Sponsored Advertisement

Friday, May 30, 2008

C-Sections Might Be Contributing To Increase In Premature Single Births, Study Says

Medically unnecessary caesarean sections might be contributing to an increased rate of premature single births in the U.S., according to a study to be published in the June issue of the journal Clinics in Perinatology, the New York Times reports. The study, conducted by researchers from the March of Dimes Foundation, Albert Einstein College of Medicine of Yeshiva University and CDC, is based on a review of birth records and previous studies. Researchers said the link between c-sections and premature single births is unclear because medical records often do not indicate why the procedure was done.

The study found that premature births increased from 9.7% of all single births in 1996 to 10.7% of single births in 2004. About 92% of the premature single births were delivered by c-section. Most premature births were considered "late preterm" births, defined as delivery between 34 and 37 weeks' gestation, according to the Times. Normal delivery is between 38 and 42 weeks' gestation. Premature infants have higher risks of breathing and feeding disorders, delayed brain development, other health problems and death, the Times reports.

Alan Fleischman, the March of Dimes' medical director and senior vice president, said obstetrics has changed so dramatically during the past 20 years that c-section deliveries and labor inductions have become commonplace. According to the Times, the c-section rate has increased steadily in recent years, from 20.7% of all births in 1996 to 30.3% in 2005. "Perhaps for convenience, perhaps out of fear of litigation, perhaps in response to a maternal request, they are scheduling their deliveries rather than allowing labor to begin," Fleischman said, adding, "And this comes when there is an epidemic in America of prematurity."

Sarah Kilpatrick, chair of the committee on obstetric practice for the American College of Obstetrics and Gynecology and chair of the Department of Obstetrics and Gynecology at the University of Illinois, said there is no proof that unnecessary c-sections are leading in premature births but added that obstetricians might "proceed with a caesarean to deliver the fetus when the fetus is probably fine" out of fear of litigation (Grady, New York Times, 5/28).

See Full Article

Sunday, May 25, 2008

Access To The Bloodstream For Kidney Dialysis Not Improved By Reducing Blockage

Reducing early blockages in bloodstream access for kidney failure treatment does not increase the likelihood that the access will function adequately for long-term treatments, according to a study funded by the National Institutes of Health. Results were published in the Journal of the American Medical Association.

"Since most of the 470,000 Americans with kidney failure depend on hemodialysis for survival, there is a clear and compelling need to evaluate therapies that reduce or prevent access failure," said NIH Director Elias A. Zerhouni, M.D. "These results tell us we need to keep looking for solutions."

Hemodialysis filters waste and extra fluid from the bloodstream and requires a vascular access - a site on the body where blood is removed and returned. Fistulas are the preferred type of access since they clot less often, experience fewer infections, and are less costly; patients with fistulas also have lower mortality. A fistula is created by joining a section of an artery and a vein to make one large vessel capable of handling high volumes of blood during hemodialysis. But maintaining any access site is a major clinical challenge. Blood clotting in the fistula is the most frequent cause of early fistula failure. Clotting, infection and low blood-flow rates in the access site are common reasons for hospitalizations requiring multiple treatments or surgeries. Click here to read about vascular access.

The Dialysis Access Consortium (DAC) found that only 12 percent of patients developed blood clots in the fistula when treated with the clot-preventing drug clopidogrel, compared to nearly 20 percent of patients treated with placebo. Nevertheless, about 60 percent of new fistulas in each group could not be used for long-term dialysis treatments. Complications such as bleeding were similar across the study groups.

DAC studied nearly 900 patients at 9 U.S. medical centers in academic and community practices in urban and rural settings. Participants received a new fistula and took the anti-platelet drug clopidogrel (Plavix) or a placebo tablet daily for 6 weeks to determine if the drug would maintain blood flow in fistulas and increase the number suitable for dialysis.

"Because vascular access is critical for delivering lifesaving care, we are already organizing another multi-center study to look for other ways to improve fistulas," said co-author Catherine M. Meyers, M.D., a kidney specialist in charge of DAC at NIH's National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), which funded the study.

The DAC Fistula Trial is the largest multi-center trial to look at preventing blood clots in new fistulas and the first to test whether prevention would allow more fistulas to be usable for dialysis. NIDDK has funded DAC since 2000. Clopidogrel and placebo were donated by what is now Sanofi Aventis/Bristol-Myers Squibb.

The National Institute of Diabetes and Digestive and Kidney Diseases, a component of the NIH, conducts and supports research in diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition, and obesity; and kidney, urologic, and hematologic diseases. Spanning the full spectrum of medicine and afflicting people of all ages and ethnic groups, these diseases encompass some of the most common, severe, and disabling conditions affecting Americans. For more information about NIDDK and its programs, see http://www.niddk.nih.gov/.

The National Institutes of Health (NIH) - The Nation's Medical Research Agency - includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov/.

Source: Mary Harris
NIH/National Institute of Diabetes and Digestive and Kidney Diseases

Patients With Acute Kidney Injury Do Not Have Improved Outcomes With More Intensive Dialysis

No significant difference in death rates or other outcomes was found between a group of patients with acute kidney injury that received intensive dialysis and another group that received a more standard regimen of dialysis, according to a joint Department of Veterans Affairs (VA) and National Institutes of Health (NIH) study published in the June issue of the New England Journal of Medicine. Acute kidney injury, also called acute renal failure, is a common complication in hospitalized patients that is associated with very high mortality rates. In-hospital mortality rates of critically-ill patients typically range from 50 percent to 80 percent.

Several prior single-center studies in patients with acute kidney injury had suggested improved survival with more intensive dialysis, which is significantly more costly to administer. "We now have definitive evidence that intensive treatment of acute kidney injury is no more beneficial in improving treatment outcomes than the usual level of care," said NIH Director Elias A. Zerhouni, M.D. "As a result, the findings of this well-designed study may help prevent unnecessary medical expenditures."

Within 60 days after starting dialysis, 302 patients (53.6 percent) in the intensive treatment group died compared to 289 patients (51.5 percent) in the less-intensive treatment group. Also, the study reports no significant differences between the two groups in recovery of kidney function, the rate of failure of organs other than kidneys, or the number of patients able to return to their prior living situations.

No medications have been found to be effective in treating acute kidney injury, so doctors use hemodialysis and other forms of renal-replacement therapy to support patients whose kidneys do not function properly. Hemodialysis uses a machine to clean waste and extra fluid from the blood when the kidneys can't do the job.

In this study, doctors provided renal-replacement therapy to both patient groups. Patients who did not require medications to maintain their blood pressure were treated with conventional dialysis, either three times per week in the less-intensive arm of the study or six times per week in the intensive arm. Patients who were unstable and required medications to increase their blood pressure were treated with more gentle forms of dialysis, either a slower form of hemodialysis called SLED or a continuous form at a lower or higher dose as randomly assigned. Patients were able to switch between forms of therapy as their clinical condition changed, while remaining within the lower or higher intensity treatment arms of the study.

"The main purpose of this study was to see if intensive therapy would reduce the death rate, shorten the duration of the illness, and decrease the number of new complications in other organs among patients with acute kidney injury," said co-author Robert A. Star, M.D., director of NIDDK's Division of Kidney, Urologic and Hematologic Diseases. "Though this was found not to be the case, it is important that we know this so we can focus future research on finding more beneficial treatment strategies."

"Unlike earlier studies that used only a single method of therapy, our use of an integrated strategy of continuous and intermittent methods of therapy allows us to apply these study results more readily to clinical practice," explained study chair Paul M. Palevsky, M.D., chief of the Renal Section at the VA Pittsburgh Healthcare System and a professor of medicine at the University of Pittsburgh School of Medicine. "What is important about these results is that they outline the limits of effective therapy."

See Full Article

Wednesday, May 21, 2008

Sleep Apnea Raises Risk Of Low Blood Oxygen During Air Travel

People who have obstructive sleep apnea are more likely to have low blood oxygen and experience higher physiological stress (which can raise heart risk) during air travel than people who do not suffer from the condition, suggesting they may need extra oxygen during flight, like patients with chronic lung diseases.

The study was the work of Leigh Seccombe, MSc, of Concord Repatriation General Hospital in Sydney, Australia, and colleagues, and was presented on Sunday 18th May 2008 at the annual meeting of the American Thoracic Society in Toronto, Canada.

Obstructive sleep apnea (OSA) is a common condition where a person's breathing pauses during sleep because of an obstruction in their airway.

In this study, Seccombe and colleagues investigated the physiological response of 22 patients with severe OSA and without lung disease, to a simulation of an aircraft cabin and compared it to that of 10 healthy subjects.

The researchers measured the participants' ventilatory response (the volume of air going in and out of the lungs), and also the amount of oxygen circulating in their bloodstream.

In the simulator, the participants were exposed to the equivalent of cabin air at 6,000 ft (16.8 per cent O2) and 8,000 ft (15.1 per cent O2).

The results showed that:

* Half of the 22 OSA patients would need supplemental oxygen when flying, if current guidelines issued to patients with lung disease were to be followed.

* There was no difference in the ventilatory response change with increasing simulated cabin altitudes between the OSA and the healthy group.

* But in the OSA group only, the oxygen uptake and heart rates were significantly higher than they would be at "sea level".

* Oxygen demand in the OSA group went up from 0.3 liters per minute at sea level to just under 0.4 l/m at 8,000 feet.

The researchers concluded that:

"Patients with OSA, without lung disease, are more likely to develop significant hypoxemia [low blood oxygen] and have increased oxygen demands during flight. Ventilatory response was not impaired."

Speculating on their findings, Seccombe told MedPage Today that it was too early to say what the clinical implications might be:

"Many people fly, many people get hypoxic, but not many have adverse events," said Seccombe, adding that one explanation could be obesity, since the average BMI (body mass index) of the OSA participants was 36 compared to 24 for the healthy participants.

See Full Article

Blood Donation More Risky For Teenagers

Compared to older blood donors, sixteen and seventeen year olds are much more likely to experience complications related to donation, such as fainting and bruising. This was published in a study in JAMA published on May 21, 2008.

According to the authors, blood donation centers are continuously challenged with finding more safe blood as donors dwindle. They write: "The unremitting need and increasing demand for blood components constantly challenges blood centers to maintain a safe and adequate blood supply from a decreasing pool of eligible donors that is now estimated at only 38 percent of the U.S. adult population." To find eligible donors, blood centers have advocated several measurements for recruitment, including legislation allowing the collection of blood from donors aged 16 to 17 years in states that do not presently allow it. Of the American Red Cross's present donations, 14.5% of come from the 16 to 19 year old group annually, according to the article.

It has previously been suggested that younger donors are more susceptible to complications from donation. To investigate this, Anne F. Eder M.D., Ph.D., of the American Red Cross, Washington, D.C., and colleagues examined the adverse reactions experienced by 16 and 17 year olds. Data was collected in 1996 from nine American Red Cross blood centers which regularly collect donations from this age group, which comprises approximately 80% of donations in high school blood drives. In this time, 145,678 whole blood donations were collected from 16- and 17-year-olds (group 16-17), 113,307 from 18- and 19-year-olds (group 18-19), and 1,517,460 from donors age 20 years or older (group 20+).

Complications, including loss of consciousness or bruising, were present in 10.7% of donations made by 16-17, 8.3% made by 18-19, and 2.8% made by 20+. In comparison to 18-19 and 20+, the 16-17 group was more likely to experience some loss of consciousness or major complications. Injuries directly related to fainting were not common, and for every 10,000 blood collections there were 86 events in group 16-17. That said, this was 2.5 more likely in this group than group 18-19, and 14 times more likely than in group 20+. Almost half of all injuries in total occurred in sixteen and seventeen year old donors. Many episodes required outside medical care, including many involving concussion, laceration involving stitches, dental injuries, or broken jaw.

These complications correlated repeat donor rates. Sixteen year old donors with even minor complications were 60% less likely to return to donate within 12 months in comparison with those who experienced no complications (52% versus 73% return rate). The researchers write that this likely influenced donors interest in returning: "Consequently, any negative experience diminishes the likelihood of return blood donation, and increases the possibility that a short-term yield in donations incurs the ultimate expense of deterring future blood donation by young donors. These findings are particularly pertinent at a time when blood centers are becoming increasingly reliant on young donors to maintain an adequate blood supply. "

They conclude, stating that these results should be considered in the application of new legislation. "These data on common and infrequent complications of blood donation should be considered when age limits are deliberated by state authorities. The relatively comparable reaction rates in 16- and 17-year-old donors, and their increased complication rates compared with young adults and adults, suggest the need for a consistent approach. Blood centers have an obligation to constantly monitor risks of blood donation and to make a concerted and committed effort to achieve the lowest possible rate of complications. Although zero risk may not be attainable even in adults, the rate of complications in minors calls for ongoing attention to a sustained operational effort that is continually focused on donation safety."

See Full Article

Friday, May 16, 2008

7 Steps to control Migraine

Author: Raeburn Forbes MD

This assumes your diagnosis is correct. If you are not sure of your diagnosis you are advised to speak to your doctor.

Migraine affects 16% of women and ^5 of men. If you are a practicing nurse, it is inevitable that you will care of someone who has migraine and they may ask you about how to control them. Here's my 7 steps....

Step 1 - Sleep

Sleep has been recognized as a treatment for migraine. Many people with migraine take to their bed, as it is the only way to get comfortable. Sleep will inevitably follow, and it is a common experience to waken with your head feeling a lot better - if not completely gone.

An irregular sleep pattern and sleep deprivation can trigger migraine attacks. If you are able to do so, try and improve your sleep hygiene - wind down before bedtime, have a milky drink, make sure your day is active enough that you feel tired, avoid stressful situations - it is common sense really.

Step 2 - Water

Dehydration - a lack of water - can make migraine more likely to occur. A recent study looked at drinking habits and found that those who keep hydrated, were less likely to experience migraine attacks. I'd suggest aiming for about 1-2 pints extra each day (500 to 1000ml) on top of what you routinely drink. Please note that if you have kidney trouble, you may not be able to be free to increase your fluid intake by this amount - check with your doctor if you are unsure.

Step 3 - Exercise

It is a commonly accepted fact that exercise causes naturally made painkillers (called endorphins) to be released into your brain. While a direct link cannot be proven, it seems likely that regular exercise will contribute to a sense of well being, and that when you feel fit, headaches are less likely to occur. A problem is that migraine people can sometimes cause headaches by exercising too much, especially if tired or dehydrated or if exercising in bright sunlight. I'd suggest starting with gentle exercise such as walking half to one mile a few times each week, then building this up until you enjoy walking 2 or 3 miles at a time. Walk interesting routes, go with a friend, anything to make you stick to the routine. You do not have to train to run a marathon, but regular exercise, I'm sure, is a big help.

Step 4- Diet & Weight Management

There is no end to the amount of information written about diets. A lot of people talk about triggers such as coffee or chocolate. If you find that a specific food always produces a migraine, then it makes sense to avoid it. However, if you analyze a trigger food, you may find that when you ate the chocolate you were a bit underslept, had missed your lunch, were under a bit of stress and it was a warm day when you hadn't had much to drink. No wonder when you took that mid-afternoon snack of chocolate, you ended up with a migraine! My advice is this - eat regularly, try to avoid missing meals. When you eat - enjoy it! Better to enjoy your food and relax than get stressed over what is supposed to be one of life's simple pleasures.

If you do happen to be overweight, reducing your weight through a planned calorie restriction and exercise program can reduce the amount of headache you have.

Step 5 - Stress avoidance

This is hard. You are a young mother, holding down a job, your partner works long hours, you have deadlines, need to keep the house running, children or parents to sort out etc etc etc. This sort of common stress can take its toll. More major stress will also provoke headaches. Learning to deal with stress is difficult. However, I often find that people who get stressed are usually very bad at looking after themselves - when did you last take a few hours off just for yourself? Stress avoidance is helpful.

Step 6 - If you get a migraine take a medicine that is likely to work

There have been lots of studies on migraine treatment over the years. The tried and tested medicines can be obtained from your pharmacist (chemist) without prescription. These include (for adults) Aspirin, anti-emetics (metoclopramide, buclizine), non-steroidals (ibuprofen, naproxen), and some combinations that also contain caffeine. These will get about 50% to 75% of people with a migraine episode nearly pain free in 1-2 hours in most cases. There are specific migraine drugs that can usually be obtained on prescription only - called triptans, the commonest of which is sumatriptan. Any tablet for a migraine attack works best if taken as early as possible. I usually recommend that you take a painkiller or triptan as soon as you think "oh no, it's one of these rotten headaches again". If you leave it too late, you may have 'missed the boat' and will have to put up with the pain and take to your bed.

Step 7 - A preventative medicine that works.

There are several medicines which will reduce the number of migraine episodes if taken every day. They usually fall into one of three categories:

· beta-blockers (also used in treating blood pressure or angina)

· anti-convulsants (also used for treating epilepsy or chronic pain)

· anti-depressants (also used for treating depression!)

It is not clear how these drugs work, but if used at low doses on a regular basis, they can minimize the number of migraine headaches you have.

So that's it - 7 steps to controlling migraine - exactly what I tell my patients. Note that a lot of this is within your own control - sleep, exercise, water intake, diet, stress avoidance - it is a powerful thing to feel in control. Medicines will help, but unless you look after yourself, medicines are not the whole answer.

You can download a free copy of this article 7 Steps to Treat Your Migraine. Right click, then click 'save target as..', and you can save to your computer.

If you use this article, please be courteous enough to make sure you acknowledge the author and websites.


Raeburn Forbes MD(Hons) is a practicing neurologist from Northern Ireland. He runs medical information websites in his spare time including www.lumbarpuncture.net and www.migrainenews.co.uk

Monday, May 12, 2008

Virus Hijacks Cell Division Machinery

Viruses are masters of deception, duping their host's cells into helping them grow and spread. A new study has found that human cytomegalovirus (HCMV) can mimic a common regulatory protein to hijack normal cell growth machinery, disrupting a cell's primary anti-cancer mechanism.

Writing in the May 9 issue of Science, researchers from the University of Wisconsin-Madison and Harvard Medical School report that a viral protein, called UL97, masquerades as a normal regulatory enzyme to modify a tumor-suppressing protein in human cells. Unlike the normal enzyme, which can be switched on and off by the cell as needed, the viral stand-in lacks an off switch and evades cellular control. The findings represent a previously unknown way that viruses can cause uncontrolled cell growth and division.

Cells normally have tight regulatory mechanisms in place to limit multiplication to appropriate situations, such as replacing worn-out cells or repairing damage. Uncontrolled cell proliferation can lead to cancer and other disorders.

One of the most important cellular control mechanisms works through a protein called the retinoblastoma tumor suppressor protein, which slows cell growth.

"The retinoblastoma pathway is like the brakes on a car. It prevents tumor cells from growing out of control," says Robert Kalejta, an assistant professor in the UW-Madison Institute for Molecular Virology and McArdle Laboratory for Cancer Research, who led the new study. "This pathway is mutated in essentially all human cancers."

Disrupting this pathway is also advantageous for viruses. Unable to reproduce on their own, viruses rely on co-opting their host's cellular machinery, like an occupying army taking over a local factory. They are especially good at overriding or bypassing built-in control mechanisms, Kalejta says.

"Viruses are well known to encode proteins that have similar activities to cellular proteins, but they're just different enough that they're beneficial to the virus," he says. "[UL97] shares the same activities as the cellular protein, but it lacks all of the control mechanisms."

In essence, UL97 disables the brakes and hits the gas. Once a host cell is primed toward growth, HCMV takes over and steals the cell's machinery to reproduce itself.

The virus's bloodhound-like ability to seek out and target the most essential pieces of a cell's machinery makes it a valuable research tool, Kalejta says.

"Viruses are smarter than we are. They know a lot more about cells than we do, because their life depends on it - they're obligate intracellular parasites," he says. "If they attack a part of the cell - a process or a protein - you know it's important for the cell. If the virus pays attention to it, you should too."

Kalejta next hopes to use UL97 to find other proteins that may be important for cell growth. He also sees potential clinical applications down the road. HCMV infection is very common and, though it remains asymptomatic in most people, it has been implicated in some cancers and can cause trouble in people with compromised or suppressed immune systems, such as AIDS patients and transplant recipients. In addition, UL97-like proteins are also found in the other seven human herpes viruses, some of which are directly linked to cancers.

The advantages of the research are two-fold, Kalejta says. "We're studying a virus that causes human disease and might eventually find a way to treat that infection and help patients. At the same time, we're learning about how the cell works, which has implications for patients that don't have infections," he says. "You get two for the price of one."

See Full Article

Sunday, May 11, 2008

Sexual Health Screening Without Mention Of Sex

Young women would accept age-based screening for the sexually transmitted infection chlamydia, but would want this test to be offered to everyone, rather than to people 'singled out' according to their sexual history.

In the study, published in the BioMed Central open access journal BMC Infectious Diseases, the Australian women interviewed did not like discussing their sex lives with their GPs. Some said they would even lie about how many sexual partners they had if asked. In response to these findings, the study authors suggest that a detailed sexual history should not be required before testing women for chlamydia.

Chlamydia is Australia's and the UK's most commonly diagnosed sexually transmitted infection (STI). It is most prevalent in the under-25s and can have serious long-term health consequences, including causing infertility in women.

A team comprising three doctors, a sociologist and an epidemiologist at the University of Melbourne, Australia aimed to find out what young Australian women thought about the introduction of chlamydia screening into general practice. The researchers interviewed 24 sexually active women aged 16 to 24 who attended one of a sample of general practices. Equal numbers of women from rural, regional and urban areas were questioned.

In contrast to previous research, which suggests women are not concerned about giving information about their sexual history in the context of a family planning or sexual health clinic, interviewees were reluctant to provide such a history to their GPs. This is a new finding which raises the question of whether a sexual history is really necessary when screening for chlamydia.

The authors acknowledge that it is important for young women to understand that chlamydia is an STI and that sexual partners should be notified if someone tests positive. However, they said that chlamydia testing should be destigmatized. "In general practice the offer [of a chlamydia test] may seem to come 'out of the blue'" says Natasha Pavlin, who coordinated the study. "The importance of normalizing the offer of chlamydia testing, so that individual women do not feel singled out, cannot be overemphasized."

See Full Article

New Technique Measures Ultrashort Laser Pulses At Focus

Lasers that emit ultrashort pulses of light are used for numerous applications including micromachining, microscopy, laser eye surgery, spectroscopy and controlling chemical reactions. But the quality of the results is limited by distortions caused by lenses and other optical components that are part of the experimental instrumentation.

To better understand the distortions, researchers at the Georgia Institute of Technology developed the first device to directly measure complex ultrashort light pulses in space and time at and near the focus. Measuring the pulse at the focus is important because that's where the beam is most intense and where researchers typically utilize it. Knowing how the light is distorted allows researchers to correct for the aberrations by changing a lens or using a pulse shaper or compressor to manipulate the pulse into the desired form.

"Researchers have always measured the pulse immediately as it exited the laser, so they didn't realize the extent to which the pulse became distorted by the time it reached the focus after traveling through the optics and lenses in the system," said Rick Trebino, a professor in the Georgia Institute of Technology's School of Physics and Georgia Research Alliance Eminent Scholar in Ultrafast Optical Physics.

The device was described in a presentation at the Conference on Lasers and Electro-Optics on May 8. This research was funded by the National Science Foundation and published in the August 2007 issue of the journal Optics Express.

It is difficult to measure ultrashort pulses because they typically last between a few femtoseconds and a picosecond, which are 10-15 and 10-12 of a second, and faster than the response time of the fastest electronics.

"The light comes out as a train of extremely short bursts. The laser crams all of the energy of a continuous laser into a few femtoseconds, which creates really intense laser pulses," said Pam Bowlan, a graduate student supported by the Technological Innovation: Generating Economic Results (TI:GER) program.

To achieve the highest possible intensity of the laser, the pulse must be as small as possible in space and as short as possible in time. However, focused pulses nearly always have distortions in time that vary significantly from point to point in space due to lens aberrations in focusing optics.

To address those issues, the new device, called SEA TADPOLE (Spatial Encoded Arrangement for Temporal Analysis by Dispersing a Pair of Light E-fields), allows researchers to measure complicated ultrashort pulses simultaneously in space and time as they go through the focus.

"A lot of chemists and biologists use ultrafast lasers, so it was important that our device be easy to use because non-laser scientists don't want to spend all day measuring their laser pulses," noted Bowlan.

The research team - which also included former graduate students Pablo Gabolde and Selcuk Akturk - used the concept of interferometry to measure a pulse in space and time. Two pulses, one reference and one unknown, were sent through optical fibers. The fibers were mounted on a scanning stage so that the pulses could be measured at many locations around the focus.

The pulses were crossed and an interference pattern was recorded for each color of the pulse at each location with a digital camera. The patterns were used to determine the shape of the unknown pulse in space and time and to create movies showing how the intensity and color of the pulse changed in space and time as it focused.

"Because the laser pulses enter SEA TADPOLE through optical fibers, which only collect a very small portion of the light, the device naturally measures pulses with high spatial resolution and can measure them at a focus spot size smaller than a micron," explained Bowlan. To further improve the spatial resolution of the device, the research team began to use specialized fibers, called near-field scanning optical microscopy fibers, which can resolve features smaller than the wavelength of the light.

The researchers tested the device by measuring ultrashort pulses focused by various lenses, since each lens can cause different complex distortions. To validate the measurements, Bowlan performed simulations of pulses propagating through the experimental lenses. Results showed that a common plano-convex lens displayed chromatic and spherical aberrations, whereas more expensive aspheric and doublet lenses exhibited mostly chromatic aberrations.

Spherical aberrations occur when the light that strikes the edges of the lens gets focused to a different point than the light that strikes the center, creating a larger, inhomogeneous focused spot size. Chromatic aberrations occur because the many colors in the laser travel at different speeds and do not stay together in space and time as the pulse passes through glass components in the experimental setup, such as lenses. As a result, each color arrives at the focus at a different time, creating a rainbow of colors in the electric field images.

Aberrations can drastically increase the pulse length, which decreases the laser intensity. A lower intensity forces researchers to increase the power of the laser, increasing the possibility of damaging the sample. Aberrations can also yield odd pulse and beam shapes at the focus, which complicate the interpretation of the experiment or application.

"Our system tells researchers what types of aberrations are present in instrumentation, which then allows them to test different lenses in the instrumentation setup or use a pulse shaper to create the desired pulse at the focus that's free of distortions," added Bowlan.

See Full Article

Wednesday, May 7, 2008

Women Who Quit Smoking Quickly Reduce Heart Risk But Lungs Take Longer

Women who quit smoking significantly reduce risk of death from coronary heart disease within 5 years, but impact on risk of death from lung and other cancers take longer.

These are the findings of Dr. Stacey A Kenfield, of the Harvard School of Public Health, Boston, USA, and colleagues in a new study published in the May 7th issue of the Journal of the American Medical Association, JAMA.

According to the World Health Organization, about 5 million deaths were smoking related in 2000, and estimates suggest that by 2030, this figure will rise to 10 million worldwide, 7 million of which will be in developing countries, wrote the authors, who also said that tobacco use is the leading cause of death in the United States.

But while the link between smoking and increased risk of death from a range of diseases has been well established, the effect of quitting compared to continuing to use tobacco has not.

Kenfield and colleagues examined data from the Nurses' Health Study on over 100,000 women who were followed from 1980 to 2004. In this group there were nearly 12,500 deaths, with nearly 4,500 among never smokers (36 per cent), 3,600 among current smokers (29 per cent) and just under 4,400 among past smokers (35 per cent).

They calculated the relative risks (as hazard ratios) among the three subgroups of death from any cause, and from specific diseases such as cardiovascular, respiratory, lung and other cancers, and other causes.

The results showed that:

* There was a 13 per cent reduction in the risk of death from any cause within the first 5 years of quitting compared to continuing to smoke.

* This risk reduced to the same level as the never smokers after 20 years of quitting.

* Within this overall 20 year figure some causes took less time to go down to the never smokers' risk level and others took longer.

* Vascular disease showed the most rapid reduction in risk to the never smokers' level, with much of it showing in the first 5 years of quitting.

* These included coronary heart disease (62 per cent of excess risk gone in first 5 years of quitting) and cerebrovascular disease (42 per cent of excess risk gone in first 5 years of quitting).

* These figures were obtained from comparing the hazard ratios of recent quitters of less than 5 years with long term quitters of 20 years or more.

* Death from respiratory diseases showed an 18 per cent reduction in risk of death 5 to 10 years after quitting, going down to the never smokers' level after 20 years.

* Risk of death from lung cancer showed a significant 21 per cent reduction in the first 5 years of quitting compared to continuing to smoke, but the excess risk did not go away for 30 years.

* Past smokers who had quit for 20 but less than 30 years, had an 87 per cent reduction in risk of death from lung cancer compared to current smokers.

* When risk of death from other smoking-related cancers was included, this figures approached the never smokers' risk level more than 20 years after quitting.

* Risk of death from all causes, respiratory diseases, and smoking related cancers, was significantly higher among women who started smoking at a younger age.

* The figures also showed smoking was linked to increased risk of death from colorectal cancer but not ovarian cancer.

* About 64 per cent of deaths among current smokers and 28 per cent among past smokers were linked to cigarette smoking.

The authors concluded that:

"Most of the excess risk of vascular mortality due to smoking in women may be eliminated rapidly upon cessation and within 20 years for lung diseases."

They added that:

"Postponing the age of smoking initiation reduces the risk of respiratory disease, lung cancer, and other smoking-related cancer deaths but has little effect on other cause-specific mortality. These data suggest that smoking is associated with an increased risk of colorectal cancer mortality but not ovarian cancer mortality."

The researchers emphasized the importance of maintaining school programs on preventing tobacco use and enforcing laws that deny young people access to tobacco, given that early initiation is linked to higher risk of death. They also wrote that:

"Effectively communicating risks to smokers and helping them quit successfully should be an integral part of public health programs."

See Full Article

Breast Cancer Radiotherapy: A Possibility For Fewer Doses

Breast cancer patients can receive radiotherapy in a lower overall dose, given in fewer, larger administrations, while maintaining similar tumor control and creating fewer adverse side effects than current therapy. These conclusions come from the United Kingdom's Standardization of Breast Radiotherapy Trials A and B (START A and B), and were released on March 19, 2008 in Lancet Oncology and The Lancet respectively.

The international standard radiotherapy schedule for early breast cancer administers 50 Grays (Gy) of radiation total, separated into 25 small fractions of 2.0 Gy over five weeks. Cancer specialists have long believed that, when delivered in fewer, larger fractions, a lower total dose could be as safe and effective as this standard.

The START trials collaborative group, including Professor John Yarnold, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey, UK, and Professor Judith Bliss, Clinical Trials and Statistics Unit, Institute of Cancer Research, Sutton, UK, and colleagues from 35 UK cancer centers investigated this option. The study took ten years, and was jointly funded by Cancer Research UK, the UK Medical Research Council, and the UK Department of Health.

START A was comprised of 2,236 women with early breast cancer at 17 different centers in the UK. They were randomly assigned, after primary surgery to one of the following groups:

* 34% (749 women) to receive 50 Gy total in 25 fractions of 2.0 Gy each, the highest total dosage and the international standard;
* 34% (750 women) to receive 41.6 Gy total in 13 fractions of 3.2 Gy each, the intermediate total dosage;
* 33% (737 women) to receive 39 Gy total in 13 fractions of 3.0 Gy each, the lowest total dosage.

Treatment was administered in all groups over a five week period. Women were considered eligible if they were over 18 years of age, did not have immediate surgical reconstruction, and were available for follow up. The endpoints of the trial were: tumor relapse, which was defined as cancer reappearance at the sites which were irradiated; any effects of the treatment on normal or "cancer free" tissues; and effects on the quality of life for the patient.

After a median follow up of 5.1 years, tumor relapse at five years was 3.6% for the highest total dosage group (50 Gy), 3.5% for the intermediate total dosage (41.6 Gy) and 5.2% for the lowest total dosage group (39 Gy.) Late adverse effects and local tumor relapse rates for the highest and intermediate total dosages were similar, which in the lowest dose the absolute difference could range from 1.3% better to 2.6% worse in the lowest dose group. Patient self-assessments as well as photographic surveys indicated that there were lower rates of late adverse effects in the lowest dosage group than in the highest.

In conclusion to the START A study, the authors state that this modification to the international standard regimen could have promise: "A lower total dose (41·6 Gy) in a smaller number of fractions could offer similar rates of tumor control and normal tissue damage as the international standard fractionation schedule of 50 Gy in 25 fractions."

START B tested 2,215 women with early breast cancer at 23 centers in the UK. They were also randomly assigned after primary surgery, but to one of the following groups:

* 50% (1105 women) to receive 50 Gy total in 25 fractions of 2.0 Gy each, over 5 weeks, the international standard;
* 50% (1110 women) to receive 40 Gy total in 15 fractions of 2.67 Gy each, over 3 weeks, a lower total dose and a shorter administration period.

Just as in START A, women were considered eligible if they were over 18 years of age, did not have immediate surgical reconstruction, and were available for follow up. Additionally, the measured endpoints of the trial were: tumor relapse, any effects of the treatment on normal or "cancer free" tissues, and effects on the quality of life for the patient.

In a median follow-up of 6.0 years, the rate of tumor relapse at five years was 2.2% in the shorter and lower total dosage group and 3.3% in the international standard group. Statistically, this represents an absolute difference ranging from 0.9% worse and 1.7% better in this group from the standard. Photographic evidence and patient self-assessments both confirmed that lower rates of adverse events were seen after the lower, shorter dose.

From these results of the START B study, the authors conclude that this lower dose in combination with the shorter total administration time can also yield comparable results to the presently used standard: "After surgery for early breast cancer, a radiotherapy schedule delivering 40 Gy in 15 fractions over three weeks seems to offer local regional tumor control and rates of late normal tissue effects at least as good as the accepted international standard of 50 Gy in 25 fractions over five weeks."

Dr. Harry Bartelink, Netherlands Cancer Institute, Amsterdam, Netherlands, and Dr. Rodrigo Arriagada, Institut Gustave Roussy, Villejuif, France, contributed an accompanying comment in which they note the merits of this new therapy while caution against sudden changes in in the international standard treatment regimen: "We realise that hypofractionation is convenient for patients, because it reduces the number of visits to radiotherapy departments and waiting lists in several cancer centers. Nevertheless we have to wait for data on longer follow-up before final conclusions can be drawn from the START trials."

See Full Article

Mo. Appeals Court Rules On Challenge To Ballot Summary Of Stem Cell Research Ban

The Western District of the Missouri Court of Appeals on Friday ruled that part of a ballot summary for an initiative to limit stem cell research prepared by Secretary of State Robin Carnahan (D) is "unfair and insufficient," the AP/Columbia Missourian reports. According to the AP/Missourian, the court's ruling is "largely symbolic" because supporters of the measure did not plan to continue gathering signatures to place the initiative on the November ballot. The group Cures Without Cloning would have needed to gather about 150,000 signatures by Sunday. The group said it now will try to place the initiative on the 2010 ballot (Marshall, AP/Columbia Missourian, 5/2).

The proposal would have continued an existing prohibition on human cloning but would have banned a particular kind of embryonic stem cell research -- called somatic cell nuclear transfer -- that is allowable under a constitutional amendment narrowly approved by Missouri voters in November 2006. Carnahan's original summary said the proposal would "repeal the ban on human cloning or attempted human cloning to criminalize and impose civil penalties for some existing research, therapies and cures." Cole County, Mo., Circuit Court Judge Patricia Joyce in February effectively rewrote the language of the initiative's summary and largely adopted the language suggested by Cures Without Cloning (Daily Women's Health Policy Report, 2/22).

The appellate court's opinion, written by Judge Lisa White Hardwick, agreed with Joyce that Carnahan's use of the word "repeal" was insufficient and unfair. However, the appellate court did not agree that Joyce should have rewritten the entire summary.

Both supporters and opponents of the ballot proposal lauded the ruling, the AP/Missourian reports. Carnahan's office in a statement said that the ruling "validates our summary statement as fair and accurate, while only replacing one word." Cures Without Cloning officials said they are pleased that part of Carnahan's statement was ruled insufficient and unfair but added that they plan to appeal the ruling to the state Supreme Court because the appeals court did not rule that Carnahan violated the group's constitutional rights (AP/Columbia Missourian, 5/2).

Reprinted with kind permission from http://www.nationalpartnership.org. You can view the entire Daily Women's Health Policy Report, search the archives, or sign up for email delivery here. The Daily Women's Health Policy Report is a free service of the National Partnership for Women & Families, published by The Advisory Board Company.

See Full Article

Saturday, May 3, 2008

A New Method To Establish The Antioxidant Capacity Of Extra Virgin Olive Oil

A group of scientists from the Nutrition and Food Science Departments from the Faculty of Pharmacy of the University of Granada have reported the beneficial effects of extra virgin olive oil on human health, determining in vitro and in vivo the antioxidant power that the examined extra virgin olive oil samples present. With this work, researchers have discovered a more effective method in order to establish the antioxidant capacity of extra virgin olive oil.

Research has been directed by doctors M. Carmen López Martínez, Herminia López García de La Serrana and José Javier Quesada Granados, and its main author is Cristina Samaniego Sánchez. The scientists have prepared four methods to determine the antioxidant capacity and the beneficial effect of the extra virgin olive oil obtained from olives of the Picual variety.

Work "in vitro"

In order to carry out this work, they determined the best method to calculate the in vitro antioxidant capacity in oil samples. They concluded that, among all the applied methods, the ABTS was the most suitable in order to study this kind of samples as it shows the correlation with the total polyphenol index in a better way. Moreover, scientists observed that the reproducibility of the results of these methods is good and that the variation coefficients obtained by the different methods are acceptable, which makes it possible to conclude, generally, that the four studied methods could be applied to measure the antioxidant oil capacity.

Scientists from Granada are not discarding the idea of registering some patents related to this research soon, since they already have experience in getting patents related to other studies on food, such as alcoholic drinks. Their research is applicable to every kind of olive oil, and these methods could be used in the areas where olive groves are cultivated, regardless of the variety of olive used in the oil obtaining process.

See Full Article

Two Groundbreaking Scientists Share America's Largest Medicine Prize

America's largest prize for work in medicine, amounting to half a million dollars, is shared this year by two scientists, Elizabeth Blackburn of the University of California, San Francisco and Joan Streitz of Yale University, for their groundbreaking work in molecular research that opens up development of new and effective treatments for a range of diseases.

This is the first time that women have received the prestigious Albany Medical Center Prize in Medicine and Biomedical Research.

Blackburn is Morris Herzstein Professor of Biology and Physiology at UCSF. She has a worldwide reputation for her pioneering work on telomeres, the DNA sequences at the end of chromosomes (the "bookends" that hold everything together). She discovered the ribonucleoprotein enzyme telomerase, which strengthens telomeres.

Before this research, the "clock" of cellular life was a mystery to scientists. Telomeres becomes progressively shorter over the life of a cell and when they become too short, the cell dies. Blackburn showed that telomerase can add DNA back to the ends of telomeres and effectively turn back the clock.

Blackburn's more recent work with psychology has shown a link between low levels of telomerase and chronic stress that can lead to early onset of a range of age-related conditions such as neurodegenerative and cardiovascular diseases. She also hopes to find out if it is possible to stop cancer by manipulating telomerase.

President and chief executive officer of Albany Medical Center, James J. Barba, who chaired the National Selection Committee, said:

"Dr. Blackburn's studies of this fascinating enzyme and its effect on cellular aging may hold the key to prolonging life by helping to treat a variety of diseases and disorders from cancer to chronic stress."

Steitz is Sterling Professor of Molecular Biophysics and Biochemistry at Yale. She achieved global recognition when she found out how small ribonucleoproteins (snRNPs) behave in pre-messenger RNA, the earliest product of DNA transcription. She discovered that snRNPs get rid of introns, the useless chunks of DNA and pre-messenger RNA, by "splicing" them out and then joining the severed ends together to make messenger RNA. Messenger RNA then instruct the production of proteins, the essential building blocks of the body's biology.

Steitz's work shed light on the formation of proteins, and especially on the intricate transformations that occur as the immune system and brain develop. Understanding more about the "splicing" function of snRNPs may lead to discoveries about how to prevent many human diseases.

Barba said that:

"Many scientists believe that Dr. Steitz's research may ultimately lead to breakthroughs in treating a variety of autoimmune diseases including lupus."

"Dr. Steitz and Dr. Blackburn are among the greatest scientists of our generation. The potential impact of their research is extraordinary and we all owe them a great debt of gratitude," he added.

The Albany Medical Center Prize in Medicine and Biomedical Research started in 2000 with a 50 million dollar endowment from the Marty and Dorothy Silverman Foundation to enable the prize to be given annually for 100 years. The late Morris "Marty" Silverman was a businessman from New York.

See Full Article