Study points to rethink of red blood cell storage duration

A small study from Johns Hopkins adds to the growing body of evidence that red blood cells stored longer than three weeks begin to lose the capacity to deliver oxygenrich cells where they may be most needed.

In a report published online in the journal Anesthesia & Analgesia, the Johns Hopkins investigators say red cells in blood stored that long gradually lose the flexibility required to squeeze through the body’s smallest capillaries to deliver oxygen to tissue. Moreover, they say, that capacity is not regained after transfusion into patients during or after surgery.

“There’s more and more information telling us that the shelf life of blood may not be six weeks, which is what the blood banks consider standard,” says study leader Steven M. Frank, M.D., an associate professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine. “If I were having surgery tomorrow, I’d want the freshest blood they could find.”

Frank acknowledges that blood banks do not have enough fresh blood for everybody, and that shorter storage periods would result in diminished inventory. But he says that the current practice of transfusing blood stored up to six weeks may need to be reconsidered.

One previous, large study published in the New England Journal of Medicine has already shown that cardiac surgery patients who received blood stored longer than three weeks were almost twice as likely to die as patients who got blood that had been stored for just 10 days.

doi: 10.1213/ANE.0b013e31828843e6



New hypothesis on why bacteria increasingly resistant to antibiotics

In a revolutionary article published in the journal “Archives of Microbiology”, a researcher from the University of Granada (Spain) provides an answer to an enigma that scientists have still not been able to solve.

According to his theory, bacteria that are non-resistant to antibiotics acquire said resistance accidentally because they take up the DNA of others that are resistant, due to the stress to which they are subjected.

A University of Granada researcher has formulated a new hypothesis concerning an enigma that the scientific community has still not been able to solve and which could revolutionise the pharmaceutical industry: Why are bacteria becoming increasingly more resistant to antibiotics? His work has revealed that the use of antibiotics can even cause non-resistant bacteria to become resistant because they take up the DNA of others that are already resistant.

Mohammed Bakkali, a scientist in the Genetics Department at the Faculty of Science of the UGR, maintains that our abuse of antibiotics “forces” the bacteria to take up the DNA of other bacteria that are resistant to said antibiotics, since the presence of antibiotics exposes them to a great stress. According to the researcher, “In this way, the non-resistant bacteria become resistant completely by accident on ingesting this DNA and can even become much more virulent, partly due to the stress we subject them to when we make an abusive use of antibiotics”.

For decades, scientists from all over the world have been researching into when, how and why bacteria take up DNA from other antibiotic-resistant bacteria, thus becoming also resistant. The answers as to when there is DNA uptake (in unfavourable or stressful circumstances) and as to how the bacteria take it up are clear, but, up until now, “nobody has pinpointed the reason why bacteria ingest this genetic material”, as Bakkali points out in an article published in the latest edition of the journal “Archives of Microbiology”.

Under normal conditions, a bacterium could have a lot to lose if it ‘decides’ to take up DNA, since it does not have a ‘DNA reader’ enabling it to take up only those molecules that are of use to it and the most likely is that this DNA will be dangerous, or even lethal.

They do not want that DNA, because they break it up

In his article, Mohammed Bakkali argues that, in reality, bacteria do not look for DNA to take up (they appear not to ‘want’ this DNA, since they are constantly degrading it; in other words, breaking it up) and that this uptake is a chance event and the sub-product of a type of bacterial motility that is part of its response to the stress that the bacteria may be subjected to.

Therefore, our current indiscriminate use of antibiotics “not only selects the resistant bacteria, but also means that the bacteria take up more DNA, due to their increased motility in response to the stress that the antibiotic subjects them to”. The result is that the stress caused by the antibiotic itself induces the uptake of genetic material that can bring about resistance to the antibiotic by bacteria that, otherwise, would not have taken up that DNA nor become resistant to the antibiotic. Furthermore, this effect is strengthened by its lack of specificity, since it occurs both in the target pathogen and in other bacteria.

The UGR researcher states that, when a bacterium takes up DNA from another antibiotic-resistant one (and which could have died due to another environmental factor), the bacterium that takes it up becomes resistant to that antibiotic. “Thus, the bacteria can go on adding to their arsenal of resistance to antibiotics and end up being resistant to a wide range of them, such as is the case of the multi-resistant strain of astaphylococcus, called Staphylococcus aurius, which creates havoc in many operating theatres.



Brain stent offers alternative to shunt for pseudotumor cerebri

A team of interventional neuroradiologists and neurosurgeons at Johns Hopkins reports wide success with a new procedure to treat pseudotumor cerebri, a rare but potentially blinding condition marked by excessive pressure inside the skull, caused by a dangerous narrowing of a vein located at the base of the brain.

The study, published in the Journal of Neuro-Ophthalmology online March 14, is believed to be the first to show how directly lowering pressure inside the vein alleviates the condition and improves vision.

The study on 12 patients describes the team’s novel use of intravascular ultrasound imaging to delicately thread an expandable metal stent, roughly two inches long and attached to a catheter, through an opening in the groin, all the way to the main blood vessels in the neck and shoulders draining fluid from the brain. The goal is to precisely position the stent across the narrowed portion of the vein, called the transverse sinus, where it expands, allowing blood to drain more freely and relieving fluid pressure in the brain. The vein narrowing, or stenosis, is considered to be the leading cause of pseudotumor cerebri. The condition earned its name, which translates to “false” tumour of the brain, because in the era before detailed brain imaging became available, surgeons used to operate on people with similar optic nerve swelling, suspecting brain tumours, yet they would find none.

Because the transverse sinus drains cerebrospinal fluid, constriction of the vessel causes fluid backup and raises intracranial pressure, which, if left untreated, can lead to permanent damage to the optic nerve, blurred vision and eventual blindness.

According to lead study investigator and Johns Hopkins interventional neuroradiologist Martin Radvany, M.D., the new, minimally invasive procedure, known as transverse sinus stenting, takes about two hours to perform, and could serve as a long-term, if not permanent fix to what he says is a vexing and growing problem, seen mostly in obese, premenopausal women between the ages of 18 and 40.

“Our study results, if validated in more patients, give us more than an alternative to shunts and bypassing the consequences of pseudotumor cerebri,” says study coinvestigator and interventional neuroradiologist Philippe Gailloud, M.D. “Our latest research helps us get to the root of the problem so that we can stop and possibly prevent the vein from narrowing in the first place,” says Gailloud, who is also director of interventional neuroradiology at Johns Hopkins.

A video of one of the patients having the procedure is available on YouTube. www.youtube.com/watch?v=__M9v1FEHfs



Stem cells produce regenerated bone in mandible transplants

Bone transplantation is a major strategy for the repair of bone defects. However, reconstruction of the mandible (jawbone) has long been a difficult challenge for oral surgeons – at least up to now. A new study in Stem Cells Translational Medicine shows how stem cells can be used to successfully repair the mandible after a molar extraction and, years later, the new bone is still functioning properly.

Interestingly, the regenerated bone is also hard, rather than the spongy kind normally found in the jaw.

The new study is a follow-up to previous investigations by an international team of researchers in which they discovered that mesenchymal stem cells taken from dental pulp and seeded on a collagen scaffold successfully repaired the mandible bone. In this latest work, they checked on patients who had received the mandible bone grafts three years earlier to assess the stability and quality of the regenerated bone and vessel network.

They found the new bone had normal function and was richly vascularized, although was much more compact than the spongy type normally found in the mandible. The team theorized that, most probably, regeneration of compact bone occurs because grafted dental-pulp stem cells do not follow the local signals of the surrounding spongy bone.

“Dental pulp is an interesting source of ready-to-use stem cells to treat bone defects,” said Anthony Atala, M.D., Editor of Stem Cells Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. “The finding that these cells regenerate compact bone in the mandible indicates a potential role in the treatment of oral cancer.”



Landmark global study shows cardiac benefits of Mediterranean diet

People who eat a plant-based Mediterranean diet supplemented with nuts or virgin olive oil can enjoy long-term benefits that can include a 30% reduction in the risk of cardiovascular disease, according to a landmark global study released at the sixth International Congress on Vegetarian Nutrition hosted by Loma Linda University Health, recently.

The study, to appear in the New England Journal of Medicine, involved 7,447 individuals (55-80 years old) at high risk of cardiovascular disease but with no symptoms.

The results favour two Mediterranean diets (one supplemented with nuts, the other with virgin olive oil) over a low-fat diet for beneficial effects on intermediate outcomes that include body weight, blood pressure, insulin resistance, blood lipids, lipid oxidation and systemic inflammation.

The study, called “PREDIMED” for “PREvención con Dieta MEDiterránea” (Prevention with Mediterranean Diet) began in 2003 and was completed in 2011. Participants were followed for an average of 4.8 years.

“The aim of PREDIMED was to determine whether a plant-based Mediterranean diet, supplemented with either tree nuts such as walnuts, almonds and hazelnuts or virgin olive oil, when compared to a low-fat diet, can help prevent cardiovascular diseases such as cardiovascular death, heart attack and stroke,” said Dr Miguel Angel Martinez of the University of Navarra, Spain, a lead investigator of the study, which was released simultaneously in Loma Linda and Spain.

“What we found was that a Mediterranean diet offers a preventive efficacy that was also assessed on secondary variables, including death from all causes, and incidence of diabetes and metabolic syndrome,” added Martinez, a physician, epidemiologist and nutrition researcher.

The Mediterranean diet is a pattern of eating similar to the traditional dietary habits of people living in the countries bordering the Mediterranean Sea. This includes fresh fruits and vegetables, seafood, whole grains and nutritious fats, including walnuts and olive oil.

“This study is a prime example of the type of international research being shared at this conference of 800 academics, researchers, dieticians and others dedicated to advancing research about the benefits of plant-based diets,” said Dr Joan Sabaté, chair of the International Congress on Vegetarian Nutrition and chair of the Department of Nutrition at Loma Linda University’s School of Public Health.

Sabaté served as principal investigator in a nutrition research study that directly linked the consumption of walnuts to significant reductions in serum cholesterol. His findings were published in the New England Journal of Medicine in 1993.

“Twenty years ago we released a study showing the health benefits of nuts,” Sabaté said. “Now, the results of a trial, also released at Loma Linda, further demonstrate that a plant-based diet, infused with nutritious unrefined plant fats, can have long-lasting effects for heart health and a productive and a productive life.”



What makes a nurse’s day?

A small group of experienced nurses were asked to describe the characteristics of an extraordinary day at work. The one universal theme was ‘making a difference’. The authors say it is important for managers to know what motivates nurses in order to avoid costly staff burnout and turnover. ‘Making a difference’ did not necessarily mean saving a life or even a positive clinical outcome but improving care for patients and/or their family. The authors call for more research in the area.

Nurses asked to describe what makes a day at work extraordinary say it is making a difference to patients, even if that difference isn’t as grand as saving a life, according to researchers from the United States. Writing in the journal Nursing Management the authors, from Bristol Hospital in Bristol, Connecticut, say that knowing what motivates nurses is important for healthcare managers.

“To prevent costly nursing burnout and turnover, hospital managers need to create environments that foster satisfaction. To achieve this they must understand what nurses want in a job and if this changes over time, but at present this is undefined and elusive.”

Other reasons nurses offered for an extraordinary day included being able to ‘teach somebody something’, working well with colleagues as a team, and establishing a good relationship with the patient and their family.

But a typical comment from one of the nurses was: ‘The days I am most disappointed are those days where I feel like I made no difference at all... when it comes to just a plain old ordinary day and one that’s extraordinary it’s that - making a difference.”

An extraordinary day for the nurses in the study did not necessarily depend on a good clinical outcome either, say the authors.

One nurse explained: “I think being able to accept your death is one of the biggest parts of life, and I’m impacting that person’s life... their life... their choice to die and I’m making it better... If I can make an angry family into an accepting family... when the patient and family do well, that means the world to me.”

The authors say the results of their qualitative study are not generalisable but add that it is a step towards learning what nurses value.

They suggest more qualitative studies are necessary to enable nurses to say in their own words what they find meaningful about their jobs.



Protein in malaria parasite may be new target for drug treatment

Scientists have discovered how a protein within the malaria parasite is essential to its survival as it develops inside a mosquito. They believe their findings identify this protein as a potential new target for drug treatments to prevent malaria being passed to humans.

The researchers found that when this protein – a transporter responsible for controlling the level of calcium inside cells – is absent during the parasite’s sexual reproduction stages inside a mosquito, the parasite dies before developing fully. They discovered that the calcium transporter protein is responsible for protecting the parasite from potentially lethal levels of calcium during these stages.

The findings suggest that new drug treatments could be developed to target the parasite’s sexual reproduction stages. These, unlike most current anti-malarial drugs, would block transmission of the parasite from human to mosquito, disrupting the cycle of infection.

The study was led by Dr Henry Staines at St George’s, University of London and Dr Rita Tewari of the Centre of Genetics and Genomics at the University of Nottingham. It has been published in the journal PLoS Pathogens.

doi: 10.1371/journal.ppat.1003191


 

                                  
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