BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: heart

Circulation: The Fight Against Gravity

How the human body is truly remarkable

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Can Too Much Sitting Affect The Shape Of Your Heart?

A new research article shows that the heart, besides humans’ joints and tendons, is also optimized for endurance. But, this depends on how active the person is. To conduct this study, scientist gathered 160 adult males from four different groups: football linemen, long-distance runners, inactive adults, and Native American farmers celebrated for their running ability, known as the Tarahumara. Scientist also looked at the hearts of 43 adult male chimpanzees for comparison. 

To examine the heart of these groups, scientist used an ultrasound. When examining the hearts of the four groups, researchers reported in the Proceedings of the National Academy of Sciences that there were noticeable differences in the left ventricle-the thickest of the heart’s four chambers-where blood is pumped. The long-distance runners and Tarahumara farmers had long ventricles with thin walls. This helps to pump large volumes of blood for a long period of time. The inactive adults and the football linemen, who are trained for short, high-intensity exercise, had wider ventricles with thick walls. The same shape was found in the chimpanzees who participate in short, high-intensity exercises like climbing and fighting. They had the shortest and thickest ventricles. 

The wider ventricles and thick walls are beneficial to the chimps and football linemen because during high-intensity workouts when blood pressure in the arteries surge for a short amount of time, it ensures that enough blood is flowing to the brain to keep consciousness. 

The long-distance runners and the Tarahumara farmers are less likely to experience problems like high blood pressure and cardiovascular diseases because of their heart shape.

Fortunately, People’s heart shape is not permanent! Scientists suggest that changes in the heart shape is possible with endurance activities like swimming and running over the course of many years. 

So stop procrastinating and go for that run!

Sleep In for Heart Surgery!

Now if you’re on the operating table, likely passed out and opened up, its a fair bet that what time of day it is will have absolutely no importance to you. But maybe it should.

Recently, a study spanning over 6 years and conducted on over 600 patients, was based on recovering from heart surgery had noticed a strong correlation with time of day and rate/outcome of recovery.

These patients who underwent a heart valve replacement had shown an interesting relationship with a humans circadian rhythm. Those who underwent surgery in the afternoon had much better results and recovery than those in the morning. Additionally, in the following 500 days after the surgery, patients who were operated on during the afternoon were half as likely to have a major cardiac event such as myocardial infarction (commonly known as a heart attack) or acute heart failure.

The team conducted a second study in which a total of 88 random patients were put into two groups, morning and afternoon. The results showed that those in the afternoon had lower levels of myocardial ischemia.

In a further examination of these findings in an attempt to find a cause, an article from Scientific American states, “The researchers isolated heart tissue samples from a subgroup of 30 patients from the randomized controlled trial. In laboratory tests, tissue from afternoon surgeries more quickly regained its ability to contract when researchers imitated the process of the heart refilling with blood as surgery concludes.”

While operating in the afternoon may have its benefits, doctors say that altogether abandoning surgery in the morning is simply out of the question. However, other practical applications of this are being studied, such as how it may affect cancer treatment in patients and whether or not circadian rhythm affects a variety of medical procedures. But until then, let the anesthesia kick in and enjoy the operation.

What do you think will be the next application of circadian rhythm or other anatomical and biological features?

Want to find out more? Sources below.

http://www.telegraph.co.uk/science/2017/10/26/surgery-safer-afternoon-bodys-circadian-rhythm-study-suggests/

https://www.scientificamerican.com/article/why-heart-surgery-may-be-better-in-the-afternoon/

http://www.independent.co.uk/news/science/heart-surgery-afternoon-morning-safety-post-illness-recovery-circadian-rhythm-body-clock-a8023736.html

Australian and PNG doctors and nurses performing surgery in Operation Open Heart. Port Moresby General Hospital, Papua New Guinea. Picture by Rocky Roe/AusAID

Dr. Light

Cardiac arrhythmia is a problem with the rate of heart beat that currently affects 4 million Americans. During arrhythmia, the heart may beat too fast, too slow, or have an obvious irregular rhythm. In some cases, this heart condition may be life-threatening with the ability to damage the brain, heart, and other organs due to the lack of blood flow.

Oscar Abilez, a cardiovascular physician at Stanford University has developed the solution to this condition: light. With his team, he is working to create a new biological pacemaker that is able to control the heart with light. The first phase of his research involves optogenetics. This uses techniques from both optics and genetics to control the activity of individual neurons in living tissue. In 2002, German scientists were able to isolate the genes for the proteins called opsins. Before this discovery, algae and few other organisms were the only know carriers of light sensitive cells. These opsins, however, are responsible for cells’ light sensitivity in humans and modify the genetic code of other cells so that they, too, would produce these opsins. 

The next phase of his research involves stem cells. Oscar Abilez hopes to convert the stem cells light-sensitive cardiomyocytes from a person who is suffering from this condition.  These cells that make up the muscle tissue in the heart  would be able to be “grafted” onto a person’s heart. This would then ideally carry out Abilez’s vision, which he hopes will be achieved in the next decade or so, allowing physicians to control the whole heart’s rhythm using light.VPC_1

Defibrillators Malfunctioning?

Photo by: Stevenfruitsmaak

In almost every single public place you visit, you are bound to see an “AED found here” sign. An AED is an Automatic External Defibrillator. Not many people notice the defibrillators until they are needed in an emergency.

However, in a recent article, the Food and Drug Administration (FDA) released a statement saying that they will “toughen regulation of the industry that produces heart defibrillators.” Defibrillators are used to “jolt a failing heart back into its regular rhythm.” The FDA mentioned that there have been tens of thousands of malfunctions and hundreds of deaths over the past few years.

The article mentions that a nurse wanted to use an AED on a patient but failed to do so when the screen of the AED read “memory full.” Another case involved a software malfunction on the AED. When the AED was trying to be used, the screen read “equipment disabled.”

Since 2005, there have been 45,000 reports of the devices failing. Cardiac arrests, on the other hand kill as many as 400,000 people per year in the United States, we need the AEDs to work!

The FDA will now monitor the production of the devices. This is a pretty big job considering that there are about 2.4 million devices in public places around the United States.

 

 

 

Do You Really Want that Third Piece of Bacon?

This is a picture of a hamburger, which is a form of red meat often consumed by individuals everywhere. Found on Wikimedia Commons.

How many  people do you know that eat bacon every day?

What about a hamburger?

Did you know that the Harvard School of Public Health has recently discovered that red meat consumption can strongly contribute to cardiovascular disease and cancer, ending one’s life prematurely? These days, it is much healthier to eat “poultry, nuts, fish and legumes.” We need alternative sources of protein.

According to Nutrition researcher and author An Pan, who works at the Harvard School of Public Health,

“…eating high amounts of red meat has been associated with type 2 diabetes, coronary heart disease, stroke and certain cancers in other studies.”

It is scary to think that every time someone consumes red meat daily, there is a 13% increased chance of death. Eating processed meat is even worse because if eaten daily, there is a 20% increased chance of death. Every time someone consumes heme iron, carcinogens that are released from the meat during cooking, saturated fat, sodium and nitrates from his or her steak, these risk percentages rise. It has been researched that these risks can be weighted more heavily depending on “age, body mass index, family history of heart disease or major cancers.”

Now, we know that the protein replacements of fish (7%), poultry (14%), nuts (19%), legumes (10%), low-fat dairy products (10%) and whole grain (14%) have great percentages for lower risks of premature death. If people “eat less than 0.5 serving per day of red meat, 9.3% of deaths in men and 7.6% of deaths in women can be prevented.”

Mortality is an important factor for every individual to consider. Why waste life away to eat a slice of bacon each morning?

 

 

Broken Heart Syndrome?

Yes, it’s real…

"Radiology Picture of the Day"

Photo taken by Radiology Picture of the Day, Edited by Yasmin Kibria

The broken heart syndrome is a temporary heart condition brought on by stressful situations–both excessively happy or excessively sad or tragic moments.  The symptoms may be brought on by the heart’s reaction to a surge of stress hormones.  A flood of stress hormones and adrenaline causes part of the heart to enlarge temporarily and triggers symptoms that can look like heart attack: chest pain, shortness of breath, irregular heart rhythm. The difference is that the factors that would normally cause heart attack, such as a blocked artery, aren’t present.

The University of Arkansas performed a study which looked at rates of “broken heart syndrome” — when a sudden shock or prolonged stress causes heart attack-like symptoms or heart failure — and found that it overwhelmingly affects women.

Dr. Abhishek Deshmukh, a cardiologist at the University of Arkansas who has treated women with broken heart syndrome, became curious about just how gender-specific the condition was.He found that, overall, women had about 7.5 times the risk of broken heart syndrome as men; in people under 55, women were at 9.5 times greater risk than men. Women over 55 were also three times more likely to suffer broken heart syndrome than younger women.

Why does this gender imbalance occur? Researchers are still working towards finding an answer, but it has been speculated that hormones come into play.

The way to mend a broken heart? Literally let it heal over time–it’ll be fine soon enough.

For further information:

http://healthland.time.com/2011/11/17/study-women-are-more-vulnerable-to-broken-hearts/#ixzz1fGLHn6V4

http://www.cbsnews.com/8301-504763_162-57326698-10391704/broken-heart-syndrome-more-common-in-women/

http://theweek.com/article/index/221655/broken-heart-syndrome-a-real-health-issue-for-women
 

A big hearted snake

Credit: Flickr User Squamata55

For years the scientific community has been fascinated by the phenomena of snakes, such as pythons, eating massive meals at one time and breaking them down slowly over time.  Now thanks to a study by Leslie Leinwand there is an answer to how pythons manage this feat.  After the python eats its organs swell up to two times their size to accommodate this massive amount of digestion.  But what could cause an organ to swell this much?  Leslie and her team have an answer to this as well, fatty acids.  When they drew the snake’s blood after it ate they report that the blood was so filled with fat that it was opaque and it “looked like milk”.  Leslie and her team have not stopped their research here, in fact they learned that when they take three of the fatty acids found in the blood of these pythons and inject them into a living mouse the mouse’s heart will grow just like the pythons did.

This finding lead to another mystery for Leinwand and her team because they are still yet to discover how having large amounts of fat in the blood is harmless to a python while in a human it is incredibly damaging.  In an attempt to get answers Leinwand and her team have injected mice with heart disease with the three fatty acids that lead to heart growth to see if those lipids can have any effects on the condition.  Stay tuned…

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