Tag Archives: Disease

How does our immune system work ?

We are constantly encountering pathogens (anything that can cause disease), so why don’t we become sick more often?
The answer to this question is our immunes system, which is responsible for protecting us from diseases.

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                                     The immune system
                      Credit: In a nutshell – Kurzgesagt

From a scientific point of view, the immune system includes many biological structures and processes that an organism has in order to response to diseases that come from bacterial or viral infections.
The immune system reacts to diseases with layered defenses of increasing specificity. There are two lines of defenses in our body: 1- innate defenses, 2- adaptive defenses

Cells of Immune system      Credit: Wikimedia

The innate defenses include two major parts. In the first part, there are physical barriers such as a tough outer skin, mucous membranes and secretions that are all impenetrable to viruses and bacteria. In the second part, which is more detailed, body protects itself by phagocyctic cells and natural killer cells, which are white blood cells. In addition to these white blood cells, complement proteins and the inflammatory response (swelling, fever and redness) also play important roles in this kind of defense.
After innate defenses, there is a more specific line of defense, which is called adaptive immune response. This kind of defense provides immunity against particular pathogens that the innate immune response is not able to kill and remove them. T cells and B cells are lymphocytes that play the most important role in the adaptive immune response.
B cells respond to presence of pathogens by recognizing them, secreting antibodies which are types of proteins that bind to pathogens and inactivate them and create the memory of them.
The last part of the adaptive immune response is T cells. These cells have receptors on their surface and use them in order to recognize infected cells, kill invaders and stimulate more B cells.

Adaptive immune response        Credit: Wikimedia

Kamyar Kazemiashtiani

Who’s this stranger starring at me?

Can you imagine if one normal day, as you are getting ready to leave the house, you take a glance at yourself in the mirror and see a complete stranger? That person looks just likes you, speaks the same way you do and has done the same activities in life as you have. The only problem is, you do not realize the fact that you are looking at your own mirror image because the person you see is an unknown intruder.

By State Library of New South Wales collection [No restrictions], via Wikimedia Commons

A similar situation happened to an elderly man in France who could not recognize himself in the mirror and started conversing with the stranger he saw replacing his reflection. After his daughter took him to the hospital, doctors diagnosed this man with a rare condition called Atypical Capgras syndrome. While in the typical case of this syndrome, patients think that a family member or a friend has been replaced with an identical impostor, in the atypical case the patients’ delusions concern his own self.

By Andraž Blaznik (email) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

According to neurologists and psychiatrists, people who have this disease have impairments in two separate brain pathways. The overt pathway or direct pathway is impaired, prohibiting the patient from recognizing faces but allowing them to show emotion towards a particular face, and the covert pathway is impaired, where even though patients can identify a familiar face, they show no signs of familiarity related to that face. The Atypical Capgras syndrome causes patients to recognize themselves as strangers. The Youtube video below shows an actual case of the typical Capgras disease.

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By Canale di Cogmonaut

People who suffer from this disease can be helped by certain anti-psychotic medications. Due to the rareness of this disease further investigations on methods and drugs that can cure it are currently taking place.

All in all, apart from our brain being a miraculous organ capable of receiving, organizing and distributing information to make our bodies function properly, it can also work in reverse, preventing us from recognizing our own mirror reflections. So next time you look at yourself in the mirror, be grateful that you recognize that awesome person standing right in front of you because some have to face a scary reality where they start to question their own identity.

By Doris Stratoberdha.


I have two mommies and a daddy

You are probably now wondering if you read that title correctly. Well I assure you that you did. Science has yet again found a way to surprise us all by creating in vitro fertilized babies that have genetic material from two females and one male. The process is called ” three-parent in vitro fertilization” and it will be used as a technique to save the lives of millions of newborns.

By MartaFF (http://www.lainfertilidad.com) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

                 The main reason why scientists have even thought of creating such a method is due to defectuous mitochondrial deoxyribonucleic acid (DNA) that some women have. Since every embryo receives mitochondrial DNA only from the female parent, these women pass this DNA to their embryo. Thus, the fetus becomes vulnerable to many life-threatening diseases which can cause massive harm to vital organs such as the heart, liver, brain and central nervous system. Up till now the only fertility options for these women have been either adoption of a child or in vitro fertilization with an egg donor.

By Martin Strachoň / Wikimedia Commons.(http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Imagine what could happen if scientists can remove this faulty mitochondrial DNA and replace it with a healthy kind. The child would live! This is exactly what three-parent in vitro fertilization does. This mini transplantation process involves taking the nucleus of the mother’s egg and putting it in a female donor’s egg cell that contains healthy mitochondria. Then this egg cell is fertilized with the father’s sperm. Although the embryo does contain donor DNA apart from parent DNA, the phenotype of the embryo does not change. This method allows the baby to be healthy and live a normal life. It also gives parents the chance to have their own child who is genetically related to them.

By MyName (Imperfect chaosimperfect_chaos) (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons

                Unfortunately there are ethical issues which are delaying the incorporation of this technique in fertility laboratories. Many people debate that transplanting mitochondrial DNA into an egg can also lead the way to other possible genetic modifications that parents want to make to “improve” their children such as higher IQ, a certain type of eye color etc. This argument fails to make a strong point as to why the three-parent in vitro fertilization should not happen considering that it could save many fetus lives.

All in all, scientific discoveries have enabled a way for mitochondrial diseased fetuses to live and grow into healthy babies. Check out this short video which sums up the way the procedure is performed and the benefits of this method.

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Credit: NMANewsDirect

By Doris Stratoberdha