Thursday, 28 June 2012

Older Americans reporting fewer vision problems

Despite a general increase in health conditions like diabetes that can harm vision, Americans over 65 are about half as likely as their counterparts a generation ago to report having seriously impaired vision, according to a new U.S. study.

Using two large national surveys, researchers found the percentage of older adults who said they needed help performing daily tasks because of severe vision problems fell from 3.5 percent in 1984 to 1.7 percent in 2010. Those whose poor eyesight made it difficult to read or make out certain objects declined from 23 percent in 1984 to 10 percent in 2010.

"There are many possible explanations" for the significant decline in impaired vision said the study's lead author, Dr. Angelo Tanna, of the Northwestern University Feinberg School of Medicine in Chicago. "Improved techniques for cataract surgery may be a major driving force," he said.
Changes in nutrition and lifestyle over the decades may also be reducing the rates of other eye diseases, Tanna told Reuters Health in an email.

Previous research has linked reductions in the number of people who smoke to lower risks of vision loss due to macular degeneration, he explained. In addition, better glucose control among diabetics could lower the same risk for diabetic retinopathy.

The new study was published in the journal Ophthalmology.

Blindness or low vision affects 3.3 million Americans over age 40, according to the National Eye Institute. As the population ages, the number of Americans with major eye diseases is projected to increase substantially by 2020.

To gauge whether eye disease is indeed on the rise in older Americans, Tanna's team analyzed data from two large surveys, covering more than 100,000 adults, conducted yearly or every few years between 1984 and 2010.

Participants answered questions about problems related to their eyesight and how it affected their daily lives. One of the surveys focused just on severe vision impairments that limited a person's ability to perform basic functions, such as bathing or shopping, without help. The other survey asked about both severe impairments and less severe problems that interfered, for example, with seeing the letters in newsprint.

The researchers found little change in the rates of severe vision problems in middle-aged adults.
Among people over the age of 65, however, the number who said they needed help with daily activities due to poor eyesight declined by almost 46 percent in one survey and 59 percent in the other between 1984 and 2010.

When it came to less severe visual impairments, far fewer adults of all ages reported trouble in 2010 than in 1984. Over that period, the number of working age and older adults who struggled to read decreased by about 60 percent.

The research "illustrates the enormous advances in ophthalmology over the last 30 years," said Dr. James Tsai, chair of ophthalmology at Yale University School of Medicine in New Haven.
"People can regain vision right away after cataract surgery," he said. In other eye diseases, advanced treatments can stop or slow the progression of vision loss, he added.

As a result, "fewer people are going blind from diabetic retinopathy, glaucoma and macular degeneration," said Tsai, who was not involved in the new study.

In its report, Tanna's team noted that in addition to better therapies for eye diseases, "a more mundane contributing factor" may be the possible greater use of glasses and contact lenses or possibly even refractive surgery (such as Lasik).

Although study participants self-reported poor vision, which is less precise a measure of vision loss than a standardized eye exam, the survey findings reflect how the impairment affects daily lives, the authors remarked.

Future studies should further investigate what's behind the decrease in vision problems to identify the most effective strategies "to improve the health of the population and individuals' quality of life" they concluded.

SOURCE: Ophthalmology, online June 8, 2012.

Health Tip: Be a Dust Buster

Keeping your home as dust-free as possible goes a long way to preventing many allergy and asthma symptoms.
The American Academy of Pediatrics offers these suggestions:
  • Use a vacuum with a HEPA filter -- or vacuum when your child is out of the home -- to avoid worsening child allergy or asthma symptoms.
  • At least once weekly, mop hard-surface floors and wipe down furniture, blinds and decorations with a damp cloth.
  • During outdoor allergy season, keep windows closed and run the air conditioner.
  • Use a HEPA air cleaner in the home.
  • Use a dehumidifier to dry out the air and help prevent growth of mold.

Children exposed to HIV in the womb at increased risk for hearing loss

Children exposed to HIV in the womb may be more likely to experience hearing loss by age 16 than are their unexposed peers, according to scientists in a National Institutes of Health research network.
The researchers estimated that hearing loss affects 9 to 15 percent of HIV-infected children and 5 to 8 percent of children who did not have HIV at birth but whose mothers had HIV infection during pregnancy. Study participants ranged from 7 to 16 years old.
The researchers defined hearing loss as the level at which sounds could be detected, when averaged over four frequencies important for speech understanding (500, 1000, 2000, and 4000 Hertz), that was 20 decibels or higher than the normal hearing level for adolescents or young adults in either ear.
“Children exposed to HIV before birth are at higher risk for hearing difficulty, and it's important for them—and the health providers who care for them—to be aware of this,” said George K. Siberry, M.D., of the Pediatric, Adolescent, and Maternal AIDS Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the NIH institute that leads the research network.
Compared to national averages for other children their age, children with HIV infection were about 200 to 300 percent more likely to have a hearing loss. Children whose mothers had HIV during pregnancy but who themselves were born without HIV were 20 percent more likely than to have hearing loss. The study was published online in The Pediatric Infectious Disease Journal.
“If parents and teachers know the child has a hearing problem, then they may take measures to compensate in various communication settings, such as placement in the front of the classroom or avoiding noisy settings,” explained Howard Hoffman, M.A., director of the Epidemiology and Statistics Program at the National Institute on Deafness and Other Communication Disorders (NIDCD), which provides funding to the network for studies related to hearing and language.
Even a mild hearing loss in children can delay the acquisition of language skills. More severe hearing loss may require the use of assistive devices, such as a hearing aid. Information on hearing and deafness is available from NIDCD.
To determine the types of hearing loss the children experienced, the researchers conducted these evaluations:
  • Physical examination of the ear canal
  • Evaluation of the middle ear function, how sound vibrations are transmitted through the middle ear bones
  • Responses to tones presented over earphones
Hearing loss may occur from damage to the bones and structures in the ear canal and inner ear, or from damage to the nerves leading to the brain.

First author Peter Torre III, Ph.D., of San Diego State University, led the study with Hoffman, Siberry and six other coauthors. Collaborators were from the Harvard School of Public Health, Boston; the University of Kansas, Lawrence; and Tulane University School of Medicine, New Orleans.

The research was conducted as part of the Pediatric HIV/AIDS Cohort Study network, led by NICHD in cooperation with and with cofounding from NIDCD and several other NIH institutes, including: the National Institute on Drug Abuse, the National Institute of Allergy and Infectious Diseases, the National Institute of Mental Health, the National Institute of Neurological Disorders and Stroke, the National Heart Lung and Blood Institute, and the National Institute on Alcohol Abuse and Alcoholism.

More than 200 children and teenagers participated.  All had been exposed to HIV before birth, and about 60 percent were HIV-positive at the time of the study. Researchers conducted hearing tests on the children if their parents or caregivers had reported hearing problems, they had low scores on a standard test of language or their health care providers detected hearing problems during standard hearing screenings.

The researchers classified participants who could not hear tones below a certain volume as having hearing loss with difficulties in quiet and noisy settings. The researchers documented a greater proportion of hearing loss cases among HIV-positive children and found that those who had developed AIDS at any point were even more likely to have hearing loss—even if the disease was under control at the time of the study.

Earlier studies have found that children with HIV are susceptible to middle ear infections. Repeated middle ear infections can cause hearing loss. However, in 60 percent of cases in the study, hearing loss was the result of problems with the transmission of sound from the nerves of the ear to the brain, rather than to damage in the middle ear resulting from ear infections.

“Although ear infections are more common among children with HIV, these do not appear to be the reason their hearing is more likely to be compromised,” said Torre.

Three therapies may reverse action of new blood-thinning drug

Some of the therapeutic strategies that reverse the blood thinner warfarin may be effective with newer oral anticoagulants such as apixaban and rivaroxaban. The newer drugs require less frequent blood tests, have fewer interactions with foods and other medications and doses are less variable.
“Despite these advantages, there is one common side effect of all blood thinners that can be severe — excess bleeding,” said Gines Escolar, M.D., Ph.D., study author and associate professor of hematology at the University of Barcelona in Spain.
“If you have an accident or need emergency surgery, doctors have three ways to reverse warfarin that work in a matter of minutes to hours. In contrast, there is little information on how best to reverse the effects of newer anticoagulants, which can take 10-18 hours.”
Warfarin blocks vitamin K. So if excess bleeding occurs, the drug’s action can be reversed by administering the vitamin. When quick reversal is urgent with warfarin, other faster steps are sometimes taken. Researchers tested these steps in the preliminary study.
Blood clotting agents can potentially counteract the effect of blood thinners. In the lab, researchers added a high dose of apixaban (200 nanograms per milliliter) to blood from healthy donors. Then, they tested the blood-clotting response when three clotting agents were added: prothrombin complex concentrates (PCCs, 50 IU/kg), activated prothrombin complex concentrates (aPCCs, 75 IU/kg) and recombinant Factor VII (rFVIIa, 270 ug/kg). They found:
  • PCC and aPCC seemed more efficient than rFVIIa at restoring the generation of thrombin, an enzyme important in blood clotting.
  • rFVIIa was the quickest to produce a compact blood clot, followed by aPCC and PCC.
  • rFVIIa was most effective in studies with blood circulating through a damaged blood vessel, followed by PCC and aPCC.
“The good news is that the various lab tests applied indicate that these approaches may reverse the effects of apixaban,” Escolar said. “But, even with the favorable results in perfusion studies using a damaged vessel, we’re far from knowing what will work best in a bleeding patient. Resolving efficacy and safety issues will require a clinical trial.”
Apixaban is approved in Europe for preventing blood clots in adults after knee or hip replacement surgery. In the United States, a Federal Drug Administration application is under review for using apixaban to prevent stroke in people with atrial fibrillation.
Co-authors are: Eduardo Arellano-Rodrigo, M.D., Ph.D.; Juan Carlos Reverter, M.D., Ph.D.; Jaume Villalta, M.D., Ph.D.; Veronica Sanz, MLT ; Patricia Molina, MLT; Maribel Diaz-Ricart, Ph.D.; and Ana Maria Galan, M.D., Ph.D. Author disclosures are on the abstract.
Bristol-Myers Squibb partly funded the study.

First Stem Cell Vein Implant Helps Young Girl

In what is being reported as a scientific first, Swedish doctors were able pair the groin vein of a dead donor with stem cells from a young girl and implant the healthy vein into the girl, improving both blood flow in her lower body and her quality of life.

The 10-year-old had a rare condition where her portal vein, which is located in the abdomen and tasked with carrying blood from the bowels and other abdominal organs to the liver, was blocked. If this vein is blocked, liver disease, heart failure and certain cancers may develop. The relatively rare condition may also cause weight loss, nausea and pain.

Details of the feat are published online June 14 in The Lancet.

U.S experts were quick to caution that the procedure has only been accomplished in one patient, but they agreed that it could be a game-changer with applications that go far beyond this particular condition.

In the procedure, the transplant team from the University of Gothenburg in Sweden first took a segment of the groin vein from a dead donor, and stripped it of all living cells. They then injected stem cells taken from the girl's own bone marrow into the remaining vein. Two weeks after this seeding, the newly grown graft was implanted in the girl.

There were no complications, and the procedure immediately restored normal blood flow. In the year following the operation, the girl grew taller and gained weight. Her blood flow later decreased, and she underwent a second vein replacement surgery a year after the first. Her quality of life has improved since the procedures, and she is now able to take increasingly long walks and participate in light gymnastics. Importantly, she is showing no sign of rejecting the new vein even though she is not taking any immunosuppressive drugs.
"The new stem cells-derived graft resulted not only in good blood flow rates and normal laboratory test values but also, in strikingly improved quality of life for the patient," wrote the team led by Dr. Michael Olausson, of Sahlgrenska University Hospital in Gothenburg. "The work also establishes the feasibility and safety of a novel paradigm for treatment, in cases of venous insufficiency, obstructed veins or inadequate autologous [from the patient] veins."

Today, surgeons may approach such cases by harvesting veins from a patient's neck or leg to re-route around a blockage elsewhere. This can be traumatic and is associated with its own set of risks and complications. In addition, not everyone has healthy veins that can be used in this manner. This is where the new stem cell vein grafting procedure could play an important role.

"This is an interesting article and an exciting first step," said Dr. Scott Pilgrim, an attending pediatric cardiologist at Steven and Alexandra Cohen Children's Medical Center of New York, in New Hyde Park. "If this outcome turns out to be reproducible and is studied in a larger, defined population with a well-designed, controlled trial, I feel this advance could be a watershed moment in developing new, novel strategies for vascular and cardiothoracic surgeons."

The implications are far reaching in that new veins and arteries could be 'grown' ahead of time for an anticipated surgery, he said. "It would be interesting to see if these vessels are capable of continued growth in a child, as this is often the reason for re-operation in congenital heart disease." The grow-your-own approach may one day replace the need for mechanical heart valves and the use of blood-thinning drugs.

Donna Arnett, incoming president of the American Heart Association and chair of epidemiology at the University of Alabama at Birmingham, agreed that its potential is exponential.
"When you have to use an artificial graft, you worry about rejection and need to use immunosuppressant drugs," she said, and these drugs increase risk of developing infections. "This could be useful for people who don't have a vein to use from their own body, and it avoids the use of immunosuppressants."

They may also build on the concept and attempt to engineer arteries, which could be useful for people who require coronary artery bypass grafts to treat heart disease.
Challenges remain.

"A lot of lead time would be needed so this would not work in the situation where you need something acutely," Arnett said.

SOURCES: Scott M. Pilgrim, M.D., attending pediatric cardiologist, Steven and Alexandra Cohen Children's Medical Center of New York, New Hyde Park; Donna Arnett, Ph.D., incoming president, American Heart Association, and chair, epidemiology, University of Alabama at Birmingham: June 15, 2012, The Lancet

Clot-Busting Stroke Drug Safe for Many Who Take Warfarin

Many patients who've been taking the blood thinner warfarin can safely be administered the powerful clot-busting drug tPA in the event of a stroke, a new study shows.

The findings help ease previous concerns that tPA (tissue plasminogen activator) might be too dangerous to use in stroke patients who had been taking warfarin because it would increase their risk for potentially fatal bleeding in the brain.

Researchers at Duke University's Clinical Research Institute in Durham, N.C., analyzed data from thousands of stroke patients treated with intravenous tPA at more than 1,200 hospitals. While patients who were taking warfarin did have slightly higher rates of intracranial bleeding than those who were not taking warfarin (5.7 vs. 4.6 percent), they also tended to be older, the researchers noted.

So, after the researchers adjusted for age, stroke severity and other factors, they found that the risk of bleeding in the brain was similar for both groups of patients.

The team also found that nearly half of the warfarin-treated patients who might have qualified for potentially lifesaving tPA following a stroke did not receive the clot-busting drug.

The study was published June 26 in the Journal of the American Medical Association.

"To date, we have no randomized trials or large cohort studies to guide us," first author Dr. Ying Xian, an assistant professor of medicine, noted in a Duke news release. "Our large, national study found no statistically significant increase in risk, which supports using intravenous tPA in warfarin-treated patients following stoke if their INR is less than or equal to 1.7."

The INR (International Normalized Ratio) measures the rate at which blood clots while a patient is taking blood thinners such as warfarin, which is prescribed to reduce the risk of stroke in patients with a heart rhythm disorder called atrial fibrillation.

American Heart Association guidelines state that tPA can be used in warfarin-treated patients if their INR is less than or equal to 1.7.Experts were heartened by the results.

"This should be encouraging for those who treat acute stroke and hesitate when the INR is at all elevated," said Dr. Roger Bonomo, director of stroke care at Lenox Hill Hospital in New York City. "A patient presenting with stroke after taking warfarin is a 'warfarin failure' and deserves another chance at avoiding morbidity [illness/injury]."

Another expert called the research "important" because it provides guidance on when tPA use is safe and appropriate for patients taking warfarin, also known as Coumadin. "Many people take Coumadin who are at high risk of having a stroke, so it is important to know when giving tPA is beneficial to these patients," said Dr. Mark Stecker, chairman of neuroscience at Winthrop University Hospital in Mineola, NY.

SOURCES: Roger Bonomo, M.D., director, stroke care, Lenox Hill Hospital, New York City; Mark Stecker, M.D., chairman, neuroscience, Winthrop University Hospital, Mineola, N.Y.; Duke University, news release, June 26, 2012

Limited Use of Antibiotics OK for Dental Patients: Study

New U.S. guidelines recommending limited use of antibiotics in dental patients have not led to an increase in cases of the heart condition infective endocarditis, a new study says.

The number of cases has actually decreased since the American Heart Association guidelines were introduced in 2007, researchers found.

Infective endocarditis is a bacterial infection of the heart lining, valves or blood vessels. It can occur when bacteria enter the bloodstream through wounds in the gums that arise during invasive dental procedures such as a tooth extraction. Left untreated, the infection can cause death.
Previously, many patients received preventive antibiotics before having dental procedures. The new guidelines advised that patients take antibiotics before dental procedures only if they are at risk from infective endocarditis.

These patients include those with artificial heart valves, transplanted hearts with abnormal heart valve function, previous infective endocarditis, and specific heart defects.

In this study, researchers examined data from Olmsted County, Minn., and found 22 patients diagnosed with infective endocarditis between 1999 and 2010. Projected nationally, the researchers said the data suggests that infective endocarditis occurred in two to three of every 100,000 people in the United States before the new guidelines, and in one of every 100,000 after the new guidelines.
The researchers also found that the number of infective endocarditis cases diagnosed in the United States each year went from 15,300 to 17,400 in 1999-2006 to 14,700 to 15,500 in 2007-2009.
The study was published June 11 in Circulation.

"We were giving preventive antibiotics like we were treating an entire iceberg, when we only needed to treat the very tip of that iceberg," lead author Dr. Daniel DeSimone, an internal medicine resident at the Mayo Clinic in Rochester, Minn., said in an American Heart Association news release. "Millions of people once getting antibiotics now are not."

DeSimone added, "These findings are reassuring, but additional studies are needed to further support our findings."

Because Olmsted residents are primarily white, the findings might not apply to other races, the researchers said.

SOURCE: American Heart Association, news release, June 11, 2012

The Top 12 Cannabis-Smoking Countries In The World

Yesterday we put together maps of illegal drug use from the U.N.'s World Drug Report 2012, and now we are going through the data to get a better idea of which countries use which drugs most.
Here is a "Top 12" list of countries with the highest annual prevalence of marijuana use (as a percentage of the population aged 15 to 64):
1) Palau: 24.2%
2) Northern Mariana Islands: 22.2%
3) Guam: 18.4%
4) Italy; New Zealand*: 14.6%
6) Nigeria: 14.3%
7) USA: 14.1%
8) Canada: 12.7%
9) Saint Kitts and Nevis: 11.7%
10) Bermuda: 10.9%
11) Spain: 10.6%
12) Australia**: 10.3%
*aged 16 to 64
** aged 14 +

Sunday, 10 June 2012

How Cancers Spread At Cellular Level - Scientists Find Clues

Weill Cornell Medical researchers from the Memorial Sloan-Kettering Cancer Center and their collaborators may have discovered an explanation that could provide a new insight into the 'soil and seed' theory. In an article recently published online in Nature Medicine, they have described a new mechanism to control the metastasis of cancer that could potentially be used as a novel diagnostic tool and treatment option.

Exosome vesicles are a specific subtype of membrane vesicles that circulate in the blood and contain numerous proteins, lipids, and even nucleic acids. In their study, the researchers managed to demonstrate a mechanism by which melanoma cancer cells release small exosome vesicles that travels to various locations, such as the brain, bone, liver and lungs, where the cellular material inside the vesicles fuses with these organs, establishing the perfect environment to spread tumor cells.

The researchers point out that these harmful cancer exosomes can cause various effects; For instance, they are able to trigger inflammation, further the process of leaky blood vessels and 'program' bone marrow progenitor cells to get involved in a soon-occurring metastatic cascade. Exosomes could potentially be advantageous in the diagnoses, prognosis and treatment of cancer, given that they are readily accessible and measurable as they circulate in the bloodstream.

Dr. David C. Lyden, the Stavros S. Niarchos Associate Professor in Pediatric Cardiology and associate professor of Pediatrics and Cell and Developmental Biology at Weill Cornell Medical College, who is also a pediatric neuro-oncologist at Memorial Sloan-Kettering Cancer Center explained: "The exosome profile could be useful in a number of ways - to help detect cancer early, to predict the aggressiveness of a patient's tumor and response to chemotherapy or other treatments, and to understand the risk of cancer recurrence or spread before traditional methods would be able to."

Dr. Jacqueline F. Bromberg, who studies breast cancer, and who is an associate attending physician at Memorial Sloan-Kettering Cancer Center and associate professor of Medicine at Weill Cornell, adds: "We believe each tumor type will have its own exosomal protein profile that will represent each tumor subtype. The exosomal proteins will be useful for prognosis in predicting which patients, including those who develop disease decades after their original diagnosis, will likely be at risk for future metastatic disease."

According to leading author, Dr. Hector Peinado, an instructor of molecular biology at Weill Cornell Medical College's Department of Pediatrics, the findings indicate that if a cancer therapy is to be effective, it has to be multi-layered, saying: "If, in the future, we were able to find a way to control the 'education' of bone marrow cells, as well as the release and content of tumor exosomes in cancer patients, we would be able to curtail and reduce the spread of cancer, and improve the patient's quality of life and survival."

Co-senior author, Dr. Lyden and his team were the first to discover that cells derived from bone marrow (BMDCs) were crucial in order to form primed sites in distant organs, called 'pre-metastatic niches' that provide a perfect base for cells that are spread from a primary tumor. For years they have investigated decoding the biochemical processes that produce these niches, trying to understand the signals that induce the BMDCs to carry out their functions in the niche. At first they investigated exosomes, which were originally believed to consist of mere cell debris used to dump used proteins, but were later found to contain RNA as well as nucleic acids that is found in cancer cells.

They decided to investigate whether exosomes released from a melanoma played a particular role in cancer, and according to Dr. Lyden they discovered:

"Upon their release from the primary tumor, exosomes derived from melanoma cells fuse with cells in distant metastatic organs and lymph nodes, mediating vascular leakiness and inflammation, thereby promoting the formation of pre-metastatic niches that enhance future metastatic growth."

Dr. Peinado explains that the exosomes transfer numerous exosomal proteins to BMDCs, where they are able to reprogram the cells to get involved in the metastatic cascade, saying "We found an oncogenic protein, called MET, that is produced by highly metastatic tumors and packaged into pro-metastatic exosomes. The tumor exosomes circulate, fuse and transfer their information, including the MET oncoprotein, to many cells, such as bone marrow cells, which in turn promote a pro-metastatic phenotype."

In addition, they also discovered that the reprogramming of the BMDCs by exosomes has a long-term effect. This could potentially explain why tumors can lie dormant for years before they suddenly develop into metastatic disease. According to Dr. Bromberg, these findings are vital given that "educated bone marrow is the key in disease recurrence and may even foster a future secondary cancer."

The researchers discovered after examining human blood samples, that patients with stage IV melanoma with widespread metastases had a specific signature of exosomal proteins (including MET), which was not discovered in the blood of patients with non-metastatic melanoma.

According to the researchers, this protein signature could serve as a potential marker to predict which patients with stage III disease and local lymph node metastasis would subsequently be at risk for developing distant metastatic disease.

Dr. Lyden states: "Treatment modalities could be initiated earlier in these high-risk patients to prevent disease progression. Our results demonstrated that MET oncoprotein expression, which can be easily analyzed in a simple blood test, could be used as a new marker of metastatic disease in melanoma patients."

After investigating further, the team found that they could reduce exosomal-induced metastasis either by targeting Rab27a, the protein responsible for production of exosomes or by proactively using exosomes derived from melanoma cells that rarely metastasize in order to reprogram the BMDCs.

Dr. Lyden concludes:

"We have found that less or non-metastatic exosomal proteins may educate bone marrow cells to avoid partaking in the metastatic process. We are working on determining which particular exosomal proteins may be responsible for preventing metastatic participation. This concept may one day be applied to the clinic, where non-metastatic exosome proteins may help prevent the acceleration of tumor growth and metastatic disease, allowing patients with cancer to live longer lives."

Scientists Discover A Stem Cell That Causes Heart Disease

UC Berkeley scientists published a report this week in the journal Nature Communications saying that they have isolated a type of stem cell that causes heart disease in later life.

The research is profound because it contradicts much of the generally accepted theories of what causes arterial hardening, and the concept may also relate to many other diseases could the associated stem cells be pinpointed.

What senior author Song Li, a bioengineering professor at UC Berkeley and a researcher at the Berkeley Stem Cell Center, and his team have uncovered is a dormant stem cell in blood vessel walls, that seems to sit inactive for most of a person's lifetime, before coming to life and causing less functional cells to begin to grow. Li says these new types of cells that start growing in later life, are the root cause of arterial hardening and clogging that are associated with deadly strokes and heart attacks.

Originally, it was thought that the smooth muscle cells in the arteries lining become scarred over time, and this leads to the narrow and brittle arteries that play a major part in causing cardiovascular disease. Not so says Liu: Essentially, what the scientists are saying is that the smooth muscle cells are not to blame. Rather a different kind of stem cell, that Li calls multipotent vascular stem cells, kicks in, and begins growing cells that look much like the smooth muscle cells, but don't function correctly. The cells were not found previously, because there are so few of them, that they were hard to isolate.

Li continues:

"We call them sleeping beauty or sleeping evil cells, because they don't do anything when they're dormant. The stem cells stay quiescent for decades before they start to grow and they make the blood vessels harden."

It almost sounds like something from Blade Runner, where the replicant humans have been deliberately designed to deteriorate and die at a much faster rate than the natural ones. What purpose would it serve the body under standard evolutionary terms to have cells activating later in life that effectively lead to its demise? With the arteries poorly formed, with wrong cell types, the blood flow becomes slowed and can then stopped completely. This causes strokes or heart attacks, depending on the location of the blockage. Strokes and heart attacks are one of the leading causes of death in the United States.

Creating drugs or other genetic treatments to shut down these stem cells or even deactivate them while a person is still young has the potential in the future to prevent arteriole hardening, reverse the damage already done, and even make this type of cardiovascular disease a thing of the past. Perhaps the futuristic Woody Allen movie "Sleeper" where people smoke tobacco and eat a high fat diet because it's healthier is not so far fetched after all.

Li backs up his theory by pointing out that the current ideas, of smooth muscle cells in the artery walls, "dedifferentiating", or basically reverting back to an earlier stage of development and causing the scaring and degeneration seen in hardened arteries, actually had no fundamental proven mechanism to back it.

Li traced the lineage of the cells back to the multipotent vascular stem cells, which are able to form several types of cell, including the smooth muscle cells.

Dr. Deepak Srivastava, director of the Gladstone Institute of Cardiovascular Disease at UCSF, who provided mouse tissue samples to the UC Berkeley scientists but was not involved in the research commented on the dramatic findings:

These findings shift the paradigm ... If the new data holds up, the target for treating vascular disease may be very different than what we've been aiming at ... Maybe the reason we've met with limited success in treating heart disease is because we've been going after the wrong target."

It is worth noting, of course, that the research is ground breaking and will need to be repeated and confirmed by other research teams, and Li did most of his work on mouse rather than human tissue. Nonetheless, it is an impressive work and one that will soon give drug companies a target to begin preventing growth of these negative "death" cells.

Interestingly, the stem cells that form arteries are also capable of becoming nerve, cartilage, bone and fat cells, suggesting why arteries become brittle or even filled with fat deposits. Li says that trying to attack the problem with diets and lower cholesterol is just attacking the symptoms, much like trying to stop a runny nose when you have a cold.

The research is certainly eye opening, and when we think back 100 years to some of the more outlandish scientific theories that have long since been discarded, it doesn't require much stretch of the imagination to realize that there must still be theories taken to be practically a fact, that are at best misleading or at worse plain wrong. In the spirit of a true scientist, Li has reminded us that we have so much more to understand about our existence.

Tuesday, 5 June 2012

Zinc: Supplements for Babies Being Treated With Antibiotics Appear to Save Lives

Giving zinc to newborns being treated with antibiotics for serious infections appears to save lives, according to a new study done in India.
The study, published online in The Lancet last week, compared more than 700 infants under 4 months old who had pneumonia, meningitis or sepsis; half got zinc and half got placebo. The zinc group had 40 percent less “treatment failure,” by which the authors meant anything from death to a decision to switch antibiotics because standard ones were not working. Seventeen children in the placebo group died; only 10 who got zinc did.
The study is “a major finding” but should be replicated before global policy is changed, said Dr. Robert E. Black, an expert in zinc supplementation at the Johns Hopkins Bloomberg School of Public Health who was not involved in the study.
Why zinc seems to help cure infections, diarrhea and pneumonia in zinc-deficient children is unknown, Dr. Black said. Zinc may work very differently when given briefly to dangerously ill children rather than as a supplement given regularly to healthy ones.
Vegetarian diets, like those of Hindus, are often zinc-deficient, Dr. Black said, but so are those of many malnourished children. Breast milk — even from zinc-deficient mothers — contains zinc, though it depletes the mother’s reserves. But when rice or wheat gruel is added to a baby’s diet, he said, phytates in the grain may block zinc absorption.

A Warning to Teenagers Before They Start Dating

After studies emerged more than a decade ago showing that the highest rates of physical and sexual assault happen to women ages 16 to 24, programs to prevent abusive relationships have concentrated on high school and college students.
Some initiatives have shown promise, but overall statistics remain largely unchanged: the most recent government report stated that nearly one in 10 high school students said they had been physically hurt by a boyfriend or girlfriend.
Now a diverse group that includes the Centers for Disease Control and Prevention, the Robert Wood Johnson Foundation and federal lawmakers is trying to forestall dating violence by addressing even younger students: middle schoolers. The goal is to educate them about relationships before they start dating in earnest, even though research shows that some seventh graders have already experienced physical and emotional harm while dating.
That is why, on a recent balmy evening here, 30 teams of teenage artists were kneeling over blackboards in the sculpture garden at the Boise Art Museum, sketching chalk interpretations of poems about relationships written by fellow students.
More than 400 teenagers and parents crowded into this first “ChalkHeart” competition. A bakery provided iced sugar cookies that read “Equality” and “Respect.” A collection of poetry from local students, titled “Love What’s Real” and culled from thousands of submissions, was distributed.
Jadn Soper, 14, brushed aside her electric pink hair as she drew, remarking that most eighth graders know couples who are in demeaning relationships.
“You can tell the way a girl’s mood changes when she’s with that person,” she said. “The boy was funny and charming until he reels you in, and then he’s demanding and has to have it his way.”
Jadn’s classmates from Lowell Scott Middle School nodded. “Middle school has gotten a lot more grown-up than you’d expect,” she added.
Kelly Miller, a former domestic violence prosecutor who runs Start Strong Idaho, the sponsor of the competition, agreed. “Most young people have a sense of what’s abusive,” she said, “but they don’t know what a healthy relationship means.”
The Boise area is one of 11 sites nationwide that each received a $1 million Start Strong grant for middle-school programs, mostly from the Robert Wood Johnson Foundation.
Esta Soler, president of Futures Without Violence, a national anti-violence organization, said there were many reasons to start talking to younger students about abuse.
In middle school, Ms. Soler said, they are rocketing through emotional and social development, beginning to make their own choices. “But they still respond to input from caring adults,” she added. A 2010 study of 1,430 seventh graders in eight middle schools in three cities underscores the need for such education.
The study, commissioned by the Robert Wood Johnson Foundation and released this spring, showed that three-quarters of students had already had a boyfriend or girlfriend. One in three said they had been victims of psychological dating violence; nearly one in six said they had experienced physical dating violence. Almost half said they had been touched in an unwanted sexual way or had been the target of sexual slurs.
It can be daunting to engage adolescents about intimate topics. To ease their awkwardness, Ms. Miller incorporates the students’ creative work and pop icons. For example, her staff created surveys rating the relationships of the characters in “The Hunger Games” books and movie. They sponsor poetry slams, with teenagers reading “Love What’s Real” poems, dancing to a “Relationship Remix” of hits.
Middle-school intervention programs are so new that assessing their effectiveness is difficult. The Centers for Disease Control and Prevention gave grants to middle-school programs in four urban sites last fall. In reauthorization drafts this spring for the Violence Against Women Act — Michael D. Crapo, Republican of Idaho, was a co-author in the Senate — the eligibility age for dating violence education and service programs is now as young as 11.
To sustain elements of the Start Strong program after grants end this fall, staff members have trained health teachers in curriculums that reinforce social and emotional well-being.
At Riverglen Junior High School, Patti Bellan, trained in Canada’s “Fourth R” program about relationships, teaches eighth-grade health at 8:45 a.m. Slight, with a low-key, piquant authority, Mrs. Bellan has clothed the class skeleton in a ChalkHeart T-shirt. She teaches body-language cues, strategies for risky settings and, on this day, responsible decision making. 
She read from PowerPoint slides: a girl who has met an older boy online finally has the chance to see him, at his house, alone. What might happen if she does?
Another: a boy with a longtime girlfriend goes to a party out of town, where another girl flirts with him and invites him over. Consequences?
Students partnered to rank potential impacts — physical, emotional, legal, financial and family. They debated possible aftermaths. “My father would have an aneurysm!” shouted one girl. “My father would kill me!” shouted another. They spoke bluntly about rape, sexually transmitted diseases, pregnancy, prosecution.
Then, Mrs. Bellan asked how long they took to rank the impacts. A minute, they estimated.
“A lot of people believe teenagers can’t make good decisions,” Mrs. Bellan said. “ I disagree. You have just shown that when you pause and think, you have the capability of seeing something through from all angles.”
Start Strong Idaho, a program of the Idaho Coalition Against Sexual and Domestic Violence, works with experts in health and youth programming. It also enlists students who have overcome abusive relationships — an umbrella term for emotional, physical or sexual violence.
They include Laura Hampikian and Sara Hope Leonard. Each girl longed to escape family turmoil by creating what she imagined would be a stable romance.
Ms. Hampikian is now 20 and a confident college sophomore. But in the eighth grade she turned her life over to the bottomless neediness of her boyfriend, who threatened suicide if she left him, began cutting himself, and told her about his family’s violence. She did not realize she was slipping into a fog, detaching from her friends. Pleading with him on the phone nightly until 3 a.m., she believed it was her responsibility to keep him alive.
Ms. Leonard, 17, is a vibrant high school senior. But a few years ago, when her family was living in California, she did anything to please her bristling, possessive, ninth-grade boyfriend.
When her family moved to Boise, Ms. Leonard was so desperate to hold onto her boyfriend that she had them split a set of handcuffs and each wear half, symbolizing their attachment. She obeyed his rules: no giving out her number to boys; no group dates. She completely isolated herself in her new city.
It took both girls a year to extricate themselves from the relationships. When Ms. Leonard graduates from college, she plans to counsel sex-trafficking victims. Ms. Hampikian has been speaking out about healthy teenage relationships as a contestant in the Miss Idaho pageant.
During their crises, neither felt she could tell her parents. That is why, in part, Ms. Miller includes parents in some Start Strong programs.
“Parents themselves underestimate their power to reach young teens,” she said.
One recent night at Riverglen Junior High, parents and sixth graders attended separate workshops about social dynamics they might encounter in the seventh grade.
Start Strong educators handed out statements about relationship behaviors. The students taped statements under columns labeled “Healthy” or “Unhealthy.” (Down the hall, parents had a similar exercise.)
“Jealous when your friend talks to others.”
“Gets insecure when someone doesn’t text back right away.”
Some statements were placed uncertainly between the columns.
“I couldn’t decide,” one boy admitted.
“Some of these are tough to figure out,” said Melissa Ruth, a counselor. She smiled at him. “We’ll talk about it.”

Study finds drinking coffee can delay onset of Alzheimer's disease

A study of senior citizens in Florida found that drinking coffee could delay the onset of or help prevent Alzheimer's disease.
The study, carried out on adults over the age of 65 in Miami and Tampa, found that those with higher levels of caffeine in their blood avoided the onset of Alzheimer's in the two- to four-year period they were monitored.
Dr. Chuanhai Cao, a neuroscientist at the University of South Florida College of Pharmacy, said, "These intriguing results suggest that older adults with mild memory impairment who drink moderate levels of coffee -- about three cups a day -- will not convert to Alzheimer's disease or at least will experience a substantial delay before converting to Alzheimer's."
Cao added, "The results from this study, along with our earlier studies in Alzheimer's mice, are very consistent in indicating that moderate daily caffeine/coffee intake throughout adulthood should appreciably protect against Alzheimer's disease later in life."
The report, led by University of South Florida and University of Miami researchers, warned that 10 million Americans have some form of the condition.
It also found that moderate caffeine intake appeared to reduce the risk of other diseases associated with aging -- including Parkinson's disease, stroke, type 2 diabetes and breast cancer.
The study will be published Tuesday in the Journal of Alzheimer's Disease.

Monday, 4 June 2012

2 people dead after swarms of venomous spiders invade Indian town

A town in India has suddenly been overrun by swarms of venomous spiders, leaving two people dead after being bitten.
It may sound like a B-grade horror movie, but residents of the town of Sadiya, in Assam state, say that on the evening of May 8 as they were celebrating a Hindu festival swarms of spiders suddenly appeared and attacked them, The Times of India reported.
Over the next few days two people -- a man, Purnakanta Buragohain, and an unnamed school boy -- died after being bitten by the spiders. Scores more turned up at the town's hospital with spider bites.
'Some of the victims claimed the spider latched on to them after biting.'
- Dr. L.R. Saikia, head of the department of life sciences at Dibrugarh University
Local resident Jintu Gogoi spent a day in the hospital complaining of excruciating pain and nausea after being bitten. He said weeks later his finger was still blackened and swollen.
District authorities are also panicking -- and they are considering spraying the town with the insecticide DDT.
Locals say the most terrifying aspect is that spiders appear in swarms and their behavior is highly aggressive.
"It leaps at anything that comes close. Some of the victims claimed the spider latched on to them after biting. If that is so, it needs to be dealt with carefully. The chelicerae and fangs of this critter are quite powerful," head of the department of life sciences at Dibrugarh University Dr. L.R. Saikia said.
Teams of Indian arachnid experts have flocked to the town, hoping to identify the species, but so far they have drawn a blank.
They say it could be a tarantula, a black wishbone or even a funnel-web spider -- or it could be a whole new species.
One thing they agree on is that it is not native to the area as there is no record of venomous spiders in Assam. The black wishbone and funnel-web are native to Australia.
Researchers are also still running tests to find out the toxicity of the spiders' venom.
Dr. Anil Phatowali, superintendent of the town's hospital, said they had not administered antivenin as they could not be certain the spider was venomous at all.
He also pointed out other factors may have contributed to the two reported fatalities.
"All the bite patients first went to witch doctors, who cut open their wounds with razors, drained out blood and burnt it. That could have also made them sick," Phatowali said.

Giving blood may provide health benefits for obese

Some obese people may improve their health by donating blood, a preliminary study from Germany suggests.
In the study, obese people with metabolic syndrome who had blood drawn experienced a reduction in blood pressure, along with other changes that linked with a reduced risk of heart disease, the researchers said.
Metabolic syndrome is a collection of symptoms associated with heart disease, including high blood sugar, high blood pressureand low levels of "good" cholesterol. The syndrome has been linked with increased risks of stroke, coronary artery disease and Type 2 diabetes. The main treatment is weight loss.
The findings suggest doctors might consider blood donation as a possible treatment for people with metabolic syndrome who have above-normal iron levels (a common situation), said study researcher Andreas Michalsen, of the Charité-University Medical Centre in Berlin.
However larger trials are needed to confirm the results and evaluate the long-term risks of such a treatment, Michalsen said.
Dr. Pieter Cohen, an assistant professor of medicine at Harvard Medical School and a general internist at Cambridge Health Alliance, said blood donation should not be recommended as a treatment for metabolic syndrome unless more studies are done.
"You want to know [that] it would make them live longer," or reduce the actual risk of heart attack and stroke, not just markers linked with those conditions, Cohen said.
Blood pressure drop
Previous studies have shown high iron levels are associated with metabolic syndrome and Type 2 diabetes, the researchers said. And one small study found that bloodletting reduced blood pressure in patients with treatment-resistant high blood pressure. However, the effects of blood withdrawal on people with metabolic syndrome have not been rigorously examined.
Michalsen and colleagues randomly assigned 64 obese people with metabolic syndrome to have their blood drawn, or to receive no specific treatment. At the beginning of the study, those in the bloodletting group had 10 ounces (300 milliliters) of blood removed, and four weeks later, had another 8.5 to 17 ounces (250 to 500 ml) removed.
After six weeks, patients in the bloodletting group saw their systolic blood pressure drop by an average of 18 mmHg, from 148.5 mmHg to 130.5 mmHg. Systolic blood pressure (the "top" blood pressure number) is considered to be high if it is above 140 mmHg, and moderately high if it is between 120 and 140 mmHg.
In the nontreatment group, blood pressure was reduced, on average, from 144.7 mmHg to 143.8 mmHg.
Previous studies have found that a reduction in systolic blood pressure by 10 mmHg can lead to a 22 percent reduction in therisk of heart attack, heart failure and coronary artery disease, and a 41 percent reduction in stroke risk, the researchers said.
The new study also found bloodletting resulted in a significant decrease in heart rate and blood glucose levels, the researchers said.
Blood donation as a therapy?
Reducing the volume of blood through bloodletting would be expected to result in a decrease in blood pressure, Cohen said, but it's not clear if this approach could stabilize blood pressure in these patients,  and the long-term effects need to be studied.
The study researchers did not report whether study participants were taking medications that reduce blood pressure, Cohen said. If patients' blood pressure was not being treated properly to begin with, then the bloodletting may have had a greater effect on this group than it would on others, Cohen said.
The researchers also did not take into account any changes in lifestyle and eating habits that occurred during the study, which may have affected blood pressure.
"There's good stuff in our blood too, that we need to fight infections," Cohen said. "We can't assume that if you take out some bad stuff in a pint of blood, that you're not also taking out some good stuff."
Because metabolic syndrome is not contagious, blood donated from those with the condition would not pose health risks to those receiving it, Michalsen said.
Blood withdrawal is already used a treatment for some conditions, such as hemochromatosis, a condition that occurs when too much iron builds up in the body.

More advanced therapies are being aimed at cancer

New research shows a sharp escalation in the weapons race against cancer, with several high-tech approaches long dreamed of but not possible or successful until now.
At a weekend conference of more than 30,000 cancer specialists, scientists reported:
-New "smart" drugs that deliver powerful poisons directly to cancer cells while leaving healthy ones alone.
-A new tool that helps the immune system attack a broad range of cancer types.
-Treatments aimed at new genes and cancer pathways, plus better tests to predict which patients will benefit from them.
"I see major advances being made in big diseases" such as breast and prostate cancers, said Dr. Richard Pazdur, cancer drug chief at the federal Food and Drug Administration, which on Wednesday announced a new policy intended to speed breast cancer drugs to the market.
The field continues to move toward more precise treatments with fewer side effects and away from old-style chemotherapy that was "like dropping a bomb on the body," he said.
In fact, an emerging class of "smart bombs" was one of the most hopeful developments reported at the meeting of the American Society of Clinical Oncology.
These are two-punch weapons that combine substances called antibodies, which bond with specific cancer cells, and toxins that are too potent to be given by themselves. A chemical link holds them together until they attach to a tumor cell, releasing the poison inside it and killing the cell.
"This is a classic example of the magic bullet concept" first proposed more than 100 years ago but only now possible with advances in technology, said Dr. Louis Weiner, director of Georgetown Lombardi Comprehensive Cancer Center.
"The antibody basically targets this very toxic drug right to the cancer cell and places it inside the cancer cell where the drug can do its damage" without harming healthy cells nearby, he said.
On Sunday, a large study showed that one such drug - Genentech's T-DM1 - delayed the time until cancer got worse in women with very advanced breast cancer. The drug also seems to be improving survival, although it will take more time to know for sure. So far, women on the new treatment were living more than a year longer than a comparison group of women who were given two other drugs.
Dozens of similar "smart bomb" drugs are in development. On Monday, Pfizer Inc. plans to report on one it is testing for certain types of lymphoma and leukemia. Only one such drug is on the market now - Adcetris, sold by Seattle Genetics Inc. for some less common types of lymphoma.
The other big news at the conference involved a very different approach: using the immune system to fight cancer. For more than a century, doctors have been trying to harness its power, but tumor cells have cloaking mechanisms that have kept the immune system from recognizing them as "enemy" and going on the attack.
Bristol-Myers Squibb Co. has developed two drugs - one aimed at cancer cells and the other at key soldier cells of the immune system - to remove one of these invisibility cloaks. Two studies involving nearly 500 people found some tumor shrinkage in up to one quarter of patients with lung and kidney cancers as well as the deadly skin cancer, melanoma. The treatments had less impact against colon and prostate cancer.
These are only early results - not survival comparisons or definitive tests, doctors warn. More testing is needed to even establish safety. In one study, three patients died of a lung inflammation considered due to the treatment.
However, ordinary chemotherapy can prove fatal, too, said one study leader, Dr. Julie Brahmer of Johns Hopkins University.
"There were a few patients who had a complete remission" from the immune system treatments and most patients suffered few side effects, she said. "It's great to see patients feeling well. They don't have hair loss, they don't have a drop in blood counts and are not as prone to infections."
Dr. Roy Herbst, medical oncology chief at Yale Cancer Center in New Haven, Conn., was hopeful.
"I haven't seen anything this good" for many years for treating lung cancer, he said. "I'd be very surprised if there wasn't some benefit" on survival, said Herbst, who has consulted for the drug's maker.
Other doctors, including Pfizer's cancer drug development chief, Dr. Mace Rothenberg, noted progress on new diagnostic tests to predict which drugs will work for which patients. Cost, time and difficulty have kept many of them from being practical in everyday settings for cancer patients, but "a lot of these barriers are falling," Rothenberg said.
"Every time we say `this technology is 5 to 10 years off, we've been wrong" and progress has come sooner, he said.

Friday, 1 June 2012

Seeds Inherit Memories of Enemies

After plants acquire resistance to pests and pathogens, their offspring shoot up through the soil with better defenses.  The findings, published in a recent series of papers in Plant Physiology, are the first to identify small interfering RNAs (siRNAs) as a possible mechanism of this inherited memory response, and suggest a new strategy for managing crop pests.
“It’s sort of like giving a vaccine to the parent and seeing immunity in the child,” said Andrei Alyokhin, who studies insect-plant interactions at the University of Maine and was not involved in the research. “It could help with the pest problem—induced resistance in plants is an extremely underutilized approach.”
Plants eventually come to know their enemies.  When a caterpillar first bites into a juicy leaf, plant cells release toxic chemicals that make the pest grow more slowly. This initial encounter with a hungry herbivore primes the plant—when caterpillars come back for a second invasion, the defense reaction is more aggressive.
This is why George Jander of the Boyce Thompson Institute for Plant Research in Ithaca, New York, and his colleagues intentionally expose their tomato plants to caterpillars. “The priming increases resistance, and we are now seeing inheritance in the next generation,” he said.
Jander and his colleagues placed a corn earworm on each of nearly one hundred tomato seedlings.  The researchers similarly exposed Arabidopsis weeds to white cabbage butterfly larvae.  They then planted a second generation of plants in a pest-free environment, and introduced the insects after several weeks. Sure enough, offspring of plants exposed to the pests sustained less leaf damaged, and the caterpillars grew to only 30 to 50 percent the size of the insects that plagued parent plants.  In Arabidopsis, this priming was even passed on to a third generation: the grandchildren of infested plants showed heightened resistance, even when their parents had not been exposed.
And the approach may be applicable to a wide range of pest species.  For example, after infesting parent plants with the diamond back moth, Jander found the white cabbage butterfly and beet armyworm were smaller and less abundant on progeny plants. Strangely, however, the diamond back moth devoured leaves as usual, raising the question of just how specific these defense responses are.
“I suspect there is specificity—it may be that plants distinguish between herbivores—but we don’t really know how these interactions work,” said Sergio Rasmann, a biologist at the University of Lausanne in Switzerland who collaborates with Jander. It could also be that the plants “turn on the same defense irrespective of what’s feeding on them,” said Jander.
Taking a closer look at the mechanisms of inheritance, Rasmann first turned to small interfering RNAs (siRNAs)—a class of molecules so small they can potentially diffuse through the plant from the leaves to a developing seed. When he grew mutants that lacked siRNAs, the second generation plants showed no sign of an inherited defense response.  “It seems you can’t prime the seeds without the siRNAs,” said Rasmann.
The findings are the first to demonstrate a role for siRNAs in next generation priming, wrote Ian Baldwin, of the Max Planck Institute in Jena, Germany, who was not involved in the research, in an email to The Scientist. But exactly how they work is unclear. “The actual siRNAs that are transmitted to the seeds, and their targets, still need to be identified.”
Jander questions whether the siRNAs serve as the vehicle of inheritance.  “[They could] also move to the seed and catalyze DNA methylation,” he said.  Indeed, after infesting Arabidopsis plants with virulent Pseudomonas syringae bacteria, researchers at the University of Sheffield found evidence for the combined regulation of methylation and histone modification.
The findings suggest a new way that farmers might protect future generations of crops—collect seeds from infested plants to grow stronger plants the following year.  “Farmers probably won’t want to rely on this alone, but when [next-generation priming] is incorporated into organic farming as one of many methods, it can help,” said Jander.
Seed farms might even employ benign bacteria, according to results published by Brigitte Mauch-Mani at the University of Neushâtel in Switzerland.  When the team exposed plants to a transformed strain of Pseudomonas syringae that triggered defenses but not disease, offspring were still more resistant to the virulent bacteria.
Although for industrial-scale applications, it might be easiest to use low-toxic chemicals to trigger the molecular defenses instigated by bacteria and herbivores, Jander said. He recently sprayed plants never exposed to caterpillars with the hormone methyl jasmonate, and found offspring were more resistant to disease than control groups. If chemical technology can be perfected, it might help researchers amplify the inherited defense response.
“The idea is very new, and there is a lot of work to be done,” Rasmann said.  “But if we can harness the next generation response, it might reduce the overwhelming loads of pesticides applied crop fields now days.”

Active Brains Help Heal Paralysis

Brain engagement and nerve stimulation work together to help paralyzed rats regain the ability to walk: Engaging the rats in specific tasks, such as obtaining a treat, while stimulating the spinal cord and forcing the animals to mimic walking movements a Swiss-led team of international scientists was able to restore voluntary movement. The results, published today (May 31) in Science, gives insight into how the nervous system reorganizes to compensate for severe spinal injuries and points to future strategies for treating patients with paralyzed limbs.
“The crux of the study is that if you do [rehab] right, you can restore voluntary control through new [nerve] circuits,” explained Michael Beattie, a neuroscientist at the Brain and Spinal Injury Center at the University of California, San Francisco, who was not involved with the research.
The combination of training and nerve stimulation has already been shown to restore function after paralysis, said V. Reggie Edgerton, a physiologist at the University of California, Los Angeles. For example, his own work with a human patient demonstrated that such brain engagement and nerve stimulation synergized to enable the patient to regain some control over leg movement after a paralyzing injury.
To examine how training and nerve stimulation might combine to help paralyzed patients regain motor function, Grégroire Courtine at the University of Zurich and the Swiss Federal Institute of Technology and his colleagues designed a spinal cord injury model in rats. Spinal cord injuries in humans that induce total paralysis do not always result from complete severing of the spinal cord, so Courtine and his colleagues carefully cut halfway across rats’ spinal cords about midway down their backs, and then cut across the other half a bit lower down. Although no single nerve ran intact up the spine, the damage was not total, explained Courtine.
Next came a specially designed support jacket, which the researchers believe help the rats feel safe enough to walk, but didn’t force movement, said Courtine. Without stimulation, the spinal nerves below the injuries were dormant, but a combination of neurotransmitters and electrical impulses helped raise their excitability to the point that proper sensory input could produce involuntary stepping motions. That sensory input came when the researchers placed the rats on treadmills. But this was not enough—even after weeks of “training” on the treadmill, the involuntary motions could not help the rats regain control of their limbs.
The trick was making the brain “want to step,” Edgerton explained. The researchers achieved this by providing the animals with a reward (treats, for instance) that they had to walk to reach. With this encouragement, the rats slowly regained the ability to initiate walking, but only when receiving the electrochemical stimulation that boosted the excitability of the neurons below the injury. “After about 5 to 8 weeks, they could sprint with their entire body weight,” noted Courtine, or avoid obstacles—but again, only with the nerve stimulation.
“The mechanism [underlying rehabilitation] was surprising,” Courtine said. Closer investigations of the injuries showed extensive reorganization of the neurons projecting from the rats’ motor cortex down the spine. But rather than growing to reach their initial end points, the neurons appeared to be reorganizing, forming new connections and circuits around the site of injury.
Courtine and his colleagues found that rats trained with voluntary activities had increased nerve fiber density and that these fibers appeared to be making synapses with relay neurons in the spine, which help connect signals between the muscles and brain but don’t extend all the way to the motor cortex. In the brain stem, these mice also exhibited increases in fiber density, as well as greater innervation of fibers important in initiating and sustaining movement. The results show how “the motor cortex will reorganize and … use the residual capacity of the spinal cord,” Beattie said.
Activating both the descending pathways (engaging the rats’ brains) and ascending pathways (through nerve stimulation and treadmill locomotion) was critical for the technique’s success, said Edgerton, who has collaborated with Courtine in the past, but did not participate in the current study. But still, the rodents were never able to initiate movement in the absence of the electrical and chemical stimulation of the nerves below the injury. The next steps, he said, will be gleaning more detailed information about how and where to stimulate the spinal cord, which in turn could help extend such strategies to human patients.
Similar spinal cord “training” technology exists for humans, but the new study suggests that it’s not enough. “They need to engage their brains,” Edgerton said. “Without voluntary effort, nothing is likely to happen.” In addition to adding brain stimulation, Beattie envisions a strategy whereby nerve stem cell transplants could bridge areas of tissue injury, encouraging growth and forging new connections.  Combining such efforts may one day help paralyzed patients with even more severe spinal injuries regain movement.
“It’s really fascinating,” said Courtine, “the tremendous potential plasticity [of the spinal cord] even after such a serious lesion.”

2012 Kavli Prize Winners

Kavli Foundation announced this year’s winners today (May 31), which include seven scientists in astrophysics, nanoscience, and neuroscience.
In nanoscience, Mildred S. Dresselhaus of the Massachusetts Institute of Technology was “recognized for her pioneering contributions to the study of phonons, electron-phonon interactions, and thermal transport in nanostructures,” According to the Foundation’s announcement. Dresselhaus has led research investigating bismuth nanowires and carbon nanotubes.
The 2012 laureates in neuroscience, “recognized for elucidating basic neuronal mechanisms underlying perception and decision,” are Cornelia Isabella Bargmann of Rockefeller University, who investigates sensory responses in C. elegans; Winfried Denk of Max Planck Institute for Medical Research in Germany, who images brain circuits; and Ann M. Graybiel at MIT, whose research elucidates brain states that contribute to the dysregulation of behavior patterns.
The astrophysics prize was awarded for “discovering and characterizing the Kuiper Belt and its largest members, work that led to a major advance in the understanding of the history of our planetary system,” the Foundation stated. David C. Jewitt at the University of California, Los Angeles, who looks to comets for clues about planet formation; Jane Luu at MIT’s Lincoln Laboratory, who spotted the first Kuiper belt object with Jewitt in 1992; and Michael E. Brown at the  California Institute of Technology, whose work contributed to the down-grading of Pluto to dwarf-planet status.