Tuesday, December 28, 2010
Friday, December 17, 2010
To be clear, I should start by telling you that I’ve never much cared for meat. I deleted it from the menu at age 19 and was completely unfazed by the change. Prior to that I’d favored meat products that were so chopped, burnt and salted that their original source could scarcely be detected. I don’t find steak delicious or barbeque irresistible. I have never wistfully looked at friends eating hamburgers and thought, “Sigh, that could be me.” These days I eat fish from time to time and enjoy it, but if society outlawed the consumption of sea creatures, I doubt I would spend much time mourning the loss. In short, the question of whether or not scientists will be able to produce in vitro meat is not really my problem. I won’t be eating it either way.
Many of my fellow humans don’t share my preferences. People around the world can’t seem to get enough meat, and the growing demand for it threatens not only the health of the consumers and the quality of life of the consumed, but also the planet we all occupy. (So I guess this subject may affect me after all, beyond just the level of scientific curiosity.) The inefficiency of meat production is no secret. 70% of agricultural land is allotted to livestock farming, mostly to supply food for these animals. More than double the amount of water and energy is required to support a meat-eating diet than a vegetarian one. How do we go about fixing this issue? Some think the answer lies in finding a way to grow meat without growing animals.
In vitro meat is real muscle tissue grown from stem cells of animals.* While being able to grow a steak in a Petri dish would theoretically eliminate many of the problems of traditional meat production, it is (as with many laboratory endeavors) more complicated than it might initially sound. Scientists in the Netherlands had been dutifully working toward assembling the world’s first in vitro sausage, but came up with only about a tenth of the material needed when their funding ran out last year. The logistics of lab-grown meat are complicated, especially with the ultimate goal being the ability to grow meat on a large enough scale to meet the demands of a carnivorous populace. For one thing, an animal-free growth medium must be found. Regular cell-culture medium is made from fetal calf serum and thus using it would require, well, cows. This hardly solves the problem of maintaining livestock. So far the best contender is a medium made from maitake mushrooms. Additionally, just letting stem cells proliferate yields a limp, texture-less product. The lab-grown tissue needs exercise to resemble that from live animals. This can be accomplished by regularly administering an electrical current to the growing cells. But of course this process requires electricity, not to mention that it would likely fuel the “Frankenfoods” name-calling that will inevitably greet in vitro meat at its grand debut.
Despite these hurdles, some victories have already been reported. In 2002, scientists successfully grew goldfish fillets in a laboratory using whole muscle biopsy pieces rather than isolated stem cells. The samples grew between 13% and 79% (depending on the type of culture medium used), which makes the experiment sound more like meat amplification than the creation of in vitro meat. It’s sort of like the Bible story about the loaves and fishes, except in this version Jesus dons a lab coat, cuts the fish into small slices, centrifuges the slices into pellets and lets them sit in growth medium for week. Amen. After growing the fillets, the team marinated them in lemon, pepper, garlic and olive oil and fried them (I am not making this up, it’s in the Methods and Material section of their article) and presented them to a panel to be viewed and smelled, though not tasted.† The observers concluded that the product appeared to be edible. Not bad, considering that people aren’t exactly queuing up to eat goldfish from any source.
Taste and public willingness to ingest such a new and novel form of meat are potentially bigger stumbling blocks than any of the technical problems that have thus far arisen. Lab-grown meat is doomed to be perceived as “unnatural”. At this stage, scientists are mostly working on making an in vitro version of processed meat. Because the muscle can only be grown to a limited thickness without creating some sort of artificial vascular structure, steaks are still very far from being realized. The current goal is to make enough thin strips to grind up, flavor and assemble into something like a sausage or a patty. It doesn’t sound especially appetizing. However, consider what consumers already tolerate (not always knowingly) in processed meat made from real animals. Let’s examine how natural the common hamburger is.
Once upon a time, ground beef was made by taking a piece of beef and putting it through a meat grinder. Simple enough. And while the best cuts of beef may not have been selected for this honor, it was at least a single piece of meat from a single cow. With the rise of factory farming and the push for more and cheaper meat, things have gotten a bit messier. A package of ground beef purchased from a modern supermarket is a grim potpourri of meat products from multiple cows, slaughter houses, cities and countries. Much of the meat used in ground beef is what is referred to as “fatty trimmings”. These are parts cut off from higher-grade meat. They come from sections of the animal that are the most susceptible to E. coli contamination. In order to offer the consumer a lower-fat ground beef (something more comparable to what could be made by grinding whole cuts of high-grade meat) these trimmings can be mixed with processed “texturized beef product”, a substance made by centrifuging fatty trimmings. (Look! A centrifuge, just like in the lab.) About a decade ago, an innovation made it possible to sell trimming that would previously have been usable only in pet food, due to their high bacterial content. This ingenious method involved simply adding ammonia to the product to kill bacteria. Ammonia, in case you’ve forgotten, is the chemical you use to clean your toilet. Miraculously, the FDA approved this as safe and, since ammonia is considered a “processing agent”, it needn’t even appear on the ingredients of processed beef.‡
The lab-grown meat is starting to sound pretty tasty, isn’t it? If nothing else, it’s at least free of E. coli. Real animals have digestive systems that house this bacteria. Muscle grown in a Petri dish doesn’t generate solid waste, thus eliminating the problem of elimination. But if bad PR doesn’t thwart in vitro meat, cost likely will. So far the research is expensive and there is no solid plan for making the product cheaper than the already rock-bottom (in price and quality) meat pastiches of our modern world. The obvious question is whether creating meat that is kinder to the environment and to animals is even the right approach. Given all the possible hindrances, it might actually be easier convince society to reduce its meat consumption. I wouldn’t expect meat enthusiasts to give up the product entirely, but the low quality of the meat being consumed says something about its erroneously-perceived necessity. Are people really so desperate to consume this substance that they’re willing to buy beef soaked in toilet cleaner? Maybe meat should be an occasional splurge rather than a daily dietary requirement. Much of the scary processed beef I described in this article is sold to cash-strapped public schools that need to cut back on the cost of their lunch programs. Why not just go the extra step and not buy meat at all?
As for which is more sick and wrong, in vitro meat or regular processed meat, it’s up for debate. One of the more creative objections to lab-grown meat I encountered while researching this article was the possibility of cannibalism. If one can grow muscle tissue from pig or cow explants without killing the animals, one could also grow human meat. In fact, there’s no reason a person couldn’t grow meat from tissue samples from their own body. Given the bizarre items that adventurous gourmands will go out of their way to eat, lab-grown human flesh doesn’t seem out of the question.§ But there is no need to address these ethical concerns yet. We’ve yet to even finish that lab sausage. It’s just food for thought. Bon appetite.
* Thus far this has been done using adult stems cells, which have already differentiated into a specific tissue type (in this case muscle). Unlike the pluripotent embryonic stem cells you hear about in the news, adult stem cells are not immortal. They have a finite number of cell divisions in them before they expire.
† Society is still somewhat unclear as to whether or not it is legal to eat what is still an experimental product. If anyone gave in to curiosity and took a bite of the fried goldfish before feeding it to the trash, they wouldn’t be encouraged to disclose their observations to us.
‡ The punch line to this story is that, following complaints about the nasty smell and taste of ammonia, the processors reduced the amount of the chemical being added to levels that may not be sufficient to kill bacteria. So there is now simultaneously too much and not enough ammonia in America’s hamburgers.
§ Cheese fermented by live maggots (Casu Frazigu), coffee made from beans ingested and excreted by exotic mammals (Kopi Luwak), deliberately rotten eggs (“century egg”). The list goes on.
Who told you this?
Jones, N. 2010. “A Taste of Things to Come?” Nature 468: 752-753.
Marloes, L.P. et al. 2010. “Meet the New Meat: Tissue Engineered Skeletal Muscle.” Trends in Food Science & Technology 21: 59-66.
Benjaminson, M.A. et al. 2002. “In Vitro Edible Muscle Protein Production System (MPPS): Stage 1, Fish.” Acta Astronautica 51: 879-889.
Hopkins, P.D. and Dacey, A. 2008. “Vegetarian Meat: Could Technology Save Animals and Satisfy Meat Eaters.” Journal of Agricultural and Environmental Ethics 21: 579-596.
Moss, M. “The Burger That Shattered Her Life.” The New York Times. October 3, 2009.
Moss, M. “Safety of Beef Processing Method is Questioned.” The New York Times. December 30, 2009.
Friday, December 10, 2010
|Thermophiles add brilliant colors to a hot spring at Yellowstone National Park, while psychrophiles can turn ice red. How cool is that?|
Wednesday, December 1, 2010
Wednesday, November 24, 2010
Friday, November 12, 2010
Monday, November 1, 2010
Thursday, October 28, 2010
Friday, October 22, 2010
Saturday, October 16, 2010
For the latter half of October I have opted to do undertake (pun intended) a 3-part series on scary sleep disorders. If all goes as scheduled, I shall deliver the final installment of this terrifying trilogy just in time for Halloweekend. And now, we begin our journey into darkness with a topic that is sure to keep you up all night…
Humans divide their time between 3 main conscious states. Wakefulness, slow-wave non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM).* Generally these states are experienced sequentially, and all is well. However, the absence or mixing of any of the states can be disorienting, debilitating and even deadly
Insomnia is the most frequently reported sleep disorder in the general population. It is defined as the inability to obtain enough sleep in order to feel rested, which can mean insufficient quantity or quality of sleep, or both. Its causes are diverse, ranging from physical problems such as obstructive sleep apnea † and restless leg syndrome‡ to social and psychological ones like night shift work and anxiety. Sometimes there is no traceable cause. As a lifelong poor sleeper, insomnia is a familiar experience that I would describe as frustrating to maddening, depending on severity. I was, however, surprised to learn that the condition could also be completely incapacitating and ultimately lethal. Such is the fate of those afflicted with fatal familial insomnia (FFI), a genetic disease as disturbing as it is rare.
FFI is, in fact, extremely rare. So much so that the mere diagnosis of a new case is often deemed worthy of its own journal article. The conditional was first described in a 1986 New England Journal of Medicine article and is believed to affect only about 40 families in the world today. It is a prion disease with autosomal dominant inheritance.§ This means that it requires only one gene with the disease-causing mutation from either parent. As with other lethal dominantly-inherited diseases, such as Huntingtons, FFI was able to persist because its symptoms generally do not manifest until after childbearing age. A parent who carries the problematic gene has a 50% chance of passing it on to any one of his or her children, but may appear to be in perfect health until things go dreadfully awry somewhere in middle to late adulthood.
Prion diseases cause degeneration within the central nervous system. FFI does its damage to the thalamus, a region of the brain that is involved, among other things, with the regulation of sleep and wakefulness. The clinical presentation of FFI begins with a progressive inability to sleep. Patients may also exhibit weight loss, difficulties with focus and memory, loss of coordination of muscles and muscle twitching. Gradually they become completely incapable of achieving slow-wave or REM sleep. During this process another curious set of symptom appears – hallucinations and the enactment of dreams during wakefulness. It is as though the dreams normally experienced during REM sleep begin to intrude into the waking state. Patients live in a gloomy, clouded limbo, neither fully asleep nor fully awake. Eventually coma and death arrive to turn off the lights. The course of this entire nightmare varies from about 8 month to 2 years. It is a long time to go without a good night’s sleep.
The name fatal familial insomnia may be a bit misleading, as it implies that its victims actually die from insomnia. Since the inability to sleep present in FFI is caused by the destruction of the thalamus, insomnia could just as easily be viewed as another byproduct of the disease. A symptom rather than a cause. It’s one of those tricky chicken-or-the-egg questions. Scientists are pretty good at designing experiments in which animals drop dead after being forcibly kept awake for weeks, but they have a harder time determining what exactly killed them. Examinations of the animals after they die tend to turn up healthy organs and no clear signs as to what physically went wrong. Sleep is a nebulous field. There is little debate that we need it, but no solid proof as to why we need it. So cherish the sleep that you can fit in to your busy schedule, lest it be brutally taken from you by a rare genetic illness.**
* REM sleep is the stage in which dreaming occurs. During REM sleep the brain is active but the body’s voluntary muscles are paralyzed, theoretically to protect the sleeper from acting out dreams.
† Obstructive sleep apnea is the blocking of airways during sleep, which leads to multiple brief awakenings during the night to obtain more air (up to 100 per hour of sleep). Sufferers may not even realize that they are losing sleep at night as they will not recall these episodes and experience their symptoms mostly in the form of daytime sleepiness. The condition also causes snoring.
‡ Restless leg syndrome was recently mocked (by me) in another article. It is a real malady, it is just not as prevalent as the pharmaceutical industry would have you believe. It is characterized by uncomfortable creepy-crawling feelings in the legs and a subsequent urge to move them. These symptoms worsen during inactive periods, for example – lying down and attempting to go to sleep.
§ A prion is a mis-folded protein that replicates itself using healthy cells, not unlike a virus. You have likely read about prions before, as they are also the culprit behind bovine spongiform encephalopathy, aka mad cow disease.
** There is no actual causal relationship between these two things. I’m just being dramatic. It’s October.
Who told you this?
Mahowald, M.W. and Schenck, C.H. 2005. “Insight From Studying Human Sleep Disorders.” Nature 437: 1279-1285.
Raggi, A. et al. 2008. “The behavioral features of fatal familial insomnia: A new Italian case with pathological verification.” Sleep Medicine 10: 581-585.
Krasnianski, A. et al. 2008. “Fatal Familial Insomnia: Clinical Features and Early Identification.” Annals of Neurology 63: 658-661.
Gallassi, R. et al. 1996. “Fatal familial insomnia: Behavioral and cognitive features.” Neurology 46: 935-939.
Medori, R. et al. 1992. “Fatal familial insomnia: A prion disease with a mutation at codon 178 of the prion protein gene.” The New England Journal of Medicine 326: 444-449.
Special thanks to Elizabeth, who first alerted me to the existence of this ailment during an evening of dancing and karaoke.
Friday, October 8, 2010
CPR stands for Cardiopulmonary Resuscitation. That means the heart and lungs are the organs of focus. The target audience for CPR is anyone experiencing cardiac arrest outside of a hospital setting. In cardiac arrest the heart stops circulating blood (and thus oxygen), causing the victim’s breathing to be impaired. This is the problem that performing CPR is aiming to fix. CPR does not address realigning dislocated shoulders, sucking venom out snake bites, escaping a burning building and countless other first-aid and wilderness-survival emergencies. You’ll need to go elsewhere to acquire those skills. However, CPR is potentially life saving to those for whom regular heartbeat and breathing have suddenly ceased.
CPR training got an overhaul in 2005. In the late 1990’s The American Heart Association (AHA) commissioned a reevaluation of existing guidelines for providing CPR, and the new guidelines were based on these findings. The biggest changes were made to how laypeople are taught to do CPR. In the past, we would have been given instructions similar to those designed for healthcare providers. However, things have been significantly dumbed down for our frail civilian brains. The reasons for this can be distilled to the observation that laypeople often forgot the intricacies of their training soon after obtaining it and then, when faced with an emergency, worried about screwing up. They lost valuable time fretting over making things worse when almost anything would have been better than nothing. With this in mind, the 2005 AHA guidelines dropped distinctions in the chest compression-to-ventilation ratio for different ages (sizes) of people. Every man, woman, child and infant now receives cycles of 30 chest compression and 2 breaths. You’re just told not to press as hard on the smaller humans (2 hands for an adult, 1 hand for a child, 2 fingers for a baby).
Another innovation by omission is that laypeople are no longer instructed to take the pulse of the suspected victim of cardiac arrest. We are only to check for breathing. No breathing = CPR. Why? Apparently we were being really slow about it. Locating a pulse is harder than it looks, and this was found to delay the initiation of CPR. With CPR, sooner is better than later.
And something is better than nothing. The rescue breathing is optional. If for whatever reason you do not feel comfortable blowing into a stranger’s mouth, the AHA says to just go ahead and do the chest compressions. There’s been much talk lately that switching to a “hands-only” protocol in general might be beneficial. The logic behind this echoes the above-mentioned concerns about bystanders being more likely to rapidly initiate CPR if it is made as uncomplicated as possible. Just press on the person’s chest in a rhythm similar to a normal heartbeat†. Also noted was that the ick-factor of the breathing might deter more germ-phobic would-be-rescuers.
A number of studies have examined this, 2 of which were recently published in the New England Journal of Medicine. Both studies were conducted by having emergency dispatchers deliver randomized different sets of instructions to callers reporting cardiac arrest emergencies: some were instructed to provide chest compression and breaths, the others chest compression only. ‡ What the authors found was the while recipients of the hands-only CPR did not fare significantly better than those who received the traditional sets of compressions and breaths, they certainly didn’t fare worse. Additionally, in one of the studies, those whose cardiac arrests had cardiac causes (as opposed to non-cardiac causes such as drug overdose) tended toward better outcomes when given just chest compressions and no breaths. It can be argued that, since at the time of a sudden cardiac arrest the body still has a decent volume of oxygen available (roughly 10 minutes worth), rescue breathing is not as important in the first few minutes and it is best to minimize interrupting chest compressions, other than to reassess breathing.
There has yet to be a consensus as to which version of CPR is best. Our class taught the chest compressions and rescue breathing version, although at least 2 members of our small class (myself and the lady who posed the question) were already aware of the debate.
I had a number of other questions for our instructor. What if the unconscious person might have choked on something (as small children are prone to do)? Answer: still perform CPR, it won’t make anything worse and might help. Can I get sued for doing this? Answer: in America, anyone can get sued for anything, but such cases are generally dismissed.
Had I consulted with others prior to attending the class, I would also have inquired if, once I got my CPR certification card, I could get sued for not performing CPR. One friend claimed to have been told something to that effect during his CPR certification, but I have yet to find any confirmation of this. Either way, I will gladly administer chest compressions to any of you who have heart attacks in my presence. Although I can’t make any promises about doing the rescue breathing.
* For our purposes here, a layperson is anyone who is not a healthcare provider, regardless of how brilliantly you did on your college biology exams.
† The EMS guy who taught our CPR class informed us that the song “Stayin’ Alive” has a suitably paced beat to it, so you can always hum the Bee Gees to yourself if you’re unsure of what a normal heart rate feels like.
‡ If you’re thinking that it sounds like people were participating in these studies without consenting, you’re absolutely correct. However, the authors assure us that ethics committees and “appropriate review boards” signed off on their methods. If it makes you feel any better, surviving participants of one of the studies were eventually informed of their contribution to science. And now you’re probably thinking, “What about the friends and families of the non-survivors?” and I just don’t have an answer for you. I’m guessing no?
Who told you this?
2005. “Overview of CPR.” Circulation 112: IV-12-IV-18.
Sayre, M.R. et al. 2008. “Hands-Only (Compression-Only) Cardiopulmonary Resuscitation: A Call to Action for Bystander Response to Adults Who Experience Out-of-Hospital Sudden Cardiac Arrest.” Circulation 117: 2162-2167.
Weisfeldt, M.L. 2010. “In CPR, Less May Be Better.” New England Journal of Medicine 363: 481-483.
Rea, T.D. et al. 2010. “CPR with Chest Compression Alone or with Rescue Breathing.” New England Journal of Medicine 363: 423-433.
Svensson, L. et al. 2010. “Compression-Only or Standard CPR in Out-of-Hospital Cardiac Arrest.” New England Journal of Medicine 363: 434-442.
Helpful and patient CPR instructor whose name I forgot.