ORCID Profile
0000-0003-0633-8443
Current Organisation
University of Georgia
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Publisher: MDPI AG
Date: 08-09-2021
DOI: 10.3390/IJMS22189730
Abstract: Zinc pyrithione (ZnPT) is an anti-fungal drug delivered as a microparticle to skin epithelia. It is one of the most widely used ingredients worldwide in medicated sh oo for treating dandruff and seborrheic dermatitis (SD), a disorder with symptoms that include skin flaking, erythema and pruritus. SD is a multi-factorial disease driven by microbiol dysbiosis, primarily involving Malassezia yeast. Anti-fungal activity of ZnPT depends on the cutaneous availability of bioactive monomeric molecular species, occurring upon particle dissolution. The success of ZnPT as a topical therapeutic is underscored by the way it balances treatment efficacy with formulation safety. This review demonstrates how ZnPT achieves this balance, by integrating the current understanding of SD pathogenesis with an up-to-date analysis of ZnPT pharmacology, therapeutics and toxicology. ZnPT has anti-fungal activity with an average in vitro minimum inhibitory concentration of 10–15 ppm against the most abundant scalp skin Malassezia species (Malassezia globosa and Malassezia restrica). Efficacy is dependent on the targeted delivery of ZnPT to the skin sites where these yeasts reside, including the scalp surface and hair follicle infundibulum. Imaging and quantitative analysis tools have been fundamental for critically evaluating the therapeutic performance and safety of topical ZnPT formulations. Toxicologic investigations have focused on understanding the risk of local and systemic adverse effects following exposure from percutaneous penetration. Future research is expected to yield further advances in ZnPT formulations for SD and also include re-purposing towards a range of other dermatologic applications, which is likely to have significant clinical impact.
Publisher: Wiley
Date: 25-08-2021
DOI: 10.1002/ECY.3504
Abstract: Spatial rarity is often used to predict extinction risk, but rarity can also occur temporally. Perhaps more relevant in the context of global change is whether a species is core to a community (persistent) or transient (intermittently present), with transient species often susceptible to human activities that reduce niche space. Using 5-12 yr of data on 1,447 plant species from 49 grasslands on five continents, we show that local abundance and species persistence under ambient conditions are both effective predictors of local extinction risk following experimental exclusion of grazers or addition of nutrients persistence was a more powerful predictor than local abundance. While perturbations increased the risk of exclusion for low persistence and abundance species, transient but abundant species were also highly likely to be excluded from a perturbed plot relative to ambient conditions. Moreover, low persistence and low abundance species that were not excluded from perturbed plots tended to have a modest increase in abundance following perturbance. Last, even core species with high abundances had large decreases in persistence and increased losses in perturbed plots, threatening the long-term stability of these grasslands. Our results demonstrate that expanding the concept of rarity to include temporal dynamics, in addition to local abundance, more effectively predicts extinction risk in response to environmental change than either rarity axis predicts alone.
Publisher: Elsevier BV
Date: 04-2029
DOI: 10.1016/J.ADDR.2021.113929
Abstract: Topical products, widely used to manage skin conditions, have evolved from simple potions to sophisticated delivery systems. Their development has been facilitated by advances in percutaneous absorption and product design based on an increasingly mechanistic understanding of drug-product-skin interactions, associated experiments, and a quality-by-design framework. Topical drug delivery involves drug transport from a product on the skin to a local target site and then clearance by diffusion, metabolism, and the dermal circulation to the rest of the body and deeper tissues. Insights have been provided by Quantitative Structure Permeability Relationships (QSPR), molecular dynamics simulations, and dermal Physiologically Based PharmacoKinetics (PBPK). Currently, generic product equivalents of reference-listed products dominate the topical delivery market. There is an increasing regulatory interest in understanding topical product delivery behavior under 'in use' conditions and predicting in vivo response for population variations in skin barrier function and response using in silico and in vitro findings.
Publisher: Oxford University Press (OUP)
Date: 08-02-2023
DOI: 10.1093/CED/LLAD052
Abstract: Dermatological diseases are widespread and have a significant impact on the quality of life of patients however, access to appropriate care is often limited. Improved early training during medical school represents a potential upstream solution. This scoping review explores dermatology education during medical school, with a focus on identifying the factors associated with optimizing the preparation of future physicians to provide care for patients with skin disease. A literature search was conducted using online databases (Embase, MEDLINE, CINAHL and Scopus) to identify relevant studies. The Joanna Briggs Institute methodological framework for scoping reviews was used, including quantitative and qualitative data analysis following a grounded theory approach. From 1490 articles identified, 376 articles were included. Most studies were from the USA (46.3%), UK (16.2%), Germany (6.4%) and Canada (5.6%). Only 46.8% were published as original articles, with a relatively large proportion either as letters (29.2%) or abstracts (12.2%). Literature was grouped into three themes: teaching content, delivery and assessment. Core learning objectives were country dependent however, a common thread was the importance of skin cancer teaching and recognition that ersity and cultural competence need greater fostering. Various methods of delivery and assessment were identified, including computer-aided and online, audiovisual, clinical immersion, didactic, simulation and peer-led approaches. The advantages and disadvantages of each need to be weighed when deciding which is most appropriate for a given learning outcome. The broader teaching–learning ecosystem is influenced by (i) community health needs and medical school resources, and (ii) the student and their ability to learn and perform. Efforts to optimize dermatology education may use this review to further investigate and adapt teaching according to local needs and context.
Publisher: MDPI AG
Date: 17-05-2022
DOI: 10.3390/PHARMACEUTICS14051076
Abstract: Zinc pyrithione (ZnPT) is a widely used antifungal, usually applied as a microparticle suspension to facilitate delivery into the hair follicles, where it then dissociates into a soluble monomeric form that is bioactive against yeast and other microorganisms. In this study, we use multiphoton microscopy (MPM) and fluorescence lifetime imaging microscopy (FLIM) to characterise ZnPT formulations and map the delivery of particles into follicles within human skin. To simulate real-world conditions, it was applied using a massage or no-massage technique, while simultaneously assessing the dissolution using Zinpyr-1, a zinc labile fluorescent probe. ZnPT particles can be detected in a range of sh oo formulations using both MPM and FLIM, though FLIM is optimal for detection as it allows spectral and lifetime discrimination leading to increased selectivity and sensitivity. In aqueous suspensions, the ZnPT 7.2 µm particles could be detected up to 500 µm in the follicle. The ZnPT particles in formulations were finer (1.0–3.3 µm), resulting in rapid dissolution on the skin surface and within follicles, evidenced by a reduced particle signal at 24 h but enhanced Zinpyr-1 intensity in the follicular and surface epithelium. This study shows how MPM-FLIM multimodal imaging can be used as a useful tool to assess ZnPT delivery to skin and its subsequent dissolution.
Publisher: Wiley
Date: 22-04-2019
DOI: 10.1111/PHP.13100
Abstract: Zinc pyrithione is ubiquitous in commercial products particularly antidandruff sh oos. For the efficacy of zinc pyrithione therapeutic cleansers to be assessed accurately, the distribution of particles on the scalp needs to be visualized. Currently, no technique is available which provides the chemical specificity and sensitivity required. Here, we report application of fluorescence-lifetime imaging microscopy (FLIM) for high-contrast mapping of zinc pyrithione distribution on the scalp. Characterization of the zinc pyrithione emission by using both one-photon excitation at five specific wavelengths and two-photon excitation in the range of 740-820 nm revealed its FLIM fingerprint-a characteristic short average time-weighted emission lifetime of Τ
Publisher: Wiley
Date: 31-10-2021
Abstract: Plant damage by invertebrate herbivores and pathogens influences the dynamics of grassland ecosystems, but anthropogenic changes in nitrogen and phosphorus availability can modify these relationships. Using a globally distributed experiment, we describe leaf damage on 153 plant taxa from 27 grasslands worldwide, under ambient conditions and with experimentally elevated nitrogen and phosphorus. Invertebrate damage significantly increased with nitrogen addition, especially in grasses and non‐leguminous forbs. Pathogen damage increased with nitrogen in grasses and legumes but not forbs. Effects of phosphorus were generally weaker. Damage was higher in grasslands with more precipitation, but climatic conditions did not change effects of nutrients on leaf damage. On average, invertebrate damage was relatively higher on legumes and pathogen damage was relatively higher on grasses. Community‐weighted mean damage reflected these functional group patterns, with no effects of N on community‐weighted pathogen damage (due to opposing responses of grasses and forbs) but stronger effects of N on community‐weighted invertebrate damage (due to consistent responses of grasses and forbs). Synthesis . As human‐induced inputs of nitrogen and phosphorus continue to increase, understanding their impacts on invertebrate and pathogen damage becomes increasingly important. Our results demonstrate that eutrophication frequently increases plant damage and that damage increases with precipitation across a wide array of grasslands. Invertebrate and pathogen damage in grasslands is likely to increase in the future, with potential consequences for plant, invertebrate and pathogen communities, as well as the transfer of energy and nutrients across trophic levels.
Location: United States of America
No related grants have been discovered for Alexander Strauss.