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Culture Flask (culture + flask)
Selected AbstractsDiscordant influence of amphotericin B on epirubicin cytotoxicity in primary hepatic malignant cells collected by a new primary culture techniqueJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2006ZU-YAU LIN Abstract Background:, The purpose of this prospective study was to investigate whether amphotericin B (AmB) had any potential role in the systemic chemotherapy of primary hepatic malignancy using cancer cells collected by the authors' method of primary culture. Methods:, The specimens obtained by ultrasound-guided fine-needle aspiration biopsy (22 G) from 15 patients with hepatocellular carcinoma (HCC) and one with cholangiocarcinoma were plated into culture flask without disaggregation by trypsin-ethylenediamine tetra-acetic acid solution. Six patients with HCC and one patient with cholangiocarcinoma (7/16, 44%) had successful culture and the cancer cells at the 4th passage were continuously exposed to therapeutic ranges of epirubicin (0, 0.5, 1.0, 1.5, 2.0 µg/mL) with or without the combination of 2.5 µg/mL AmB for 24 h. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was applied to evaluate the effects of the drugs. A human HCC cell line (HA 22T/VGH) was studied for comparison. Results:, Addition of AmB showed no influence on epirubicin cytotoxicity in two patients (one partial resistant HCC and one epirubicin-sensitive cholangiocarcinoma; 25%), augmentation of the epirubicin cytotoxicity in two patients (one total resistant HCC, partial resistant HA 22T/VGH cell line and one epirubicin-sensitive HCC; 37.5%), and decrease of epirubicin cytotoxicity in the remaining three (one partial resistant and two epirubicin-sensitive HCC; 37.5%). Conclusions:, Amphotericin B has a discordant influence on epirubicin cytotoxicity in primary cultured hepatic malignant cells. Application of AmB in the systemic chemotherapy of primary hepatic malignancy should be limited to patients with positive AmB effect evaluated by an in vitro sensitivity test such as the present method. [source] Combination of a new composite biocampatible skin graft on the neodermis of artificial skin in an animal modelANZ JOURNAL OF SURGERY, Issue 5 2002Ping K. Lam Introduction: There have been very limited and inconsistent attempts at combining the cultured epidermal autograft (CEA) with the neodermis of artificial skin (Integra). The reasons for this remain unknown. The basement membrane proteins of conventional CEA sheets are easily damaged by the dispase treatment during the harvesting of the CEA from the culture flask. The damage of the basement membrane proteins may affect the anchorage of CEA onto the neodermis of Integra. A new Composite Biocompatible Skin Graft (CBSG) was recently developed. Methods: Composite biocompatible skin graft consists of autologous keratinocytes cultivated on a pliable hyaluronate-derived membrane (Laserskin) which has been pre-seeded with allogenic dermal fibroblasts. Basement membrane proteins of CBSG are protected from the dispase treatment because the keratinocytes are directly seeded onto Laserskin. The engraftment of CBSG was evaluated on 20 wounds of 10 rats. Integra was grafted on two freshly excised full-thickness wounds (3 cm in diameter) in the dorsum of each animal. A polypropylene ring was applied to each wound to prevent the migration of epithelium from the edges. Composite Biocompatible Skin Graft was used to cover the neodermis of Integra after the silicone membrane was removed 14,21 days postgrafting. Results: Fourteen (70%) of 20 skin biopsies taken at day 21 from the centre of the grafted wounds revealed regenerated epithelium. Conclusion: A feasible delivery system of cultured keratinocytes onto the neodermis of Integra is demonstrated in this animal experiment. [source] Exposure of human peripheral blood lymphocytes to electromagnetic fields associated with cellular phones leads to chromosomal instabilityBIOELECTROMAGNETICS, Issue 2 2003Maya Mashevich Abstract Whether exposure to radiation emitted from cellular phones poses a health hazard is at the focus of current debate. We have examined whether in vitro exposure of human peripheral blood lymphocytes (PBL) to continuous 830 MHz electromagnetic fields causes losses and gains of chromosomes (aneuploidy), a major "somatic mutation" leading to genomic instability and thereby to cancer. PBL were irradiated at different average absorption rates (SAR) in the range of 1.6,8.8 W/kg for 72 hr in an exposure system based on a parallel plate resonator at temperatures ranging from 34.5,37.5 °C. The averaged SAR and its distribution in the exposed tissue culture flask were determined by combining measurements and numerical analysis based on a finite element simulation code. A linear increase in chromosome 17 aneuploidy was observed as a function of the SAR value, demonstrating that this radiation has a genotoxic effect. The SAR dependent aneuploidy was accompanied by an abnormal mode of replication of the chromosome 17 region engaged in segregation (repetitive DNA arrays associated with the centromere), suggesting that epigenetic alterations are involved in the SAR dependent genetic toxicity. Control experiments (i.e., without any RF radiation) carried out in the temperature range of 34.5,38.5 °C showed that elevated temperature is not associated with either the genetic or epigenetic alterations observed following RF radiation,the increased levels of aneuploidy and the modification in replication of the centromeric DNA arrays. These findings indicate that the genotoxic effect of the electromagnetic radiation is elicited via a non-thermal pathway. Moreover, the fact that aneuploidy is a phenomenon known to increase the risk for cancer, should be taken into consideration in future evaluation of exposure guidelines. Bioelectromagnetics 24:82,90, 2003. © 2003 Wiley-Liss, Inc. [source] NF-,B DNA-binding activity after high peak power pulsed microwave (8.2 GHz) exposure of normal human monocytesBIOELECTROMAGNETICS, Issue 4 2002Mohan Natarajan Abstract The hypothesis investigated is that exposure of a mammalian cell to high peak power pulsed RF, at the frequency of 8.2 GHz, can result in the activation of an important eukaryotic transcriptional regulator, nuclear factor kappa B (NF-,B). This DNA-binding protein controls genes involved in long term cellular regulation. The selection of 8.2 GHz was based on the availability of a high peak power pulsed RF transmitter. In these studies, triplicate cultures of human monocytes (Mono Mac-6) were exposed to the pulsed wave radiation. The peak to average power ratio was 455:1 (2.2 ,s pulse width and pulse repetition rate of 1000 pulses/s). The average power density at the position of exposure was 50 W/m2, and the mean SAR at the bottom of the culture flask was 10.8,±,7.1 W/kg. The FDTD analysis indicated that 10% of the cells had an SAR of 22,29 W/kg. The cells were exposed continuously for 90 min at 37 °C, reincubated at this temperature, and harvested 4 h postexposure. The nuclear extracts were analyzed by electrophoretic mobility shift assay. The results showed a profound increase (3.6-fold) in the DNA binding activity of NF-,B in monocytes at 4 h after the pulsed RF exposure compared to sham irradiated controls. Competition experiments with cold NF-,B- specific oligonucleotides confirmed the specificity of the DNA binding activity. These results provide evidence that high peak power pulsed radiofrequency radiation can perturb the cell and initiate cell signaling pathways. However, at this point, we are not prepared to advocate that the cause is a nonthermal mechanism. Because of the broad distribution of SAR's in the flask, experiments need to be performed to determine if the changes observed are associated with cells exposed to high or low SARs. Bioelectromagnetics 23:271,277, 2002. © 2002 Wiley-Liss, Inc. [source] Mobilization of metals from uranium mine waste: the role of pyoverdines produced by Pseudomonas fluorescensGEOBIOLOGY, Issue 4 2010F. EDBERG Microorganisms produce chelating agents, such as siderophores and other ligands, which allow them to mobilize and scavenge essential elements from the environment when bioavailability is low. To better understand the effects of biologically mediated leaching of metals from mine waste, Pseudomonas fluorescens was cultivated in the presence of processed ore from the former uranium mine in Ranstad, southern Sweden. Light conditions, the concentration of the mineral source and oxygen availability were varied. The presence of ore in the culture flasks enhanced bacterial growth and raised the pH of the culture medium. Increasing the amount of ore or enhancing aeration of the medium further encouraged cell growth and pH rise. Bacteria mobilized Fe, Ni and Co from the ore. Fe-siderophore complexes were detected and estimated to be present at approximately 9 ,m. In the presence of bacteria and light, dissolved Fe and U concentrations were higher compared to dark conditions. Increasing the amount of ore resulted in higher dissolved Ni concentrations but lower dissolved Fe, most likely due to precipitate formation. Data from this study support siderophore production by bacteria that allowed mobilization of essential nutrients from the processed ore. However, the availability of potentially toxic metals like Ni and U may also be enhanced. Microbial-promoted mobilization could contribute to leaching of toxic metals in current and historic mining areas. This process should be considered during design and implementation of remediation projects where trace metals are of environmental concern. [source] Genetically Manipulated Human Skeletal Myoblast Cells for Cardiac TransplantationJOURNAL OF CARDIAC SURGERY, Issue 6 2002Kh H Haider Aim: Considering the promise of skeletal myoblast cell transplantation to improve cardiac function in myocardial myopathies, we aim in the present study to investigate the potential of human skeletal myoblast cells (HSMC) as a carrier for therapeutic genes for the heart muscle. Methods: Skeletal muscle sample is obtained from rectus femoris of the donor and is processed in the tissue culture to generate HSMC by a patented process of Cell Therapy Inc. The HSMC are grown in large 225 mm2 tissue culture flasks coated with collagen for enhanced cell adherence, using patented Super Medium (Cell Therapy Inc., Singapore) containing 10% fetal calf serum, to 80% confluence. The HSMC are passaged at regular time intervals of 48-72 hours to prevent in vitro differentiation. The HSMC thus obtained are transduced three times with retroviral vector carrying Lac-Z reporter gene before transplantation. The Lac-Z transduced HSMC are harvested by trypsinization, washed and re-suspended in serum free Super Medium. Ischemic Porcine model is created by clamping ameroid ring around left circumflex coronary artery in Yorkshire swine, four weeks prior to cell transplantation. For cell transplantation, the animal is anaesthetized, ventilated and heart is exposed by left thoracotomy. Fifteen injections (0.25 ml each) containing 300 million cells are injected in to the left ventricle endocardially under direct vision. For control animal, only culture medium without cells is injected. The animal is euthanized at pre-determined time, heart is explanted and processed for histological examination. The cryosectioning of the tissue and subsequent staining for Lac-Z expression and Hematoxylin-Eosin staining is carried out by standard methods. Results: The skeletal muscle samples processed by the patented method of Cell Therapy yield 85-90% pure HSMC. The preliminary data shows that repeated transductions of myoblast cells with retrovirus carrying Lac-Z yield highly efficient 70-75% Lac-Z positive HSMC population (Figure 1). Dye exclusion test using Trypan blue reveals >95% cell viability at the time of injection. Gross sections of the cardiac tissue stained positive for Lac-Z expression (Figure 2). Histological examination showed the presence of grafted myoblast cells expressing Lac-Z gene in the cardiac tissue (Figure 3). Conclusion: In the light of our preliminary results, we conclude that HSMC may prove to be excellent carriers of transgene for cardiac muscle cells which otherwise are refractory to ordinary gene transfection methods. The use of HSMC mediated gene delivery to cardiac muscle is safer as compared to direct injection of viral vectors in to the heart muscle. Furthermore, the grafted myoblast cells will additionally serve to strengthen the weakened heart muscle. Figure 1.Human Skeletal myoblasts transduced with Lac-Z carrying retrovirus and stained with x-gal. Figure 2.Gross sections of heart muscle stained for Lac-Z expression. Figure 3.X-gal stained porcine heart muscle counter-stained with Eosin. The heart was explanted 6 weeks after transplantation of Lac-Z stained human myoblasts. The arrow shows Lac-Z expressing myoblast cells. [source] A BATCH CULTURE METHOD FOR MICROALGAE AND CYANOBACTERIA WITH CO2 SUPPLY THROUGH POLYETHYLENE MEMBRANES,JOURNAL OF PHYCOLOGY, Issue 4 2010Yvonne Pörs A new method for CO2 supply to photoautotrophic organisms was developed, and its applicability for measuring specific growth rates in shaken batch cultures of cyanobacteria and unicellular algae was shown. Small bags containing a concentrated carbonate buffer with a CO2 partial pressure of 32 mbar were prepared from a thin foil of low density polyethylene (LDPE). These bags were inserted as CO2 reservoirs (CRs) into polystyrene culture flasks with gas-permeable screw caps, which were suitable to photometric growth measurement. CO2 was released directly into the medium with membrane-controlled kinetics. The CRs were not depleted within 1 week, although the atmosphere in the culture vessel exchanged rapidly with the ambient air. Rates of initial growth and final densities of the cultures of six different unicellular algal species and one cyanobacterium were markedly increased by diffusive CO2 supply from the CR. In the presence of a CR, growth was exponential during the first 2 d in all cultures studied. The method described allowed a high number of measurements of specific growth rates with relatively simple experimental setup. [source] | |||||||||||||