Rotatable high-resolution ARPES system for tunable linear-polarization geometry

A rotatable high-resolution angle-resolved photoemission spectroscopy (ARPES) system has been developed to utilize tunable linear-polarization geometries on the linear undulator beamline (BL-1) at Hiroshima Synchrotron Radiation Center. By rotating the whole ARPES measurement system, the photoelectron detection plane can be continuously changed from parallel to normal against the electric field vector of linearly polarized undulator radiation. This polarization tunability enables us to identify the symmetry of the initial electronic states with respect to the mirror planes, and to selectively observe the electronic states based on the dipole selection rule in the photoemission process. Specifications of the rotatable high-resolution ARPES system are described, as well as its capabilities with some representative experimental results.

Subcutaneous Xenotransplantation of Hybrid Artificial Pancreas Encapsulating Pancreatic B Cell Line (MIN6): Functional and Histological Study

The biohybrid artificial pancreas is designed to enclose pancreatic endocrine tissues with a selectively permeable membrane that immunoisolates the graft from the host immune system, allowing those endocrine tissues to survive and control glucose metabolism for an extended period of time. The pancreatic B cell line MIN6 is established from a pancreas B cell tumor occurring in transgenic mice harboring the human insulin promoter gene connected to the SV40 T-antigen hybrid gene. It has been proven that glucose-stimulated insulin secretion in MIN6 cells retains a concentration-dependent response similar to that of normal islets. In this study, we performed the histological and functional examination of three-layer microbeads employing MIN6 cells after subcutaneous xenotransplantation to evaluate this device as bioartificial pancreas. MIN6 cells were microencapsulated in three-layer microbeads formulated with agarose, polystyrene sulfonic acid, polybrene, and carboxymethyl cellulose. Microbeads were xenogenically implanted in the subcutaneous tissue of the back of Lewis rats with streptozotocin-induced diabetes. One week after implantation, microbeads were retrieved and cultured for 24 h before the static incubation. There was no evidence of adhesion to the graft and the fibrosis in the transplantation site as determined by gross visual inspection. Microscopic examination demonstrated that retrieved microbeads maintained normal shape, containing intact MIN6 cells. Histological study showed that these MIN6 cells in the microbeads appeared to be viable without cellular infiltration within or around the microbeads. Immunohistochemical analysis of the microbeads clearly revealed the intense staining of insulin in the cytoplasm of encapsulated MIN6 cells. Insulin productivity of MIN6 cells in the microbeads is strongly suggested to be preserved. In response to 16.7 mM glucose stimulation, static incubation of microbeads 1 wk after implantation caused the 2.3 times increase in insulin secretion seen after 3.3 mM glucose stimulation (84.3 ± 10.0 vs. 37.4 ± 10.7 μU/3 × 106 cells/hr, n = 5 each, p < 0.01). This study demonstrates that three-layer microbeads encapsulating MIN6 cells retain excellent biocompatibility and maintain good insulin secretion even after subcutaneous xenotransplantation, suggesting the possible future clinical application of this unique bioartificial pancreas to subcutaneous xenotransplantation.

Improved Large-Scale Isolation of Breeder Porcine Islets: Possibility of Harvesting from Nonheart-Beating Donor

To establish a large-scale isolation procedure for adult porcine islets usable as a donor source for xenotransplantation and as a model of human islet isolation, we improved several characteristics of the conventional isolation procedure. At a slaughterhouse we first selected a breeder pig over 1.5 years old (and over 200 kg in weight) with warm ischemic time (WIT) of 15 ± 2 minutes as nonheart-beating donors. Then, we made a special enzymic mixture that consisted of collagenase S-1 (260 U/mg, NittaZelatin, Japan), collagenase P (1.86 U/ml Lyo Boehringer-Mannheim, USA), DNase (Sigma, St. Louis, Mo), Disparse (NittaZelatin, Japan), and protease inhibitor (Sigma). Third, this mixture was injected very gently into the pancreatic duct at the time of pancreatic harvesting. To prevent overdigestion of the pancreas, the mixture was first cooled to less than 10°C. Fourth, during the warm digestion of pancreas, the pancreas with the enzymic mixture was quietly put in a water bath at 37°C without mechanical shaking. Fifth, we purified the islets with a COBE 2991 cell processor by the Dextran 70 gradient method, because Dextran 70 is very cheap and has the same purification effect as the Ficoll gradient. The results of 10 consecutive breeder porcine islet isolations are reported. The total yield of isolations of islets over 50 μm in the longest diameter after staining with Dithizone (DTZ) was 85,900 ± 19,954 islets, 291,667 ± 240,452 IEQ (2,900 ± 2,324 IEQ/g). The purity of the isolated islets was very high: 90.2 ± 3.8%. Glucose stimulation during in vitro incubation induced significant insulin release from isolated breeder porcine islets. In two of the diabetic rats receiving encapsulated islets grafts using a mesh-reinforced polyvinyl alcohol hydrogel bag (MRPB), a prominent reduction in serum glucose levels (less than 200 mg/dL) persisted for 13 and 19 days, respectively, after intraperitoneal xenotransplantation islets without immunosuppression. In conclusion, we succeeded in a more efficient and less-expensive isolation of a large amount of adult porcine islets from a nonheart-beating donor.

Prolonged Effect of Troglitazone (CS-045) on Xenograft Survival of Hybrid Artificial Pancreas

Troglitazone (CS-045), a thiazolidinedione derivative, is a new oral antidiabetic agent that enhances insulin sensitivity and improves insulin responsiveness. In this study we examined the effects of CS-045 on the survival of xenografted bioartificial pancreas. Isolated rat islets were microencapsulated with three-layer agarose microcapsules (polybrene, carboxymethyl cellulose, and an agarose-polystyrene sulfonic acid mixture). Diabetes was induced by intraperitoneal injection of streptozotocin 220 mg/kg. Recipient diabetic mice were separated into two groups. In the CS-045 treated group, the recipient mice were given feed mixed with CS-045 (0.2% w/w) starting from 1 wk before transplantation up to graft failure. The mice in the control group had feed without CS-045. Three hundred microencapsulated rat islets were xenotransplanted into the intraperitoneal cavity of each recipient mouse in both groups. One month after xenotransplantation, IVGTT was performed for all recipients. Xenotransplantation of 300 rat islets in microcapsules decreased the nonfasting blood glucose levels of both groups within 2 days. In the CS-045-treated group (n = 3), the normoglycemic period lasted for more than 1 mo without administration of immunosuppressive drugs (45 ± 4.3 days). However, in the control group (n = 4), the blood glucose levels of all recipients were already elevated on day 4. In the IVGTT study, the glucose assimilation was markedly and significantly better in the CS-045-treated group than in the control group (K = 1.7 ± 0.1 vs. 0.7 ± 0.28 respectively, p <0.01). This study demonstrates that a newly developed oral antidiabetic agent, CS-045 could favorably ameliorate the diabetic state of the recipients xenotransplanted with the bioartificial pancreas, leading to an improved glucose tolerance and longer xenograft survival.

Efficacy of sucroferric oxyhydroxide treatment in Japanese hemodialysis patients and its effect on gastrointestinal symptoms

Sucroferric oxyhydroxide (SFOH) is a non-calcium, iron-based phosphate binder indicated for the treatment of hyperphosphatemia in adult dialysis patients. Studies in Japan about the side effects of SFOH treatment indicate that the incidence of diarrhea (25%) is greater while that of constipation (2.9%) is lesser in comparison to that observed upon treatment with an existing phosphate binder. In the present study, the effect of treatment with a combination of the existing phosphate binders and SFOH on the serum phosphorus level and digestive symptoms was observed in hemodialysis patients with hyperphosphatemia, which is untreatable using only the existing phosphate binders. We evaluated the serum phosphorus levels and gastrointestinal symptoms (using the gastrointestinal symptom rating scale) of 6 patients (2 men, 4 women) before and 2, 4, 6, and 8 weeks after continuous administration. The serum phosphorus levels before and 2, 4, 6, and 8 weeks after combination treatment were 7.4±1.0 mg/dL, 5.9±1.3 mg/dL, 5.8±1.5 mg/dL, 5.8±1.4 mg/dL, and 5.8±1.3 mg/dL, respectively, with significant reduction in the levels being observed 2 weeks after administration (p<0.05) and persisting even 8 weeks after continuous administration. The constipation scores before and 2, 4, and 8 weeks after drug administration were 2.39±0.85, 2.34±1.93, 2.56±1.44, and 3.28±2.19, respectively, with no changes observed during the investigation period. The diarrhea scores before and 2, 4, and 8 weeks after drug administration were 2.22±0.91, 2.06±1.16, 1.28±0.39, and 1.06±0.13 respectively. The scores improved significantly, 4 weeks after drug administration (p<0.05), and the improvement persisted, even 8 weeks after continuous administration. Thus, by using a combination of the existing phosphate binders and SFOH, we were able to reduce the serum phosphorus level in patients with hyperphosphatemia, which is untreatable using the existing phosphate binder alone, with no sign of exacerbation of the gastrointestinal symptoms despite a few contradictory case reports.

Development of a new tracer-encapsulated solid pellet injection system for more precise control of tracer-impurity-deposit location in LHD

A new tracer-encapsulated solid pellet (TESPEL) injection system has been developed additionally for the LHD heliotron. This system has three-dimensionally bended guide tubes, which allows us to inject the TESPEL obliquely on a poloidal cross-section of the LHD plasma. Consequently, this system enables us to control a tracer-impurity-deposited location more precisely. Moreover, this system can make it possible for the tracer impurity to be deposited even only inside the ergodic region (outside a last closed flux surface of the LHD plasma). A stereoscopic fast camera system has been also developed for capturing a three-dimensional TESPEL trajectory.

Calibrations of the LHD Thomson scattering system

The Thomson scattering diagnostic systems are widely used for the measurements of absolute local electron temperatures and densities of fusion plasmas. In order to obtain accurate and reliable temperature and density data, careful calibrations of the system are required. We have tried several calibration methods since the second LHD experiment campaign in 1998. We summarize the current status of the calibration methods for the electron temperature and density measurements by the LHD Thomson scattering diagnostic system. Future plans are briefly discussed.

Tracer-Encapsulated Solid Pellet (TESPEL) injection system for the TJ-II stellarator

A tracer-encapsulated solid pellet (TESPEL) injection system for the TJ-II stellarator was recently developed. In order to reduce the time and cost for the development, we combined a TESPEL injector provided by National Institute for Fusion Science with an existing TJ-II cryogenic pellet injection system. Consequently, the TESPEL injection into the TJ-II plasma was successfully achieved, which was confirmed by several pellet diagnostics including a normal-incidence spectrometer for monitoring a tracer impurity behavior.

Validations of calibration-free measurements of electron temperature using double-pass Thomson scattering diagnostics from theoretical and experimental aspects

This paper evaluates the accuracy of electron temperature measurements and relative transmissivities of double-pass Thomson scattering diagnostics. The electron temperature (T_e) is obtained from the ratio of signals from a double-pass scattering system, then relative transmissivities are calculated from the measured T_e and intensity of the signals. How accurate the values are depends on the electron temperature (T_e) and scattering angle (θ), and therefore the accuracy of the values was evaluated experimentally using the Large Helical Device (LHD) and the Tokyo spherical tokamak-2 (TST-2). Analyzing the data from the TST-2 indicates that a high T_e and a large scattering angle (θ) yield accurate values. Indeed, the errors for scattering angle θ = 135° are approximately half of those for θ = 115°. The method of determining the T_e in a wide T_e range spanning over two orders of magnitude (0.01-1.5 keV) was validated using the experimental results of the LHD and TST-2. A simple method to provide relative transmissivities, which include inputs from collection optics, vacuum window, optical fibers, and polychromators, is also presented. The relative errors were less than approximately 10%. Numerical simulations also indicate that the T_e measurements are valid under harsh radiation conditions. This method to obtain T_e can be considered for the design of Thomson scattering systems where there is high-performance plasma that generates harsh radiation environments.

Semi-mechanistic autoinduction model of midazolam in critically ill patients: population pharmacokinetic analysis

WHAT IS KNOWN AND OBJECTIVE

Midazolam (MDZ) is commonly used for sedating critically ill patients. The daily dose required for adequate sedation increases in increments over 100 h after administration. The objectives of this study were to characterize the MDZ pharmacokinetics in critically ill patients and to describe the phenomenon of increasing daily dose by means of population pharmacokinetic analysis.

METHODS

Data were obtained from 30 patients treated in an intensive care unit. The patients received MDZ intravenously as a combination of bolus and continuous infusion. Serum MDZ concentration was assayed by high-performance liquid chromatography. Population pharmacokinetic analysis was performed using the NONMEM software package. The alteration of clearance unexplained by demographic factors and clinical laboratory data was described as an autoinduction of MDZ clearance using a semi-mechanistic pharmacokinetic-enzyme turnover model.

RESULTS AND DISCUSSION

The final population pharmacokinetic model was a one-compartment model estimated by incorporating a semi-mechanistic pharmacokinetic-enzyme turnover model for clearance, taking autoinduction into account. A significant covariate for MDZ clearance was total bilirubin. An increase in total bilirubin indicated a reduction in MDZ clearance. From simulation using the population pharmacokinetic parameters obtained in this study, MDZ clearance increased 2·3 times compared with pre-induced clearance 100 h after the start of 12·5 mg/h continuous infusion.

WHAT IS NEW AND CONCLUSION

Autoinduction and total bilirubin were significant predictors of the clearance of MDZ in this population. Step-by-step dosage adjustment using this population pharmacokinetic model may be useful for establishing a MDZ dosage regimen in critically ill patients.

Modified total meso-pancreatoduodenum excision with pancreaticoduodenectomy as a mesopancreatic plane surgery in borderline resectable pancreatic cancer

BACKGROUND

A superior mesenteric artery (SMA)-first approach has been considered to be an efficient technique in pancreaticoduodenectomy when the SMA is a factor of borderline resectable pancreatic head cancer (BRPHC). However, this excellent procedure has limitations in terms of tumor resection with an intact coverage including the pancreatic tumor and the tumor-draining lymphovascular systems and the ability to achieve a complete regional lymphadenectomy.

METHODS

A modified mesenteric plane procedure has been developed that provides improved regional lymphadenectomy and permits adjustment of the surgical approach, which is based on the direction of the tumor infiltration.

RESULTS

Of 55 patients taken to surgery, 19 had peritoneal dissemination and/or liver metastasis at staging laparoscopy, and the procedure revealed tumor infiltration to the SMA and/or hepatic artery (HA) in 4 patients. Finally, 32 patients with BRPHC have undergone the procedure between April 2009 and June 2015. Twenty-four of 32 patients (75.0%) had negative resection margins, and the median number of lymph nodes harvested was 34. Lymph nodes around the SMA tested positive for metastasis in 13 patients (40.6%), and those around the HA tested positive for metastasis in 7 patients (21.9%). Complications occurred in 14 patients (43.7%), with no perioperative mortality. Overall survival rates were 65.3% at 1 year and 35.2% at 3 years.

CONCLUSIONS

Short-term results with the procedure may encourage surgical management for BRPHC.