Structure-dependent behaviours of skin layers studied by atomic force microscopy.

The multilayer skin provides the physical resistance and strength against the environmental attacks, and consequently plays a significant role in maintaining the mammalian health. Currently, optical microscopy (OM) is the most common method for the research related to skin tissues while with the drawbacks including the possibility of changing the native morphology of the sample with the addition of the chemical or immunological staining and the restricted resolution of images for the direct observation of the tissue structures. To investigate if the function of each tissue is structure-dependent and the how the injured skin returns to the intact condition, we applied atomic force microscopy (AFM) on the sectioned mice-skin to reveal the tissue structures with a nanoscale resolution. From the outermost stratum to the inner layer of the skin tissue, the respectively laminated, fibrous, and brick-like structures were observed and corresponded to various functions. Due to the mechanical differences between the tissue constituents and their boundaries, the sizes and arrangements of the components were characterised and quantified by the mechanical mapping of AFM, which enabled the analytical comparisons between tissue layers. For the wound model, the skin tissues were examined with the initial formation of blood vessels and type-I collagen, which agreed with the stage of healing process estimated by OM but showed more detail information about the evolution of proteins among the skin. In conclusion, the characterisation of the components that consist of skin tissue by AFM enables the connection of the tissue function to the corresponded ultrastructure.

Latent tuberculosis infection treatment for prison inmates: a randomised controlled trial.

SETTING: A prison in northern Taiwan. OBJECTIVE: To compare safety and the completion rate of the 4-month daily rifampicin regimen (4R) vs. the standard 6-month daily isoniazid regimen (6H) for latent tuberculosis infection (LTBI) in prison inmates. DESIGN: This was an open-label randomised trial among human immunodeficiency virus negative male inmates. Inmates without active tuberculosis (TB) who tested positive for both the tuberculin skin test and QuantiFERON®-TB Gold In-Tube were eligible, but those with baseline glutamic pyruvic transaminase (GPT) levels ≥ 120 U/l, bilirubin levels ≥ 2.4 U/l or a platelet count < 150 k/mm(3) were excluded. The primary endpoint was any adverse event that resulted in discontinuation of LTBI treatment. RESULTS: Participants (n = 373; 14% hepatitis B surface antigen positive, 21% anti-hepatitis C virus [HCV] positive) were randomised (stratified by hepatitis B virus, HCV status and 2-year prison term) to receive either 4R or 6H under directly observed treatment. The 4R group (n = 190) was less likely to experience an adverse event leading to discontinuation of treatment (2% vs. 12%, P < 0.001 for all adverse events; 0% vs. 8%, P < 0.001 for hepatotoxicity), and more likely to complete LTBI treatment (86% vs. 78%, P = 0.041), compared with the 6H group (n = 183). CONCLUSIONS: 4R is safer and has a higher completion rate than 6H as treatment for LTBI among male prison inmates.