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This article provides an overview of the design methodology used to develop a conceptual set of reactivity control mechanism of a micro reactor based on the U-Battery. The U-Battery is based on remote deployment and therefore it is favourable to provide a long fuel lifecycle. This is achieved by implementing a high fissile loading content, which proves challenging when considering reactivity control methods. This article follows the design methodology used to overcome these issues, with an emphasis on a new concept of a moveable moderator which utilises the size of the U-Battery as a small reduction in moderation provides a significant reduction in reactivity. The latest work on this project sees the moveable moderator investigated during a depressurised loss of forced coolant accident, where a reduction of moderator volume increases the maximum fuel temperature experienced. The overall conclusion is that the maximum fuel temperature is not significantly increased (4 K) due to the central reflector region relatively lower volumetric heat capacity compared to that of whole core. However, a small temperature increase is observed immediately after the transient due to the central reflector removal because it reaches energy equilibrium with the fuel region faster.

Background It is unclear how effective recombinant thrombomodulin (rTM) treatment is in disseminated intravascular coagulation (DIC) during the perioperative period of gastrointestinal and hepato-biliary-pancreatic surgery. The current study aimed to evaluate the therapeutic outcomes of rTM for perioperative DIC.Methods We enrolled 100 consecutive patients diagnosed with perioperative DIC after gastrointestinal surgery, and hepato-biliary-pancreatic including emergency procedures, between January 2012 and May 2021. Patients received routine rTM treatment immediately after DIC diagnosis. Then, the DIC, Sequential Organ Failure Assessment (SOFA), and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were calculated and used for evaluation. The outcomes of rTM treatment and the predictors of survival were evaluated.Results The causative diseases of DIC were as follows: perforated peritonitis, n = 38; intestinal ischemia, n = 23; intra-abdominal abscess, n = 13; anastomotic leakage, n = 7; pneumonia, n = 7; cholangitis, n = 4; and others, n = 6. The 30-day mortality rate was 18.0%. There were significant differences in the platelet count (13.78 vs 10.41, P = .032) and the SOFA score (5.22 vs 9.89, P<.0001) at the start of DIC treatment between the survivor and non-survivor groups (day 0). The survivor group had a significantly lower DIC score (3.13 vs 4.93, P = .0006) and SOFA score (4.94 vs 12.14, P < .0001) and a higher platelet count (13.50 vs 4.34, P < .0001) than the non-survivor group on day 3.Conclusions Comprehensive and systemic treatment is fundamentally essential for DIC, in which rTM may play an important role in the treatment of perioperative DIC.

Colorectal perforation is a serious disease with high mortality requiring emergency surgery. This study aimed to evaluate the role of the endotoxin activity assay (EAA) to assess the severity in patients admitted to the intensive care unit after emergency surgeries for colorectal perforations. Patients were divided into high (EAA ≥.4) and low (EAA <.4) groups based on the EAA levels, and the correlation between the EAA values and clinical variables related to the severity was evaluated. The SOFA scores were significantly higher in the high group than those in the low group. The high EAA value persisted even after 48 hours and extended the ICU length of stay. These results suggest that EAA may be a potential biomarker to assess severity and useful as one of the instrumental in predicting the outcomes for colorectal perforation patients.

Indocyanine green fluorescence imaging (ICG-FI)—a sensitive tool for detecting tumor localization in laparoscopic surgery—produces false positive results for benign liver tumors. This report is the first case of hepatic angiomyolipoma (HAML) treated laparoscopically with ICG-FI. We present the case of a 31-year-old woman with a liver tumor that was a 13-mm mass in the anterior superior segment. Though a benign tumor was suspected, malignant potential could not be ruled out. Therefore, minimally invasive laparoscopic resection using ICG-FI was planned. ICG, intravenously injected preoperatively, revealed the tumor’s existence. Pure laparoscopic hepatectomy with ICG-FI was performed for excisional biopsy, during which the tumor was resected with adequate surgical margins, followed by histological confirmation of HAML. In conclusion, it is suggested that laparoscopic resection with ICG-FI is an effective minimal invasive surgery for tumors that are difficult to detect, such as HAML, leading to a safe surgical margin.

1550 nm wavelength photonic-crystal surface-emitting lasers (PCSELs) are attractive for optical communication and eye-safe sensing applications. In this study, we present InP-based PCSELs featuring a double-lattice photonic-crystal structure designed for high-power single-mode operation at a wavelength of 1550 nm. These PCSELs demonstrate output powers exceeding 300 mW under continuous-wave conditions at 25 °C. Additionally, highly stable single-mode oscillation with a side-mode suppression ratio of over 60 dB is verified at temperatures from 15 °C to 60 °C. Measurement and simulation of photonic band structures reveal the impacts of the threshold gain margin and optical coupling coefficient on the single-mode stability.

Background Decreased pancreatic volume (PV) is a predictive factor for diabetes mellitus (DM) after surgery. There are few reports on PV and endocrine function pre- and post-surgery. We investigated the correlation between PV and insulin secretion.Methods Seventeen patients underwent pancreaticoduodenectomy (PD) Pre- and post-surgery PV and C-peptide index (CPI) measurements were performed. Additionally, the correlation between PV and CPI was analyzed.Results The mean preoperative PV (PPV) was 55.1 ± 31.6 mL, postoperative remnant PV (RPV) was 25.3±17.3 mL, and PV reduction was 53%. The mean preoperative C-peptide immunoreactivity (CPR) was 1.39 ± .51 and postoperative CPR was .85±.51. The mean preoperative CPI was 1.29±.72 and postoperative CPI was .73 ± .48. Significant correlations were observed between RPV and post CPR (ρ = .507, P = .03) and post CPI (ρ = .619, P = .008).Discussion There was a significant correlation between RPV and CPI after PD. A smaller RPV resulted in lower insulin secretion ability, increasing the potential risk of new-onset DM after PD.

IMPORTANCE: In distal pancreatectomy (DP), the splenic vein is isolated from the pancreatic parenchyma prior to being ligated and divided to prevent intra-abdominal hemorrhage from the splenic vein stump with pancreatic fistula (PF). Conversely, dissecting the splenic vein with the pancreatic parenchyma is easy and time-saving. OBJECTIVE: To establish the safety of combined division of the splenic vein compared with separate division of the splenic vein. DESIGN, SETTING, AND PARTICIPANTS: This study was designed as a multicenter prospective randomized phase 3 trial. All results were analyzed using the modified intent-to-treat set. Patients undergoing DP for pancreatic body and tail tumors were eligible for inclusion. Patients were randomly assigned between August 10, 2016, and July 30, 2019. INTERVENTIONS: Patients were centrally randomized (1:1) to either separate division of the splenic vein or combined division of the splenic vein. MAIN OUTCOMES AND MEASURES: The primary end point was the incidence of grade B/C PF, and the incidence of intra-abdominal hemorrhage was included as one of the secondary end points. RESULTS: A total of 318 patients were randomly assigned, and 2 patients were excluded as ineligible. Of the 316 remaining patients, 150 (50.3%) were male. The modified intent-to-treat population constituted 159 patients (50.3%) in the separate division group and 157 patients (49.7%) in the combined division group. In the modified intent-to-treat set, the proportion of grade B/C PF in the separate division group was 27.1% (42 of 155) vs 28.6% (44 of 154) in the combined division group (adjusted odds ratio, 1.108; 95% CI, 0.847-1.225; P = .047), demonstrating noninferiority of the combined division of the splenic vein against separate division. The incidence of postoperative intra-abdominal hemorrhage in the 2 groups was identical at 1.3%. CONCLUSIONS AND RELEVANCE: This study demonstrated noninferiority of the combined division of the splenic vein compared with separate division of the splenic vein regarding safety. Thus, isolating the splenic vein from the pancreatic parenchyma is deemed unnecessary. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02871804

Laparoscopic total gastrectomy (LTG) for remnant gastric cancer (RGC) requires advanced techniques due to severe postoperative adhesions and anatomic changes. We performed LTG in 2 patients with RGC using intraoperative indocyanine green (ICG) fluorescence imaging. Both cases previously underwent distal gastrectomy with Billroth-I reconstruction for gastric cancer and were subsequently diagnosed with early-stage gastric cancer of the remnant stomach. Indocyanine green (2.5 mg/body) was administered intravenously during surgery. The liver and common bile duct were clearly visualized during surgery using near-infrared fluorescence laparoscopy, and the adhesions between the hepatobiliary organs and remnant stomach were safely dissected. Laparoscopic total gastrectomy was successfully performed without complications, and the postoperative course was uneventful in both cases. Intraoperative real-time ICG fluorescence imaging allows clear visualization of the liver and common bile duct and can be useful in LTG for RGC with severe adhesions.

Supplemental digital content is available in the text.

Background: Several reports indicate that extracellular volume predicted by bioimpedance analysis method is associated with hydration status of hemodialysis patients.Theory: Fundamentally, uric acid does not cross cell membranes by simple diffusion, either by facilitated diffusion or by active transport. In addition, uric acid cannot move through cell membranes in most tissues other than those involved in uric acid excretion. These facts support the interpretation that uric acid distribution volume would therefore correlate with extracellular volume.Methods: We examined correlation between uric acid distribution volume calculated by uric acid mass-balance modeling from regular blood test results and extracellular volume predicted by bioimpedance analysis predicted by BCM (Fresenius Medical Care) in 53 patients.Results: There was a significant correlation between uric acid distribution volume (x) and extracellular volume predicted by bioimpedance analysis (y): y= 0.69x+ 3.39, r2= 0.61, p< 0.0001. Bland–Altman analysis showed systematic error for uric acid distribution volume versus extracellular volume predicted by bioimpedance analysis (mean difference between uric acid distribution volume and extracellular volume predicted by bioimpedance analysis was 0.94 L, 95% confidence interval of difference was −3.29 to 5.17 L).Conclusion: Uric acid distribution volume calculated by uric acid mass-balance modeling from regular blood test results may be an alternative marker of extracellular volume predicted by bioimpedance analysis.

Background: We introduce a novel operative technique to dissect lymph nodes adjacent to the recurrent laryngeal nerve, referred to as the “native tissue preservation” technique. Using this technique, there was no damage to the recurrent laryngeal nerve, which is maintained in its anatomical position. Methods: From September 2016 to December 2018, minimally invasive esophagectomy was performed in the left lateral decubitus position in 87 patients with esophageal cancer. The native tissue preservation technique for lymphadenectomy around the recurrent laryngeal nerve was used, and all patients were evaluated for recurrent laryngeal nerve paralysis. Results: Minimally invasive esophagectomy was completed in all patients without conversion to thoracotomy. Although an extended lymphadenectomy was performed in all patients, there were no grade II or higher complications (Clavien–Dindo classification) and no incidence of recurrent laryngeal nerve paralysis. Conclusion: The native tissue preservation technique may reduce the incidence of recurrent laryngeal nerve paralysis after minimally invasive esophagectomy with radical lymph node dissection.

We propose a wearable system using oxide semiconductor (OS) transistors, which enables reduced static power of a dynamic logic device utilizing OS transistors and resulting longer continuous use of a wearable device. We fabricated a wearable‐watch‐oriented device. The results indicated that the static power could be reduced by 51%.

BackgroundOutcomes of endovascular treatment for acute ischemic stroke depend on the time interval from onset to reperfusion. Although the centralized ‘mothership’ method is considered preferable, the required transportation time increases the risk that a patient with a stroke may not receive intravenous or endovascular therapy. In contrast, ‘drive and retrieve’ describes a system wherein doctors from comprehensive stroke centers travel to primary stroke centers and provide endovascular treatment for acute ischemic stroke.ObjectiveTo describe the drive and retrieve system and verify the effects of this new collaboration on outcomes in patients with acute ischemic stroke among facilities.MethodsThis non-randomized, single-arm study retrospectively analyzed patients who met the inclusion criteria for endovascular treatment provided through a drive and retrieve system. Among the 122 patients treated by this system, we analyzed the time of onset to recanalization as the primary outcome. We also analyzed the efficacy of the drive and retrieve system using geographic information system analysis.ResultsThe median time from onset to recanalization was 229 min (IQR 170–307 min, 95% CI 201 to 252 min). The upper limit of the 95% CI for the time from onset to recanalization was shorter than the median times reported in two previous trials. Geographic information system analysis revealed an upward trend in the population coverage rate in each secondary medical area after the drive and retrieve method was introduced.ConclusionThe drive and retrieve method may be an effective form of cooperation between facilities located within 1 hour of a comprehensive stroke center.

Indocyanine green (ICG) fluorescence-guided surgery is a real-time navigation technology for tumor detection, securing surgical margins, segmentation mapping, and cholangiography in liver surgery [1]. According to recent reports, the Medical Imaging Projection System (MIPS) may be a useful new real-time navigation technology for open anatomical liver resection [2]. However, the efficacy of MIPS for tumor identification, cholangiography, and securing surgical margins is uncertain. In this report, we introduce MIPS-assisted liver resection for real-time navigation during simultaneous tumor identification, cholangiography, and securing surgical margins.

Supplemental Digital Content is available in the text.

An oxide semiconductor (OS) display system built with normally-off devices, nonvolatile OS LSI and an OS display, is proposed. The power consumption of the system is reduced by the nonvolatile OS LSI performing power gating without vanishing setting data when the OS display is in an idling stop (IDS) mode.

A display controller used in an oxide-semiconductor (OS) display was fabricated based on OS technology. Setting parameters were stored in non-volatile registers comprising OS FETs; thus, power shutdown and restart of the power supply along with “idling stop” driving are possible. The power consumption was reduced by 75%. Optimal setting parameters can also be obtained with AI.

Oxide semiconductor field-effect transistors (OSFETs) are characterized by their extremely low off-state current. By fabricating both a display and peripheral large-scale integrated circuits with OSFETs, the components can be driven in a normally off manner, thus enabling a display system with low power consumption. We explore herein the feasibility of a more energy-efficient display system, which is achieved by predicting changes in image data and thus more efficiently controlling the power-gate timing. This is done by using an artificial neural network.

Nerve growth factor (NGF), which plays important roles in promoting growth and differentiation of nerve cells, has recently been reported as a regulator in pancreatic cells in terms of insulin releasing function. In this study, we examined whether NGF stimulation would promote islet graft survival and function in islet transplantation.

Although the somatostatin analog octreotide (OCT) has been used for uncontrollable insulinoma, the mechanism involved is still unknown. The aim of this study was to elucidate the therapeutic effect of OCT for insulinoma.

•Accurate segment boundary visualization is crucial for anatomical liver resection.•Indocyanine green (ICG) fluorescence imaging is a practical option for liver mapping.•ICG injection into cancer-bearing portal pedicles can be used for liver mapping.•This procedure is a significant challenge under pneumoperitoneum conditions.•A holographic display supports ICG liver mapping as valuable guidance.

While islet transplantation is considered a useful therapeutic option for severe diabetes mellitus (DM), the outcome of this treatment remains unsatisfactory. This is largely due to the damage and loss of islets in the early transplant stage. Thus, it is important to monitor the condition of the transplanted islets, so that a treatment can be selected to rescue the islets from damage if needed. Recently, numerous trials have been performed to investigate the efficacy of different imaging modalities for visualizing transplanted islets. Positron emission tomography (PET) and magnetic resonance imaging (MRI) are the most commonly used imaging modalities for this purpose. Some groups, including ours, have also tried to visualize transplanted islets by ultrasonography (US). In this review article, we discuss the recent progress in islet imaging.

AbstractA 50-year-old woman had undergone left nephrectomy for renal cell carcinoma 13 years previously. Ten years later, a solitary metastatic tumor had been detected in the pancreatic tail and she had undergone subsequent resection of the pancreatic tail and spleen. Three years after surgery, she was admitted to our hospital for severe anemia resulting from gastrointestinal tract bleeding. Esophagogastroduodenoscopy revealed a 3-cm solid tumor at the oral side of the papilla of Vater. Histology of the bioptic duodenal tissue revealed inflammatory granulation without malignancy. Computed tomography showed a well-contrasted hypervascular tumor in the descending portion of the duodenum. We diagnosed the patient with metachronous duodenal metastasis of renal cell carcinoma and performed a pancreaticoduodenectomy. An ulcerated polypoid mass was detected at the oral side of the papilla of Vater. Histology revealed clear cell carcinoma coated by granulation tissue across the surface of the tumor. Immunohistology demonstrated that the cells were positive for vimentin, CD10 and epithelial membrane antigen and negative for CK7. After a repeated pancreatectomy, the patient had no symptoms of gastrointestinal bleeding and maintained good glucose tolerance without insulin therapy because the remnant pancreas functioned well. In conclusion, for the diagnosis of patients who have previously undergone nephrectomy and present with gastrointestinal bleeding, the possibility of metastasis to the gastrointestinal tract, including the duodenum, should be considered. With respect to surgical treatment, the pancreas should be minimally resected to maintain a free surgical margin during the first surgery taking into account further metachronous metastasis to the duodenum and pancreas.© 2013 S. Karger AG, Basel

A pass gate (PG) configured with a configuration memory (CM) composed of a c-axis aligned crystalline In-Ga-Zn-O (CAAC-IGZO) FET and a pass transistor composed of an NMOS FET is applied to a multi-context routing switch (MC-RS) of a dynamically reconfigurable programmable logic device (DRPLD) based on multi-context architecture (MC-DRPLD). The proposed PG (OS PG) requires fewer transistors than a conventional PG configured with an SRAM cell served as a CM (SRAM PG). A MC-RS configured with the OS PG (OS MC-RS) has enabled its layout area to be 40% less than that of a MC-RS configured with the SRAM PG (SRAM MC-RS). Further, the delays of the MC-RSs with 2 to 16 contexts have been reduced by 24% to 37%. The MC-DRPLD including the OS MC-RS can switch contexts in one clock (50 nsec) at a clock frequency of 20 MHz, which enables dynamic reconfiguration at high speed.

A method for preparing an aqueous dispersion of titanium dioxide (TiO2) nanoparticles by generating plasma on the liquid surface was developed. The plasma was generated between the tip of a needle electrode in the gas phase and the liquid surface. A 0.01 wt % aqueous dispersion of TiO2was prepared by plasma treatment with ultrasonication. Dynamic light scattering measurements indicated that the average TiO2nanoparticle sizes in the dispersions with plasma treatment in air and Ar atmosphere were approximately 150 and 180 nm, respectively. Although the pH of the dispersion prepared by Ar plasma treatment was fairly close to the isoelectric point of TiO2, the dispersion maintained a finely dispersed state. The surface potentials of TiO2nanoparticles in the dispersions treated with plasma were confirmed to be positively charged. This suggests that the dispersions formed by plasma treatment were stabilized by electrostatic repulsion between the particles.

The glutamate hypothesis of schizophrenia suggests that hypofunction of N-methyl-D-aspartate (NMDA) receptors may be critical for schizophrenic symptoms; therefore, pharmacological approaches that enhance NMDA function may be beneficial for the treatment of schizophrenia. Several lines of evidence indicate that NMDA and metabotropic glutamate (mGlu) 5 receptors are closely associated signaling partners and that a selective mGlu5 receptor agonist might provide a viable approach for increasing NMDA receptor function in the treatment of schizophrenia. The orthosteric binding sites across members of the mGlu receptor subtype for a particular endogenous ligand are often highly conserved, making it difficult to achieve high selectivity for the specific mGlu5 receptor. The advanced currents of drug discovery have developed multiple highly selective allosteric modulators of mGlu5 receptor. In the present review, we provide an update of the recent patents and development of positive allosteric modulators of the mGlu5 receptor and explore their therapeutic potential for schizophrenia.

Background/Aims:Patients with intraductal papillary-mucinous neoplasm (IPMN) of the pancreas are likely to have a better prognosis than those with conventional pancreatic ductal adenocarcinoma. Recently there have been some reports on extrapancreatic malignant neoplasms (EPM) occurring in patients with IPMN. The purpose of this study was to discover the characteristic features of IPMN with EPM compared with IPMN without EPM. Methods:61 patients with IPMN who underwent surgery at Tohoku University Hospital between 1988 and 2006 were retrospectively analyzed. Results:The 61 patients with IPMN in this study comprised 25 with intraductal papillary-mucinous adenomas (IPMA) and 36 with intraductal papillary-mucinous carcinomas (IPMC) including 6 with invasive carcinomas. Synchronous and metachronous EPM were observed in 15 out of the 61 patients (24.6%). Three of these patients, including 2 with IPMA and 1 with invasive carcinoma associated with IPMC, died of the EPM. None of the features, including sex, age, smoking, family history, macroscopic types (main duct type or branch duct type), histological types (gastric, intestinal, pancreatobiliary or oncocytic), and aberrant expression of molecules including CDKN2A, TP53, SMAD4 and DUSP6, except for the histological diagnoses were associated with the occurrence of EPM, i.e., the EPM occurred more often in patients with IPMA (10 out of 25) than in those with IPMC (5 out of 36) in our series (p = 0.0199 by the ?2test, p = 0.0330 by Fisher's exact probability test, p = 0.0422 by Yates' correction). Conclusion:Patients with IPMA were more likely to have EPM than those with IPMC. Patients with IPMA are usually expected to have a fair prognosis but EPM could be fatal in some of them, so it must be noted during follow-up.

Background/Aims: Patients with intraductal papillary-mucinous neoplasm (IPMN) of the pancreas are likely to have a better prognosis than those with conventional pancreatic ductal adenocarcinoma. Recently there have been some reports on extrapancreatic malignant neoplasms (EPM) occurring in patients with IPMN. The purpose of this study was to discover the characteristic features of IPMN with EPM compared with IPMN without EPM. Methods: 61 patients with IPMN who underwent surgery at Tohoku University Hospital between 1988 and 2006 were retrospectively analyzed. Results: The 61 patients with IPMN in this study comprised 25 with intraductal papillary-mucinous adenomas (IPMA) and 36 with intraductal papillary-mucinous carcinomas (IPMC) including 6 with invasive carcinomas. Synchronous and metachronous EPM were observed in 15 out of the 61 patients (24.6). Three of these patients, including 2 with IPMA and 1 with invasive carcinoma associated with IPMC, died of the EPM. None of the features, including sex, age, smoking, family history, macroscopic types (main duct type or branch duct type), histological types (gastric, intestinal, pancreatobiliary or oncocytic), and aberrant expression of molecules including CDKN2A, TP53, SMAD4 and DUSP6, except for the histological diagnoses were associated with the occurrence of EPM, i.e., the EPM occurred more often in patients with IPMA (10 out of 25) than in those with IPMC (5 out of 36) in our series (p = 0.0199 by the χ2test, p = 0.0330 by Fisher’s exact probability test, p = 0.0422 by Yates’ correction). Conclusion: Patients with IPMA were more likely to have EPM than those with IPMC. Patients with IPMA are usually expected to have a fair prognosis but EPM could be fatal in some of them, so it must be noted during follow-up. and IAP

Intraductal papillary-mucinous neoplasm (IPMN) of the pancreas encompasses a spectrum of neoplasms with both morphological and immunohistochemical variations of mucin glycoproteins. Recently, a consensus nomenclature and criteria were histologically defined for classifying these variants of IPMNs into gastric, intestinal, pancreatobiliary, and oncocytic types. The purpose of this study was to determine associations between the histological types and clinicopathological features in patients with IPMN.

Transplantation of isolated hepatocytes has been proposed to compensate for essential functions lacking in liver failure or for genetic defects that alter a specific liver metabolic pathway. Hepatocyte utilization for these purposes would be facilitated with a reliable, reproducible, and effective method of long-term hepatocyte storage. We have recently developed a simple new system for cryopreservation of hepatocytes that encapsulates alginate microspheres and maintains liver-specific function. The aim of this study was to elucidate the transport and drug-metabolizing enzyme activities of cryopreserved microencapsulated hepatocytes stored for a long time. Morphological examinations showed there is no apparent injury of the hepatocytes during cryopreservation processes. A drug-metabolizing enzyme (testosterone 6β-hydroxylase, a specific probe for CYP3A2) and drug transport activities [salicylate, allopurinol, and prostaglandin E2(PGE2), typical substrates of rOat2] in cryopreserved microencapsulated hepatocytes were maintained up to 120 days. Our results thus demonstrate for the first time that cryopreservation of primary rat hepatocytes by the encapsulation technique allows long-term retention of drug metabolism and drug transport activities.

Encapsulated hepatocyte transplantation is a promising approach to cell transplantation without immunosuppression as an alternative to whole organ liver transplantation. However, the shortage of donor cells for hepatocyte transplantation has not been resolved, and at this critical point, it seems necessary to establish a method of hepatocyte cryopreservation to allow clinical application of hepatocyte transplantation and the development of a bioartificial liver system in the near future. In this study we demonstrated that cryopreserved microencapsulated rat and human hepatocytes can retain their hepatic function and that cryopreserved microencapsulated human hepatocytes transplanted into rat spleen remain viable without immunosuppression. Rat and human hepatocytes were isolated by a collagenase digestion method, and they were microencapsulated with poly-L-lysine. The microencapsulated rat hepatocytes were transferred to culture medium (DMEM containing 10% FBS and 10% DMSO) and immediately frozen in liquid nitrogen. A warm water bath (37°C) was used to thaw the microencapsulated hepatocytes. Hepatic function, drug metabolism, and cell morphology were assessed after 90 days of cryopreservation. After 1 week of cryopreservation, microencapsulated hepatocytes were cultured for up to 2 weeks to assess their hepatic function and morphology. The morphology of human hepatocytes was assessed after 30 days of cryopreservation. Cryopreserved human hepatocytes were transplanted into rat spleen to assess their morphology. Cryopreserved microencapsulated hepatocytes retained their viability and were strongly positive for expression of albumin, OAT2, CYP3A2, and CYP3A9. Two weeks after cultivation, the cryopreserved microencapsulated rat hepatocytes had retained their hepatic function (urea synthesis). Cryopreserved microencapsulated human hepatocytes also mainly survived and retained their hepatic function for at least 30 days after cryopreservation. Moreover, entrapped cryopreserved human hepatocytes also survived and expressed albumin in rat spleen after transplantation. We demonstrated a novel method of long-term cryopreservation of rat and human hepatocytes by using an encapsulation technique, with retention of biological activity and excellent survival of the cryopreserved microencapsulated human hepatocytes transplanted into rat spleen. We believe that this novel approach to hepatocytes cryopreservation provides a new direction in encapsulated cell therapy with the goal of clinical application in the near future.

Pancreatic islet transplantation is limited by shortage of donor organs. Although β-cell lines could be used, their secretion of insulin is characteristically glucose independent and immunoisolation is required. Here we show that intrasplenic transplantation of encapsulated glucose-responsive mouse insulinoma cells reversed streptozotocin (STZ)-induced diabetes in rats. MIN-6 cells derived from a transgenic mouse expressing SV 40 large T antigen in pancreatic β-cells were transfected with minigene encoding for human glucagon-like-peptide-1 under the control of rat insulin promoter. The cells were encapsulated in alginate/poly-L-lysine and used for cell transplantation in STZ-diabetic rats. Rats with nonfasting blood glucose (n-FBG) greater than 350 mg/dl were used. In group I rats (n = 6) 20 million encapsulated cells were injected into the spleen. Group II rats (n = 6) received empty capsules. n-FBG was measured biweekly. After 4 and 8 weeks, an intraperitoneal glucose tolerance test (IPGTT) was performed in group I; normal rats served as controls. Plasma insulin level was measured every other week (RIA). After 8 weeks, spleens were removed 1 day before sacrifice. In rats transplanted with cells the n-FBG was 100—150 mg/dl until the end of the study. After splenectomy, all cell recipients became diabetic (glucose 400 ± 20 mg/dl). Transplanted rats showed increase in body weight and insulin production (3.3 ± 1.0 ng/ml versus 0.92 ± 0.3 ng/ml; p < 0.01) and had normal IPGTT. Spleens contained capsules with insulin-positive cells. Overall, data from this work indicate that intrasplenic transplantation of xenogeneic encapsulated insulin-producing cells without immunosuppression reversed diabetes in rats. Excellent survival and function of the transplanted cells was due to the fact that the cells were separated from the bloodstream by the immunoisolatory membrane only and insulin was delivered directly to the liver (i.e., in a physiological manner).