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Hydrophilic poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) shows biocompatibility because the pendant phosphorylcholine group has the same chemical structure as the hydrophilic part of phospholipids that form cell membranes. Hollow particles can be used in various fields, such as a carrier in drug delivery systems because they can encapsulate hydrophilic drugs. In this study, vinyl group-decorated silica particles with a radius of 150 nm were covered with cross-linked PMPC based on the graft-through method. The radius of PMPC-coated silica particles increased compared to that of the original silica particles. The PMPC-coated silica particles were immersed in a hydrogen fluoride aqueous solution to remove template silica particles to prepare the hollow particles. The PMPC hollow particles were characterized by dynamic light scattering, infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy observations. The thickness of the hollow particle shell can be controlled by the polymerization solvent quality. When a poor solvent for PMPC was used for the polymerization, PMPC hollow particles with thick shells can be obtained. The PMPC hollow particles can encapsulate hydrophilic guest molecules by immersing the hollow particles in a high-concentration guest molecule solution. The biocompatible PMPC hollow particles can be used in a drug carrier.

The presence of stimulating TSH receptor antibody (TRAb) results in Graves disease with thyrotoxicosis. However, some patients with Graves disease are euthyroid despite the presence of this antibody. Patient: A 42-year-old Japanese woman had suffered from diplopia. Thyroid function, however, was normal. Serum TRAb levels were elevated at 1.7 U/L (normal range: under 1.0 U/L). The working diagnosis was euthyroid Graves disease. Eighteen months later, she noticed pain and tumor in the anterior region of the neck. Physical examination revealed 3.2-cm diameter, firm tumor in the left lobe of thyroid accompanied by exquisite tenderness. The serum free plasma free thyroxin, free triiodethyronine, and TSH was 1.60 ng/dL, 3.62 pg/mL, and below 0.01 mU/L, respectively. The erythrocyte sedimentation rate was 64 mm/h, TRAb values had increased to 3.52 U/L. Three months later, the serum levels of FT4 and TRAb increased and the diagnosis of Graves disease with thyrotoxicosis was made. To our best knowledge, this is the first case report of euthyroid Graves disease being connected to hyperthyroid Graves disease by subacute thyroiditis.