Modulators are split into two classes: potentiators and correctors. Potentiators act on the CFTR ion channels that are embedded in the cell membrane, and these types of drugs help open up the channel to allow transmembrane flow. Correctors are meant to assist in the transportation of nascent proteins, a protein that is formed by ribosomes before it is morphed into a specific shape, to the cell surface to be implemented into the cell membrane.Most target the transcription stage of genetic expression. One approach has been to try and develop medication that get the ribosome to overcome the stop codon and produce a full-length CFTR protein. About 10% of CF results from a premature stop codon in the DNA, leading to early termination of protein synthesis and truncated proteins. These drugs target nonsense mutations such as G542X, which consists of the amino acid glycine in position 542 being replaced by a stop codon. Aminoglycoside antibiotics interfere with protein synthesis and error-correction. In some cases, they can cause the cell to overcome a premature stop codon by inserting a random amino acid, thereby allowing expression of a full-length protein. Future research for these modulators is focused on the cellular targets that can be effected by a change in a genes expression. Otherwise, genetic therapy will be used as a treatment when modulator therapies do not work given that 10% of people with cystic fibrosis are not affected by these drugs.Elexacaftor/ivacaftor/tezacaftor was approved in the United States in 2019 for cystic fibrosis.
Pallor is a pale color of the skin that can be caused by illness, emotional shock or stress, stimulant use, or anemia, and is the result of a reduced amount of oxyhaemoglobin and may also be visible as pallor of the conjunctivae of the eyes on physical examination. Pallor is more evident on the face and palms. It can develop suddenly or gradually, depending on the cause. It is not usually clinically significant unless it is accompanied by a general pallor (pale lips, tongue, palms, mouth and other regions with mucous membranes). It is distinguished from similar presentations such as hypopigmentation (lack or loss of skin pigment) or simply a fair complexion. Causes
migraine attack or headache
excess estradiol and/or estrone
osteoporosis
emotional response, due to fear, embarrassment, grief, rage
anorexia
anemia, due to blood loss, poor nutrition, or underlying disease such as sickle cell anemia
iron deficiency
vitamin B12 deficiency
shock, a medical emergency caused by illness or injury
acute compartment syndrome
frostbite
common cold
cancer
hypoglycaemia
bradycardia
panic attack
medications
ketorolac
amphetamines
ethanol
cannabis
lead poisoning
motion sickness
heart disease
Peripheral vascular disease
hypothyroidism
hypopituitarism
scurvy
tuberculosis
sleep deprivation
pheochromocytoma
squeamishness
visceral larva migrans
Orthostatic hypotension
methyldopa
loss of appetite
Space adaptation syndrome
fibromyalgia
Buergers disease
Hypovolemia

References


== External links ==