Comparison of histological measures of skin photoaging.

Background: Dermal elastosis is considered the histological 'gold standard' for evaluation of skin photoaging, but the relation of the level of dermal elastosis to other histological indicators of photoaging is not clear.

Objective: To investigate how various proposed histological measures of photoaging compare with the level of dermal elastosis.

Methods: Prospective, community-based study in Southeast Queensland, Australia, among 89 participants aged 40-82 years.

A broad-spectrum sunscreen prevents cumulative damage from repeated exposure to sub-erythemal solar ultraviolet radiation representative of temperate latitudes.

Background: We have previously shown the detrimental effects of 19 sub-erythemal exposures to daily ultraviolet radiation (DUVR, which mimics non-extreme exposure conditions), delivered over 4 weeks to volunteers. This source had UVA (320-400 nm) to UVB (290-320 nm) irradiance ratio of 25, instead of that close to 10 that is typically the case with solar-simulated radiation (SSR) that represents summer global sunlight with a clear sky and quasi-zenith solar irradiance.

Objective: Here, we report on an extension of this previous study, in which we evaluated the photoprotection afforded by a broad-spectrum daily-care product with a low-sun protection factor (SPF 8, UVA-PF 7 and 3* rated UVA protection).

Biological effects of simulated ultraviolet daylight: a new approach to investigate daily photoprotection.

Background: The irradiance of standard ultraviolet daylight (UV-DL) is representative of most frequently encountered UV exposure conditions and simulators of UV-DL can now be used to properly investigate the biological effects of a non-extreme UV radiation. One of the characteristics of the simulated UV-DL used in this study is its dUVA to dUVB irradiance ratio, which amounts to 24, instead of close to 10, for the simulated zenithal UV radiation (UV-SSR).

Purpose/methods: The aim of our study was to compare photobiological effects induced, in human skin, by acute and semi-chronic exposure to simulated UV-DL with those induced by UV-SSR.

Histological evaluation of a topically applied retinol-vitamin C combination.

Two double-blind studies versus vehicle were carried out to investigate the effects of a topically applied retinol plus vitamin C combination on epidermal and dermal compartments of aged or photoaged human skin. The two studies were performed on postmenopausal women who were selected for treatment based on the mild level of elastosis of their facial skin. At completion of treatment, skin biopsies were collected and processed for classical histology and immunohistochemistry.

Expression of tie receptor tyrosine kinase in human leukemia cell lines.

The tie gene encodes a receptor tyrosine kinase that together with its thus far unidentified ligand appears to play a distinct role in the regulatory pathway of early hematopoiesis and angiogenesis. Here, we attempted to define the possible involvement of tie in the pathobiology of hematopoietic malignancies by examining tie mRNA expression in human leukemia and lymphoma cells. We used a large panel of 93 well-characterized human continuous leukemia-lymphoma cell lines as model systems for the various hematopoietic cell lineages.