Sunday, December 7, 2008

All that high-flown medical jargon...

Perhaps you are getting tired of all the jargon and eponyms and overly fancy names thrown around in anatomy/physiology. The medical field amazes me with all its jargon and high-flown language... but then again all those terms do sound cool and make you sound smart when you say them. Maybe that is why doctors and nurses like words like diarthrosis, diaphoresis, dyspnea, dysphonia... imagine life without all these fancy terms. It might sound a little like this Mitchell & Webb Show comedy sketch called "Emergency Medical Treatment"... move over ER, House, and Grey's...

For those of you with an iPhone or iPod touch check out the free application called Medical Eponyms, it has tons of terms named after people such as Broca's area or Nissl bodies or my favorite the Sphincter of Oddi. You can also access the database online at

Another great website for those of you with health interests or taking medications is where you can look up the details about most all medications. Most include details related to clinical phramacology such as mechanism of action (if known) as well as pharmacodynamics (what the drug does to the body) and pharmacokinetics (what the body does to the drug). You can enter brand name (e.g., Viagra) or generic names (e.g., sildenafil citrate).


Saturday, November 1, 2008


Don't forget to VOTE on Tuesday NOVEMBER 4th!

It's the American in You...


Thursday, October 30, 2008

Just a shade shy of true wickedness...

What can I say? Halloween makes me think of two things... candy and evil... haha... I heard a song say "I’m just a shade shy of true wickedness" and that made me think about whether we are just a gene shy of true wickedness... in other words is there an "evil gene" that could make humans murderous or overly aggressive or violent. The short answer is no... but there certainly seems to be a tremendous amount of effort attempting to discover a potential genetic basis for social behaviors like aggression or a predisposition to criminal behavior. It is a little scary to think that a monster could be lurking in the human gene pool. But given the complexity of the human behavior and interactions of genes, it seems unlikely that a mutation in a single gene sequence (say adenine to cytosine) during development is going to turn normal humans into serial killers... although it might be a cool movie. During my somewhat futile search for the evil gene I did come across some interesting stuff:
  • In the book Hard-Wired (here), author William Clark points out that in the laboratory, rats and mice have been selectively bred for many generations to create strains that are docile or fearful or aggressive with these traits being passed on to each generation each time they breed.
  • Creating transgenic knockout mice, scientists showed that disrupting a single gene encoding the vassopressin 1B receptor created mice with "reduced levels of social forms of aggression"(here). Genetically introducing a related receptor (vassopressin 1A receptor) into the brain of promiscuous rodents (mating with many partners) transformed them into monogamous (one mating partner), pair-bonding animals (here). Does this mean will will be getting an actual"chill" pill in the future or a monogamy pill for all the cheaters out there? Interesting...
  • A few years ago, scientists created so called "daredevil mice" by altering one single gene that is highly expressed in the amygdala of the brain. These transgenic mice were more fearless and displayed risk taking behavior not normally seen in mice.
  • According to an expert commentary in the Journal of the American Academy of Psychiatry and the Law (here), "any attempt to study violent or deviant behavior under the rubric of evil will be fraught with bias and moralistic judgments. Embracing the term evil as though it were a legitimate scientific concept will contribute to the stigma of mental illness, diminish the credibility of forensic psychiatry, and corrupt forensic treatment efforts." Well okay then... deviant behavior gene.
  • People that carve scary or "evil"pumpkins are 3.5X more likely to commit crimes such as shoplifting, illegal parking, and littering... just kidding. That isn't true. Just my hypothesis.
Take home message? There seems to be no evil gene... maybe we shouldn't even use the term evil in the scientific realm. But certainly, studies of rodents and other species prove overwhelmingly that genes influence social behaviors... and there is likely a cohort or group of genes that influence and/or predispose humans to deviant or bad behaviors. Who knows, someday they might even have a genetic test that will determine if you have an increased risk to commit murder!?

Happy Halloween! Be good.


Wednesday, October 29, 2008

Brain Strain...

If you watch lots of sports like me then you are also hearing injury news about players. Unfortunately, most of the reports are often inaccurate and vague in terms of the anatomy and the actual structures that have been injured. One distinction to keep in mind is sprain versus strain.

According to the National Institute of Arthritis and Musculoskeletal and Skin Disease:

Sprain is a stretch and/or tear of a ligament. One or more ligaments can be injured at the same time. The severity of the injury will depend on the extent of injury (whether a tear is partial or complete) and the number of ligaments involved. Common examples would be an ankle sprain involving the stabilizing ligaments of the ankle or injury to the ligaments of the knee or shoulder.

Strain is an injury to either a muscle or a tendon. Depending on the severity of the injury, a strain may be a simple overstretch of the muscle or tendon, or it can result from a partial or complete tear. Common examples would be the injury of hamstring muscles (biceps femoris, semitendinosus, semimembranosus) or muscle od the back. So injury of the calcaneal tendon (Achilles) would be a strain.

Over at Stephania Bell's ESPN blog she points out that an injury to the acromioclavicular (AC) joint, since it is stabilized by ligaments around the joint, can be called a sprain. Although, injury at the AC joint tends to separate the acromion process of the scapula from its articulation with the clavicle... and so we would often just call the injury a "shoulder" separation. She implies that, perhaps, when the team would like to downplay an injury they might say shoulder sprain rather than the more serious sounding shoulder separation. Recall in class to make the distinction between shoulder separation, at the AC joint, and shoulder dislocation which occurs at the glenohumeral joint (humerus with scapula). Stephania discusses a term called shoulder sublaxation which refers to the humerus slipping only partially off the glenoid surface, but not completely dislocating out of the glenoid fossa... so there is an additional shoulder injury to think about... shoulder sublaxation. You are practically an orthopedic surgeon or physical therapist if you are still reading this... ha!

Go read the super cool anatomical NFL injury blog at ESPN (Click Here).


Friday, October 17, 2008

Hooray for cheap anatomy and physiology textbooks!

I wanted to proudly display my "new" but used and very cheaply purchased A&P textbook... courtesy of by eBay. This was purchased and delivered for under $20... the book is in great shape and hardly looks used at all. The publishing date is 2004, luckily not much has changed in the content of A&P books since 2004 so it would be perfect for any anatomy or physiology class. It did take about a week and a half to arrive but if you are not in a hurry... it even had the CDROM, unopened in the back of the book. This is a great alternative to the $125-$210 new textbooks available online and at the Bookstore.


Tuesday, October 14, 2008

Misty's dancing career and leg go pop!

Superstar athlete and 2-time Olympic beach volleyball gold medalist Misty May-Treanor injured her leg on the reality TV series Dancing With The Stars. She was forced to drop out of the dancing competition and had to undergo surgery to repair her injured leg. During training / rehearsal for the show Misty ruptured her calcaneal (Achilles) tendon. She reportedly heard a "pop" which is common of people tearing their calcaneal tendon... others often describe "feeling" something hit the back of their leg... caused by the sudden rupture of the body's largest and possibly strongest tendon. [Click images for a larger view]

The rupture of the calcaneal tendon could be a somewhat serious injury to a volleyball player like Misty given the tremendous force and stress on the tendon during jumping and leaping. The Achilles is formed by the tendinous contributions of the gastrocnemius and soleus muscles (i.e., the calf muscles) which are used in plantarflexion of the foot at the ankle... which is part of the motion of jumping. Of course, most athletes make a full recovery from this type of injury and the occurrence of re-rupturing the tendon does not appear to be high. Check out eMedicine for a detailed description of Achilles tendon rupture (LINK). Hopefully Misty will be back to volleyball as good as new when she returns to the beach, and perhaps the AVP beach volleyball tour will comeback to Sacramento... haha... probably not... look at the empty stands... regardless, check out May-Treanor's vertical leap at the net. She is going to need those Achilles tendons healed and healthy.


Sunday, October 5, 2008

This is your brain on drugs... errr.... music

All of us would probably agree that the music we listen to depends on our mood or even shapes our mood. A slow song might help you mellow out or fall asleep... loud rock songs or hip-hop might motivate your workout routine at the gym. Songs evoke strong emotions and memories from our past.

But what I really wanted to know is "why does listening to your favorite song make you feel so good?" Like many people, it seems I am always finding a new favorite song, listening to it almost obsessively for awhile, and then eventually it is on to a new one. It occurred to me that this seems a lot like reward-seeking behavior or pleasure-seeking behavior such as eating your favorite food, smoking cigarettes, shopping, taking drugs, hiking to the top of a mountain, gambling, etc. You might wonder, as I did, is music making us feel good just like all these other rewarding stimuli?

Well, it turns out that neuroscientists and psychologists have recently been studying music as a model to discover the brain circuitry involved in pleasure and reward. Here are some interesting things I came across on the subject of music listening, pleasure, and the brain:

  • In humans, music increases activity in a network of brain structures involved in reward and pleasure processing including the nucleus accumbens and the ventral tegmental area (1). These brain structures are also known to be active in response to other very pleasurable stimuli, such as food, sex, and drugs of abuse (2).
  • It is believed that pleasurable music activates dopamine pathways in brain regions such as the nucleus accumbens, thus increasing the levels of dopamine in the brain. Dopamine is a neurotransmitter used by neurons to signal to each other. Interestingly, cocaine exposure increases dopamine levels specifically in the nucleus accumbens of rats (3) and music too has been shown to increase dopamine levels in the rat brain within the nucleus accumbens (4,5). What does all this mean? Drugs and music (both seemingly pleasurable stimuli) induce the same neurochemical changes in the same exact brain regions, at least in rats. This is likely to be similar in the human brain.
  • Increased dopamine levels in the brain are associated with compulsive eating, falling in love, sexual pleasure, drug abuse, alcohol consumption, and many other euphoria-inducing stimuli.
What is the take home message? Well, this just might help explain why listening to music* is one of the most rewarding and pleasurable human experiences. It certainly helps me understand why I like listening to my favorite songs over and over again... it is basically a sonic addiction.

*remember music is cheaper than drugs and healthier than cigarettes. Some free music and dopamine release courtesy of SubPop records. Sorry, no hip-hop :)

1 2 3 4 5 6 7 8 9 10 11

~~~~~ BIO25~~~~~~

Saturday, September 27, 2008

Learn to save a life in 2 minutes... the new CPR

Think watching a two minute video on YouTube might make you a life saver? This video just might... it is on the newest form of CPR for adults that collapse suddenly and it is called continuous chest compression CPR. The physiological basis of this CPR has been discussed in a previous blog post... but check out the video, then go read more about it.

~~~BIO 25/26~~~

Monday, September 22, 2008

TrueBlood?... blood doping and EPO

A recent story in the news reported the re-testing of blood samples from cyclists in this years Tour de France. It seems that several cyclists had suspicious urine samples related to the naturally occurring hormone erythropoietin. In all our bodies, erythropoietin (EPO) is produced by cells in the kidney. EPO circulates in the bloodstream eventually signaling to marrows cells in the cavities of our bones to stimulate production of new red blood cells (erythrocytes). The production of new RBCs is termed... erythropoiesis. Drug companies produce and market synthetic forms of EPO to treat anemia which can often occur with cancer chemotherapy, kidney failure, AIDS, and more.

Cyclists in this years Tour de France are suspected of using a newer generation of EPO called CERA, marketed my the pharmaceutical company Roche. Endurance athletes illegally use EPO type substances in order to increase their RBC count and thus improve the oxygen carrying capacity of their blood. Basically, it improves cardiovascular function giving these elite athletes a potential edge on the competition. Roche suggests that CERA might be more effective than other available EPO drugs... the following is a brief description of CERA from the Roche website:

CERA is a Continuous Erythropoiesis Receptor Activator. Studies have shown that CERA has unique activity at the receptor site. It is postulated this is related to its repeated and rapid attachment and dissociation from the receptor involved in triggering erythropoiesis (red blood cell formation) together with an extended serum half life. This results in more potent stimulation of erythropoiesis, both in magnitude and duration, compared to standard EPO drugs.

~~~~ BIO 25/26 ~~~

Tuesday, September 9, 2008

Smoke 'em if you got 'em... or not

A new report by the American Lung Association describes the current status of tobacco use and policies on college and university campuses in the United States (link to full report). This report has some interesting details... including that 1 in 5 college students smokes cigarettes (or about 19%). Examining the same age group that is NOT in college shows 35% are smokers. The 19% college smokers is the lowest rate in nearly 30 years. Of course, the cigarette industry knows this and is looking to get you on board! Some interesting facts about smoking related to college students:
  • In 2005, the tobacco industry spent more than $1 million per day targeting and marketing cigarettes to college students like you!
  • Cigarette smoking is significantly higher in individuals with lower education levels and lower income levels
  • A recent survey showed that nursing students were more than 4 times as likely to be smokers compared to medical students on the same campus (Ref).
  • In 2005, tobacco companies spent $13.1 billion to market cigarettes. Imagine how much profit they are making in order to spend this much money getting you to buy them!
  • The peak in college smokers seems to have been 1999 with 30% reportedly smoking.
  • Recent declines in college smoking are due partly to the higher prices of cigarettes
  • According to their own documents, tobacco companies market to "occasional smokers" such as college students in order to create new "everyday smokers."
Oh by the way, smoking is still the leading cause of preventable death in the United States, although I believe obesity is catching up. Plus, smoking makes you smell bad... peeeww. Thank you for smoking ;)

---BIO 25---

Monday, September 8, 2008

Ice Cream, You Scream... the science of ice cream

Nothing is more unsettling and disturbing than finding your precious ice cream has been ruined by ice crystals (aka frost bite, freezer burn)... what will I eat for breakfast now? Scientists to the rescue. It appears that scientists (not working on important issues like cancer, AIDS, heart disease, MRSA) have discovered a natural "antifreeze" that can protect ice cream from ice crystal formation in the freezer. The antifreeze substance is actually a naturally occurring protein molecule called gelatin hydrolysate derived from collagen found in connective tissues... related to what is found in Jell-O brand gelatin and ice cream already. This additive appears to reduce or stop ice crystal formation in stored ice cream... which means your ice cream will last forever. Did I mention it is great for breakfast? Read more about antifreeze in ice cream (Click). Some interesting ice cream facts:
  • Ice cream is a $5 billion annual industry in the United States
  • The average American eats 6 gallons of ice cream a year
  • People in the U.S. eat more ice cream than any other country in the world
  • Those tiny hot-dog shaped chocolate sprinkly things are called... JIMMIES after their inventor James Bartholomew
  • Presdient Ronald Reagan declared the third Sunday of July as National Ice Cream Day

--- BIO 25---

Tuesday, April 29, 2008

Drinks 8 Glasses of Water a Day? Myth Busted?

Almost everybody has heard this advice... "Drink at least eight glasses of water a day." Really? I decided that there must be some scientific basis for this recommendation, right? According to a review (2002) by Dartmouth physiologist and medical doctor Heinz Valtin, the advice to consume 8 glasses of water per day (approximately 1.9 liters!) has no apparent basis in the scientific literature. Here is the link to his article in the American Journal of Physiology where he discusses the origins of this advice and whether it is necessary to consume large amounts of water each day.

My interpretation of Dr. Valtin's review is that the average person does not need to gulp down water incessantly all day long. It seems most people end up drinking enough fluid during the day from various beverages including coffee, carbonated drinks and of course water (about 1.5 liters from all sources). So chances are you are already drinking enough water everyday, so perhaps you can stop stressing about it. Of course, if if if you exercise strenuously, work outside, or live in a dry climate then you probably have an increased need for fluid intake.
"... it is hard to imagine that evolutionary development left us with a chronic water deficit that has to be compensated by forcing fluid intake..."
So who or what is behind the popular belief that we are all walking around chronically dehydrated and that we are all in dire need of some cool, clean, and refreshing water? Maybe the bottled water industry has something to do with it? The industry spent $168 million in advertising and made over $11 billion in sales in the United States for 2006-2007 (source). But hey... drink water rather than soda or coffee (its free from the faucet and no calories) but don't panic if you forget the precious water bottle on your way to school. Chances are you won't shrivel up like a prune or ruin your kidneys.


Friday, April 25, 2008

She's Hot + He's Not = Happiness in Marriage

You have seen the celebrity couples and probably know some married folks where the spouses seem equally attractive while sometimes one spouse is clearly better looking than the other... so does this have anything to do with happiness, satisfaction, and success of the marriage? A recent study in the Journal of Family Psychology just might have the answer. The research study is titled "Beyond Initial Attraction: Physical Attractiveness in Newlywed Marriage" and was performed by psychologists from UCLA and the University of Tennessee. Here is an excerpt from the study (PubMED link to article):

Physical appearance plays a crucial role in shaping new relationships, but does it continue to affect established relationships, such as marriage? In the current study, the authors examined how observer ratings of each spouse's facial attractiveness and the difference between those ratings were associated with (a) observations of social support behavior and (b) reports of marital satisfaction. The relative difference between partners' levels of attractiveness appeared to be most important in predicting marital behavior, such that both spouses behaved more positively in relationships in which wives were more attractive than their husbands, but they behaved more negatively in relationships in which husbands were more attractive than their wives.

You might assume from this that, in terms of longterm relationships, physical attractiveness is less important to women while more important to men. One psychologist suggested that when women who are beautiful go out with men who aren't so hot, the men try harder so it makes for a better marriage for both spouses. But remember, this study is not evaluating the importance of physical attraction in dating or initial relationships but rather how relative attractiveness of spouses influences satisfaction and behavior of the couple longterm. This story was reported in the StateHornet as well as many other news sources in the past weeks, including the New York Daily News. Follow the links for some interesting reading.

So, does this mean that women will run out and start dating and marrying men who are less attractive than them? I sure hope so! Haha... but probably not... it turns out scientific research also shows that we are really bad at predicting what will make us happy in life. Psychologists have a term for our brain's inability to accurately predict future happiness... it is called affective forecasting error... but that is a topic for another day.


Tuesday, April 22, 2008

Disturbing trend: Life Expectancy Decreasing for Some in US...

Average life expectancy has steadily increased in the United States over the years. However, there was a steady increase in mortality inequality across portions of the US during the 1980's and 1990's, resulting from stagnation or increase in mortality among the worst-off segment of the population. Female mortality increased in a large number of counties, primarily because of chronic diseases related to smoking, overweight and obesity, and high blood pressure. Here is a link to the recently published research findings, PLoS Medicine.

Analysis of the study from the Public Library of Science:

The findings suggest that beginning in the early 1980s and continuing through 1999 those who were already disadvantaged did not benefit from the gains in life expectancy experienced by the advantaged, and some became even worse off. The study emphasizes how important it is to monitor health inequalities between different groups, in order to ensure that everyone—and not just the well-off—can experience gains in life expectancy. Although the “reversal of fortune” that the researchers found applied to only a minority of the population, the authors argue that their study results are troubling because an oft-stated aim of the US health system is the improvement of the health of “all people, and especially those at greater risk of health disparities”


Tuesday, April 1, 2008

American Heart Association joins the club: new CPR

Continuous chest compression CPR or hands only CPR is now recommended by the American Heart Association for adults that collapse suddenly, presumably due to cardiac arrest. You can read more about this new, simplified version of CPR in the previous blog post on February 9th and also at this "hand only" CPR website. The following are new guidelines from the the American Heart Association Emergency Cardiovascular Care Committee (link to AHA source): [source link]
When an adult suddenly collapses, trained or untrained
bystanders should—at a minimum—activate their community
emergency medical response system (eg, call 911) and
provide high-quality chest compressions by pushing hard and
fast in the center of the chest, minimizing interruptions.

● If a bystander is not trained in CPR, then the bystander
should provide hands-only CPR. The rescuer
should continue hands-only CPR until an automated external
defibrillator arrives and is ready for use or EMS
providers take over care of the victim.

● If a bystander was previously trained in CPR and is
confident in his or her ability to provide rescue breaths
with minimal interruptions in chest compressions, then the
bystander should provide either conventional CPR using a
30:2 compression-to-ventilation ratio or handsonly
CPR. The rescuer should continue CPR until an automated
external defibrillator arrives and is ready for use or EMS
providers take over care of the victim.

● If the bystander was previously trained in CPR but is not
confident in his or her ability to provide conventional CPR
including high-quality chest compressions (ie, compressions
of adequate rate and depth with minimal interruptions)
with rescue breaths, then the bystander should give
hands-only CPR. The rescuer should continue
hands-only CPR until an automated external defibrillator
arrives and is ready for use or EMS providers take over the
care of the victim.


Tuesday, March 25, 2008

Extreme cancer surgery involves temporarily removing digestive organs

Wow, the case of an extreme cancer surgery is currently being reported on the news. The operation removed (only temporarily) several organs and then the organs had to be sutured back in place. The removal was needed to get access to the cancer in the posterior wall of the patient's abdominal cavity. The article stated that the operation was like taking the engine out of a car in order to repair the car while it is still running.
It took seven surgeons more than 15 hours, in which they removed her stomach, pancreas, spleen, liver and large and small intestines, while keeping Zepp (the patient) alive. Once they cut out the tumor, which was wrapped around a major artery, they painstakingly put all the organs back in her body. - ABC NEWS Online
The removal of the tumor was complicated by its location in the abdomen. Reportedly, the small tumor was wrapped around the aorta and the base of the celiac trunk and superior mesenteric artery. Some portions of her blood vessels had to be replaced with artificial vascular grafts made of Gore-Tex (BIO 26 students saw these in lab).

The surgery took advantage of techniques used in organ transplant operations... including cooling and preserving of the patient's digestive organs after removal from the body. The patient was diagnosed with leiomyosarcoma, a somewhat rare form of cancer of the intestines. It reportedly arises from cells in or around the muscularis mucosa. Check out eMedicine for more information on this form of caner (link to eMedicine).


Sunday, March 16, 2008

Love them or hate them... Peeps are here

March brings us two great things... endless hours of college basketball and the endless sugary pleasure of the Peep. I am not sure the relevance of Peeps to physiology or anatomy since they don't have much nutritional value,... we certainly can't measure their forced vital capacity or dissect them to study their fluffy marshmallow interior. Well, perhaps we can use them during a glucose tolerance test to increase blood glucose levels.

One research group has used the Peep as the subject of intense scientific investigation. These scientists studied the health risks of cigarette and alcohol use in Peeps. They concluded:

"The synergistic effect of smoking and alcohol in Peeps produces a rapidly exothermic oxidation reaction, leading to a chemical and morphological divergence from the wild-type Peep phenotypes. Assistant lab members described these divergent Peeps as "less sweet," "crunchier," and "gross" when compared to the Peeps which used either alcohol or tobacco, but not both. For these reasons, it is our strong recommendation to JustBorn Corporation that they supervise young Peeps and educate them of the risks associated with smoking and alcohol."

For further reading on the scientific research on Peeps follow the link courtesy of Emory University scientists and researchers. Peep Research

~~ ~~

Thursday, March 13, 2008

My Pink Spongy Lungs...

Inflated Lungs

The lungs are certainly one of the coolest organs to look at in lab class due to their light, fluffy feeling and their ability to expand to large volumes and quickly recoil... amazing! The above image shows a normal lung before and after inflation. Part of the ability of the lungs to expand and recoil is due to the extracellular matrix of the lung tissue which contains collagen and lots of elastin protein fibers. This gives the lungs their ability to recoil after inhalation so that air is exhaled properly. The videos below show this in action...

Smoking is a health hazard for many reasons such as heart disease and cancer, but smoking also can damage the physical structure of the lung. Cigarette smoking leads to neutrophil activation and retention in the lung tissues. Cigarette smoking induces macrophages to release neutrophil chemotactic factors and elastases, thus unleashing tissue destruction. A number of neutrophil-derived and macrophage-derived enzymes known as proteinases and elastases (ie, proteolytic enzymes) can destroy various components of the extracellular matrix of the lung (e.g., elastin fibers) and cause emphysema (see eMedicine). The tissue integrity of the tiniest airways (like the alveoli and respiratory bronchioles) is destroyed over time and normal elasticity is lost. There is also destruction of the aveolar capillaries which impairs gas exchange in the lung. All of this reduces the ability of the lungs to function and this is especially noticeable when patients with emphysema are asked to expire after maximal inhalation. It takes them longer to expire air out of their lungs since exhalation requires the inherent elasticity of the lung tissues, which they have lost with emphysema.


Thursday, February 28, 2008

Will Ferrell is Good For Your Arteries.

Well, assuming you find Will to be funny then watching his movies just might improve the functional responses of your arteries. You might have heard "laughter is the best medicine" or maybe even that laughing is good for your heart. But is there any truth to this? The journal Heart (formerly the British Heart Journal) published a scientific letter titled "Impact of cinematic viewing on endothelial function" in 2006 that just might have the answer (link to abstract). Heart 2006;92:261–262

These authors studied the blood flow responses in the arteries of the arm in subjects before and after they watched movies. They compared the vascular responses of individuals that watched movies evoking mental stress (e.g., Saving Private Ryan) versus individuals watching movies evoking laughter (e.g., There's Something About Mary).

They found movies that made you laugh improved endothelial-dependent blood vessel dilation (see the figure below)... this is a fancy way of saying that the arteries and arterioles dilated more in response to a stimulus and thus improved blood flow. The laughter group had improved arterial vasoldilation compared to baseline while the mental stress group actually had impaired vasodilation compared to baseline. They tested this using reactive hyperemia which A&P students remember from lab. Reactive hyperemia is a transient increase in blood flow to an organ or tissues after a period of ischemia or arterial occlusion. Basically, the authors occluded blood flow to the arm for five minutes (ouch) and then released the occlusion. They used ultrasound imaging to capture the diameter changes in the brachial artery during the experiments to assess the functional responses during hyperemia. In class, we merely looked at the redness in the skin to assess the extent of hyperemia (see our class images). In the movie experiments, during hyperemia, brachial arteries dilated to a greater extent in the arms of laughter viewers. By the way, the reason it is called "endothelial-dependent" is because the endothelial cells are important in generating the signals that contribute to the blood flow changes. The mechanisms explaining the findings of this study are unknown but the authors did speculate that nitric oxide (NO) signaling could be involved. You might remember that NO produced by cells, like endothelial cells, can cause smooth muscle relaxation and thus improve blood flow.

Conclusion: go see funny movies and not stressful or scary ones! Superbad, not super scary... after all, it is good for the function of your arteries.

Heart 2006;92:261–262


Tuesday, February 19, 2008

Eat your heart out...

You don't often get to see an anatomically correct-extra-credit-chocolate-human heart cake... but alas you will today. I am not easily impressed but this cake looked great and the myocardium has never tasted better! Actually, I think I see the left circumflex artery too. Enjoy. [Link to Full Size Cake Heart]

cake heart diagram labeled

Courtesy of Jaclyn.



Thursday, February 14, 2008

♥ ♥ What's in a Kiss? Science of Kissing ♥ ♥

With Valentine's Day upon us, it is not surprising to see web articles about kissing... how to kiss, how not to kiss, best movie kisses, best lips (btw, who is the owner of the famous lips in the pic over there--->). What about the science of kissing? Why do we kiss? Is there a biological basis of kissing? A recent article at Scientific American has all the answers... well, a few answers and it is all free and available if you follow this link. You should check it out but here are some tidbits that I found particularly interesting:
  • Kissing may have evolved from primate mothers’ practice of chewing food for their young and then feeding them mouth-to-mouth.
  • Osculation is the fancy, scientific term for kissing... as in "I don't osculate on the first date."
  • Up to 10% of the human population does not kiss, that is over 650 million people... I assume that is a cultural thing?
  • Some scientists theorize that kissing is crucial to the evolutionary process of mate selection. Bad kisser = bad genes? Sort of a litmus test for mates.
  • The process of kissing utilizes five of the 12 cranial nerves to transmit signals to and from those lips... can you name them? See the end of this blog post. I am trying to remember them all.
An interesting issue that caught my attention is the idea of the kiss as an important factor in mate selection (i.e., the litmus test). Does a kiss provide more information about compatibility then we consciously realize? Everybody says how important the first kiss is, right? Perhaps a couple's "kissing compatibility" signals some sort of primal or fundamental fit between potential mates.... or... maybe it is just kissing. Who knows.

One thing not discussed in the article is the origin of lips... there must be some anthropologist studying this stuff... lip morphology? Was a certain type of lip selected for during evolution through mate selection? We might assume nowadays that bright, full lips were probably attractive to mates but is that really true of our ancestors? Is there any biological significance or advantage of full versus thin lips other than mate selection? Have lips changed dramatically since our more ancient, primitive ancestors? Maybe ask your physical anthropology professor. PS- Everything you wanted to know about Lip Anatomy and more courtesy of two different articles at eMedicine. [Link1] and [Link2]

Answer for 5 Cranial nerves used in kissing: Trigeminal V (sensory touch for tongue and lips); Facial VII (muscles to move lips); Hypoglossal XII (muscle to move tongue); Facial VII and Glossopharyngeal IX (taste sensation from the tongue); hmmm they say 5 of the 12 so perhaps they include Olfactory I (smelling while you kiss).


Monday, February 11, 2008

Panthers, Pucks, Skates, Carotid Arteries... Huh?

Florida Panthers forward Richard Zednik survived a potentially deadly gash to the neck that partially severed his right common carotid artery (Associated Press link). During the hockey action his teammate fell directly in front of him and the teammate's skate came up to neck level slicing directly into Zednik's right neck. In video of the incident, blood can be seen spraying the ice below Zednik as he falls grasping his neck. He quickly got up and skated to the bench, holding his neck. He was rapidly helped from the ice and later underwent emergency surgery to repair his right carotid artery which doctors indicated was hanging on by only a small thread of tissue. His right external and internal jugular veins were not damaged. As of writing, he was in stable condition in the hospital. He seems very lucky! Doctors say he lost approximately 5 units of blood... that is a bit more than 2 liters. Imagine a 2-liter bottle's worth of bood spilling out of your body. During the surgical repair, the right carotid was clamped for several minutes which would seemingly reduce blood flow to the brain. His doctors said he did not seem to have any brain injury or brain damage due to the interrupted carotid blood supply. Of course A&P students know the left common carotid and vertebral arteries also carry blood to the brain.

There is video of the incident on YouTube if you want to see it for yourself (YouTube link).

A great video for physiology / anatomy students is the medical press conference with the Buffalo Sabres team physician and the emergency surgeons that helped save Zednik... linked here (Buffalo General Hospital). Watch this as it has a terrific discussion of the anatomy of Zednik's injury. Interestingly, the team physician mentions that this injury was not like a previous NHL injury to the neck of goalie Clint Malarchuk which severed his jugular vein. The jugular is a low pressure vein carrying blood away from the head while the carotid is a high pressure artery carrying blood to the head. Large artery injuries are always very dangerous due to the threat of rapid blood loss which could severely reduce blood pressure, causing loss of consciousness and eventually death. As the angiogram below shows, the carotid arteries are large and are located close to the aortic arch and the heart itself... thus a severed carotid artery is serious business and Zednik is lucky to be alive.


Saturday, February 9, 2008

This is not your parents' CPR: continuous-chest–compression CPR

CPR (cardiopulmonary resuscitation) without mouth-to-mouth rescue breathing? It is called continuous chest compression CPR or compression only CPR and requires no rescue breaths. Several studies suggest that continuous chest compression CPR for adults that collapse suddenly presumably due to cardiac arrest is just as good as standard CPR or possibly even better. Okay, perhaps you are thinking... no way! What about 15:2 or the newer 30:2 compressions to breaths I learned in CPR class?

Researchers from Seattle, Tucson, and Japan have shown that bystander CPR is equally effective or better when performed with chest compressions alone compared to standard CPR with alternating compressions and rescue breaths. Why would this be? Isn't the point of CPR to breath for the person and to circulate their blood by compressing the chest? Right... but the blood is well oxygenated when somebody suddenly collapses from cardiac arrest (i.e., heart stops pumping). Thus, rescue breaths are not really necessary to get oxygen into the blood... rather chest compressions are most important to get needed blood flowing to the brain and heart's myocardium. In fact, delaying the compressions in order to perform breathing might actually reduce the effectiveness of CPR. The technical details are reviewed in Circulation by Dr. Gordon Ewy of the University of Arizona Sarver Heart Center. It seems the oxygenated blood in the body can support the heart and brain for several minutes as long as it is circulated adequately via chest compressions.

Some communities are already teaching continuous chest compression CPR... some have called this new CPR "Call and Pump" referring to the need to call 911 and then begin 100 chest compressions per minute until "the patient or paramedics tell you to stop" or until you can't continue. A very short and detailed tutorial on continuous chest compression CPR is published in Circulation. Go read it! This type of CPR is not recommended in children or when respiratory arrest is suspected such as drowning, drug/alcohol overdose, choking, severe asthma or carbon monoxide poisoning... in these cases CPR with mouth-to-mouth breathing is needed to help oxygenate the blood since the primary problem is not the heart but a lack of oxygen (i.e., suffocation) that eventually leads to cardiac arrest.

A study published in Nov. 2007 (Circulation) used a swine (pig) model of out-of-hospital cardiac arrest with bystander CPR to compare continuous chest compression (CCC) CPR with standard 30:2 compression to breaths CPR. Animals in cardiac arrest for varying amounts of time (3-6 minutes) due to ventricular fibrillation then underwent either CCC or Standard CPR. After 12 total minutes of fibrillation (cardiac arrest), defibrillation was performed using advanced cardiac life support standard guidelines. In essence, this study simulated a collapse, followed by some delay to the start of bystander CPR followed by later arrival of medics that initiated defibrillation. Then 24-hr after the resuscitation, survival and neurological state were evaluated. Neurologically normal survival at 24 hours after resuscitation was observed in 23 of 33 (70%) of the animals in the continuous chest compression group compared with only 13 of 31 (42%) in the standard 30:2 CPR group. Thus, CCC CPR improved survival with normal neurological function compared with standard CPR. Of course, this is an animal study and not humans. Nevertheless, the results are compelling and suggest that mouth-to-mouth might not be needed and could even be detrimental in the case of sudden cardiac arrest. Why? The idea is that the continuous compressions increase cerebral and coronary blood flow and thus improve survival. Interruptions in chest compressions required for rescue breathing reduce perfusion to the heart and brain which could explain the reduced survival and neurological outcomes with 30:2 CPR in this animal study.

The key potential benefit of compression only CPR is the idea that more bystanders would initiate and perform CPR if it is simple to remember and it does not require mouth-to-mouth contact.

This recent research might be changing the way you learn bystander CPR in the near future... well probably not until 2010 when the American Heart Association will review and revise CPR guidelines. But CPR can be easy and the key is to do it!

Finally, CPR helps save lives but ultimately defibrillation (shocking) of the heart is needed for the patient to recover from cardiac arrest. The faster this happens the better. Automated external defibrillators (AEDs) are becoming common place in gyms, malls, and airplanes. The faster bystanders or medics can shock the heart back into rhythm then the better the survival rate for the subject. Interestingly, after about 5 minutes of cardiac arrest, performing compressions immediately before and after the defibrillator shock appears to help survival rates. IN 1999 a study by the University of Washington and Seattle Fire Dept showed improved survival if medics performed 90 seconds of CPR immediately before automated external defibrillation was attempted (JAMA link). Basically, if the subject had been collapsed for 4-5 minutes or longer then CPR (with the goal of 150 compressions in 90 seconds) prior to any attempt to shock the heart actually improved survival. In a Norwegian study, 3 minutes of standard CPR was performed by arriving emergency personnel prior to attempts to shock the heart compared with immediate attempts to shock the heart (JAMA link). Overall, no difference in survival rates was observed until researchers examined the survival of subjects with ambulance arrival times greater than 5 minutes after collapse. In these subjects, 3 minutes of CPR prior to defibrillation significantly improved survival to hospital discharge (22% in the CPR first group versus 4% in the immediate defibrillation group). See figure below.


Thursday, January 31, 2008

Got Blood?

A company in the US is using enzymes to convert blood cells with differing blood types (A, B, AB) to type O. This eliminates surface markers (i.e., antigens) on the red blood cells that can trigger an immune response when donor blood is transfused into a recipient. The company called ZymeQuest uses methods involving two enzymes from different bacteria to enzymatically remove the carbohydrate surface markers. This essentially makes any blood cell into type O which refers to the lack of A and B surface markers. Why is this important? Type O blood cells can be transfused into a person with any of the ABO blood types (A, B, AB, or O)... so having more type O blood would seemingly increase supplies of blood compatible with more people. Read more about ZymeQuest and their red blood cell conversion here.

A&P students might wonder, what about the Rh (D) antigen or surface marker? When the Rh antigen is present on red blood cells then the person's blood type is called "positive"... for example, red blood cells with the A antigen and Rh antigen are blood type A+ or A-positive. ZymeQuest doesn't seem to have found an enzyme to cleave off the Rh antigen. Ideally, the enzymatic conversion would strip both the A and B antigens as well as the Rh antigen, thus making treated blood a nearly universal donor supply... i.e., able to be donated into any blood type recipient. Remember, type O- or O-negative blood is considered the universal donor since these RBCs lack the A, B, and Rh surface antigens/markers.

What is the big deal? What happens to me if I get transfused with the wrong blood type? The short answer is that it depends, you could get mildly sick or in extreme cases you would die. eMedicine (topic: transfusion reactions) has the technical answers to this question:

Acute hemolytic transfusion that are immune-mediated (i.e., giving somebody the wrong blood type that reacts with antibodies in their plasma)

Immune-mediated hemolytic transfusion reactions caused by immunoglobulin M (IgM) anti-A, anti-B, or anti-A,B typically result in severe, potentially fatal intravascular hemolysis - so yes people can die from getting the wrong ABO blood type. Immune-mediated hemolytic reactions caused by immunoglobulin G (IgG), Rh (D) or other non-ABO antibodies typically result in shortened survival of transfused red cells, and relatively mild clinical reactions.

Acute hemolytic, immune mediated
: Most severe and fatal reactions result from inadvertent transfusion of group AB or group A red cells to a group O recipient. Renal failure and intravascular coagulation are potential complications for patients who survive the initial acute reaction. Fatal cases are 1 case per 250,000-600,000 so it seems rare.

It pays to be a baby... Because newborns do not form naturally occurring antibodies to ABO blood group antigens during the first few months of life, acute ABO-related transfusion reactions are not observed in this age group.