A revision of the multiple-path particle dosimetry model focusing on tobacco product aerosol dynamics

To assess the health impact of inhaled aerosols, it is necessary to understand aerosol dynamics and the associated dosimetry in the human respiratory tract. Although several studies have measured or simulated the dosimetry of aerosol constituents, the respiratory tract focus areas have been limited. In particular, the aerosols generated from tobacco products are complex composites and simulating their dynamics in the respiratory tract is challenging. To assess the dosimetry of the aerosol constituents of tobacco products, we developed a revised version of the Multiple-Path Particle Dosimetry (MPPD) model, which employs (1) new geometry based on CT-scanned human respiratory tract data, (2) convective mixing in the oral cavity and deep lung, and (3) constituent partitioning between the tissue and air, and clearance. The sensitivity analysis was conducted using aerosols composed of four major constituents of electronic cigarette (EC) aerosols to investigate the parameters that have a significant impact on the results. In addition, the revised model was run with 4 and 10 constituents in ECs and conventional cigarettes (CCs), respectively. Sensitivity analysis revealed that the new modeling and the physicochemical properties of constituents had a considerable impact on the simulated aerosol concentration and dosimetry. The simulations could be carried out within 3 min even when 10 constituents of CC aerosols were analyzed simultaneously. The revised model based on MPPD is an efficient and easy-to-use tool for understanding the aerosol dynamics of CC and EC constituents and their effect on the human body.

Cost of illness study for adult atopic dermatitis in Japan: A cross-sectional Web-based survey

Atopic dermatitis is a pruritic, eczematous dermatitis, the symptoms of which chronically fluctuate with remissions and relapses. Although a high psychosomatic and economic burden caused by atopic dermatitis is expected, few studies have been conducted estimating the cost of illness, including the self-medication costs and productivity loss due to atopic dermatitis. The aim of this study was to conduct a cross-sectional, Web-based survey of the direct medical costs, self-medication costs and productivity loss for adult atopic dermatitis patients, and estimate the burden of Japanese adult atopic dermatitis patients by disease severity. In a physician survey, the medical resource consumption related to medical treatments was surveyed by disease severity. The direct medical costs were calculated by multiplying the medical resource consumption and medical fee corresponding to each treatment. Based on the results of a patient survey, the self-medication costs and productivity loss were estimated by sex and disease severity. Atopic dermatitis-related productivity loss was calculated based on absenteeism, presenteeism, overall work impairment for employed workers and activity impairment for housewives. The nationwide estimations were calculated based on the estimated number of atopic dermatitis patients, employed workers with atopic dermatitis, and housewives with atopic dermatitis in their 20s-50s in Japan. Based on the surveys, all costs per patient and the scores increased with disease severity. The cost of illness for adult atopic dermatitis patients in Japan was estimated to be approximately JPY 3 trillion/year. Considering the physical and mental burdens, the burden of illness for adult atopic dermatitis was demonstrated to be vast.

Decrosslinking enables visualization of RNA-guided endonuclease-in situ labeling signals for DNA sequences in plant tissues

Information about the positioning of individual loci in the nucleus and the status of epigenetic modifications at these loci in each cell contained in plant tissue increases our understanding of how cells in a tissue coordinate gene expression. To obtain such information, a less damaging method of visualizing DNA in tissue that can be used with immunohistochemistry is required. Recently, a less damaging DNA visualization method using the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/associated caspase 9) system, named RNA-guided endonuclease-in situ labeling (RGEN-ISL), was reported. This system made it possible to visualize a target DNA locus in a nucleus fixed on a glass slide with a set of simple operations, but it could not be applied to cells in plant tissues. In this work, we have developed a modified RGEN-ISL method with decrosslinking that made it possible to simultaneously detect the DNA loci and immunohistochemistry signals, including histone modification, in various types of plant tissues and species.