For testing with sodium lauryl sulphate (SLS), measurements of transepidermal water loss (TEWL) and cutaneous blood flow with laser Doppler (LD) are considered to be the most reliable methods. The aim of this study was to determine which method of measurement should be preferred when conducting SLS testing under varying conditions. Patch testing with SLS at different concentrations and exposure times was performed. TEWL values were compared with those of LD. TEWL values showed distinct changes at low SLS concentrations and short application periods. By contrast, higher SLS concentrations were necessary to increase LD values. Short application of patches changed TEWL rather than LD values. When evaluating SLS patch testing by bioengineering methods, TEWL measurement appears to be more suitable for a test procedure that provokes mild skin reactions (SLS concentration <1%), whereas LD measurement is more appropriate to evaluate pronounced skin reactions (SLS concentration >or=1%).
Only one report has described the ethanolinduced release of vasoactive intestinal polypeptide (VIP), and its mechanism of action is unknown. We studied changes in mesenteric immunoreactive VIP (IR-VIP) concentrations following the intrajejunal administration of 100 ml of normal saline, 5% and 10% ethanol, and hypertonic saline which was isoosmolar to 10% ethanol (1,670 mOsm/liter) in dogs. Administration of 5% and 10% ethanol resulted in significant and dose-dependent increases in mesenteric IR-VIP. Mesenteric IR-VIP changes and incremental integrated responses to 10% ethanol and to hypertonic saline were the same. We concluded that ethanol-induced VIP release in dogs is mainly due to ethanol's hyperosmolarity.VIP ; mesenteric vein ; ethanol ; hyperosmotic saline ; osmotic pressure Vasoactive intestinal polypeptide (VIP) is distributed throughout the gastrointestinal tract (Yanaihara et al. 1977;Fahrenkrug 1979) and nervous system (Said and Rosenberg 1976) and has a broad spectrum of biological activities. VIP's main role as a neurotransmitter in the gastrointestinal tract is the relaxation of smooth muscle and increase of blood flow. Several investigators have reported VIP-releasing factors (Schaffalitzky de Muckadell et al. 1977a ;Bloom et al. 1978 ; Chayvialle et al. 1980a, b). Only the report by Schaffalitzky de Muckadell et al. (1977b) has shown a VIP-releasing effect of ethanol, and no report has demonstrated a mechanism of VIP release by ethanol. This study investigated the VIP response to intrajejunal ethanol administration by measuring IR-VIP concentrations in the jejunal mesenteric vein.
MATERIAL AND METHODSSixteen male mongrel dogs (weight, 13-18 g) were fasted for 24 hr. Anesthesia was induced by thiopental sodium (30 mg kg) and maintained by barbital sodium (250 mg/kg).
Skin irritation is mostly a multifactorial process. Competitive effects of different chemical irritants are well known. This study investigates the influence of a thermal stimulus on skin pre-irritated with sodium lauryl sulfate (SLS). Seventy-seven volunteers were patch-tested with SLS 0.25% and 0.5% for 48 h. Water served as control. Skin reaction was evaluated by measurement of transepidermal water loss, skin blood flow and skin color. After measurement, a thermal stimulus was applied on the test area. The increase in skin blood flow was measured. There was a significant correlation between the degree of irritation and the increase in skin blood flow after thermal stimulus. Pre-irritated skin reacted to thermal stimulus with a shorter and sharper increase in skin blood flow. This increase was dependent on the SLS concentration. Hence, the thermally stimulated blood flow may be a model of non-chemical irritation and seems to be a relevant co-factor in the pathogenesis of irritant dermatitis.
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