50 research outputs found

    Selbsthilfeorganisationen für seltene Erkrankungen und Gesundheitsversorgung: Gesundheitspolitische Erwartungen und Selbsthilferealität

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    Health policy expects self-help associations to make contributions to the improvement of the healthcare sector. The pilot study has explored the degree of reality of these expectations in a sample of five self-help organizations in the field of rare diseases. The study reveals that the expectations are fulfilled only in part. Self-help organizations enrich the healthcare sector with two specific qualities: their members operate with the special competencies of affected people and they have established a long-lasting cooperation with voluntary professionals. They are often a great help to the people contacting them directly, but, for a number of reasons, their supporting measures are reaching only a part of all affected people. The activities in the field of social participation have to cope with a lack of proper activists. They are able to pursue single projects successfully, but they are facing great problems in mastering the whole agenda of social participation

    Advances in Molecular Quantum Chemistry Contained in the Q-Chem 4 Program Package

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    A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller–Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube

    National Institutes of Health–Sponsored Clinical Islet Transplantation Consortium Phase 3 Trial: Manufacture of a Complex Cellular Product at Eight Processing Facilities

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    Eight manufacturing facilities participating in the National Institutes of Health–sponsored Clinical Islet Transplantation (CIT) Consortium jointly developed and implemented a harmonized process for the manufacture of allogeneic purified human pancreatic islet (PHPI) product evaluated in a phase 3 trial in subjects with type 1 diabetes. Manufacturing was controlled by a common master production batch record, standard operating procedures that included acceptance criteria for deceased donor organ pancreata and critical raw materials, PHPI product specifications, certificate of analysis, and test methods. The process was compliant with Current Good Manufacturing Practices and Current Good Tissue Practices. This report describes the manufacturing process for 75 PHPI clinical lots and summarizes the results, including lot release. The results demonstrate the feasibility of implementing a harmonized process at multiple facilities for the manufacture of a complex cellular product. The quality systems and regulatory and operational strategies developed by the CIT Consortium yielded product lots that met the prespecified characteristics of safety, purity, potency, and identity and were successfully transplanted into 48 subjects. No adverse events attributable to the product and no cases of primary nonfunction were observed

    Pig Pancreas Oxygenation at 20°C Increases Islet ATP Generation but Deteriorates Islet Function

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    Successful pancreas preservation during storage in oxygenated perfluorodecalin (PFD) is mainly related to oxidative ATP generation during storage. Increasing the storage temperature would accelerate this process essential for resuscitation of ischemically damaged pancreatic tissue. The present study aimed at comparing islet isolation outcome from adult pig pancreata preserved in oxygenated PFD by means of a one-layer method during storage on ice or at 20 degrees C. Resected pancreata were intraductally flushed with cold UW solution and promptly processed (n = 6) or stored for 3 h in continuously oxygenated PFD at 4 degrees C (n = 5) or 20 degrees C (n = 7). Prior to digestion-filtration pancreata were intraductally injected with UW supplemented with Serva collagenase NB8 and neutral protease. Islet quality assessment determined viability, glucose stimulation index, mitochondrial activity, intracellular ATP content, and transplant function in diabetic nude mice. Pancreata oxygenated for 3 h at 20 degrees C yielded islet numbers similar to organs oxygenated at 4 degrees C. Compared to a storage temperature of 20 degrees C, preservation at 4 degrees C reduced islet ATP content (p < 0.05) as well as islet viability (p < 0.05). Nevertheless, PFD storage at 20 degrees C decreased insulin response to glucose compared to unstored pancreata (p < 0.05). In contrast to unstored pancreata or cold-stored organs, transplantation of islets isolated after oxygenation at 20 degrees C was characterized by an early loss of transplant function in 50% of recipients (p < 0.05). The present study demonstrates that PFD storage at 20 degrees C enhances islet ATP synthesis within a short period of oxygenation but deteriorates islet function. We conclude that the present data reflect an equilibration between reduced depression of metabolic activity resulting in damage of islets and temperature-stimulated acceleration of ATP synthesis. Future studies are required to adjust the optimum storage temperature for pancreas oxygenation in different species

    Quantifying the Effects of Different Neutral Proteases on Human Islet Integrity

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    Efficient islet release from the pancreas requires the combination of collagenase, neutral protease (cNP), or thermolysin (TL). Recently, it has been shown that clostripain (CP) may also contribute to efficient islet release from the human pancreas. The aim of this study was to evaluate the impact of these proteases on human islet integrity in a prospective approach. Islets were isolated from the pancreas of 10 brain-dead human organ donors. Purified islets were precultured for 3 to 4 d at 37 degrees C to ensure that preparations were cleared of predamaged islets, and only integral islets were subjected to 90 min of incubation at 37 degrees C in Hank's balanced salt solution supplemented with cNP, TL, or CP. The protease concentrations were calculated for a pancreas of 100 g trimmed weight utilizing 120 dimethyl-casein units of cNP, 70,000 caseinase units of TL, or 200 benzoyl-Larginine- ethyl-ester units of CP (1x). These activities were then increased both 5 x and 10 x. After subsequent 24-h culture in enzyme-free culture medium, treated islets were assessed and normalized to sham-treated controls. Compared with controls and CP, islet yield was significantly reduced by using the 5 x activity of cNP and TL, inducing also fragmentation and DNA release. Viability significantly decreased not until adding the 1 x activity of cNP, 5 x activity of TL, or 10 x activity of CP. Although mitochondrial function was significantly lowered by 1 x cNP and 5 x TL, CP did not affect mitochondria at any concentration. cNP-and TL-incubated islets significantly lost intracellular insulin already at 1 x activity, while the 10 x activity of CP had to be added to observe a similar effect. cNP and TL have a similar toxic potency regarding islet integrity. CP also induces adverse effects on islets, but the toxic threshold is generally higher. We hypothesize that CP can serve as supplementary protease to minimize cNP or TL activity for efficient pancreas digestion

    Comparison of Neutral Proteases and Collagenase Class I as Essential Enzymes for Human Islet Isolation

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    Background. Efficient islet isolation requires synergistic interaction between collagenase class I (CI) and class II (CII). The CI degradation alters the ratio between CI and CII and is responsible for batch-to-batch variations. This study compares the role of neutral protease (NP) plus clostripain (CP) with CI as essential enzymes for human islet isolation. Methods. Human islets were isolated using 4 different enzyme mixtures composed of CII plus either intact (CI-115) or degraded CI (CI-100). Blends were administered either with or without NP/CP. Purified islets were cultured for 3 to 4 days before islet quality assessment. Results. Whereas using intact CI-115 without NP/CP did not significantly reduce islet yield (3429 +/- 631 vs 3087 +/- 970 islet equivalent/g, nonsignificant), administration of degraded CI-100 without NP/CP decreased islet yield from 3501 +/- 580 to 1312 +/- 244 islet equivalent/g (P < 0.01), doubled the amount of undigested tissue from 11.8 +/- 1.6 to 24.4 +/- 1.2% (P < 0.01) and triplicated the percentage of trapped islets from 7.7 +/- 2.8 to 22.5 +/- 3.6% (P < 0.05). Islet yield did not vary between supplemented CI-115 and CI-100, but was increased using CI-115 when NP/CP was omitted (P < 0.05). A trend toward higher viability and increased secretory insulin response was noted in both CI-100 and CI-115 when NP/CP was not added. Conclusions. This study suggests that NP/CP can compensate reduced CI activity. Future attempts to optimize enzyme blends should consider the possibility to increase the proportion of collagenase CI to reduce the need for potentially harmful NPs

    Coupling saturated and unsaturated flow: comparing the iterative and the non-iterative approach

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    Fully integrated three-dimensional (3D) physically based hydrologic models usually require many computational resources. For many applications, simplified models can be a cost-effective alternative. The 3D models of subsurface flow are often simplified by coupling a 2D groundwater model with multiple 1D models for the unsaturated zone. The crucial part of such models is the coupling between the two model compartments. In this work we compare two approaches for the coupling. One is iterative where the 1D unsaturated zone models go down to the impervious bottom of the aquifer, and the other one is non-iterative and uses a moving lower boundary for the unsaturated zone. In this context we also propose a new way of treating the specific yield, which plays a crucial role in linking the unsaturated and the groundwater model. Both models are applied to three test cases with increasing complexity and analyzed in terms of accuracy and speed compared to fully integrated model runs. The non-iterative approach is faster but does not yield a good accuracy for the model parameters in all applied test cases, whereas the iterative one gives good results in all cases. Which strategy is applied depends on the requirements: computational speed vs. model accuracy

    Comparison of Clostripain and Neutral Protease as Supplementary Enzymes for Human Islet Isolation

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    Although human islet transplantation has been established as valid and safe treatment for patients with type 1 diabetes, the utilization rates of human pancreases for clinical islet transplantation are still limited and substantially determined by the quality and composition of collagenase blends. While function and integrity of collagenase has been extensively investigated, information is still lacking about the most suitable supplementary neutral proteases. The present study compared islet isolation outcome after pancreas digestion by means of collagenase used alone or supplemented with either neutral protease (NP), clostripain (CP), or both proteases. Decent amounts of islet equivalents (IEQ) were isolated using collagenase alone (3090 +/- 550 IEQ/g), or in combination with NP (2340 +/- 450 IEQ/g) or CP (2740 +/- 280 IEQ/g). Nevertheless, the proportion of undigested tissue was higher after using collagenase alone (21.1 +/- 1.1%, P < 0.05) compared with addition of NP (13.3 +/- 2.2%) or CP plus NP (13.7 +/- 2.6%). Likewise, the percentage of embedded islets was highest using collagenase only (13 +/- 2%) and lowest adding NP plus CP (4 +/- 1%, P < 0.01). The latter combination resulted in lowest post-culture overall survival (42.7 +/- 3.9%), while highest survival was observed after supplementation with CP (74.5 +/- 4.8%, P < 0.01). An insulin response toward glucose challenge was present in all experimental groups, but the stimulation index was significantly decreased using collagenase plus NP (2.0 +/- 0.12) compared with supplementation with CP (3.16 +/- 0.4, P < 0.001). This study demonstrates for the first time that it is possible to isolate significant numbers of human islets combining collagenase only with CP. The supplementation with CP is an effective means to substantially reduce NP activity, which significantly decreases survival and viability after culture. This will facilitate the manufacturing of enzyme blends with less harmful characteristics
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