Systemic and immunotoxicity of silver nanoparticles in an intravenous 28 days repeated dose toxicity study in rats.

Because of its antibacterial activity nanosilver is one of the most commonly used nanomaterials. It is increasingly used in a variety of both medical and consumer products resulting in an increase in human exposure. However, the knowledge on the systemic toxicity of nanosilver is relatively limited.

Effect of ammonia in cigarette tobacco on nicotine absorption in human smokers.

The function of ammonia as tobacco additive is subject of scientific debate. It is argued that ammonia, by increasing the proportion of free nicotine, increases the absorption of nicotine in smokers. As a result of the addition of ammonia to cigarettes, smokers get exposed to higher internal nicotine doses and become more addicted to the product.

Ultraviolet light and resistance to infectious diseases.

Exposure to ultraviolet (UV) radiation, as in sunlight, can modulate immune responses in animals and humans. This immunomodulation can lead to positive health effects especially with respect to certain autoimmune diseases and allergies. However, UV-induced immunomodulation has also been shown to be deleterious.

Suppression of different phases of systemic contact hypersensitivity by urocanic acid oxidation products.

On exposure to UV-B, the epidermal component trans-urocanic acid (UCA) is not only photoisomerized into cis-UCA but will also, at least in part, be photooxidized into UCA oxidation products (UOPs). We hypothesized that UOPs can mimic UV-induced systemic immunosuppression comparable to the suppressive properties already established for cis-UCA. A crude mixture of UOPs showed a significant suppression of the sensitization phase of the systemic contact hypersensitivity (CHS) response to picryl chloride (PCl).

Ultraviolet B radiation induces upregulation of calcitonin gene-related peptide levels in human Finn chamber skin samples.

One of the neuropeptides that plays a role in UVB-induced immunomodulation is calcitonin gene-related peptide (CGRP), as demonstrated in several animal studies. CGRP can be detected in human skin, but effects of UVB exposure on CGRP levels in human skin are not known. We determined CGRP levels in human Finn chamber skin samples of 15 UVB-irradiated and 10 control volunteers.