Dispersion of luminescent nanoparticles in different derivatives of poly(ethyl methacrylate).

Gd2O3:Tb(5%) nanoparticles were prepared via the polyol route and dispersed without any stabilizer in several ethyl methacrylate derivatives matrices such as poly(ethyl methacrylate), poly(2-methoxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate) (PHEMA). Nanocomposites were obtained via free-radical polymerization of methacrylic monomers with ethylene glycol dimethacrylate as crosslinker and colloidal solution of Gd2O3:Tb(5%) nanoparticles. Best results are obtained with PHEMA in which the dispersed Gd2O3:Tb(5%) nanoparticles are spherical with a mean diameter of 15 nm, as measured by TEM. The obtained solid Gd2O3:Tb(5%)/PHEMA nanocomposites are highly transparent (in the visible spectral range) and exhibit characteristic photoluminescence of Tb3+ 5D4-7F(J) (J = 6-3), with 5D4-7F5 strong green emission at 536 nm upon UV excitation. The nanoparticles and nanocomposites have been well characterized by high-resolution transmission electron microscope (TEM), UV/Vis transmission spectra, photoluminescence excitation, and emission spectra.

[Sequential histological and immunohistochemical assessment of proliferation and apoptotic markers during treatment of psoriasis with antitumor necrosis factor alpha (infliximab)]. / Evaluación histológica e inmunohistoquímica secuencial de marcadores de proliferación y apoptosis durante el tratamiento de la psoriasis con anti-factor de necrosis tumoral alpha (infliximab).

BACKGROUND AND OBJECTIVES: Psoriasis is an inflammatory skin disease of immunologic nature that is mediated by T-helper-1 cytokines. Clinical response to treatment with antitumor necrosis factor (TNF) alpha antibodies (infliximab) has been significant; however, the mechanisms for clearance of lesions have not been elucidated. The aim of the present study was to assess variations in the histology and expression of proliferation and apoptotic markers in sequential skin biopsies of patients with psoriasis treated with infliximab. MATERIAL AND METHODS: We studied skin biopsies (of lesioned and healthy skin) from 3 patients with extensive moderate-to-severe psoriasis (mean psoriasis area and severity index [PASI] score, 35) treated with intravenous infliximab infusions (5 mg/kg) at weeks 0, 2, and 6. Biopsies were taken on days 0, 14, and 28, and were processed for conventional histological and immunohistochemical study. The apoptotic markers used were TP53, B-cell lymphoma 2 protein, anticaspase 3, and anticaspase 8. The cell proliferation marker used was Ki67. RESULTS: Treatment with infliximab was associated with a significant clinical improvement in 3 patients (mean PASI score, 21.6 at 14 days and 13.9 at 6 weeks), which correlated with the progressive disappearance of histological lesions with a decrease in epidermal proliferation. However, apoptosis was not observed, and the samples tested negative for anticaspase antibodies. Expression of TP53 decreased 2 weeks after starting treatment, and was similar to that in normal skin at 28 days. CONCLUSIONS: Clinical and histological response of psoriasis to infliximab was not associated with a significant increase in the apoptotic markers assessed.