Douglas R. Hoffman

Immediate and extended effects of sodium lauryl sulphate exposure on stratum corneum natural moisturizing factor

Natural moisturizing factor (NMF) serves as the primary humectant of the stratum corneum (SC), principally comprised of hygroscopic amino acids and derivatives that absorb moisture. Barrier disruption has been shown to differentially affect the levels of specific NMF components, though the kinetics of NMF component restoration following disruption have not been examined. Here, we investigated the impact of barrier disruption caused by surfactant exposure on a subset of NMF components immediately following exposure and out to 10 days post‐exposure.

Carboxymethyl-β-cyclodextrin mitigates toxicity of cadmium, cobalt, and copper during naphthalene biodegradation

Hazardous waste sites are commonly contaminated with both organic and metal pollutants. Many metal pollutants have been shown to inhibit organic pollutant biodegradation. We investigated the ability of a modified, polydentate cyclodextrin (carboxymethyl-beta-cyclodextrin, CMCD) to reduce the toxicity of 33.4 microM cadmium, cobalt or copper during naphthalene degradation by a Burkholderia sp. in 120 h aerobic, batch studies. The highest investigated concentration of CMCD, 3340 microM, reduced cadmium, cobalt, and copper toxicity. With each metal, the length of the lag phase was reduced (by as much as 108 h with cobalt or copper), the cell yield was increased (by as much as a factor of 16 with cobalt), and the growth rate was increased (by as much as a factor of 31 with cobalt). The degrader was unable to use CMCD as the sole source of carbon and energy. Our data suggest that the ability of CMCD to complex metals plays an important role in its ability to mitigate metal toxicity and that CMCD has the potential to enhance biodegradation in organic and metal co-contaminated environments.

Immediate and extended effects of abrasion on stratum corneum natural moisturizing factor

Natural moisturizing factor (NMF), principally comprised of hygroscopic amino acids and derivatives that absorb moisture from the surrounding environment, serves as the primary humectant of the stratum corneum (SC). Acute barrier disruption has been shown to differentially affect the concentration of NMF in the SC. This study measured the recovery kinetics of NMF after mechanical damage of the SC, which is not well understood.

Transfer efficiency of Staphylococcus aureus between nitrile exam gloves and nonporous fomites

This report describes fomite transmission of Staphylococcus aureus amongst various surfaces. A contact transfer protocol was completed to evaluate the movement of S aureus between a person wearing nitrile gloves and either: handshaking with another person with gloved hands, touching a plastic cellular telephone back, or touching a stainless steel rod. The data in this preliminary study imply that the highest bacterial transfer is with metal surfaces followed by plastic. Interestingly, glove-to-glove transfer occurred but transfered less bacteria than a plastic or metal surface. The observations from this study point to the need to clearly define hygiene behaviors to reduce the potential of hand- and surface-mediated transmission.

Impact of Stratum Corneum Damage on Natural Moisturizing Factor (NMF) in the Skin

The stratum corneum (SC) is a complex structure that protects our bodies and makes it possible for mammalian life on this planet. The SC employs a combination of both physical and biochemical processes to limit the movement of water in and out of the body although clearly it is the latter that is of most importance. The SC can be disturbed by comparatively minor injury caused by mechanical, occlusive, enzymatic, and chemical damages. Lipids and a family of hygroscopic molecules known as natural moisturizing factor (NMF) are vital to the SC’s ability to regulate epidermal permeability. This chapter reviews what is known about the impact of barrier disruption on key skin components and provides new insights into NMF responses following damage induced by sodium lauryl sulfate (SLS).