Exercise keeps brain connections alive

Casaletto K et al. Late‐life physical activity relates to brain tissue synaptic integrity markers in older adults. Alzheimer’s & Dementia, January 2022.

Physical activity has myriad benefits, including enhancement of cardiovascular health, lowering blood pressure, and promoting mental health. A recent study showed that when older adults stay physically active, their brains are activated to produce more of a protein type that enhances the connections between neurons to maintain healthy cognition. The beneficial effects of physical activity on cognition have been shown in many times in laboratory animals but it has been much harder to demonstrate in people. Neurons are separated from each other by tiny clefts known as synapses. Nerve signals that travel along the nerve cells must cross these gaps for the information to reach its destination. Synaptic proteins located at the vicinity of synapses are tasked to provide the chemical mechanism whereby information is transmitted and link the neurons into cognitive networks. In this study, the late-life physical activity of 404 elderly people, who agreed to donate their brains when they died, have been tracked through annual actigraphy monitoring. Next, their postmortem brain tissue has been analyzed for the levels of key synaptic proteins. Strikingly, elderly people who remained active had higher levels of synaptic proteins that are known to facilitate the exchange of information between neurons.

Researchers also found that increased synaptic proteins were not limited to specific cognitive-related brain regions; physical activity seemed to exert a global effect on brain connectivity beyond the parts of brain that are directly involved in cognition. Maintaining the integrity of these connections between neurons may be a key protection for the age-related cognitive disorders such as dementia and Alzheimer’s. Physical activity is a readily available medicine that can boost our cognitive and mental health, free of charge and with no prescription. This study emphasizes one more time that we should continue being physically active, particularly as we age.

Oxygen production by microbes without sunlight

Kraft B et al. Oxygen and nitrogen production by an ammonia-oxidizing archaeon. Science, January 2022.

Oxygen is vital for life on Earth. Most oxygen on land and in the sea is produced

as a result of photosynthesis, a process in plants, algae, and cyanobacteria that requires sunlight. Now a research team made a surprising discovery that some deep-sea microbes are also tasked to produce oxygen but in a completely different way. By investigating these microbes which live deep in the darkness, the researchers have focused on a microbe named Nitrosopumilus maritimus, which was previously found out to be converting ammonia to produce nitrogen by using oxygen. The team decided to observe these microbe cultures in airtight containers that are kept in the dark to mimic the deep ocean conditions. They have found that these cultures first used up all the oxygen in the water, and then to everyone’s surprise, within minutes, oxygen levels started increasing again. At first glance, they seem to produce just enough oxygen for them to survive and scientists thought that these low levels may not possibly be enough to influence oxygen levels on earth. However, when this effect is considered at a global scale, it is conceivable that the oxygen produced by Nitrosopumilus maritimus can be quickly taken by other nearby organisms. This means that this microbe is ultimately contributing to overall oxygen levels in oceans, if not for the whole atmosphere. The exact mechanism of how these archaea bacteria can produce oxygen without light is not known and it has been now the focus of future research efforts. This study opens up the possibility that there may be many different deep sea species with a whole different metabolism functioning. It also emphasizes the importance of studying and protecting the deep oceans.

70 mysterious rogue planets discovered

Miret-Roig N et al. A rich population of free-floating planets in the Upper Scorpius young stellar association. Nature Astronomy, December 2021.

Rogue planets are the freely floating cosmic objects in our solar system that roam the universe on their own without orbiting a host star. Scientists knew very little about these planets until now. A team of astronomers using data from several telescopes worldwide identified at least 70 rogue planets in the Milky Way. Since rogue planets are not illuminated by a nearby star, they used to be almost impossible to capture and image. After few million years of their formation, these planets are still hot enough to glow and become detectable by extra sensitive cameras in large telescopes. After extensive analyses of all the data they could gather revealed at least 70 rogue planets and up to 170 candidate planets that are close to a star-forming region near the Sun, located within the Scorpius and Ophiuchus constellations and 420 light-years from Earth. These findings suggest that there could be many more of these planets roaming the galaxy. Rogue planets could have been either formed from a cloud of gas and dust – the same way stars do – or they could have once been a part of a star system before getting ejected. The team hopes that by studying the large group of rogue planets, they will be able to identify their origins and how they formed and evolved. New developments in space-watching technology are very encouraging for astronomers, as they hope that by studying this large group of rogue planets, they will be able to understand their origins and ultimate fates.

Athlete’s foot is a frequent infection that millions of people suffer from annually. I once had it during my military service where we had to wear boots almost an entire day. Once during a noon intercession, I performed my ablutions to pray and I placed my feet under the sunlight to dry them. I was also hoping that ultraviolet rays from the sun would be good for the infection. Soon, flies swarmed in between my toes. When I could not bear the excessive itching, I tried to kill the flies until I was stopped by a friend who reminded me of the great sage Bediuzzaman’s comments where he called flies “cleaning workers.” At that time, I also remembered Prophet Muhammad’s (peace be upon him) words on flies. So, I patiently endured the nuisance, and repeated the same procedure for the next three or four days. Eventually, my feet were healed and there was no trace of the fungi.

In one of his very interesting hadiths, the Prophet, peace and blessings be upon him, is reported to have said the following about flies: “If a fly falls into your drink, dip it into your drink, then throw it away, for on one of its wings is a disease, and on the other is a cure. It dips the wing with the disease to protect itself” [1]. This hadith has been a reason for much controversy mainly due to germ disease theory.  According to Jonathan C. Brown, “even before modern medicine, the Hadith of the Fly was raising skeptical eyebrows and prompting Sunni defensiveness as early as the writings of Ibn Qutayba (d. 276/889)” [2]. Brown also mentions that this hadith “could be false or it could be true, since scientists used the flesh of a snake to help prepare antidotes to its poison” [3].

Before the microscope was invented it was impossible to define microbes or talk about the anatomy or microbiology of flies as we can today. However, the introduction of experimentation and observation as an important scientific method with the Renaissance served as a turning point in Western scientific revolution. Thus, the “proof-based medicine” conception that relies on experimentation and observation emerged as a precursor to today’s medicinal and scientific research. The importance of perceptions that rely on causes relating to the material world in persuading the human mind cannot be denied. It is harder to make people believe in something unless they are provided with concrete results that appeal to our five senses. We should not rush to deny any claim solely based upon our preconceptions and prior knowledge without doing any research about it; rather, we should pass our judgment on it after experimentation and observation.

Some people may automatically reject the idea that when a fly falls in our food or drink that we should immerse this microbe-carrying insect completely and they may say that this would not eliminate the microbes. Indeed, it may sound reasonable to assume that this disgusting insect that feeds on all sorts of dirt would cause only diseases. If you have an ample supply of food or water and if you do not have the stomach for it, you can of course refrain from eating or drinking such a food or drink. But, you can hardly advise someone who has very little water or food in a desert or at the time of famine to throw away what they have because of a fly.

We should examine different types of flies in laboratory settings using the method of experimentation and observation. First of all, it is very difficult to prove that someone can contract an illness from eating food in which a fly had fallen into although he or she had immersed that fly completely in that food. If it is proven that someone becomes ill due to a fly’s alighting in their food, then strong objections can be raised. If it is said that there many diseases caused by flies, no one will deny it. The point is not whether flies carry germs, but whether this advice for being protected from the germs carried by flies is correct or not. As a matter of fact, the advice by the Prophet seeks to protect us from diseases that may be caused by germs carried by flies. The great scholar Bediuzzaman’s words on flies also give us an alternative perspective to consider about these “tiny birds”:

“…Flies are dutiful about cleaning away noxious substances or germs that cause disease. By sucking up and absorbing harmful germs, they destroy them, and they cause noxious or poisonous substances to change into other harmless forms, thus preventing the spread of many contagious diseases. A sign that they are both laborers for health and cleansing operatives and chemists, serving many instances of wisdom, is the fact that they exist in extremely great numbers. For the things that are valuable and beneficial are multiplied.” [4]

The hadith of the Prophet and Bediuzzaman’s commentary encourage us to explore more about flies and whether they can be a source of healing in any way.

Flies are very ubiquitous on earth. There are approximately 125,000 species of flies, but only ten species live in our homes and are of concern to us. They feed on garbage and organic waste materials that act as a breeding ground for microbes such as bacteria, fungi, and viruses. The female fly lays down more than 100 eggs in the dung of some animals or in garbage. After one day, the larva emerges to feed on the surrounding organic materials. In two weeks, they become full-grown flies. In four generations, one female fly can lay 1.5 million eggs, but fortunately the majority die due to weather circumstances or become food for birds, reptiles, amphibians, and other insects. A fly can live for 60 days at most.

Given the ecological balance in nature, one comes to accept that there should be species that will remove all sorts of organic waste, garbage, dead animals or plants, and similar things by eating them. Houseflies feed on the rotting corpses of animals while female horseflies suck blood. How can flies, which act as health workers that are charged with the duty of cleaning the world, digest so many diverse amounts of garbage and waste?

Flies get their nourishment differently from other animals. What other animals do for digestion is done by flies outside their bodies. They do not have teeth-like structures in their mouths in order to chew solid, dry food and therefore have to turn such food into liquid form or split it into 0.45-mm or smaller pieces. In this liquid form, flies can easily suck up their food using their suitably shaped mouths. To do this, flies vomit a saliva-like liquid, containing enzymes and acids, and that disintegrates the solid food into something that can easily be digested in a couple of seconds. In this process, some of the microbes in that waste food can be disintegrated while the rest will be sent to the stomach.

These foods and microbes taken inside in the form of vomit are sent to a sac called a “crop” if they are not small enough to go through the digestive tract. Flies produce fresh saliva regularly during which the vomit moves between their mouths and crops. Eventually, the sufficiently liquefied food is sent to the stomach which contains enzymes and acidic content as well as partially disintegrated microorganisms.

What does scientific research tell us?

Based on the theory that flies must have remarkable antimicrobial defenses and resistance to survive the bacteria from rotting dung, meat, and fruit, a team at the department of biological sciences at Macquarie University in Australia set out to identify those antibacterial properties.

“Our research is a small part of a global research effort for new antibiotics, but we are looking where we believe no one has looked before,” said Joanne Clarke, who presented the group’s findings at the Australian Society for Microbiology Conference in Melbourne.

Clarke’s research showed that flies produce their own antibiotics, and this was tested on four different fly species. Such research may lead to better treatments for human infections from Escherichia coli and other virulent bacteria even, perhaps, Staphylococcus aureus (MRSA).

Upon preliminary results, a global pharmaceutical company decided to support the research over the next six months by trying to isolate antibiotic compounds from the material collected from the flies. The research team is trying to identify the specific antibacterial compounds. As antibiotics that will eventually be invented and chemically synthesized come from the body surface of flies, not from other fungi or bacteria, it is believed that any gene that gives resistance to microbes will not be easily transferred to pathogens and the new antibiotic form will have longer and more effective treatment duration [5].

Later, Russian doctors had developed interest in this topic and observed that flies contain many substances that can be more effective than traditional medications and certain fly larvae have very strong therapeutic effects [6].

Noting that flies should be kept away from hospitals, Professor Juan Alvarez Bravo at the University of Tokyo expressed his support for such research, saying, “But soon we will witness a rapid treatment for many diseases, which consists of extracts from flies” [7].

Some researchers at Auburn University of the United States discovered a protein in the fly’s saliva which can accelerate the lengthy process of healing wounds and chronic skin cracking. Entomologists Ed and Mary Cupp managed to isolate the protein which houseflies inject into their prey to increase blood flow in the skin of their prey. Mary Cupp and surgeon Steven Swaim demonstrated that surgical incisions, skin ulceration, and diabetic foot lesions treated with solutions that combine antibiotics and this protein heal faster and stronger than incisions treated with antibiotics alone [8, 9].

In another study, it was found that epithelial cells forming the inner layers of the front and back intestines of the fly protect it from the bacteria it swallows thanks to a special cuticular lining, and in this way, bacteria never directly touch the intestinal epithelium and cannot give any damage to it. In this study, it was noted that people nurtured a radical approach to flies and that fly control has been abused for the sake of human health, suggesting that flies may be the source of novel germicides that make use of their antimicrobial digestive enzymes, lysozyme, and antimicrobial peptides [10].

Viruses cause many diseases in cattle, sheep, and birds. These diseases include encephalitis, aphthous fever (foot and mouth diseases), and duck plague which can be transferred to people through infected animals. Some crops such as potatoes, tomatoes, bananas, and sugarcane can also be destroyed by viral infections.

Flies carry the viruses of many diseases which are consequently transferred to man’s food, drink, and body. Of these viral diseases are common flu, measles, mumps, chickenpox, warts, yellow fever, infectious liver diseases, some cases of paralysis, some types of cancer, and some chronic diseases of the central nervous system.

El-Naggar, Zaghloul, from Egypt, indicates that some of the disease-causing viruses may directly infect living beings and cause damage to their cells, while there is a type of virus which infects bacteria cells known as “bacteriophage.” These viruses, which can kill the bacteria they infect in a short time, are known as “virulent bacteriophage.” Those viruses that do not kill the bacteria they infect are called “temperate bacteriophage” [11].

After a bacteriophage infects a bacterium, more than 100 viruses are released from that bacterium and each of these viruses can infect new bacteria. The spreading of infection may continue until all vulnerable bacteria cells die. After it was discovered that bacteriophages are parasites of bacteria, they started to be used in treating the diseases caused by bacteria. However, their use in this manner declined after the discovery of antibiotics. Yet, the interest in phage treatment was revived after the emergence of bacterial resistance to antibiotics [12].

Researchers from Stanford University announced that they found a substance in flies that can improve the human immune system [13].

The work by Rehab Mohammed Atta from the Microbiology and Immunology Department, National Research Center, Cairo, Egypt, is quite remarkable [14]. In this research, the extracts taken separately from the left and right wings of flies were used against the bacteria and fungi calculated on nutrient “agar” media in the laboratory. It was demonstrated there was both bacterial and fungal growth for the left wing extract plates while no bacterial or fungal growth was reported for the right ones.

Given the fact that the garbage and rotting corpses on which flies feed from contain numerous dangerous bacteria, it is quite reasonable that it contains antibacterial materials necessary for its survival. In this case, the fly’s needs might be of service as sources of antibiotics that can prevent epidemics among human beings, and this may be the reason why they were created in the first place: not to be a source of nuisance but a source of healing for us.

Aj-Taili, et al., from the department of medical microbiology, Qassim University in Saudi Arabia, conducted an experiment using water, honey, and various fruit juices in different cups. They found no germ in the solution in which the whole body of fly was immersed while the solution in which only one wing of the fly was dipped indicated the presence of germs [15].

In sum, we can say that antibacterial materials produced in the bodies of flies protect them against the microbes in their environments and that these microbes can prevent epidemics among human beings. At the very least, this topic deserves in-depth research. Atta’s study confirms the virtue of the hadith that says, “The best way to release this vital antidote is to dip the fly in a liquid because these substances are concentrated on the outer surface of the fly body and wing.” Abduldaem al-Kaheel refers to this study in his website: “This is logical because the fly has a lot of harmful bacteria on the outside of her body and therefore in order to continue in her life, it should also carry anti-bacterial materials; these materials were furnished by God to protect it from viruses and diseases.” In the light of these studies, the need for conducting more research for obtaining antibiotics from the right wing of the fly is clear [16].

References

1. Abu Dawud, At’imah, 49. Also see Bukhari, Tib, 57, Bed’u al-Khalk 17; Ibn Majah, Tib, 31, Nasa’i, Far’, 11.
2. Brown, Jonathan A. C. 2009. Hadith: Muhammad’s Legacy in the Medieval and Modern World, p. 264.
3. Ibid. p. 255.
4. Nursi, Bediuzzaman Said. 2008. The Gleams. The Light, Inc. p. 376.
5. Danny Kingsley, ABC Science Online, 1 October 2002, The new buzz on antibiotics. Clarke, J., Gillings, M. and Beattie, A. (2002). Hypothesis-driven drug discovery. Microbiology Australia, pp. 8–10.
6. Petersburg State University, (2006). The fly effect: Russian Scientists Invent new medicine with the help of flies.
7. Bravo, J. A. (1994). The ointment in the fly: antibiotics. New antibiotic derived from a common fly. The Economist (US).
8. Ed and Mary Cupp (2005). Protein in Fly Saliva Speeds Healing of Incisions Wounds. Auburn University. R Am Ex Ars Medica, Inc., 7:23.
9. Protein in Fly Saliva Speeds Healing of Incisions, Wounds 20-Jan-2005. www.newswise.com/articles/protein-in-fly-saliva-speeds-healing-of-incisions-wounds
10. Nayduch, D. and Burrus, R.G. (2017). Flourishing in Filth: House Fly–Microbe Interactions Across Life History. Special Collection: Filth Fly–Microbe Interactions. Annals of the Entomological Society of America, 2017, Vol. 110, No. 1.
11. El-Naggar, Zaghloul, (2010). Housefly Falls into One’s Drink! 09 September 2010. www.quranandscience.com/quran-science/sunnah-science/204-housefly-falls-into-ones-drink-274
12. Aydogan, D.Y., Hadimli, H.H. (2016). Bakteriyofaj Tedavisi (Bacteriophage Treatment), Etlik Vet. Mikrobiyol. Derg.; 27 (1): 38–47.
13. Stanford University Medical Center, 2007. Fruit Fly Insight Could Lead to New Vaccines. Science Daily. www.sciencedaily.com/releases/2007/03/070308220904.htm
14. Atta, R. M. (2014): Microbiological Studies on Fly Wings (Musca domestica) Where Disease and Treat. World Journal of Medical Sciences 11 (4): 486–489.
15. Aj-Taili, S.I., A.A.R. Al-Misnid and K.D. Al-Uteybi, (2002). Wing One and the Other Disease Carrying the Cure. Qassim University. Danny Kingsley.
16. Abduldaem al-Kaheel, 1995. New facts: fly have a cure, www.kaheel7.com/eng.

We eat, sleep, and go to the bathroom. Yet, we never think about how all these physical needs are processed in the systems of our body when they are functioning normally.

Yes, our bodies are created with perfect systems by which our all kinds of needs are met. The digestive system is one of them. Our intestines are key elements of this system, so much so that asking someone “How are your intestines?” would be as comprehensive as asking “How are you?”

Digestive system

Food is critical to life. A human being can bear hunger for one month at most and can only endure a few days of drought. Thus, eating and drinking is crucial.

Foods as we eat them are not convenient for use by the cells. Food must be broken down into smaller pieces. This process begins in the mouth and ends at the anus, and it is called digestion.

The main task of our stomach and intestines is digestion. The teeth, salivary glands, the tongue, and the gullet – as well as swallowing – are essential secondary elements. Additionally, if the pancreas or liver fall ill, it can paralyze the whole system. While also working with the circulatory system, kidneys have the task of reabsorbing useful substances like glucose, amino acids, and water.

Our digestive system works together with the urinary system and the digestive organs like a factory. How these parts work together is still not fully understood, but more detailed research has been performed and revealed more secrets of the digestive system. By means of every discovery, it is realized that this perfect creation has a more intricate structure than is known.

The brain in the intestine

There are more neurons in our intestines than in our spinal cord and the intestines are created in a way that can move independently from the central nervous system. They have their own nervous system, known as enteric nervous system (ENS), which is also called the “second brain. “Within those yards of tubing lies a complex web of microcircuitry driven by more neurotransmitters and neuromodulators than can be found anywhere else in the peripheral nervous system. These allow the ENS to perform many of its tasks in the absence of central nervous system (CNS) control…” [1]. Thus, “… isolated segments of intestine can independently coordinate propulsive movements and propel content without any neural connections to the brain or spinal cord [2].

The intestines take action when food comes into the stomach. This movement is known as colonic migrating motor complexes (CMMC), and it moves the substances that cannot be digested, like bone and fiber. According to neurophysiologist Nick Spencer et al, “The gut wall contains a complete network of intrinsic nerves capable of propelling contents along the bowel, without any requirement of nerves originating in the brain or spinal cord” [3].

Eat different types of food

70% of our immune system cells are in our intestines. A big part of the approximately 38 trillion bacteria in our body are in our intestines, and they are useful; they have a big role in digesting food. Different groups of bacteria feed on different types of food; so for intestinal flora it is very important to have a variety of food on our table. For the ideal day on a plate Dr. Megan Rossi recommends people should “aim for at least 30 different plant species per week.” “The reason for this is that each plant contains different types of fibres and phytochemicals (the super healthy components of plants) that feed different good bacteria. The more plant variety, the more variety of gut bacteria – which is associated with health and happiness” [4].

Pets in our body

For Dr. Megan Rossi, “microbes are like our pets, so you have to take care of them and feed them” [5].

Of course, germ flora in our body is not just limited to the ones in the intestines. Bacteria, viruses, and fungi in our body are nearly scattered throughout the whole body. These living things produce pellicle on our head skin, irritate the gaps between our toes, live on our skin, are on duty among our teeth, and have ecosystems and assigned positions convenient to them. According to the situation, they keep their living spaces healthy or unhealthy. Although they number 50 trillion, they are approximately 200 grams of our body weight.  

Useful microbes

An average size human adult houses about 10¹² bacteria on the skin, 10¹⁰ in the mouth, and 10¹⁴ in the gastrointestinal tract [6].

These microorganisms are useful microbes with duties in our body. The harmless flora of microbes is generally present on the skin, mouth, teeth, nose, throat, and bowel and genital areas. There isn’t normal flora in internal organs except the large bowel. Internal organs have no microbes. If we look closely, flora is inserted in every part of our body which is dirty and has contact with the outer environment. If it was not for the useful flora, microorganisms causing illness would settle instead. Only intestinal bacteria are permanent microbes which are useful. For example, vitamin K plays a part in a crucial event like blood clotting and is produced in the intestine.

Control your stress

Research has revealed that mental and psychological stress affects the health of the intestines. Serotonin is produced automatically in case of need, and 85% of it is produced in the digestive tract. Stress suppresses the level of serotonin produced. Psychological illnesses are associated with low levels of serotonin.

Studies have shown that relaxing practices like meditation for 15-20 minutes can be good for health and reduce stress. At this point, daily prayers are a kind of therapy. Other ways to stay healthy include: avoiding things like alcohol and caffeine, and sleeping well.

Our body has ways of telling us when it’s not healthy. For instance, we can learn the digestive tract isn’t healthy if we have to use the toilet more than three times a day and fewer than three times a week.

References

1. Gershon, Michael D. “The Enteric Nervous System: A Second Brain.” Pdfs.semanticscholar.org.
2. Spencer et al. 2018. “Identification of a Rhythmic Firing Pattern in the Enteric Nervous System That Generates Rhythmic Electrical Activity in Smooth Muscle.” http://www.jneurosci.org/content/38/24/5507
3. http://www.flinders.edu.au/neuroscience/lab_visceral.html
4. https://www.dailymail.co.uk/femail/article-5543159/Doctor-debunks-myths-surrounding-gut-health-say-surprise-you.html
5. https://navva.org/brazil/health/why-the-bowel-is-considered-our-39-2nd-brain-39-and-other-5-amazing-facts-about-the-organ-news/
6. http://www.textbookofbacteriology.net/normalflora_3.html

One of the processes that occurs in the body is called “inflammation.” Inflammation occurs when a cut into the skin also punctures a blood vessel. This situation directly exposes the blood to the air. Inflammation occurs in a few steps. First, the blood vessels near the wound are expanded (which causes the swelling that we see near the cut) and special proteins called “fibrins” are brought in. These fibrins bind to each other to form a net-like structure. We are all quite familiar with this net, which we call a blood clot. This net stops the bleeding and cuts the interaction between the air and the blood within a few minutes.

Next, it is time to quickly eliminate any foreign objects that got into the tissue. Special immune cells called “macrophages” are sent to the crime scene to clean up. Macrophages are large white blood cells that “eat” microbes and other foreign objects using a process called “phagocytosis.” After the scene is all cleaned up, these macrophages excrete special molecules that induce tissue repair and return the blood flow to normal. An important note here is the specific order of these events. Like every single process in the body, they occur in the most purposeful way possible. What do I mean? I mean that, first the wound is closed urgently; second, macrophages are sent in; third comes the tissue repair. Any other order would have greatly lowered the effectiveness of inflammation. Imagine that the wound is closed after the macrophages are sent in. Then, by the time the macrophages killed all the microbes, twice as many would have entered the scene. The body seems to know every single event beforehand and plans its defense accordingly.

Our body is perfectly calibrated to keep our blood, the milk of our organ systems, absolutely pristine.

Let’s say a microbe managed to sneak into the blood before inflammation occurred, and is long gone to another region of the body. Does the microbe win? Unfortunately for the microbe, it has to pass another test. This time the tester is the lymphatic system. The lymphatic system is the sewage system of the body. When the blood transfers its nutrients to the tissue, the fluid goes through the “interstitial area” (the empty space between organs). During this process, some of the fluid stays in this area and starts to accumulate. This is where the lymphatic system kicks in. The lymphatic system consists of many tubes running parallel to the blood vessels and recollects any excess fluid and transports them to the subclavian vein near the neck. This way, excess fluids of the body and all of the molecules in them, are reintroduced into the circulation. If there is a problem with this process, an abnormality called “edema” occurs. Of course, the blood is a very sensitive fluid because it travels through the whole body and seeps into almost every single cell. If a microbe were to get into it, it would easily spread and cause disease. So, the lympatics first does a checkup on the body fluid. This checkup occurs at special nodes in the system called lymph nodes found all over the body. Two of the most famous lymph nodes are the spleen and the tonsils. Within these nodes are lymphocytes, special immune cells that “tag” bacteria and other microbes to be later destroyed by macrophages. Thus, the blood is continuously cleaned and kept safe from harmful microbes.

Last but certainly not the least, the final inspection the blood goes through takes place in the kidneys. The aforementioned two checkpoints prevent the entrance of any foreign materials into the blood, and the elimination of any microbes lucky enough to somehow make it through. So, the only task to be completed is the elimination of excess molecules formed in the metabolism. For example, the blood in the veins (the vessels that carry carbon dioxide formed by the respiration of cells) is carried to the lungs where the carbon dioxide is exhaled. But, a much more precise mechanism comes into play in the kidneys. Blood vessels that come from all around the body form a knot-like structure in the kidney called the “glomerulus.” This knot-like shape increases the surface area of filtration. The blood running from the glomerulus is then filtered into the “Bowman capsule,” which surrounds the glomerulus.

But wait! The sanitation system is not satisfied with this first filtration and “thinks” that the filtrate is not ready to be excreted by the urine. So, a more delicate filtration occurs right after the filtrate enters the “proximal tubule.” While passing through this tubule, essential molecules are immediately reabsorbed into the body. The most valuable of all these molecules is glucose, since it is the main source of energy in the body. The proximal tubule reabsorbs around 98 % of all the glucose, while the distal tubule scouts out the rest. After the tubules are done with the filtration, not a single glucose molecule is left in the urine. As a matter of fact, the presence of even a few glucose molecules in the urine leads to a diagnosis of “renal glycosuria.”

After the proximal tubule, the filtrate goes into the “loop of Henle,” where it is dipped into a high-concentration environment. Water travels passively (without the need for energy) from low-concentration to high-concentration areas. In the loop of Henle, the urine is low-concentration, so water runs back into the body. Thus, any excess water in the urine is effectively and economically reabsorbed. The big machine that consists of the glomerulus, the Bowman capsule, the tubules, and the loop of Henle is called a “nephron.” Everything described above occurs in a single nephron. The average number of nephrons in one kidney is around 1,000,000. The human bladder holds around 150 ml of urine on average. So, each nephron is actually responsible for 0.00015 ml of urine production. The kidneys filter over 1,000 liters of blood each day, so our blood is kept just as we want it. Millions of tiny nephrons work in unison to take in huge amounts of blood and they know exactly what to leave and what to keep, 24 hours a day, 7 days a week.

Our blood is our life source. It is the milk of the organs, and our organs would dry up without it. Believe it or not, our organs are quite picky. If they are to receive anything they don’t like, they will start acting up. In order to keep the organs happy, the three mechanisms mentioned above have to work hard and not make a single mistake. These mechanisms are, of course, also made up of cells. These miniscule cells “know” exactly what their clients on the ends of the body like and don’t like, and prepare the blood composition accordingly. Only one word can describe these wondrous mechanisms: Impeccable.

Brian Turk is a medical student from New Jersey. He writes on medicine, health, and biology on a freelance basis.

Skin is composed of two main interwoven layers of dermis, on the inside, and epidermis, on the outside. The epidermis, which is composed of five sub units, possesses the most important sign of our identity. Each thin layer is arranged in a way to carry out different tasks. A significant amount of elasticity and flexibility is provided to skin via these five layers. These layers can glide on each other slightly and can also be compressed under pressure. They are compressed when we sit on a hard surface. This situation can be similar to the compression of the spring in a click pen, or the suspension of a vehicle under a load. They regain their previous state upon termination of the pressure, like standing up. This elasticity is crucial for skin’s integrity.

The thin construct of our skin contains sweat glands that are embedded in the fibrous connective tissue. There are sensory receptors, hair roots, and hair muscles connected to them, and also loose nerve endings, and a network of capillary vessels. Free nerve endings are created to specialize in various functions so as to sense hot, cold, pressure, and pain. Likewise, the continuation of blood flow relies on very intricate calculations that are hard to explain. When blood vessels arrive at the skin, they are dispersed like a net in the form of capillaries.

The blood pressure of the arteries located at lower section of the skin is higher than the pressure of pulmonary veins. If pressure is applied to skin for a long duration from outside, the pressure in the pulmonary veins builds up and regional blood flow is disrupted. Therefore oxygen, glucose, and other nutritional substances cannot be delivered to these areas; along with inhibition of waste product removal, it leads to a nutritional abnormality in the tissue.

Sensory cells within our skin detect and report nutritional abnormalities of tissue to our brain via various chemical substances (like acetylcholine, bradykinin, and histamine). Thus we change our position consciously or subconsciously with the intervention of our brain to avoid the danger of a nutritional abnormality, and therefore the area regains normal circulation. In this stage, the process is still reversible; however, should the pressure continue, skin cells will start to die from, from the outside in. These systems do work well in healthy persons but in cases of stroke or coma, the intervention system does not work.

This critical picture can be understood better with an example. Just like roads need to be used in order to carry goods and remove trash, the transportation of minerals, vitamins, and many other life saving substances to the distant parts of the body and removal of waste products requires blood vessels to remain open. This must continue in a perfect balance without any interruption throughout our lives.

If a pressure ulcer occurs, it is like being exposed to external dangers in a house if a door or window breaks. It is like a free entrance visa is granted to germs that were blocked. Our back and pointy areas, like, thighs knees, heels, and shoulders are under more pressure, and therefore at more risk when we lie down. Two to six hours of pressure to one of these areas is enough time to disrupt skin integrity. Our daily sleep requirement is around 6-8 hours, therefore we need to switch positions a couple of times during our sleep. Therefore we face this risk everyday in our sleep; however, thanks to the perfectly functioning protective systems, without noticing during our sleep, our position is changed and this dangerous situation is avoided. Intensive care doctors and staff know better what a great blessing that is are since intensive care patients are mostly unable to move. Despite the use of many preventive efforts, like turning the patients in certain periods or the use of air beds, pressure ulcers still occur and a significant portion of patients die of the microbial infections caused by these wounds.

The story of sleepers

“The Seven Sleepers” story in the Christian tradition is retold in the Qur’an as “the People of the Cave.” The story is about a group of young believers who took refuge in a cave fleeing the oppression of the pagan Roman emperor. Both traditions narrate that they fell asleep in the cave, where they stayed asleep for hundreds of years. The Qur’anic account, however, mentions that they were made to change position during their centuries-long sleep: “You would have thought them awake though they were asleep. We caused them to turn over to the right and the left…” (18:18). It is an interesting nuance that they were made to change position, for it sounds rather irrelevant to the rest of the story. However, with the medical conditions of our skin that were explained above, this nuance makes perfect sense as advice to us on how we should treat patients who are unable to move.

Original article: Olzsak T. et al, Science (2012, epub ahead of print)

It has been known by epidemiologists that people who grew up in farms are less likely to acquire immune diseases such as asthma, allergies, inflammatory bowel disease and multiple sclerosis when compared to people living in cities. Such observations have been the roots of “hygiene hypothesis,” which essentially points out the beneficial effects of being exposed to infectious agents. Supporting this theory, a recent study at Harvard Medical School showed that exposure to symbiotic bacteria has a long lasting beneficial effect on the immune system development. “We as a species are not exposed to the same germs that we were exposed to in the past,” said the co-author Dennis Kasper, a microbiologist at Harvard Medical School in Boston. In this study, published in Science, the researchers compared germ-free mice to mice with normal bacterial flora. Germ-free mice showed significantly higher levels of invariant natural killer T (iNKT) cells in their colons and lungs. “We made the serendipitous observation that these cells were dramatically enriched in the lung and colon in mice that lacked any microbes,” said the co-author Richard Blumberg, the chief of gastroenterology at Brigham and Woman’s Hospital in Boston. Body’s own production of elevated iNKT cells correlated with higher susceptibility to inflammatory bowel disease and allergic asthma in germ-free mice. Most strikingly, the study showed that exposure to these bacteria in late age did not lower the susceptibility to these immune diseases, indicating that the bacterial exposure needs to be early in life to boost the immune system. After all, broad-spectrum antibiotics for babies may not be such a good idea.

2- Giant chickens of Jurassic Park

Original article: Xu X. et al, Nature 484, 92 (2012)

Many of us undoubtedly learned a lot about dinosaurs from the famous Sci-fi movie Jurassic Park, but who would have imagined that some gigantic feathered dinosaurs would be running along with our favorite monster T-Rex? Paleontologists have recently made an incredible discovery in Liaoning Province of China. They found a set of perfectly preserved fossils that belong to a previously unknown species of dinosaurs. These 125-million-year-old feathered giant dinosaurs represent the largest feathered animal species ever lived on earth. The adult one is predicted to be at least 9 meters (30 feet) long with a weight of 1400 kg (~3000 pounds), which is approximately 40 times bigger than the Beipiaosaurus, largest known feathered dinosaur. New gigantic feathered dinosaurs are given a Chinese-Latin name Yutyrannus huali meaning a “beautiful feathered tyrant.” Simple filament like structures as well as the relatively small sizes of feathers seem more similar to feathers from a baby chick than the plumes of an adult bird, suggesting that Yutyrannus used feathers not for flying but for body temperature insulation, perhaps under the harsh climate conditions of that age. Paleontologists are really excited to see that how much more we have learned about dinosaurs over last 15 years and they predict that many different feathered meat-eating dinosaurs lived before and they are still yet to be discovered.

3- Stardust mystery revealed

Original article: Norris B.R.M. et al, Nature 484, 220 (2012)

Heavy elements are formed in the cores of stars and are crucial in formation of celestial structures like our earth. When an intermediate-mass star dies, it triggers a cosmic sandstorm that lasts thousands of years ejecting more than half of its mass into space. Our Sun is expected to go into a similar phase in around 5 billion years. Scientists observed these sandstorms for years but it was a mystery how these particles found could leave the vicinity of the stars and find their way into interstellar space. Computer simulations hinted that these sand-like particles could not be that small, otherwise they would be evaporated by the immense heat of the dying star. Scientists using the Very Large Telescope in Chile had a chance to explore these stars in a greater detail and discovered that the size of these particles is around a micrometer. This size might seem very small to us but for these particles, it is large enough to behave like mirrors for the light rays coming out of the star instead of absorbing them. Since light also behaves like a particle, the momentum transferred by this reflection helps particles to accelerate to the speeds like 10km/second. As the lead author of the study, Barnaby Norris from University of Sydney says: “The dust grains are like lots of little sails catching the wind, or in this case, starlight.” The material that comes out of the stars is recycled during the formation of new stellar objects like our old planet.

4- Babies understand more than we think

Original article: Bergelsona, E. & Swingley, D., P.N.A.S. 109, 3252 (2012)

Most babies do not say a meaningful word until they are a year old. It was not clear whether they knew the meaning of the words prior to the speaking age. It is easy to ask the question on whether the babies understand words but it is hard to scientifically measure it. The researchers from the University of Pennsylvania devised an ingenious experiment to test the hypothesis whether the 6-9 months babies understood the common words. During the experiment babies sat on their parents’ lap in front of a computer while some images of body parts or foods were shown on the screen. The parents were given instructions through headphones about what to say to the baby about the image on the screen. Babies were monitored by an eye-tracking device to measure their attention being directed to screen. The researchers designed a control environment by pairing a body part and a food item. For instance, if a banana and some hair were shown on the screen, the researchers measured the time that the baby fixated on the banana when the parent instructed the child to look at the banana versus when the parent instructed the baby to look at the hair. 33 infants of ages 6 to 9 months and 50 toddlers of ages 10 to 20 months were recruited for this study. The study convincingly showed that the babies fixated longer on an object when they were instructed to do so. Moreover, as the age of the babies increased the period of fixation stayed pretty much constant until 14 months, but jumped dramatically afterwards. The reason behind the jump in 14 months begs further research. Now, the researchers want also to test the vocabulary of the babies and whether the babies also understand the abstract concepts.

Original Article: Lewis, G.D. et al., Science Translational Medicine 2, 33 (2010).

Visits to biochemistry labs are frequent in our lives. Often we give blood to know levels of different metabolites, such as glucose or cholesterol. Instead of looking at a handful of metabolites, a group of scientists from Harvard Medical School has screened more than 200 metabolites before and after exercise. Interestingly, the levels of 21 of these metabolites changed significantly following exercise. The study also showed significant differences between physically more fit and less fit individuals after exercise. Following exercise, more fit people had greater increases in the biological markers of fat-burning and had decreased oxidative stress -a state where the balance between oxidants and antioxidants shift towards damaging oxidant side. Hence, fit people can get better results following exercise by efficiently removing waste materials. Moreover, exercise increased the levels of “niacinamide”, a compound which modulates insulin sensitivity. This increase was more prominent in leaner individuals and was maximized in fast marathon runners after exercise. It has been long known that obese and less-active individuals had greater tendencies to develop Type II diabetes where insulin action is impaired due to decreased sensitivity of the body to this molecule. Understanding the biochemistry behind the exercise may lead to identification of small molecules mediating its beneficial effects. These molecules may then be used to boost up metabolism or treat diseases. Until then, it is best to exercise and stay fit.

2- Our scents make us targets

Original Article: Carey, A.F. et al., Nature 464, 66 (2010).

Are you avoiding spending time outdoors in summer evenings because most of your time has to be spent chasing away the unwelcomed attention of mosquitoes? If so, then you must be one of those “lucky” people whose perspiration contains a key chemical that makes you irresistible to the six-legged bug. Scientists at Yale University have identified a key chemical compound that is detected by one of the mosquitoes’ 27 smell-receptors in their antenna. These smell-receptors are tuned to detect the key chemicals from hundreds of meters away which make people who secrete large amounts of these key chemicals in their sweat vulnerable to frequent mosquito attacks. Depending on the species, usually only the female mosquitoes bite humans, mainly on their feet or lower legs. More importantly, mosquitoes carry several deadly diseases such as Malaria and West-Nile dengue fever. In fact, Malaria is one of the deadliest and the most neglected diseases, affecting more than 500 million people and killing more than 3 million every year, mostly in sub-Saharan Africa. Sadly, the majority of deaths occur among children. Therefore, these types of studies, far from being trivial, may in fact lead to a better understanding of those mosquito-borne diseases, and hopefully may lead to the production of more effective drugs both for the prevention and the cure of diseases as well as better mosquito repellents and traps.

3- We are not alone in our body: Genomes of microbes living with us

Original Articles: Qin, J. et al., Nature 464, 59 (2010) & The Human Microbiome Jumpstart Reference Strains Consortium, Science 328, 994 (2010).

New advancements in DNA sequencing technology allow scientists to sequence genomes of microorganism living in their natural habitat. Human body contains roughly ten times as many microbes as human cells. As part of Human Microbiome Project, scientists are decoding the DNA sequences of all microbes living in several parts of our body such as skin, mouth, gut, respiratory tract and urogenital tract. Two independent teams from US and Europe have produced the first results of DNA sequences of microbes living with us. The projects have initially focused on bacterial genomes but intent to sequence viral and fungal genomes as well. The US team has generated a set of 178 bacterial reference genomes and is aiming to generate many more. In the second project funded by European Union, scientists sequenced the entire microbial DNA in the gut instead of sequencing them individually. They have sequenced more than 3 million bacterial genes, nearly 150 times more than our own (humans have only ~20 thousand genes). Importantly they have found that bacterial species are different in healthy individuals compared to the individuals with inflammatory bowel disease. Throughout these projects, scientists are trying to reveal significant information about the role of different microbial species in health and disease states.

4- Seeing with the sound

Original Article: Yovel Y et al., Science 327, 701 (2010).

Bats, dolphins, shrews and swiftlets use sound waves for navigation and hunting. They emit short sonar pulses and listen to the echoes reflecting back from solid objects. Microsecond differences in the arrival times of echoes are coded by detector neurons and used as a main cue for positioning objects in an environment. This phenomenon is known as biosonar. A recent study published in Science reveals one unknown part of this perfect sound processing strategy. The study shows that bats do not center the sonar beam on the target. Instead, they aim to match the maximum slope of the beam to the target in order to increase the signal-to- noise ratio. Around the sharp edge, small variations of the target position can be detected as a clear signal change in reflected sound intensity. Furthermore, the researchers showed that if the environment is very noisy, bats could bias this critical point to increase amplitude of the echoes. As it turns, this powerful technique has already been employed by humans in engineering and used in various technological tools such as atomic force microcopy. Whether this strategy is used in general by other echolocating animals remains to be answered.