Recent in In vivo (page 4 of 5)

Mechanisms of Tape Stripping and Protein Quantification

In this article, several methods to quantify the protein collected by tape stripping are described, including traditional gravimetric methods as well as novel colorimetric and visible spectroscopic techniques. Further, one colorimetric method is described to effectively determine the keratolytic efficacy of various materials in vivo, suggesting additional roles for this method.

In the Land of the Blind: Applying a Single-blind Study to Finished Products

Following positive feedback from a previous column on the placebo effect, Wiechers readdresses clinical study design in relation to cosmetic claim substantiation—this time discussing when to perform double-blind studies and when to perform single-blind studies.

In vivo Quantification of Corneocyte Lipids by Image Analysis

In a new method described here by the authors, fluorescence emitted from samples and captured by image analysis is used to quantify the number of lipids present in the cornified cell envelope. This in vivo approach is fast and noninvasive and could be used to screen molecules for potential moisturizing and restructuring effects.

The Air Up There: Skin VOCs

In 2001, Japanese researchers reported that after the age of 40, some individuals develop a malodor known as “aging odor,” attributed to the presence of unsaturated C9, 2-nonenal. George Preti, PhD, a member of Monell Chemical Senses Center and an adjunct professor of dermatology at the University of Pennsylvania School of Medicine, was interested by this report and began to conduct research of his own.

Dihydroavenanthramide D for Anti-irritant and Anti-itch

Naturally occurring and synthetic avenanthramides were evaluated for their efficacy to inhibit substance P-induced release of histamine from mast cells. In vivo tests showed that four synthetic avenanthramides demonstrated ability to significantly reduce histamine-induced itch and redness. Dihydroavenanthramide D was also shown to be an excellent antioxidant.

Enhancing, Measuring Skin Penetration

Skin penetration is of great interest to personal care formulators for many reasons. Following are a few recent findings.

Tech Edge--Optical Tools to Examine the Structure of Cosmetics Products

To monitor or anticipate what can happen in the creation of a cosmetic product when components are combined and as time passes is no trivial task especially when compounded with the psychophysical needs for the product to fit a specific concept and to spread, feel, pour and appear elegant.

New Directions for Sensitive Skin Research

This brief review provides an insight into the current standing of sensitive skin research, including recent findings on the possible role of nerve growth factor as an underlying mechanism and predictive tool for sensitive skin.

A Screening Technique for Antiperspirant Testing

A standardized in vivo test design for screening up to eight antiperspirant formulations in one panel is described. Dose-response curves for new raw materials or formulations can be performed in the same panel.

Subjective Skin Condition And Its Association With Objective Skin Measurements

From a group of 302 volunteers, the authors obtained both selfreported Subjective evaluations of skin condition and objective measurements of skin conditions, and then looked for correlations between the subjective and objective skin measures.

A Dermatologic View--Bioengineering Analysis of Water Hydration

The water content of the stratum corneum (SC) influences almost every biophysical property measurable at the skin surface. Water hydration can be measured using the plastic occlusion stress test (POST) or the water sorption-desorption test (WSDT).

Evaluating ACD Frequency After Reducing Exposure to Sensitizers

The economic burden of contact dermatitis is extensive due to work hours lost and physician visits. In the workplace, for example, contact dermatitis (irritant and allergic) accounts for 40% of all occupational illnesses (excluding injury) and 25% of time lost from work. Common sensitizers leading to allergic contact dermatitis (ACD) include metals, plants, cosmetics, rubber compounds and medicines.

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