Dendritic cells and their role in skin-induced immune responses

Role of solid lipid nanoparticles as photoprotective agents in cosmetics

BACKGROUND

Novel drug delivery systems have gained popularity since last two decades because of its advantages over conventional dosage forms. Effect of UV radiation on skin can cause either acute or chronic damage to our skin. Solid lipid nanoparticles (SLNs) were developed as novel carrier over the conventional carrier systems like liposomes and emulsions. The SLNs were selected as a carrier for the formulation because of its ability to protect the labile drug particles, the ability to make the drug release in a controlled manner, and occlusive property of the SLNs.

OBJECTIVE

The current review is an attempt to focus on the characteristics of solid lipid nanoparticles, methods for the preparations, and their cosmetic applications along with some future perspectives of the nanodrug delivery systems.

METHODS

A review of the current literature of solid lipid nanoparticles (SLNs) as novel carrier showed better photoprotection in sunscreens.

RESULTS AND CONCLUSIONS

The disadvantages of conventional sunscreens can be overcome by incorporation of solid lipid nanoparticles. On comparing the lipid nanobased systems with traditional cosmetic products, the occlusion can be achieved without the use of paraffin and other greasy oils. The film formed by lipid nanoparticles will be smooth as compared to the inflexible films formed by the paraffin. Newer approaches may lead to even better results. They also possess excellent UV-blocking activity and showed better photoprotection.

Immunohistochemical detection of Langerhans cells in dental granulomas and radicular cysts

OBJECTIVE

Dental granulomas (DGs) and radicular cysts (RCs) are chronic periapical lesions frequently involving the jaws. Langerhans cells (LCs) are dendritic cells responsible for the presentation of antigens to T lymphocytes. This study examined the expression of LCs in DG and RCs by immunohistochemical staining.

STUDY DESIGN

Eighteen cases of DGs and 26 cases of RCs were analyzed using anti-CD1a marker.

RESULTS

CD1a-labeled LCs were observed in 11.1% of DGs and in 69.2% of RCs, showing a significant correlation (P < 0.0001; Fisher's test). In DGs, LCs were only observed in granulation tissue, showing discrete immunostaining density. In RCs, LCs exhibited both a round and a dendritic shape in all epithelial layers. Although a correlation was observed between immunostaining density and epithelial thickness, as well as between immunostaining and inflammatory intensity, the differences were not significant in radicular cysts.

CONCLUSION

Langerhans cells provide important insight into the immunopathogenesis of chronic periapical lesions.

Langerhans cells in cutaneous tumours: immunohistochemistry study using a computer image analysis system

Immunohistochemistry, based on antibody anti-S100 protein, was used to evaluate the Langerhans cells (LC) in benign and malign skin neoplasias. These cells were quantitatively estimated using a computer image analysis (OPTIMAS software system, Version 6.1) in skin biopsies diagnosed as basal cell carcinoma (BCC), epidermoid carcinoma (EpC), trichoepithelioma (TE), keratoacanthoma (KA), seborreic keratosis (SK) and actinic keratosis (AK). The antibody anti-S100 protein recognized them. No significant variations were observed in the number of LC among malignant tumour (BCC = 23.25 +/- 5.81 and EpC = 20.88 +/- 4.24). Benign lesions (AK = 33.04 +/- 7.11; TE = 55.74 +/- 9.35; SK = 42.38 +/- 9.92, and KA = 47.62 +/- 10.4) presented a higher number of LC when they were compared among them and to malignant and normal tissues. No significant differences were observed in LC area and volume between benign and malign neoplasias. These results indicate possibly differences in the immunogenicity between benign and malign epidermic tumours. In conclusion, the experimental computer assessment method was reliable and consistent to morphometric analysis of tumoural tissues.

Glycobiology of Head and Neck Squamous Epithelia and Carcinomas

An impressive variety of regulatory processes including cell adhesion and migration, proliferation, apoptosis and differentiation folding and routing of glycoproteins have been found to be mediated by specific lectin-carbohydrate interactions. This article summarizes the data on glycobiological aspects of differentiation of squamous epithelia in the head and neck region under physiological conditions and in cancer. The possible function of lectins in tumor development and invasiveness is debated. Introduction of labeled endogenous lectins as a tool for the study of functional glycomics at the cellular level in head and neck squamous epithelia and carcinomas enables a complex interpretation of studied data because these lectins are normally occurring in these tissues. The lectinology of Langerhans cells in head and neck squamous epithelia and carcinoma is also mentioned. Finally, the use of the described data in the diagnosis and prospectively in the treatment of head and neck squamous cell carcinoma is shown.

Lymphocyte subsets, macrophages and Langerhans cells in actinomycetoma and eumycetoma tissue reaction

The aim of this work was to demonstrate, quantify and compare cell elements in the inflammatory infiltrate of 23 skin lesions of actinomycetoma (ACM) and 17 of eumycetoma (EUM). Epidermal Langerhans cells (LC) population was also analyzed in 18 ACM, 13 EUM and ten normal skin samples as control group. Tissue response in both groups of mycetoma showed CD4 and CD8 T lymphocytes surrounding the neutrophils aggregates with macrophages, revealed by CD68 antibody, among them. B lymphocytes were not identified. ACM lesions showed a higher number of CD8+ lymphocytes (P=0.02) and macrophages (P=0.01) when compared with EUM lesions. As well as morphologically altered, displaying irregular and short dendritic processes, LC were depleted both in ACM and EUM lesions (P=0.0004) when compared with normal skin but no difference between both types of mycetoma (P>0.05) was found. Results suggest that cellular mediated immunity may play a role in mycetoma pathogenesis. The morphological alterations and marked reduction of LC in mycetoma lesions might reflect a depressed cellular immune response, partially explaining the chronic course and unresponsiveness to treatment of this group of diseases.