[Human Resource Development for Thyroid Ultrasound Examination Program in Fukushima].

As a response to the health effects associated with the Fukushima Daiichi Nuclear Power Plant accident that occurred after the Great East Japan Earthquake, the Thyroid Ultrasound Examination program as a part of the Fukushima Health Management Survey was started on Oct. 9th, 2011. Since this project required a large-scale cohort comprising all residents aged ≤ 18 years living in Fukushima when the earthquake happened, the nurturing of many ultrasound examiners was a matter of great urgency. Moreover, the standardization of examination procedures and skills of examiners were also important issues. Therefore, educational projects were established to develop ultrasound skills for medical doctors and technicians in Fukushima Prefecture. Marked efforts for this project resulted in increases in ultrasound examiners and institutions taking part in the Thyroid Ultrasound Examination project. Medical technicians specialized in ultrasound examinations are actively involved in these educational projects. We report the details of human resource development projects from the point of view of such medical technicians.

[A case of ANCA-associated vasculitis with esophageal stenosis and pseudodiverticulosis].

A previously healthy 67-year-old woman visited our institution because of cough that had persisted for 3 months, fever at night, left tinnitus, and hearing loss from 1 month prior. She lost 2 kg in weight over the last 6 months, and her C-reactive protein level and leukocyte count were increased. Computed tomography revealed multiple small nodules in both lung fields. She was admitted to our hospital for further examination to determine the optimal medical treatment. Because the myeloperoxidase antineutrophil cytoplasmic antibody (ANCA) titer was 132.5 U/mL and microscopic hematuria was observed, vasculitis was considered. A percutaneous kidney biopsy was performed and revealed microscopic polyangiitis. For this reason, the case was diagnosed as ANCA-associated vasculitis. Esophageal stenosis and pseudodiverticulosis were observed on upper gastrointestinal endoscopy. Pathological changes due to inflammation were observed in the biopsy and esophagography. Pulse therapy with methylprednisolone at 1,000 mg/day was administered to the patient as the first-line treatment, followed by prednisolone at 40 mg/day as remission induction treatment. Bloody urine and lung shadows disappeared, and the steroid dose was tapered at hospital discharge. The patient's hearing ability and the esophageal pathological change that was considered to be ANCA-associated vasculitis were improved. Although a few studies have reported that esophageal stenosis and pseudodiverticulosis accompany ANCA-associated vasculitis, we think that examination for the possible presence of gastrointestinal tract lesions is important.

[Autopsy case of light chain deposition disease presented by nephrotic syndrome].

An eighty-one-year-old male with lower leg edema and proteinuria was diagnosed as having nephrotic syndrome and was hospitalized for a detailed examination. Kidney biopsy and immunostaining revealed nodular glomerulosclerosis and deposition of lambda chains, respectively. Because these findings indicate the occurrence of light chain deposition disease (LCDD), the underlying disease was found to be multiple myeloma BJ-lambda. After the administration of melphalan and prednisolone, followed by further addition of zoledronic acid, the patient's nephrosis remitted. However, renal dysfunction gradually deteriorated further and hemodialysis was instituted. He eventually died of gastrointestinal bleeding and biliary infection. The period of time from the initial diagnosis to death was thirty months. Autopsy revealed pervasive infiltration of plasma cells and light chain deposition in multiple organs. The uncontrollable gastrointestinal bleeding appears to have been caused by light chain deposition in the vascular walls of a bile duct. Although medical treatment for elderly LCDD cases depends on chemotherapy alone, it is difficult to obtain a complete remission with melphalan and prednisolone, according to the literature. Reports on the validities of biological agents, such as bortezomib, are beginning to appear, and accumulation of further therapeutic experience is eagerly awaited.

Structural studies of a two-domain chitinase from Streptomyces griseus HUT6037.

Chitinase C (ChiC) from Streptomyces griseus HUT6037 was the first glycoside hydrolase family 19 chitinase that was found in an organism other than higher plants. An N-terminal chitin-binding domain and a C-terminal catalytic domain connected by a linker peptide constitute ChiC. We determined the crystal structure of full-length ChiC, which is the only representative of the two-domain chitinases in the family. The catalytic domain has an alpha-helix-rich fold with a deep cleft containing a catalytic site, and lacks three loops on the domain surface compared with the catalytic domain of plant chitinases. The chitin-binding domain is an all-beta protein with two tryptophan residues (Trp59 and Trp60) aligned on the surface. We suggest the binding mechanism of tri-N-acetylchitotriose onto the chitin-binding domain on the basis of molecular dynamics (MD) simulations. In this mechanism, the ligand molecule binds well on the surface-exposed binding site through two stacking interactions and two hydrogen bonds and only Trp59 and Trp60 are involved in the binding. Furthermore, the flexibility of the Trp60 side-chain, which may be involved in adjusting the binding surface to fit the surface of crystalline chitin by the rotation of chi2 angle, is shown.