Do brine shrimp diagnose cystic fibrosis?.

The nauplii of the brine shrimp Artemia salina are dependent upon the 
function of their salt gland to maintain osmotic pressure within narrow 
limits. A number of drugs interfere with this function and are 
lethal to the nauplii. Saliva and serum from normal persons, patients 
with cystic fibrosis, and obligate heterozygotes were tested for lethal effect 
against brine shrimp nauplii. At salt concentrations between 100 mM and 
2.5 no difference was found among the phenotypes. At lower concentrations 
a difference was noted occasionally between some normal subjects and some 
individuals carrying one or two genes for cystic fibrosis. Data from 
an independent series of experiments indicate that the naupliar deaths result 
from distorted ratios of Na+/K+ and not from a specific gene 
product. No difference was noted in the O2 uptake of nauplii 
treated with saliva or serum obtained from normal subjects, patients with 
cystic fibrosis, or obligate heterozygotes. 