#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

#127 Hombres vs Mujeres_Diferencias en tema deportivo (Español)

Hombres vs Mujeres

Diferencias en tema deportivo

Por supuesto, los hombres y las mujeres no son iguales, así como tener órganos reproductores diferentes, hay ciertos aspectos que se diferencian según el sexo, los que pueden tener un afecto en el resultado deportivo.

•   Morfología: la Mujer tiene un tamaño entre 7 y el inferior de 10 cm a hombres, pesa aproximadamente 10 kilogramos menos y tiene entre 4 y 6 kilogramos más gordos. Además, los hombres tienen más masa de músculo, tienen miembros más largos y el torso es más amplio debido a sus hombros más distantes. Para todo esto, las mujeres tienen la cierta desventaja mecánica que le previene levantar más peso y desarrollan menos fuerza. Sin embargo, la elasticidad está a la altura el 10 % más alto en mujeres, como la movilidad conjunta.

•   Hormonas: La testosterona presente en las mujeres es alrededor de una décima que la que poseen los hombres, y debido a la influencia de esta hormona en el desarrollo de la fuerza y los músculos, las mujeres tienen menores posibilidades de desarrollar igual fuerza y tamaño muscular que los hombres, aún cuando se ejercitan de la misma forma. Además las mujeres tienen más estrógeno, hormona femenina que interfiere en el crecimiento muscular e incrementa la grasa corporal.

•   Estructura muscular: La genética ha determinado que las mujeres tienen menor masa muscular en el tronco, respecto a los hombres, como así también, son capaces de producir unos dos tercios de la fuerza de un hombre. Sin embargo, en la parte inferior del cuerpo las diferencias de fuerza son menos notorias, e incluso, si se toma en cuenta la fuerza en relación a la masa muscular de que disponen las mujeres, ésta es ligeramente superior en el sexo femenino.

En términos generales, las mujeres tiene ciertos condicionamientos que impiden que la fuerza sea la misma que en los hombres. Asimismo, el tamaño muscular suele ser siempre superior en los hombres y éstos se visualizan más musculosos por poseer más masa muscular.

•   Gasto metabólico: El gasto del metabolismo basal en las mujeres resulta menor que en el hombre: en una mujer joven, el gasto medio es de unas 37 kcal/m2/hora lo que significa un consumo calórico al día de unas 1.300 kcal. En el hombre este consumo se eleva a los 40kcal/m2/hora y unas 1.700 kilocalorías al día.

•   Cintura pélvica más amplia en las mujeres: Esto está relacionado con la función reproductiva. Por todo ello, las mujeres presentamos un abdomen comparativamente mayor. Esta disposición supone desventajas biomecánicas. Producirá un mayor balance lateral en cada zancada, siendo por tanto una desventaja mecánica durante la carrera. También presenta una mayor curvatura de la columna vertebral a nivel lumbar, lo que produce un riesgo en trabajo con cargas pues implica unas lordosis lumbares forzadas y un mayor riesgo de sobrecargas o lesiones.

•   Sudoración: Por regla general, las mujeres sudamos menos que los hombres, nuestros niveles de transpiración son menores. La función termo reguladora para enfriar la piel tiene una respuesta más lenta, sin embargo, no nos deshidratamos con tanta facilidad, lo cual es una ventaja para los deportes de resistencia. Los hombres deben hidratarse más que las mujeres.

AAM

#126 What are taste buds? (English)

What are taste buds?

Taste buds are universally known for being responsible for your ability to taste flavours, but most people have no idea the depth of their involvement in the body's survival instincts. Here are some surprising facts about taste buds that you probably don't know.

1.    Taste buds are not visible

The bumps on your tongue's surface are not actually taste buds, they are fungiform papillae, which each have an average of six taste buds buried with in its surface tissue. Taste receptors in the taste buds allow us to distinguish between tastes, such as sweet, salty and sour, by sending messages to the brain. Taste buds are also located on the roof of e mouth, throat and inside the stomach.

2. Individuals have different numbers of taste buds

The average adult has between 2000 and 10000. People who have more than 10000 are called "supertasters" because they taste things more intensely. Supertasters may not like vegetables as they can taste overwhelmingly bitter to them or very rich desserts as they can be overly sweet.

3. Taste buds are designed to keep us alive

Our ability to distinguish between flavours was designed as a survival mechanism in which the tongue tells the brain whether or not to swallow what is in the mouth. Infant are born with a preference to sugar and not bitterness. This is because natural sugar is an original source of fuel for the brain, whereas bitterness signaled poison so the taste system developed to protect the body from ingesting poison. Also, sodium is a mineral that helps make our muscles and nerves work, thus being the reason why many people crave salty foods.

4. Taste preferences can fluctuate with hormones

During early pregnancy, many women cannot stand to eat vegetables. This is supposedly due to their bitt taste being a signal for poison, so the brain becomes hardwired to avoid these foods so to protect the baby. Also, pregnant women tend to crave foods high in energy (like sugars and carbohydrates), hence the common pregnancy for sweets and desserts.

5. Taste buds are always regenerating

All taste buds go through a life cycle where they grow from basal cells into taste cells, then die. They are then sloughed away. A normal life cycle in an adult for a taste bud is usually from 10-15 days. Burning the tongue with hot foods can also kill taste cells, but they grow back which is the reason why taste doesn't deteriorate with age.

SJS

#125 Realization of Personalized Drugs (English)

Realization of Personalized Drugs
[TEDxBoston: ‘Body parts on a chip’ by Geraldine Hamilton]

The pharmaceutical industry is always faced with challenges in discovering and developing new drugs. What could be the reasons for the industry to experience supply shock of therapies? The development of new drugs demand vast amount of financial investment and time. More importantly, there is a subtle chance of success.
 

There are two principal techniques available to test the efficacy and the safety: cells in dishes and animal testing. As mentioned beforehand, there are constraints in both of them. In case of cells in dishes, the human cells are placed in dishes and examined in an environment that has no such resemblance of the actual body. The animal testing provides various practical information on the effect on complex organism, however, animal models founder to anticipate the actual effect on human body. As a result, these methods are inadequate for the development of successful drugs as they fundamentally fail to create the dynamic environment of the body.

Wyss Institute, medical research institute, came up with a great solution. The revolutionary invention of “organ-on-a-chip”. An organ-on-a-chip is a multi-channel 3-D microfluidic cell culture chip. This chip is the smallest functioning unit with the function and the mechanical strain that cells experience in our body.

Lung-on-a-chip ⓒ Wyss Institute



1) The white blood cell in the layer of capillary cells
2) The white blood cell going through the pore of the membrane
3) Phagocytosis of the bacterial cell by the white blood cell
ⓒ Wyss Insitute

Observing the lung-on-a-chip, there are three fluidic channels: lung cells on top, porous flexible membrane in the center where cells are cultured, and capillary cells from the blood vessels underneath. The vacuum channels on the sides apply mechanical forces to the chip, so that the cells experience the exact motions as they would in the actual lungs. The bacterial cells are added to the layer of the lung cells, and human white blood cells are released in the layer of the capillary cells. The white blood cells move through the pores of the membrane in the center and reach the other side where they engulf the bacteria (phagocytosis). In fact, the chip has successfully demonstrated the immune response in our body. In other words, chips will create models of diseases and carry out trials on the dynamic responses to potential new treatments. There is a pipeline of chips for different organs such as liver, gut, lungs, heart, and bone marrow. Thus, we can interconnect multiple different chips together to construct a virtual human-on-a-chip.

ⓒ Wyss Institute

In clinical trials, it is impossible to test all the different yet clinical trials-on-a-chip is the perfect solution for this limitation. Simply extract targeted stem cells of the patient and put them on a chip and create a personalized chip to develop drugs that would compensate individual differences.

Reference

https://www.ted.com/talks/geraldine_hamilton_body_parts_on_a_chip#t-476915

http://wyss.harvard.edu/staticfiles/pdf/Microfluidic%20organs-on-chips.pdf

https://en.wikipedia.org/wiki/Organ-on-a-chip

KSJ

#124 L'Alcool porte atteinte aux neurones (Français)

L’Alcool porte atteinte aux neurones

On pense souvent qu’une trop grande quantité d’alcool porte préjudice. Pourtant, la vérité pourrait être bien plus grave. Mickaël Naassila, directeur du Groupe de recherche sur l’alcool et les pharmacodépendances à l’université de Picardie, affirme que l’effet de l’alcool est néfaste. Ce propos est appuyé par des travaux de recherche. Par exemple, il existe une théorie que l’alcool altère l’activité des récepteurs situés à la surface des neurones. Cette modification a un effet sur la stimulation ou la prévention du passage de certains ions. Par conséquent, l’équilibre des échanges entre le neurone et le milieu extérieur est interrompu et ce déséquilibre provoque la mort des neurones.

D’ailleurs, l’alcool s’infiltre à l’intérieur des cellules et y augmente le stress oxydant. De plus les différentes protéines essentielles telles que l’ADN se détériorent. Au dernier lieu, il déclenche la libération de molécules inflammatoires. Ceux-ci provoquent la mort des neurones. Non seulement la mort neuronale, mais aussi le taux de la naissance des neurones diminue.

L’alcool a, en outre, un effet néfaste sur le nombre de neurones. Il mène à l’affaiblissement des connexions neuronales et à la dégradation de la myéline. La myéline est une couche isolante et une gaine protectrice des fibres nerveuses. Elle hâte les impulsions électriques le long des cellules nerveuses.

L’ivresse réduit la neurogenèse particulièrement dans le cerveau des adolescents. C’est la raison pour laquelle il existe plusieurs campagnes qui interdisent carrément la consommation d’alcool chez les adolescents. En fait, les répercussions de l’alcool dans le cerveau des adolescents sont plus graves que dans le cerveau des adultes. C’est sur le fœtus que l’effet est le plus nocif et dans certains cas, on verra l’apparition de handicap mental non génétique.

Malgré l’effet nocif de l’alcool, la consommation fréquente de l’alcool augmente la tolérance physiologique à l’alcool. Le récepteur GABA_A joue un rôle essentiel dans le développement d’une tolérance à l’alcool. L’alcool modifie la structure des sous-unités du GABA_A et diminue l’affinité du récepteur à l’alcool. De ce fait, à la longue, la même quantité d’alcool causerait des effets moindres.

C’est irréfutable que l’alcool dégrade la fonction neuronale. Par conséquent, l’alcool est classifié comme antidépresseur qui ralenti la rapidité d’action et de reflexe. Pour maintenir votre santé, je vous suggère de réduire votre consommation d’alcool.

Référence

http://www.science-et-vie.com/2015/07/lalcool-detruit-il-les-neurones/

https://fr.wikipedia.org/wiki/R%C3%A9cepteur_GABAA

KSJ

#123 Les pigeons diagnostiquent les cancers (Français)

Les pigeons diagnostiquent les cancers

Les pigeons possèdent un incroyable talent. Ils sont capables d’identifier et de déterminer les cancers grâce à leurs aptitudes à s’orienter et leur mémoire visuelle. C’est un stéréotype répandu que les pigeons sont balourds et inintéressants. Cependant, dans le domaine de la cancérologie, personne ne pourrait dénigrer leur don. En fait, les pigeons qui sont bien dressés seraient capables de vérifier des cellules ou des tumeurs cancérigènes sur des images de grandeur microscopique. La moyenne de réussite de reconnaissance des cellules atteintes de cancer, sur plusieurs clichés – incluant des clichés sans pathologies – est de 75 à 85%. En comparaison avec les oncologues qui réussissent à 97%, les pigeons manquent de précision. Néanmoins, ce résultat contribue de façon significative au développement des nouvelles technologies d’imagerie médicale voire de reconnaissance automatique.

Il existe divers animaux, tels que les chiens et les cricétomes des savanes, qui ont des talents qui servent la médecine. Toutefois les pigeons les surpassent significativement. Selon des chercheurs de l’Université de Californie et de l’Université de l’Iowa, les capacités des pigeons sont incroyables. Autrement dit, leur compétence à diagnostiquer des cancers concurrence celle des cancérologues.

Actuellement, les chercheurs affirment que le système visuel remarquable des pigeons est associé à leur faculté. Pour augmenter le taux de réussite, les pigeons sont entraînés pendant 15 jours dans le laboratoire. Avant le dressage, le taux de réponses correctes est de 50%, tandis qu’au final, les pigeons sont capables d’examiner des clichés divers à différentes échelles ou directions.

Le pigeon est placé devant un écran comme montre l’image au-dessus. Il doit taper du bec sur un rectangle bleu ou jaune d’après la présence ou non de cellules malignes. Si la réponse est juste, le volatile reçoit une petite gourmandise dispensée par un système automatique.

Bien que les pigeons excellent dans la reconnaissance de la présence de cellules cancérigènes, les expériences menées par les chercheurs montrent que leur compétence possède une limite avec une incapacité à distinguer les cas bénins des cas malins. Cependant, leur talent va être consacré à l’avancée des recherches portant sur le cancer.

Référence

http://www.science-et-vie.com/2015/11/les-pigeons-demontrent-une-incroyable-capacite-a-identifier-des-cancers/

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