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.

The combination of biomarkers examined appears to be a good overall descriptor of the health of the scalp in dandruff, and changes in these biomarkers track with tissue-level events that underlie clinical efficacy in the treatment of dandruff by ZPT shampoo. For the first time, we demonstrate a set of tools that extend beyond flaking scores to provide insight into specific biological changes occurring on the scalp to enable an objective assessment of scalp health.

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.

The oxidative stress element of unhealthy scalp leads to compromised pre-emergent hair formation and poorly formed hair as it grows. Only cosmetic solutions can minimize the impact of unhealthy hair and to achieve healthy looking and feeling hair, the scalp health must be normalized first. The objectives of this research were to both investigate whether oxidative stress was a relevant aetiological element in scalp dandruff and seborrhoeic dermatitis and whether scalp condition affects the quality of hair that grows from it. Further, this research was designed to determine whether an effective antidandruff shampoo would repair and protect the scalp and pre-emergent hair from oxidative stress. This study demonstrated that oxidative stress is an aetiological element relevant to the dandruff condition and that a potentiated ZPT shampoo effectively improves scalp condition, including a reduction in oxidative stress. The compromised hair condition associated with dandruff is concomitantly improved when the scalp condition is improved. It appears that there is a direct link between hair quality and scalp health.R esum e La composante de stress oxydatif du cuir chevelu en mauvaise sant e compromet la qualit e du cheveu en formation et celle du cheveu en croissance. Seules des solutions cosm etiques peuvent le minimiser et pour obtenir un cheveu a l'apparence et au toucher sains, le cuir chevelu doitêtre d'abord normalis e. L'objectif de cette recherche etait a la fois de d eterminer si le stress oxydatif est un el ement etiologique pertinent dans le cuir chevelu a pellicules et la dermatite s eborrh eique et si l' etat du cuir chevelu affecte la qualit e des cheveux qui y poussent. De plus, cette recherche a et e conc ßue pour d eterminer si un shampoing anti-pelliculaire efficace serait capable de r eparer et de prot eger le cuir chevelu et les cheveux avant leur croissance du stress oxydatif. Cette etude a d emontr e que le stress oxydatif est un el ement etiologique pertinent a l' etat pelliculaire et un shampooing au pyrithione de zinc am eliore efficacement l' etat du cuir chevelu, et permet une r eduction du stress oxydatif. L' etat de la chevelure abîm ee par les pellicules est am elior e de fac ßon concomitante a l'am elioration de l' etat du cuir chevelu. Il s'av ere qu'il y a un lien direct entre la qualit e des cheveux et la sant e du cuir chevelu.