'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.
Showing posts with label biology. Show all posts
Showing posts with label biology. Show all posts
Saturday, November 15, 2014
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.
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.
"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.
Sunday, January 16, 2011
Not quite Jurassic Park, but close.
15,000 years ago, North America was close to unrecognizable. Most of modern-day Canada and parts of what is now the United States were covered by glaciers and temperatures elsewhere easily averaged below freezing. In the midwest, enormous mammals and birds reigned supreme. One of the most well-known of these massive species was the wooly mammoth. Their stature is believed to have been comparable to today's elephants; however, their hind legs were significantly shorter than their front legs, their colossal ivory tusks often measured over 13 feet in length, and, as you may have guessed, they were exceptionally hairy. Now, Japanese scientists have hatched a plan to bring this ancient beast back to life.
Back in 1996, researchers shocked the world when they unveiled Dolly, the very first test-tube ewe. Dolly lived to be six years old, and has long been hailed as the ultimate triumph of biotechnology. But can the same be done with an extinct species from the last ice age? Allegedly yes, through the process of somatic cell nuclear transfer (SCNT).
In SCNT, scientists extract an egg cell from a live animal and remove its nucleus, replacing it with the nucleus of a somatic cell (a somatic cell is any cell not from a sex organ). Somatic cells are diploid cells, meaning that they have two copies of genetic material from the parent animals. Germ cells, such as egg cells, are called haploid because they only have one copy. Replacing the nuclear material from an egg cell with that of a somatic cell is therefore an effective simulation of fertilization. Once the egg has been modified, it can then be implanted in a surrogate uterus, where it divides to form an embryo.
The research team hopes to isolate an intact somatic cell from frozen remains of a wooly mammoth. Within five or six years, they plan to successfully replace the nucleus of an elephant's egg cell with the nucleus of this preserved mammoth cell, implant it into the uterus of an elephant, and wait patiently for the birth of an animal that has not existed since humanity's first predecessors roamed the earth. No sweat. For some biologists, raising the dead is all in a day's work.
Back in 1996, researchers shocked the world when they unveiled Dolly, the very first test-tube ewe. Dolly lived to be six years old, and has long been hailed as the ultimate triumph of biotechnology. But can the same be done with an extinct species from the last ice age? Allegedly yes, through the process of somatic cell nuclear transfer (SCNT).
In SCNT, scientists extract an egg cell from a live animal and remove its nucleus, replacing it with the nucleus of a somatic cell (a somatic cell is any cell not from a sex organ). Somatic cells are diploid cells, meaning that they have two copies of genetic material from the parent animals. Germ cells, such as egg cells, are called haploid because they only have one copy. Replacing the nuclear material from an egg cell with that of a somatic cell is therefore an effective simulation of fertilization. Once the egg has been modified, it can then be implanted in a surrogate uterus, where it divides to form an embryo.
The research team hopes to isolate an intact somatic cell from frozen remains of a wooly mammoth. Within five or six years, they plan to successfully replace the nucleus of an elephant's egg cell with the nucleus of this preserved mammoth cell, implant it into the uterus of an elephant, and wait patiently for the birth of an animal that has not existed since humanity's first predecessors roamed the earth. No sweat. For some biologists, raising the dead is all in a day's work.
Sunday, October 10, 2010
Scientia Pro Publica 42: The Ultimate Answer to the Ultimate Question of Life, The Universe, and Everything.
That's right! I am proud to present to you this particular edition of Scientia Pro Publica, your ULTIMATE guide to the best science, nature and medical writing on the web... the best, that is, until next week.
Let’s get started with the obvious: we all think science is pretty cool, or we wouldn’t be here. Self-proclaimed science lover Julie links us to some great resources to celebrate our collective appreciation of nature (and rockets!) in her posts World Space Week! and A New Website for Rocket Lovers over at Mama Joules. For some more fun, check out Sailing by Starlight: The Lost Art of Celestial Navigation at Southern Fried Science. There, Andrew teaches us all a lesson about living without navigational equipment. That's right. No Google maps, no GPS, no atlas or street names or landmarks; just you, the sea, and the sky.
Saturday, June 26, 2010
Was there once life on Venus?
Of our two planetary neighbors, Mars was always the favored child, making headlines year after year as scientists alternately bolstered and debunked claims of its habitability. Meanwhile, Venus sat idly by - gaseous and fuming, nothing but a bright "star" in the early morning and evening skies. But all that might be about to change. For the last four and a half years, the Venus Express satellite has been gathering data that suggests that, at one time, the gassy planet may have supported liquid water.
Image courtesy of NASA.
Today, Venus is an oppressive and stormy place. With an ambient temperature hot enough to melt lead, surface pressure comparable to the depths of Earth's oceans, and an atmosphere composed mainly of carbon dioxide and sulfuric acid, Venus is an inconceivably inhospitable place for life to thrive. However, this was not always the case. The Venus Express satellite has detected large amounts of hydrogen and oxygen escaping into space from the Venusian atmosphere; more specifically, two molecules of hydrogen for every one molecule of oxygen. Sound familiar? It should. Liquid water, or H2O, shares this exact ratio and evaporates into its constituent gases when struck by UV light from the sun. Current research implies that most of this water was probably atmospheric, but it does not rule out the possibility of ancient oceans on the Venus' surface. Water is thought to be a crucial ingredient for the evolution of carbon-based life forms, making the existence of standing water on Venus at some point in history appealing to astrobiologists studying the origin of life in the solar system.
Image courtesy of NASA.
Today, Venus is an oppressive and stormy place. With an ambient temperature hot enough to melt lead, surface pressure comparable to the depths of Earth's oceans, and an atmosphere composed mainly of carbon dioxide and sulfuric acid, Venus is an inconceivably inhospitable place for life to thrive. However, this was not always the case. The Venus Express satellite has detected large amounts of hydrogen and oxygen escaping into space from the Venusian atmosphere; more specifically, two molecules of hydrogen for every one molecule of oxygen. Sound familiar? It should. Liquid water, or H2O, shares this exact ratio and evaporates into its constituent gases when struck by UV light from the sun. Current research implies that most of this water was probably atmospheric, but it does not rule out the possibility of ancient oceans on the Venus' surface. Water is thought to be a crucial ingredient for the evolution of carbon-based life forms, making the existence of standing water on Venus at some point in history appealing to astrobiologists studying the origin of life in the solar system.
Friday, June 25, 2010
Physiology of a Suntan, or Why I Am So Red.
Image courtesy of Vox Efx.
As I lay out in the blazing 100-degree sun today, I started wondering exactly what was happening to my skin on the microscopic level. Welcome to my nerdy daydreams. As it turns out, my mental image of thousands of tiny cellular defenders banding together in formation to fire missiles at hoards of incoming free radicals isn't quite right.
As we all know, sunburns and suntans are caused by the sun's ultraviolet radiation (UVR). There are two types of UVR that can penetrate the earth's atmosphere: UVA and UVB. UVA rays are the most prevalent, no matter the season or time of day, and are responsible for wrinkles, sunspots, mottled, droopy skin, and other signs of aging.
Skin cells under a microscope. Image courtesy of euthman.
UVB rays, on the other hand, are responsible for sunburns and suntans. Upon contact with UVB light, skin cells called melanocytes begin producing melanin, a pigment that darkens the skin and absorbs harmful radiation before DNA damage can occur. UVB rays prompt the secretion of MSH, or Melanocyte Stimulating Hormone, from the pituitary gland. MSH binds to a receptor on the surface of melanocytes, triggering melanogenesis through the release of a chemical called cAMP. The more cAMP that is present, the greater the amount of melanin that is synthesized. Once melanin is released from the melanocytes, it is transferred to surface skin cells called keratinocytes that darken and give skin its tanned appearance. In fair-skinned individuals, MSH cannot bind to its receptor as effectively, so less melanin can be produced. With less melanin, UVB rays can easily strike melanocytes and keratinocytes, causing nuclear damage and inciting an inflammatory response, which we call a sunburn. Generally speaking, Caucasians have less melanin than other, darker-skinned populations and so tend to have higher incidences of sunburn and skin cancer.
Take it from me, the fair-skinned hypocrite who forgot to reapply her sunscreen today: sun damage takes its toll over time and can even be fatal. Take action to protect your skin, and keep those nasty photons away from your melanocytes.
Subscribe to:
Posts (Atom)