#134 Phobia (English)

Phobia

What is a phobia?

A phobia is defined as being ‘a persistent, irrational fear of a specific object, activity, or situation that leads to a compelling desire to avoid it,’ by dictionary.com. This means that it is a very strong fear of a certain stimuli. It is considered an anxiety disorder.

How does someone get a phobia?

It is thought that for someone to get such an uncontrollable fear of something, environmental and genetic factors play a part. Although many people have phobias, it is still not known what exactly causes someone to have phobias. Phobias are related to anxiety as a phobia is an irrational fear of a certain stimuli. According to the National Phobics Society what may cause phobias to develop is stress, childhood environment, genetic predispositions, physical factors and even biochemical imbalances. It has been found that the weirdest phobias that some may have, have been caused by stress and the more common phobias may be caused due to childhood environment. Although this information is known, phobias are still not fully understood and people develop them due to certain factors and these are out of people’s control when it comes to the phobia.

How does someone get rid of their phobia?

Many phobias may not be very harmful to your everyday life so there is no problem in keeping this phobia. Others may be more harmful to a person to keep. It is important though to get rid of your phobia/phobias if your fear bothers you on a daily-basis such as stopping you from doing certain things, you recognize having an excessive fear or you’ve had this fear for over 6 months. To treat a phobia it is possible to either go through self-help or to undergo treatment. These two methods are the most effective so you must find the one that works best for you.

What are the most common phobias?

There are many phobias but the most common ones are:

1)       Arachnophobia – fear of spiders.

2)      Ophidiophobia – fear of snakes.

3)      Acrophobia – fear of heights.

4)      Necrophobia – fear of death or dead things.

5)      Cynophobia – fear of dogs.

6)      Claustrophobia – fear of confined spaces.

7)      Coulrophobia – fear of clowns.

8)      Pediophobia – fear of dolls.

9)      Hemophobia – fear of blood.

10)   Glossaphobia – fear of public speaking.

11)   Nyctophobia – fear of the dark.

12)   Trypanophobia – fear of needles.

13)   Agoraphobia – fear of situations where it may be difficult to find help.

14)   Pteromerhanophobia – fear of flying.

15)   Mysophobia – fear of germs.

What phobias do you have?

References:

·         http://www.helpguide.org/articles/anxiety/phobias-and-fears.htm

·         http://www.symptomfind.com/health/most-common-phobias/

·         http://news.bbc.co.uk/2/hi/uk_news/magazine/4837660.stm

PRM

#133 How weather affects your mood (English)

How weather affects your mood

 Do you ever feel slightly down when there’s a cloud in the sky? For some reason everything just seems so much worse! If only it could be sunny all the time right? Well, it has been proven that weather actually does have an effect on your mood!

 First of all, a lack of sunlight can cause Seasonal Affective Disorder, otherwise known as SAD – appropriate right? Well, this lack of sunlight causes more melatonin to be produced than normal. This is a hormone that tends to make you feel very sleepy. So since more is being produce, you consequently feel more tired. Your brain then starts to produce less serotonin, a neurotransmitter affecting mood, appetite and sexual drive. In order to combat SAD (most common between the months of October and April) it may be worth while to put your bedroom lights on a timer to create the illusion of a sun rise.

 Colder temperatures can also lead to laziness as they reduce sensory feedback, dexterity, muscle strength, blood flow, and balance, impacting your performance of complex physical tasks. If you tend to stay in bed in the early, cold mornings, piling on the layers and doing a morning stretch will help to wake you up as the added warmth and movement will stimulate blood flow.

 As well as making us a little bit more lazy, rain makes us eat more too… The lack of sunlight on a rainy day causes serotonin levels to drop which in turn increases our craving for carbohydrates. Once we’ve stocked up on carbs we feel better as they spark an increase in serotonin levels. However this spike does not last long and soon levels drop again. If you’re worried about eating too much pasta go for some starchy veggies instead!

 Rain can also cause pain. The likelihood of clouds or rain appearing in the sky increases as atmospheric pressure decreases. This allows bodily fluids to move from blood vessels to tissues, causing pressure on the nerves and joints, which leads to increased pain, stiffness, and reduced mobility. To help ease the pain skip the cardio for the day and do some nice relaxing yoga.

 On a positive note, research has shown that we spend less when there is less sunlight. Along with sun comes positivity and consumption so maybe you’ll be saving some money throughout the winter! Lucky you!

McA

#132 LASIK and LASEK Surgery (English)

LASIK and LASEK Surgery

 LASIK (Laser In-Situ Keratomileusis) is a type of refractive surgery for the correction of myopia, hyperopia, and astigmatism. The LASIK surgery is performed by an ophthalmologist who uses a laser or microkeratome to reshape the eye’s cornea in order to improve visual acuity.

Myopia, Hyperopia, Astigmatism

 The eye surgeon uses either microkeratome or femtosecond laser to create a thin, circular “flap” in the cornea. Before the incision, topic anesthetic drops are required to prevent any discomfort during the procedure. Also, the ink marker marks the cornea before creating the flap to indicate the incision area. Eye movements are prevented by fixing the eye by applying a suction ring. After the opening of the flap, the surgeon folds back the hinged flap to access the underlying cornea (stroma) and removes some corneal tissue using an excimer laser. Excimer laser is a form of cool ultraviolet light beam. It is used to ablate microscopic amounts of tissue from the cornea to reshape it so the retina more accurately focuses light and improve vision. For myopic people, the cornea is flattened, but for hyperopic people, the cornea is steeper. In case of astigmatism, the laser smooths the irregular cornea into a more normal shape. After the reshaping the cornea, the flap is then put back in place, covering the area where the corneal tissue was removed. Then the cornea heals naturally.

Microkeratome

 LASEK (Laser Assisted Sub-Epithelial Keratomileusis) is a type of surgery changing the shape of the anterior central cornea using an excimer laser to ablate a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium.

 The surgical procedure is similar to one another, yet he main difference is that LASIK surgery creates a thin flap including corneal stroma tissue in the cornea, whereas in LASEK the cornea’s entire epithelial layer is removed by trephine to expose the area. Like LASIK, LASEK uses the excimer laser then sculpts the stromal layer of the cornea to correct the vision.

Structure of the Cornea

 The healing and recovery take 2~7 days in LASIK. However, in LASEK, it takes about 4~7 days to recover, which is slightly longer than LASIK. LASIK is appropriate for people who have adequate thickness of corneal tissue. People with less corneal tissue proceed LASEK surgery. In LASEK surgery, more corneal tissue is preserved after the procedure.  

[Reference]

https://en.wikipedia.org/wiki/LASIK
https://en.wikipedia.org/wiki/Excimer_laser
http://www.allaboutvision.com/visionsurgery/lasik.htm
https://en.wikipedia.org/wiki/Photorefractive_keratectomy
http://www.allaboutvision.com/visionsurgery/prk.htm
http://www.the-lasik-directory.com/lasik_lasek_chart.html

LASIK surgery procedure

https://www.youtube.com/watch?v=UezYWOqPQ_Q

Comparison of LASIK and LASEK surgery

https://www.youtube.com/watch?v=dKANhIU7Sxk

KSJ

#131 Cryobiology (English)

Cryobiology

Cryobiology is the study of the effect of low temperatures on living things. In nature, freezing temperatures have been used to figure out different organism's coping mechanisms.

Bacteria

Some bacteria have been able to survive after being frozen in ice for thousands of years. Some bacteria produce proteins that are used for ice formation on the surface of plants and fruits. This causes injuries to the epithelium which is the cells that line the outermost layer of an organism and allows the bacteria to gain access to the nutrients in the plant tissues.

Plants

Plants go through hardening, which is when plants become tolerant to the effects of freezing for weeks to months. There are three stages in this process. Firstly, carbohydrates are moved to the roots of the plant and the permeability of the cell membrane increases. Once these two changes have occurred the plant will be able to tolerate temperatures from -5°C to -10°C. The second stage is when cell membranes are chemically altered to allow plants to survive temperatures around -20°C. In the final stage, vitrification will occur. Vitrification is to convert something into glass or a glassy substance by heat and fusion. With water, vitrification is rapid cooling where the temperature drops rapidly in megakelvin per second. When vitrification occurs, instead of crystallizing, a solution would be in a state like a 'solid liquid' which occurs at a certain temperature range known as the glass transition temperature, which differs for different types of material.

Animals

Vitrification has also been used in animals. A rabbit kidney was vitrified to -135°C. Once it was re-warmed and transplanted into the rabbit, it was able to keep the rabbit alive as the only functioning kidney. Vitrification has also been used to preserve human egg cells which were later fertilized and grew into a normal functioning human. Human gametes can survive at -196°C for ten years under controlled laboratory conditions after cryopreservation.

Risks

The main risks to cells during cryopreservation include:

1.    Extracellular ice formation- when tissues are cooled, water migrates out of cells and ice forms. Too much of this ice can cause damage to cell membranes due to crushing. However, some tissues and organisms can tolerate this

2.    Intracellular ice formation- if intercellular ice forms, it is almost always fatal to cells

3.    Dehydration- the movement of water to the outside of the cell causes dehydration which could potentially cause damage

How to Prevent Risks

1.    Slow freezing- Intercellular freezing can be prevented if cooling is slow enough to allow water to leave the cell. The rate of cooling varies but is around 1°C for most mammals but varies for other types of cells.

2.    Vitrification- See above

References:

https://en.wikipedia.org/wiki/Cryobiology
http://www.merriam-webster.com/dictionary/vitrified
http://www.scienceclarified.com/Co-Di/Cryobiology.html
http://www.scienceclarified.com/knowledge/Cryopreservation.html

PoS

#130 Distraction Osteogenesis Surgery (Mandibular Distraction) (English)

Distraction Osteogenesis Surgery (Mandibular Distraction)

 Distraction osteogenesis is a procedure that uses the healing process that occurs between surgically osteotomized bone segments and is also a prominent aspect of reconstructive surgery. Osteotomy indicates the incision or transection of a bone.

 The surgical therapy is divided into presurgical phase, operative phase, lag phase, distraction phase, consolidation phase, and retention phase.

 In presurgical phase, based on the radiographic studies, the orthodontist determines whether an internal or external device is more suitable for the procedure and the vector of the distraction.

Mandibular Fracture

 In operative phase, the mandibular distraction can proceed when there is enough mandibular bone stock must be available for the osteotomy and placement of the device. The choice between the use of internal and external device is made mostly based on the degree of bony and soft-tissue exposure for placing the device to make maxillary-mandibular opening. The external devices facilitate multidirectional control of the distraction of which the internal devices are not capable. On the other hand, the external devices require multiple skin incisions which may derive facial scars. Either devices can navigate the distraction vector. To avoid injury to the inferior alveolar nerve and the developing dentition during the procedure, perpendicular osteotomy line is demanded. The placement of the distractor before the making the osteotomy can prevent the mobility of the proximal segment. The surgeon employs standard principles of a sagittal split osteotomy when lengthening the mandibular body. The nerves are preserved by using a reciprocating saw (fig 3) for the buccal corticotomy (fig 4), and the lingual cortex (fig 1) is fractured with an osteotome (fig 2). Patient will feel discomfort until fracture is completed.



 In lag phase, there is a latency period to allow for initial bone formation to happen. This phase endures for average 3~5 days. However, patients with skeletal maturity, the latency period lasts for 5~7 days.

 In distraction phase, the bone segments are gradually pulled apart using either an internal or external device. The rate of distraction is normally set to 1.0mm per day. Exceptionally, for infants, the rate is intentionally accelerated to 2.0mm per day to prevent early consolidation and for elders, the rate is decelerated to 0.25~0.5mm per day. The distraction can occur at once or in several increments throughout the day depending on the rhythm or frequency of distraction. Based on the patient’s demographics, the total time of the distraction phase is customized.

 In consolidation phase, once the anticipated bone length is approached, the mineralization of the immature bone occurs. The distracting appliance is fixed into place to provide stability until the immature bone has adequate strength to sustain. This phase varies in time, but in average, it takes 6~8 weeks.

 In retention phase, the device is removed. This step may require occlusal splints to guide the maxilla into position when the leveling of the mandibular cant creates a posterior open bite.

[Reference]

https://en.wikipedia.org/wiki/Distraction_osteogenesis
https://en.wikipedia.org/wiki/Corticotomy
http://medical-dictionary.thefreedictionary.com/osteotomy
http://emedicine.medscape.com/article/1280653-treatment

KSJ

#129 Risks of CT and MRI (English)

Risks of CT and MRI

CT Scanner

 A computerized tomography (CT) scan combines a series of X-ray images taken from various angles and uses computer processing to create cross-sectional images of the bones, blood vessels and soft tissues inside the body. Thus, CT scan provides more precise image than plain X-rays do. In the CT scanner, the X-ray tube rotates around the patient. The X-ray detector on the opposite side receives the beam that penetrates it through the patient. The signal received by each and 764 channels is digitized to a 16bit value and sent to the reconstruction processor. Measurements are processed about 1000 times per second. Based on the calibration scan data of air, water and polyethene, previously acquired in the exact same relative location, scan data from each channel is compared. The comparisons lead to materializing the image pixels to have a known value for particular substance in the body regardless of differences in patient size and exposure factors.





MRI Scanner

 Magnetic resonance imaging (MRI) is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body. Using a very strong magnet and pulsing radio waves, the detection coils in the MRI scanner read the energy produced by water molecules as they realign themselves after each RF alignment pulse. The collected data is reconstituted into 2D image through any axis of the body. Bones are essentially void of water and accordingly, do not generate any image data. Consequently, bones are not indicated on the images.

 

 There are many risks appertained to CT and MRI. For instance, the amount of radiation released by a CT scan is about one in three hundred chance of a CT scan spurring a cancer, and this may be fatal for young and pregnant women. Although MRI scanners do not emit radiation, it builds up a very powerful magnetic field to stimulate the atoms in the patient’s body. The excited atoms release a type of energy, and it is detected by the scanner. Not only does this magnetic field instigate the atoms but also heats up the metal that may be present inside patient’s body. Furthermore, the use of contrast agents, dyes that highlight the blood vessels, in CT like iodine can be lethal for patients will iodine allergy. Also, the contrast agents of MRI scanners, highlight lesions that cause a breakdown in the blood-brain barrier, like gadolinium could case nephrogenic systemic fibrosis for people with kidney disease.

MRI Image of the Brain
Before and After Injections of Gadolinium

 Blood-brain barrier is a highly selective permeability barrier that separates the circulating blood from the bran extracellular fluid in the central nervous system.

[Reference]

http://www.mayoclinic.org/tests-procedures/ct-scan/basics/definition/prc-20014610
http://www.nhs.uk/conditions/MRI-scan/Pages/Introduction.aspx
http://www.diffen.com/difference/CT_Scan_vs_MRI
http://neurology.about.com/od/Radiology/a/MRI-vs-CT.htm
https://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier

KSJ

#128 Intracerebral Haemorrhage Surgery (English)

Intracerebral Haemorrhage Surgery

 Intracerebral haemorrhage occurs when a weakened or diseased blood vessels rupture, so the blood leaks inside the brain. The abrupt increase in pressure within the brain (hypertension) prompt the brain cells surrounding the blood to damage. When the amount of blood released increases rapidly, the sudden buildup in pressure can spur unconsciousness or death. Intracerebral haemorrhage usually occurs basal ganglia, cerebellum, brain stem, or cortex.

 Hypertension is one the most typical factors causing intracerebral haemorrhage. It often doesn't cause any symptoms. Consequently, majority of patients suffering from Intracerebral haemorrhage are not aware that they have high blood pressure. The other factors like head trauma, aneurysm, arteriovenous malformations, amyloid angiopathy, liver disease, and brain tumors lead to intracerebral haemorrhage.

Aneurysm is a weakening in a blood vessel wall that swells.

Arteriovenous malformations are the weaknesses in the blood vessels in and around the brain.

Amyloid angiopathy is an abnormality of the blood vessel walls.

 There are various surgeries regarding intracerebral haemorrhage: decompression surgery, craniotomy with open surgery, simple aspiration, endoscopic evacuation, and stereotactic aspiration. The surgery will proceed depending on the age, the other health issues that the patient might possess, the degree of brain damage, and the location of the haemorrhage and haematoma.

 Decompression surgery is alleviating the blood pressure by removing the pooled blood and repairing damaged blood vessels. Pooled blood is the blood that could not return to the heart due to the malfunctioning of the walls and valves of veins in the brain. Evacuating haematoma, a solid swelling of clotted blood within the tissues, relieves the blood pressure.

 Craniotomy with open surgery is the removal of a portion of the skull accompanied by the open surgery to evacuate the haematoma and repair the ruptured blood vessel. This is a surgical procedure that is used when the haematoma is very large, so the critical functions weaken.

 Simple aspiration is when the surgeon drills a small hole in the skull and evacuates the haematoma using a needle. Finding the exact location of haematoma is demanding. Also, the complete evacuation of haematoma is not possible.

Stereotactic head fram
© Alzforum

 Endoscopic evacuation involves drilling a hole in the skull like simple aspiration but it is a more acute procedure as it involves using an endoscope to navigate the needle. Endoscope is a tiny camera-guided instrument.

 Stereotactic aspiration proceeds the surgery based on the computed tomography (CT) that indicates the location of the haematoma. Also, the evacuation of haematoma is done by a specially developed suction too. During this surgery, the patient’s head is fixed in a stereotactic head frame, so the procedure is done at a greater degree of precision and accuracy.

[Reference]

http://www.strokecenter.org/patients/about-stroke/intracerebral-hemorrhage/

http://www.webmd.com/brain/brain-hemorrhage-bleeding-causes-symptoms-treatments

http://weillcornellbrainandspine.org/condition/intracerebral-hemorrhage/surgery-intracerebral-hemorrhage

KSJ