Closed-cycle cold helium magic-angle spinning for sensitivity-enhanced multi-dimensional solid-state NMR

AbstractMagic-angle spinning (MAS) NMR is a powerful tool for studying molecular structure and dynamics, but suffers from its low sensitivity. Here, we developed a novel helium-cooling MAS NMR probe system adopting a closed-loop gas recirculation mechanism. In addition to the sensitivity gain due to low temperature, the present system has enabled highly stable MAS (vR=4–12kHz) at cryogenic temperatures (T=35–120K) for over a week without consuming helium at a cost for electricity of 16kW/h. High-resolution 1D and 2D data were recorded for a crystalline tri-peptide sample at T=40K and B0=16.4T, where an order of magnitude of sensitivity gain was demonstrated versus room temperature measurement. The low-cost and long-term stable MAS strongly promotes broader application of the brute-force sensitivity-enhanced multi-dimensional MAS NMR, as well as dynamic nuclear polarization (DNP)-enhanced NMR in a temperature range lower than 100K

In-cell NMR as a sensitive tool to monitor physiological condition of Escherichia coli

Sugiki, T., Yamaguchi, Y., Fujiwara, T. et al. In-cell NMR as a sensitive tool to monitor physiological condition of Escherichia coli. Sci Rep 10, 2466 (2020). https://doi.org/10.1038/s41598-020-59076-2

Robust folding of a de novo designed ideal protein even with most of the core mutated to valine

Rie Koga, Mami Yamamoto, Takahiro Kosugi, Naohiro Kobayashi, Toshihiko Sugiki, Toshimichi Fujiwara, Nobuyasu Koga, Robust folding of a de novo designed ideal protein even with most of the core mutated to valine. Proceedings of the National Academy of Sciences. 117 (49), 31149-31156 (2020). DOI: 10.1073/pnas.2002120117

Precancerous Pyloric Gland Metaplasia in the Biliary Epithelium Associated with Congenital Biliary Dilatation in a Three-Month-Old Infant

Pyloric gland metaplasia in the biliary epithelium is a precancerous lesion and has been confirmed in patients with congenital biliary dilatation presenting with overt biliary tract cancer. A patient was found to have an intra-abdominal cyst on fetal ultrasonography and was born at 37 weeks of gestation with a body weight of 2,636 g. Abdominal distension and repeated vomiting appeared 2 days after birth. Congenital biliary dilatation was diagnosed by imaging, wherein the common bile duct was enlarged to 9–10 cm in size, and the surrounding organs were extensively compressed; however, there was no sign of pancreatitis or cholangitis. Biliary drainage was performed through the gallbladder at 6 days of age, but it was insufficient because of the narrow and twisted cystic duct and changed to common bile duct at 18 days to relieve the compression. Because the body weight gain was poor due to loss of large amount of bile, the dilated bile duct and gallbladder were resected and hepatic duct Roux-Y jejunostomy was performed at 115 days of age with 4,500 g of body weight. Intraoperative imaging showed a pancreaticobiliary maljunction, and the pancreatic enzyme activities of the bile in the biliary system were remarkably elevated. Histopathological examination revealed pyloric gland metaplasia in the gallbladder epithelium and cystic duct. The patient is now over 2 years old and has been doing well without any complications. Based on our experience, precancerous pyloric gland metaplasia of the biliary epithelium may already occur even in a 3-month-old infant presenting with congenital biliary dilatation

The crystal structure of the plant small GTPase OsRac1 reveals its mode of binding to NADPH oxidase

This research was originally published in Journal of Biological Chemistry. Ken-ichi Kosami, Izuru Ohki, Minoru Nagano, Kyoko Furuita, Toshihiko Sugiki, Yoji Kawano, Tsutomu Kawasaki, Toshimichi Fujiwara, Atsushi Nakagawa, Ko Shimamoto and Chojiro Kojima. The crystal structure of the plant small GTPase OsRac1 reveals its mode of binding to NADPH oxidase. Journal of Biological Chemistry. 2014; 289, 28569-28578. © the American Society for Biochemistry and Molecular Biology

Ruptured Small Intestinal Stromal Tumor Causing Concurrent Gastrointestinal and Intra-Abdominal Hemorrhage: A Case Report

Gastrointestinal stromal tumors (GISTs) originate from mesenchymal cells throughout the gastrointestinal tract. A common symptom is gastrointestinal hemorrhage; intra-abdominal hemorrhage is relatively rare. There are few reports of GIST presenting with both types of hemorrhage concurrently. A 77-year-old man was admitted to our hospital because of melena and anemia (Hb: 4.7 g/dL). Computed tomography revealed a small bowel tumor and high-density fluid in both the small intestine and the pelvic floor. We diagnosed a small intestinal tumor with concurrent gastrointestinal and intra-abdominal hemorrhage, and performed emergency surgery. The tumor arose from the small intestine and was ruptured. We found hemorrhage in the pelvic cavity and performed partial small intestine resection. Pathological findings revealed that the tumor was positive for c-Kit protein and was diagnosed as GIST. The patient was discharged from the hospital on postoperative day 9 and received imatinib 1 month postoperatively. We experienced a very rare case of ruptured GIST originating from the small intestine associated with both gastrointestinal and intra-abdominal hemorrhage. We also reviewed the relevant literature

Clinical Significance of Serum Antithrombin III Activity After Hepatectomy for Hepatocellular Carcinoma

[Background] As antithrombin III (AT-III) is produced in the hepatocytes, its serum activity decreases at the time of liver failure, in addition to ischemia reperfusion injury, vascular endothelial dysfunction, and disseminated intravascular coagulation (DIC). Here, we examined whether the serum AT-III value after hepatectomy could be a prognostic factor for hepatocellular carcinoma (HCC). [Methods] Of 141 patients who underwent hepatectomy for HCC, data for 101 patients in whom serum AT-III activity was measured on the first postoperative day were extracted. Patients with serum AT-III activity > 50% and ? 50% were assigned to high value (72 cases) and low value (29 cases) groups, respectively. We examined the clinical and prognostic differences between these two groups. [Results] The average age of enrolled patients (83 men and 18 women) was 68.0 years. The 5-year overall survival rate was 88% and 60% in the high and low value groups, respectively (P < 0.01). Furthermore, the 2-year relapse-free survival rate was 71% and 54% in the high and low value groups, respectively (P = 0.03). [Conclusion] This is the first study to demonstrate that serum AT-III levels on the first postoperative day may serve as a prognostic factor in HCC patients

Platelet-to-Lymphocyte Ratio Multiplied by the Cytokeratin-19 Fragment Level as a Predictor of Pathological Response to Neoadjuvant Chemotherapy in Esophageal Squamous Cell Carcinoma

[Background] The standard treatment for resectable advanced esophageal squamous cell carcinoma in Japan is surgery followed by neoadjuvant chemotherapy, and it is important to predict the effect of neoadjuvant chemotherapy before treatment. Therefore, this study aims to extract conventional blood examination data, such as tumor markers and/or inflammatory/nutritional index levels, that can predict the pathological response of patients with esophageal squamous cell carcinoma to neoadjuvant chemotherapy. [Methods] We retrospectively analyzed the medical records of 66 patients with thoracic esophageal squamous cell carcinoma who received neoadjuvant chemotherapy, followed by curative esophagectomy at Tottori University Hospital between June 2009 and December 2019. [Results] We demonstrated that the product of the platelet-to-lymphocyte ratio (PLR) multiplied by the cytokeratin-19 fragment (CYFRA) level, which was termed “PLR-CYFRA,” is the most accurate indicator that predicts the pathological response to neoadjuvant chemotherapy, with the highest area under the curve [0.795 (95% confidence interval: 0.665–0.925), P < 0.001] in receiver operating characteristic analyses. Therefore, we divided patients into the PLR-CYFRALow (< 237.6, n = 21) and PLR-CYFRAHigh (≥ 237.6, n = 45) groups and found that the percentage of PLR-CYFRALow was significantly higher in patients with a better pathological response (P < 0.001). Furthermore, patients with good pathological response had significantly better prognoses in terms of disease-specific survival (P = 0.014), recurrence-free survival (P = 0.014), and overall survival (P = 0.032). In the multivariate analysis, PLR-CYFRA was an independent predictor of the pathological response of patients with esophageal squamous cell carcinoma to neoadjuvant chemotherapy (P = 0.002). [Conclusion] Pretreatment PLR-CYFRA might be a useful and simple tool that predicts the pathological effect of neoadjuvant chemotherapy in esophageal squamous cell carcinoma

Modern Technologies of Solution Nuclear Magnetic Resonance Spectroscopy for Three-dimensional Structure Determination of Proteins Open Avenues for Life Scientists

Nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for structural studies of chemical compounds and biomolecules such as DNA and proteins. Since the NMR signal sensitively reflects the chemical environment and the dynamics of a nuclear spin, NMR experiments provide a wealth of structural and dynamic information about the molecule of interest at atomic resolution. In general, structural biology studies using NMR spectroscopy still require a reasonable understanding of the theory behind the technique and experience on how to recorded NMR data. Owing to the remarkable progress in the past decade, we can easily access suitable and popular analytical resources for NMR structure determination of proteins with high accuracy. Here, we describe the practical aspects, workflow and key points of modern NMR techniques used for solution structure determination of proteins. This review should aid NMR specialists aiming to develop new methods that accelerate the structure determination process, and open avenues for non-specialist and life scientists interested in using NMR spectroscopy to solve protein structures. Keywords: Nuclear magnetic resonance (NMR) spectroscopy, Solution NMR, Automation, Protein, Structure determination, Validatio