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Mechanical Dissociation (mechanical + dissociation)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Mechanical Dissociation of Swine Liver to Produce Organoid Units for Tissue Engineering and In Vitro Disease Modeling

ARTIFICIAL ORGANS, Issue 1 2010
Katayun Irani
Abstract The complex intricate architecture of the liver is crucial to hepatic function. Standard protocols used for enzymatic digestion to isolate hepatocytes destroy tissue structure and result in significant loss of synthetic, metabolic, and detoxification processes. We describe a process using mechanical dissociation to generate hepatic organoids with preserved intrinsic tissue architecture from swine liver. Oxygen-supplemented perfusion culture better preserved organoid viability, morphology, serum protein synthesis, and urea production, compared with standard and oxygen-supplemented static culture. Hepatic organoids offer an alternative source for hepatic assist devices, engineered liver, disease modeling, and xenobiotic testing. [source]

A Rare type of Ventricular Oversensing in ICD Therapy,Inappropriate ICD Shock Delivery Due to Triple Counting

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2010
MICHAEL GUENTHER M.D.
Irregular sensing by triple counting of wide QRS complexes resulted in inappropriate shocks in a patient with a biventricular implantable cardioverter defibrillator (ICD): A 66-year-old male patient with ischemic cardiomyopathy, left bundle branch block, and impaired left ventricular function received a biventricular ICD for optimal therapy of heart failure (CHF). Two years after implantation, the patient experienced recurrent unexpected ICD shocks without clinical symptoms of malignant tachyarrhythmia, or worsened CHF. The patient's condition rapidly worsened, with progressive cardiogenic shock and electrical,mechanical dissociation. After unsuccessful resuscitation of the patient the interrogation of the ICD showed an initial triple counting of extremely wide and fragmented QRS complexes with inappropriate shocks. (PACE 2010; 33:e17,e19) [source]

Generation and Characterization of Embryonic Stem-Like Cell Lines Derived from In Vitro Fertilization Buffalo (Bubalus bubalis) Embryos

REPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2010
B Huang
Contents In the present study, buffalo embryonic stem-like (ES-like) cell lines were successfully isolated, cultured and characterized. From a total of 92 normal buffalo embryos obtained by in vitro fertilization, 18 were morulae, 33 were blastocyst and 41 were hatched blastocyst, the inside of morulae or inner cell masses of blastocysts were isolated mechanically and cultured onto mitomocin-C-inactivated buffalo embryonic fibroblasts as feeder layers. Alkaline phosphatase (AP) of ES-like cells, as well as the specific stage embryonic antigen SSEA-1, SSEA-3, SSEA-4 and transcription factor OCT-4, was used to evaluate the characterization of the cells. The spontaneous differentiation of ES-like cells was induced by culturing on leukaemia inhibitory factor-free medium for more than 2 weeks without passage. To evaluate mark gene expression, total RNA was extracted from cells, and specific primers were used for reverse transcriptase-polymerase chain reaction (RT-PCR). After 8,10 days of culture, primary ES-like cell colonies were formed in 0% (0/18) of morulae, 24.24% (8/33) of blastocysts and 60.98% (25/41) of hatched blastocysts, respectively. The forming rate of primary ES-like cells colonies in hatched blastocyst group was significantly (p < 0.05) higher than the obtained for other groups. Two ES-like cell lines could survive to eight passages at least by using the method of mechanical dissociation, but just three passages by using the method of enzymatic dissociation. The cells formed large, multicellular colonies with distinct boundaries, exhibited many important features of ES/ES-like cells, including positive AP, SSEA-1, SSEA-3 and SSEA-4 activity. Undifferentiated buffalo ES-like cells expressed Oct-4, Nanog, Sox2 gene mRNA. In vitro differentiation experiments had demonstrated that those cells were pluripotent. [source]

Mechanical Dissociation of Swine Liver to Produce Organoid Units for Tissue Engineering and In Vitro Disease Modeling

Passaging Protocols for Mammalian Neural Stem Cells in Suspension Bioreactors

BIOTECHNOLOGY PROGRESS, Issue 2 2002
Arindom Sen
Mammalian neural stem cells (NSC) offer great promise as therapeutic agents for the treatment of central nervous system disorders. As a consequence of the large numbers of cells that will be needed for drug testing and transplantation studies, it is necessary to develop protocols for the large-scale expansion of mammalian NSC. Neural stem cells and early progenitor cells can be expanded in vitro as aggregates in controlled bioreactors using carefully designed media. The first objective of this study was to determine if it is possible to maintain a population of murine neural stem and progenitor cells as aggregates in suspension culture bioreactors over extended periods of time. We discovered that serial passaging of a mixture of aggregates sizes resulted in high viabilities, high viable cell densities, and good control of aggregate diameter. When the NSC aggregates were serially subcultured three times without mechanical dissociation, a total multiplication ratio of 2.9 × 103 was achieved over a period of 12 days, whereas the aggregate size was controlled (mean diameter less than 150 ,m) below levels at which necrosis would occur. Moreover, cell densities of 1.0 × 106 cells/mL were repeatedly achieved in batch culture with viabilities exceeding 80%. The second objective was to examine the proliferative potential of single cells shed from the surface of these aggregates. We found that the single cells, when subcultured, retained the capacity to generate new aggregates, gave rise to cultures with high viable cell densities and were able to differentiate into all of the primary cell phenotypes in the central nervous system. [source]