Silicon phthalocyanine (Pc 4) photodynamic therapy is a safe modality for cutaneous neoplasms: results of a phase 1 clinical trial.

Background: Photodynamic therapy (PDT) is a non-invasive treatment for non-melanoma skin cancer. However, PDT systems currently used clinically have limitations such as pain and superficial tissue penetration. The silicon phthalocyanine Pc 4 is a second-generation photosensitizer with peak absorption in the far red at 675 nm.

Smoking and skin aging in identical twins.

Background: A twin pair can provide a rare opportunity to control for genetic susceptibility and exposure variables, which often serve as major confounders in population-based studies on the relationship between smoking and skin aging.

Observations: We describe a unique twin pair who spent not only their first 2 decades of life together but also in their later decades had the same type of job at the same latitude, resulting in well-matched levels of significant sun exposure. However, the twins differed markedly in regard to smoking history; the twin with an approximately 52.

Effect of topical vitamin D analogue on in vivo contact sensitization.

Background: The immunomodulatory role of vitamin D and its analogues has been demonstrated in vitro and in vivo using animal models. We evaluated the effect of a vitamin D analogue, calcipotriene, in vivo on human subjects using a contact hypersensitivity model.

Observations: Subjects were pretreated with topical calcipotriene, simulated solar radiation, or both on buttock skin.

Protective effects of tea polyphenols and caffeine.

Compounds derived from botanical sources, such as polyphenols from tea, have been of interest as possible therapeutic agents. Their benefits in terms of cancer chemoprevention have also been investigated primarily through in vitro and animal in vivo studies. Ultraviolet light from solar radiation has been proven to initiate and promote skin cancer, which is the most common malignancy in light-skinned populations.

Ultraviolet immunosuppression: mechanisms and consequences.

It is well recognized that exposure to solar radiation has several detrimental consequences, both acute and chronic. The suppression of immune functions remains one of the most intriguing phenomena brought about by ultraviolet (UV) radiation. This concept has challenged experts from various disciplines including dermatology, immunology, and photobiology.