Hypovolemic Shock

Hypovolemic shock is a serious condition in which fluid loss prevents the heart from pumping enough blood to the body. This condition can lead to death if untreated. There are other types of shock, a few of which are cardiogenic shock and neurogenic shock. Cardiogenic shock occurs when a weakened heart loses its ability to pump to the body and neurogenic shock occurs when there is a decrease in neural tone, resulting in a heart that has difficulty pumping to the body. Shock as a condition occurs, then, when tissues don’t receive enough oxygen and nutrients which leads to cell death, organ failure, and eventually whole body death (Wedro, 2007, p.3).

Hypovolemic shock is preceded by untreated hypovolemia, which results from “internal fluid shifts or external fluid losses.” Diehl-Oplinger and Kaminski (2004) state that an internal fluid shift occurs when “fluid moves out of the intravascular compartment into another area of the body, such as the interstitial space” (p. 52). Third-spacing occurs when fluid gathers in the extracellular and intracellular compartments as well as another space that doesn’t support circulation. Lastly, an external fluid loss occurs when fluid is lost externally, through occurrences such as bleeding, vomiting, surgery or trauma. Some circumstances that can result in fluid loss, and therefore shock, are vomiting, diarrhea, external bleeding, internal bleeding and burns (Diehl-Oplinger & Kaminski, 2004, p. 52).

When fluid is lost, the heart has trouble pumping blood to the body, which leads to inadequate tissue perfusion (the delivery of nutrients to tissues). The body attempts to compensate for the low blood pressure by increasing the heart rate (Russell, 1994, p. 36). The skin gets pale and clammy due to the decreased perfusion and there is a decrease in urine output, which directly correlates to the decrease of cardiac output (Russell, 1994, p.38). Rapid breathing also shows that the body is trying to maintain the acid-base balance and oxygen supply (Mower-Wade, Bartley & Chiari-Allwein, 2001, p. 23). Furthermore, the confusion and/or unconsciousness is due to the fact that the brain is very sensitive to a decrease in oxygen levels, so these symptoms show that blood is not supplying enough oxygen (Russell, 1994, p. 36). Other symptoms of shock are weakness and a lowered temperature as a result of vasoconstriction. Vasoconstriction occurs when the baroreceptors in the aortic arch respond to the fluid pressure by sending signals to the autonomic regulatory centers in the central nervous system, such as the hypothalamus, causing the vessels to constrict or dilate (Russell, 1994, p. 38).

The stages of hypovolemic shock are classified by what symptoms are present. Stage one is mild and involves anxiety and cool extremities. Stage two is moderate and involves all the symptoms of mild shock, along with increased heart and respiratory rates and decreased urine output. Stage three is severe and includes all the symptoms of moderate shock, plus hypotension and altered mental functioning, from unconsciousness to coma (Diehl- Oplinger & Kaminski, 2004, p. 52).

Diagnosing hypovolemic shock can be done through blood chemistry tests, complete blood count and x-rays (Heller, 2010, p. 2). The most important part of treatment is restoring fluid volume. IVs are given to deliver the necessary nutrients as well as replace the lost fluid (Diehl-Oplinger & Kaminski, 2004, p. 52). Medicines such as dopamine and norepinephrine can be given to increase blood pressure and cardiac output (Heller, 2010, p. 2). Placing blankets on the person to keep them warm and avoid hypothermia is very important. Also, laying the person on their back and elevating their legs improves circulation by helping the blood to return to the heart. If the person is having trouble breathing, turn him on his side.

Shock can be prevented by treating the cause and can be helped with early first aid. The severity of this emergency depends on other pathologies, the stage of shock, and age. Elderly people generally have poorer outcomes. However, immediate medical attention is necessary to save lives.

References

Diehl-Oplinger, L. & Kaminski, M. F. (2004). Choosing the right fluid to counter hypovolemic shock. Nursing 2004, 34(3), 52-54.

Heller, J. L. (2010). Hypovolemic shock. Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001220/.

Mower-Wade, D., Bartley, M. K. & Chiari-Allwein, J. L. (2001). How to respond to shock. Dimensions of Critical Care Nursing, 20(2), 22-27.

Russell, S. (1994). Hypovolemic shock. Nursing94, April, 34-39.

Wedro, B. C. (2007). Shock. Retrieved from http://www.emedicinehealth.com/shock/article_em.htm#Shock Overview.

Image: http://www.inmagine.com/paa289/paa289000015-photo

The benefit of good nutrition when living with HIV

A good nutritional status is when the body has enough of the right kind of food to functional properly for growth, repair and the maintenance of health.
People with AIDS have poor nutritional status because their body has a need for food, yet there is poor food intake on their part due to antiretroviral drugs which are usually associated with side effect that does reduce intake of food. When our bodies do not get enough food, or the right foods, we do become weak and cannot develop the right way. People with HIV have higher than normal energy needs. So a healthy diet is especially important if you are infected with HIV. Food does improve fitness and quality of life. Eating food that is balance does help to maintain the body weight, muscles and improve the performance of our immune system.
People without symptoms of HIV or opportunistic infections need 10% more calories. People with signs of other infections need 20-30% more calories. Those who have symptoms and have lost weight need 50-100% extra calories. The protein requirement is 12-15% of energy intake as for non-infected people. So the increased need is similar to that for energy. I’m not sure if HIV increases needs for nutrients. But many people with HIV have nutrient deficiencies and may even need supplements. A multi-nutrient supplement containing 100% of the daily need of all nutrients is usually helpful.

People living with HIV have weakened immune systems and so are more likely to catch infections. Infections reduce appetite but, when you are sick you need more nutrients to fight the infection, certain medications may change the tastes of foods and reduce appetite. Symptoms such as mouth sores, nausea and vomiting make it difficult to eat. Symptoms such as diarrhea reduce the absorption of food, depression, worry and tiredness reduce appetite and willingness to prepare food and eat regularly, HIV infection may lead to increased poverty and decreased access to food. People with HIV who are malnourished are sick more often and can develop AIDS and die earlier than people with HIV who are well nourished. It is very difficult to reverse malnutrition so people with HIV/AIDS need to prevent malnutrition. Rashes and itchy skin may be related to a poor diet and malnutrition. Many people with HIV are also infected with tuberculosis (TB). People with TB often lose weight. They need a healthy and balanced diet to improve their health, regain weight and replenish nutrient stores. TB patients who eat well have fewer side effects from the TB drugs and recover faster. Adjusting the diet can relieve some of the side effects of TB and TB drugs. To avoid vomiting it is advisable to eat a proper meal and it is advised that you wait half an hour before you take any drugs.
It cannot be said enough about the importance of HIV/AIDS infected individuals to eat. This is one time that overeating could be recommended. One advisement for people living with AIDS is to eat 5 to 6 small meals a day is because of HIV wasting syndrome. Hand washing is very important to protect you against infections that can be carried by Food and Water. So wash your hands before preparing food and keep all your kitchen utensils and work area clean. Wash all fruits and vegetables carefully. Do not eat raw and uncooked eggs or meat and clean up juices from raw meat quickly.
Keep leftovers refrigerated and eat them within three days. Check the expiration date on foods. Don’t buy them or eat them if they are outdated. Some germs are spread through tap water. If your Public water supply isn’t totally pure, drink boiled water.

HIV infected children can and do survive to adulthood. It is more difficult to achieve this though in many African countries whose populations have to live below the equivalent of $US 2 a day and where women and children infected with HIV are likely to be living in deep poverty. It is crucial that good nutrition is promoted most of all in these resource- poor settings.

The role of nutrition education as HIV infection develops



References
1. AIDS Community Research Initiative of America (ACRIA) (www.criany.org)
2. Centre for Disease Control National Prevention Information Network (CDCNPIN) (www.cdcnpin.org)
3. Joint United Nations Programme on HIV/AIDS (UNAIDS) (www.unaids.org)WHO. Nutrient requirements of people living with HIV/AIDS. Report of a technical consultation May 2003. www.who.int
4. Rollins, N. (October 2007), “Food Insecurity—A Risk Factor for HIV Infection”, PLoS Medicine 4(10)

Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis, sometimes call ALS or Lou Gehrig’s disease, is a disease that attacks the nerve cells (neurons) in the brain and spinal cord that is responsible for controlling voluntary muscles. Both upper and lower motor neurons degenerate/die and are unable to send messages to muscles. Over time, after not being used, the muscles weaken, waste away (atrophy), and twitch (fasciculation’s). ALS promotes the loss of the brains ability to start and control voluntary movement. Eventually muscles in the diaphragm and the chest wall fail and individuals will lose the ability to breathe without the aid of a ventilator. To be diagnosed with ALS, both upper and lower motor neurons are damaged.
ALS is one of the most common neuromuscular diseases worldwide, affecting 5 out of every 100,000 people. It most commonly strikes people between the ages of 40-60 and more men are affected than women. There is not a particular race or ethnic background diagnosed more than the other with ALS. People of all races and ethnic backgrounds are affected. Most of the time the disease will strike at random, but 5-10 percent of ALS cases is inherited. Usually, if inherited, then only one parent has to carry the gene responsible for the disease. This particular gene is still unknown, but there has been research done on superoxide dismutase 1 (SOD1). SOD1 is an enzyme and a very powerful antioxidant, protecting the body from damage caused by free radicals. If SOD1 is not doing its job likes supposed to then free radicals accumulate and cause damage to the DNA and protein in within the cells. The presence of mutant SOD1 promotes motor neuron degeneration Research is still being done and there has not been successful evidence that causes the disease.
The parts of the body that are affected depend on which muscles in the body are damaged first. Regardless of which area of the body is affected, atrophy and muscle weakness will eventually spread to other parts of the body as the disease progresses. Some of the objective problems associated with the disease are: difficulty speaking (dysarthria), difficulty swallowing (dysphagia), tight and stiff muscles, muscle cramps, muscle twitching, and atrophy of the muscles affected.
Due to not being able to find an underlying cause for the disease, unfortunately there is no cure. There are medications to relieve some of the symptoms, prevent further complications, and prolong life. The medication extends the time before the patient will need ventilation support and extends the time before a feeding tube needs to be placed. With the combination of medications and therapy, a person diagnosed with ALS is expected to live 3-5 years after the onset of symptoms. The disease usually does not affect cognitive functions so a support system is recommended. A plan will need to be made with an interdisciplinary team involving: physical therapy, respiratory therapy, occupational therapy, speech therapy, and nutritionist/dietician, social worker, in home or hospice nurses, physician, and pharmacist. This team is brought together to keep the patient as mobile and comfortable as possible.

Glaucoma in African Americans

Glaucoma is a disease that affects the optic nerve, and can eventually cause the loss of sight. Glaucoma damages the optic nerve by an increase of intraocular pressure or IOP. The optic nerve is a serious of many neurons that relay information brought in through the eyes and then integrated and organized by the visual cortex. Damage to this nerve, as a result, is often the cause for blindness. It is long been known that African Americans are at higher risk than Caucasians; new research is now explaining some of those reasons for increased susceptibility of the disease. African Americans are about six times more likely to contract Glaucoma and sixteen times more likely to experience blindness from the disease than Caucasians’ (Siegfried, 2011). Scientists are now discovering that these staggering statistics are a result of increased oxygen levels within the ocular cavity of African Americans (Siegfried, 2011). Experiments at the University of Washington set out to explain this phenomenon. Researchers placed instruments that detect PO2 levels in five significant locations within the eye; such as the anterior chamber angle which is important for intraocular fluid drainage. If fluid cannot drain properly from the eye, pressure will then build up as a result (Siegfried, 2011). Many researchers view this difference in oxygen levels as a physiological problem. Increased metabolic activity in the ocular tissue is one theory that may explain these oxygen differences (Anderson, 2011). Experiments conducted by Clara Siegfried M.D., showed that in the anterior chamber angle had a mean pressure of roughly 4.9 mm Hg difference between the Caucasian 11.7 mm Hg and the African American 16.6 mm Hg. This high pressure difference was observed in all African Americans that underwent the experiment (Anderson, 2011). "Glaucoma often affects African-Americans at a younger age," Siegfried says. "And when we used statistical methods to adjust for differences in age, the difference in oxygen levels between African-Americans and Caucasians became more significant. Then, when we controlled for racial differences, we found that increased age became an important indicator of elevated oxygen levels in certain locations in the front part of the eye (Siegfried, 2011).” This difference in oxygen concentration by age groups of African Americans are leading scientists to postulated that older African Americans may not consume oxygen in the ocular cavity at as high of rates as younger patients (Siegfried, 2011). With this said it is safe to assume that overproduction of oxygen may not be the underlying problem as other theories have proposed thus far. Dr. Siegfried still believes that there are many tests and research needed to completely unlock the physiological and genetic mechanisms that cause this race associated difference in Glaucoma patients, but will no doubt become evident in the near future. If scientists can understand why oxygen is more prevalent in African Americans, they can no doubt find a way to decrease the rate of sight loss significantly among the African American population. Though there is not yet a cure for Glaucoma, perhaps completely understanding the difference between African Americans and Caucasians with the disease can uncover new information that may one day lead to a cure.

REFERENCES

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Siegfried, C.J. (2011). More oxygen in eyes of African-americans may help explain glaucoma risk. Manuscript, Department of Integrative Physiology, University of Colorado, Boulder, Retrieved from http://www.colorado.edu/intphys/

Carla J. Siegfried, MD; Ying-Bo Shui, MD; Nancy M. Holekamp, MD; Fang Bai, MD; David C. Beebe, PhD Arch Ophthalmol. 2011;129(7):849-85doi:10.1001/archophthalmol.2011.169

Anderson, P. (2011, July 13). Oxidative metabolism in the eye differs according to race. Medscape Medical News, Retrieved from http://www.medscape.com/viewarticle/746271

Short on Time? HIIT your workout.

A common problem, or excuse, with the current obesity epidemic in relation to exercise is people don’t have the time. If people could pull themselves away from the activities soaking up their time, the newest episode of American Idol comes to mind, for just 30 minutes three times a week, people would find amazing results. There has been much debate as to the nature of endurance training versus high intensity interval training (HIIT), but the results from HIIT is ideally the best bang for the buck for most of America. An early study to show the benefits of HIIT training showed value in higher effort workouts which lead to shorter time involvement but an increase in fat loss. “At the conclusion of the study, the HIIT group lost over 3 times as much subcutaneous fat as the ET group despite expending less than half as many calories”. Though this study has been a heated topic of debate, it is hard to deny the results.

With many of the studies provided for HIIT showing benefits for people who frequently exercise, a new study showed the benefits of this style of training for the more typical sedentary, middle-aged lifestyle. Though HIIT does stand for high intensity, sedentary test subjects showed very beneficial results without working at a max load for heart rate. With 100% max efforts being used in most studies, it was not relatable to the standard person as people who do not exercise frequently would struggle with pushing their body to that limit. In a March 2011 study, an 80-95% max load was used in determining benefits for a more sedentary lifestyle. With this group having a higher risk of inactivity-related disorders, a mild time investment of an hour and a half a week proved beneficial in fat loss and muscle oxidative capacity.

Another benefit shown from this study was a 35% increase in insulin sensitivity. The conclusion of the more recent study showed “constant-load, low-volume HIT may be a practical, time-efficient strategy to induce metabolic adaptations that reduce the risk for inactivity-related disorders in previously sedentary middle-aged adults”. With our country at an unbelievable risk as two-thirds of the nation are obese or overweight, suffering from conditions due to this have continued to rise and a seemingly unaccountable nature of most, our country is in extreme danger of practically killing ourselves with excuses. People must be held accountable for allowing themselves to succumb to habits associated with being overweight and create time, as little as 30 minutes, to help themselves. Though HIIT training is not the overall answer to our obesity problems, time efficiency becomes important for many and using HIIT as a simple protocol to assist has exponential benefits no matter what body type and issues you may have.

References:
http://www.exrx.net/FatLoss/HIITvsET.html
http://www.ncbi.nlm.nih.gov/pubmed/21448086
http://sweatscience.com/high-intensity-interval-training-improves-insulin-sensitivity/
Image:
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MOOve Over Mommy!

Breast is best! That is the mantra that many mothers preach the world over. There is sound logic that backs this reasoning as well. Babies that breastfeed have a lower risk for developing obesity later on in life and generate more antibodies from routine vaccinations. Breastfed babies are also at a lower risk of developing infections and have higher levels of immunity due to the antibodies that are excreted in their mother's breastmilk. These inherited antibodies are a part of the innate immune system. They are non-specific and target numerous pathogens which enables them to protect infants from numerous infections and diseases. Thus the benefits of breastfeeding are numerous. But what happens when a mother is not able to breastfeed? The only other option is to purchase formula which while it is a good choice it is not as complete as breast milk. However, thanks to research being done in China (as strange as it may sound) mothers may soon have another option...Ol' Betsy.

According to research conducted by Bin Yang of the State Key Laboratory for Agrobiotechnology at the China Agricultural University in Beijing, genetically engineered cattle are now able to produce breastmilk more similar to that of a human. The study accomplished this by genetically altering calf embryos to increase the amount of the protein lysozyme produced during lactation. Lysozyme is naturally found in large amounts in human breastmilk while usually only in trace amounts with cows' milk. According to Yang's research this protein is significant because, "It increases the levels of beneficial intestinal microflora and strengthens disease resistance in infants. These effects are believed to occur through the lysis of certain potentially damaging Gram-positive bacteria and a few Gram-negative bacteria in the gastrointestinal tract of breast-fed babies." So lysozyme is essential for breastmilk's ability to provide immunity and prevent infection in infants.

The study followed 4 out of 17 transgenic cattle while they underwent natural lactation. The recombinant lysozyme produced by these cattle was genetically identical to that of the lysozyme found in human breastmilk. The other components of cows' milk remained virtually unchanged (i.e. total fat and protein). The scientist then went even further by purifying recombinant lysozyme. Yang's study"established a simple two-step method for the purification of the recombinant protein from milk. This purification scheme provides a new, cost-effective method for the extraction of recombinant lysozyme from transgenic milk". This discovery could pave the way for large-scale production of human lysozyme. This process could one day in the near future allow for an equivalent alternative to breastmilk when it comes to providing protection for babies from illness and disease.

The discovery of the possibility that we may be able to use bovine milk in place of human milk could have a resounding effect on infant nutrition all over the world. Mothers that find themselves unable to breastfeed, whether it be due to pathophysiology or lack of desire, may soon have an option that will provide their babies with the same type of immunological protection as their own breastmilk.



Sources:

1) Parry, w. (2011, April 04). Cows produce version of human breast milk. Live Science, Retrieved from http://www.livescience.com/13546-breast-milk-dairy-lysozyme.html

2) Yang B, Wang J, Tang B, Liu Y, Guo C, et al. 2011 Characterization of Bioactive Recombinant Human Lysozyme Expressed in Milk of Cloned Transgenic Cattle. PLoS ONE 6(3): e17593. doi:10.1371/journal.pone.0017593

Image: http://www.caddylakgraffix.com/images/favorite_sites/FAVORITE_SITES_FARM001.jpg

The Medical and Social Consequences of Alcohol Abuse

Introduction

The prevalence of alcohol related illness in the world is unknown, though there is anecdotal information that alcohol related violence, marital discord, absenteeism from work and road traffic accidents are related to the use of alcohol and are very common.

Humans have drunk alcohol for at least twelve thousand years. It has been used in religious rituals, in ancient cultures as diverse as Samaria, Babylon, Egypt, China and Anglo-Saxon Britain. According to the World Health Organisation (WHO) 1.8 million people worldwide died in 2000 from alcohol related causes, 3% of all deaths worldwide. In 2001, up to 1,000 of 3,479 deaths from suicide and self-inflicted injury were associated with the misuse of alcohol in the United Kingdom. In the United States of America, each year 85,000 deaths occur along with substantial disability from medical, psychiatric consequences, injuries and second-hand effects such as road traffic accidents attributed to the use of alcohol. The estimated annual cost attributable to alcohol use in the United States is equivalent to US$185 billion.

Repeated use of alcohol leads to habituation due to induction of liver enzymes, which increase the breakdown of alcohol. Consequently more alcohol is drunk each time in order to produce the same effect.

What is alcohol?

Alcohol or ethanol (C₂H₅OH) is a drug. It is a small water soluble molecule, a proportion of which is absorbed directly but slowly from the stomach. It is absorbed more rapidly from the small intestine and is freely distributed throughout the body. Absorption of alcohol is quicker if it is drunk on an empty stomach. Sherry with an alcohol concentration of 20% increases blood concentration more rapidly than beer (3 – 8%). Spirits such as whisky and gin (40%) delay gastric emptying and inhibit alcohol absorption. Hence people may still feel drunk the following day after much consumption of whisky or gin. Drinks aerated with carbon dioxide, for example whisky and soda and champagne, are absorbed quicker^.

Human factors in alcohol absorption

Alcohol is distributed in water throughout the body, reaching different parts such as the brain, muscles, liver and the bone marrow. Exposure of the liver to alcohol is greatest because blood received from the stomach and intestine reaches the liver through the portal vein, which drains those structures. Relatively little alcohol enters fat tissue due to its poor solubility in fat.

Compared with males, females have relatively higher fat content and hence blood and tissue concentrations of alcohol are higher in females. However other factors may also play a part in making females susceptible to the effects of alcohol.

Medical & Social effects of alcohol

Disruption of motor coordination such as driving a car or walking in a straight line due to effects of alcohol on the cerebellum, the part of the brain which modulates sensory-motor coordination. This predisposes to road traffic accidents, falls and other injuries. Removal of the voluntary control of behaviour (self control) and restraint exercised by the body through the prefrontal cortex of the brain. Hence those who have consumed much alcohol may become talkative, seek fights or urinate in public without due regard for the presence of other people. Those consuming alcohol may seek rewards such as sexual gratification without thinking of the consequences of their actions - such as unplanned pregnancy, or engaging in unprotected sexual intercourse - with the potential result of contracting serious illnesses such as HIV/AIDS. Loss of intellectual abilities such as memory, judgement, abstract thinking and reasoning.

Being uncaring and untidy about one’s personal appearance may be the first signs of alcohol abuse particularly in persons in responsible positions. Blindness due to optic atrophy if alcohol contaminated with methanol in poor brewing conditions is consumed. Cases of unexplained blindness in some middle class Southern Sudanese who have consumed locally distilled gin regularly have been noted over the years. Damage to peripheral nerves manifesting as foot drop, burning sensation in the feet and hands and leading to dropping of objects such as cups held or falls at the slightest tripping. Direct injury to heart muscle (cardiomyopathy) associated with atrial fibrillation (irregular heartbeat) leading to heart failure and strokes. Chronic pancreatitis and ultimately diabetes.

Gynaecomastia (enlarged breasts in men), atrophy of testicles and erectile impotence. This is believed to be due to the effect of oestrogens whose concentration increases in the body as a result of poor inactivation in the liver which has already been rendered cirrhotic by excessive consumption of alcohol. Fetal alcohol syndrome: excessive alcohol consumption during pregnancy leads to fetal retardation, central nervous system abnormalities in the fetus such as small openings between the eyelids, thin upper lid, upturned nose, parallel folds on ears and mental retardation leading to impaired learning, slow reaction time and poor problem solving. Dehydration: alcohol inhibits the release of vasopressin from the posterior pituitary gland leading to increase in urine volume and consequently dehydration. This may lead to kidney failure if not corrected. Marital disharmony as a result of cash crisis, domestic violence, loss of job and social exclusion. Violence leading to homicides, assaults and sometimes burglary. Failure at examinations for those who are at school, college or university. Loss of trust by those close to the person abusing alcohol (no-one trusts a drunkard!).

These and more are some of the major consequences of chronic and excessive alcohol consumption. Drunk in small quantities alcohol may be beneficial.

There are ways round problems in life other than is encapsulated in this quote, “Alcohol is the anesthesia by which we endure the operation of life” George Barnard Shaw 1856 – 1950.

References

1. Alcohol and Human Health. Eds. Lesley Smart, Oxford University Press 2007.
2. World Health Organisation 2002.
3. ABC of Alcohol. Ed Alex Paton and Robin Touquet, Blackwell Publishing 4^th Edition 2005.
4. Richard Saitz, Unhealthy Alcohol use. NEJM 2005; 352:596 – 607.
5. BMJ 2005; 330: 85 – 87.
6. National Institute of Alcohol Abuse and lcoholism2000.http://pubs.niaaa.nih.govpublications/aa50.htm.

Orexin Neurons and the Fight or Flight Response

The “fight or flight” response is an involuntary chemical and physical reaction controlled by the autonomic nervous system. More specifically, the Hypothalamus has been proven to play a key role in the triggering of the response, but the exact “mechanisms” have been elusive (Tomoyukast, 2011). New research from the Kagoshima University in Japan has located the origins of the so called “defense response” and how,” the hypothalamus seems to act as a master switch for the fight or flight response” (Tomoyukast, 2011). The answer is orexin (hypocretin) neurons.

The orexin neuron or hypocretin neuron is also referred to as a hypothalamic neuro- peptide. These neurons are found in the dorsomedial hypothalamus, which has been known to be the area that controls the reward process, pain process, and regulates the autonomic response of the cardiovascular, respiratory, and nuroendocrine system (Natsuk, Akihiro, Kanako, Yo, & Kilduff, 2005). These Orexin neurons are however, found all throughout the cerebral cortex, brainstem, and other areas of the body. This has shown scientists that these neurons have widespread connections throughout specific parts of the body but most importantly the cardio-respiratory areas that are controlled by the fight or flight response (Tomoyukast, 2011). A study preformed on mice was devised to show the relationship to the fight or flight response and the orexin neurons. Mice were exposed to extreme cold to induce hyperthermia. The cold acts as a stressor which turns on the fight or flight response mechanisms. The orexin neurons then send signals to one another that in turn regulate the cardio vascular and reparatory stress responses, and at the same time also work to control body temperature to prepare the body for “fight or flight behavior” (Tomoyukast, 2011).

Orexin neurons are intricately connected within a very precise network of autonomic reflex pathways and conscious and unconscious receptors and regulators. These neurons connect the biological clock as well as the sleep/ wakefulness autonomic responses to the dorsal hypothalamus; which can then in turn send appropriate signals down the orexin neurons to trigger the fight of flight mechanisms (Natsuk, Akihiro, Kanako, Yo, & Kilduff, 2005). This network sends all the appropriate information simultaneously through the body by way of the orexin neurons. This seemingly instantaneous system is the mechanism in which the fight or flight response is accomplished. Orexin neurons are a very specific type of neuron with a very specific function; unfortunately the neurotransmitters used by these neurons are still unknown but some have been proposed such as; 5HT-1A and 5HT-3 (Tomoyukast, 2011). These two neurotransmitters are proposed to be used during the defense response within the cardiovascular reflex pathways (Natsuk, Akihiro, Kanako, Yo, & Kilduff, 2005).

From the dorsal hyper thalamus to the cerebral cortex and brainstem to the cardiovascular, respiratory, and endocrine systems (the list continues) one can find an orexin neuron. Without the specificity of this neuron the basic stress response of the fight of flight mechanism may not have been possible, and this would have had an unexplainable effect on a species survivability in the wild.

REFERENCES

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Tomoyukast, K. (2011). A key role of orexin (hypocretin) neurons in the fight-or-flight response. Physiology News Magazine, 1(83), Retrieved from http://www.physoc.org/uploadedfiles/documentlibrary/824.pdf

Natsuk, T., Akihiro, Y., Kanako, I., Yo, M., & Kilduff, T.S. (2005). Cholecystokinin activates orexin/hypocretin neurons through the cholecystokinin a receptor. The Journal of Neuroscience, 25(32), 7459-7469.

Drink water and lose weight!

Recent research is saying that an effective, inexpensive way to lose weight is to drink water upon the first signs of hunger and wait 15 minutes to see if you are then satisfied. This is effective because many people confuse thirst signals as hunger signals, prompting them to overeat. This confusion is due to an inability to read the body’s signals as well as the fact that, according to Nutritional Therapist Pat Reeves, “the sensations of thirst and hunger are often generated simultaneously. …we assume both indicators mean that food is needed by the body: So we eat food when the body should, ideally, only be receiving water” (p . 1). Hunger and thirst are both controlled by the hypothalamus, which can trigger them at the same time, resulting in confusion.

Thirst, which is a perception that provides the urge for fluid consumption, is regulated by neural signals under both hormonal and osmotic influence. Vomiting, diarrhea, excess salt and sugar consumption, perspiration, and simply being alive cause fluid loss. Breathing, sweating and urinating are all daily activities that cause a depletion of body fluid.

When there is a decrease in fluid volume, the urge to drink is formed in order to maintain homeostasis by increasing fluid consumption. According to Johnson and McKinley (2004), “specific sensors in the brain, termed osmoreceptors, respond to cellular dehydration to initiate neural mechanisms that result in the generation of thirst” (p. 1) Other responses such as sympathetic activation and reduced water excretion attempt to minimize any further changes in fluid volume by reabsorbing and retaining water and sodium. However, body fluids will not be restored until the fluid losses are replenished. Thirst is the perception that will cause this to occur.

Several hormones, such as peptides and steroids, also play a part in thirst regulation. For example, relaxin, which is a peptide, stimulates fluid consumption by stimulating vasopressin secretion. Vasopressin is a hormone that is secreted when there is a reduced volume of extracellular fluid. It is an anti-diuretic hormone that causes re-absorption of water and reduced fluid excretion.

When feeling thirsty, the optimal solution is to drink water, not other liquids. Reeves stated that, “The reason why people often become addicted to coffee and diet fizzy drinks is because the water does not stay in the body long enough to satisfy thirst and also has a direct action on the brain, giving a sensation of pleasure” (p. 2). Other liquids such as juice or soda do not fully satisfy thirst, causing people to then go to food for satisfaction when water is what is needed.

Also, hunger signals are sent when blood sugar is low, but water can be a source of energy similar to food. Energy is released when water molecules are split into hydrogen and oxygen during hydrolysis, which releases energy and ATP, the most essential compound in cellular metabolism.

In conclusion, knowing how to interpret your body’s signals and drinking water consistently throughout the day can aid weight loss by maintaining hydration and preventing over-eating. It is widely known that water is essential in every aspect of the body and that dehydration is very dangerous. However, over-eating is dangerous as well, since it can lead to excess weight gain and all the problems associated with being overweight. Ensuring proper fluid volume through constant water intake is the only way to prevent these issues.

References:

Reeves, P. Overweight- the water connection. Retrieved from http://www.foodalive.org/articles/overweight.htm.

Johnson, A. K. & McKinley, M. J. (2004). The physiological regulation of thirst and fluid intake. News in Physioloical Sciences, 19. Retrieved from http://physiologyonline.physiology.org/content/19/1/1.full.pdf+html.

Image:

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Coffee and the Fight Against Type 2 Diabetes

Great news for all you coffee lovers out there! According to a recent study conducted at the University of California in Los Angeles, habitual caffeinated coffee consumption of at least 4 cups a day may decrease your risk for developing type 2 diabetes. This news could not have come at a better time as diabetes, especially type 2 diabetes, is sharply on the rise. The American Diabetes Association estimates that, “nearly 24 million children and adults in the U.S. -- nearly 8 percent of the population -- have diabetes. Type 2 diabetes is the most common form of the disease and accounts for about 90 to 95 percent of these cases”. Many of the risk factors for developing type 2 diabetes are modifiable, especially diet. Can it really be as simple as adding some “java” to your morning routine? Researchers at UCLA say it’s a possibility.

It has long been thought that there is an inverse association between drinking coffee and type 2 diabetes risk but the actual reason as to why this is true has baffled scientists for years. Researchers at UCLA believe they may have finally discovered the mechanism behind this relationship. It is a protein called sex hormone-binding globulin (SHBG). Its job is to regulate the body’s sex hormones which have been associtaed with the development of type 2 diabetes. It appears that the higher the plasma level of SHBG the lower the risk for an individual to develop type 2 diabetes. Coffee it turns out raises the plasma level of SHBG in the blood. The more coffee consumed the higher the plasma level of SHBG. SHBG is also metabolized in the liver and caffeinated coffee alters the activity of liver enzymes. This suggests that SHBG metabolism may be affected by components found in coffee which leads to the increase in plasma SHBG.

The researchers at UCLA drew their test subjects from a Women’s Health Study that was “originally designed to evaluate the benefits and risks of low-dose aspirin and vitamin E in the primary prevention of cardiovascular disease and cancer”. The study spanned 10 years and followed roughly 40,000 women. Out of those subjects 359 postmenopausal women with newly diagnosed type 2 diabetes were matched to 359 control subjects. With the results of this study researchers were able to make a positive association between caffeinated coffee intake and plasma SHBG levels. In fact their results showed that habitual coffee drinkers “were 56 percent less likely to develop diabetes than were non drinkers”.

A previous genetic study conducted by Dr. Simin Liu further supports the proposed association. They found two mutations in the gene coding of SHBG that demonstrate an effect on the risk of developing type 2 diabetes. Carriers of the rs6259 minor allele had a ten percent higher concentration of plasma SHBG which decreased their risk. However, carriers of an rs6257 minor allele had a ten percent lower concentration that put them at greater risk for developing the disease. Liu’s work shows that there is a genetic component as to the propensity for an individual to develop diabetes based on the amount of SHBG in their blood.

Coffee has long been recognized for having a protective effect against type 2 diabetes but the reasoning behind it has been unclear. A high concentration of plasma SHBG has also been shown to have this effect. Upon further investigation it is now proposed that coffee increases plasma levels of SHBG and that this may be the mechanism behind its decreased risk for developing type 2 diabetes. So next time you're debating whether or not to have that extra cup (or four), go for it!



Sources

1. Ding EL, Song Y, Manson JE, et al. Sex hormone-binding globulin and risk of type 2 diabetes in women and men. N Engl J Med 2009;361:1152-1163

2. Jayagopal V, Kilpatrick ES,Jennings PE, Holding S, Hepburn DA, Atikin SL. The biological variation of sex hormone-binding globulin in type 2 diabetes:implications for sex hormone-binding globulin as a surrogate marker of insulin resistance. Diabetes Care. 2004;27:278

3. Wheeler, Mark. University of California - Los Angeles. "Why coffee protects against diabetes." ScienceDaily, 15 Jan. 2011. Web. 17 Jun. 2011 from http://www.sciencedaily.com­ /releases/2011/01/110113102200.htm

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Meal Frequency and You!

How many of us have been told to eat frequently to keep our metabolism burning? That you need to eat more times a day with smaller meals to keep your body at peak performance while losing more fat.

Yes, I’ve heard it plenty and I finally went outside the box and found there is more to controlling your diet than just size and frequency. I came across a style of eating called intermittent fasting which is built around a 16 hour fasting period followed by an eight hour eating period in which you eat the normal maintenance calories you would in a typical day. While commonplace in gyms and magazines, the evidence against meal frequency was limited but a study, Bellisle F et. al. Meal frequency and energy balance. Br J Nutr. (1997), went through all pertinent studies related to meal frequency and weight loss and determined there was little correlation in the studies showing more or less fat loss in any groups, with most studies coming up neutral.

A more recent study done in 2009 at the University of Ottawa placed 16 obese individuals, split by eight men and eight women, all on a diet restriction the same between each. One group would eat 3 meals and 3 snacks in a day while the other would only eat 3 meals a day. The study last 8 weeks and in all groups the findings of lean body mass, body fat and BMI were all within similar ranges showing no metabolic differences with meal frequency.

The author reviewing the 1997 study points out some common misconceptions leading to the higher meal frequency belief. A primary one being the misunderstanding of the thermal effect of food, which people took as the more you eat, the more calories you burn. In theory, this is a practical explanation. What generally is not accounted for is that eating in this style requires you to eat more food. Though technically you will be burning more calories, it would still be at a same rate of 10% of intake of calories. So, if you take in an additional amount of calories, of course you will burn more, but you will have consumed a higher total number of calories to only have a small percentage burned off.

For people looking to follow a high frequency meal plan, it can be a tedious process to prepare so many meals just for one day and to keep up with it day after day. The studies show there is little value to when you eat and the amount your body can burn off metabolically. There are many alternate styles of eating out there and our bodies react differently. I have tried various diets to see how my body changes with them and thus far for my own case, a version of intermittent fasting has been working extremely well. Had I not opened my mind and tried something everything I had learned up to that point said not to do, I wouldn’t have found an effective plan that works very well for me and my lifestyle. Don’t let myths stop you from trying new things which could keep something you’re looking for out of reach.

Sources:
http://www.bodyrecomposition.com/research-review/meal-frequency-and-energy-balance-research-review.html#more-1389
http://www.ncbi.nlm.nih.gov/pubmed/19943985
http://www.nytimes.com/2010/03/23/health/23really.html?src=sch&pagewanted=all
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