Dear Mindy....
aiya.. actually i tink S'pore's syllabus might be too simple for u lol.. but nvm i shall juz type some stuff ok x) anyway wat i haf is time
Cystic Fibrosis(CF) is a genetically inherited disease in which the chloride transport is the rooot cause of its symptoms. Althought most people without CF haf 2 working copies of the cystic fibrosis transmembrane conductive regulator (CFTR) gene (its a gene that produces that codes for the protein) only one is needed to prevent cystic fibrosis. CF develops when neither gene works normally. Therefore CF is considered an autosomal recessive disease.
Some symptoms:
-Excessively salty sweat, chloride being a main component (NaCL)
-Abnormal heart rhythms
-Thick mucus which amasses in the lungs and intestines.
-Respiratory infections (complications can lead to death)
-abdominal pain n poor weight gain
The disease is caused by an alteration in a single gene on chromosome no. 7, responsible for producing a protein (CFTR protein) that regulates transmembrane conductance.
In CF patients, this gene has a mutation: the deletion of the 3 nucleotides resulting in a loss of a single amino acide (phenylalanine at position 508)
2 possible outcomes for a defective CFTR (the protein)
-Defect is detected in the endoplasmic reticulum ( it is responsible for protein synthesis and insertion of proteins into the cellular membrane) and is marked for degradation, never making it to the cell membrane. This type of CF is most common.
-Some CF patients are able to produce CFTR that is inserted into the cell membrane. However the protein still malfunctions due to disruptions in the function of the nucleotide binding site. One such mutation in CFTR alters the amount of time the channel stays open, making it so that the protein closes at a faster rate than that of a normal CFTR.
Where can Mindy find the CFTR protein??
-Epithelial cells lining the surfaces of exocrine glands (u shud noe wat it is rite?)
-epithelial cells lining the airways.
- The CFTR proteiun acts as a chliride ion channel. It also has some influence and effect on other types of chloride cion channels as well as sodium ion channels.
2 pathological processes in patients
1) At the lungs/respiratory tract and digestive tract:
-Lumen can become obstructed by viscous mucus. An imbalance in the transport of chloride ions out of epithelial cells results in the improper transport of sodium ions. The incorrect movement of these ions leads to the cells absorbing more water than normal. This is seen wihtin the pancreas, gastrointestinal tract, bile ducts and some salivary glands.
-The mucus produced is in excess and of the wrong consistency. (seen in airways)
2) At the sweat glands
-Patients secrete high levels of salt in their sweat, putting them at risk of dehydration.
-Process:
- Sodium and chloride ions travel freely into the gland from the bloodstream.
-Water moves into the gland to minimize the gland of sodium and chloride ions built up inside.
-In a normal gland, the sodium and chloride ions leave the gland through separate channels back to the bloodstrea,. where they are reabsorbed.
-Water is excreted onto the skin surfaces as sweat
-Cystic fibrosis cripples this process
-Sodium and chloride ions still enter the glands and the water follows, but the CFTR cannot provide transport fo the chloride ions to go back thru the gland's membrane.
-The sodium channel is operations but the charged ions keep an equilibrium in the gland. Therefore, sodium is retained with the chloride in the gland.
The body loses high levels of salt as an unnatural amt is deposisted onto the skin with water in the form of sweat...
Some cures via gene therapy
1) adenovirus.. naturally affects lungs and most effective for delivering gene but triggers and immune response
2) or u could use its good friend adeno-associated virus (AAV) does not produce an immune response but more research is needed. It carries small amount of foreign DNA with it and is replicates using the adenovirus bring about issues of purity.
3) liposomes.. not as effective
this is only A level standard... haha i tink ur uni standard is MUCH HIGHER!! esp US
ehh mindy i need help i need a dress for grad nite.. tell me wat i shud wear!!!
i watched stardust yest.. OMG shud a beautiful show.. sigh.. they leaved happily together forever as stars in the sky.. because he won the heart of a star X)
awwww.... hiazz can't wait for uraina poh to come back.. meantime im SUPPOSE to go to some club with de roza n bridget... haven decided.. ZZZzzZZzz......
"The wise men in the storm prays to God, not for safety from danger, but for deliverance from fear." Ralph Waldo Emerson