Tutor profile: Jennifer H.
What is a trans fat, and why is it used commercially? Also explain why is it deleterious to human health?
Trans fat is produced naturally, in small amounts during ruminant digestion. However, the majority of this type of fat is manufactured in foods such as chips, baked goods, packaged foods and stick margarine. They are generated by partially hydrogenating unsaturated fats by "pumping" hydrogen molecules into it and changing the configuration of the double bonds from a cis (same side) to a trans (opposite side) configuration, resulting in a straighter molecule that can pack together more molecules of fat, resulting in a fat that is solid at room temperature. It is this feature of being solid at room temperature that made it optimal for texture qualities in some food products, a feature that cannot be attained through the utilization of saturated fats. However, research concludes that there is no nutritional or medical benefit to it's consumption and has in fact been outlawed in some countries due to it's role in cardiovascular disease. Trans fat increases the level of LDL cholesterol, which is a contributing factor to the development of coronary artery disease, by depositing cholesterol on the intima of blood vessels. It also lowers the good (HDL) cholesterol that functions in ridding the blood vessels of fatty acids. It also perturbs he metabolism of essential fatty acids, resulting in changes in phospholipid composition in cells and reducing the compliancy of blood vessels . Trans fats also contributes further to central/visceral adiposity and insulin resistance.
Subject: Biomedical Science
Explain, briefly, what diabetes (DM)and cardiovascular disease (CVD), explain the relationship between he two chronic diseases, and touch on the pathogenic mechanisms that precipitate CVD.
Diabetes mellitis (DM) is a disease characterized by insufficient insulin production and subsequent hyperglycemia (high blood sugar). There are two types: in type 1, it's caused by an autoimmune mediated destruction of insulin producing beta pancreatic cells and in type 2, it's caused by insulin sensitivity. Where an individuals blood sugar levels are perpetually elevated, insulin is constantly released into circulation to cause somatic cells to uptake the glucose (sugar) and curtail the hyperglycemia to the point where the cells become resistant to the profuse quantity of insulin, and euglycemia or normal blood glucose levels can't be attained. In the latter case, this generally occurs because of sedentary lifestyle and poor food habits, and a diet rich in added sugars and simple carbohydrates. In some cases, the uncontrolled diabetic metabolic state can actually cause destruction of the pancreatic beta cells, i.e. the high glucose levels and lipids produced by this metabolic derangement. Cardiovascular disease (CVD) is a broad envelope including: peripheral artery disease (atherosclerosis), heart related blockages (coronary artery disease), cardiomyopathy, angina, myocardial infarction, hypertension etc. These and other related diseases stem from: smoking, poor diet, sedentary lifestyle, high blood cholesterol, and of course diabetes. Uncontrolled hyperglycemia causes dyslipidemia due to the fact that insulin stimulates lipoprotein lipase that promotes free fatty acid uptake by adipose (fat) issues. The resulting trigyceridemia increases "bad" cholesterol or small dense LDL cholesterol (promotes fat deposition in blood vessels) while also reducing the concentration of "good" cholesterol or HDL that are responsible for mopping up cholesterol in the blood vessels. High blood cholesterol promotes fatty acid oxidation, immune system involvement, inflammatory mediator release and immune cells like leukocytes and macrophages to subsequently be recruited to the area to ameliorate the fatty mass accumulation. It also stimulates smooth muscle cell and endothelial cells to proliferate in an attempt to repair the area.This in turn causes the immune cells to become overwhelmed by lipids which morph into fat laden foam cells, which reinforces the dysfunctional immune response and incorporating more lipids into the developing plaque as well as calcium salts that calcify and destabilize the plaque. In addition, the extensibility and fluidity of the vessels become compromised, causing a problematic situation where the vessels can't expand regularly to accommodate blood flow, and the vessel diameter is lessened. Hyperglycemia also causes glycation, of red blood cells, the inner layer (endothelium) of blood vessels, receptors (etc.) where sugar molecules attach themselves to proteins.This cases neuropathy, nephropathy, and leads to CVD related issues such as endothelial dysfunction and inflammation,. To conclude, the consequence of hyperglycemia and insulin sensitivity and poor dietary practices which overemphasize bad fats and simple carbohydrates can generate a series of cascading events that cause inflammation, metabolic derangement including dyslipidemia, endothelial dysfunction, vascular complications and a host of other pathogenic and molecular causative factors that lead to CVD.
A yearly flu vaccination aids in the ability for individuals to come out of the influenza season unscathed. But how does work, and why is it highly recommended that all members of the population receive one, and are there sectors of the population that should stringently seek it over others?
The Influenza virus is a highly contagious pathogen that resides in high numbers within the saliva and mucus secretions of persons infected with the virus, and can be easily dispersed to other individuals in proximity even among those who are asymptomatic (while the virus is incubating and replicating). It can also survive on contaminated objects for a few days, hence, acting as an environmental vector for disease dissemination. The specifics of symptomolgy and pathogenesis is beyond the scope of this brief introduction. Suffice it to say, it's virulence or infecting power is determined by Neurominidase and Hemagglutinin which are proteins on the surface of the flu virus. They interact with the respiratory epithelia, invading the cell and usurping control over the host cell DNA machinery to produce viral proteins, and hence, more viral particles that spread in the infected host and subsequently to others. There are various types of these proteins which can invade and infect the respiratory epithelia of one who is not immunologically primed to that specific viral combination or antigen and can cause upper respiratory symptoms indicative of the flu. It can also cause pneumonia and secondary respiratory infections depending on the virulence of the virus, the health status and the functioning capacity of one's immune system. Flu vaccines work by delivering the viral antigen to the immune system, which subsequently produces antibodies to that specific strain. The vaccine is conventionally produced by infecting a fertilized chicken embryo with the virus, the virus is then extrapolated, inactivated and the DNA purified so as to be left with the viral antigen within a suspension medium which is void of the infective virulent portion that could cause the flu. Here are a couple of different ways to purify the flu antigen that however will not be discussed further here. The vaccines are not perfect, as it is a researchers best educated guess as to which strain will predominate. There's a lot of controversy on whether or not to vaccinate, and many people believe it may actually cause the flu. That is of course not true, muscle pain (it's a intramuscular injection) and fatigue might be a consequence, and it certainly doesn't cause or precipitate disease. In fact, failing to vaccinate yourself and your children, exposes others who can't be vaccinated for various reasons including those who have severe anaphylaxis and babies under 6 months, at heightened risk of severe infection and potential death. People particularly vulnerable to infection and complicated cases include: those with chronic medical conditions, the elderly, infants and immuno-compromised individuals. It provides "herd immunity", which is an epidemiological phenomenon defined as a lowered infection rate and spread due to a high proportion of the population being vaccinated to a given disease. It is recommended that all individuals over 6 months of age be vaccinated.
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