The sarcomere is the smallest contractile unit in our muscles. Through the sarcomere two proteins, actin and myosin, run through alternating in parallel. When a muscle contracts, small strucutres known as myosin heads, attach themselves to the binding site of the actin whereby it is pulled towards the center of the sarcomere making it shorter (contracted). Although one might intuitively think that ATP is needed to pull the sarcomere to the center, in this process ATP is needed to detach the myosin from the actin therby relaxing the sarcomere and muscle. Although, for the muscle to relax it previously has to be contracted- Therefore contracting muscles still inderectly causes the use of ATP.
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The NHS has formed collaboration with Google's artificial intelligence tool DeepMind. This software was originally introduced to monitor kidney disease in patients. However this article reveals that google would have complete access to health data of 1.6 million NHS patients, including diagnosis for HIV positive, abortions and drug overdose. Although google is obliged to keep this data confidential, it is concerning that an additional and so powerful party should posses so much patient information. However in this and other articles it was argued that through this artificial intelligence the more tedious work of doctors, such as paper work could be facilitated and reduced. This would be highly beneficial since then doctors could stay more alert and dedicate more time to treating their patients. Furthermore it argued that the data could be used to provide representative statistics to doctors when diagnosing their patients which, could prevent deaths.
It is a very interesting article, which really makes one think if such an approach to clinical practice is appropriate or not. If the IA could offer the benefits that it claims, that would be great. But a abuse of the data would be fatal. https://www.newscientist.com/article/2086454-revealed-google-ai-has-access-to-huge-haul-of-nhs-patient-data/
https://www.theguardian.com/society/2016/apr/01/female-doctors-new-contract-medical-royal-colleges
Lung Cancer
Lung cancer belongs to the four most common cancers in the UK. In 2013 over 45000 individuals were diagnosed with lung cancer and only 5% recovered. Therefore we can see how lethal this disease is to our society. Causes The most common cause of lung cancer is smoking and is estimated to cause 85% of the cases. This is due to the toxins and carcinogens in the smoke which is then inhaled into our lungs (see more detailed information of how smoking is linked to lung cancer in the 18/11/15 blog entry). Furthermore lung cancer can also develop in people who are often exposed to smoke and therefore “smoke passively”. Studies have showed that there is a increased 25% chance of cancer development in people who live with smokers. Carcinogens are cancer provoking substances. These can directly cause a mutation in the genes involved in controlling cell division and the cell cycle. These group of genes are known as proto-oncogenes (once these genes mutate they are known as oncogenes). If these are disrupted, cells multiply and divide uncontrollably resulting in a malignant or cancerous tumor. Randon is a naturally occurring radioactive gas which contributes to an estimated 3% of lung cancer in the UK and is often found in buildings and damages the lungs of its inhabitants. Additionally the exposure of other pollutant chemicals such as arsenic, beryllium, cadmium, coal and coke fumes, silica, nickel and asbestos, substances found in industrial areas, provoke lung cancer. Non-smokers also develop lung cancer. Is this due to the other many environmental cancer provoking factors other than cigarette smoke, or is it something else? Studies have shown that individuals both smokers and non-smokers are more likely to develop cancer when they have a relative who developed lung cancer. Emphysema Emphysema is a condition which damages the alveoli air sacs in our lungs, where gas exchange takes place. Hence, they are essential for breathing and people therefore suffer from breathing difficulties. The condition can be provoked by smoking. Other risk factors include, deficiency of alpha-1 antitrypsin enzyme, being male, age and air pollution. Smoking damages the cilia which line the respiratory tract that are responsible for mucous secretion. Furthermore, smoking provokes more mucous secretion. Hence, the ability of secretin decreases while the amount of mucous needed to be secreted increases. As a result it is very likely for there to be a bacterial infection. Even though theses symptoms can be medically treated, the inflammatory response of the immune system causes the release of destructive enzymes. This contributes to a loss of elasticity of the lungs which in turn causes ruptures and damage to the alveoli. A alpha-1 antitrypsin deficiency is linked in with this. The enzyme is a substance that fights off the destructive enzyme found in lungs called trypsin (which is most commonly actually found in the digestive system). Trypsin is a destructive enzyme released by the immune system into the lungs to destroy bacteria, as discussed broadly before. Trypsin will damage the lung tissues. If there is a lack of the antitrypsin then there will be a vicious fatal cycle where trypsin is released to destroy the bacteria but then ends up destroying the lung tissue aswell because there is no antitrypsin. So therefore what happens in emphysema is that the surface are of the alveoli where the gas exchange takes place is reduced due to their destruction leading to shortness in breath. http://www.medicinenet.com/script/main/art.asp?articlekey=53012 http://www.nhs.uk/Conditions/Cancer-of-the-lung/Pages/Prevention.aspx http://www.emedicinehealth.com/emphysema/article_em.htm#what_causes_emphysema http://www.webmd.com/lung/copd/what-is-emphysema Celiac disease is a chronic autoimmune disease where the ingestion of gluten by the person is not possible due to the adverse effect on the small intestine and inability of digestion.
Celiac disease is caused by an autoimmune response by the immune system. Meaning that the immune system wrongfully attacks a healty tissue when another component is targeted. This occurs when it detects the gluten protein in the body. By responding with an attack on the protein it unintentionally damages the small intestine as well. The body detects gluten as a threat even though it is non-harmful substance. Symptoms and negative health consequences of celiac disease include: diarrhoea, bloating, abdominal pain, weight loss, fatigue (as a result of malnutrition), lactose intolerance, central and peripheral nervous system disorders, gall bladder malfunctions, etc. Nutritional deficiencies of iron, minerals and vitamins are also related symptoms. As mentioned the body’s immune response to “attack” the gluten unintentionally damages the small intestine. It specifically damages the villi of the small intestine, small projections which increase the surface area for nutrient absorption. This is known as villous atrophy. Since the surface area of absorption is decreased the body can no longer absorb nutrients as efficiently. This explains the reasons of the symptoms related to the disease. There is a lack of absorption of nutrients such as vitamin A, D, E and K- all of which are essential to our metabolism. Therefore the body is malnourished, leading to fatigue due to the lack of energy from the unabsorbed foodstuffs. Due to the lack of being able to digest gluten patients experience bloating and diarrhea. Lactose intolerance arises through the lowered productivity level of lactase production as well as the reduced absorption surface. Gall bladder malfunction and other symptoms also arise due to the reduced production of enzymes and hormones, which are usually produced in healthy small intestines. In the case of gall bladder malfunction it is due to the lack of the hormone responsible for gall bladder contraction, CCK (cholecystokinin), which is produced in the duodenum. Celiac disease is genetic and therefore inheritable. In the UK it affects 1 in 100 people. It is caused by the genetic mutation of specific genes known as HLA-DQ genes. These genes are responsible for the development of the immune system which distinguish cells between self and non-self. These genes are located on the sixths chromosome. Depending on which variations of alleles an individual inherits, the risk of developing celiac disease will increase. Celiac disease can be diagnosed by a blood test in which the levels of the antibodies that act against gluten are tested for. People with a higher level of these specific antibodies will have celiac disease. An upper endoscopy may as well be carried out as a diagnostic method. In the procedure multiple biopsies are taken from along the duodenum and jejunum to be examined- since at simple eyesight a damage cannot always be established. Pathological changes categorized by the Marsh Classification can indicate the presence of celiac disease. Marsh Stage 0: Normal mucosa. Marsh Stage 1:Increased number of intraepithelial lymphocytes. Marsh Stage 2: Proliferation of the crypts of Lieberkhün. Marsh Stage 3: Partial or complete villous atrophy. Marsh Stage 4: Hypoplasia of small intestine. Occlusion of Coronary Arteries
As any other cell in the body, cardiac muscle cells require a supply of oxygen and nutrients via the blood. The coronary arteries are those which surround the heart and supply it with blood. When an individual suffers from a occlusion of a coronary artery, what this essentially means is that the artery is subject to partial or complete blockage. This is also known as coronary artery disease. These blockages are caused by another condition known as atherosclerosis, which involves the buildup of plaques in the arteries. Plaque is made up of fat, cholesterol and other substances. The deposit and solidification of plaque causes the blood vessels to narrow. This inhibits blood from passing through effectively. Furthermore atherosclerosis promotes the formation of blood clots. The ability for our blood to clot is essential for our survival since we would otherwise all be exposed to the same threats as hemophiliacs. However these blood clots do not always dissolve in the arteries and can cause a blockage. Both of these are contributing factors to coronary artery occlusion. As a result of the blood not being able to pass through the vessels effectively due to the more narrow space, patients suffer of chest pain (angina) , shortness of breath and in more unfortunate cases heart attacks can arise. The patient experiences pain as of a result of the heart’s overworking to account for the inefficiency (arrhythmia). There are certain risk factors which increase the chances of developing coronary artery disease. These include smoking, family history of the disease, high blood pressure, high levels of low density lipoprotein and and low levels of high density lipoprotein (cholesterol), taking birth control pills, diabetes and obesity. How and whether lipids contribute is unsure and currently a debate. However these should be avoided in order to avoid being overweight or obese which is a risk factor. Partial occlusion may be treated by medication which can cause the artery to expand, prevent the heart rate to increase, relax the muscle in the coronary artery thereby increasing the blood flow in the artery. Alternatively surgery can aswell be performed. While browsing youtube videos I came across a transplant surgery- A double hand surgery. I was surprised that surgeons are able to do this and that it works so effectively. I therefore decided to look into the procedure. Like in any transplant it important that the donor shares the same blood type as the recipient, as otherwise the recipients body will detect the new hand as alien and definitely reject it. Nevertheless, even when they both do have the same blood group, the patient will always be given immunosuppressive drugs. These weaken the immune systems response when it detects the foreign limb, preventing it from rejecting it. However these drugs which have to be taken continuously after the surgery have many side effect which the patient will have to cope with he rest of their lives. These side effects include fatigue, fever to chills and frequent urination. Any person taking immunosuppressants will inevitably as well be more prone to infection. The transplant and amputation is usually positioned below the elbow and the blood flow in the arms is restricted. The hand is connected to the arm i the order bone (ulna and radius), tendons, nerves, arteries, veins and skin. In this video the patient shows incredible results. The first double hand transplant was carried out in the UK this year shortly after the NHS having launched their new hand transplant earlier in the year. The patient has had successful results after the extensive and complicated 12h surgery it does not necessarily guarantee a successful ending for the patients. Although after surgery patients gain functioning mobile hands and sometimes even some sensation, the psychological impact is often too much for the patients to cope with. The first patient to receive a hand transplant got the removed in a secret operation 3 years after receiving them. This reaction is without any doubt understandable, especially since our hands are constantly visible to us and remind the patient constantly that they are not their (a situation which one wouldn't experience when receiving an organ transplant). When thinking about the use of our hands these phycological reactions make even more sense. “For someone to use someone else’s hands to hold his wife, his kids - it is not easy,”1. After reading this article and watching the video, not only did i learn about a surgery which I find remarkable but it also made me think and come to a conclusion. When we preform a surgery or a procedure we can't only have the person's medical interests in mind but also patient's personal and phycological necessities and attachments. Only when we attempt to take into account all possible factors and start treating the human being in front of us instead of a mere patient and instead as a person, will we be able to reach their maximum potential well being. References:
1. https://www.theguardian.com/science/2016/jul/22/double-hand-transplant-it-is-a-small-miracle-looking-at-what-nature-has-allowed-us-to-do. 2. https://en.wikipedia.org/wiki/Hand_transplantation. 3. http://www.healthline.com/health/immunosuppressant-drugs#SideEffects6 4. https://www.youtube.com/watch?v=pUdfi5MALwg
We are currently studying evolution in our biology class. Even though one wouldn't directly relate this topic to medicine, when practicing medicine knowing the evolutionary process behind the human body may facilitate and support our decisions when making a diagnosis or carrying out a procedure. Regarding this topic I came across an article in the new scientist titled ‘ Darwinian medicine: Does intensive care kill or cure?
Darwinian or also known as evolutionary medicine only in the past decade has become popular but is definitely still not a part of mainstream medicine. The philosophy behind this practice is to find out what evolutionary changes and traits have caused the patient's condition. Doctors don't only focus on thinking on how to cure the person given the symptoms, but rather go a step further and think about how the disease or condition evolved in the patient in order to then carry out a more appropriate response and procedure. Darwinian medicine doesn’t immediately or necessarily direct a symptom as an issue. It allows us to see the bodies responses of our body as a natural defense rather than a problem. For instance a fever. As soon as we get a low fever at around 38° we tend to immediately take paracetamol or ibuprofen to bring our temperature down. What many people fail to realize that a fever is a natural defence of our body to get rid of intrusive microorganisms in our bodies, by raising our body temperature we are trying to kill microorganisms such as bacteria. A premature intervention to a favere will hinder our body from protecting us from these harmful intruders. In the particular article that I read Mervyn Singer, director of the Bloomsbury Institute Center for Intensive Care Medicine at University College London suggests that we should pay more attention to evolutionary medicine. He says that in the past 10 years none of the advancements in intensive care have proven to improve patient recovery rates. He specifically refers to the case of systemic inflammatory response syndrome (SIRS) which patients in trauma tend to undergo. In this period, known as sepsis, stress hormones are secreted and the patient’s temperature and heart rate tend to go up. If the patient does not return to equilibrium then organs will start to malfunction. This is one of the leading causes death causes in intensive care. According to the accepted theory during trauma the necessary oxygen levels fail to reach the organs and cells die causing organ failure. Singer disagrees with this statement since there is evidence that shows that the organs in patients who died of organ failure had fairly normal oxygen levels. He has made a different interpretation of why it is that organs fail and lead to patient death. He states that during trauma our body goes into “fight mode” in which many chemicals and hormones are secreted by our bodies that modulate our immune response. As a consequence metabolism slows down because these same chemicals damage the mitochondria (the organelles in our cells responsible for energy production). Since the cells can’t keep up with its regular activity rate with less mitochondria it goes into a dormant mode since otherwise it would die. Singer interprets organ failure as a temporary response of our body while it focuses on fighting with our immune system whatever is intervening in our body as a last resource. Once a patient recovers this phase, the mitochondria will have to be re-established, which when taking antibiotics and sedatives can often be prevented by. In conclusion Singer states that our bodies are not adapted to have multiple tubes and monitors attached to ourselves in order to recover from trauma. Therefore this is another prime example which shows how important it is to understand why the body responds a certain way due to its evolution. The mode in which our bodies go into during trauma, is clearly a result of evolution which our ancestors developed in order to survive. Before intervening we have to understand the course of action that our body will take to ensure a positive outcome. After listening to Singer’s many physicians agree that we should starts thinking more broadly and approaching problems in new angles while others, even though they were amused by the idea, were not fully convinced. The article then goes on saying that evolutionary medicine suggests what we should think about and what studies we should do. I think evolutionary medicine is very important since it could stop or motivate us from making one decision over another. If a doctor is not aware of why our bodies suffer certain symptoms and what, if any, their purpose is, then he/she won't be able to make a decision as appropriate as if when he/she did. This topic has actually surprised me on how interesting it is. And i must honestly say that when I become a doctor I will like to be able to introduce and involve darwinian medicine in my years of practice.
https://www.newscientist.com/article/mg20727731-600-darwinian-medicine-does-intensive-care-kill-or-cure/
How Have CT Scans helped Us Understand The Evolution Of Snakes?Computerized Thomography (CT) uses X-rays in order to produce detailed images of the inside of a body. Many images are taken along 360 degrees and put together to obtain a final 3D model. This technique allows an image to be created without having to invade the body. This is very useful when analyzing fossils since they can't be opened or manipulated. A 90 million year old fossil is giving scientist new indications on when snakes may have evolved to loose their limbs. Previous suggestions stated that snakes lost their limbs when they migrated to the sea to become aquatic animals. Using CT scans, an 3D model of the inner ear of the fossilized specie, the Dinilysia patagonica a close relative to the modern snake, was made. The model of the skull showed a similar structure to those of snakes who currently burrow. This therefore suggests that snakes started evolving on land and not in the sea. Due to this newly found fossil, geoscientist at the University of Edinburgh believe that snakes lost their limbs when they migrated to burrows in order to be more mobile to hunt in this environment. I find that this hypothesis is quite interesting and unexpected. On a first thought, it wouldn't have occurred to me that a structure such as the interior structure of the ear of an organism would give us information on the evolution of the limbs of that same specie. Therefore I was pleasantly surprised by this idea. Bibliography:
1.http://www.wired.co.uk/news/archive/2015-11/27/how-snakes-lost-their-legs 2.https://www.sciencedaily.com/releases/2015/11/151127195113.htm 3.http://www.amnh.org/explore/news-blogs/research-posts/reptile-fossil-solves-mystery-of-how-snakes-lost-their-legs/ 4.http://www.nhs.uk/Conditions/CT-scan/Pages/Introduction.aspx What is Somatic Cell Nuclear Transfer? Somatic cell nuclear transfer involves taking the nucleus of a somatic cell of one individual (which is any diploid cell, therefore not a sperm or ovum cell) and using it to replace the nucleus of an unfertilized egg of another individual. To do this one first has to obtain the two different cell types needed for the transfer. These are then fused together using an electricity pulse. The artificially fused egg will then continue to divide as if it had been fertilized. Therefore a zygote starts to form, eventually it will reach a stage at which one can extract its stem cells from. This technique is therefore interesting for medical research involved with embryonic stem cell research, as it is a promising and quickly advancing area for regenerative medicine. We refer to this purpose of the technique as therapeutic cloning. Embryonic stem cells, are very useful in medicine since they are unspecialized cell, they are totipotent. This means that they can potentially divide into any cell and an endless amount of times. But there are a set of pros and cons regarding the creation and use of embryonic stem cells: Pros Using embryonic stem cells can be used to save and improve thousand of patient’s lives. For example using stem cells researchers were able to treat people who suffered from Stargardt’s Disease, which due to a mutation causes the membrane protein used for active transport in retina cells to malfunction, this eventually causes loss of sight. With the use of stem cells doctors have been able to treat these people successfully such that they retained vision and no tumors were formed. Cons There is a set of ethical issues involved with using and artificially creating embryonic stem cells. The ethical issues involved are similar to those with abortion. Embryonic cell could, if not used for medical treatment or research, become potential living beings. There is also a risk of tumor development as stem cells can divide unlimitedly. Another use of the application of this technique is to actually fully clone an organism. The most famous case of this type of cloning was the creation of Dolly the sheep. The procedure is the same as that for therapeutic cloning, only that the ovum is inserted into the womb of a surrogate mother and left to fully develop into a fetus. The following image clearly shows you how the process is carried out. There are a lot of skeptics regarding fully cloning a living being, especially if it should ever come to cloning a human. Lots of people feel that it stepping a step to far and that by selectively cloning people we are playing God. Personally I do not agree with the fact that there is an issue with God as I do not believe in that divine figures, but I do agree that in a sense we are taking a step to far because we are playing with nature. Who we genetically become is determined by which egg and sperm fertilize together. If we interfere with this then one might argue that cloned being are unnatural. Also, by genetically selecting and modifying our offspring, we would reduce and unbalance the human genetic pool.
Another negative aspect with cloning are not only the ethics, but also the fact that it is a big step in the unknown. This would be a big step in human evolution and we don’t have any information to know the possible dangerous consequences involved with it. |
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