Kaulbach H C, White M V, Igarashi Y, Hahn B K, Kaliner M A
Allergic Diseases Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda 20892.
J Allergy Clin Immunol. 1993 Sep;92(3):457-65. doi: 10.1016/0091-6749(93)90125-y.
The luminal surface of respiratory mucous membranes is lined with an epithelial lining fluid (ELF) layer. Previous attempts to determine ELF volumes in airways have used dyes or freely diffusible molecules such as urea, yet have not led to a universally accepted method. The nasal mucous membrane provides an accessible area to examine whether urea is an appropriate marker of respiratory ELF volume.
Collection of undiluted nasal secretions after either glandular stimulation or induction of vascular permeability confirmed that plasma urea and nasal urea concentrations are equivalent. Baseline ELF volume was calculated as 800 microliters/nostril. The calculated molar concentrations of urea in ELF did not vary with either methacholine or histamine challenge.
These data indicate the plasma, interstitial, glandular, and ELF urea concentrations are equivalent and, therefore, that urea is a useful marker of ELF volume in the nasal mucosa.
呼吸道黏膜的腔面衬有一层上皮衬液（ELF）。以往测定气道中ELF容量的尝试使用了染料或尿素等可自由扩散的分子，但尚未形成一种被普遍接受的方法。鼻黏膜提供了一个可用于检验尿素是否为呼吸道ELF容量合适标志物的可及区域。
在腺体刺激或诱导血管通透性后收集未稀释的鼻分泌物，证实血浆尿素和鼻尿素浓度相等。基线ELF容量计算为每侧鼻孔800微升。计算得出的ELF中尿素的摩尔浓度在乙酰甲胆碱或组胺激发试验中均无变化。
这些数据表明血浆、间质、腺体和ELF中的尿素浓度相等，因此尿素是鼻黏膜中ELF容量的有用标志物。
