PubMed HealthSearch

PubMed · 58944

What can be measured with RAST?

Abstract

A theoretical study of the basic principles involved in Radioallergosorbent test (RAST) showed that: 1) When a given serum is tested, the significance of the numerical value obtained with RAST depends upon the serum assayed and the allergosorbent preparation, in a rather unpredictable way. Three factors can be measured: a) The percentage of specific IgE antibodies among all allergen-specific antibodies; b) The specific IgE antibody level; c) The product of the specific IgE antibody level and its affinity constant. 2) Simple graphical techniques allow a straightforward determination of all these factors if four dilutions of each serum are assayed at the same time. The results are expressed in two constant parameters (arbitrary IgE unit and allergosorbent capacity). It is concluded that these theoretical calculations may give a fair account of a lack of correlation between specific IgE antibody levels (as assayed with RAST) and several clinical and biological parameters. Furthermore, they provide a simple procedure which makes such tedious manipulations as specific IgE antibody purification quite necessary.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

P Bongrand, D Vervloet, R Depieds, J Charpin. 1976. What can be measured with RAST?. https://doi.org/10.1016/0022-1759(76)90113-7

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Systemic absorption and sustained effects of vaginal estrogen creams.

Systemic absorption and sustained effects of two estrogen vaginal cream preparations (Premarin and Estrace) were measured in 29 postmenopausal women receiving daily applications. With both preparations, vaginal absorption of estrogens into the systemic circulation was rapid, efficient, and sustained. It is apparent that estrogen vaginal cream preparations, as widely used in clinical practice for their local effects on the vaginal mucosa, actually result in sustained high estrogen levels in the systemic circulation. The vaginal route shows promise when systemic estrogen therapy is indicated, but is dangerous when estrogen is contraindicated.

Absorption

Effect of amiloride on the apical cell membrane cation channels of a sodium-absorbing, potassium-secreting renal epithelium.

The effect of the K-sparing diuretic amiloride was assessed electrophysiologically in the isolated cortical collecting tubule of the rabbit, a segment which absorbs Na and secretes K. Low concentrations of amiloride in the perfusate caused a rapid, reversible, decrease in the magnitude of the lumen negative transepithelial potential difference, Vte, transepithelial conductance Gte, and equivalent short-circuit current, Isc, with an apparent K1/2 of approximately 7 X 10(-8) M. The effects of a maximum inhibitory concentration of amiloride (10(-5) M) were identical to those observed upon Na removal from lumen and bath (Na removal from the bath alone has no effect). Removal of Na in the presence of 10(-5) M amiloride had no affect on Vte, Gte, or Isc, and is consistent with the view that amiloride blocks the Na conductive pathways of the apical cell membrane. Further, in the absence of Na, the subsequent addition of amiloride had no influence. In tubules where active Na absorption was either spontaneously low, or abolished by removal of Na from lumen and bath, the elevation of K from 5 to 155 meq/liter in the perfusate caused a marked change of the Vte in the negative direction and an increase in the Gte. These effects could be attributed to a high K permeability of the apical cell membrane and not of the tight junctions. Amiloride (10(-5) M) had no effect on these responses to K. It is concluded that amiloride selectively blocks the apical cell membrane Na channels but has no effect on the K conductive pathway(s). This selective nature of amiloride may indicate that Na and K are transported across the apical cell membrane via separate conductive pathways.

Absorption