Irritation variables influencing

The effect of a surfactant on skin depends on the type of surfactant as described earlier. Wilhelm et al. demonstrated the irritation potential of anionic surfactants.21 They evaluated the effects of sodium salts of n-alkyl sulfates with variable carbon chain length on TEWL and found that a C12 analog gave a maximum response. They suggested that the mechanisms responsible for the hydration of SC are related to the irritation properties of the surfactants. Leveque et al. also suggested22 that the hyperhydration of SC is consecutive to the inflammation process. They demonstrated that the increase of TEWL was induced by SDS without removal of SC lipids. SDS might influence not only SC barrier function, but also the nucleated layer of epidermis and dermal system associated with inflammation.23 Recently, no correlation was found between the level of epidermal hyperplasia and TEWL increase on the SDS-irritated skin.23 Further work would be needed to determine the effects of surfactants on skin. 

Increased eosinophil concentration and increased levels of albumin and total protein have been found in nasal lavage fluid taken from subjects exposed to 0.4 ppm formaldehyde for 2 hours (Krakowiak et al. 1998 Pazdrak et al. 1993). Although these variables are not expected to be only influenced by formaldehyde, they appear to be promising biomarkers of acute respiratory irritation from airborne formaldehvde. 

Various methods have been published to examine nasal lavage fluid for cellular and chemical contents that may be indices of acute allergic or inflammatory responses to formaldehyde or other respiratory irritants (Pin et al. 1992 Prat et al. 1993 Wang et al. 1995). Increased eosinophil concentration and increased albumin and total protein levels have been found in nasal lavage fluid taken from subjects exposed to 0.4 ppm formaldehyde for 2 hours (Krakowiak et al. 1998 Pazdrak et al. 1993). Although these variables are not expected to be specifically influenced by formaldehyde, they appear to provide biomarkers of acute respiratory irritation from airborne formaldehyde or other upper respiratory irritants. Further research on relationships between concentrations of these variables in nasal lavage fluid and prevalence or severity of respiratory symptoms in humans exposed acutely to varying concentrations of formaldehyde may help to confirm their use as biomarkers of effect. 

---