bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Large-Scale Isolation of Breeder Porcine Islets: Possibility of Harvesting from Nonheart-Beating Donor
Authors: Miyamoto Masaaki , Inoue Kazutomo , Gu Yuanjun , Tun Thein , Cui Wanxing , Fujiwara Ikuya , Ohyanagi Harumasa , Hayashi Hiroyuki , Yamazaki Tooru , Setoyama Hiroshi , Kawakami Yoshiyuki , Ida Jun , Kogire Masafumi , Imamura Masayuki , Iwata Hiroo , Ikada Yoshito
Published: June 2017

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.
Multiplicity of Glucocorticoid Action in Inhibiting Allograft Rejection
Authors: Almawi Wassim Y. , Hess David A. , Rieder Michael J.
Published: June 2017

Glucocorticoids (GCs) are used as immunosuppressive and antiinflammatory agents in organ transplantation and in treating autoimmune diseases and inflammatory disorders. GCs were shown to exert their antiproliferative effects directly through blockade of certain elements of an early membrane-associated signal transduction pathway, modulation of the expression of select adhesion molecules, and by suppression of cytokine synthesis and action. GCs may act indirectly by inducing lipocortin synthesis, which in turn, inhibits arachidonic acid release from membrane-bound stores, and also by inducing transforming growth factor (TGF)-β expression that subsequently blocks cytokine synthesis and T cell activation. Furthermore, by preferentially inhibiting the production of Th1 cytokines, GCs may enhance Th2 cell activity and, hence, precipitate a long-lasting state of tolerance through a preferential promotion of a Th2 cytokine-secreting profile. In exerting their antiproliferative effects, GCs influence both transcriptional and posttranscriptional events by binding their cytosolic receptor (GR), which subsequently binds the promoter region of cytokine genes on select DNA sites compatible with the GCs responsible elements (GRE) motif. In addition to direct DNA binding, GCs may also directly bind to, and hence antagonize, nuclear factors required for efficient gene expression, thereby markedly reducing transcriptional rate. The pleiotrophy of the GCs action, coupled with the diverse experimental conditions employed in assessing the GCs effects, indicate that GCs may utilize more than one mechanism in inhibiting T cell activation, and warrant careful scrutiny in assigning a mechanism by which GCs exert their antiproliferative effects. © 1998 Elsevier Science Inc.
Effects of Surgical Anaesthesia on the Viability of Nigral Grafts in the Rat Striatum
Authors: Dunnett S.B. , Torres E.M. , Richards H. , Barker R.A.
Published: June 2017

Only a small proportion of dopamine neurons in nigral grafts typically survive transplantation into the adult striatum. Since many anaesthetics reduce blood flow and disturb a variety of brain metabolites, surgical anaesthesia may be one of the factors that compromise graft survival. Conversely, the lowered core body temperature induced by some anaesthetics might promote the survival of grafted cells by slowing their metabolism. In an initial screen, the widely-used surgical anaesthetic, equithesin, was found to reduce core temperature, mean arterial blood pressure, and to increase the partial pressure of oxygen in arterial blood without producing any significant alteration in arterial pH or the partial pressure of carbon dioxide. In the main experiment, rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal bundle received dopamine-rich embryonic nigral grafts injected into the deafferented neostriatum via previously implanted guide cannulae, which allowed comparison to be made of graft survival after transplantation into awake and in re-anaesthetised animals. There were no significant differences between groups in either the functional effects of the grafts to compensate amphetamine-induced rotation, or in the survival and growth of the grafts as measured in post mortem histology. We therefore conclude that anaesthesia per se is not a major contributory factor in the relatively poor survival of dopamine neurons following transplantation into the rat striatum.
Long-Term Amerlioration of Bilirubin Glucuronidation Defect in Gunn Rats by Transplanting Genetically Modified Immortalized Autologous Hepatocytes
Authors: Tada Kouji , Roy-Chowdhury Namita , Prasad Vinayaka , Kim Byung-Ho , Manchikalapudi P. , Fox Ira J. , Van Duijvendijk Peter , Bosma Piter J. , Roy-Chowdhury Jayanta
Published: June 2017

Ex vivo gene therapy, in which hepatocytes are harvested from mutants, retrovirally transduced with a normal gene and transplanted back into the donor, has been used for correction of inherited metabolic defects of liver. Major drawbacks of this method include limited availability of autologous hepatocytes, inefficient retroviral transduction of primary hepatocytes, and the limited number of hepatocytes that can be transplanted safely. To obviate these problems, we transduced primary hepatocytes derived from inbred bilirubin–UDP–glucuronosyl–transferase (BUGT)-deficient Gunn rats by infection with a recombinant retrovirus expressing temperature-sensitive mutant SV40 large T antigen (tsT). The immortalized cells were then transduced with a second recombinant retrovirus expressing human B-UGT, and a clone expressing high levels of the enzyme was expanded by culturing at permissive temperature (33°C). At 37°C, tsT antigen was degraded and the cells expressed UGT activity toward bilirubin at a level approximately twice that present in normal rat liver homogenates. For seeding the cells into the liver bed, 1 × 107 cells were injected into the spleens of syngeneic Gunn rats five times at 10-day intervals. Excretion of bilirubin glucuronides in bile was demonstrated by HPLC analysis and serum bilirubin levels were reduced by 27 to 52% in 40 days after the first transplantation and remained so throughout the duration of the study (120 days). None of the transplanted Gunn rats or SCID mice transplanted with the immortalized cells developed tumors. © 1998 Elsevier Science Inc.
Purification of Adrenal Chromaffin Cells Increases Antinociceptive Efficacy of Xenotransplants without Immunosuppression
Authors: Michalewicz P. , Laurito C. E. , Pappas G. D. , Lu Y. , Yeomans D. C.
Published: June 2017

We have found that immunosuppression is necessary for the survival of xenogeneic adrenal medullary transplants. Because chromaffin cells are essentially nonimmunogenic, it is likely that the highly immunogenic “passenger” cells in the transplant preparation bring about rejection. This article describes a procedure that produces an essentially pure preparation of chromaffin cells for transplantation. Bovine adrenal medullary cells were isolated and differentially plated, resulting in a semipurified preparation of chromaffin cells. Ferromagnetic beads were added to the cell suspension, some of which were phagocytized by endothelial cells, which allowed their removal by exposure to a magnet. The remaining cells were then exposed to ferromagnetic beads coated with isolectin B4 from Griffonia simplicifolia and once again to a magnetic field. The “semipurified” preparation contained approximately 90% chromaffin cells, whereas the “highly purified” preparation was > 99.5% chromaffin cells as determined immunohistochemically. The immunogenicity of the two cell preparations was assessed in vitro by determining their capacity to evoke lymphocyte proliferation. Rat spleen lymphocytes were mixed with either a highly purified or semipurified population of bovine chromaffin cells. The results of this assay demonstrated that the highly purified preparation was a much weaker stimulant of lymphocyte proliferation than was the semipurified preparation and may demonstrate better graft survival in vivo. Transplantation via intrathecal catheter of either 80,000 or 250,000 cells from the highly or partially purified preparations onto the lumbar spinal cord of nonimmunosuppressed and nonnicotine-stimulated rats produced a cell number-dependent antinociception for both Aδ and C fiber-mediated thermonociception at 6 days after transplantation. After 6 days and up to 28 days, only the “highly purified” preparation showed antinociception. These results suggest that nearly complete purification of bovine chromaffin cells minimizes immunorejection of xenogeneic transplants of these cells.
Biocompatibility of Poly (DL-Lactide-co-Glycolide) Microspheres Implanted into the Brain
Authors: Emerich Dwaine F. , Tracy Mark A. , Ward Kevin L. , Figueiredo Maria , Qian Rulin , Henschel Carroll , Bartus Raymond T.
Published: June 2017

The delivery of therapeutic molecules to the brain has been limited in part due to the presence of the blood–brain barrier. One potential solution is the implantation of biodegradable polymers with sustained release of drugs. Poly (DL-lactide-co-glycolide) (PLG) is a bioerodible polymer with a long and successful history of use as a suture material. More recently, PLG has been investigated for localized and sustained delivery of molecules into both peripheral sites and the brain. Despite its well-defined safety profile for parenteral applications, little information exists concerning the safety of PLG when implanted into the brain. To further characterize the biocompatibility of PLG in the brain, we examined the gliotic response following implants of PLG into the brains of rats. As a control, each animal received an injection of the suspension medium into the contralateral hemisphere. Following implantation, PLG was well tolerated. GFAP-positive astrocytes were observed throughout the cerebral cortex and striatum on both the implanted and control sides, with the reaction being greatest within the heavily myelinated fiber tracts of the corpus callosum. Quantitative analyses revealed that this reaction occurred within 1 h postsurgery, reached its peak at 1 week following surgery, and then decreased markedly by 1 month postsurgery. A minimal gliotic reaction was still present 1 year postsurgery but was localized to the needle tract. No differences in GFAP reactivity were seen between the polymer-implanted and control sides at any time point. Histological analysis determined that the majority of the PLG disappeared between 1 and 4 weeks. A set of parallel studies in which PLG samples were retrieved from the brain at various time points corroborated these findings and determined that the majority of PLG degraded within 2 weeks following implantation. Together, these results demonstrate that PLG is well tolerated following implantation into the CNS and that the astrocytic response to PLG is largely a consequence of the mechanical trauma that occurs during surgery. The biocompatibility of PLG implanted into the CNS provides further support for its use in a wide range of new therapeutic applications for sustained and localized drug delivery to the brain.
Osmotic Tolerance Limits of Canine Pancreatic Islets
Authors: Zieger Michael A. J. , Woods Erik J. , Lakey Jonathan R. T. , Liu Jun , Critser John K.
Published: June 2017

Future improvements in the recovery and function of pancreatic islets following cryopreservation will require a more precise quantification of the stresses that occur at each stage of the cryopreservation protocol. Changes in solution osmolality during the addition and dilution of cryoprotectants and during freezing and thawing induce changes in islet volume that may exceed tolerable limits. The aim of this study was to determine the range of solution osmolalities that results in significant changes in islet function. Islets were isolated from canine pancreases by collagenase digestion and Euro-Ficoll purification. Following 12-h culture at 37°C, islets were counted and dispensed into multiwell plate inserts. Islet function was assessed in each well immediately before and 24 h following a 10-min osmotic challenge with hypo- or hyperosmotic solutions of PBS (0, 75, 150, 300, 600, 1200, or 2300 mOsm/kg) at 22°C. Canine islets reached their osmotic equilibrium within 10 min. Duplicate wells were used for each osmolality treatment for each of six donors (n = 12). No significant differences in basal or glucose-stimulated insulin secretion were found between wells prior to the osmotic challenge (3.35 ± 0.45 and 20.98 ± 3.36 μIU/IE/h, respectively). Following the osmotic challenge and 24-h in vitro tissue culture, a significant increase in basal secretion was observed for islets exposed to 0 and 75 mOsm/kg solutions and a significant decrease for islets exposed to 2300 mOsm/kg solution. Islets exposed to 0 and 2300 mOsm/kg solutions showed significant decreases in the stimulated insulin secretion when compared to controls. Solution osmolalities of 150–1200 mOsm/kg appear to be tolerated by canine islets with no significant deviations in insulin secretion. The corresponding tolerable volume range was 152.6 ± 6.8% to 60 ± 5.1% of the isotonic islet volume. The minimum critical volume was used in a theoretical analysis of the islet volumes that would result from equilibrium freezing in dimethyl sulfoxide (DMSO). The calculations show that 1.5 mol/l DMSO is sufficient to prevent damage to islets due to excessive shrinkage. Further refinement of cryoprotectant addition and dilution protocols, and cooling and warming protocols for canine islets, are now possible.
In Vitro and in Vivo Performance of Porcine Islets Encapsulated in Interfacially Photopolymerized Poly(Ethylene Glycol) Diacrylate Membranes
Authors: Cruise Gregory M. , Hegre Orion D. , Lamberti Francis V. , Hager Steven R. , Hill Ron , Scharp David S. , Hubbell Jeffrey A.
Published: June 2017

The usefulness of interfacial photopolymerization of poly(ethylene glycol) (PEG) diacrylate at a variety of concentrations and molecular weights to form hydrogel membranes for encapsulating porcine islets of Langerhans was investigated. The results from this study show in vitro and in vivo function of PEG-encapsulated porcine islets and the ability of PEG membranes to prevent immune rejection in a discordant xenograft model. Encapsulated islets demonstrated an average viability of 85% during the first week after encapsulation, slightly but significantly lower than unencapsulated controls. Encapsulated porcine islets were shown to be glucose responsive using static glucose stimulation and perifusion assays. Higher rates of insulin release were observed for porcine islets encapsulated in lower concentrations of PEG diacrylate (10–13%), not significantly reduced relative to unencapsulated controls, than were observed in islets encapsulated in higher concentrations (25%) of PEG diacrylate. Perifusion results showed biphasic insulin release from encapsulated islets in response to glucose stimulation. Streptozotocin-induced diabetic athymic mice maintained normoglycemia for up to 110 days after the implantation of 5,000–8,000 encapsulated porcine islet equivalents into the peritoneal cavity. Normoglycemia was also confirmed in these animals using glucose tolerance tests. PEG diacrylate-encapsulated porcine islets were shown to be viable and contain insulin after 30 days in the peritoneal cavity of Sprague-Dawley rats, a discordant xenograft model. From these studies, we conclude that PEG diacrylate encapsulation of porcine islets by interfacial photopolymerization shows promise for use as a method of xenoprotection toward a bioartifical endocrine pancreas.
The Rescue Effect of 15-Deoxyspergualin on Intraperitoneal Microencapsulated Xenoislets
Authors: Hsu Brend Ray-Sea , Chang Fu-Hsiung , Juang Jyuhn-Huarng , Huang Yu-Yao , Fu Shin-Huei
Published: June 2017

Because the development of surface neogrowth composed mainly of macrophages and fibroblasts precedes the recurrence of hyperglycemia in treated diabetic animals, the pericapsular macrophages may adversely affect the graft function of IP alginate-poly-L-lysine-alginate (A-P-A) microencapsulated islets. In order to clarify the role of pericapsular macrophages on late islet xenograft dysfunction, we investigated whether 15-deoxyspergualin (15-DSG), a macrophage inhibitor, has a rescue effect on the recurrent hyperglycemia in streptozotocin-induced diabetic mice that had been treated with IP transplantation of A-P-A microencapsulated rat islets. The mean duration of normoglycemia (whole blood glucose level below 8.3 mmol/l) in streptozotocin-induced diabetic mice treated with implantation of about 2200–2400 of A-P-A microencapsulated rat islets was 75 days. When the blood glucose levels were higher than 11.1 mmol/l for two consecutive determinations, 15-DSG at a dose of 0.625 mg/kg body weight or isotonic sodium chloride solution (control group) was given daily SC. The blood glucose levels decreased significantly from 13.9 ± 0.5 mmol/l to 11.0 ± 1.3 mmol/l (n = 18, p < 0.05) at the fourth day and to 7.6 ± 1.0 mmol/l (n = 18) at the 14th day of 15-DSG administration. That was not significantly different from the mean glycemic level during the normoglycemic period (7.6 ± 1.0 vs. 7.0 ±1.7 mmol/l, n = 18, p = NS). Isotonic sodium chloride solution injections did not reduce glycemic levels of mice in the control group. As another control, 10 streptozotocin-induced diabetic mice were given the same daily doses of 15-DSG for 14 days. 15-DSG did not decrease the blood glucose levels of diabetic mice in the control group. We further studied the effect of 15-DSG on the expression of interleukin-1β (IL-1β) in peritoneal exudate mononuclear cells (PEMCs) using reverse transcription-polymerase chain reaction. It was found that the mRNA of IL-1β was undetectable in PEMCs of 15-DSG-treated diabetic mice even after those cells were stimulated by lipopolysaccharides in vitro. Administration of 15-DSG at a daily dose of 0.625 mg/kg body weight from the 22nd to the 28th day after transplantation and 7 consecutive days every 3 weeks thereafter did not prolong graft survival of IP microencapsulated rat islets. Our data suggest that 15-DSG has a rescue effect when A-P-A microencapsulated islets have induced cellular overgrowth that threatens the survival of the graft. It is possible that the surface overgrowth composed of macrophages is involved in the pathophysiology of late failure of A-P-A microencapsulated xenogeneic islets.
Design Engineering of a Bioartificial Renal Tubule Cell Therapy Device
Authors: Nikolovski Janeta , Gulari Erdogan , Humes H. David
Published: June 2017

The use of a bioartificial renal tubule device composed of renal proximal tubule cells grown within a hollow fiber cartridge is a first step in engineering a bioartificial kidney to provide more complete replacement therapy of renal function than is available today. In this study, the feasibility of two designs for a tubule device were investigated: one with cells grown on microcarrier beads densely packed within the extracapillary space of a hollow fiber cartridge, and the other with cells grown as a confluent monolayer within the hollow fibers themselves. First, the oxygen requirements of porcine renal proximal tubule cells were determined, both attached to microcarriers and in suspension and compared to that of proximal tubule segments. The basal rate of cell respiration was found to be 2.29 ± 0.53 nmol O2/106 cells/min for our cultured proximal tubule cells in suspension and no significant difference was seen with attached cells. Proximal tubule segments displayed significantly higher respiratory rates. Cells were also found to be responsive in the presence of mitochondrial inhibitors or uncouplers, and their respiratory rates remained constant, despite multiple passaging. The resultant cell oxygen consumption parameter was used in models describing oxygen concentration profiles within the two device configurations. From these models, it was found that cells within our proposed device designs could theoretically be sustained and remain viable, with respect to oxygen limitations. Finally, flow visualization studies were performed to assess fluid flow distribution and determine optimal device configuration and geometry to decrease areas of low or stagnant flow.
Forskolin-Stimulated Adenylylcyclase Activity: A Marker to Assess Islet Cell Viability Following Cold Storage in Different Solutions and to Predict Islet Cell Function following Transplantation
Authors: Kanazawa Shigeo , Tsunoda Tsukasa , Murakami Masakazu , Iwamoto Sueharu , Kimoto Masatoshi , Onuma Eishi , Majima Toshimitsu , Yamamoto Yasuhisa
Published: June 2017

For clinical islet cell transplantation, short-term storage of islet cells is likely to be necessary, and it is imperative that the islet cells be kept as viable as possible during the period. However, there are little data on which preservative solutions are most suitable for the storage of islet cells after isolations or before transplantation. To estimate islet cell viability and transplantation success rate in the present study, adenylylcyclase activity was measured with a rapid new fluorometric assay in rat islet cells prior to transplantation, because cAMP plays an essential role in determining islet β-cell viability and responsiveness to various hormonal stimuli. Adenylylcyclase activity was measured in islet cells stored for different periods of time (0, 3, 16, 24, 48, 96 h) and in different preservative solutions. Approximately 1,000 islet cells from each preservation group using University of Wisconsin (UW) solution were transplanted to streptozotocin-induced diabetes mellitus (DM) rats. Transplant success was evaluated by measuring blood glucose levels. Preoperative adenylylcyclase activity was compared with posttransplant islet cell function. The adenylylcyclase activity of UW solution was significantly higher than that of Euro-Collins solution and lactate-Ringer's solution through the different preservation time periods. Preoperative adenylylcyclase activity correlated well with posttransplant islet cell function in a rat model of DM. We conclude that adenylylcyclase activity can be used as a marker to assess islet cell viability as well as differences in preservation media and may predict islet cell transplant success.
Differentiation and Angiogenesis of Central Nervous System Stem Cells Implanted with Mesenchyme into Ischemic Rat Brain
Authors: Fukunaga Atsushi , Uchida Koichi , Hara Koichi , Kuroshima Yoshiaki , Kawase Takeshi
Published: June 2017

After cerebral infarction, necrosis in neural tissues is not usually repaired or reconstructed by the injured brain. We therefore examined the effects on postinfarction repair of implanting central nervous system (CNS) stem cells together with mesenchyme, because CNS stem cells can be expected to adapt and survive in the adult brain. Cerebral infarction was induced by the Koizumi-Longa method, using the adult male spontaneous hypertensive rat model. Reperfusion was performed an hour after middle cerebral artery occlusion. The rat mesencephalic neural plate at the early somite stage (embryonic day 10.5) together with the adjacent ventral mesenchymal tissues was dissected out under the microscope and immediately implanted into the ischemic rat striatum. One month later, the cognitive function was evaluated by the Morris water maze method. Histologic and immunohistochemical examinations of the graft were made with hematoxylin-eosin (H&E), neurofilament-200, and tyrosine hydroxylase (TH) stains. In the water maze study, mean latency times required to reach an escape platform in the implanted animals with surviving grafts were found to be shorter than in those without grafts, but longer than in normal animals. In the spatial probe trial, the number of animals seen to cross the area in the pool where the platform had been located was greater in the implanted rats with surviving grafts than in other groups. Multiple vascularization in the grafted area was observed histologically in H&E-stained tissues, and neurofilament-200-positive cells were recognized in the graft. TH staining revealed within the graft many immunoreactive neuron-like cell bodies with long dendrites. It was suggested that grafted CNS stem cells with mesenchyme may survive and differentiate into mature CNS tissue within the adult ischemic rat brain, constructing vessels in and around the grafts, and may therefore have the potential to be effective in the recovery of the cognitive function of the rat model.
Fabrication of Compliant Hybrid Grafts Supported with Elastomeric Meshes
Authors: Kobashi Teisei , Matsuda Takehisa
Published: June 2017

We devised tubular hybrid medial tissues with mechanical properties similar to those of native arteries, which were composed of bovine smooth muscle cells (SMCs) and type I collagen with minimal reinforcement with knitted fabric meshes made of synthetic elastomers. Three hybrid medial tissue models that incorporated segmented polyester (mesh A) or polyurethane-nylon (mesh B) meshes were designed: the inner, sandwich, and wrapping models. Hybrid medial tissues were prepared by pouring a cold mixed solution of SMCs and collagen into a tubular glass mold consisting of an inner mandrel and an outer sheath and subsequent thermal gelation, followed by further culture for 7 days. For the inner model, the mandrel was wrapped with a mesh. For the sandwich model, a cylindrically shaped mesh was incorporated into a space between the mandrel and the sheath. The wrapping model was prepared by wrapping a 7-day-incubated nonmesh gel with a mesh. The inner diameter was 3 mm, irrespective of the model, and the length was 2.5–4.0 cm, depending on the model. The intraluminal pressure–external diameter relationship showed that nonmesh and inner models had a very low burst strength below 50 mmHg, while the sandwich model ruptured at around 110–120 mmHg; no rupturing below 240 mmHg was observed for the wrapping model, regardless of the type of mesh used. Compliance values of wrapping and sandwich models were close to those of native arteries. Pressure-dependent distensibility characteristics similar to native arteries were observed for a mesh A wrapping model, whereas a mesh B wrapping model expanded almost linearly as intraluminal pressure increased, which appeared to be due to elasticity of the incorporated mesh. Thus, design criteria for hybrid vascular grafts with appropriate biomechanical matching with host arteries were established. Such hybrid grafts may be mechanically adapted in an arterial system.
High Variability in Rabbit Bone Marrow-Derived Mesenchymal Cell Preparations
Authors: Solchaga Luis A. , Johnstone Brian , Yoo Jung U. , Goldberg Victor M. , Caplan Arnold I.
Published: June 2017

The rabbit has been extensively used for preclinical models, especially in orthopedic applications. One of the more troubling features of this model is the high interindividual variability that is encountered and that requires a careful experimental design with sufficient sample size to make judgments valid. We have processed 241 individual preparations of rabbit bone marrow-derived mesenchymal progenitor cells (MPCs) over the last 3 years and have kept detailed records of the performance of these cells in various assays. This communication details the lack of correlation between the analyzed parameters. Bone marrow was harvested from 4-month-old rabbits; the cells were centrifuged, resuspended, and cultured. When cells reached 80% of confluence, they were removed from the plates with trypsin and assayed for their osteo- and chondrogenic potential. The average yield of the 241 individual MPC preparations exhibited a coefficient of variation of 77. An in vivo implantation assay with porous calcium phosphate ceramic cubes exhibited scores with a coefficient of variation of 65. Lastly, an in vitro assay of alkaline phosphatase enzyme activity exhibited the most variability with a coefficient of variation of 132. All of the cell preparations tested in an in vitro aggregate culture assay underwent chondrogenic differentiation. No relationships between any of these parameters were found. The variability of the results within the different assays is interpreted to be the result of the heterogeneity of the preparations. The lack of correlation between the parameters studied shows the importance of the conditions intrinsic to the different assays. These results serve to emphasize that any experimental design involving rabbit progenitor cells must include a sufficiently large sample size to allow statistically significant and rigorous conclusions.
Freezing Characteristics of Genetically Modified Lymphocytes for the Treatment of MPS II
Authors: Hubel A. , Darr T. B. , Norman J. A.
Published: June 2017

The freezing characteristics of genetically modified lymphocytes obtained from a donor with mucopolysaccharidosis type II (MPS II) were determined using cryomicroscopy and controlled rate freezing studies to determine postthaw viability. The cells from a donor with MPS II used in this investigation were cultured and transduced with a retroviral vector for the iduronate-2-sulfatase (IDS) enzyme for clinical studies for human gene therapy. The water transport and intracellular ice formation (IIF) characteristics of the cells were determined after completion of the culture and transduction protocol. The water transport parameters, Lpg and Elp, for the cultured and transduced cells were determined to be 4.4 ± 1.3 × 10–14 m3/Ns and 173 ± 25 kJ/mol, respectively. The IIF nucleation parameters, κ and Ω, were 5.5 × 1010 K5 and 3.5 × 1011 (1/m2 s), respectively. The postthaw viability of the genetically modified cells was less than the viability of the freshly isolated cells from the same donor. The postthaw viability of the cultured and transduced cells from a donor with MPS II was also less than that observed with cells from a normal donor that were frozen and thawed under the same conditions. These studies are essential in understanding the biophysical changes resulting from the ex vivo culture of cells and the manner in which these changes influence the ability of the cells to be cryopreserved.
Differentiation and Expansion of Beta Cell Mass in Porcine Neonatal Pancreatic Cell Clusters Transplanted into Nude Mice
Authors: Yoon Kun-Ho , Quickel Robert R. , Tatarkiewicz Krystyna , Ulrich Thomas R. , Hollister-Lock Jennifer , Trivedi Nitin , Bonner-Weir Susan , Weir Gordon C.
Published: June 2017

Neonatal porcine pancreas has considerable capacity for growth and differentiation, making it an attractive potential source of islet tissue for xenotransplantation. Pancreases from 1–3-day-old newborn pigs were digested with collagenase and cultured for 8 days. The resulting cellular aggregates are called porcine neonatal pancreatic cell clusters (NPCCs). The mean yield of NPCCs from a newborn pig was 28,200 ± 1700 islet equivalents. Cytokeratin 7 (CK7) was used as a marker for the immunostaining of pancreatic duct cells. In neonatal pancreas, 18% of the insulin-positive cells co-stained for CK7, thus being protodifferentiated. NPCCs also contained protodifferentiated cells; insulin/PP and insulin/somatostatin co-stained cells were more common than insulin/glucagon cells. Between 1 and 8 days of culture, the DNA content of the NPCCs fell to 16% and the insulin content to 33% of the starting value, mainly due to the preferential loss of exocrine cells. Transplantation of 2000 or 4000 NPCCs into diabetic nude mice typically normalized glucose values in 10–20 weeks. Mice with successful grafts had lower fasting blood glucose levels than normal mice and accelerated glucose clearance after an IP glucose load. The starting NPCCs consisted of 17% insulin-staining cells, but the grafts of mice with reversed diabetes consisted of 94% beta cells, with some co-stained for CK7, indicating that the grafts still contained immature cells. The mass of insulin-producing cells rose from 0.22 ± 0.08 mg 1 week after transplantation to 4.34 ± 0.27 mg in mice sacrificed at 27–35 weeks. In summary, NPCCs contain mostly islet precursor cells, which when transplanted into nude mice undergo striking differentiation and beta cell expansion.
Secretion from Islets and Single Islet Cells following Cryopreservation
Authors: Lakey Jonathan R. T. , Aspinwall Craig A. , Cavanagh Thomas J. , Kennedy Robert T.
Published: June 2017

The ability to cryopreserve pancreatic islets has allowed the development of low-temperature banks that permit pooling of islets from multiple donors and allows time for sterility and viability testing. However, previous studies have shown that during cryopreservation and thawing there is a loss of islet mass and a reduction in islet function. The aim of this study was to measure and compare insulin secretion from cultured nonfrozen and frozen–thawed canine islets and β-cells. Canine islets were isolated from mongrel dogs using intraductal collagenase distention, mechanical dissociation, and EuroFicoll purification. One group of purified islets was cultured overnight before dissociation into single cells and subsequent analysis. Remaining islets were cultured overnight (22°C) and then cryopreserved in 2 M dimethyl sulfoxide (DMSO) solution using a slow stepwise addition protocol with slow cooling to −40°C before storage in liquid nitrogen (−196°C). Frozen islets were rapidly thawed (200°C/min) and the DMSO removed using a sucrose dilution. From a series of seven consecutive canine islet isolations, islet recovery following postcryopreservation tissue culture was 81.5 ± 4.8% compared to precryopreservation counts. In vitro islet function was equivalent between cultured nonfrozen and frozen–thawed islets with a calculated stimulation index of 10.4 ± 1.5 (mean ± SEM) for the frozen–thawed islets, compared with 12.4 ± 1.2 for the cultured nonfrozen controls (p = ns, n = 7 paired experiments). Amperometric detection of secretion from single β-cells in vitro has the sensitivity and temporal resolution to detect single exocytotic events and allows secretion to be monitored from single β-cells in real time. Secretion from single β-cells elicited by chemical stimulation was detected using a carbon fiber microelectrode. The frequency of exocytosis events was equivalent between the cultured nonfrozen and frozen–thawed β-cells with an average of 7.0 ± 1.32 events per stimulation for the cultured nonfrozen group compared with 6.0 ± 1.45 events from the frozen then thawed preparations (minimum of 10 cells per run per paired experiment, p = ns) following stimulation with tolbutamide. The average amount of insulin released per individual exocytosis event was equivalent for the cultured nonfrozen and frozen–thawed islets. In addition, β-cells responded to both tolbutamide and muscarinic stimulation following cryopreservation. It was determined that β-cells recovered following cryopreservation are capable of secreting insulin at levels and frequencies comparable to those of cultured nonfrozen islet preparations.
MicroRNA-195 inhibits the proliferation and invasion of pancreatic cancer cells by targeting the fatty acid synthase/Wnt signaling pathway
Authors: Xu Zhichao , Li Chunli , Qu Hui , Li Huiling , Gu Qiaoyan , Xu Jing
Published: June 2017

Emerging evidence suggests that microRNAs are critical regulators of cancer development and progression. MicroRNA-195 has been reported as a cancer-related microRNA in many human cancers. However, the role of microRNA-195 in pancreatic cancer remains largely unknown. Here, we show that microRNA-195 is downregulated in pancreatic cancer tissues and cell line. Also, we show that overexpression of microRNA-195 inhibits the proliferation and invasion of pancreatic cancer cells, whereas suppression of microRNA-195 promotes proliferation and invasion. We show that microRNA-195 directly targets the fatty acid synthase enzyme and negatively regulates the expression of fatty acid synthase. Also, we show that fatty acid synthase expression is inversely correlated with microRNA-195 expression in pancreatic cancer tissues. Moreover, our results show that microRNA-195 inhibits Wnt signaling in pancreatic cancer cells. By restoring fatty acid synthase expression, we were able to reverse the antitumor effects of microRNA-195 in pancreatic cancer cells. Taken together, our findings show that microRNA-195 inhibits pancreatic cancer cell proliferation and invasion by regulating the fatty acid synthase/Wnt signaling pathway, suggesting a tumor suppressive role for microRNA-195 in the development and progression of pancreatic cancer. Thus, inhibiting fatty acid synthase by microRNA-195 may serve as a novel therapeutic approach for the treatment of pancreatic cancer.
From internet swear words to stadium violence in football (soccer) games – An Israeli case study
Authors: Ben Shalom Uzi , Dvir Amit , Levy Moshe , Zwilling Moti , Orkibi Eithan , Gabay Nadav , Pele Ofir
Published: June 2017

This study explored the relevancy of internet discourse among football fans and real-life stadium violence. Our hypothesis implies that there are positive correlations between violent utterances in fans’ social networks prior to games and football stadium violence. The study sample included 6 football clubs who participated in the Israeli Premier League in the 2015–2016 season. The traffic in the social networks was automatically collected into the MySQL database. The content of the traffic includes various forms of discursive interactions within social networks susceptible of predicting, provoking or expressing social tension, aggression or violent behavior. We focused on three discursive functions which reflect a dynamic of discursive construction of tension: exclamation; incitement; and verbal aggression. The results indicate a build-up of tension 3 days before the game and such build-up is correlated with stadium violence of both fans and players. The correlation of content and timing of traffic was also found when controlling the level of violence of the football club. Violent traffic was also correlated with the results of the previous game. The theoretical and practical consequences of these results are discussed.
Management of Oral Anticoagulation Therapy After Gastrointestinal Bleeding: Whether to, When to, and How to Restart an Anticoagulation Therapy
Authors: Kido Kazuhiko , Scalese Michael J.
Published: June 2017

Objective: To evaluate current clinical evidence for management of oral anticoagulation therapy after gastrointestinal bleeding (GIB) with an emphasis on whether to, when to, and how to resume an anticoagulation therapy. Data Sources: Relevant articles from MEDLINE, Cochrane Library, and EMBASE databases were identified from 1946 through May 20, 2017, using the keywords: gastrointestinal hemorrhage or gastrointestinal bleeding and antithrombotic therapy or anticoagulation therapy or warfarin or dabigatran or rivaroxaban or apixaban or edoxaban.Study Selection and Data Extraction: All English-language studies assessing management of oral anticoagulation therapy after GIB were evaluated. Data Synthesis: A total of 9 studies were identified. Four retrospective cohort studies showed that resuming anticoagulation therapy was associated with significantly lower rate of thromboembolism (TE) in the general population. Meta-analyses and prospective cohort studies also supported this finding. Two retrospective cohort studies indicated an increase in GIB when anticoagulation reinitiation occurred in less than 7 days without a decrease in TE. Resuming therapy between 7 and 15 days did not demonstrate a significant increase in GIB or TE. A large retrospective study showed that apixaban was associated with the significantly lowest risk of GIB compared with both rivaroxaban and dabigatran. Conclusion: Anticoagulation therapy resumption is recommended, with resumption being considered between 7 and 14 days following GIB regardless of the therapy chosen. Data for warfarin management after GIB should be applied with caution to direct oral anticoagulants (DOACs) because of the quicker onset and experimental nature of reversal agents. Apixaban may be a preferred option when restarting a DOAC therapy.
Spindle Cell Mucoepidermoid Carcinoma of the Palatine Tonsil With CRTC1-MAML2 Fusion Transcript: Report of a Rare Case in a 17-Year-Old Boy and a Review of the Literature
Authors: Goh Giap Hean , Lim Chwee Ming , Vanacek Tomas , Michal Michal , Petersson Fredrik
Published: June 2017

Mucoepidermoid carcinoma (MEC) with a predominant spindle cell composition occurring in the palatine tonsil is exceedingly rare. We present a case of a 17-year-old boy with an uncommon spindle cell variant of MEC arising in the palatine tonsil. Histologically, the tumor showed a solid, noncystic architecture and was composed of a predominant population of bland spindle to fusiform cells arranged in organoid nests with interspersed goblet cells and focal areas of ductular structures. Reverse transcriptase polymerase chain reaction and fluorescence in situ hybridization (FISH) revealed the presence of a t(11;19) CRTC1-MAML2 gene fusion in this rare variant of MEC. This is the first case report of a spindle cell MEC of the palatine tonsil, with molecular genetic confirmation. It illustrates the importance of awareness and recognition of this uncommon histological variant of MEC, which will help establish appropriate treatment and prognostication.
Item Response Theory Analysis of the Psychopathic Personality Inventory–Revised
Authors: Eichenbaum Alexander E. , Marcus David K. , French Brian F.
Published: June 2017

This study examined item and scale functioning in the Psychopathic Personality Inventory–Revised (PPI-R) using an item response theory analysis. PPI-R protocols from 1,052 college student participants (348 male, 704 female) were analyzed. Analyses were conducted on the 131 self-report items comprising the PPI-R’s eight content scales, using a graded response model. Scales collected a majority of their information about respondents possessing higher than average levels of the traits being measured. Each scale contained at least some items that evidenced limited ability to differentiate between respondents with differing levels of the trait being measured. Moreover, 80 items (61.1%) yielded significantly different responses between men and women presumably possessing similar levels of the trait being measured. Item performance was also influenced by the scoring format (directly scored vs. reverse-scored) of the items. Overall, the results suggest that the PPI-R, despite identifying psychopathic personality traits in individuals possessing high levels of those traits, may not identify these traits equally well for men and women, and scores are likely influenced by the scoring format of the individual item and scale.
Anesthetic Management of Patients Undergoing Percutaneous Endocardial and Epicardial Left Atrial Appendage Occlusion
Authors: Husain Zeena , Safavi-Naeini Payam , Rasekh Abdi , Razavi Mehdi , Collard Charles D. , Anton James M. , Tolpin Daniel A.
Published: June 2017

Atrial fibrillation is the most common cardiac arrhythmia in adults affecting almost 6 million adults in the United States. The 2 most common comorbidities associated with atrial fibrillation are heart failure and thromboembolic events. Heart failure symptoms may be treated with rate control, antiarrhythmic medications or by catheter ablation. Unfortunately, despite optimal medical management, thromboembolic events still occur. Recently, there has been a great deal of interest and innovation in finding an alternative to chronic anticoagulation. Several percutaneous left atrial appendage occlusion devices have been developed over recent years, some of which have proven to be noninferior to anticoagulation in preventing strokes in atrial fibrillation patients. The 2 most widely used left atrial appendage occlusion devices are the WATCHMAN (Atritech Inc, Plymouth, MN, USA) and the LARIAT (SentreHEART, Palo Alto, CA, USA) devices. After a detailed description of the procedures, the anesthetic considerations of each procedure and management of specific adverse events are discussed within this review.
Modified foam cores for full thermoplastic composite sandwich structures
Authors: Grünewald Jonas , Orth Tilman , Parlevliet Patricia , Altstädt Volker
Published: June 2017

Full thermoplastic composite sandwich structures with a foam core offer the possibility to be manufactured by fusion bonding in significant shorter cycle times than thermoset-based sandwiches. However, the application of foam cores results in lower mechanical properties such as compression and shear strength compared to honeycomb cores, therefore foam-based sandwiches cannot compete with sandwich structures based on Aramid/phenolic honeycomb cores, the current state of the art. In order to improve the mechanical performance of foam core-based sandwiches while maintaining their advantages, concepts to reinforce the foams were developed in this study. By introducing rods either orthogonally or diagonally to the skin plane, which are fusion bonded to the skins during processing, the compression and shear properties can be improved by up to 1000% and 72%, respectively. Even when correcting for the weight increase, an improved specific compression strength could be achieved. And therefore, the pinning looks especially promising when only applied locally in highly loaded areas for example.
The Effects of Medication on Activity and Rehabilitation of Older People – Opportunities and Risks
Authors: Clarke Clare L , Witham Miles D
Published: June 2017

Multiple medication use, or polypharmacy, is common in people undergoing rehabilitation. Polypharmacy is also common in older people, where it has the potential to impact on habitual physical activity. Despite this, the interactions between medication, disease, activity, and rehabilitation outcomes are insufficiently researched. In this review, we consider common classes of medications that can affect physical activity levels and outcomes of rehabilitation. We consider medications that improve disease processes and improve limiting symptoms (eg, breathlessness in heart failure and lung disease, pain in arthritis), unwanted side effects of medications (eg, central slowing caused by opioids and hypnotics), and also medication classes that might have the ability to improve activity and rehabilitation outcomes via beneficial effects on neuromuscular function (eg, angiotensin-converting enzyme inhibitors). We conclude by giving practical advice on how to review and optimise medication use to support habitual physical activity and ensure the best results from rehabilitation.