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1. Screening sunscreens: protecting the biomechanical barrier function of skin from solar ultraviolet radiation damage

   https://doi.org/10.1111/ics.12370  

   Berkey, C. ; Biniek, K. ; Dauskardt, R. H. ( October 2016 , International Journal of Cosmetic Science)

   Solar ultraviolet (UV) radiation is ubiquitous in human life and well known to cause skin damage that can lead to harmful conditions such as erythema. Although sunscreen is a popular form of protection for some of these conditions, it is unclear whether sunscreen can maintain the mechanical barrier properties of skin. The objective of this study was to determine whetherin vitrothin‐film mechanical analysis techniques adapted for biological tissue are able to characterize the efficacy of commonly used UV inhibitors and commercial sunscreens to protect the biomechanical barrier properties of stratum corneum (SC) from UV exposure.

   The biomechanical properties of SC samples were assayed through measurements of the SC's drying stress profile and delamination energy. The drying stresses within SC were characterized from the curvature of a borosilicate glass substrate onto which SC had been adhered. Delamination energies were characterized using a double‐cantilever beam (DCB) cohesion testing method. Successive DCB specimens were prepared from previously separated specimens by adhering new substrates onto each side of the already tested specimen to probe delamination energies deeper into the SC. These properties of the SC were measured before and after UV exposure, both with and without sunscreens applied, to determine the role of sunscreen in preserving the barrier function of SC.

   The drying stress in SC starts increasing sooner and rises to a higher plateau stress value after UVA exposure as compared to non‐UV‐exposed control specimens. For specimens that had sunscreen applied, the UVA‐exposed and non‐UV‐exposed SC had similar drying stress profiles. Additionally, specimens exposed to UVB without protection from sunscreen exhibited significantly lower delamination energies than non‐UV‐exposed controls. With commercial sunscreen applied, the delamination energy for UV‐exposed and non‐UV‐exposed tissue was consistent, even up to large doses of UVB.

   In vitrothin‐film mechanical analysis techniques can readily characterize the effects of SC's exposure to UV radiation. The methods used in this study demonstrated commercial sunscreens were able to preserve the biomechanical properties of SC during UV exposure, thus indicating the barrier function of SC was also maintained.

    

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2. Oral administration of lipoteichoic acid from Lactobacillus rhamnosus GG overcomes UVB‐induced immunosuppression and impairs skin tumor growth in mice

   https://doi.org/10.1002/eji.201848024  

   Friedrich, Adrián D. ; Campo, Valeria E. ; Cela, Eliana M. ; Morelli, Adrian E. ; Shufesky, William J. ; Tckacheva, Olga A. ; Leoni, Juliana ; Paz, Mariela L. ; Larregina, Adriana T. ; González Maglio, Daniel H. ( July 2019 , European Journal of Immunology)

   There is increasing evidence of the relevant connection and regulation between the gut and skin immune axis. In fact, oral administration of lipoteichoic acid (LTA) fromLactobacillus rhamnosusGG (LGG) prevents the development of UV‐induced skin tumors in chronically exposed mice. Here we aim to evaluate whether this LTA is able to revert UV‐induced immunosuppression as a mechanism involved in its anti‐tumor effect and whether it has an immunotherapeutic effect against cutaneous squamous cell carcinoma. Using a mouse model of contact hypersensitivity, we demonstrate that LTA overcomes UV‐induced skin immunosuppression. This effect was in part achieved by modulating the phenotype of lymph node resident dendritic cells (DC) and the homing of skin migratory DC. Importantly, oral LTA reduced significantly the growth of established skin tumors once UV radiation was discontinued, demonstrating that it has a therapeutic, besides the already demonstrated preventive antitumor effect. The data presented here strongly indicates that oral administration of LTA represents a promising immunotherapeutic approach for different conditions in which the skin immune system is compromised.

    

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3. Sex, synchrony, and skin contact: integrating multiple behaviors to assess pathogen transmission risk

   https://doi.org/10.1093/beheco/araa002  

   Leu, Stephan T ; Sah, Pratha ; Krzyszczyk, Ewa ; Jacoby, Ann-Marie ; Mann, Janet ; Bansal, Shweta ( February 2020 , Behavioral Ecology)

   Barrett, Louise (Ed.)

   Abstract Direct pathogen and parasite transmission is fundamentally driven by a population’s contact network structure and its demographic composition and is further modulated by pathogen life-history traits. Importantly, populations are most often concurrently exposed to a suite of pathogens, which is rarely investigated, because contact networks are typically inferred from spatial proximity only. Here, we use 5 years of detailed observations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) that distinguish between four different types of social contact. We investigate how demography (sex and age) affects these different social behaviors. Three of the four social behaviors can be used as a proxy for understanding key routes of direct pathogen transmission (sexual contact, skin contact, and aerosol contact of respiratory vapor above the water surface). We quantify the demography-dependent network connectedness, representing the risk of exposure associated with the three pathogen transmission routes, and quantify coexposure risks and relate them to individual sociability. Our results suggest demography-driven disease risk in bottlenose dolphins, with males at greater risk than females, and transmission route-dependent implications for different age classes. We hypothesize that male alliance formation and the divergent reproductive strategies in males and females drive the demography-dependent connectedness and, hence, exposure risk to pathogens. Our study provides evidence for the risk of coexposure to pathogens transmitted along different transmission routes and that they relate to individual sociability. Hence, our results highlight the importance of a multibehavioral approach for a more complete understanding of the overall pathogen transmission risk in animal populations, as well as the cumulative costs of sociality. 

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4. Evaluation of fireground exposures using urinary PAH metabolites

   https://doi.org/10.1038/s41370-021-00311-x  

   Hoppe-Jones, Christiane ; Griffin, Stephanie C. ; Gulotta, John J. ; Wallentine, Darin D. ; Moore, Paul K. ; Beitel, Shawn C. ; Flahr, Leanne M. ; Zhai, Jing ; Zhou, Jin J. ; Littau, Sally R. ; et al ( September 2021 , Journal of Exposure Science & Environmental Epidemiology)

   Abstract Background Firefighters have increased cancer incidence and mortality rates compared to the general population, and are exposed to multiple products of combustion including known and suspected carcinogens. Objective The study objective was to quantify fire response exposures by role and self-reported exposure risks. Methods Urinary hydroxylated metabolites of polycyclic aromatic hydrocarbons (PAH-OHs) were measured at baseline and 2–4 h after structural fires and post-fire surveys were collected. Results Baseline urine samples were collected from 242 firefighters. Of these, 141 responded to at least one of 15 structural fires and provided a post-fire urine. Compared with baseline measurements, the mean fold change of post-fire urinary PAH-OHs increased similarly across roles, including captains (2.05 (95% CI 1.59–2.65)), engineers (2.10 (95% CI 1.47–3.05)), firefighters (2.83 (95% CI 2.14–3.71)), and paramedics (1.84 (95% CI 1.33–2.60)). Interior responses, smoke odor on skin, and lack of recent laundering or changing of hoods were significantly associated with increased post-fire urinary PAH-OHs. Significance Ambient smoke from the fire represents an exposure hazard for all individuals on the fireground; engineers and paramedics in particular may not be aware of the extent of their exposure. Post-fire surveys identified specific risks associated with increased exposure. 

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5. Mechanisms underlying disruption of oocyte spindle stability by bisphenol compounds

   https://doi.org/10.1530/REP-19-0494  

   Yang, Luhan ; Baumann, Claudia ; De La Fuente, Rabindranth ; Viveiros, Maria M ( April 2020 , Reproduction)

   null (Ed.)

   Accurate chromosome segregation relies on correct chromosome-microtubule interactions within a stable bipolar spindle apparatus. Thus, exposure to spindle disrupting compounds can impair meiotic division and genomic stability in oocytes. The endocrine disrupting activity of bisphenols such as bisphenol A (BPA) is well recognized, yet their damaging effects on spindle microtubules (MTs) is poorly understood. Here, we tested the effect(s) of acute exposure to BPA and bisphenol F (BPF) on assembled spindle stability in ovulated oocytes. Brief (4 h) exposure to increasing concentrations (5, 25, and 50 µg/mL) of BPA or BPF disrupted spindle organization in a dose-dependent manner, resulting in significantly shorter spindles with highly unfocused poles and fragmented pericentrin. The chromosomes remained congressed in an abnormally elongated metaphase-like configuration, yet normal end-on chromosome-MT attachments were reduced in BPF-treated oocytes. Live-cell imaging revealed a rapid onset of bisphenol-mediated spindle MT disruption that was reversed upon compound removal. Moreover, MT stability and regrowth were impaired in BPA-exposed oocytes, with few cold-stable MTs and formation of multipolar spindles upon MT regrowth. MT-associated kinesin-14 motor protein (HSET/KIFC1) labeling along the spindle was also lower in BPA-treated oocytes. Conversely, cold stable MTs and HSET labeling persisted after BPF exposure. Notably, inhibition of Aurora Kinase A limited bisphenol-mediated spindle pole widening, revealing a potential interaction. These results demonstrate rapid MT disrupting activity by bisphenols, which is highly detrimental to meiotic spindle stability and organization. Moreover, we identify an important link between these defects and altered distribution of key spindle associated factors as well as Aurora Kinase A activity. 

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