Monday, 12 May 2014

Medicines obtained by genetically modified organisms


The ability to manipulate and transform the genes between the bacteria, plants, animals and insects has created many new organisms modified genetically.

Nowadays we can cultivate more resistant vegetables to viruses and insects, or bigger and cheaper fruits that don’t need insecticides. But the most interesting use of the genetically modified organisms is the ability of fight against diseases and supply specific substances to persons with a deficiency.
For example, there are proteins with a composition or modifications not founded in plants due to the lack of mechanisms for creating them. On the other hand, transgenic plants have shown a great capacity to produce antibodies.

Those antibodies are used in the diagnosis and treatment of some kinds of cancers and many viruses like the hepatitis, the hydrophobia and the cytomegalovirus. Tobacco, potato, maize, soy and rice plants have been modified to produce tons of those proteins.  


Different phases on the testing of genetically modified medicines.

Phase I:
The testing in phase I involves the first time that the medicine is studied on human beeins, the goal consist in the evaluation of security, tolerability and the time that the medicine has an effect on the body before being metabolized.
In these phase around 20 people are tested (They aren’t normally affected by the illness)

Phase II:
In this phase the goal is to determine the efficiency and security of the medicine.
More people are needed in this phase, and the ones that are tested usually suffer the illness.
Most of the new medicines fail in this phase due to problem in security.

Phase III:
The purpose of this phase is to confirm the efficiency of the medicine and compared it with other treatments that have already being commercialized.
Hundreds or even thousands of people have to be studied and this study can last for two or three years.
- If the phase III is finalized with success the promoter company will present a request to the sanitary authorities, and if the request is approve the medicine can be produced, commercialized and sell in the countries that follow the sanitary rules of the authorities that approved the medicine.

Phase IV:
The testing processes of phase IV take place when the medicine has already been commercialized, Million of people are tested and many time adverse reaction are found so the medicine has to be taken away.
Insulin is a hormone which controls the anabolism of glucose. Diabetes is a group of illnesses in which the sufferers have high blood sugar. It can be due to a lack of production of insulin or because the cells of the body do not respond properly to the insulin that is produced.

Thanks to insulin shots, people suffering for diabetes can have normal lives. In the past, insulin from cows or other mammals was used, which actually isn’t exactly the same as human insulin. Nowadays, genetically modified bacteria are used. Human insulin derived from bacteria is the first clinically proven product of recombinant DNA technology. For developing the genetically modified bacteria:
1st, two separate bacterial strains were constructed. One chain contained a gene for the A-chain of human insulin and the other chain carried a gene for the B-chain of human insulin.
2nd Inside the bacteria, insulin chains are made as tails on a precursor protein
3rd The insulin chains are clipped from the protein, in vitro, with  cyanogen bromide
4th The separate insulin chains are joined to give complete, active insulin

Genetic vaccines.

Used genetically modified organism to produce antigens. The antigens are used to create a new vaccine. This process can be summarized in the following steps:
1. The identification and the insolation of the pathogenic agent.
2. The identification of the producer gen of the antigen the pathogenic agent.
3. The introduction of this gen in the genome of a bacteria and the reproduction of that bacteria genetically modified.
4. The production of the search proteins (by the colony of genetically modified bacteria).
5. The extraction and the isolation from the medium of the cultivation of those proteins.
6. the injection of the protein, from vaccines, for the generation of the immunization  facing that pathogen.
Example in a human person:
biolo (2).png
The creation of transgenic mosquitos against the dengue fever.
In Brazil there are a lot of mosquitos that transmit the dengue fever. This fever hasn't got any treatment this fever can produce fever, headache, muscle pain, gastric juices and in serious cases produce the death, and because of that the brazilian government have done some things.
To solve this serious problem some biologist have create a variation of the mosquito, all of them are males, they have modified the genes of the sperm, for the eggs not to born.
They modified the sperm to the eggs need to eat tetracycline and the mum can not provide that so the mosquitos finally dead.
With that measurements the population of mosquitos decrease a lot and this is directly connected to less beats of mosquitos and less people would be infected with the dengue fever.
They have freed 500 mosquitos per resident of Brazil this means that almost all the population of infected mosquitos would be disappear.  

Daniel Fenandez, Juan Gil, Asier Lopez, Elena Mendez, Yolanda Chamoso. 4ºA

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