RESUMEN
Itching is a prominent clinical manifestation of sensitive skin; it reduces cutaneous barrier function, mainly caused by dryness. Scratching to relieve itching destroys the skin barrier, thus forming the itch-scratch cycle that results in additional disruption of skin barrier and chronic itching. Treatment involves alleviation from itching for sensitive skin. Recently, substance P (11-amino acid neuropeptide of the tachykinin family) and neurokinin 1 receptor (NK1R) have been considered to provide a key pathway to treat chronic itching. A single-center, open-label study was conducted comprising subjects with dry, itchy, and sensitive skin to evaluate the efficacy of two types of itch-relief moisturizers, mist and lotion, containing maltotetraose (MTO). In all, 35 subjects used mist containing MTO, resulting in significant improvement in itch score from 1 minute to 2 hours following single application. On the other hand, 34 subjects applied lotion containing MTO for 1 week, resulting in significant improvement in itch score, skin hydration, and clinical scores of erythema/redness and dryness; however, in both cases, improve-ment was not observed in the measurement of transepidermal water loss (TEWL). It was concluded that two types of itch-relief moisturizers containing MTO were effective for dry, itchy, and sensitive skin.
Asunto(s)
Prurito , Humanos , Prurito/tratamiento farmacológico , Prurito/etiología , Femenino , Masculino , Adulto , Persona de Mediana Edad , Crema para la Piel/administración & dosificación , Emolientes/administración & dosificación , Emolientes/uso terapéutico , Adulto Joven , Anciano , Resultado del Tratamiento , Pérdida Insensible de Agua/efectos de los fármacos , Oligosacáridos/administración & dosificación , Administración CutáneaRESUMEN
Arbuscular mycorrhizal (AM) fungi form mutualistic, symbiotic associations with the roots of more than 80% of land plants. The fungi are incapable of completing their life cycle in the absence of a host root. Their spores can germinate and grow in the absence of a host, but their hyphal growth is very limited. Little is known about the molecular mechanisms that govern signalling and recognition between AM fungi and their host plants. In one of the first stages of host recognition, the hyphae of AM fungi show extensive branching in the vicinity of host roots before formation of the appressorium, the structure used to penetrate the plant root. Host roots are known to release signalling molecules that trigger hyphal branching, but these branching factors have not been isolated. Here we have isolated a branching factor from the root exudates of Lotus japonicus and used spectroscopic analysis and chemical synthesis to identify it as a strigolactone, 5-deoxy-strigol. Strigolactones are a group of sesquiterpene lactones, previously isolated as seed-germination stimulants for the parasitic weeds Striga and Orobanche. The natural strigolactones 5-deoxy-strigol, sorgolactone and strigol, and a synthetic analogue, GR24, induced extensive hyphal branching in germinating spores of the AM fungus Gigaspora margarita at very low concentrations.