Adapting epicutaneous patch testing protocols to assess immediate-type skin reactions.

Objective: During the development of cosmetic formulations, in vitro and in vivo methods are essential tools used to reliably assess the skin irritation potential of a product or ingredient. Epicutaneous patch testing (single and/or multiple application protocols) has long been used as an initial in vivo method to screen for possible skin irritation properties of a substance or formulation. To confirm the mildness and dermatological and/or consumer acceptance of a product, use tests are often subsequently conducted.

Oral intake of specific bioactive collagen peptides reduces skin wrinkles and increases dermal matrix synthesis.

Dietary consumption of food supplements has been found to modulate skin functions and can therefore be useful in the treatment of skin aging. However, there is only a limited number of clinical studies supporting these claims. In this double-blind, placebo-controlled study, the effectiveness of the specific bioactive collagen peptide (BCP) VERISOL® on eye wrinkle formation and stimulation of procollagen I, elastin and fibrillin biosynthesis in the skin was assessed.

Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study.

Various dietary supplements are claimed to have cutaneous anti-aging properties; however, there are a limited number of research studies supporting these claims. The objective of this research was to study the effectiveness of collagen hydrolysate (CH) composed of specific collagen peptides on skin biophysical parameters related to cutaneous aging. In this double-blind, placebo-controlled trial, 69 women aged 35-55 years were randomized to receive 2.

Internet-based lay person rating of facial photographs to assess effects of a cleansing product and a decent cosmetic foundation on the attractiveness of female faces.

It is well established that decorative cosmetics can enhance female facial attractiveness. In this study, we investigated the effects of a cleanser and a decent foundation on attractiveness of female faces. Comparative rating of a set of facial photographs by a group of lay persons revealed that the cleansing product was significantly reducing the attractiveness of the stimulus persons.

Interlaboratory studies with a proposed patch test design to evaluate the irritation potential of surfactants.

Background: Development of cosmetic products and household detergents necessitates comparative study designs to assess the skin tolerance of products. In initial tests, the epicutaneous patch test for irritation is widely used.

Objectives: This study was conducted to develop a protocol that would facilitate a comparison of results obtained when tests are conducted by different laboratories.

Multicentre comparison of skin hydration in terms of physical-, physiological- and product-dependent parameters by the capacitive method (Corneometer CM 825).

A multicentre study for measuring skin hydration with 349 volunteers was carried out in six different laboratories. The purpose of the study was to investigate physical-, physiological- and product-dependent parameters of three test emulsions (base, base + moisturizer and base + moisturizer + lipids) in a double-blind study. A comparison between analogous and digital sensor technology of the Corneometer CM825 was examined.

In vitro model for contact sensitization: II. Induction of IL-1beta mRNA in human blood-derived dendritic cells by contact sensitizers.

Epidermal mRNA for interleukin 1beta (IL-1beta) has been shown to be increased following exposure of mouse skin to sensitizing compounds. In addition, this early upregulation of IL-1beta was specific for contact sensitizers, while expression of IL-1beta was unaffected by irritants. Langerhans cells are the major source of IL-1beta within the epidermis in the induction phase of skin sensitization.

In vitro model for contact sensitization: I. Stimulatory capacities of human blood-derived dendritic cells and their phenotypical alterations in the presence of contact sensitizers.

Dendritic cells (DC) are highly specialized antigen-presenting cells (APC) located in many non-lymphoid tissues and a specialized form of DC-the Langerhans cell (LC)-is found in the skin. The functionality of LC as APC is crucial for the induction of an allergic contact dermatitis. For a long time LC research has been hampered by the limiting numbers of functionally active LC that could be isolated from human skin.

Induction of IL-15 messenger RNA and protein in human blood-derived dendritic cells: a role for IL-15 in attraction of T cells.

IL-15 is a pleiotropic cytokine with IL-2-like functions. As IL-15 was shown to be mitogenic for T cells, we wondered whether human blood-derived dendritic cells (DC), as the primary stimulators of T cell responses, are able to produce IL-15. To test our hypothesis, DC were grown under serum-free conditions from human peripheral blood using granulocyte-macrophage CSF and IL-4.

In vitro analysis of immunoprotective effects of topical sunscreens.

The aim of this study was to evaluate procedures for the assessment of the immunoprotective capacities of topical sunscreens, using cell cultures. The exposure of humans to solar or ultraviolet radiation has been shown to induce numerous changes at the level of the immunoresponsiveness of the skin, which could be described as immune suppression. In this study, a sunscreen containing the commercially available UVB filters octyl triazone, phenylbenzimidazole sulfonic acid and methylbenzylidene camphor, was tested because of its capacity to protect from the immunosuppressive effects of UVB radiation.

Immunocompetent cells for in vitro screening of skin irritation.

The present studies were aimed at evaluating procedures for assessing the immunmodulatory effects of chemicals and preparations on macrophage differentiation and lymphocyte proliferation in cell cultures. The effects of 10 drugs and anti-inflammatory agents were monitored by determining thymidine incorporation into phytohaemagglutinin (PHA)-stimulated T cells in the lymphocyte transformation test (LTT) and the expression of two surface antigens on macrophages in the macrophage differentiation assay (MDA). One antigen was found on macrophages in acute inflamed tissue.

T cell receptor alpha and beta gene expression in a murine antigen-specific T suppressor lymphocyte clone with cytolytic potential.

The composition of alpha and beta TCR genes was analyzed in a murine BSA-specific Ts cell clone with cytolytic potential. The isolated poly(A)+ mRNA from Ts cell clone BVI/5 was used to construct a cDNA library in the bacteriophage lambda gt11. Full-length cDNA clones specific for TCR alpha and TCR beta genes have been detected and isolated by hybridization with specific oligonucleotide probes.

Specific in vivo suppression of lymph node cell proliferation and humoral immune responses by cloned antigen-specific T suppressor cells.

Two BSA-specific Ts cell clones have been isolated from CBA/J mice tolerized by low doses of BSA. Together with one Ts cell clone isolated from an immune animal, they have recently been characterized with regard to phenotypes and in vitro functions. In the present report the in vivo effector functions of two of them (Ts cell clones BVI/5 and HF1.

An evaluation of the existence of soluble suppressor factors in cloned antigen-specific T suppressor lymphocytes.

The suppressive activity of two bovine serum albumin-specific class II-restricted T suppressor cell clones (BVI/5 and 83/2-D11) was compared to that of a feeder cell-independent, IL 2-dependent subline (HF1.IL-2) of an originally antigen-dependent class II-restricted Ts cell clone (HF1). No soluble suppressor factors can be found in BVI/5 and 83/2-D11 Ts cell extracts or culture supernatants under conditions where an unspecific factor can be derived from HF1.

Isolation of a bovine serum albumin-specific T-suppressor cell clone and evaluation of its in vitro functions.

This communication describes a newly isolated T-suppressor (Ts) cell clone, BVI/5, derived from a CBA/J mouse tolerized to low doses of bovine serum albumin (BSA). The cells are Thy-1.2+, Lyt-1.

Expression of L3T4 molecules on Lyt-2+, class II-restricted antigen-specific T suppressor lymphocytes.

Three bovine serum albumin-specific Lyt-2+ T suppressor (Ts) cell clones from CBA/J mice have been analyzed with regard to expression of L3T4 molecules. All three Ts-cell clones can be stained with monoclonal antibodies (mAb) to L3T4. Tested for the two clones restricted to recognition of Ek determinants, antigen-specific proliferation on antigen-presenting cells, but not the proliferation induced by conditioned medium can be inhibited by L3T4-specific mAb.