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1.
Chorioallantoic membrane angiogenesis model for tissue engineering: a new twist on a classic model 总被引:4,自引:0,他引:4
Tissue-engineering (TE) applications include the isolation, culture, and seeding of cells into a suitable matrix or scaffold before in vivo transplantation. After transplantation, vascularization of the scaffold is a principal limiting factor for cell viability for the first 6-8 days posttransplantation. A model for systematic analysis of this process has been developed. Fertilized White Leghorn eggs were incubated (at 37.8 degrees C in 60% relative humidity) and opened on day 3 of incubation. Preadipocyte-seeded fibrin constructs were implanted in a specially designed plastic cylinder and placed through the opening on the surface of the chorioallantoic membrane (CAM) on day 8 of incubation. Vascularization of the constructs by chorioallantoic blood vessels was assessed for up to 8 days posttransplantation. The survival rate for embryos receiving transplanted constructs was about 90%. Histology confirmed transplant cell viability at day 4 posttransplantation and vascularization of the constructs by avian endothelial cells began at this time. A new in vivo model to study the effect of angiogenesis in TE constructs, including assessments of viability, proliferation, and differentiation of transplanted cells and biomaterial properties, is presented. Advantages include easy access to the vascular network of the CAM, lack of immunocompetence, low costs, and avoidance of animal experiments. 相似文献
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Joanna J. Listopad Thomas Kammertoens Kathleen Anders Bjoern Silkenstedt Gerald Willimsky Karin Schmidt Anja A. Kuehl Christoph Loddenkemper Thomas Blankenstein 《Proceedings of the National Academy of Sciences of the United States of America》2013,110(6):2276-2281
The contribution of molecules such as perforin, IFN-γ (IFNγ), and particularly Fas ligand (FasL) by transferred CD8+ effector T (TE) cells to rejection of large, established tumors is incompletely understood. Efficient attack against large tumors carrying a surrogate tumor antigen (mimicking a “passenger” mutation) by TE cells requires action of IFNγ on tumor stroma cells to avoid selection of antigen-loss variants. Because “cancer-driving” antigens (CDAs) are rarely counterselected, IFNγ may be expected to be dispensable in elimination of cancers by targeting a CDA. Here, initial regression of large, established tumors required neither IFNγ, FasL, nor perforin by transferred CD8+ TE cells targeting Simian Virus (SV) 40 large T as CDA. However, cytotoxic TE cells lacking IFNγ or FasL could not prevent relapse despite retention of the rejection antigen by the cancer cells. Complete tumor rejection required IFNγ-regulated Fas by the tumor stroma. Therefore, TE cells lacking IFNγ or FasL cannot prevent progression of antigenic cancer because the tumor stroma escapes destruction if its Fas expression is down-regulated. 相似文献
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Erika Assarsson Jason A. Greenbaum Magnus Sundstr?m Lana Schaffer Jennifer A. Hammond Valerie Pasquetto Carla Oseroff R. Curtis Hendrickson Elliot J. Lefkowitz David C. Tscharke John Sidney Howard Grey Steven R. Head Bjoern Peters Alessandro Sette 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(40):E63-E64
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Martina Koch Thorsten Wiech Matthias Marget Sven Peine Hansjrg Thude Eike G. Achilles Lutz Fischer Anja Lehnhardt Friedrich Thaiss Bjoern Nashan 《Clinical transplantation》2015,29(11):1021-1028
ABO‐incompatible (ABOi) kidney transplantation (KTx) has become an accepted therapeutic option in renal replacement therapy for patients without a blood group‐compatible living donor. Using different desensitization strategies, most centers apply B‐cell depletion with rituximab and maintenance immunosuppression (IS) with tacrolimus and mycophenolic acid. This high load of total IS leads to an increased rate of surgical complications and virus infections in ABOi patients. Our aim was to establish ABOi KTx using an immunosuppressive regimen, which is effective in preventing acute rejection without increasing the risk for viral infections. Therefore, we selected a de novo immunosuppressive protocol with low‐dose calcineurin inhibitor and the mTOR inhibitor everolimus for our ABOi program. Here, we report the first 25 patients with a complete three‐yr follow‐up treated with this regimen. Three‐yr patient survival and graft survival were 96% and 83%. The rate of acute T‐cell‐mediated rejections was low (12%). Cytomegalovirus (CMV) infection was evident in one patient only (4%). Surgical complications were common (40%), but mild in 80% of cases. We demonstrate that ABOi KTx with a de novo mTOR inhibitor‐based regimen is feasible without severe surgical or immunological complications and a low rate of viral infections. 相似文献
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Bjoern Moosmann Philippe Bisel Folker Westphal Maurice Wilde Jürgen Kempf Verena Angerer Volker Auwrter 《Drug testing and analysis》2019,11(3):541-549
The number of newly appearing benzodiazepine derivatives on the new psychoactive substances (NPS) drug market has increased over the last couple of years totaling 23 ‘designer benzodiazepines’ monitored at the end of 2017 by the European Monitoring Centre for Drugs and Drug Addiction. In the present study, three benzodiazepines [flunitrazolam, norflurazepam, and 4′‐chlorodiazepam (Ro5–4864)] offered as ‘research chemicals' on the Internet were characterized and their main in vitro phase I metabolites tentatively identified after incubation with pooled human liver microsomes. For all compounds, the structural formula declared by the vendor was confirmed by gas chromatography?mass spectrometry (GC–MS), liquid chromatography?tandem mass spectrometry (LC MS/MS), liquid chromatography?quadrupole time of flight?mass spectrometry (LC?QTOF?MS) analysis and nuclear magnetic resonance (NMR) spectroscopy. The metabolic steps of flunitrazolam were monohydroxylation, dihydroxylation, and reduction of the nitro function. The detected in vitro phase I metabolites of norflurazepam were hydroxynorflurazepam and dihydroxynorflurazepam. 4’‐Chlorodiazepam biotransformation consisted of N‐dealkylation and hydroxylation. It has to be noted that 4′‐chlorodiazepam and its metabolites show almost identical LC–MS/MS fragmentation patterns to diclazepam and its metabolites (delorazepam, lormetazepam, and lorazepam), making a sufficient chromatographic separation inevitable. Sale of norflurazepam, the metabolite of the prescribed benzodiazepines flurazepam and fludiazepam, presents the risk of incorrect interpretation of analytical findings. 相似文献