Tailoring of Hierarchical Porous Freeze Foam Structures

Freeze foaming is a method to manufacture cellular ceramic scaffolds with a hierarchical porous structure. These so-called freeze foams are predestined for the use as bone replacement material because of their internal bone-like structure and biocompatibility. On the one hand, they consist of macrostructural foam cells which are formed by the expansion of gas inside the starting suspension. On the other hand, a porous microstructure inside the foam struts is formed during freezing and subsequent freeze drying of the foamed suspension. The aim of this work is to investigate for the first time the formation of macrostructure and microstructure separately depending on the composition of the suspension and the pressure reduction rate, by means of appropriate characterization methods for the different pore size ranges. Moreover, the foaming behavior itself was characterized by in-situ radiographical and computed tomography (CT) evaluation. As a result, it could be shown that it is possible to tune the macro- and microstructure separately with porosities of 49–74% related to the foam cells and 10–37% inside the struts.     

Zur Physiologie und Pathologie der Wehen

Archives of Gynecology and Obstetrics -     

Blutvergiftung mit erkrankung der herzklappen bei fehlgeburten

Ohne Zusammenfassung     

Diabetes increases pancreatitis induced systemic inflammation but has little effect on inflammation and cell death in the lung

Acute pancreatitis (AP) can lead to a systemic inflammatory response that often results in acute lung injury and single or multiple organ failure. In a previous study we demonstrated that diabetes aggravates the local pathophysiological process during AP. In this study we explore, if diabetes also increases pancreatitis induced systemic inflammation and causes lung injury. Acute pancreatitis was induced in untreated and streptozotocin‐treated diabetic mice by injection of cerulein. Systemic inflammation was studied by IL‐6 ELISA in blood plasma and white blood cell count. Lung inflammation and lung injury were quantified by chloroacetate esterase staining, evaluation of the alveolar cellularity index and cleaved caspase‐3 immunohistochemistry. In normoglycaemic mice AP increased the IL‐6 concentration in plasma and caused lymphocytopenia. Diabetes significantly increased the IL‐6 concentration in plasma and further reduced the number of lymphocytes during AP, whereas diabetes had little effect on these parameters in the absence of pancreatitis. However, diabetes only marginally increased lung inflammation and did not lead to cell death of the lung epithelium during AP. We conclude that diabetes increases parameters of systemic inflammation during AP, but that this increase is insufficient to cause lung injury.     

Incidence and predictors of target vessel revascularization and clinical event rates of the sirolimus-eluting coronary stent (results from the prospective multicenter German Cypher Stent Registry)

Randomized trials have demonstrated the ability of drug-eluting stents to decrease the risk of restenosis after coronary stent implantation. However, the incidences of major cardiovascular/cerebral adverse events (MACCEs) and target vessel revascularization (TVR) during follow-up in a routine clinical setting remain to be determined. We analyzed data of the multicenter German Cypher Stent Registry. From April 2002 to March 2003, 1,726 patients at 93 hospitals who received >/=1 sirolimus-eluting coronary stent were included. Median follow-up was 6.7 months. During follow-up, death occurred in 1.2% of patients (20 of 1,726), nonfatal myocardial infarction in 2.5% (43 of 1,706), and nonfatal stroke in 0.5% (7 of 1,469). TVR was performed in 8.6% of patients, with percutaneous coronary intervention in 7.3% and coronary artery bypass grafting in 1.5%. The overall rate of MACCEs or TVR was 10.8% (186 of 1,726). Independent predictors of TVR were the target vessel being a bypass graft (odds ratio [OR] 2.43, 95% confidence interval [CI] 1.41 to 4.18, p = 0.001), management of >1 lesion during the same intervention (OR 1.75, 95% CI 1.04 to 2.96, p = 0.035), 2- or 3-vessel disease (OR 1.69, 95% CI 1.05 to 2.72, p = 0.030), and age (per decade; OR 0.82, 95% CI 0.69 to 0.98, p = 0.025). These data confirm the safety and effectiveness of using the sirolimus-eluting stent in daily clinical practice. The management of bypass grafts and multiple lesions in 1 session and the presence of multivessel disease were predictors of MACCEs or TVR.     

Virion half-life in chronic hepatitis B infection is strongly correlated with levels of viremia

Analysis of hepatitis B virus (HBV) kinetics with mathematical models may disclose new aspects of HBV infection and host response mechanisms. To determine the kinetics of virion decay from the blood of patients in different phases of chronic infection, we applied mathematical modeling to real-time polymerase chain reaction assays, which enable quantification of viremia and intrahepatic HBV productivity by measuring both copy number and activity of covalently closed circular DNA (relaxed circular DNA/covalently closed circular DNA) in the liver of 80 untreated chronically active HBV carriers (38 hepatitis B e antigen [HBeAg]-positive and 42 HBeAg-negative individuals). We found that the half-life of circulating virions is very fast (median 46 and 2.5 minutes in HBeAg-positive and HBeAg-negative individuals, respectively) and strongly related to viremia, with clearance rates significantly accelerating as viral loads decrease. To investigate whether immune components can influence the kinetics of virion decay, we analyzed viral dynamics in immunodeficient urokinase-type plasminogen activator chimera mice. Virion half-life in mice (range, 44 minutes to >4 hours) was comparable to estimates determined in high viremic carriers, implying that clearance rates in these patients are mostly determined by common nonspecific mechanisms. Notably, the lack of correlation between virion half-life and viremia in mice indicated that immune components significantly accelerate virion clearance rates in individuals with low titers. CONCLUSION: Our analyses suggest that both host defense mechanisms and levels of circulating virions affect the kinetics of HBV decay assessed in the serum of chronic carriers. Identification of the factors affecting clearance rates will be important for future antiviral drug developments and it may give insights into the mechanisms involved in clearance of other chronic infections, such as human immunodeficiency virus and hepatitis C virus.