APPLICATION OF BIOTECHNOLOGY IN THE MEDICAL FIELD 

(1) Formation of Medicine

Medicine formed by rDNA technology is called Recombinant Medicine / Therapeutic Drugs.  Recombinant Medicines are pure, more efficient, and have fewer side effects. At present, about 30 recombinant therapeutics have been approved for human use the world over. In India, 12 of these are presently being marketed. 
e.g. of recombinant medicine(products)

  1. Human insulin-Diabetes  
  2. Growth hormone-Short Stature People 
  3. Calcitonin-Rickets
  4. Clotting factor VIII/IX-Haemophilla A/B 
  5. Interferon-Viral Infections, Cancer 
  6. Interleukin-Enhance Immune System   
  7. Tissue Plasminogen Activator (TPA)- Dissolving of blood clots
  8. Platelet-Derived Growth Factor-Stimulation of wound healing
  9. Vaccines-Hepatitis B, Influenza 

Formation Of Insulin

  • Proteineous Hormone contains 51 amino acids.
  • USE:- Control blood glucose level.
  • Deficiency:- Cause Diabetes Mellitus
  • Treatment:- Inject Insulin subcutaneously. 
  • Earlier, Insulin used for diabetes was extracted from the pancreas of slaughtered cattle and pigs.
  • Insulin from an animal source, caused some patients to develop allergies. 
  • So, Nowadays insulin produce by using rDNA techniques 


License to ncert 

A peptide-21 amino acids 
B peptide-30 amino acids 
C peptide-33 amino acids

Formation Of Insulin by r- DNA Technique


The main challenge for the production of insulin using rDNA techniques was getting insulin assembled into a mature form. In 1983 First recombinant insulin was produced by Eli Lilly (an American company). Eli Lilly prepared two DNA sequences corresponding to A and B, chains of human insulin, and introduced them in two different E. coli cells to produce insulin chains separately. Chains A and B were produced separately, extracted, and combined by creating disulfide bonds to form human insulin (named Humulin).

Gene Therapy 


Gene therapy may develop to treat some hereditary diseases such as SCID (Severe combined immunodeficiency), hemophilia, etc. Genes are inserted into a deceased person's cells and tissues to treat a disease. The first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency.  This enzyme is crucial for the immune system to function. The disorder is caused due to deletion or mutation of the gene for adenosine deaminase

ADA deficiency can be cured by- 
(a) Enzyme replacement therapy:- In which functional ADA enzyme is given to the patient by injection. (b) Bone marrow transplantation 
(c) Gene therapy 


APPLICATION OF BIOTECHNOLOGY IN THE MEDICAL FIELD 


A functional ADA gene (cDNA) (using a retroviral vector) is then introduced into lymphocytes, which are subsequently returned to (injected into) the patient. However, as these cells are not immortal, the patient requires the periodic infusion of such genetically engineered lymphocytes. However, if the functional ADA gene, isolated from marrow cells, producing normal ADA enzyme, is introduced into cells at early embryonic stages, it could be a permanent cure.

 

 Molecular Diagnosis

Using conventional methods of diagnosis (serum and urine analysis, etc.) early detection is not possible. Some of the techniques that serve the purpose of early diagnosis are:- 
(a) Polymerase Chain Reaction (PCR) 
(b) Recombinant DNA technology (using Probe) 
(c) Enzyme-Linked Immuno-sorbent Assay (ELISA) 


Polymerase Chain Reaction (PCR)

Very low concentration of a bacteria or virus (at a time when the symptoms of the disease are not yet visible) can be detected by amplification of their nucleic acid (genes) by PCR. PCR is now routinely used to detect HIV in suspected AIDS patients. It is being used to detect mutations in genes in suspected cancer patients too. It is a powerful technique to identify many other genetic disorders.


Recombinant DNA technology (using Probe) 



Probe:- A short, single-stranded DNA or RNA molecule, tagged with radioactivity. The probe is complementary to the normal gene. It binds to normal genes and is detected by autoradiography. The probe will not have complementarity with the mutated gene hence it will not bind to the mutated gene and will not appear on the photographic film (X-ray film) after autoradiography




Enzyme-Linked Immunosorbent Assay (ELISA) 


ELISA is based on the principle of antigen-antibody interaction. Infection by pathogens can be detected by the presence of their antigens (proteins, glycoproteins) or antibodies produced against them. 







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