Edwin K Joe | PubMed Health

PubMed2003

Selective cell targeting with light-absorbing microparticles and nanoparticles.

We describe a new method for selective cell targeting based on the use of light-absorbing microparticles and nanoparticles that are heated by short laser pulses to create highly localized cell damage. The method is closely related to chromophore-assisted laser inactivation and photodynamic therapy, but is driven solely by light absorption, without the need for photochemical intermediates (particularly singlet oxygen). The mechanism of light-particle interaction was investigated by nanosecond time-resolved microscopy and by thermal modeling. The extent of light-induced damage was investigated by cell lethality, by cell membrane permeability, and by protein inactivation. Strong particle size dependence was found for these interactions. A technique based on light to target endogenous particles is already being exploited to treat pigmented cells in dermatology and ophthalmology. With exogenous particles, phamacokinetics and biodistribution studies are needed before the method can be evaluated against photodynamic therapy for cancer treatment. However, particles are unique, unlike photosensitizers, in that they can remain stable and inert in cells for extended periods. Thus they may be particularly useful for prelabeling cells in engineered tissue before implantation. Subsequent irradiation with laser pulses will allow control of the implanted cells (inactivation or modulation) in a noninvasive manner.

Apoptosis↗

PubMed2003

Cushing syndrome secondary to topical glucocorticoids.

An 11-year-old boy with a history of psoriasis presented with Cushingoid stigmata, which included weight gain, central obesity, violaceous striae, and facial plethora. It was discovered that he had used potent topical glucocorticoids for two months prior to the onset of his weight gain. Laboratory studies were consistent with adrenal suppression that improved after discontinuation of the use of topical glucocorticoids.

Administration, Cutaneous↗

PubMed2003

Sweet syndrome.

Sweet syndrome is characterized by fever, leukocytosis, and tender, erythematous, well-demarcated papules and plaques, which show dense neutrophilic infiltrates and papillary dermal edema. It may occur in the absence of other diseases but is often associated with malignant conditions and may be induced by various medications. Treatment with systemic glucocorticoids generally is successful but may require prolonged courses to suppress recurrences.

Adult↗