Tag Archives: Sleep

Sleep Deprivation Can Cause Changes in Genes?

Posted on March 4, 2013 by | 3 comments

A sleeping child (Cr. JarektUploadBot via Wikimedia Commons)

Are you getting enough sleep lately?  You probably know that sleep deprivation is bad for you, but to what extent?  Now, a study showed that a lack of sleep affects the gene mechanisms that control metabolism, sleep and immunity.  Just one week of insufficient sleep can cause changes to over 700 genes!  Yikes!

Before this study was done, scientists linked long-term sleep deprivation with obesity, heart disease and cognitive impairment.  However, the actual molecular mechanisms that led to these effects were not known.

The effects of sleep deprivation (Cr. Mikael Häggström via Wikimedia Commons)

Now, British researchers at Surrey University in England showed that long-term sleep deprivation directly alters gene expression for processes such as immune responses, stress and metabolism.  All of the above mentioned affects have a wide range of negative effects, especially if the health issues last a long time.

In this study, researchers had 26 healthy volunteers (as in, no illnesses), but were deprived of sleep.  They then examined the gene expressions in the volunteers.  The people in the “sleep-deprived” group only had about 6 hours of sleep for 7 days consecutively, while the people in the control group had about 10 hours of sleep.  At the end of the week, participants had their blood RNA samples taken.

Both groups were observed and had many tests taken to determine their cognitive performance during the day.  The participants in the study were also asked how they slept.  Finally, researchers measured levels of the hormone melatonin, which regulates biological rhythm and sleep cycles.

The chemical structure of RNA (Cr. InfoCan via Wikimedia Commons)

RNA analysis of the blood samples showed that activity in 711 genes were decreased or increased from the lack of sleep.  As it turns out, every gene is responsible for the creation of a protein that is important in the body.  And RNA is needed to carry out the message from each gene to create those proteins.  If the amount of RNA changes from its normal levels, then this means that there are now more or less of the messages getting sent to create the proteins.  This can ultimately lead to dramatic changes in the body.

Changes to different genes caused different reactions.  Many of the genes that were affected were involved in maintaining the “biological clock” or the circadian rhythm.  It is what tells us what is supposed to happen in a 24-hour clock.  Other genes were known for their overall gene expression – that is, the lack of sleep will cause harmful changes to the body.  Finally, through the study, it was shown that participants also had bad test results on memory, cognition and attention.

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Here’s a short overview on sleep deprivation and its effects on genes! (via. Youtube user: DNewsChannel)

So, what exactly should we take from all of this?  It’s definitely time to sleep more!

– Maggie Chan

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Posted in Biological Sciences, Issues in Science, Science in the News

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Insight on Eyesight: Vision Correction While You Sleep

Posted on February 11, 2013 by | 7 comments

“You wore glasses before?”
“Yup.”
“Are you wearing contact lenses right now?”
“Nope, I only wear them when I sleep.”
“What?! You can do that?”

That was the typical response I got when people found that I wore contact lenses to sleep. At a very young age, I developed a common eye condition known as nearsightedness or Myopia; I could only see close objects clearly and objects far away appeared blurry. As my eyesight got worse at an abnormally fast rate, my optometrist (a doctor specializing in eye care) recommended me to wear “night lenses” to correct my vision, a practice known as Orthokeratology (Ortho-k).


Some Ortho-K lenses that I own
Copyright: Grace Lam 

How do you develop Myopia?

Myopia is typically an inherited condition and often develops in children ages 8-12.  This condition progresses very quickly at young ages due to the rapid growth of tissues in the eye while the eye is constantly elongating (growing in the forward-backward direction). Also, engaging in “close-up activities” such as reading and using the computer for extended periods of time can speed up the development of nearsightedness.

In order to see objects clearly, the image of the object must be focused on the retina. This is done by the lens in your eye (see image below), as it thickens when looking at close objects and flattens when looking at objects far away. According to researchers at the Ohio State University College of Optometry, the lens in patients with Myopia do not thin or flatten out like those of normal individuals. This causes the image to be focused in front of the retina rather than directly on it, thus resulting in a blurred image of objects that are far away.


The main areas of the eye affected in Myopia
by the National Eye Institute via Wikimedia Commons

How does Orthokeratology help?

The purpose of Ortho-k is to provide vision correction without the complications of surgeries and since changes cannot be made to the lens without opening up the eye, the shape of the cornea is altered instead (see image above). This is accomplished by wearing specially fitted contact lenses when sleeping.  As the cornea is also an important structure that helps focus images perceived by the eye, altering its shape effectively can compensate for the shortcomings of the lens and ultimately refocus the image back on the retina. As a result, myopic patients can once again see objects at close and far distances clearly. Check out the video below for more on Myopia and Orthokeratology.

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Youtube video by EyeContactOptometry

Research has shown that the use of Ortho-k lenses slow the progression of myopia, which is important to many myopic patients. I prefer night lenses because I can’t feel them when I sleep and when I take them off in the morning, I have 20/20 vision just like everyone else. Orthokeratology may not be the right treatment for everyone, but it can be advantageous for those who find glasses and day lenses inconvenient.

– Grace Lam

 

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Posted in Biological Sciences

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Nighty night~

Posted on February 3, 2013 by | 2 comments

Have you ever wondered what’s going while you’re sleeping? Well the truth is there is a lot going on during the period of time you are asleep and it is divided into five stages. Using an electroencephalograph (EEG) we can determine the stage of sleep we are in.

A sleeping baby by oksidor via Flickr Creative Commons

Early stages of sleep prior to stage one:

Before phase one, our mind is relatively alert and therefore we experience hypnagogic hallucinations, such as experiencing the sensation of falling, and myoclonic jerks, an involuntary twitching of the muscles. Furthermore, our brain starts to produce small and fast waves known as beta waves. As the mind slowly beings to relax, slower waves called alpha waves are produced.

Stage one:

During this period, we are in the relatively light stage of sleep, and is often considered as the transition between being awake and falling asleep.  It lasts for a brief amount of time, and usually when people wake up during this stage, they feel like they haven’t slept at all. The waves that are produced during this time is called theta waves, which are slow, high amplitude waves.

Stage two:

The body temperature starts to drop and heart rate slows down. At the same time the brain produces short periods of quick rhythmic waves known as sleep spindles. 

Stage three:

This is the period between light sleep and deep sleep. Slow, deep waves called delta waves are produced.

Stage four:

Delta waves continue to be produced, therefore this period is also known as delta sleep. This stage typically lasts for about half an hour and we fall into a deep sleep. Generally bed-wetting and sleepwalking occurs during this stage.

Stage five:

This phase is commonly known as rap eye moment (REM) and we enter this stage approximately 90 minutes after falling asleep.  Typically we enter REM sleep four to five times during the night, and each time the duration of REM sleep increases. During this period, the muscles become relaxed to a point where the body is paralyzed while respiration rate and brain activity increases. Due to the increase in brain activity, this is the time when most of our dreams occur. 

Here is an example of what an EEG looks like:

EEG when awake and during the different stages of sleep via http://www.nature.com/nri/journal/v4/n6/fig_tab/nri1369_F1.html

Although the above EEG depicts the stages of sleep from stage one to five in order, the stages do not actually occur in this sequence. After falling asleep, we begin in stage one, and progress into stages two, three and four. After stage four, stages three then two is repeated prior to entering REM sleep. After REM sleep, we return to stage two. Throughout the night we cycle through the above sequence four to five times.

Below is a video about the five stages of sleep:

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From YouTube user: Shannon Leigh

Now that you know more about the different stages of sleep, the next time you watch The Big Bang Theory and Sheldon mentions REM sleep, you’ll know what he’s talking about!

– Alice Lin

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Posted in Biological Sciences

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