A comprehensive pathophysiology of dandruff and seborrheic dermatitis - towards a more precise definition of scalp health.

Despite an increasing knowledge of dandruff and seborrheic dermatitis (D/SD), the pathophysiological understanding is still incomplete but suggests a role of Malassezia yeasts in triggering inflammatory and hyper-proliferative epidermal responses. The objective of this report is to review published literature from in vivo studies of D/SD populations to provide a more complete description of overall scalp health. New biomolecular capabilities establish a depth of pathophysiological understanding not previously achievable with traditional means of investigation. Biomarkers representing inflammation, hyper-proliferation and barrier function are all perturbed by the D/SD condition and robustly respond to therapeutic resolution. These biomarkers can be sampled noninvasively, enabling their use in routine clinical evaluations as either surrogate endpoints or complementary ones to classical signs/symptoms to broaden the etiological learning.

Incubatory environment of the scalp impacts pre-emergent hair to affect post-emergent hair cuticle integrity.

OBJECTIVES: To determine whether the oxidative stress transmitted to newly grown hair from an unhealthy scalp has physical consequences to the cuticular condition and function. METHODS: A uniquely designed 24-week clinical study included 8 weeks of pretreatment with a cosmetic shampoo and 16 weeks of treatment with either a potentiated zinc pyrithione (ZPT) antidandruff shampoo or a placebo cosmetic shampoo. This clinical design allowed the growth and acquisition of hair samples under conditions of varying but known scalp health as a result of treating a dandruff/seborrheic dermatitis (D/SD) population. Two complementary methods were used to characterize the integrity of the cuticular surface. Hair surface hydrophobicity was assessed by quantifying water wetting force using a Wilhelmy balance method. Surface structure and porosity were assessed using dynamic vapor sorption (DVS) to gravimetrically quantify water sorption. RESULTS: Chemical oxidative stress to pre-emergent hair has been shown to have negative consequences to hair surface structure. Compared to a placebo shampoo control, use of a potentiated ZPT shampoo improved scalp health and significantly improved the following attributes associated with healthy hair: hair surface hydrophobicity (surface energy) and cuticular moisture barrier effectiveness (dynamic vapor sorption). CONCLUSIONS: Pre-emergent hair can be negatively impacted by the oxidative stress that occurs with an unhealthy scalp, possibly due to metabolic activity of resident microbes. Manifestations of the oxidative stress include altered cuticle surface properties that are responsible for its protective function; these effects are similar in type to those observed by bleaching post-emergent hair. These alterations have the potential to make the hair, once emerged from the scalp, more susceptible to the cumulative physical and chemical insults responsible for hair feel and look, fiber integrity, and overall retention.

Anaerobic biodegradation of aliphatic polyesters: poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) and poly(epsilon-caprolactone).

Poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), PHBO, represents a class of PHA copolymers that contain both short-chain-length and medium-chain-length repeat units. Radiolabeled and cold PHBO, containing 90 mol % 3-hydroxybutyrate and 10 mol % 3-hydroxyoctanoate were chemically synthesized using a new difunctional alkoxyzinc initiator. (14)C-PHBO was incubated with samples of anaerobic digester sludge, septage, freshwater sediment, and marine sediment under conditions resembling those in situ. In addition, it was incubated in laboratory-scale landfill reactors. (14)C-PCL (poly-epsilon-caprolactone) was incubated with anaerobic digester sludge and in landfill reactors. Biodegradation was determined by measuring generation of (14)CO(2) and (14)CH(4) resulting from mineralization of the radiolabeled polymers. PHBO was extensively mineralized in digester sludge, septage sediments, and the landfill reactors, with half-lives less than 30 days. PCL was not significantly mineralized in digester sludge over 122 days. In the landfill reactors, PCL mineralization was slow and was preceded by a long lag period (>200 days), suggesting that PCL mineralization is limited by its rate of hydrolysis. The results indicate that PHBO is practically biodegradable in the major anaerobic habitats that it may enter. In contrast, anaerobic biodegradation of PCL is less ubiquitous and much slower.

Detection of Staphylococcus aureus biofilm on tampons and menses components.

Culturing has detected vaginal Staphylococcus aureus in 10%-20% of women. Because growth mode can affect virulence expression, this study examined S. aureus-biofilm occurrence in 44 paired-tampon and vaginal-wash-specimens from 18 prescreened women, using fluorescent in situ hybridization (FISH). All 44 specimens were also analyzed for S. aureus by standard culturing on mannitol salt agar, which produced positive results for 15 of the 44 specimens. FISH detected S. aureus cells in all 44 specimens, and S. aureus biofilm was observed in 37 of the 44 specimens. Independent confirmation of the presence of S. aureus in specimens from all 18 women was also obtained by amplification, via polymerase chain reaction, of an S. aureus-specific nuclease gene. The results of this study demonstrate that S. aureus biofilm can form on tampons and menses components in vivo. Additionally, the prevalence of vaginal S. aureus carriage may be more prevalent than what is currently demonstrated by standard culturing techniques.