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The technology in cryotechnology. CRYO LETTERS 2023; 44:314-326. [PMID: 38311925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
The process of freezing biological material at extremely low temperatures is known as cryopreservation. To ensure the preservation of cells and tissues over an extended period of time, low temperatures are applied since biological processes, including the biochemical ones, come to a halt under cryogenic conditions and thus it is possible to maintain their structural and functional integrity. The field of cryopreservation gained more prominence in the 20th century and emerged as an unavoidable technology for different applications such as cell therapy, tissue engineering, or assisted fertilization. In this work we provide an overview of various technologies in the field of cryotechnology with regard to the freezing, storage and thawing of living cells. The first part covers the freezing process, starting with cryoprotective agents regarding their protection mechanisms and compositions, passing by cryo-imaging, micro-fluidic systems, and the currently available freezing and biobanking equipment. The second part focusses on the thawing process as well as the hypothermic preservation for the short-term storage of biological materials and constructs. Doi.org/10.54680/fr23610110112.
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Prevention of Aortic Graft Infections Using Therapeutic Bacteriophages. Thorac Cardiovasc Surg 2022. [DOI: 10.1055/s-0042-1742850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Contrast-enhanced nano-CT reveals soft dental tissues and cellular layers. Int Endod J 2021; 54:1275-1288. [PMID: 33829522 DOI: 10.1111/iej.13527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 04/05/2021] [Indexed: 02/01/2023]
Abstract
AIM To introduce a methodology designed to simultaneously visualize dental ultrastructures, including cellular and soft tissue components, by utilizing phosphotungstic acid (PTA) as a contrast-enhancement agent. METHODOLOGY Sound third molars were collected from healthy human adults and fixed in 4% buffered paraformaldehyde. To evaluate the impact of PTA in concentrations of 0.3%, 0.7% and 1% on dental soft and hard tissues for CT imaging, cementum and dentine-pulp sections were cut, dehydrated and stained with immersion periods of 12, 24 h, 2 days or 5 days. The samples were scanned in a high-resolution nano-CT device using pixel sizes down to 0.5 µm to examine both the cementum and pulpal regions. RESULTS Dental cementum and periodontium as well as odontoblasts and predentine were made visible through PTA staining in high-resolution three-dimensional nano-CT scans. Different segments of the tooth required different staining protocols. The thickness of the cementum could be computed over the length of the tooth once it was made visible by the PTA-enhanced contrast, and the attached soft tissue components of the interior of the tooth could be shown on the dentine-pulp interface in greater detail. Three-dimensional illustrations allowed a histology-like visualization of the sections in all orientations with a single scan and easy sample preparation. The segmentation of the sigmoidal dentinal tubules and the surrounding dentine allowed a three-dimensional investigation and quantitative of the dentine composition, such as the tubular lumen or the ratio of the tubular lumen area to the dentinal surface. CONCLUSION The staining protocol made it possible to visualize hard tissues along with cellular layers and soft tissues in teeth using a laboratory-based nano-CT technique. The protocol depended on both tissue type and size. This methodology offers enhanced possibilities for the concomitant visualization of soft and hard dental tissues.
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Factors determining microbial colonization of liquid nitrogen storage tanks used for archiving biological samples. Appl Microbiol Biotechnol 2019; 104:131-144. [PMID: 31781817 PMCID: PMC6942587 DOI: 10.1007/s00253-019-10242-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/25/2019] [Accepted: 11/04/2019] [Indexed: 01/19/2023]
Abstract
The availability of bioresources is a precondition for life science research, medical applications, and diagnostics, but requires a dedicated quality management to guarantee reliable and safe storage. Anecdotal reports of bacterial isolates and sample contamination indicate that organisms may persist in liquid nitrogen (LN) storage tanks. To evaluate the safety status of cryocollections, we systematically screened organisms in the LN phase and in ice layers covering inner surfaces of storage tanks maintained in different biobanking facilities. We applied a culture-independent approach combining cell detection by epifluorescence microscopy with the amplification of group-specific marker genes and high-throughput sequencing of bacterial ribosomal genes. In the LN phase, neither cells nor bacterial 16S rRNA gene copy numbers were detectable (detection limit, 102 cells per ml, 103 gene copies per ml). In several cases, small numbers of bacteria of up to 104 cells per ml and up to 106 gene copies per ml, as well as Mycoplasma, or fungi were detected in the ice phase formed underneath the lids or accumulated at the bottom. The bacteria most likely originated from the stored materials themselves (Elizabethingia, Janthibacterium), the technical environment (Pseudomonas, Acinetobacter, Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus). In single cases, bacteria, Mycoplasma, fungi, and human cells were detected in the debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.
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Abstract
To investigate the calcification behavior of different bioprosthetic heart valves and verify possible hypotheses of the etiology of valve calcification, an accelerated pulse tester for bioprostheses was developed, whereby up to ten valves can be tested under identical test conditions. Each valve was mounted in a separate compartment on a piston and cyclically moved through a calcifying solution at frequencies of up to 800/min at 37°C. An appropriate calcifying solution was evaluated by incubation tests of bovine and porcine tissue. Calcification was confirmed by measuring Ca and phosphate depletion by atomic absorption spectroscopy, von Kossa staining, EDAX, and microradiography. The first tests were successfully carried out on porcine valves that had been nondestructively assessed for tissue/stress anomalies by holographic interferometry prior to the calcification test. The tests showed that 75% of irregular fringe pattern areas corresponded to the calcification areas.
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The Impact of Thrombus Size and Localization on Acoustic Signals in Ventricular Assist Devices. Thorac Cardiovasc Surg 2017. [DOI: 10.1055/s-0037-1598792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Effects of cryopreservation on the epigenetic profile of cells. Cryobiology 2017; 74:1-7. [DOI: 10.1016/j.cryobiol.2016.12.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 11/08/2016] [Accepted: 12/08/2016] [Indexed: 12/11/2022]
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Cryobiological parameters of multipotent stromal cells obtained from different sources. Cryobiology 2017; 74:93-102. [DOI: 10.1016/j.cryobiol.2016.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 11/10/2016] [Accepted: 11/26/2016] [Indexed: 11/26/2022]
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Cell and tissue encapsulation in alginate for safe cryopreservation. Cryobiology 2016. [DOI: 10.1016/j.cryobiol.2016.09.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cryopreservation alters the histone post-translational modifications of stem cells. Cryobiology 2016. [DOI: 10.1016/j.cryobiol.2016.09.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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The impact of sucrose pretreatment on survival of mesenchymal stromal cells, cryopreserved in suspension and adherent state. Cryobiology 2016. [DOI: 10.1016/j.cryobiol.2016.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cryopreservation of monkey stem cells: Development of safe and efficacious protocols. Cryobiology 2016. [DOI: 10.1016/j.cryobiol.2016.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Active control of the nucleation temperature enhances freezing survival of multipotent mesenchymal stromal cells. Cryobiology 2015; 71:384-90. [PMID: 26499840 DOI: 10.1016/j.cryobiol.2015.10.145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 10/15/2015] [Accepted: 10/19/2015] [Indexed: 02/03/2023]
Abstract
Cryopreservation is a technique that has been extensively used for storage of multipotent mesenchymal stromal cells (MSCs) in regenerative medicine. Therefore, improving current cryopreservation procedures in terms of increasing cell viability and functionality is important. In this study, we optimized the cryopreservation protocol of MSCs derived from the common marmoset Callithrix jacchus (cj), which can be used as a non-human primate model in various pathological and transplantation studies and have a great potential for regenerative medicine. We have investigated the effect of the active control of the nucleation temperature using induced nucleation at a broad range of temperatures and two different dimethylsulfoxide concentrations (Me2SO, 5% (v/v) and 10%, (v/v)) to evaluate the overall effect on the viability, metabolic activity and recovery of cells after thawing. Survival rate and metabolic activity displayed an optimum when ice formation was induced at -10 °C. Cryomicroscopy studies indicated differences in ice crystal morphologies as well as differences in intracellular ice formation with different nucleation temperatures. High subzero nucleation temperatures resulted in larger extracellular ice crystals and cellular dehydration, whereas low subzero nucleation temperatures resulted in smaller ice crystals and intracellular ice formation.
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Electrospun vascular grafts with anti-kinking properties. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2015. [DOI: 10.1515/cdbme-2015-0125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractOne of the major challenges in developing appropriate vascular substitutes is to produce a graft that adapts to the biological and mechanical conditions at the application or implantation site. One approach is the use of tissue engineered electrospun grafts pre-seeded with autologous cells. However, bending stresses during in vivo applications could lead to kinking of the graft which may result in life-threatening stenosis. The aim of this study was to develop an electrospun vascular graft consisting of biodegradable polymers which can reduce or prevent kinking, due to their higher flexibility. In order to improve the bendability of the grafts, various electrospinning collectors were designed using six different patterns. Subsequently, the grafts were examined for scaffold morphology, mechanical strength and bendability. Scaffolds spun on a collector structured with a v-shaped thread (flank angle of 120°) showed a homogenous and reproducible fiber deposition as compared to the unstructured reference sample. The results of the tensile tests were comparable to the unstructured reference sample, supporting the first observation. Studies on bendability were performed using a custom made flow-bending test setup. It was shown that the flow through the v-shaped grafts was reduced to less than 45 % of the reference value even after bending the graft to an angle of 140°. In contrast, the flow through an unstructured graft was reduced to more than 50 % after bending to an angle of 55°. The presented data demonstrate the need for optimizing the bendability of the commonly used electrospun vascular grafts. Using of macroscopic v-shaped collectors is a promising solution to overcome the issue of graft kinking.
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A novel coaxial nozzle for in-process adjustment of electrospun scaffolds’ fiber diameter. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2015. [DOI: 10.1515/cdbme-2015-0027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractElectrospinning is a versatile method of producing micro- and nanofibers deposited in mats used as scaffolds for tissue engineering. Depending on the application, single or coaxial electrospinning can be used. Coaxial electrospinning enables the use of a broad spectrum of materials, the fabrication of hollow or core/shell fibers and an automatisation of the entire electrospinning process. In this regard, the design of coaxial nozzles plays a major role in a standardized as well as tailor-made scaffold fabrication. For this purpose an optimised coaxial nozzle has been designed and fabricated. Furthermore, tests have been carried out to validate the new nozzle design. With the use of the costum-made nozzle polymer concentration could be varied in a gradual manner. The variation in polymer concentration lead to fiber diameters between 0.75 to 3.25 μm. In addition, an increase in rotating velocity lead to an increase in fiber alignment as well as a slight decrease in fiber diameter. The demonstrated modifications of coaxial electrospinning proved to be a powerful tool for in-process adjustments of scaffold fabrication.
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The use of an icebindingprotein out of the snowflea Hypogastrura harveyi as a cryoprotectant in the cryopreservation of mesenchymal stem cells. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2015. [DOI: 10.1515/cdbme-2015-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Today researchers look for a possibility to keep cells for a long time without losing their viability. For that cryopreservation is often used. In this process it is necessary that the cells are not destroyed so cryoprotective agents (CPA) are needed. At the moment 5 to 10 % dimethylsulfoxide (DMSO) is mostly used, but this chemical is cytotoxic to the cells. So an alternative is needed. In this work experiments are made with an icebindingprotein (IBP) of Hypogastrura harveyi, as an alternative to DMSO. It was shown in previous studies that this protein isn’t cytotoxic for the cells, with crude extract and purified inclusion bodies it even seems that the mixtures have a positive effect on growth and proliferation. As a first step the protein was produced heterologous in E. coli and then the crude extract and the purified inclusion bodies were used for experiments on the influence of the IBP on the cryopreservation of mesenchymal stem cells from the common marmoset monkey Callithrix jacchus. In the process it was found that the protein could not replace DMSO completely. But it was possible to show that the DMSO-concentration can be reduced by adding the IBP.
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Track E. Cellular, Tissue and Bioengineering. BIOMED ENG-BIOMED TE 2015; 60 Suppl 1:s103-17. [DOI: 10.1515/bmt-2015-5004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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C-2008. Cryobiology 2014. [DOI: 10.1016/j.cryobiol.2014.09.355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Core/Shell electrospun fibers as biodegradable scaffolds for sustained drug delivery in Wound Healing applications. Pneumologie 2014. [DOI: 10.1055/s-0034-1376854] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Chitosan/Polycaprolactone electrospun biodegradable scaffolds for Cardiovascular Tissue Engineering. Pneumologie 2014. [DOI: 10.1055/s-0034-1376855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Endothelialization of electrospun polycaprolactone (PCL) small caliber vascular grafts spun from different polymer blends. J Biomed Mater Res A 2014; 102:4500-9. [PMID: 24532056 DOI: 10.1002/jbm.a.35123] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/31/2014] [Accepted: 02/11/2014] [Indexed: 11/09/2022]
Abstract
Small caliber vascular grafts represent a challenge to material scientists. In contrast to large caliber grafts, prostheses with diameter <6 mm, lead to increased hemodynamic disturbances and thrombogenic complications. Thus, endothelialization of small caliber grafts should create a compatible interface for hemodynamic processes. The purpose of our study was to compare different compositions of electrospun scaffolds with conventional ePTFE grafts with an inner diameter of 4 mm as well as different pre-coatings to create an optimized physiological interface for endothelialization. Polycaprolactone, polylactide, and polyethylenglycol (PCL/PLA and PCL/PLA/PEG) electrospun grafts and ePTFE grafts were pre-coated with blood, gelatine or fibronectin and seeded with endothelial cells from the human term placenta. Best results were obtained with fibronectin-coated PCL/PLA/PEG grafts. Here, the number of attached viable cells was 78-81% higher than on fibronectin pre-treated ePTFE grafts. Cells attached to PCL/PLA/PEG grafts appeared in physiological cobblestone morphology. Viability analysis showed a high cell viability of more than 98%. Fibronectin-coated PCL/PLA/PEG grafts may be a promising improvement to conventionally used ePTFE grafts.
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043 Antioxidants as additional additives to CPA may help to minimize epigenetic modifications caused by Me2SO. Cryobiology 2013. [DOI: 10.1016/j.cryobiol.2013.09.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Proof of Concept of a New Glucose Sensing Technology: Color-Changing Hydrogels Including au Nanoparticles. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-C/bmt-2013-4063/bmt-2013-4063.xml. [PMID: 24042688 DOI: 10.1515/bmt-2013-4063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Solving Biocompatibility Layer by Layer: Designing Scaffolds for Tissues. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-C/bmt-2013-4065/bmt-2013-4065.xml. [PMID: 24042739 DOI: 10.1515/bmt-2013-4065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Antioxidantien als Strategie zur Optimierung der Kryokonservierung von Stammzellen für das Tissue Engineering. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-H/bmt-2013-4200/bmt-2013-4200.xml. [DOI: 10.1515/bmt-2013-4200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Magnesium as a biomaterial and its biological interactions. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-C/bmt-2013-4066/bmt-2013-4066.xml. [DOI: 10.1515/bmt-2013-4066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Dynamische In-Vitro-Studie zur Strömungsabhängigkeit der Degradationsrate von Magnesium. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-C/bmt-2013-4103/bmt-2013-4103.xml. [DOI: 10.1515/bmt-2013-4103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Optimization of a test setup for examining blood damage caused by high shear forces. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Dynamic in vitro hemocompatibility testing – improving the signal to noise ratio. ACTA ACUST UNITED AC 2012. [DOI: 10.1515/bmt-2012-4211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Dimethyl sulfoxide and ethylene glycol promote membrane phase change during cryopreservation. CRYO LETTERS 2011; 32:148-157. [PMID: 21766144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fourier transform infrared spectroscopy (FTIR) and cryomicroscopy were used to study the effects of dimethyl sulfoxide and ethylene glycol on cell pellets of human pulmonary microvascular endothelial cells during freezing from 4 degree C to -60 degree C at 1 degree C per min. FTIR analysis showed that membranes undergo a phase change in the presence of cryoprotective agents (CPAs) which was not observed in the absence of CPAs. Cryomicroscopy revealed the formation of intracellular ice and concomitant cell volume changes. Intracellular ice was detected in the majority of the cells both in the presence and absence of CPAs. Membrane phase changes were found to be most pronounced at intermediate concentrations of cryoprotective agents; for dimethyl sulfoxide at around 1 M and for ethylene glycol at around 1.5 M. At those concentrations cell survival after thawing exhibited a maximum. The results indicate that CPAs promote rather than prevent cell dehydration during freezing.
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Shear stress mechanotransduction in Endothelial Progenitor Cells (EPC) using a cone plate rheometer. Thorac Cardiovasc Surg 2011. [DOI: 10.1055/s-0030-1268963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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107. Liposomes for biopreservation of human erythrocytes. Cryobiology 2010. [DOI: 10.1016/j.cryobiol.2010.10.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Neue Implantate: Funktionalität versus Regeneration. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201050031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Stammzellbasierte zelltherapeutische Implantate: Entwicklung eines Herstellungs- und Kryokonservierungsverfahrens. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201050007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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IN VITRO UNTERSUCHUNGEN ZUR HÄMOKOMPATIBILITÄT VON HOCHLEISTUNGSPOLYMEREN IM FLOWMODELL. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.2001.46.s1.222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Homo bionicus: Funktionalität vs.Regeneration. CHEM-ING-TECH 2009. [DOI: 10.1002/cite.200950049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Impact of valve calcification on systolic and diastolic valvular function--an in vitro model. THE JOURNAL OF CARDIOVASCULAR SURGERY 2008; 49:817-824. [PMID: 19043396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
AIM Despite continuous development of anticalcification treatment for bioprosthetic valves, calcification remains one major cause of structural failure. The aim of this study is to investigate changes in hemodynamic performance and leaflet kinematics in progressively calcified pericardial and porcine aortic valve prostheses. METHODS Five pericardial (Edwards Perimount Magna) and 5 porcine (Medtronic Mosaic Ultra) aortic valve prostheses (Ø23 mm) were exposed to a high concentration Calcium-phosphate fluid in an in vitro pulse duplicator (300 cycles/minute) for 6 weeks. The prostheses were removed weekly and tested in an artificial circulation system (70 beats/min, Cardiac Output 5 l/min). All prostheses underwent X-ray, computed tomography (CT)-Scan and photographic examination for evaluation of progressive calcification. Leaflet kinematics were visualized with a high-speed camera. RESULTS Pericardial valves demonstrated faster degeneration with significantly larger radiographic areas of leaflet calcification (16.5+/-4.3% versus 5.6%+/-2.0%) and also significantly higher Ca-uptake (170+/-71 microg/mg versus 103+/-49 microg/mg) after 6 weeks. Despite degeneration systolic function remained superior for pericardial valves (mean effective orifice area [EOA] 1.52+/-0.05 versus 1.28+/-0.11 cm2, P<0.01), but leaflet kinematics showed longer closing times (135+/-11 msec versus 85+/-9 msec after 6 weeks) accompanied by higher regurgitant flow (7.8+/-1.12 mL versus 1.2+/-0.28 mL, P<0.001). CONCLUSION In vitro pericardial valves calcified faster and more severe than porcine valves leading to impaired diastolic function with prolongation of closing times and higher closing volume. Systolic function remained almost undisturbed by the calcification process. As a consequence in clinical settings, follow-up examinations for structural valve deterioration in porcine valves should focus on systolic performance, in pericardial valves on diastolic function.
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Measurements of micro- and macromixing in liquid mixtures of reacting components using two-colour laser induced fluorescence. Chem Eng Sci 2008. [DOI: 10.1016/j.ces.2007.10.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Biological Scaffold Modifications by Gamma Sterilization. CHEM-ING-TECH 2008. [DOI: 10.1002/cite.200750734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Mehrskalige Analyse von Transportprozessen mit Hilfe von laseroptischen Methoden und CFD. CHEM-ING-TECH 2008. [DOI: 10.1002/cite.200750514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Biomaterialien im Spagat zwischen Forschung und Anwendung. CHEM-ING-TECH 2007. [DOI: 10.1002/cite.200750323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Prediction of Mechanical Blood Damage in Extracorporal Devices. CHEM-ING-TECH 2007. [DOI: 10.1002/cite.200750036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hemodynamic performance and leaflet kinematics of porcine versus pericardial aortic valve prostheses. Thorac Cardiovasc Surg 2007. [DOI: 10.1055/s-2007-967361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Application of a biaxial cellstretcher for cardiovascular tissue engineering. Thorac Cardiovasc Surg 2006. [DOI: 10.1055/s-2006-925638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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