Characteristics of 5015 Salivary Gland Neoplasms Registered in the Hiroshima Tumor Tissue Registry over a Period of 39 Years

Salivary gland neoplasms are uncommon, and their epidemiology in Japan has not been well described. We conducted a retrospective review of salivary gland tumors registered in the Hiroshima Tumor Tissue Registry over a period of 39 years. The subjects were 5015 cases ranging in age from 6 to 97 (mean, 54.3) years old. The incidence of both benign tumors and malignant tumors increased with age until 60−69 years and then declined. Among the 5015 salivary gland neoplasms, 3998 (80%) were benign and 1017 (20%) were malignant. Pleomorphic adenoma (PA) was the most frequent benign tumor (68%), followed by Warthin tumor (26%). Adenoid cystic carcinoma (ACC) (27%) and mucoepidermoid carcinoma (MEC) (26%) were the two most frequent malignant tumors. Characteristically, there was a very low incidence of polymorphous adenocarcinoma in Japan. The average annual age-adjusted incidence rate per 100,000 population was 3.3 for benign tumors and 0.8 for malignant tumors. This is the large-scale multi-institutional analysis to describe the characteristics of salivary gland neoplasms, based on the pathological tissue registry data. We hope that the present data can contribute to early diagnosis and effective treatment of salivary gland tumors and to cancer prevention

Stepwise Drug-Release Behavior of Onion-Like Vesicles Generated from Emulsification-Induced Assembly of Semicrystalline Polymer Amphiphiles

Tailoring unique nanostructures of biocompatible and degradable polymers and the consequent elucidation of shape effects in drug delivery open tremendous opportunities not only to broaden their biomedical applications but also to identify new directions for the design of nanomedicine. Cellular organelles provide the basic structural and functional motif for the development of novel artificial nanoplatforms. Herein, aqueous onion-like vesicles structurally mimicking multicompartmentalized cellular organelles by exhibiting exquisite control over the molecular assembly of poly(ethylene oxide)-block-poly(epsilon-caprolactone) (PEO-b-PCL) semicrystalline amphiphiles are reported. Compared to in situ self-assembly, emulsification-induced assembly endows the resulting nanoaggregates of PEO-b-PCL with structural diversity such as helical ribbons and onion-like vesicles through the molecular packing modification in the hydrophobic core with a reduction of inherent crystalline character of PCL. In particular, onion-like vesicles composed of alternating walls and water channels are interpreted by nanometer-scale 3D visualization via cryogenic-electron tomography (cryo-ET). Interestingly, the nature of the multi-walled vesicles results in high drug-loading capacity and stepwise drug release through hydrolytic cleavage of the PCL block. The crystalline arrangement of PCL at the molecular scale and the spatial organization of assembled structure at the nanoscale significantly affect the drug-release behavior of PEO-b-PCL nanovehiclesclose0