Genetic Engineering in Medicine

Introduction

Genetic Engineering has given scientists more power than they have ever had. Through genetic engineering, scientists have the power to rewrite an organism's genetic instructions, thus giving it properties which nature never intended it to have. ''The major economic impact of genetic engineering will be even greater in the chemical and energy industries than in the health-care field,'' said Edward Lanphier of International Resource Development Inc.

However, one of the fields which genetic engineering promises to change the most is the field of medicine. From vaccines in Bananas to genetically engineered transplant organs, genetic engineering promises to alter the way that we see medicine.

Vaccines

Banana Vaccines

Research being done on potatoes show that genes can be put successfully into potato plants that will make vaccines against cholera, diarrhea and hepatitis B. Scientists hope to be able to genetically engineer bananas to have vaccines in them. The bananas would then be grown in developing countries, where disease such as cholera and diarrhea are very prevalent. This would be a much cheaper alternative to the wasteful process of a series of shots, throwing away costly syringes after every injection. About 300 million people are carriers of hepatitis B, which can cause liver failure and liver cancer. Diarrhea is a common cause of death in young children.

"The next step is to achieve higher doses of vaccines in plants, ensure that the human immune system
recognizes the vaccine and develop vaccine-producing banana trees, which take three years to grow. If all goes well, Yasmin Thanavala (of the Roswell Park Cancer Institute, Buffalo, New York). says banana vaccines may be ready to peel in five years."

DNA Vaccines

In the past 100 years, the most effective and most common type of vaccination involved the injection of proteins. The reason that protein injections are used is now evident: for the body to become immune, the immune system needs certain properties (peptide epitopes) found in proteins, in order to be effectively immunized. A new development in immunization is DNA-mediated immunization, known as DNA vaccines.
A DNA vaccine involves the direct injection of plasmid DNA encoding an antigenic protein which is then expressed within cells of the organism, making the organism effectively immune to the disease. The vaccines are injected with needles or through the skin. Although only a small amount of cells are effected, the reaction which is not fully understood somehow effectively immunizes the body.

Antibiotics

Genetic Engineering will have a great effect on the manfucturing of antibiotics. So far, antibiotics worth $4 billion to $5 billion have been produced. The International Resource Development Corporation has projected a $3 billion annual market by 1990 specifically for drugs produced by genetically eningeered organisms.

The way that this would work is that we would get a certain desirable chemical from an organism, and then insert the gene that codes for that one chemical into a bacteria such as E. Coli. Bacteria reproduce very quickly, so in about 24 hours, scientist would have enough of the chemical to harvest and sell as a drug.

Xenotransplantation

Xenotransplantation is the process of taking an organ from a certain species and transplanting that organ into another species. Until recently, Alltotransplantion, the process of transplanting organs in the same species has been the only method of transplantation. For the last 25 years, heart valves from pigs have been used in human patients. There are between 32,000 and 40,000 people in the United States that need an organ transplant. The number of human donor organs in no way meets this demand. Many of the people waiting for transplants will die without them. The only solution from a scientific standpoint is to genetically alter organs in a species similar to humans and use those organs for transplanting. Pigs are the animal that scientists are focusing on as they are over 99% similar in there DNA makeup. They still are not close enough because if an organ from a pig is but into a human, the would human reject the organ. This means that something has to be done to the pig organ to make it even more similar in its DNA makeup so that the human body will not reject the organ. If this procedure is perfected and scientists do make a pig with nearly identical DNA to a human, it would have the potential to save hundreds of thousands of lives per year.

Why Pigs?

Pigs were chosen over primates such as the chimpanzee which have even more similar DNA to humans for several reasons. First, Pigs breed rapidly and are easy and cost effective to raise. Second, they are free of all known diseases. The reason they were chosen over primates is that many primates are dwindling in number and are very hard to breed. Using organs from chimps would not only kill the animal but reduce the number of chimps significantly enough to raise concerns about extinction. Genetic engineering in pigs would allow pig cells to produce human proteins that prevent the organ from being rejected. In the United States there are about 18,000 organ transplants a year. There is also an additional 32,000 to 40,000 qualified patients waiting for organ transplants and another 100,000 people die without qualifying. If Xenotransplantation was perfected it would initially be used to prolong a patients life until a human donor organ is available. Pharmaceutical companies will be investing billions of dollars over the next few years in Xenotransplantation and in theory, 100,000 lives could be saved per year worldwide.

So why not do it?

First there are ethical questions. Is it right to kill a pig to save or prolong the life of a human? Is it okay to alter the genetic makeup of animals? Is it okay to transplant organs in general? What would different religions think about this? Would a human that is in need of an organ transplant resist having an organ from another species put into them? To answer this question, you have to answer this question. Is there a difference between transplanting an organ from a pig and putting it into your body and eating Pork? A recent survey conducted in the United States. concludes that 51% of the people surveyed would not object to having an organ from another species if needed. The other reasons for not doing Xenotransplantations are scientific. What are the dangers if any? It is not known if there would be any dangers in Xenotransplantation, but it would be possible for a virus that has never affected the human race to be passed on f However, transplant scientists feel that they could overcome that obstacle fairly easily. How long would a human live with a organ from a pig? A pigs life span is around 30 years. If the human got the organ transplanted early in life, would the organ last only 30 years? No body knows that answer. Is it actually possible? Austrian scientists think so. In October of 1995, they announced that they had made progress in genetically engineering animal to grow organs that will not be rejected. Those scientists expect to run clinical trials by the late 1990's. There first proposed test would be to transplant a pig organ into a primate and then move on to humans. Another experiment in this field is to produce insulin-producing cells from specifically bred pigs. This has enabled monkey transplant recipients to overcome diabetes. Human tests are planned soon for this procedure. This process could have the potential to cure all diabetes patients. There have also been some success in transplanting Pig organs into baboons. Scientists first genetically altered the DNA makeup of several litters of pigs so that they would have some of the same markings that are found in humans. They then transplanted a "transgenic" pig's heart into a baboon. Usually after about 90 minutes of working properly, the heart fails and the organism dies. Instead, all three of the baboons experimented on survived for several hours, and one lived longer than a day. Those results would be nothing to brag about as living a day longer isn't very successful, but it is a step in the direction of success.

The Future

In the past three years there has been a great deal of interest in Xenotransplantation. The reasons for this interest are clear. If the process was successfully mastered, it would have the potential to save 100,000 lives a year. This would definitely effect all of us. For this reason it is important for scientists to wait and find out what the informed population thinks about Xenotransplantation. I have no doubt after researching Xenotransplantation that in the next few years, scientists will have perfected the procedure and be ready to use genetically altered Pig organs to save human lives. However, before they jump into this they must educate the people about developments and find out what they think. The Ethical issues will have to be addressed. New laws will have to be created. We should all educate ourselves about these issues so that we can make wise decisions that will effect all of us.

Nat
(http://plweb.csmonitor.com/plweb-turbo/cgi-bin/fastweb?getdoc+plain1+archives+29221+85++Genetic%20Engineering%20in%20Medicine) (http://www.usatoday.com/life/health/lhs430.htm)
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Genetic Engineering in Medicine

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