NOTE: Free essay sample provided on this page should be used for references or sample purposes only. The sample essay is available to anyone, so any direct quoting without mentioning the source will be considered plagiarism by schools, colleges and universities that use plagiarism detection software. To get a completely brand-new, plagiarism-free essay, please use our essay writing service.
One click instant price quote
... were 3 months old, their brains had degenerated and contained spongy tissue. Although the brain matter had been damaged, the neurons had yet to be affected and the mice presented no symptoms. Days after the enzyme production, the PrP gene stopped producing PrP and the remaining quantities of PrP were quickly broken down by protease. With no new protein for the infectious form to convert, the disease progression stopped and slowly reversed. The holes within the brain healed and the mice returned to normal.
A year after the experiment, the mice have fully healed and are now living a normal life, (Collinge, 2003). This is only in the first stages of research and not possible from human trials. Although the knowledge of the existence of prions has been only around for a short while in the face of human history, it is thought by many that prions have been infecting mammals for hundreds of thousands of years. John Collinge and his team examined the DNA of members of the Fore tribe and that of 1000 others representing the ethnic groups around the world. It was found that everyone had a combination of two variants of the PrP gene.
Based on the widespread existence of the variants, Collinge theorized that the variants diverged from the original around 500 000 years ago. Collinge (2003) thought that due to the prevalence of the two variants, they must have undergone strong natural selection pressure. Among the Fore tribe, there was an unusually high amount of women, over the age of 50, who had a copy of each gene variant. The high amount suggested that having a copy of each variant protected against Kuru.
This is similar to the variants of the hemoglobin gene, one of which causes sickle cell anemia (when inherited in homozygous pairs), while also protecting against malaria (when paired with non-sickle cell variant). Therefore the distribution of the gene variants throughout the human population suggests that illnesses caused by prions were common in early human history. In our world today, there are many diseases that affect the lives of millions of people everyday. Many of these illnesses can be treated or even cured, but there are still those that cannot. Unfortunately, any disease that is caused by a prion can neither be cured nor be treated. This may change in years to come but right now we must find a way to deal with the implications of these diseases on daily life.
One of the most significant ways by which prions can affect us is also the least common. The few people each year who are infected by one of the various human prion diseases will eventually die, this not only affects the afflicted, but also the people around them. The other way by which prions can affect people is through animals. There are countless ways that a sick animal can affect people, but the most significant is through the meat industry. When any livestock animal becomes ill, there is a fear that the rest of the animals will also become infected. As with all prion caused diseases, there are no ways to determine for certain that an animal is infected without dissecting the brain.
Due to this fact, the easiest preventative measure is to simply burn the entire herd (Prusiner, 1995). When many herds are disposed of, there is a draining effect on smaller communities. This does not only affect people, but it also impacts on trade. Other regions are less likely to import meat that might be contaminated.
This has happened many times all over the world. Countries do not want to buy meat from a country that has had a case of mad cow disease or BSE. There are many precautions taken by medical facilities to ensure the safety of the staff and other patients when a person with a prion disease is being treated. Lois Nolan (1998) states that, When a CJD case comes in, it definitely sets the place on edge. Hearts stop, everybody is very alert, and then pay real strict attention to policy. Rarely do two medical facilities have the same policy to deal with a prion related disease, though most use a variant of the procedure recommended by the CDC (Center for Disease Control and Prevention).
That procedure is to use as few instruments and supplies and as many disposables as possible. All items that require ethylene oxide sterilization should be excluded. The use of power tools is restricted, and all unneeded items must be removed from the operating room. Access should be limited to only essential people, and FULL protective apparel should be worn, including eyewear, hats, masks, shoe covers, gowns and double gloves. All of the non-disposable instruments that were used must be disinfected by immersion in a solution of 5 % sodium hypochlorite for 2 hours.
Then they must be steam-sterilized at a temperature of 132 degrees Celsius or above for another hour. The CDC feels that extreme precaution should be applied due to the high degree of hazard and the inevitable death of those who are infected. Contrary to common belief, prions do not always bring about neurodegenerative diseases; sometimes they serve a useful purpose. Recently at the Columbia University College of Physicians and Surgeons in New York City, neuroscientist Eric Kandel and former doctor Kausik Si lead a team to investigate the memory neurons of the Aplysia sea slug. It was found that the stimulation of a memory neuron causes the protein called CPEB to stimulate mRNA to begin translation and create a protein.
There was a question that still needed to be answered. Since most proteins break down within a few hours, how could CPEB maintain the stimulation of mRNA over extended periods of time? It was then noticed that on some of the CPEB proteins there was a small prion-like portion located at the end. According to Kandel and Si (2004), the CPEB protein, like prions, had two forms, one which soluble and the other which was not.
The insoluble proteins convert the soluble proteins and thus help form long-term memory in mammals. Although this theory is far from being confirmed, it helped start the search for other helpful actions of prions and prion-like proteins. References Prusiner, S. B. (1995).
The prion diseases. Scientific American, Vol. 272, Issue 1, p. 48 Shimkus, J. (1998). Alien Invasion. AHA News, Vol. 34, Issue 7, p. 5 Penis, E. (2003). Cannibalism and Prion Disease May Have Been Rampant in Ancient Humans. Science, Vol. 300, Issue 5617 Cousin, J. (2003).
In a First, Infected Mice Recover From Prion Disease. Science, Vol. 302, Issue 5646, p. 763 Wickelgren, I. (2004). A Good Side of Prions? Science Now
Free research essays on topics related to: prion, prion diseases, human history, science vol, sickle cell
Research essay sample on Prion Diseases Sickle Cell
