Horizontal levitation: The ultimate solution to particle separation

 

June 18, 2014

Springer Science+Business Media

Separating particles from the liquid they are in can now be done with a new concept. Magnetic separators exploit the difference in magnetic properties between minerals, for example when separating magnetite from quartz. But this exercise becomes considerably more complex when the particles are not magnetic. In the wake of previous particle levitation experiments under high-power magnetic fields, a new study reveals that particles are deflected away from the magnet's round-shaped bore center in a horizontal direction.

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Magnetic separators exploit the difference in magnetic properties between minerals, for example when separating magnetite from quartz. But this exercise becomes considerably more complex when the particles are not magnetic. In the wake of previous particle levitation experiments under high-power magnetic fields, a new study reveals that particles are deflected away from the magnet's round-shaped bore centre in a horizontal direction. Previous studies had observed the vertical levitation of the particles. These findings are presented by Shixiao Liu from the Faculty of Engineering, University of Nottingham, UK and colleagues, in a paper recently published in EPJ E, and could led to a new concept in particles and minerals separation technologies.

The authors analysed video frames covering 0.1 second each of the movement of glass and pyrite particles of roughly one millimetre diameter in a solution that was subjected to a strong non-uniform magnetic field created by a superconducting magnet. The authors show that pyrite and glass particles were deflected and settled at certain positions in a specially designed container. They explain that this pattern is due to differences in the particles' densities and magnetic susceptibilities.

The gradient in the magnetic field gives rise to a radial force-defined by the particles' magnetic properties-capable of separating the glass from pyrite particles. At the same time, the magnetic field gradient also induces the so-called Magneto-Archimedes force, which compensates for the force of gravity. Surprisingly, the particle size seems to have little influence on the results, at least for the limited size range examined in these experiments.

The authors then confirmed their experimental findings using mathematical simulations of the particle displacement.

World Cup hotels: Where teams are staying in Brazil

 

 

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All eyes are on Brazil this summer as the world's soccer teams descend on the South American country for the 2014 World Cup. Wonder where all those players are staying? Trivago.ca takes Sun Media inside 10 of the hotels the world's top soccer teams are staying at. From beachfront resorts to mountain retreats, check out these 10 gorgeous properties in our gallery.

England - Royal Tulip, Rio de Janeiro: The England squad will be making the Royal Tulip their home this summer – a stylish hotel located on the São Conrado beach in Rio de Janeiro. Fully equipped with an outdoor pool and stylish bar, the hotel certainly delivers on leisure activities, with two tennis courts, a gym and a sauna to help unwind after a tough match. (Courtesy Royal Tulip, Rio de Janeiro)

10 Reasons Why Rio de Janeiro is Awesome!

 

Posted in Featured, South America on February 10, 2014

Many times on my travels I have found there are cities that are hyped up to be something extra-ordinary, extra special, something spectacular, only to get there and feel disappointed because it just didn’t live up to the huge promotion it was given. I expected this to happen in Rio de Janeiro. I expected it not to be as good as I had imagined. I arrived in a bad mood thinking it wouldn’t be everything I wanted it to be. I was wrong. It was better than I imagined. I genuinely love this city and for that reason I thought I’d share with you 10 reasons why I think it’s awesome! I hope it makes you want to visit Rio if you haven’t visited already!

 

Breath-taking coastline

Usually I hate busy beaches. As a self confessed introvert on my travels I like my own space, and in particular I like empty or near-empty beaches. It’s only then I feel I can enjoy the sea views and the cusp of a wave to its full extent. However, even on an extremely busy weekend, walking along Rio de Janeiro’s most famous beaches – Copacabana and Ipanema - I couldn’t help but be over-awed by the stunning coastline landscape here. Particularly in the case of Ipanema (see me pictured at Ipanema beach above), despite the huge crowds of people you just couldn’t deny it was an incredible coastal view. You could definitely under stand the popularity and why these beaches are known the world over.

 

Well prepared for tourists

One of the things I was most impressed with in Rio was the strong presence at the International Airport and major tourist sites of tourist information points and people handing out free city maps. Particularly at the airport I think I passed around 3 separate tourist information desks, one of which you passed before you’d even collected your hold luggage. Something simple like this made it so much easier getting from the International Airport into town by bus and it was a small yet reassuring sign that Rio is ready for the World Cup in June despite its recent troubles.

 

Super friendly & sociable locals

I’ve only ever had good experiences when I’ve met Brazilian people on my travels around the world. They just seem to be friendly and sociable by nature and my time in Rio de Janeiro was no different. Every time I asked for help or directions people always seemed happy to help. When I was sitting in cafes on my own local people would just come up and talk to me even though I was a complete stranger. If there wasn’t enough seats in a restaurant people who’d never met each other before would just squeeze up next to one another and chat while they ate. Usually the big cities are the places where people can often be less friendly but I personally did not experience this in Rio de Janeiro. Genuinely, everyone was really nice to me. The place just had a cool vibe and I loved hanging out with the local people here.

 

Christ the Redeemer

It’s probably one of the few landmarks around the world that could rival the Eiffel Tower for fame - and you can see exactly why when you visit the ‘Christ the Redeemer’ statue in Rio de Janeiro. In actual fact, whilst the trip to view the statue up close was a worth while one-time experience in order to see it up close, in my opinion the statue is actually most impressive when viewed from afar around the city. For example, the views of ‘Christ the Redeemer’ from Botafogo – the neighbourhood where I was staying - were particularly impressive. They made what would have been a normal day shopping for example turn into something more inspiring when you see the statue in the distance (and I’m not even religious!)

Açaí is a non-alcoholic berry fruit drink that you drink/eat with a spoon. The Açaí Palm (the plant which the berries come from) is native to Central and South America but is particularly popular in Brazil. I personally had never heard of Açaí until I arrived in Rio and so it was therefore  a very welcome surprise! I actually think I got mildly addicted to the stuff while I was here, and considering how many juice bars there are in Rio, it was a good excuse to stop every so often and have a drink of Açaí when the hot summer weather here got too much.

 

Caipirinha

Rio de Janeiro is a party city. Even if you were like me and chose not to focus your activities here on partying so much, you can’t come to Rio and not taste a local Caiprinha in Brazil’s most famous city! A word of warning though – they do make them strong!

 

Brazilian Samba

Another popular activity to experience while you’re in Rio is to take some Samba lessons. You also may want to go see a Samba show. I personally recommend doing both, but I think you’ll also be hard pressed to find a Samba show in Rio de Janeiro that isn’t also a tourist trap. Not that there’s anything wrong with that as long as it’s fun and you have a good time, but personally I think for a more authentic experience it’s better to go learn a bit of the dance with a local qualified instructor followed by a trip to a samba club. You’ll find many of the hostels in Rio offer lessons in house or can arrange them for you (which is what I did in Rio as I had limited time to shop around), but I also heard good things about ‘Rio Samba Dancer’ school, a local company who offer group lessons to tourists.

 

Lagoa Rodrigo de Freitas

 

For me the Rodrigo de Freitas lake was one of the major visual highlights of Rio de Janeiro. A) Because the lake itself it very tranquil and beautiful, and B) because of the great views of the ‘Christ the Redeemer’ statue from the lake side. It’s the best place in my opinion to view Rio’s iconic statue from afar, but it’s also just a really nice place to visit on its own if you’re chilling out on a sunny day or want to go for a bike ride. You’ll also meet a lot of local people here on weekends out cycling or having lunch with their family.

 

Pão de Açúcar Cable Car

Again, another great spot for epic views of Rio de Janiero! The Pão de Açúcar is a double cliff/mountain top and cable car situated on the coast in between Rio’s Botafogo neighbourhood and Copacabana. There are two cable cars that take you to both cliff tops and allow you some stunning views of the city. There is also more room to move than you’ll find when you go to visit the Christ Redeemer statue, so may allow you some better photos of the city. However, this attraction is also rather pricey at 60 Brazilian Reals for 1 adult - more than what it will cost you for much more famous attractions in the city! Still, the views are incredible.

 

Sunshine Weather

Rio never really gets cold. Certainly not by Northern European standards where I come from. When I was there a few weeks ago most days were around the 30 ºC mark, but on a particularly hot summer day it can reach as high as 40 ºC. In winter the weather here is usually around 20 ºC to 25 ºC (what an average summer would be like for me in Scotland!) Although you can find it dips down to as low as 15 ºC on a ‘cold’ winter day here. Essentially Rio has the perfect climate for a visit any time of year.

- I really loved Rio de Janeiro during my time here. I remember arriving in Rio feeling a little down and in a bit of a bluesy mood only to immediately feel much more cheery and uplifted as soon as I stepped out into the city. It’s just one of those places that has that kind of affect on you. It’s beautiful, sunny, there’s lots to do and the local people are friendly. The only thing I wished for was that I had more time here. It’s certainly on my agenda to make a return visit here at some point in the future. It really is an awesome city!

Yoga exercise program tailored for pulmonary hypertension patients

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A first-of-its-kind yoga exercise program has been developed by Henry Ford Hospital for patients living with pulmonary hypertension, a chronic lung disease that afflicts women at least two times more than men.

Called Yoga for PH, the 40-minute program includes three yoga exercise levels and a nutrition and lifestyle discussion. It is available for free download on iTunes and Googleplay.

The program was developed by Henry Ford pulmonologist Rana Awdish, M.D. , a 20-year yoga practitioner.

"These yoga exercises are modified specifically for the needs of pulmonary hypertension patients and can be done safely regardless of the patient's level of physical fitness," Dr. Awdish says. "We all recognize the importance of exercise. But for these patients, routine activities like walking up stairs can be challenging, so convincing them they can have success exercising can be challenging.”

"What we've created are a series of gentle, low-impact exercises that can be in the comfort of their own home, sitting in a chair or standing. These are designed to improve balance, strength, reduce stress and calm the nervous system. Even patients who require oxygen can perform these exercises."

Henry Ford Hospital is among the largest referral centers for pulmonary hypertension in the United States, and is one of only two hospitals in Michigan that offer pulmonary and critical care medicine fellowship programs. The hospital has an intensive care unit dedicated to the care of pulmonary hypertension patients, with specially-trained nurses who are experts in managing the complex needs of these patients.

Dr. Awdish says the idea for a yoga exercise program was borne from requests from patients. It was funded by a grant from the Pulmonary Hypertension Association.

"The interest was all organic," she says, "and the patients wanted to know how to do yoga safely, despite their condition."

Pulmonary hypertension, or PH, is high blood pressure in the lungs. The blood vessels in the lungs become narrowed and the heart has to work harder to pump blood through them. It typically develops between the ages of 20 and 60, and is two or three times more common in women than men.

Common symptoms are shortness of breath, fatigue, chest pain and a racing heartbeat. As PH worsens, symptoms may limit physical activity.

While PH has no cure, the earlier the disease is treated, the better the outcomes are for patients. Treatment options to relieve symptoms and slow the progression of the disease include medication, surgical procedures and lifestyle changes. "With proper medication," Dr. Awdish says, "patients can live a long and healthy life."

"Any amount of exercise is beneficial is patients," she says. "We know that when patients are engaged in their treatment and their healing, they have better outcomes. These yoga exercises will help aid their healing process."

Hippocampal activity during music listening exposes the memory-boosting power of music

June 18, 2014

Suomen Akatemia (Academy of Finland)

For the first time the hippocampus —- a brain structure crucial for creating long-lasting memories —- has been observed to be active in response to recurring musical phrases while listening to music. Thus, the hippocampal involvement in long-term memory may be less specific than previously thought, indicating that short and long-term memory processes may depend on each other after all.

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Activity in an area (in red) within the hippocampus (in green) increased when musical motifs in the piece were repeated.

For the first time the hippocampus -- a brain structure crucial for creating long-lasting memories -- has been observed to be active in response to recurring musical phrases while listening to music. Thus, the hippocampal involvement in long-term memory may be less specific than previously thought, indicating that short and long-term memory processes may depend on each other after all.

The study was conducted at the University of Jyväskylä and the AMI Center of Aalto University, by a group of researchers led by Academy Professor Petri Toiviainen, the Finnish Centre for Interdisciplinary Music Research (CIMR) at the University of Jyväskylä, and Dr. Elvira Brattico, Aalto University and the University of Helsinki. Results of the study were published in Cortex, a journal devoted to the study of the nervous system and behaviour.

"Our study basically shows an increase of activity in the medial temporal lobe areas -- best known for being essential for long term memory -- when musical motifs in the piece were repeated. This means that the lobe areas are engaged in the short-term recognition of musical phrases," explains Iballa Burunat, the leading author of the study. Dr. Brattico adds: "Importantly, this hadn't been observed before in music neuroscience."

A fundamental highlight of the study is the use of a setting that is more natural than those traditionally employed in neuroscience: the participants' only task was to attentively listen to an Argentinian tango from beginning to end. This kind of music provides well-defined, salient musical motifs that are easy to follow. They can be used to study recognition processes in the brain without having to resort to sound created in a lab. By using this more realistic approach, the researchers were able to identify brain areas involved in motif tracking without having to rely on the participants' ability to self-report, which would have constrained the study of brain processes.

"We think that our novel method allowed us to uncover this phenomenon. In other words, the identified areas may also be related to the formation of a more permanent memory trace of a musical piece, enabled precisely by the very use of a real-life stimulus (the recording of a live performance) in a realistic situation where participants just listen to the music as their brain responses are recorded," Iballa Burunat goes on to explain. Listening to the music from beginning to end may have imprinted the participants with a long lasting memory of the tune. This might not be expected were the participants exposed to a simpler stimulus in controlled conditions, as is the case in most studies in music and memory.

Although a real-life setting may be sufficient to trigger the involvement of the hippocampus, another explanation could lie in music's capacity to elicit emotions. "We cannot ignore music's emotional power which is thought to be crucial for the mnemonic power of music as to how and what we remember. There is evidence on the robust integration of music, memory and emotion -- take for instance autobiographical memories. So it wouldn't be surprising that the emotional content of the music may well have been a factor in triggering these limbic responses," she continues. This makes sense, since the chosen musical piece by Astor Piazzolla was a tribute to his father after his sudden death, and so the main purpose of the piece was to be of a deeply emotional nature."

Certainly, the hippocampus -- as part of the limbic system -- is connected to neural circuitry involved in emotional behavior, and ongoing research suggests that emotional events seem to be more memorable than neutral ones. The authors emphasize that these results should motivate similar approaches to study verbal or visual short term memory by tracking the themes or repetitive structures of a given stimulus. Moreover, the study has implications for neurodegenerative diseases associated with hippocampal atrophy, like Alzheimer's. "Music may positively affect patients if used wisely to stimulate their hippocampi, and thus their memory system," Academy Professor Petri Toiviainen indicates. A better understanding of the link between music and memory could have widespread repercussions, leading to novel interventions to rehabilitate or improve the life quality of patients with neurodegenerative conditions.

The study was supported by the Academy of Finland.

Race a factor in mortality in heart attack patients on anti-clotting drug

 

These variants increased patients' risk of dying in the year following a first heart attack, but they appeared to do so for different reasons depending on race, according to a study at Washington University School of Medicine in St. Louis.

In particular, the team found that two DNA variants common in African Americans were associated with an increased risk of both bleeding and death. In Caucasians, a different variant was linked to additional heart attacks and a higher risk of death.

The research is published June 17 in the American Heart Association journal Circulation: Cardiovascular Genetics.

The variations influence the way people metabolize clopidogrel and can alter its effectiveness. The blood-thinning drug commonly is prescribed after a heart attack to reduce the likelihood of another heart attack or a stroke.

"The research is provocative," said the study's first author, cardiologist Sharon Cresci, MD, assistant professor of medicine and of genetics. "Knowing about potential genetic differences based on race can help physicians tailor drugs to patients based on their genetic makeup."

Clopidogrel is metabolized in the liver, where it is turned into its active form via a group of enzymes called cytochrome P450, or CYP for short. Although clopidogrel is effective in many patients, earlier studies determined that some people metabolize the drug better than others.

Indeed, in 2010, the Food and Drug Administration added a "black box" warning to labels of clopidogrel after research that primarily involved Caucasians showed that people with a particular CYP genetic variant metabolized the drug poorly, which reduced the amount of the drug circulating in the blood. These patients had a higher risk of heart attack and stroke.

Additional studies showed that other CYP gene variants are linked to the rapid metabolism of clopidogrel and that patients with those variants had a higher risk of bleeding.

But it has not been clear until now that the effects of these particular gene variations can vary by race in patients taking clopidogrel after a heart attack.

For the study, the researchers analyzed CYP variants among 2,062 Caucasians and 670 African Americans who suffered heart attacks. Nearly 80 percent of the Caucasians and 65 percent of the African Americans were prescribed clopidogrel. The patients were enrolled in a major study known as TRIUMPH (Translational Research Investigating Underlying disparities in acute Myocardial infarction Patients' Health) conducted from 2005 to 2008 at 24 U.S. hospitals, including Barnes-Jewish Hospital in St. Louis.

Among patients taking clopidogrel, the one-year mortality rate for African Americans was 7.2 percent, compared with 3.6 percent for Caucasians.

Caucasians who carried the CYP2C19*2 variant, which has been linked to poor metabolism of the drug, had a higher rate of repeat heart attacks and death. The higher rate of heart attacks is consistent with the slower metabolism of clopidogrel.

However, among African Americans treated with clopidogrel, the CYP2C19*2 variant was not associated with a higher rate of death.

Rather, African Americans had higher rates of bleeding and death if they carried either of two other variants: CYP1A2*1C or CYP2C19*17, the latter of which has been associated with the rapid metabolism of clopidogrel. Among Caucasians on clopidogrel, neither variant increased the risk of death.

"This is very novel information that begs for more research," said cardiologist Richard G. Bach, MD, the study's senior author and an associate professor of medicine at Washington University.

Although genetic testing is available to identify CYP variants in a patient's DNA, these tests generally are not widely used by cardiologists. Results of the current study suggest this practice may need to be reconsidered.

"This research is an important addition to the field because previous studies looking at CYP gene variants and their effects on risks of repeat heart attacks, bleeding and death have included predominantly Caucasian patients of European ancestry," Cresci noted. "There is almost no data, until now, about these variants in African Americans."

Research examining how genetic variants alter the effectiveness of clopidogrel remains somewhat controversial, Bach said. Many physicians feel that before they can tailor medical therapy for heart attack patients, more data is needed to prove there is a clear link between genetic variants and negative health consequences and that tailoring therapy will improve patients' outcomes, he explained.

His hope is that additional research would provide more definitive conclusions to help physicians choose the best medications for patients after a heart attack and, ultimately, "to reduce the too-high rate of death and disability for patients after a heart attack," Bach said.

Cresci agreed, adding: "By focusing on genetic differences, we may be able to individualize therapies after heart attacks and achieve the best treatment for each patient."

Food poisoning cases underreported, food safety specialist says

 

June 18, 2014

Kansas State University

There are distinct symptoms for food poisoning and reporting it to your doctor is an important step in improving food safety, a food safety specialist says. According to the Centers for Disease Control and Prevention, 19,056 cases of infection were reported in 2013 in the United States. However, it is expected that many people don't report getting sick from contaminated food because they don't realize they have food poisoning.

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You've probably heard of norovirus, salmonella and E. coli, but would you know if you were sick with one of these foodborne illnesses? A Kansas State University food safety specialist says there are distinct symptoms for food poisoning and reporting them to your doctor is an important step in improving food safety.

"We really want to reduce the number of foodborne illness outbreaks," said Karen Blakeslee, extension specialist in food science and coordinator of the Rapid Response Center. "It's important to understand foodborne illness and its symptoms because the whole topic of foodborne illness is really underreported."

According to the Centers for Disease Control and Prevention, 19,056 cases of infection were reported in 2013. However, Blakeslee says many people don't report getting sick from contaminated food because they don't realize they have food poisoning. Symptoms of a foodborne illness are similar to those with other illnesses, such as vomiting, diarrhea, headache and fever, but there are some distinct symptoms of foodborne illness.

"Symptoms like double vision, dizziness, lethargy and dehydration are all symptoms specific to a foodborne illness," said Blakeslee.

It takes two or more people with similar symptoms to be considered a foodborne illness outbreak. Blakeslee says another challenge with decreasing the number of outbreaks is trying to determine the food that was contaminated.

"It's not necessarily what you ate that day or the day before," she said. "Some of the symptoms for the different kinds of bacteria may take up to a couple of weeks to occur, so that's why it makes it really hard to identify the cause of the outbreak."

If you do suspect you have food poisoning, Blakeslee says to see a doctor or call your local health department.

Early elementary school start times tougher on economically advantaged children

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Middle- and upper-class elementary school students in Kentucky demonstrated worse academic performance when they were required to start classes early, compared to peers whose school day started later (stock image).

Middle- and upper-class elementary school students in Kentucky demonstrated worse academic performance when they were required to start classes early, compared to peers whose school day started later, according to research published by the American Psychological Association.

Researchers led by Peggy S. Keller, PhD, of the University of Kentucky, theorized that earlier school start times would be associated with lower standardized test scores, poorer attendance, more students being left back, lower school rank and school underperformance. They also expected that earlier start times would be especially risky for school performance standards in more disadvantaged schools, including Appalachian schools and those with a higher percentage of students receiving free or reduced-cost lunches.

"What we found, however, was early start times were associated with worse performance in schools in more affluent districts -- that is, those with fewer kids getting free or reduced-cost lunches," Keller said. "For schools with more disadvantaged students, later start times did not seem to make a difference in performance, possibly because these children already have so many other risk factors."

The researchers examined data from 718 public elementary schools in Kentucky. Student performance was measured by looking at scores on a statewide standardized test that assessed reading, math, science, social studies and writing. They also looked at attendance rates, the number of students who were required to repeat a grade (retention rates) and teacher-student ratios. Results were published in APA's Journal of Educational Psychology.

"The relationship between earlier start times and poorer academic performance may be explained by the physical, behavioral and psychological ramifications of sleep deprivation," the researchers wrote. "Students may therefore lose the ability to remain alert and focused in the classroom." Getting less sleep might also increase the frequency and severity of illness among students, which could also lead to lagging performance, they said.

Another unexpected finding was higher rates of students repeating grades in schools with later start times. Every additional minute later a school started increased retention rates by 0.2 percent, the researchers found.

"To our knowledge, this is the first study to examine student retention in relation to school start times, and it is therefore difficult to draw firm conclusions about this finding," Keller said. "However, given that other indices of school performance were improved at later school start times, one possible explanation is that once the average students begin to improve, students with learning difficulties have an especially hard time keeping up."

Most prior research on the effect of early school start times has focused on middle and high school students, on the theory that youngsters going through puberty need more sleep. The researchers in this study concluded that research on school start times shouldn't focus exclusively on adolescents.

They also suggested that delaying middle and high school start times at the expense of making elementary school start times earlier might be a bad idea. This is sometimes done to accommodate staggered bus scheduling. "Our findings suggest that these policy changes may simply be shifting the problem from adolescents to younger children, instead of eliminating it altogether," they wrote.

Family violence leaves genetic imprint on children

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"Family-level stressors, such as witnessing a family member get hurt, created an environment that affected the DNA within the cells of the children," said lead author Dr. Stacy Drury. (Stock image)

A new Tulane University School of Medicine study finds that the more fractured families are by domestic violence or trauma, the more likely that children will bear the scars down to their DNA.

Researchers discovered that children in homes affected by domestic violence, suicide or the incarceration of a family member have significantly shorter telomeres, which is a cellular marker of aging, than those in stable households. The findings are published online in the latest issue of the journal Pediatrics.

Telomeres are the caps at the end of chromosomes that keep them from shrinking when cells replicate. Shorter telomeres are linked to higher risks for heart disease, obesity, cognitive decline, diabetes, mental illness and poor health outcomes in adulthood. Researchers took genetic samples from 80 children ages 5 to 15 in New Orleans and interviewed parents about their home environments and exposures to adverse life events.

"Family-level stressors, such as witnessing a family member get hurt, created an environment that affected the DNA within the cells of the children," said lead author Dr. Stacy Drury, director of the Behavioral and Neurodevelopmental Genetics Laboratory at Tulane. "The greater the number of exposures these kids had in life, the shorter their telomeres were -- and this was after controlling for many other factors, including socioeconomic status, maternal education, parental age and the child's age."

The study found that gender moderated the impact of family instability. Traumatic family events were more detrimental to young girls as they were more likely to have shortened telomeres. There was also a surprising protective effect for boys: mothers who had achieved a higher level of education had a positive association with telomere length, but only in boys under 10.

Ultimately, the study suggests that the home environment is an important intervention target to reduce the biological impacts of adversity in the lives of young children, Drury said.

Promising T cell therapy to protect from infections after transplant

 

June 17, 2014

Technische Universitaet Muenchen

When patients have to undergo a bone marrow transplant, the procedure weakens their immune system. Viruses that are usually kept in check in a healthy immune system may then cause potentially fatal infections. Scientists have now developed a method that could offer patients conservative protection against such infections after a transplant. The method has already been used to treat several patients successfully.

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As work with cells requires highly-pure working conditions, the scientists wear sterile clothing in the clean rooms.

When patients have to undergo a bone marrow transplant, the procedure weakens their immune system. Viruses that are usually kept in check in a healthy immune system may then cause potentially fatal infections. Scientists at Technische Universität München (TUM), together with colleagues from Frankfurt, Würzburg and Göttingen, have now developed a method which could offer patients conservative protection against such infections after a transplant. The method has already been used to treat several patients successfully.

The cells of the human immune system are created from special stem cells in the bone marrow. In diseases affecting the bone marrow, such as leukemia, the degenerate cells must be destroyed using radiation or chemotherapy. Subsequently, the hematopoietic system has to be replaced with stem cells from the blood of a healthy donor. Because of the resulting temporary weakening of the immune system, patients are more exposed to viruses that would normally be warded off.

The cytomegalovirus (CMV), which can cause serious damage to lungs or liver in persons with a weakened defense, poses a major clinical problem. In healthy human beings, a CMV infection will usually not produce any symptoms, since the virus is kept at bay by specific immune cells. In their work, the scientists were able to demonstrate that the transfer of just a few specific immune cells is sufficient to protect the recipient with the weakened immune system against infections. To do this, they used T cells that can recognize and kill specific pathogens.

Tested in an animal model

Dr. Christian Stemberger, first author of the study, and his colleagues, first isolated T cells from the blood of healthy donor mice. These immune cells were directed against molecular elements of a bacterial species which normally causes severe infections in animals. The T cells were then transferred to recipient mice that, due to a genetic modification, could no longer produce immune cells of their own -- similarly to patients suffering from leukemia.

Following the T cell transfer, the researchers infected the treated recipient mice with the bacteria. The results showed that the animals now have effective immune protection against the pathogens, preventing them from becoming ill. "The most astonishing result was that the offspring cells of just one transferred donor cell were enough to completely protect the animals," Christian Stemberger explains.

Successfully used in patients

Finally, the scientists used virus-specific T cells to treat two critically ill patients. Due to a congenital immunodeficiency and leukemia, respectively, stem cell transplants had to be performed on the two patients. Weakened by the procedure, both patients developed CMV infections.

Using a new method, the scientists therefore isolated T cells specifically programmed to target the CMV virus from the blood of the donor and transferred small numbers of these cells to the patients. After only a few weeks, the virus-specific cells proliferated. At the same time, the number of viruses in the blood dropped. "It is a great advantage that even just a few cells can provide protection. This means that the cells can be used for preventive treatment in low doses that are gentler on the organism," Dr. Michael Neuenhahn, last author of the study, explains.

The potential of the identified T cells will now be examined in a clinical study. In addition to an innovative method for cell purification, scientists also have at their disposal a new TUM facility for the sterile manufacture of cell products. In TUMCells, cells can be produced in highly-pure conditions, in so-called clean rooms. In the future, the scientists want to use recent results and TUMCells to develop innovative cell therapies.