Weekly hair washing: The recommended solution for women with afro-textured hair to alleviate dandruff and scalp discomfort.

Dandruff and scalp discomfort are common concerns for women and men in Africa. Moreover, women with afro-textured hair are prone to scalp discomfort owing to irregular hair washing, frequent use of oil-based products on their scalp, and harsh chemical treatments. Current literature does not, however, provide data on the pathophysiological mechanisms of these conditions in this population. In this study, we investigated the mechanisms behind scalp discomfort and dandruff in women of African descent before and after hair washing. We conducted the in Durban, South Africa, over a 3-week period with 60 women of African descent aged 20-40 years. The respondents were equally divided into a "dandruff" and a "no dandruff" group, based on clinical grading of adherent dandruff by a dermatologist. Malassezia spp. and bacterial loads were quantified by quantitative polymerase chain reaction. Evaluations of scalp condition and sample collection were performed at five time points during the 3 weeks. Data on discomfort symptoms were collected via a self-assessment questionnaire. We observed that the dandruff severity peaked at the end of the first week after hair washing and plateaued from thereon in both groups. Dandruff was associated with higher Malassezia and bacterial load counts and there was a direct correlation between the Malassezia spp. load and dandruff score. Via self-assessment questionnaire responses submitted by participants, we observed that itching was the most pronounced scalp discomfort, compared with the sensation of tingling and burning at baseline, while an improvement of the scalp symptoms of dandruff and itch was observed in both groups after one hair wash. The study also showed that higher colonization with Malassezia spp. and bacteria is associated with dandruff independently of the time point, confirming a scalp microbiome contribution to the dandruff pathophysiology in the study population. The benefits of washing were, however, not sustained after 1 week and we thus recommend weekly hair washing for long-term management of dandruff and scalp itchiness in this population.

Testate amoebae (Arcellinida, Amoebozoa) community diversity in New England bogs and fens assessed through lineage-specific amplicon sequencing.

Testate amoebae (order Arcellinida) are abundant in freshwater ecosystems, including low pH bogs and fens. Within these environments, Arcellinida are considered top predators in microbial food webs and their tests are useful bioindicators of paleoclimatic changes and anthropogenic pollutants. Accurate species identifications and characterizations of diversity are important for studies of paleoclimate, microbial ecology, and environmental change; however, morphological species definitions mask cryptic diversity, which is a common phenomenon among microbial eukaryotes. Lineage-specific primers recently designed to target Arcellinida for amplicon sequencing successfully captured a poorly-described yet diverse fraction of the microbial eukaryotic community. Here, we leveraged the application of these newly-designed primers to survey the diversity of Arcellinida in four low-pH New England bogs and fens, investigating variation among bogs (2018) and then across seasons and habitats within two bogs (2019). Three OTUs represented 66% of Arcellinida reads obtained across all habitats surveyed. 103 additional OTUs were present in lower abundance with some OTUs detected in only one sampling location, suggesting habitat specificity. By establishing a baseline for Arcellinida diversity, we provide a foundation to monitor key taxa in habitats that are predicted to change with increasing anthropogenic pressure and rapid climate change.

Reduction of wrinkles: From a computational hypothesis to a clinical, instrumental, and biological proof.

BACKGROUND: Facial wrinkles are clear markers of the aging process, being chronological, photo-induced, or reflecting repetitive facial expressions. The aim of this study is to provide new insights into the biophysical and biological mechanisms involved in the formation, prevention, or elimination of the expression wrinkles. MATERIALS AND METHODS: We use a computational model to get a better understanding of the wrinkle mechanical behavior and evolution after skin softening and suggesting a possible antiaging mechanism. Then, we provide a clinical demonstration of the anti-wrinkle effect of a long-term application of a 20% glycerol in a moisturizer formula (GBM) versus its vehicle on crow's feet. Skin hydration, elasticity, and wrinkles visibility were evaluated by a combination of clinical and instrumental in vivo data, inverse finite element analysis, and proteomic data. RESULTS: The computational model shows a predominantly compressive stress beneath the wrinkle and its significant decrease by the softening of stratum corneum. The associated clinical study confirmed a significant increase of skin hydration and elasticity as well as a decrease of wrinkle visibility after 2 and 4 months as application for both formulas; this effect being stronger for GBM. A softening effect on stratum corneum and dermis was also observed for the GBM. Furthermore, proteomic data revealed an effect of upregulation of four proteins associated with desquamation, cell-glycan extracellular interactions, and protein glycation/oxidation, functions related to the tissue mechanics and adhesion. CONCLUSIONS: We provide an in vivo demonstration of the anti-ageing benefit of glycerol at high dose (20%) reflected by a cumulative skin surface softening effect. The use of high moisturizing potent formulations should bring additional performance to other conventional moisturizing formulations.

In-Vivo Tape Stripping Study with Caffeine for Comparisons on Body Sites, Age and Washing.

PURPOSE: Assessing the percutaneous absorption of cosmetic ingredients using in-vitro human skin reveals certain limitations, such as restricted anatomical sites and repeated exposure, and to overcome these issues, in-vivo studies are required. The aim of the study is to develop a robust non-invasive in-vivo protocol that should be applicable to a wide range of application. METHODS: A robust tape stripping protocol was therefore designed according to recent recommendations, and the impact of two different washing procedures on caffeine distribution in tape strips was investigated to optimise the protocol. The optimised protocol was then used to study the effect of age and anatomical area on the percutaneous absorption of caffeine, including facial areas which are not readily available for in-vitro studies. RESULTS: With tape stripping, a difference between the percutaneous absorption on the face (forehead, cheek) and the volar forearm was observed. No obvious difference was observed between percutaneous absorption in young and post-menopausal women, but this could be due to the limited number of subjects. CONCLUSION: This tape stripping protocol is now to be deployed to address many other factors, such as percutaneous absorption in other anatomical areas (e.g. abdomen, axilla, etc.), impact of repeated applications and effect of formulation.