Tuesday, November 18, 2014

The Origins of Life Could Indeed Be "Interstellar"

Some of science's most pressing questions involve the origins of life on Earth. How did the first lifeforms emerge from the seemingly hostile conditions that plagued our planet for much of its history? What enabled the leap from simple, unicellular organisms to more complex organisms consisting of many cells working together to metabolize, respire, and reproduce? In such an unfamiliar environment, how does one even separate "life" from non-life in the first place? Now, scientists at the University of Hawaii at Manoa believe that they may have an answer to at least one of those questions. According to the team, a vital cellular building block called glycerol may have first originated via chemical reactions deep in interstellar space.
Read more...

Full story at Universe Today.

Monday, November 17, 2014

Multiple Blocked Arteries Raise Questions About STEMI Treatment

Heart attacks, also known as myocardial infarctions, occur when a clogged coronary artery prevents the surrounding heart tissue from receiving an adequate supply of oxygen. Without oxygen, cardiac muscle tissue dies, impairing the heart's ability to pump blood to the rest of the body. Now, research conducted at Duke University suggests that in more than half of cases, blockages that give rise to one particular type of heart attack, the STEMI, occur to some extent in two or three arteries rather than just one. This research raises new questions about the best way to treat multiple blockages at such a precarious time.

Heart attacks are broadly separated into two categories based on their etiology and severity: STEMIs and NSTEMIs. STEMIs are characterized by an elevation of the ST-segment, one portion of the waveform on an ECG. In a healthy heart, the ST-segment represents a period of baseline electric charge that occurs in between the flood of ions in and out of the ventricles. In patients who have had a STEMI, however, the damaged heart tissue exhibits abnormal electrical activity, which manifests as an elevation of the ST-segment on an ECG. Together with laboratory tests that seek out substances released into the blood by damaged heart muscle, ST-segment elevation is a reliable indicator that a heart attack has occurred.

While informal observations have long suggested that patients who suffer STEMIs have multiple blockages in their coronary circulation, this effect had never been quantified. After formally reviewing the records of 28,000 patients who had suffered a STEMI, Dr. Manesh Patel and other members of the Duke University team found that 52.8% had two blocked arteries contributing to the infarct, and 19% had three. Additionally, Dr. Patel and his team found that those patients with more than one clogged artery had a slightly higher 30-day mortality rate (3.3%) than those with only one blockage (1.9%).

Conventional wisdom suggests that only the most pressing blockages should be treated at the time of a severe heart attack; however, given the risk for poorer outcomes among patients suffering from both a STEMI and multiple clogged arteries, researchers would do well to examine best clinical practice more closely. In Dr. Patel's words, “Our study has established that these additional blockages appear to be very common, and these patients seem to do worse, so we need additional studies to confirm these findings and then determine when and how best to open up the additional arteries to restore blood flow.” Conducting invasive procedures on a weakened heart may be a risky endeavor, but such risks may prove to be life-saving after all.

Saturday, November 15, 2014

Epidemiology at Home: On Keeping Our Infectious Diseases in Perspective

'Tis the season for medical sensationalism in the American news media. First there was the Enterovirus, or EV-D68. Soon thereafter, we witnessed the arrival of Ebola on American soil. Thanks to Ebola's notoriously high mortality rate and the devastation the virus has wrought in Africa, well-meaning public officials here in the U.S. took up a call to arms for their own citizens... and panicked. Despite the facts - first, that Ebola is very difficult to catch, requiring direct and intimate contact with the blood or body fluids of an infected an outwardly symptomatic person; and second, that medical infrastructure in an industrialized nation such as ours make it easier to successfully treat and heal an individual who does catch the virus - the general public here in America is still on edge. And, I will argue, understandably so. Ebola is a serious disease, as is EV-D68 in children with respiratory problems. But "fair and balanced" or not, mainstream news outlets are typically very good at only two things: getting clicks and generating panic.

The problem is not widespread fear over deadly infectious diseases. Instead, the problem is public perception of relative risk. Big names like Ebola and EV-D68 get a lot of press, while more low-profile, everyday diseases like Influenza end up with considerably less screen time. Meanwhile, every year our old friend Flu is responsible for millions of severe illnesses and hundreds of thousands of deaths across the globe - orders of magnitude more than Ebola and Enterovirus combined. And here's the kicker: Flu is preventable.

Flu differs from Ebola in a variety of ways, including its ease of transmission and its capacity to mutate quickly from season to season. Infected persons can transmit the disease to others up to a day or so before they begin showing symptoms. The Flu is transmitted by droplets of moisture that are expelled into the air when an infected person talks, laughs, coughs, or sneezes. Others can also pick up the disease by touching surfaces where these droplets have landed and then failing to wash their hands before wiping their nose, rubbing their eyes, or otherwise touching their face. Once inside the body, the Flu virus spreads to the respiratory tract and causes widespread inflammation, leading to the characteristic signs and symptoms within a matter of days. Usually, healthy individuals begin to feel better within a week or two; however, as with most infectious diseases, the very young, the very old, and the chronically sick or immunocompromised are the most at risk for complications from the illness. At its worst, Flu can cause exacerbation of underlying heart or lung conditions, severe pneumonia, or respiratory failure. In children, a high fever often accompanies infection with Flu and, if unchecked, can cause brief febrile seizures. Even those with an uncomplicated case of Flu can expect to feel chilly, fatigued, congested, achey, and feverish for a few days. Unfortunately, recovering from the virus once offers little protection against future Flu seasons.

Given the severity of this year's outbreak of both EV-D68 in the United States and Ebola in Africa, many concerned citizens are clamoring for the creation of protective vaccines against these diseases. Yet many of these same concerned citizens decline the Flu shot for themselves and their children, usually with one of the following explanations: "It will make me sick," "I got that one year and then I got the Flu anyway," or "Nah, it's just the Flu. I'll take my chances." Each of these statements is misguided. The Flu shot is made up of an inactivated virus, so it is incapable of making anyone sick. Even the Flu spray, which is a nasal mist version of the immunization that contains a drastically weakened version of the virus, is specifically designed to convey immunity without being strong enough to cause infection. While it is possible to contract a rare strain of the Flu even after getting the Flu shot or spray, this is uncommon. It is much more likely for an individual to catch a severe cold and mistake it for the Flu or catch the Flu itself during the vaccine's two-week immunity-building period. Lastly, the Flu is a severe illness, especially for those who are already at risk for getting sick.

So, if you are feeling troubled about the state of public health in the world today, I have one recommendation: Get your Flu shot. Although it may not completely allay your fears, checking this box off your to-do list will categorically decrease your chances of catching a potentially deadly infectious disease within the next few months. Not everyone in the world has access to that kind of protection, so use it to your advantage! Then, stay away from the blood of people who are infected with Ebola, and you will (probably) be 2 for 2.

Friday, November 14, 2014

2014 A Space Odyssey: Rosetta, Philae, and the Great #CometLanding

It is official. Humankind has successfully landed a man-made probe on a comet! On November 12th, the spacecraft Rosetta released its sister probe, a 100-kg payload named Philae, to a choreographed free-fall toward the surface of a rotating comet called 67P/Churyumov-Gerasimenko. The success of this launch is a testament to both the power of modern technology and the amazing scope of human ingenuity.

One of Philae's first images of the surface of its new home, comet 67P/Churyumov-Gerasimenko

Let's recap. Rosetta and Philae spent the last decade hurtling toward a relatively tiny, moving target at a distance of almost 600 million kilometers, course-correcting four times thanks to the gravitational influence of both Earth and Mars, successfully rendezvousing with said comet, carrying out the prescribed launch sequence, free-falling for a nail-biting 7+ hours, and finally, actually touching down on the surface in the exact spot that had been planned. Philae's initial touchdown was unexpectedly brief, however, due to the failure of its harpoons to fire and anchor it to the surface. The probe bounced three times before submitting to the feeble gravitational influence of 67P; by this time, the comet had rotated in such a way that Philae ended up resting in the shadow of a cliff, kilometers away from its planned destination. Even with a successful nudge toward a brighter area, the probe's batteries will probably lack sufficient sunlight to maintain their charge and will likely run out of juice sometime on Saturday, November 15th. Battery failure could spell the end for Philae, but all is not lost! Scientists at the European Space Agency (ESA), the organization behind the mission itself, estimate that Rosetta's landing probe will have collected and transmitted 80-90% of its data by the time its batteries are completely drained.

So what kind of data is Philae collecting, and how will the Rosetta mission help us to understand our place in the Universe? First, Philae's ten scientific instruments will tell us more about the chemical composition of 67P at varying depths, as well as its temperature, density, and magnetic properties. Complex imaging equipment has already begun returning photographs of an alien surface humankind has never seen before. Secondly, the Rosetta spacecraft will continue to orbit the comet even after Philae ceases its transmission. Over the next year, the spacecraft will accompany 67P as it approaches perihelion, or the point in its orbit when it is closest to the sun. As the comet swings through the inner solar system, Rosetta will monitor and record its increased surface activity in order to better understand what happens when comets are heated by the sun's thermal energy. Together, both Rosetta and Philae will assist scientists in building a more accurate and comprehensive picture of the physics and chemistry of comets. These insights may go on to inform theories about the origin of water and/or life in our solar system, which often feature comets as central players.

Despite their prominent role in human legend, comets have actually remained fairly mysterious to astronomers throughout history; however, thanks to modern science, Philae and Rosetta are set to revolutionize our understanding of both these icy bodies and their potentially illuminating role regarding the evolution of our planet and wider solar system. Whether Philae will be brought to life again at some sunny time in the future or whether it will soon go to sleep forever, it has done a superb job epitomizing the human drive toward adventure and discovery.

Three cheers for Philae, and for these few truly monumental days in scientific history.

Tuesday, July 1, 2014

Please Vaccinate Your Children. Sincerely, Your Friendly Neighborhood RN

(gnrhealth.com)

Look, I get it. I am one of the yuppiest hippie wannabes I know. I buy organic produce. I meticulously inspect food labels for the presence of preservatives or synthetic texturizers. I know what buzzwords to look out for in my shampoo. I frequent the Environmental Working Group's website to be sure that my cosmetics are safe. I have DIYed my own window cleaner, makeup remover and face cream. I try to only take OTC drugs when I'm feeling really, really down and out. I am one of those people who wants a doula and a midwife by my side when it comes time to have a baby. I do my best to inspect every last thing that comes near my body in the vain hope that I can out-do the mass industrialization of nutrition and personal care. My husband has born the brunt of it; I can only imagine what a madwoman I am going to turn into when we have children. So yes, I understand where you are coming from. In any other circumstance, I would be wary of agreeing to inject myself or anyone else I knew with some mystery chemical compound simply because that's what society is telling me to do.

BUT. I am also a nurse, and so I curb my neuroses when it comes to basic public health and safety. And so I'm going to say this very, very carefully: vaccines are, without question, one of the greatest, most miraculous public health accomplishments in the history of humankind. I mean it. They are up there with sewage treatment facilities, seat belts and antibiotics. Before we routinely administered today's safe, reliable vaccines, measles killed around 400 people each year. Tetanus killed around 500. Diptheria, pertussis, polio, and rubella each independently killed thousands. Keep in mind that many of those deaths were infants and young kids. And today, hundreds of thousands of men, women and children are spared these diseases, not because of better sanitation practices or better overall medical care, but because they have been immunized against them. But an increasing number of individuals - the very young, the very sick, and the very un-vaccinated - are not afforded the same protection, simply because of misinformation, mistrust and/or ignorance.

Tuesday, January 7, 2014

On the necessity of birth control in space.

The other night, John and I were browsing nerdy videos on YouTube when we happened upon one clip that discussed whether pregnancy, birth and development were possible in outer space. Given my background in astrophysics and my current pursuit of a career in OB nursing, John quickly became convinced that we had found my life's work... SPACE BABIES.

"Space Babies" Kia Sorento 2013 Super Bowl Ad

This probably isn't the start of a new and glorious career (thank you anyway, honey), but it did get me wondering about the logistics and limitations of the question. Let's say that some nice couple on the International Space Station decides that they want to have a child before their contract is up (secretly, of course, because apparently sex is expressly forbidden aboard the ISS). Would it be possible for them to conceive, and later have, a normal, healthy child?

It seems that the short answer is "no." According to research led by Joe Tash, a biologist at the University of Kansas, the high-energy radiation and so-called microgravity (10-3 G) that astronauts are subjected to during long spaceflights can have serious negative effects on their reproductive systems - namely, plummeting sperm counts and shriveling eggs. Similar concerns about the detrimental effects of space-level radiation are well-publicized. In fact, in 2010, China announced that it would require all of its female astronauts to be married with children in an effort to minimize the impact of the reproductive problems women might experience upon their return.

On the up side, a 2005 study out of the University of Texas showed that many female astronauts easily became pregnant after coming back to Earth; however, the same study also revealed a higher-than expected miscarriage rate among those pregnancies. Radiation could be to blame for these losses, but an equally plausible explanation could involve the effect of microgravity on human sex cells. Research published in 2009 in the Public Library of Science ONE showed that despite successful fertilization, many mouse embryos that were exposed to microgravity conditions stopped dividing before they reached crucial stages of development. Furthermore, Joe Tash's research also revealed severe dysfunction in the reproductive organs of female mice after about two weeks of flight aboard the space shuttle Discovery. The effect in these mice was so extensive that many of their follicular cells (the cells that produce eggs) had died and their ovaries had started to shut down.

Eek. But let's say that this daring couple is also very lucky, and they do successfully conceive a child. (We'll go ahead and skip over the logistics and precariousness of actually taking a pregnancy test in the first place.) Research suggests that while some animals, such as salamanders and fish, appear to gestate normally in microgravity environments, the outlook for mammals is decidedly more complicated. For one, some studies have suggested that microgravity can lead to fetal malformations in utero, including failure of the neural tube (the primitive brain and spinal cord) to close like it is supposed to. For another, mammals that were gestated in microgravity environments appear to have an altered vestibular response, the sense that allows a person to achieve a sense of balance and direction. Like all of our other senses, it requires stimulation to develop properly. Babies born in a microgravity environment would never learn to prefer one direction over another, leading to a compromised vestibular sense and big problems once they landed on Earth. Studies with rats have shown that a proper vestibular response can be learned over time; however, it is unclear whether that would hold true for human infants, especially if those babies spent months or even years in microgravity conditions.

And when we consider that the human body requires weight-bearing in order to stay strong, we come to another problem. Even adult astronauts have to remain vigilant about their exercise routine in order to avoid muscle atrophy and bone loss that can easily occur during long spaceflights. To a very small, rapidly developing body, these threats could be catastrophic. Additionally, the fluid shifts that commonly occur in astronauts living in microgravity environments could be far more dangerous for infants and small children, since their bodies contain more water than those of adults. Not to mention the increased risk for electrolyte abnormalities, changes in blood vessels, compromised cardiac functioning, and altered circadian rhythms that microgravity creates.

So. Overall, I think it's safe to say that conceiving, carrying, birthing, growing, or even thinking about space babies is probably not a good idea. NASA would do well to continue funding research into the effects of spaceflight on both male and female sex organs, but until we can manipulate gravity and block space-level radiation, reproduction in space just doesn't appear to be something our species is meant to experience.