growth of neurons in the developing brain--appear to prevent nerve damage in rats and restore some vision in three human glaucoma patients, the authors of a new study claim. Not everyone thinks the reported effect is real, however.

For the study, ophthalmologist Alessandro Lambiase of the University of Rome Campus Bio-Medica and colleagues first mimicked glaucoma in rats. The researchers recreated the most common form of the disease, in which increased fluid pressure inside the eye damages nerves, by injecting saline solution into a vein in the eye. They kept the intraocular pressure up for 7 weeks, killing about 40% of the neurons in the retina whose tail-like axons give rise to the optic nerve, which conveys visual information to the brain. However, in rats treated four times daily with NGF-laced eyedrops during the 7-week period, the death of these "retinal ganglion cells" was reduced by about 25%, the team reports online today in the Proceedings of the National Academy of Sciences. (The senior author on the paper is neuroscientist Rita Levi-Montalcini, who shared the 1986 Nobel Prize in physiology or medicine for the discovery of NGF and in April became the first Nobelist to celebrate a 100th birthday.)

Encouraged by these findings, the researchers asked three patients with advanced glaucoma to take the drops four times daily for 3 months. Peripheral vision, one of the main visual functions impaired by glaucoma, improved in two of the patients and got no worse in the third, the researchers report in the same paper. They also report improvements in visual acuity, contrast sensitivity, and in electrophysiological measures of nerve conduction in the visual system in some or all of the patients.

Experts are divided over the findings. "It's very significant if it's real," says Richard Libby, a glaucoma researcher at the University of Rochester in New York state. Other compounds have been shown to have a similar protective effect on rat retinal cells when injected into the eye, Libby says, but the possibility of delivering a neuroprotective drug in eyedrops is "very exciting."

But Harry Quigley, an ophthalmologist and glaucoma researcher at Johns Hopkins University in Baltimore, Maryland, isn't buying any of it. Quigley faults the study's methods, including the lack of human control subjects and the design of the human experiments. Visual field measurements are notoriously susceptible to placebo effects, Quigley says, and because subjects knew they were getting the real treatment, he thinks it's possible the improvements in peripheral vision were due to raised expectations rather than the drug itself.

New Data Spark Retraction Request for Chronic Fatigue Virus Study

by Jon Cohen 

You cannot un-ring a bell, but you can retract a scientific study. Then again, as a raging debate over a Science paper that linked a mouse retrovirus to chronic fatigue syndrome (CFS) makes clear, retractions can be a tall order, too.

In conjunction with their decision to publish two additional papers that strongly question the link between the virus, known as XMRV, and CFS, editors at Science last week privately requested the retraction of the study that 2 years ago first made this connection. Replying on behalf of the original paper's authors, Judy Mikovits of the Whittemore Peterson Institute for Neuro-Immune Disease in Reno, Nevada, yesterday declined the request in a letter to Science, calling the action "premature." Today, after The Wall Street Journal published leaked details of the exchange, Science released online the two new papers along with an Editorial Expression of Concern about the 2009 paper written by Editor-in-Chief Bruce Alberts.

On 26 May, Alberts and Executive Editor Monica Bradford wrote Mikovits and noted they were "extremely concerned" about the validity of the original paper given "the growing number of research papers from independent investigators who have either failed to replicate your original finding that XMRV is associated with chronic fatigue syndrome and/or who have provided evidence that laboratory reagents are widely contaminated with the virus." They asked Mikovits and her co-authors to voluntarily retract their paper, known as Lombardi et al., writing that "it would be in the best interest of the scientific community." CFS patients, who have no treatment for their baffling condition, have paid intense attention to the XMRV findings with some already taking antiretroviral drugs marketed to combat HIV.

Mikovits, who supplied the Science letter and her subsequent responses to ScienceNOW, says the retraction request "came out of nowhere" late on Thursday afternoon before a holiday weekend and did not include the new papers Science planned to publish. "We were all just pretty well stunned," she says, noting that all but one of the co-authors of the original paper joined a conference call Friday morning and agreed not to retract. In her 30 May letter to Alberts and Bradford, Mikovits wrote that she and her co-authors shared the "deep concern" over the number of studies that have not been able to replicate their findings. But she warned that publishing the expression of concern would have a "disastrous impact on the future of this field of science" and maintained that their original report that found evidence of the virus in 67% of CFS patients and only 3.7% of controls was accurate.

The two new papers published online by Science today both point to contamination as the most likely explanation for the results from Mikovits's 2009 paper and from one other high-profile report that found a link between CFS and XMRV-related mouse retroviruses. One study, led John Coffin of Tufts University in Boston and Vinay Pathak of the U.S National Cancer Institute in Frederick, Maryland, describes how laboratories in the 1990s accidentally created XMRV while working with mice and a human prostate tumor to make an immortalized cell line to study prostate cancer. The first reports of XMRV came in 2006 from labs studying prostate cancer. The links to that disease are now in question, too. (ScienceNOW reported on Pathak's presentation of his origin findings at a meeting in March.)

Retrovirologist Jay Levy of the University of California, San Francisco, headed the group behind the second paper released today, which failed to find XMRV in 61 patients who had confirmed diagnoses of CFS. Although other studies have not found XMRV in CFS patients, this one included 43 people who were notified earlier by Mikovits's group that they were infected with the virus. The researchers further showed that mouse retroviruses routinely contaminate many commonly used lab reagents. "The net is really closing around" the 2009 paper, says Jos van der Meer of Radboud University in the Netherlands, who pointed out several shortcomings in the study in a 2010 comment in Science and whose own study of 32 Dutch CFS patients failed to find any trace of XMRV.

Mikovits says neither of the new studies undermines her group's original report. Anyone who reads the new papers, she asserts, will conclude that they "have nothing to do with Lombardi et al." The original study only speaks to labs that have used a specific prostate cancer cell line or its derivatives, she contends. As her letter to Alberts and Bradford explains in detail, the human cell lines in her group's lab repeatedly tested negative for XMRV, and they have no mouse lines. As for the Levy study, Mikovits insists that her team carefully controlled for contamination of reagents. She also claims the work fails to faithfully replicate their methods. "They didn't do one thing we did," she says. Levy disagrees, saying, "We did it exactly the way they did it."

Jonathan Stoye, a retrovirologist at the MRC National Institute for Medical Research in London who co-authored a perspective in Science supportive of the original work when it first appeared, now believes that contamination explains those results. He says Mikovits and her team have offered "an endless succession" of criticisms about the way other labs have conducted studies. "This isn't a conspiracy against them: Tens of labs have tried to reproduce their findings without success," Stoye says. "There are some very smart people in this, and they would not have got this wrong. It's an insult to us all. My lab will not do any more XMRV research."

Stoye may be abandoning the topic, but two multilab studies organized by the U.S. National Institutes of Health are now evaluating blinded blood samples from CFS patients and controls to determine whether XMRV indeed has links to the disease. Mikovits's team is participating, and results are expected by the end of the year. "Science eagerly awaits the outcome of these further studies and will take appropriate action when their results are known," concludes Alberts's expression of concern.

Farming Conquered Europe at Least Twice

by Michael Balter 

The rise of agriculture in the Middle East, nearly 11,000 years ago, was a momentous event in human prehistory. But just how farming spread from there into Europe has been a matter of intense research. A new study of ancient DNA from 5000-year-old skeletons found in a French cave suggests that early farmers entered the European continent by at least two different routes and reveals new details about the social structures and dairying practices of some of their societies.

Scientists studying the spread of farming into Europe have numerous questions: Was agriculture brought in primarily by Middle Eastern farmers who replaced the resident hunter-gatherers? Or did agriculture advance through the spread of technology and ideas rather than people? And was there just one wave of farming into the continent or multiple waves and routes?

Until recently, researchers had to rely on the genetic profiles of modern-day Europeans and Middle Easterners for clues. Numerous such studies, especially of Y chromosomes, which are transmitted via the paternal line, suggest that actual farmers, not just their ideas, spread westward over the millennia, eventually reaching the British Isles. Yet other studies, based on mitochondrial DNA (mtDNA), which is inherited maternally, have come to the opposite conclusion, suggesting that farmers had local European ancestry.

Now, new studies have begun to resolve these issues by sequencing the DNA of the prehistoric farmers themselves. Some of this research, most notably in Germany, suggests that male farmers entering central Europe mated with local female hunter-gatherers—thus possibly resolving the contradiction between the Y chromosome and mtDNA results.

The new paper, published online this week in the Proceedings of the National Academy of Sciences, backs up that idea. A team led by molecular anthropologist Marie Lacan of the Paul Sabatier University in Toulouse, France, reports work on ancient DNA—both mitochondrial and Y-chromosomal—from more than two dozen skeletons found in the 1930s in a cave called Treilles in southern France. Archaeologists think Treilles is a communal grave site because the bones add up to 149 individuals, 86 adults and 63 children. The team took DNA in such a way as to ensure that each individual was sampled only once (using teeth that were still attached to a lower jaw) and was able to obtain ancient DNA from 29 people.

They found that the female and male lineages seemed to have different origins. The mtDNA showed genetic markers previously identified as having deep roots in ancient European hunter-gatherer populations, but the Y chromosomes showed the closest affinities to Europeans currently living along the Mediterranean regions of southern Europe, such as Turkey, Cyprus, Portugal, and Italy. The team concludes that, in addition to the spread of farming into Central Europe suggested by the German studies, there appears to have been at least one additional route via southern Europe.

The communal grave also yielded additional intriguing details about these ancient Europeans. Most of the skeletons were males, and many appeared to be very closely related: At least two pairs of individuals were almost certainly father and son, and another pair were brothers. That suggests that the incoming male farmers established a so-called patrilocal society, in which the men stay put on their land but mate with women who come in from surrounding regions, the team concludes.

The study also showed that, in contrast to ancient DNA findings from central Europe, the people from Treilles lacked a key genetic variant that allows the body to digest lactose into adulthood. That’s consistent with other archaeological evidence that central European farmers herded dairy cows, whereas Mediterranean farmers herded sheep and goats and drank fermented milk, which has much lower lactose levels.

Lounès Chikhi, a geneticist at Paul Sabatier University who has studied the spread of farming for many years, praises the team for getting both Y chromosome and mtDNA from the same skeletal collection. “We have been calling for exactly this kind of data,” Chikhi says, “so I am very excited.” Colin Renfrew, an archaeologist at the University of Cambridge in the United Kingdom, agrees that the findings support a second, southern European spread of farming. “They do indeed suggest a significant population influx from the Eastern Mediterranean.”

But Wolfgang Haak, a geneticist at the University of Adelaide in Australia, says that Treilles may be too young to provide reliable information about the spread of farming in southern Europe, which began at least 2000 years earlier. While these earlier migrations “should have left a genetic mark in later periods,” Haak says, Treilles might not be the “best candidate” for tracing them. The ancient DNA Lacan is now extracting from skeletons across France and Spain, Haak says, should provide more “piece[s] of the enormous puzzle we are trying to put together.”

Do Cell Phones Cause Cancer? An Explosive 'Maybe'

by Jennifer Couzin-Frankel 

Whether or not cell phones cause brain cancer is a question that's been debated (but not answered) for years, and today the World Health Organization (WHO) stepped into the fray. A WHO committee that evaluates various potential cancer-causing agents concluded that radiofrequency electromagnetic fields, including cell phones, are "possibly carcinogenic" to people. The announcement was seized upon and published in dozens of news outlets within minutes.

The International Agency for Research on Cancer (IARC) arrived at the conclusion of possible carcinogenicity after an 8-day review of the literature by 31 experts, in Lyon, France. The classification falls in the middle of IARC's hierarchy of risk, joining a group of more than 250 potential carcinogens that also includes lead, engine exhaust, and occupational exposure to dry cleaning. In a sign of how tough it is to determine that something doesn't cause cancer, just one of the 900 or so agents that IARC has evaluated, caprolactam, a component of fibers and plastics, falls in the "probably not carcinogenic" category.

When it comes to cell phones, "we found some threads of evidence telling us how cancer might occur, but I think there are acknowledged gaps and uncertainties," said Jonathan Samet, chairperson of the IARC Working Group and a physician and public health expert at the University of Southern California in Los Angeles, during a press conference. The working group was particularly influenced by an international study called Interphonethat's examining whether exposure to radiofrequency electromagnetic fields from cell phones causes cancer. Last year, the Interphone study group wrote in the International Journal of Epidemiology that it saw "no increase in risk of glioma or meningioma." It continued: "There were suggestions of an increased risk of glioma at the highest exposure level, but biases and errors" make it tough to show that the phones were the cause. "The possible effects of long-term heavy use of mobile phones require further investigation," they concluded.

IARC would like more research as well. Samet noted that at this point there are almost 5 billion cell phone subscriptions worldwide, and "we anticipate an ever larger population that is exposed for longer and longer." That said, shifting cell phones from the "possible" category to a more definitive one won't be easy. Epidemiologic studies like Interphone tend to match healthy people with those who have brain cancer and ask both to recall their cell phone use. "We know that is inherently imperfect," said Samet. And because all these studies take time to conduct, they inevitably examine older technology. Animal studies looking at the risk from radiofrequency electromagnetic fields have been mixed, both in whether they see a danger and in why that might be.

Whether IARC re-evaluates cell phone hazards, the committee says, will depend on what new research comes out.

SUGGESTED REFLEXES FOR EMPHASIS IN SPECIFIC DISORDERS

SUGGESTED REFLEXES FOR EMPHASIS IN SPECIFIC DISORDERS Anemia : Spleen/Lymph nodes and drain. Angina pectoris : Heart/Chest?Shoulder/Adrenals/Top of Left Foot. Arthritis : Top and bottom of Whole foot/Kidney/Adrenals/Pituitary/Solar. Asthma : Adrenals/solar/Lungs/Ileocecal Valve/Diaphragm/Bronchial area. Colitis : Colon/Solar/Adrenals. Cough and Cold : Sinus/Ileocecal Valve/Colon/Bronchial area.

Diabetes : Pancreas/Pituitary/Thyroid/Liver/Adrenals. Fainting : Pituitary/Whole Big toe. Female Disorders : Uterus/Ovary/Fallopian Tubes. Fever : Pituitary/Lymph nodes/Lymph drain. Flatulence (Gas in stomach or intestine) : Sigmoid/Solar/Intestines/Stomach. Heart troubles: Heart/Lungs/Adrenals/Sigmoid/Kidney/Stomach/Parathyroid. High Blood Pressure : Solar/Adrenals/Kidneys. Numbness in Fingers: 6th, 7th Cervicals/Solar/Shoulder/1st and 2nd Thoracic in Spine reflex. Paralysis: Top of toes and Fingers/shoulders/Knee and Hips/Total length of spine reflex. Phlebitis (Inflammation due to blocked vein) : Liver/Adrenals/Treat Part of Arm Corresponding to affected part of leg. Psoriasis: Thyroid/Adrenals/Pituitary/Kidney/Lymph nodes and drain. Sciatica: Sciatic/Lymph/Lower back/Knee-Hip/Sacral part of Spine reflex. Swellings:Top surface of whole foot/Lymph/Kidney/Ureter/Bladder/Pituitary. Varicose Veins: Liver/Colon/All Glands/Lymphatic System. Vertigo: Eyes/Ears/Lymph/Head/Cervical part of Spine reflex/Top and Bottom of webs between last 3 fingers. Ulcer: Stomach/Solar/Diaphragm/Adrenals/Liver. Urinary trouble: Kidneys/Ureter/Bladder/prostate.

ACUPRESSURE THERAPY

ACUPRESSURE THERAPY It is a way to health by a technique of applying direct pressure with fingers, thumb or palms of hand, over certain key-points over the body. Proper circulation of blood to even the remotest part of body is essential to keep body free from congestion and ailments. Circulation is life, stagnation is death. This therapy stimulates blood circulation by relieving congestion n nerve ending and muscles. Four different systems of treatment can be included under acupressure therapy : (1) Zone therapy (2) Foot reflexology (3) Shiatsu therapy (4) Meridian Points therapy. Zone Therapy In this Therapy, our body is assumed to be longitudinally divided into 5 zones on the right and 5 zones on the left side of the central line of the body, vertically. All parts of the body in the same zone are inter-related in such a way that any problem somewhere in a particular zone could be treated by pressure massage at some other area in that same zone. Foot Reflexology In this method, blood circulation in a particular organ in the body can be stimulated by pressure-massage at certain areas on the bottom, top or sides of the foot. Feet are a sort of switchboards, with different switches connected with the various organs of the body. A type of remote control. Due to excess acid condition in our blood stream, frost-like acid crystals are formed in the nerve endings in the feet. They obstruct the normal blood circulation to the related organ. Pressure massage over certain areas (called Reflexes) on the feet, breaks and loosens, as well as clears these crystals, thereby restoring the normal blood circulation to the organ involved. The dislodged crystals are carried away by the blood gradually and the acid is thrown out of the body through kidneys. Pain felt at reflexes on foot during the massage is due to these crystals getting crushed there. Identical reflexes as on the foot, are located on the hands also. But it is found more effective to treat the foot reflexes because the foot has a larger area and generally it is more protected than the hand, therefore tenderness (pain) of the reflexes is more noticeable in the foot than in the hands. Shiatsu Therapy This is a type of local points pressure treatment. Pressure points spread over the affected region of the body are to be treated for cure. Movement of body is caused by contraction of muscles. Energy for contraction of muscles is produced by a substance called Glycogen (a product from liver). When it combines with oxygen from lungs, combustion generates energy for muscular contraction. This produces a residue, called lactic acid. When sufficient quantity of lactic acid accumulates in the muscles, the contraction becomes difficult or impossible. By applying digital pressure over such muscles, 80% of the acid is reconverted into glycogen, thus relieving the muscle of the acid. This eleminates fatigue, improper muscular contraction and illness. Meridian Points Therapy According to a concept, human body has an internal network of about 14 channels (called meridians) located deep in the body, through which the energy flows. There are about 365 points over the body where these channels surface into the skin. Different ailments are caused when the balance of energy flowing through different meridians is upset or disturbed due to blockage of flow at some points. By treating with pressure massage these meridian points surfacing on skin, the blockage is removed resulting in the normal flow of energy again. This restores the balance of flow in all meridians and thereby, the ailment is cured. The point to be treated may not be necessarily over the affected region, it can be very far from the affected region. In this booklet, we have not discussed Meridian Points in details. Acupressure therapy is a harmless way of treatment, but very often producing miraculous results. It has been recognized by many Governments abroad and is being practiced in countries like China, Japan, America, Europe, Russia etc. There the Acupressure therapists and the Physicians work in co-operation.

Foot Reflexology Shiatsu Therapy Hand Reflexology Specific foot reflex points Important glands Urinary and Respiratory System Digestive System Circulatory and Lymphatic System Nervous System Some useful hints Dis-location of abdominal nerve center Suggested reflexes for emphasis in specific disorders

Why Apple is Doomed

The Motorola Xoom has more memory than the iPad 2. It has a larger and higher-resolution display. And it runs flash. Venerable tech blog Engadget reportedthat "it outclasses the iPad in many ways."

Before launch, Motorola unleashed a heavy media campaign, making obvious their intent to attack the market leader. In a $5 million spot during last year's Super Bowl, Motorola mimicked Apple's famous "1984" commercial by depicting a lone Xoom-toting yuppie surrounded by white-robed Apple acolytes.

In a way, the ad was right: Nobody uses a Xoom.

Motorola's optimistic estimate put sales around 200,000 units in two months. Apple's iPad 2, meanwhile, sold a million in its first weekend.

It was a remarkably easy outcome to predict. The Xoom was typical of Apple's competition: feature-packed but unpolished. Noted gadget pundit Jon Geller wrote that "It's almost as if Google decided to try and pack as much in as possible to advance the tablet category forward... I'm not sure it has succeeded." The iPad didn't have quite the feature set, but it didn't matter. As usual, Apple won through design.

While they do make superior hardware, their secret sauce is interface design. Apple consistently develops interfaces so intuitive that instructions would seem silly. Even toddlers can navigate the iPhone effectively. Their products simply make sense, in a way their competitors seem unable to match. Because of this unique advantage, Apple has achieved their greatest success creating mobile devices, where the interface is psychologicallycloser to the user.

Since releasing the iPod, Apple has dispatched challengers with Jedi-like ease, brushing aside giants and upstarts alike to become the most valuable tech company in the world. In the meantime, they've built a giant fanbase whose love for the company borders on the religious. The Apple advantage is good taste, and the originator of that taste is CEO Steve Jobs.

"Apple is the most design-savvy company in the world, and it's because of Steve," says Ray Riley, a former Apple designer. Jobs is a brilliant marketer and the company's visionary. But his most important role is as tastemaker.

Longtime Apple engineer Mike Evangelist was once tasked with heading the design of a DVD burning program for the Mac. His team developed dozens of sophisticated mock-ups and gathered to present them to Jobs. "He picks up a marker and goes over to the whiteboard," remembers Evangelist, "He draws a rectangle. 'Here's the new application,' he says. 'It's got one window. You drag your video into the window. Then you click the button that says BURN. That's it. That's what were going to make.'"

According to Inside Apple, Jobs holds court every Monday, reviewing each product under development at the time. The company's image is also under his constant scrutiny: he once demanded that a slab of Italian marble for Apple's SoHo store be shipped to him first for inspection. He is Apple's filter, personally ensuring that his stringent design standards are met across the board.

But Jobs is suffering from pancreatic cancer and is currently on his third leave of absence since 2004. Ever secretive, he keeps his condition tightly guarded. But he admitted in 2009 that "my health-related issues are more complex than I originally thought."

While Apple has fared well during his leaves, they are not a proper indicator of what the company would be like without him. While off-campus, he continues to exert a huge influence (he remained CEO during his most recent absence), and his legacy is fresh.

His management, even his vision, is replaceable. But that brilliant sense of taste, to which Apple owes their success, will not be matched by the next regime. His death would leave Apple closer to the pack than ever.

When that edge is gone, Apple will no longer be able to operate as they have become accustomed. Without vastly superior products, their arrogant marketing will fall on deaf ears. Consumers will consider alternatives more readily. Their prickly policies towards developers will take a toll.

The company is keenly aware of this weakness, and preparations are well underway. They have even commissioned an all-star team of business professors to write a series of case studies chronicling critical decisions in the life of Apple, hoping to groom young executives who can seamlessly step in were the worst to happen. But in Jobs, they posses the most valuable creative mind in the world. Apple is not just the latest great tech company, it is historically great, and to maintain that level without the irreplaceable taste of Steve Jobs will be impossible.

Ty Fujimura

Creative Director at Designer Pages, Design Entrepreneur

 

Startup Hopes to Make Sickness Social

Tracking sickness: A startup called Sickweather hopes to help users see which illnesses are going around, and if any of their friends have fallen ill.
Credit: Sickweather

WEB

Startup Hopes to Make Sickness Social

Social networking data could give clues to outbreaks of disease.

If a close friend has a cold, chances are you might catch it. A startup called Sickweather hopes to tap into the social side of sickness with a social networking service that tracks illnesses within a user's circle of friends, and to forecast outbreaks.

The startup mines publicly available data from social networks such as Twitter and Facebook, as well as from its users, to provide information on illness trends. Sickweather recently launched an early version of its site for closed beta testing, and plans to open to a broader audience in July.

While some people complain about the vast quantities of often mundane data uploaded to social networks every day, companies are increasingly interested in mining that information for commercial ends. Bluefin Labs, for example, uses social network data to determineusers' reactions to television shows and advertisements. Specialized social networks are also springing up to collect more precise data.

PatientsLikeMe, for example, is a social networking site on which patients can share information and experiences related to their condition.

Sickweather's founders hope the data they collect can help users avoid catching their friends' bugs. Users would be able to log in to the site and view a map showing illnesses in their area. They would also see updates from friend connections mentioning current illnesses. The company plans to release mobile apps for the site as well, so that users can view this information while on the go.

Graham Dodge, the company's CEO, says he thinks Sickweather will be particularly useful to young families that want to be alerted to illnesses going around their social circle. "They can decide, 'Maybe I won't take my kids to that birthday party,' " Dodge says. Users might also be able to use the information to decide whether their symptoms match up to current common illnesses and merit more attention, or to prepare a health regimen before taking a trip.

Like any social network, much of the value of Sickweather will depend on getting enough people to sign up, but the founders hope to provide a useful service based on publicly available data on social networks as well.

Sickweather uses Twitter's API to find information about sicknesses tied to a particular location. Michael Belt, Sickweather's chief technology officer, says the company searches for keywords related to sickness. To tune the algorithm, the system uses a database of words that exclude certain posts. For example, the system would want to record a post that says, "I'm feeling so sick—my nose is running." But it would exclude a post that says, "There were some sick beats last night at the club."

Sickweather hopes to eventually use posts that simply mention the symptoms of an illness. But the initial version of the site is focused on words such as "bronchitis," "pneumonia," and "pertussis." "It was eye-opening to see how much data we got just from specific technical terms," says Dodge.

Dodge says the company is exploring advertising partnerships to gain revenue for the site.

Others are exploring mining social networks for public health data, and their experiences show how difficult it can be. For example, HealthMap, cofounded by Clark Freifeld and John Brownstein, brings together data from a variety of sources to show outbreaks as they happen around the world. HealthMap began by crawling news reports and blogs, but also has a partnership with Google to mine data from search terms. The company offers apps for smart phones, Twitter, and Facebook, through which users can report outbreaks.

For HealthMap's purposes, Brownstein says, Twitter is a difficult source to mine. "You need a sizeable [health] event to get enough data," he says. For example, flu outbreaks are usually large enough to get sufficient posts from social networks, but gastric illnesses are too isolated, he says.

Gunther Eysenbach, a senior scientist in the division of clinical decision-making and health care at the Toronto General Research Institute, has extensively studied tracking diseases through the Internet. He says that data from social networks is full of false positives. For example, people may post about articles they've read about a disease, and it's hard to filter that out, he says.

Eysenbach also worries about the privacy implications. He says mining social connections could have a chilling effect on people's willingness to post about illness, since it could create uncomfortable social situations, such as when no one shows up to that kid's birthday party. Such an outcome, Eysenbach says, would be a shame, because such data has public-health value.