Mama, You Are A Mythical Beast

The Chimera, a fire-breathing creature of Greek Mythology and what I feel like after a rough day with my one and two-year-old children.

Most moms I know would agree that they feel profoundly altered by motherhood.  As a witty friend of mine said, “it’s like Kafka’s ‘The Metamorphosis’ without the exoskeleton.”  We can all identify the scars, stretch marks or sagging appendages that are our badges of motherhood, but the change is more profound than that. I felt my sense of self was shattered, reassembled and seemed to expand to include my children.  While I often day dream about spending a weekend as my former carefree, kid-free self, when I actually get that weekend off kid duty I wander around feeling out of sorts.  I enjoy myself, but I have this surreal feeling that I have left behind something really important- like a limb.  It maybe a cliché to say that your children will always be a part of you, but there is a reason for the cliché: it rings true for a lot of people.  It turns out it may be true in a more literal way than you’d imagine.

For a long time scientists thought of the placenta as a selective barrier between mom and baby that allowed certain things, like oxygen and nutrients to be exchanged, but never cells.   Now we know that this is not the case.  In fact, mother and baby exchange small numbers of cells during pregnancy.  The astonishing thing is that these cells persist for decades and often a lifetime.  Researchers have found baby’s cells in mother’s heart, liver, kidney, brain and other organs long after she has given birth.  Likewise, babies receive cells from their mothers, for instance some types of immune cells, although this phenomenon is less well studied.  This means that both mother and baby are technically “chimeras” which is the medical term for an organism that is composed of two or more genetically different populations of cells.  The term originates in Greek mythology in which the Chimera was a fire-breathing female creature that was part lion, snake and goat.  Because we are talking about very small numbers of cells in these cases, the term “microchimerism” is used.

One of the remarkable things about microchimerism is that it challenges the conventional notion of how the immune system works.  A simple, but not totally inaccurate way to sum up the modus operandi of the immune system is to say that it identifies agents as “self” or “non-self” and then destroys anything that is “non-self.”  But if a small number of baby’s cells live on in mother’s body, why doesn’t her immune system react to them? In some cases it might.  Scientists are researching the possibility that microchimerism is the reason women are more prone to autoimmune diseases than men, and the incidence of some of these diseases increases in their post-reproductive years.  Perhaps, because exchange of cells between mother and baby is normal, the immune system has mechanisms to avoid attacking these “non-self” cells, but in some cases these mechanisms fail, leading to diseases like scleroderma or multiple sclerosis.  Researchers are also investigating possible links between microchimerism and certain cancers, as well as Alzheimer’s disease.  But microchimerism probably isn’t all bad news for mom.  There is some evidence that suggests that babies’ cells may help protect mothers from breast cancer and repair injured tissues.  The study of microchimerism is really just beginning and more research needs to be done before the role of microchimerism in health and disease can be understood.  But if microchimerism does play a role in disease, this research may help scientists develop more effective treatments.

I trained as a biologist and I still tend to look at the world as a biologist does.  When I think about “who I am” I think of myself as a product of my genes and my experiences.  But now I know that as a mother, my body harbors the cells and genes of my children.  Through their cells I have also acquired some of my husband’s genes.  Of course I am also a daughter and therefore I contain cells from my mother who passed away too young.  I am excited to see what science discovers about what role, if any, these cells play in my body, but microchimerism fascinates me for sentimental reasons as well.  All of these people that I love are not only figuratively “in my heart,” but tiny bits of them are literally in my body.  They will always be a part of me- no matter what happens.  There is something so satisfying about that.

You can learn more about microchimerism research by visiting www.microchimerism.org

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Mama, You Are A Mythical Beast

When N= 1, Reason= 0

The title of this essay is admittedly a craven attempt to attract the attention of scientists and closet geeks- you know who you are.  For the non-geeks reading this, N is the symbol for sample size or “the number of units in a population to be studied.”  In this case, N= 2 because the “units” in question are my kids and my “study” addresses the intersection of science, the media and parenting.  Or maybe I should say the three-car pile-up.

If you become a parent, you are required to make a lot of choices for your young kids.  Many of these are inconsequential, like will my kid wear overalls or sweatpants, pigtails or a pixie-cut? But many of the important choices have to do with health science issues such as circumcision, immunization, breast milk vs. formula- the list goes on and on.  If you are a geek like me, your first impulse is to research each issue, make your choice and prepare your argument for anyone who questions you (and believe me they will.)  It usually goes something like this “Well, recent studies have shown that yada yada yada…”  Then you pat yourself on the back for being so informed and making a well-reasoned decision.

The trouble begins when you finally graduate or stop working at a university and the powers that be cut off your online library access (the bastards!)  What are you to do without the magic of PubMed or ISI Web of Knowledge?!?   What happens when you can’t get your hands on peer-reviewed scientific journal articles?  You console yourself with the fact that we live in the “Information Age.”  Surely, with Google, a fast internet connection and the myriad forms of mass media available, you should be able to find the information necessary to make well-reasoned, science-based decisions for your children.

Maybe not.  A friend (thanks Andy Jones!) recently shared an article with me entitled “Why Most Biomedical Findings Echoed by Newspapers Turn Out to be False: The Case of Attention Deficit Hyperactivity Disorder.”   (By the way, this article is from the PLoS One, a peer-reviewed, online, open-access publication put out by the Public Library of Science non-profit.  If you are missing your primary literature fix, check it out.)  The gist of the article is that the news media preferentially cover initial findings described in the most prominent scientific journals.  The key word there is initial.  When a scientist gets some really interesting results, she publishes them along with her methods so that other scientists can do their own version of the experiment and try to replicate the interesting result.  If these subsequent studies fail to get the same result, it suggests that the initial study was flawed in some way.  There are myriad ways even a well-done study can be flawed so this replication of results is an essential part of the scientific process and in theory, these subsequent studies are just as important as that initial study.  But in practice, sadly, many of these subsequent studies don’t get published in the most prominent journals because they are not “a big scoop.”  The trouble is that a lot of these subsequent studies end up showing that the initial exciting finding was wrong (or at least overblown.)  In the case of ADHD described in the article above, three of the 10 initial findings they considered were totally refuted and four were attenuated by subsequent studies.  But since these subsequent studies are published in less prominent journals, they are less likely to be covered by the mass media, and those of us living outside the ivory tower are less likely to learn about them.

That brings us to a case that really pushes my buttons- childhood immunizations.  In 1998, Dr. Andrew Wakefield and colleagues published a study in the prominent British medical journal the Lancet, claiming to link the MMR (measles, mumps, rubella) vaccine with autism.  The scientific community immediately pointed out a number of glaring flaws in the study and subsequent studies over the next decade failed to reproduce his results, but it was too late- the popular media, and popular celebrities like Jenny McCarthy, had already latched on. Parents were terrified, vaccination rates dropped and we started having outbreaks of diseases like measles, mumps and whooping cough, which can be deadly.  Yes, subsequent studies that found no link between vaccines and autism were covered by the media- but they received less attention. Because let’s face it, scary headlines get more attention.  The Lancet retracted the article twelve years after its publication and in 2011 a British investigative journalist demonstrated that Wakefield actively falsified data.  Still, to this day vaccination rates have not fully recovered and many scared parents are still misinformed and paranoid about vaccinating their children.  At the 2012 Super Bowl there was an outbreak of measles, primarily among children who had not been vaccinated.  Only 14 individuals were sickened, but if vaccination rates continue to decline, then these types of events will increase in frequency and scale.

Admittedly, the MMR case is an extreme example of the media over-reporting a mis-leading scientific result. Very few scientific studies are retracted and few scientists falsify data.  And it is okay for a scientific study to be (honestly) wrong, that is why the subsequent studies are so important and why we don’t make public health decisions based on the results of one study.  Yes, this is a reductionist summary of the whole to vaccinate or not vaccinate issue.  Not all vaccines are created equal and the arguments for or against them should be taken individually- I don’t really want to get into that whole debate here.  But the MMR-autism controversy is a great example of one initial study and the ensuing media hysteria having a major impact on parents.

So I am sure you can see I am being a bit self-righteous here.  Here I am strutting my formally trained scientist status claiming “I would never be fooled by such hysterical nonsense!”  Well, nonsense.  I am fooled.  I am fooled by the fear that comes with being a parent.  This is the fear that comes with being responsible for defenseless little humans who you love more than anything in the world.  This is the fear that comes with acknowledging all the bad things that can happen to them that you have no control over.  One (of the many) big bad things hiding in my closet is schizophrenia.  A member of our family developed schizophrenia suddenly at age 17 and has not recovered.  Schizophrenia can run in families, so my two children may have up to a 4% chance of developing this disease as opposed to the 1.1% chance that someone with no direct relatives has.

So along comes my March 2012 issue of The Atlantic Magazine featuring an article entitled “How Your Cat Is Making You Crazy” by Kathleen MacAuliffe.  I would have found this article fascinating even if schizophrenia weren’t the boogeyman in my closet, because I am just that kind of weird.  The subject of the article is a parasite called Toxoplasmosis gondii, a protozoan, that usually cycles through two hosts: cats and rodents.  Toxo as I’ll call this beast, starts life as an egg in a cat, that is pooped out, finally moving out of its parent’s cat and setting out to find a cat of its own.  How does it get into a new cat?  Cats, unlike dogs, are pretty fastidious creatures and don’t tend to eat or otherwise mess around with other cat’s poop.  So Toxo gets itself into a less fastidious, but tasty morsel like a mouse instead, hoping to get into a cat if the mouse becomes a kitty dinner.  But mice can find a lot of ways to die and Toxo really wants to get into a cat, so it ups the odds by getting into the mouse’s brain and changing its behavior. The mouse goes from a cautious, life-loving rodent to behaving a bit like a character on that MTV show Jackass.  The mouse’s activity level increases (cats love to chase fast moving objects) and it may become less wary in exposed areas and attracted to the smell of cats.  How does Toxo make the mouse behave like it has a death wish?  It does it by manipulating dopamine, a neurotransmitter in the brain.  Very cool.  (By the way, my summary of the article here does not do it justice.  I recommend clicking on the link and reading it for yourself.)

The trouble is that Toxo does not always find its way into a mouse.  Humans can also become infected when they come in contact with cat poop, eat undercooked meat or unwashed veggies grown in a garden where cats poop.  We have known for a long time that becoming infected with Toxo while you’re pregnant can be very harmful to the baby so pregnant women have been warned off cleaning kitty litter boxes or eating nasty food.  But healthy, non-pregnant adults infected with Toxo weren’t thought to suffer any detrimental effects- until recently.  MacAuliffe’s article focuses on the work of a Czech biologist named Jaroslav Flegr, whose research suggests that Toxo may alter behavior in humans as well.  Flegr’s data suggests a variety of behavioral changes including a reduction in fearfulness and response times.  In most people, these purported behavioral shifts are probably very subtle and unremarkable.  But Flegr suggests that in some unlucky people, Toxo infection serves as the trigger for mental illness, for instance schizophrenia.

The theory among many researchers is that schizophrenia occurs as a result of an interaction between a person’s genes and their environment.  You may have the unlucky genes for schizophrenia, but never develop it because there is no environmental trigger during your life that causes those genes to malfunction.  You may even be able to develop schizophrenia without being genetically predisposed to it, if you have the right combination of environmental triggers. There is a long list of potential environmental triggers including:  childhood stress, prenatal famine, drug abuse and infections with diseases like Toxo.

I am over-simplifying the genetics of schizophrenia and the gene-environment interaction theory here.  I am not an expert on the epidemiology of schizophrenia, but I did briefly try to become one with the help of Google after I read MacAuliffe’s article.  Reading this article set me off on a tear of worrying.  We have a cat, but I wasn’t worried about her.  She is an indoor cat (we love birds) and there is a very low incidence of Toxo infections in indoor cats.  But our neighbors have outdoor cats and there are feral cats in our neighborhood, which sometimes hang out in our yard, where my kids like to play in the dirt and eat things out of the garden, including the dirt itself.  Shit.

I took to Google and researched cat traps and repellants, how to get your kids to wash their hands, etc.  I lay awake at night for hours strategizing about how to keep my home and yard Toxo free.  And then I realized, even if I managed to exclude all cats from my yard and the totally impossible feat of getting my kids (ages 1 and 2) to wash their hands before they touched their faces or food EVERY time, I was still doomed.  My kids would go to friend’s houses and play in their Toxo infested yards.   The only toddlers who wash their hands that diligently probably have OCD, and mine suffer from many behavioral problems, but not that one.

Toxo was something I couldn’t control and I needed to let it go.  At our next check-up I talked to our pediatrician about it, who had never heard about the potential Toxo-schizophrenia link.  She graciously concealed her “oh Lord, another parent with a loony theory” reaction and calmed me down.  As she put it, my only real option to prevent Toxo infection was to never allow my children to play outdoors or in the dirt, and the detrimental effects of that were likely far greater than the risk of schizophrenia, Toxo or no Toxo.  She also reminded me that this potential link between Toxo and schizophrenia is a fairly initial finding and not totally understood. Science and medicine are always making new discoveries.  30 years from now we may find out that feeding kids broccoli causes obsessive compulsive disorder and parents will begin beating themselves up about that.  You just can’t go there.  Or as my father the doctor advised:  If you’re going to worry, worry about them when they start driving.  So I started worrying about that 14 years early and let the Toxo obsession go- mostly.

Obviously I am a worrier.  The intersection of parenting, science and the media may not be a problem for other people.  They may read an article discussing “new research on Sudden Infant Death Syndrome” dispassionately, soberly waiting until evidence from multiple research studies has accumulated and practical recommendations have been made before they take action.  I wish I was one of those people, but I am not and neither are most other parents I know.  Raising kids can be scary and it’s hard to be rational when you are scared. It’s harder still when the information available to you in the media is often designed to scare you, because it will get your attention and sell their publication.  What is the solution?  I am not sure and I’d love to hear your thoughts.  I am sure it includes parents taking a deep breath and trying to keep things in perspective.  I think that the media needs to be more responsible in how they are reporting health science research.  But I also believe that we need to do a better job of science education in our public schools.  We need to teach students (who are future parents) to be better, more critical, consumers of science.  Yes, I think all students need to understand some basic scientific facts.  But perhaps more importantly, they need to understand the scientific process.  By process I mean the both scientific method and how peer review works.  Even when you have scientific training and understand these processes, it can be hard to make a well-reasoned decision.  But if you don’t understand the process of science, it’s almost impossible.

P.S.  For another interesting perspective on this topic check out this post on the blog Science of Mom.

When N= 1, Reason= 0

Sometimes it’s the little things…

Model of Fruitadens haagarorum at the Dinosaur Journey Museum in Fruita, CO. Photo courtesy of ReBecca Hunt-Foster.

Paleontologist George Callison knew as soon as he found the bones that he had something good.  The new field site, which would eventually be designated the Fruita Paleo Area, was yielding the smaller fossils which could be so hard to find. Dr. Callison had done his doctoral research on snake evolution and hoped to find an early snake species among these tiny fossils.  This find was no snake, but it was exciting. The distal tibia of the tiny leg bone he uncovered was distinctive, and unlike any he had seen before.  Dr. Callison likens it to finding a random car part.  “If you find a spark plug, all you can conclude is that you’ve found something with an internal combustion engine.  But if you find the hood ornament, then you know the make and model of the car you’ve found” says Callison.  These bones were a hood ornament, and they told Callison that he had found something new, a whole new species in fact- the tiny dinosaur that would later be named Fruitadens haagarorum.  

Dr. Callison found the first Fruitadens fossil in 1975, but it would take many years of study before the fossils would be formally described and named Fruitadens in 2009.  Paleontologists now believe Fruitadens was about 26 to 30 inches long and weighed about 1.1 to 1.7 pounds, smaller than your average chicken.  Like a chicken, it probably ate plant material as well as insects and other invertebrates.  Fruitadens walked on two legs like a bird and its front limbs were shortened, making it look vaguely like a miniature Tyrannosaurus rex – but not as fierce.

Fruitadens is not the only species that has been discovered at the Fruita Paleo Area and named for Fruita.  In the late Jurassic period, about 150 million years ago, Fruita was in a floodplain, there were braided stream channels lined with gallery forests, while away from the water the land was relatively dry, much like today.  Fruitadens shared this habitat with other animals like Fruitachampsa. Dubbed “the housecat of the Jurassic” by Dinosaur Journey’s John Foster, Fruitachampsa was related to modern crocodiles, but it was entirely terrestrial and had the size and posture of a cat.   A tiny mammal, named Fruitafossor gobbled termites like an armadillo. With oversized forearms for digging, it earned the nickname:  “Popeye.”  But unlike Popeye or an armadillo, Fruitafossor was tiny– when curled up in a ball, it could fit under a quarter.

Terrestrial crocs and miniature mammals may be very cool, but Fruitadens had an outsized impact on the world of paleontology for such a small creature.  Prior to the discovery of Fruitadens, most paleontologists did not realize that dinosaurs could be tiny.  Small dinosaur fossils were thought to be juvenile specimens of larger species.  But Dr. Callison and his student, Helen Quimby, examined the Fruitadens fossils and realized that the ends of the long bones were fused as they are in adult vertebrates that have finished growing.  Also, the relative sizes of different parts of the bones suggested that they were from an adult.  Callison and Quimby looked at how the bones of birds like turkeys, ostriches and chickens changed as they grew up. (Birds are dinosaurs’ closest living relatives.) When these animals are young, the ends of the limb bones are large relative to their length giving them a “knobby” kneed look.  But the Fruitadens bones had adult proportions.  Based on these two lines of evidence, Callison and Quimby made a convincing case that Fruitadens was a small, but fully grown dinosaur.  This caused paleontologists to go back and look at other small fossils and realize that many of them were indeed tiny dinosaur species – not just young.

Fruitadens is in fact the smallest dinosaur discovered in North America. Now you may be thinking:  “Tiny dinosaur, don’t we call that a lizard?”  But Callison explains that, unlike other reptiles, dinosaurs had a unique hip structure that gave them an erect posture.  Picture how a Tyrannosaurus stands upright like a bird, or how a Triceratops’s belly is raised up off the ground like a cow’s compared to how an alligator’s belly drags on the ground with its legs sprawling out sideways.  This difference in posture also suggests that dinosaurs had a higher activity level than other reptiles, meaning they spent a lot less time sunbathing. So while they are related, dinosaurs are not simply overgrown lizards.

The city of Fruita has rightfully embraced its paleontological prominence.  We have a stylized Apatosaurus on our town logo and Greta the T-rex stands guard in Circle Park.  But perhaps we have embraced the wrong species – those giant dinosaurs get all the glory.  Shouldn’t a small town like Fruita appreciate the little guy?  Shouldn’t a town that celebrates a headless chicken that refused to die also celebrate a tiny dinosaur that dodged 1,500-pound predators like Allosaurus?   Greta the T-rex is here to stay, after all we need someone to protect us from the Grinch at Christmas. But I think that Fruita needs another dinosaur monument:  a tiny Fruitadens– right next to Greta.

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Thanks to Dr. George Callison for teaching me about tiny dinosaurs. Dr. Callison is not only a terrifically interesting scientist, but also a very talented landscape painter. You can check out his work on this website: http://georgecallison.com/.   To learn more about Fruitadens and see a model, visit the Dinosaur Journey Museum here in Fruita, https://www.museumofwesternco.com/visit/dinosaur-journey/ -it’s fantastic.  This post is soon to be published at www.fruitapulp.com, check it out there and learn more about life in Fruita, CO.

Sometimes it’s the little things…