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Stronger Reaction (stronger + reaction)
Selected AbstractsFunctional map and age-related differences in the human face: nonimmunologic contact urticaria induced by hexyl nicotinateCONTACT DERMATITIS, Issue 1 2006Slaheddine Marrakchi Variation in human skin reactivity to various irritants in association with age and body region has been reported. Hexyl nicotinate (HN), a lipophilic nicotinate ester, was used to induce nonimmunologic contact urticaria in human volunteers of 2 age groups: 10 young subjects [24,34 years, mean ± standard deviation (SD) 29.8 ± 3.9 years] and 10 older volunteers (66,83 years, mean ± SD 73.6 ± 17.4 years); and to define skin function and potential age-related differences in various facial areas. About 5 mM of HN in ethanol was applied to 8 locations on the face, neck, and volar forearm. A laser Doppler flowmeter was used to determine baseline blood flow and to monitor the skin blood flow changes after HN application. In the contralateral areas, stratum corneum turnover was determined using 5% dansyl chloride in petrolatum. In the young group, the perioral area exhibited the strongest reaction to HN. In the older group, the chin was the most sensitive site. In both the groups, the forearm was the least responsive. The older group demonstrated a stronger reaction than the younger group in 3 sites (forehead, cheek, and nasolabial area). Stratum corneum turnover was slower in the nasolabial area and in the forearm in both age groups, whereas the fastest was in the perioral area and the chin in the younger group and in the chin and the forehead in the older group. Compared to the older group, the younger group showed a slower stratum corneum turnover in the nose and the neck. This study demonstrates the regional and the age-related variability of the stratum corneum turnover and the skin reactions to HN. These observations may help explain some aspects of the cutaneous intolerance in skin care of the face. [source] Taxon-specific reaction norms to predator cues in a hybrid Daphnia complexFRESHWATER BIOLOGY, Issue 7 2007JUSTYNA WOLINSKA Summary 1. Previous studies have shown that interspecific hybridisation is common among taxa from the Daphnia galeata/hyalina/cucullata species complex. We investigated the influence of predator kairomones on the morphology and life histories of nine clones belonging to three taxa (pure D. galeata, F1 hybrids between D. galeata and D. hyalina, and backcrossed D. hyalina) of this species complex. Predators exerting positive (fish) and negative (Chaoborus larvae) size-selective predation were tested. 2. The most responsive traits were size at maturity and size of neonates. Despite large between-clone variation, discriminant analysis revealed that the three taxa were distinct from each other in key life-history traits. F1 hybrids did not react in an intermediate way compared to the other taxa: the multivariate distances between F1 hybrids and either taxon were larger than between pure D. galeata and backcrossed D. hyalina. 3. The average plasticity (calculated across all traits) was similar for all three taxa. With regard to the size at maturity and neonate body size, the strength of the response was a function of the intrinsic values of these traits expressed in the control. For example, for size at maturity, smaller individuals showed a significantly stronger reaction to Chaoborus kairomones than larger ones. 4. Finally, we monitored seasonal changes in body size, egg number and population density of pure D. galeata and F1 hybrids in Greifensee (Switzerland). The two taxa experienced similar seasonal changes in body size but, on some sampling dates, they differed in mean egg number. The observed seasonal changes in Daphnia body size were consistent with what would be expected if the predator assemblage shifted from fish to Chaoborus over the course of the summer. The fluctuations in the frequencies of Daphnia taxa, however, were not related to seasonal variation in Daphnia body size. 5. Experimental data suggest that temporally heterogeneous predation regimes might be an important condition stabilising the co-occurrence of Daphnia hybrids with parental taxa. Predation regimes, however, cannot solely explain dynamic changes in taxon frequency in Greifensee. [source] Predator-induced life-history changes and the coexistence of five taxa in a Daphnia species complexOIKOS, Issue 1 2000Piet Spaak Interspecific hybridization is common in water fleas of the Daphnia galeata species complex (e.g. D. galeata, D. cucullata, D. hyalina and their interspecific hybrids). We studied the effect of fish on the life histories of five taxa of this species complex originating from the Plußsee, northern Germany. Using four clones per taxon, we found that fish kairomones reduce size at birth and size at maturity significantly. For size at maturity larger taxa showed a significantly stronger reaction to fish kairomones than the smaller taxa. With respect to the intrinsic rate of increase, r, we compared two predation regimes (positive size selective and not selective). We found that under the fish predation regime most clones had a higher r when cultured with fish kairomones, leading to a higher r, and a stronger reaction for the smaller taxa. We conclude that fish predation might be an important factor influencing the co-occurrence of Daphnia parental taxa with their hybrids. [source] Relationship between formaldehyde and quaternium-15 contact allergy.CONTACT DERMATITIS, Issue 4 2010Influence of strength of patch test reactions Background: In groups of patients with formaldehyde allergy, many have positive patch tests to quaternium-15. Conversely, of patients allergic to quaternium-15, over half also react to formaldehyde. Objectives: To test our hypothesis that patients with stronger patch test reactions to formaldehyde are more likely to react to quaternium-15, attesting to the aetiological role for formaldehyde in such co-reactivity. Methods: Retrospective analysis of all patients patch tested with formaldehyde and quaternium-15 in the European baseline series between 1994 and 2009 (TRUE test®). Results: In a group of 86 patients allergic to formaldehyde, 73% co-reacted to quaternium-15; in the subgroup of 70 women, the percentage was 83. In both groups, more reactions were observed to quaternium-15 in the patients with a ++ reaction compared to the patients with a + reaction to formaldehyde. Conversely, stronger reactions to quaternium-15 were significantly more often associated with formaldehyde sensitivity in a group of 107 patients reacting to quaternium-15 and a subgroup of 88 women. In men, such effects were not observed and only 5 of 16 (31%) men allergic to formaldehyde also reacted to quaternium-15. Conclusions: In women, but not in men, stronger reactions to formaldehyde lead to more positive quaternium-15 patch tests. [source] Men's and women's reactions to fair and unfair treatment in relationship conflictPERSONAL RELATIONSHIPS, Issue 4 2009ESTHER S. KLUWER Evidence of gender differences in reactions to experienced fair and unfair treatment in relationship conflict was examined in 4 studies among dating, cohabiting, and married participants in The Netherlands. Using a critical incidents method and a scenario, this research provided convergent results suggesting that the relationship between fairness of treatment and affective feelings or relationship satisfaction is stronger for women than for men. This gender difference disappeared under conditions of high relationship commitment. Furthermore, men who identified strongly with their relationship showed stronger reactions to fair treatment than men who identified weakly with their relationships. Finally, the manipulation of relationship salience led to heightened sensitivity to fairness of treatment among men, but not among women. [source] | ||||||||||