Sunday, 3 May 2015

GENETIC ENGINEERING

DNA is a molecule located in the nucleus of every eukaryotic cell and the in the cytoplasm of prokaryotic cells and it is basically the recipe for life. Genetic Engineering is a branch of the genetics which is based on the study of the DNA to that end of its manipulation; the process of manually adding new DNA to an organism on purpose of adding one or more new traits that are not found in the organism we are working on.
Here we are going to see some examples:

1.  INTERFERON:
It is a protein made by the immune system in the presence of infections and pathogens, to enhance the response of the defense cells and thus more effectively fight the aggressor agent forms.
The British virologist Alick Isaacs and his Swiss colleague Jean Lindenmann were first identified in 1957, one of these proteins in chicken embryo cells. Interferon can be classified into three groups: the α interferon (leukocyte), produced by white blood cells; The interferon β (fibroblast) produced by skin cells; and interferon gamma (immune), produced by lymphocytes when stimulated by antigens.
During the 1960s, doctors tried to treat some viral diseases, especially the common cold, by administration of interferon, but this was not practical due to the very high cost of extracting the substance of human white blood cells (always in small amounts). The next step was to try to stimulate the body to produce interferon: synthetic inducers such as nucleic acids were used. These fulfilled its function, but soon developed tolerance, and ceased to exert its effect. In 1980, interferon became available in larger quantities through the development of genetic engineering techniques, and the following year began clinical trials and performed to establish the levels, doses and side effects.
They are revealed as a promising treatment against many viral infections. They are also valuable in the treatment of multiple sclerosis forms, but the results have been variable against various cancers, leukemias and some lymphomas. To some extent they could be effective against malignant melanoma, renal cell cancer, hepatitis C and a minority of Kaposi sarcoma associated with AIDS. Side effects can be mild or severe. The β interferons and g have not been sufficiently tested, but could prove more effective than interferon α.
Subcutaneous injection of interferon comes as a solution to be injected under the skin three times a week. You should inject this medicine on the same three days every week. The injections should be separated by a period of at least 48 hours. Interferon controls the symptoms of MS, but does not cure. The secondary effects are: dry eyes, feeling of dry mouth, upset stomach, vomiting, muscle stiffness, bruising, pain, inflammation or sensitivity in the place where you injected interferon.

2.     PACLITAXEL (TAXOL)
Taxol is a cancer medication that interferes with the growth of cancer cells and slows their growth and spread in the body. Taxol is used to treat several caners such as breast cancer, lung cancer, and ovarian cancer. It is also used to treat AIDS-related Kaposi's sarcoma.
Paclitaxel (TAXOL) was discovered in 1962 thanks to a National Cancer Institute located in the United States. This anti-cancer drug is produced by the needles of yew species by a sequence of 15 enzymatic steps from primary metabolism.
Paclitaxel is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.
You usually have paclitaxel as an injection into a vein. It can cause an allergic reaction, and to try to avoid this, you should have a steroid injection, pills, antihistamine, etc.
Common side effects are nausea and vomiting, An Increased risk of getting an infection from a drop in white blood cells, tiredness and weakness (fatigue) during and after treatment, loss of hair, mouth sores and ulcers, etc.


3.  INSULIN
The supply of insulin is needed to regulate glucose levels in patients with type 1 diabetes in all cases and occasionally in patients with type 2 diabetes, until the decade of the 80's it was obtained from the pancreas of cows or pigs, but it was in 1982 when the insulin produced by genetic engineering enters to the market, which now occupies 93% of the market.

Production takes place through a recombinant DNA, this involves creating a molecule of artificial DNA to produce a genetic modification that allows the addition of new features to the body, i.e., a recombinant protein that wasn´t on the organism appears. Currently, through this method, certain human proteins are cloned in suitable organisms for commercial production, including insulin.

The process begins with the identification and selection of the gene responsible for the production of insulin, then this is inserted in another organism that can be a bacterium, yeast or an animal cell, where the gene is cloned; for the manufacture of insulin it has been used the bacterium Escherichia coli or the yeast Saccharomyces cerevisiae. Then identical copies of the modified cells are stored and those that produce insulin in higher amounts are cultivated. Insulin obtained is mixed with other components to make the absorption more effective.

Human insulin, so named for being chemically identical to that produced naturally by our bodies, was the first recombinant protein that appeared on the market. Was developed by Genentech and distributed by Ely Lilly and Company in 1982 and became the first treatment of genetic engineering to be approved.




4.  THE GROWTH HORMONE
Human growth hormone is a protein hormone, called hGH, produced in the pituitary gland at the base of the brain mediating both growth and stature. It is a children's disease in which the pituitary malfunctions and secretes insufficient amounts of hGH for normal growth, which results in a non adequate growth so the child’s size will be lower than normal. This disease is called Hypopituitary dwarfism.

The growth hormone was first discovered in 1989 by Daniel Rudman. It experimented with elder people, just because the hGH is not just a hormone that makes you growth, but it also make bigger your muscles, some body fats were disappearing, etc. His patients had rejuvenate.

Those hormones are basically “chemical messengers”; substances which travel throughout the body, from an emitting organ to recipient one telling the message of growing to the body, but when it fails, doctors had to find a solution. Hypopituitary dwarfism was currently treated by administering hGH extracted from the pituitary glands of human cadavers, although hGH supplies were so limited and expensive that many suffering from hypopituitary dwarfism were unable to receive treatment and they had to find another solution. By genetic engineering, they were able to introduce inside bacteries the genetic information which contains the instructions of the manufacturing of this hormone. Bacteries are not affected and in some day they produce a really high amount of this hormone. They are evaluated and commercialize all around the world.

The production of these medicine by genetic engineering allows as to have really large ‘clean’ quantities which favours the transmission of the message and avoids secondary effects.



5.     HEPATITIS B VACCINE
The Hepatitis B vaccine is a vaccine developed for the prevention of infection by hepatitis B. The vaccine contains one of the envelope proteins of hepatitis B surface antigen of hepatitis B. After the Course Three doses injected, it is expected that the immune system developed antibodies against HBsAg Hague and are established in the bloodstream. The Formed antibody known as anti- HBsAg and provides immune memory against hepatitis B.
The vaccine was originally prepared from plasma obtained from patients with chronic infections of hepatitis B. However, in the present vaccines are manufactured using  recombinant DNA. These new vaccines were developed in 1986 by the Chilean biochemist Pablo Valenzuela. Both forms of the vaccine are considered equally effective. DNA vaccines consist of recombined proteins produced by genetically modified yeast cultures.
Infants born to mothers with active infections of hepatitis B should be vaccinated to reduce the risk of mother-to-child transmission of the virus. Immediately after birth, within the first 24 hours of birth, the newborn infants should be vaccinated with HBsAg and injected with anti-hepatitis B immunoglobulin (HBIg). The schedule of hepatitis B vaccine in infants vaccinated at birth includes a second dose a month or two months and a third dose at six months of age.


Jorge Rico, Álvaro Benito, Yousseff  Younes, Víctor Fernández, Lydia Soria y Laura Sánchez 4A


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