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1

Cell Culture Assay for Human Noroviruses [response  

SciTech Connect

We appreciate the comments provided by Leung et al., in response to our recently published article “In Vitro Cell Culture Infectivity Assay for Human Noroviruses” by Straub et al. (1). The specific aim of our project was to develop an in vitro cell culture infectivity assay for human noroviruses (hNoV) to enhance risk assessments when they are detected in water supplies. Reverse transcription (RT) qualitative or quantitative PCR are the primary assays for waterborne NoV monitoring. However, these assays cannot distinguish between infectious vs. non-infectious virions. When hNoV is detected in water supplies, information provided by our infectivity assay will significantly improve risk assessment models and protect human health, regardless of whether we are propagating NoV. Indeed, in vitro cell culture infectivity assays for the waterborne pathogen Cryptosporidium parvum that supplement approved fluorescent microscopy assays, do not result in amplification of the environmentally resistant hard-walled oocysts (2). However, identification of life cycle stages in cell culture provides evidence of infectious oocysts in a water supply. Nonetheless, Leung et al.’s assertion regarding the suitability of our method for the in vitro propagation of high titers of NoV is valid for the medical research community. In this case, well-characterized challenge pools of virus would be useful for developing and testing diagnostics, therapeutics, and vaccines. As further validation of our published findings, we have now optimized RT quantitative PCR to assess the level of viral production in cell culture, where we are indeed finding significant increases in viral titer. The magnitude and time course of these increases is dependent on both virus strain and multiplicity of infection. We are currently preparing a manuscript that will discuss these findings in greater detail, and the implications this may have for creating viral challenge pools

Straub, Tim M.; Honer Zu Bentrup, Kerstin; Orosz Coghlan, Patricia; Dohnalkova, Alice; Mayer, Brooke K.; Bartholomew, Rachel A.; Valdez, Catherine O.; Bruckner-Lea, Cindy J.; Gerba, Charles P.; Abbaszadegan, Morteza A.; Nickerson, Cheryl A.

2007-07-01

2

Evaluation of viability assays for anthocyanins in cultured cells.  

PubMed

The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay is a widely accepted cytotoxicity assay which can produce inaccurate results due to possible interference with the antioxidant property of anthocyanins. Alternative methods to the MTT assay, such as BrdU (DNA-based) and CellTiter-Glo (ATP-based) assays were evaluated to assess anthocyanin cytotoxicity, derived from blackberry in LNCaP, MCF-7 and MDA-MB-453 cell lines. The standard cell counting method was the reference assay. Greater correlation of cell viability values following anthocyanin exposure was obtained from multiple cell lines with the alternative assays when compared with cell counting. MTT and cell counting results were not always correlated, albeit this was a function of cell type. In particular, poor correlations between cell counting and MTT procedures used to assess cytotoxicity of anthocyanins were observed in the MDA-MB-453 cell lines. Comparison of cytotoxicity derived from alternative assays and the MTT assays with the cell counting method was dependent on the assay procedure and the cell type. The LC(50) of blackberry crude extract ranged from 0.4 to 9.4 mg/mL between assays and across all cell lines, whereas a semi-purified anthocyanin extract was not cytotoxic. Cytotoxicity evaluation of polyphenolic-rich extracts using BrdU and CellTiter-Glo assays as alternatives to the MTT method is recommended. PMID:18435529

Elisia, Ingrid; Popovich, David G; Hu, Chun; Kitts, David D

3

A cell culture assay for the detection of cardiotoxicity  

SciTech Connect

An important step in minimizing the number of animal experiments in medical research is the study of in vitro model systems. The authors propose the use of shock protein formation, which is a cellular response to cell-damaging stress as an assay to monitor cardiotoxicity. Isolated and cultured cardiac myocytes were prepared by a trypsin digestion method from 18-day-old fetal mice. These cells respond to typical substances inducing shock protein formation in other cellular systems as well as to known cardiotoxins with the de novo synthesis of shock proteins. Pharmaceuticals relevant in transplant medicine were tested for possible cardiotoxic effects: Cyclosporine A evokes shock protein formation at subtherapeutic concentrations. Azathioprine and methyl-prednisolone exert the same effect but at concentration ranges highly above the therapeutic level. The ability to induce shock protein synthesis obviously seems to be restricted to toxic drugs. The data presented demonstrate that the proposed in vitro model system for cardiotoxicity is animal saving and sensitive.

Loew-Friedrich, Iv.; von Bredow, F.; Schoeppe, W. (Department of Nephrology, Hospital of the Johann Wolfgang Goethe-University, Frankfurt am Main (Germany))

1991-04-01

4

A cell culture assay for the detection of cardiotoxicity.  

PubMed

An important step in minimizing the number of animal experiments in medical research is the study of in vitro model systems. We propose the use of "shock protein" formation, which is a cellular response to cell-damaging stress as an assay to monitor cardiotoxicity. Isolated and cultured cardiac myocytes were prepared by a trypsin digestion method from 18-day-old fetal mice. These cells respond to typical substances inducing "shock protein" formation in other cellular systems as well as to known cardiotoxins with the de novo synthesis of "shock proteins." Pharmaceuticals relevant in transplant medicine were tested for possible cardiotoxic effects: Cyclosporine A evokes "shock protein" formation at subtherapeutic concentrations. Azathioprine and methyl-prednisolone exert the same effect but at concentration ranges highly above the therapeutic level. The ability to induce "shock protein" synthesis obviously seems to be restricted to toxic drugs. The data presented demonstrate that the proposed in vitro model system for cardiotoxicity is animal saving and sensitive. PMID:1712416

Löw-Friedrich, I; von Bredow, F; Schoeppe, W

1991-04-01

5

In vitro Assay for Dermatotoxicity Using Cultured Human Epidermal Cells.  

National Technical Information Service (NTIS)

Since cultures of human epidermal cells may serve as a model for the living part of the epidermis, the suitability of this culture system in assessing skin irritancy has been studied. Five chemicals with well known dermatotoxic actions have been examined ...

M. A. E. Mol O. L. Wolthuis

1987-01-01

6

In Vitro Cell Culture Infectivity Assay for Human Noroviruses  

PubMed Central

Human noroviruses cause severe, self-limiting gastroenteritis that typically lasts 24–48 hours. Because of the lack of suitable tissue culture or animal models, the true nature of norovirus pathogenesis remains unknown. We show that noroviruses can infect and replicate in a 3-dimensional (3-D), organoid model of human small intestinal epithelium. Cells grown on porous collage-coated beads under fluid shear conditions in rotating wall vessel bioreactors differentiate into 3-D architectures resembling both the morphologic and physiologic function of in vivo tissues. Microscopy, PCR, and fluorescent in situ hybridization provided evidence of norovirus infection. Cytopathic effect and norovirus RNA were detected at each of the 5 cell passages for genogroup I and II viruses. Our results demonstrate that the highly differentiated 3-D cell culture model can support the natural growth of human noroviruses, whereas previous attempts that used differentiated monolayer cultures failed.

Honer zu Bentrup, Kerstin; Coghlan, Patricia Orosz; Dohnalkova, Alice; Mayer, Brooke K.; Bartholomew, Rachel A.; Valdez, Catherine O.; Bruckner-Lea, Cynthia J.; Gerba, Charles P.; Abbaszadegan, Morteza A.; Nickerson, Cheryl A.

2007-01-01

7

A simple and sensitive assay for mycoplasma detection in mammalian cell culture  

PubMed Central

Mycoplasma contamination in mammalian cell cultures is often overlooked yet is a serious issue which can induce a myriad of cellular changes leading to false interpretation of experimental results. Here we present a simple and sensitive assay to monitor mycoplasma contamination (mycosensor) based on degradation of the Gaussia luciferase reporter in the conditioned medium of cells. This assay proved to be more sensitive as compared to a commercially-available bioluminescent assay in detecting mycoplasma contamination in seven different cell lines. The Gaussia luciferase mycosensor assay provides an easy tool to monitor mammalian cells contaminants in a high-throughput fashion.

Degeling, M. Hannah; Maguire, Casey A.; Bovenberg, M. Sarah S.; Tannous, Bakhos A.

2012-01-01

8

Induced cell death of preimplantation mouse embryos cultured in vitro evaluated by comet assay  

Microsoft Academic Search

The occurrence of apoptosis in mouse preimplantation embryos was analyzed using DNA staining (Hoechst 33342, PI) for the visualization of nuclear changes and by the comet assay, a single-cell gel electrophoresis assay, modified for the analysis of blastocysts. Mouse preimplantation embryos isolated 56h after superovulation were cultured in vitro for 64h. Apoptosis was induced by treatment with camptothecin and actinomycin

Dušan Fabian; Pavol Rehák; So?a Czikková; Gabika Il’ková; Vladim??r Baran; Juraj Koppel

2003-01-01

9

Human L1 retrotransposition: insights and peculiarities learned from a cultured cell retrotransposition assay  

Microsoft Academic Search

Long Interspersed Nuclear Elements (L1s or LINEs) are the most abundant retrotransposons in the human genome, and they comprise\\u000a approximately 17% of DNA. L1 retrotransposition can be mutagenic, and deleterious insertions both in the germ-line and in\\u000a somatic cells have resulted in disease. Recently, an assay was developed to monitor L1 retrotransposition in cultured human\\u000a cells. This assay, for the

John V. Moran

1999-01-01

10

A Reliable Tool to Determine Cell Viability in Complex 3-D Culture: The Acid Phosphatase Assay  

Microsoft Academic Search

Cell-based assays are more complex than cell-free test systems but still reflect a highly artificial cellular environment. Incorporation of organotypic 3-dimensional (3-D) culture systems into mainstream drug development processes is increasingly discussed but severely limited by complex methodological requirements. The objective of this study was to explore a panel of standard assays to provide an easy-handling, standardized protocol for rapid

Juergen Friedrich; Wolfgang Eder; Juana Castaneda; Markus Doss; Elisabeth Huber; Reinhard Ebner; Leoni A. Kunz-Schughart

2007-01-01

11

Development of an Assay for the Measurement of the Surfactant Pluronic F-68 in Mammalian Cell Culture Medium  

Microsoft Academic Search

A colorimetric assay is described for the measurement of Pluronic F-68 in animal cell culture medium. The assay is based on the formation of a complex with cobalt thiocyanate as previously developed for the measurement of Pluronic in liver tissue. To adapt the assay for the lower detection levels required in cell culture medium, the absorbance of the complex was

Hazem Ghebeh; Anita Handa-Corrigan; Michael Butler

1998-01-01

12

Cell culture assays to evaluate bacterial toxicity and virulence.  

PubMed

Helicobacter pylori CagA and VacA are two critical virulence factors that modulate disease severity in the infected host. The following chapter outlines methods employed to study the effects of these virulence factors on several key signaling pathways in epithelial cells. PMID:23015494

Raju, Deepa; Rizzuti, David; Jones, Nicola L

2012-01-01

13

Mechanistic features of CAGCTG repeat contractions in cultured cells revealed by a novel genetic assay  

Microsoft Academic Search

Trinucleotide repeats (TNRs) undergo high frequency mutagenesis to cause at least 15 neurodegenerative diseases. To understand better the molecular mech- anisms of TNR instability in cultured cells, a new gen- etic assay was created using a shuttle vector. The shuttle vector contains a promoter-TNR-reporter gene construct whose expression is dependent on TNR length. The vector harbors the SV40 ori and

Richard Pelletier; Brian T. Farrell; Juan JoseMiret; Robert S. Lahue

14

COMPARATIVE TOXICITIES OF DIFFERENT FORMS OF ASBESTOS IN A CELL CULTURE ASSAY  

EPA Science Inventory

Three forms of Union Internationale Contre le Cancer (UICC) asbestos, amosite, crocidolite, and chrysotile, were assayed for their cytotoxicity (inhibition of colony formation) in cell culture. Using embryonic human intestine-derived (I-407) and adult rat liver-derived (ARL-6) ep...

15

Gaussia luciferase-based Mycoplasma detection assay in Mammalian cell culture.  

PubMed

Mycoplasma contamination in mammalian cell culture is a common problem with serious consequences on experimental data, and yet many laboratories fail to perform regular testing. In this chapter, we describe a simple and sensitive mycoplasma detection assay based on the bioluminescent properties of the Gaussia luciferase reporter. PMID:24166367

Degeling, M Hannah; Bovenberg, M Sarah S; Tannous, Marie; Tannous, Bakhos A

2014-01-01

16

Quantitative assay for binding of Bradyrhizobium japonicum to cultured soybean cells.  

PubMed Central

Incubation of Bradyrhizobium japonicum with the cultured soybean cell line SB-1 resulted in the adhesion of the bacteria to the plant cells. An antiserum was raised against B. japonicum, and the 125I-labeled immunoglobulin fraction was used to quantitate the number of bacteria bound to the soybean cells. The measurement of 125I-labeled antibody binding correlated well with parallel assays by microscopic observation. Using this quantitation, we have optimized the parameters of the assay in terms of time course, ratio of B. japonicum to SB-1 cells, and pH. We then explored the effects of saccharides, NaCl, EDTA, and culture age of the bacteria and SB-1 cells on B. japonicum binding under these optimal assay conditions. The results showed good correlation between conditions that govern B. japonicum binding to SB-1 cells in culture and those that regulate B. japonicum-induced nodulation in legume roots. Together, they suggest that this binding event may be important in controlling host specificity. Images

Ho, S C; Ye, W Z; Schindler, M; Wang, J L

1988-01-01

17

Real-time impedance assay to follow the invasive activities of metastatic cells in culture.  

PubMed

Here we present research detecting the invasive activities of metastatic cells in vitro using electric cell-substrate impedance sensing (ECIS). The assay is based on previous microscopic observations, where metastatic cells added over established endothelial cell layers were observed to attach to and invade the cell layer. Human umbilical vein endothelial cells (HUVECs) werefirst grown to confluence on small gold electrodes. The impedance of these electrodes was followed after the addition of suspensions of different sublines of the Dunning murine prostatic adenocarcinoma series (G, AT1, AT2, AT3, ML, and MLL). For highly metastatic sublines, within an hour after being challenged, the impedance of the confluent HUVEC layer was substantially reduced. The effect of the weakly metastatic sublines was less pronounced, and the extent and the rate of this drop in impedance could be correlated with the metastatic potential of each of six sublines tested. The real-time assay is effective in both normal and low (1%) serum concentrations, and the detected activity requires the presence of viable transformed cells. In addition to the murine cell lines, similar behavior was observed using four established human prostatic cancer lines (DU145, PC3, TSU, and PPC1). These results suggest that this ECIS-based assay might be used with primary human cultures to establish the metastatic abilities of cells isolated from biopsies. PMID:12398193

Keese, Charles R; Bhawe, Kaumudi; Wegener, Joachim; Giaever, Ivar

2002-10-01

18

Measurement of cytotoxicity by ATP-based luminescence assay in primary cell cultures and cell lines  

Microsoft Academic Search

Drug discovery and toxicological safety testing share a need for dependable in vitro cellular toxicity tests. Ideally such tests should be objective, quantitative, reproducible and able to lend themselves to automation. A number of assays fulfil these criteria well, but recently it has become clear that the molecular phenotype of the cell tested and the complex interplay between different cell

I. A. Cree; P. E. Andreotti

1997-01-01

19

Development of an ultrasensitive in vitro assay to monitor growth of primary cell cultures with reduced mitotic activity  

Microsoft Academic Search

Primary cell cultures, such as isolated epithelial cells, neuronal cells, or hepatocytes are characterized by a very low mitotic activity. Monitoring of small changes in cell numbers requires staining with a DNA-specific dye with an extremely high sensitivity and a low inter- and intraassay variability. For this purpose, an ultrasensitive in vitro assay has been developed based on the fluorescent

Roman A. Blaheta; Bernd Kronenberger; Dirk Woitaschek; Stephan Weber; Martin Scholz; Horst Schuldes; Albrecht Encke; Bernd H. Markus

1998-01-01

20

A novel time resolved fluorometric assay of anoikis using Europium-labelled Annexin V in cultured adherent cells  

Microsoft Academic Search

Background: Adherent cells undergo apoptosis when detached from their home ground, a process called anoikis (homelessness).Methods: We developed a new and sensitive method to analyse apoptosis and anoikis of adherent cell types using a time resolved fluorometric assay with Europium-labelled Annexin V. Anoikis was induced with tumor necrosis factor- \\/cycloheximide and three cell fractions of the cell cultures were prepared

P. Engbers-Buijtenhuijs; M. Kamphuis; G. van der Sluijs Veer; C. Haanen; A. A. Poot; J. Feijen; I. Vermes

2005-01-01

21

Rapid detection of polyomavirus BK by a shell vial cell culture assay.  

PubMed Central

Polyomavirus BK (BKV) causes asymptomatic latent infection in the human host that is reactivated during periods of immune suppression. Detection by conventional tube cell culture is difficult and time consuming because BKV exhibits slow growth with late (14 to 28 days) and subtle cytopathic effects. We developed a shell vial cell culture assay (SVA) using a cross-reactive monoclonal antibody to the T antigen of simian virus 40 to detect BKV rapidly by indirect immunofluorescence. Nuclear fluorescence was seen in BKV-infected cells as early as 16 h postinoculation; 6 to 28 times more foci were present at 36 h postinoculation. Human embryonic kidney cells infected with BKV produced 7 to 42 times more fluorescent foci than MRC-5 or rhabdomyosarcoma cells did. Centrifugation enhanced the infectivity of BKV in the SVA. To define the clinical utility of SVA, urine specimens from organ transplant patients were tested. Of 27 patients, 4 (15%) were found to be positive by SVA. SVA offers a simple and rapid method for detection of BKV that can be of use in clinical studies of this virus. Images

Marshall, W F; Telenti, A; Proper, J; Aksamit, A J; Smith, T F

1990-01-01

22

Cytotoxicity of mycotoxins evaluated by the MTT-cell culture assay.  

PubMed

The application of a modified colorimetric bioassay for the evaluation of the biological effects of mycotoxins is reported. Using three different monolayer cell lines (swine kidney, Madin Darby canine kidney, HeLa) the influence of nine different mycotoxins on the cellular methylthiazoltetrazolium (MTT)-cleavage activity was evaluated. The yellow tetrazolium salt MTT is converted by mitochondrial dehydrogenases of metabolically active cells to an insoluble purple formazan product, which was then solubilized with dimethylsulfoxide. The optical density of this homogeneous solution was suitable for a precise spectrophotometric measurement by a plate reader at a wavelength of 510 nm. Nine mycotoxins were simultaneously tested in all three cell lines, from which the swine kidney cell line proved to be the most sensitive. The effects of additional 35 mycotoxins were therefore tested using swine kidney monolayers as target cells. A total of 28 toxins of the 44 mycotoxins tested proved to be cytotoxic in the MTT-bioassay. Most of them belong to the group of trichothecene mycotoxins. Concentrations ranged between 0.01 micrograms and 100 micrograms/ml of cell culture medium. The MTT cleavage assay was found to be a quick (24 hours) and easy to perform system for the evaluation of the biological activity of many different mycotoxins and may also provide a useful tool for the testing of a large variety of sample materials. PMID:7739730

Hanelt, M; Gareis, M; Kollarczik, B

1994-12-01

23

RT-PCR and cell culture infectivity assay to detect enteroviruses during drinking water treatment processes.  

PubMed

In this study, 62 water samples were collected from two water treatment plants (WTPs) in Suez Canal cities (Port Said and Ismaillia) and one plant in Cairo (Giza WTP) in addition to the beginning of the two Nile river branches (Rosetta and Damietta). Viruses were concentrated by adsorption-elution ethod sing 142 mm-diameter nitrocellulose membrane of 0.45 microm pore size and eluted with 3% beef extract at pH 9.5. The concentrated samples were inoculated for 3 successive passages in three cell culture types (Vero, BGM and RD). Enterovirus RNAs in CPE-induced samples were extracted by guanidinium thiocyanate/ phenol/chloroform and heat shock methods and detected by RT-PCR and neutralization test. The results showed that eight samples [14.5% (8/62)] contained enteroviruses most of them were polioviruses [87.5% (7/8)] and coxsackievirus type B2 [12.5% (1/8)]. The three cell cultures were of the same sensitivity to detect the isolated viruses. Also, RT-PCR followed by neutralization assay facilitates and accelerate the results. The guanidinium thiocyanate extraction method was more sensitive than heat shock method. The results turned our attention to review our technology of water treatment and disinfection step in addition to the selection of suitable intake for the drinking water treatment plants. PMID:17219867

Ali, M A; El-Esnawy, N A; Shoaeb, A R; Ibraheim, M; El-Hawaary, S E

1999-01-01

24

Intrinsic migratory properties of cultured Schwann cells based on single-cell migration assay.  

PubMed

The migration of Schwann cells is critical for development of peripheral nervous system and is essential for regeneration and remyelination after nerve injury. Although several factors have been identified to regulate Schwann cell migration, intrinsic migratory properties of Schwann cells remain elusive. In this study, based on time-lapse imaging of single isolated Schwann cells, we examined the intrinsic migratory properties of Schwann cells and the molecular cytoskeletal machinery of soma translocation during migration. We found that cultured Schwann cells displayed three motile phenotypes, which could transform into each other spontaneously during their migration. Local disruption of F-actin polymerization at leading front by a Cytochalasin D or Latrunculin A gradient induced collapse of leading front, and then inhibited soma translocation. Moreover, in migrating Schwann cells, myosin II activity displayed a polarized distribution, with the leading process exhibiting higher expression than the soma and trailing process. Decreasing this front-to-rear difference of myosin II activity by frontal application of a ML-7 or BDM (myosin II inhibitors) gradient induced the collapse of leading front and reversed soma translocation, whereas, increasing this front-to-rear difference of myosin II activity by rear application of a ML-7 or BDM gradient or frontal application of a Caly (myosin II activator) gradient accelerated soma translocation. Taken together, these results suggest that during migration, Schwann cells display malleable motile phenotypes and the extension of leading front dependent on F-actin polymerization pulls soma forward translocation mediated by myosin II activity. PMID:23251634

Wang, Ying; Teng, Hong-Lin; Huang, Zhi-hui

2012-12-14

25

Intrinsic Migratory Properties of Cultured Schwann Cells Based on Single-Cell Migration Assay  

PubMed Central

The migration of Schwann cells is critical for development of peripheral nervous system and is essential for regeneration and remyelination after nerve injury. Although several factors have been identified to regulate Schwann cell migration, intrinsic migratory properties of Schwann cells remain elusive. In this study, based on time-lapse imaging of single isolated Schwann cells, we examined the intrinsic migratory properties of Schwann cells and the molecular cytoskeletal machinery of soma translocation during migration. We found that cultured Schwann cells displayed three motile phenotypes, which could transform into each other spontaneously during their migration. Local disruption of F-actin polymerization at leading front by a Cytochalasin D or Latrunculin A gradient induced collapse of leading front, and then inhibited soma translocation. Moreover, in migrating Schwann cells, myosin II activity displayed a polarized distribution, with the leading process exhibiting higher expression than the soma and trailing process. Decreasing this front-to-rear difference of myosin II activity by frontal application of a ML-7 or BDM (myosin II inhibitors) gradient induced the collapse of leading front and reversed soma translocation, whereas, increasing this front-to-rear difference of myosin II activity by rear application of a ML-7 or BDM gradient or frontal application of a Caly (myosin II activator) gradient accelerated soma translocation. Taken together, these results suggest that during migration, Schwann cells display malleable motile phenotypes and the extension of leading front dependent on F-actin polymerization pulls soma forward translocation mediated by myosin II activity.

Huang, Zhi-hui

2012-01-01

26

A microtiter trypan blue absorbance assay for the quantitative determination of excitotoxic neuronal injury in cell culture.  

PubMed

An automated method for the determination of neuronal cell death using trypan blue is described. Following various excitotoxic insults, murine mixed cortical cell cultures are stained with trypan blue (0.05%; 15 min), followed by SDS (1%) lysis. The absorbance of the dye is measured spectrophotometrically at 590 nm using a microtiter plate reader. When compared to the biochemical lactate dehydrogenase assay, no statistical difference in the calculated levels of excitotoxic neuronal cell death was noted between the assays in any given paradigm. This method is fast and reliable. It eliminates the need for cell counting, thus allowing for high volume sample analysis with a minimum of sample error. Utility of this trypan blue absorbance spectrophotometric assay is likely to extend beyond the study of excitotoxic neuronal injury and should complement existing methods for measuring neuronal viability and cytotoxicity in cell culture. PMID:11040379

Uliasz, T F; Hewett, S J

2000-07-31

27

Toxicity of folic acid analogs in cultured human cells: a microtiter assay for the analysis of drug competition.  

PubMed Central

We have used a microtiter assay to study the toxicity of various folate analogs in a series of cultured human cell lines that exhibit different degrees of resistance to methotrexate, an inhibitor of dihydrofolate reductase. These cells retain their sensitivity to the lipophilic antifolate BW301U despite the amplification of dihydrofolate reductase genes. Because the cell lines under investigation grow very slowly and have poor plating efficiencies in unconditioned medium, an assay was developed that relies on cell proliferation rather than colony formation as a measure of toxicity. This approach is easily generalized to provide a rapid and inexpensive assay of drug competition. Two-dimensional studies indicate that methotrexate and BW301U show differences in patterns of toxicity, competition, and rescue by folinic acid, suggesting that the two drugs act on different targets. Further applications of the microtiter assay to the analysis of multidrug interactions are discussed. Images

Roos, D S; Schimke, R T

1987-01-01

28

An assay for measuring specific adhesion of an Escherichia coli strain to tissue culture cells  

Microsoft Academic Search

Escherichia coli SS142 has been found to adhere specifically to the human epithelioid tissue culture cell line Intestine 407, but not to other tissue culture cells. This paper describes an accurate, reproducible and objective method of assessing the rate of adhesion of radiolabelled bacteria to these cellular monolayers. Adhesion was found to be linear with time for 60 min and

K. Vosbeck; U. Huber

1982-01-01

29

An improved system for exposure of cultured mammalian cells to gaseous compounds in the chromosomal aberration assay.  

PubMed

A gas exposure system using rotating vessels was improved for exposure of cultured mammalian cells to gaseous compounds in the chromosomal aberration assay. This system was composed of 12 square culture vessels, a device for preparation of air containing test gas, and positive and negative control gases at target concentrations and for supplying these gases to the culture vessels, and a roller apparatus in an incubator. Chinese hamster lung cells (CHL/IU) were grown on one side of the inner surface of the square culture vessel in the MEM medium. Immediately prior to exposure, the medium was changed to the modified MEM. Air in the culture vessel was replaced with air containing test gas, positive or negative control gas. Then, the culture vessels were rotated at 1.0 rpm. The monolayered culture cells were exposed to test gas during about 3/4 rotation at upper positions and alternatively immersed into the culture medium during about 1/4 rotation at lower positions. This system allowed the chromosomal aberration assay simultaneously at least at three different concentrations of a test gas together with positive and negative control gases with and without metabolic activations, and duplicate culture at each exposure concentration. Seven gaseous compounds, 1,3-butadiene, chlorodifluoromethane, ethyl chloride, methyl bromide, methyl chloride, propyne, and vinyl chloride, none of which has been tested to date, were tested on CHL/IU for the chromosomal aberration assay using this gas exposure system. All the compounds except chlorodifluoromethane showed positive responses of the structural chromosomal aberrations, whereas polyploidy was not induced by any of these gases. This improved gas exposure system proved to be useful for detecting chromosomal aberrations of gaseous compounds. PMID:18342567

Asakura, Masumi; Sasaki, Toshiaki; Sugiyama, Toshie; Arito, Heihachiro; Fukushima, Shoji; Matsushima, Taijiro

2008-02-01

30

A colorimetric assay for the measurement of -glucose consumption by cultured cells  

Microsoft Academic Search

A colorimetric method is described for measuring glucose consumption by tissue culture cells. This proce- dure, which utilizes the coupled activities of glucose ox- idase and horseradish peroxidase, is insensitive to the spectral interferences caused by the phenol red and sera present in most tissue culture media. The spectral properties (absorbance maxima and apparent absorp- tion coefficients) and stability of

Diane A. Blake; Natalie V. McLean

1989-01-01

31

Cultures of bovine cornea and conjunctiva epithelial cells for use in a bacterial adherence assay  

Microsoft Academic Search

Summary Methods to culture bovine cornea and conjunctiva epithelial cells in suspension are described. Fetal, newborn, and adult corneas and conjunctivas are obtained from animals killed just before culture, or from packing-plant sources. Excised corneas are dissected mid-stroma, and the anterior stroma and attached epithelial layer are affixed onto plastic flasks. Dissected conjunctival mucosa fragments are likewise attached. Growth medium

Ricardo F. Rosenbusch

1988-01-01

32

Sensitive assay of RNA interference in Drosophila and Chinese hamster cultured cells using firefly luciferase gene as target  

Microsoft Academic Search

A sensitive cellular assay system for RNA interference was developed using the firefly luciferase gene as target. RNA interference was noted not only in Drosophila cultured cells but Chinese hamster cells (CHO-K1) as well, although double-stranded RNA required for the latter was 2500 times more than for the former. Cognate double-stranded RNA as short as 38 bp was found to

Kumiko Ui-Tei; Shuhei Zenno; Yuhei Miyata; Kaoru Saigo

2000-01-01

33

DNA damage and repair measurements from cryopreserved lymphocytes without cell culture--a reproducible assay for intervention studies.  

PubMed

Single-cell gel electrophoresis (the Comet assay) can be used to measure DNA damage and DNA repair capacity (DRC). However, to test DRC of cryopreserved lymphocytes, published methods include steps for cell culturing and phytohemagglutinin stimulation, which may limit use of this assay in intervention studies. We developed a modified Comet assay protocol that allows us to measure DRC from cryopreserved lymphocytes without these in vitro manipulations. Assay reproducibility was evaluated by performing the assay six times on different dates using six aliquots from one blood draw of one individual. The interindividual variation was assessed by performing the assay using one aliquot from six individuals. When gamma-irradiation was used as the mutagen, intra-assay coefficients of variation (CVs.) for baseline DNA damage, damage after gamma-irradiation exposure, and DRC--measured as tail moment--were 8, 31, and 10%, respectively. Interindividual CVs. were higher. When H(2)O(2) was used as the mutagen, intra-assay CVs. for damage measurements were lower for a protocol modification that included damage and repair at 37 degrees C (CVs. ranging from 8 to 35%) than for the more standard 4 degrees C protocol. Analyzing moment arm--the average distance of DNA migration within the tail--yielded similar results. DNA repair was successfully detected in each experiment. Comparing freshly isolated lymphocytes to cryopreserved lymphocytes from the same individuals' blood draw indicated that DRC was highly correlated when determined using moment arm values. This modified protocol extends the use of the Comet assay to measuring DRC in intervention studies (e.g., dietary interventions) in that it assesses cellular response after cryopreservation without cell culture or other extensive manipulation. PMID:16673412

Chang, Jyh-Lurn; Chen, Gang; Lampe, Johanna W; Ulrich, Cornelia M

2006-08-01

34

A simple quantitative assay for the killing of in vitro culture cells by Ehrlichia canis infection  

Microsoft Academic Search

A simple colorimetric assay, on the basis of bioreduction of the substrate XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt) by dehydrogenases of actively metabolizing mammalian cells, was assessed for measurement of in vitro killing of canine macrophage-like cells by Ehrlichia canis infection. Formation of a highly colored, water soluble formazan which resulted from bioreduction by the test cells was significantly enhanced by phenazine

Jianneng Ma; Maria W. Nicholl

1996-01-01

35

A nonradioisotope, enzymatic assay for 2-deoxyglucose uptake in L6 skeletal muscle cells cultured in a 96-well microplate.  

PubMed

A nonradioisotope, 96-well-microplate assay to evaluate glucose uptake activity in cultured cells has been developed. 2-Deoxyglucose (2DG) was detected by measuring a potent fluorophore, resorufin, generated after incubation with a single assay solution containing hexokinase, adenosine 5'-triphosphate, glucose 6-phosphate dehydrogenase, beta-nicotineamide adenine dinucleotide phosphate, diaphorase, and resazurin. This amplifying detection system could detect the fluorescence intensity induced by uptake of 2DG into L6 skeletal muscle cells, even at the level of cells cultivated in individual wells in a 96-well microplate. Using this assay system, the effects of insulin, cytochalasin B (hexose uptake inhibitor), LY294002 (inhibitor of glucose transporter translocation), and pioglitazone hydrochloride (insulin-sensitizing agent) on 2DG uptake into L6 myotubes could be assessed clearly. Therefore, our simple method may be useful for in vitro high-throughput screening and for evaluating regulators of glucose uptake. PMID:16442489

Yamamoto, Norio; Sato, Takuya; Kawasaki, Kengo; Murosaki, Shinji; Yamamoto, Yoshihiro

2006-01-13

36

Immunological assays for chemokine detection in in-vitro culture of CNS cells  

Microsoft Academic Search

Herein we review the various methods currently in use for determining the expression of chemokines by CNS cells in vitro.\\u000a Chemokine detection assays are used in conjuction with one another to provide a comprehensive, biologically relevant assessment\\u000a of the chemokines which is necessary for correct data interpretation of a specific observed biological effect. The methods\\u000a described include bioassays for soluble

Supriya D. Mahajan; Stanley A. Schwartz; Madhavan P. N. Nair

2003-01-01

37

Multicenter Comparison of the Digene Hybrid Capture CMV DNA Assay (Version 2.0), the pp65 Antigenemia Assay, and Cell Culture for Detection of Cytomegalovirus Viremia  

Microsoft Academic Search

We compared the Digene Hybrid Capture CMV DNA Assay version 2.0, the pp65 antigenemia assay, traditional tube culture, and shell vial culture for the detection of cytomegalovirus (CMV) viremia in several patient populations at three centers. Of 561 blood specimens collected from 402 patients, complete clinical and laboratory data were available for 489. Using consensus definitions for true positives and

TONY MAZZULLI; LAWRENCE W. DREW; BELINDA YEN-LIEBERMAN; DRAGANA JEKIC-MCMULLEN; DEBRA J. KOHN; CARLOS ISADA; GEORGE MOUSSA; ROBERT CHUA; SHARON WALMSLEY

38

Ovarian carcinoma cells in culture: assessment of drug sensitivity by clonogenic assay.  

PubMed Central

Ovarian tumours were cultured by clonogenic assay and drug sensitivity profiles obtained for cis-platinum, adriamycin and phosphoramide mustard. Results were correlated with clinical outcome. Two hundred samples were received from 106 patients and 115/167 with malignant cytology (69%) were cultured successfully. Drug results were obtained on 71 samples and in untreated patients 60% of samples (48% of patients) were markedly sensitive to cis-platinum and 87% of samples (76% of patients) were sensitive to adriamycin. Eighty-one percent of cases sensitive to adriamycin were also sensitive to cis-platinum. Two of 7 samples were sensitive to phosphoramide mustard; the remainder were resistant. Eighty percent of samples from treated patients were resistant in vitro to drugs already received. Seventy-one samples from 57 patients were suitable for drug study. Forty-eight patients received chemotherapy, but only 23 received the drugs tested. Clinical correlations showed that in vitro sensitivity to cis-platinum and adriamycin was related to a good clinical response. No correlations were observed between cis-platinum and adriamycin resistance in vitro and clinical outcome. Unexpected relationships, however, were observed between cis-platinum resistance and failure to respond to other alkylating agents received singly. No such relationship has been demonstrated for adriamycin.

Simmonds, A. P.; McDonald, E. C.

1984-01-01

39

Bioluminescent high-throughput assay for the bacteria adherence to the tissue culture cells.  

PubMed

The goal of this study was develop a rapid high-throughput method for the assessment of the bacterial adhesion to tissue culture cells and test this method by investigation of the adhesion and growth of pathogenic and non-pathogenic Escherichia coli strains in the presence of HeLa human epithelial cells. Fifteen strains of E. coli were transformed with a plasmid carrying the entire lux operon of Photorhabdus luminescens to make them bioluminescent. By using the Time-to-Detection approach and bioluminescence imaging in microplate format, the adherence and growth of bacteria in tissue culture medium in the presence of HeLa cells was monitored. It was observed that Eagle's minimal essential medium (EMEM) supplemented with 10% fetal bovine serum (FBS) significantly inhibited growth of E. coli. However, in the presence of HeLa cells the detected growth of E. coli was similar to the growth observed in LB medium. It was established that the initial number of E. coli cells present in the microplate directly correlated with the time necessary for the bioluminescence signal to reach the threshold level, hence allowing the accurate assessment of the adhered cells within 8-10 h. Neither bacterial adherence nor growth kinetics correlated with the pathogenicity of the strain though they were strain-specific. The developed approach provided new information on the interaction of E. coli with epithelial cells and could be used for both pathogenicity research and for the screening of potential therapeutic agents for the ability to minimize pathogen colonization of human tissues. PMID:21337328

Brovko, L; Minikh, O; Piekna, A; Griffiths, M W

2011-02-24

40

MAMMALIAN CELL CULTURE ASSAY TO QUANTITATE CHEMICALLY INDUCED ANEUPLOIDY: USE OF A MONOCHROMOSOMAL HUMAN/MOUSE CELL HYBRID  

EPA Science Inventory

A short-term assay utilizing a human/mouse monochromosomal hybrid cell line R3-5, to detect chemically induced aneuploidy in mammalian cells is described. A single human chromosome transferred into mouse cells was used as a cytogenetic marker to quantitate abnormal chromosome seg...

41

Development of an in vitro quantal assay in primary cell cultures for a non-occluded baculo-like virus of penaeid shrimp  

Microsoft Academic Search

An in vitro quantal assay (TCID50) for a non-occluded baculo-like virus isolate from naturally infected Penaeus japonicus obtained from China and experimentally infected P. stylirostris was developed using primary shrimp lymphoid cell cultures in PrimariaTM 24-well tissue culture plates. The virus caused cytopathogenic effect (CPE) in the cell cultures as early as 2 day post-infection (p.i.). Initially, the cells rounded

Lourdes M. Tapay; Yuanan Lu; Remedios B. Gose; Elpidio Cesar B. Nadala; J. A. Brock; P. C. Loh

1997-01-01

42

Comparison of a Commercial Real-Time PCR Assay for tcdB Detection to a Cell Culture Cytotoxicity Assay and Toxigenic Culture for Direct Detection of Toxin-Producing Clostridium difficile in Clinical Samples?  

PubMed Central

Rapid detection of toxin-producing strains of Clostridium difficile is essential for optimal management of patients with C. difficile infection. The BD GeneOhm (San Diego, CA) Cdiff assay, a real-time PCR assay that amplifies tcdB, was compared to a cell culture neutralization assay (Wampole C. difficile Toxin B [TOX-B] test; TechLab, Blacksburg, VA) and to toxigenic culture. Using liquid (n = 273) and soft (n = 131) stool specimens from 377 symptomatic patients, all testing was performed on the same day by independent laboratory staff according to the manufacturers' protocols. Toxigenic bacterial culture was performed as follows. A 0.5-ml aliquot of stool was heated to 80°C for 10 min, followed by inoculation onto modified cycloserine cefoxitin fructose agar with and without horse blood (Remel, Lenexa, KS) and into prereduced chopped-meat broth. Of the 404 stool specimens tested, 340 were negative and 40 were positive (10.0% prevalence) both by PCR for tcdB and by cytotoxin production. The overall agreement between the BD GeneOhm Cdiff assay and the TOX-B test was 94.8% (380/401). When the TOX-B test was used as the reference method, the initial sensitivity, specificity, and positive and negative predictive values of the BD GeneOhm Cdiff assay were 90.9% (40/44), 95.2% (340/357), 70.2% (40/57), and 98.8% (340/344), respectively. When toxigenic culture was used as the “gold standard,” the sensitivity, specificity, and positive and negative predictive values of the BD GeneOhm Cdiff assay were 83.6%, 98.2%, 89.5%, and 97.1%, respectively, and those of the TOX-B test were 67.2%, 99.1%, 93.2%, and 94.4%, respectively. PCRs for three samples were inhibited upon initial testing; one sample was resolved upon retesting. One sample produced nonspecific cytotoxin results. The BD GeneOhm Cdiff assay performed well compared to a standard cell culture neutralization assay and to toxigenic culture for the detection of toxigenic C. difficile directly from fecal specimens.

Stamper, Paul D.; Alcabasa, Romina; Aird, Deborah; Babiker, Wisal; Wehrlin, Jennifer; Ikpeama, Ijeoma; Carroll, Karen C.

2009-01-01

43

Comparison of BGM and PLC/PRC/5 Cell Lines for Total Culturable Viral Assay of Treated Sewage?  

PubMed Central

The objective of this study was to compare PLC/PRF/5 and BGM cell lines for use in a total culturable viral assay (TCVA) of treated sewage effluents. Samples were collected before and after chlorination from an activated sludge wastewater treatment plant and from the effluent of a high-rate enhanced flocculation system, followed by UV light disinfection. Cell monolayers were observed for cytopathic effect (CPE) after two passages of 14 days each. Monolayers exhibiting viral CPE were tested for the presence of adenoviruses and enteroviruses by PCR or reverse transcription-PCR. Eight percent of the samples exhibited CPE on BGM cells, and 57% showed CPE on PLC/PRF/5 cells. Only enteroviruses were detected on the BGM cells, while 30% and 52% of the samples were positive for enteroviruses and adenoviruses, respectively, on the PLC/PRF/5 cells. Thirty percent of the samples were positive for both adenoviruses and enteroviruses in chlorinated activated sludge effluent. Thirty percent of the samples were positive for adenoviruses in the UV treatment effluent, but no enteroviruses were detected. In conclusion, the PLC/PRF/5 cells were more susceptible than BGM cells to viruses found in treated sewage. The use of BGM cells for TCVA may underestimate viral concentration in sewage effluent samples. The PLC/PRF/5 cells were more susceptible to adenoviruses, which is important in the evaluation of UV disinfection systems because adenoviruses are highly resistant to UV inactivation.

Rodriguez, Roberto A.; Gundy, Patricia M.; Gerba, Charles P.

2008-01-01

44

Primary cultures of embryonic chicken neurons for sensitive cell-based assay of botulinum neurotoxin: implications for therapeutic discovery.  

PubMed

Botulinum toxin is an exceedingly potent inhibitor of neurotransmission across the neuromuscular junction, causing flaccid paralysis and death. The potential for misuse of this deadly poison as a bioweapon has added a greater urgency to the search for effective therapeutics. The development of sensitive and efficient cell-based assays for the evaluation of toxin antagonists is crucial to the rapid and successful identification of therapeutic compounds. The authors evaluated the sensitivity of primary cultures from 4 distinct regions of the embryonic chick nervous system to botulinum neurotoxin A (BoNT/A) cleavage of synaptosomal-associated protein of 25 kD (SNAP-25). Although differences in sensitivity were apparent, SNAP-25 cleavage was detectable in neuronal cells from each of the 4 regions within 3 h at BoNT/A concentrations of 1 nM or lower. Co-incubation of chick neurons with BoNT/A and toxin-neutralizing antibodies inhibited SNAP-25 cleavage, demonstrating the utility of these cultures for the assay of BoNT/A antagonists. PMID:17332092

Stahl, Andrea M; Ruthel, Gordon; Torres-Melendez, Edna; Kenny, Tara A; Panchal, Rekha G; Bavari, Sina

2007-03-01

45

Comparison of Assays for Sensitive and Reproducible Detection of Cell Culture-Infectious Cryptosporidium parvum and Cryptosporidium hominis in Drinking Water  

PubMed Central

This study compared the three most commonly used assays for detecting Cryptosporidium sp. infections in cell culture: immunofluorescent antibody and microscopy assay (IFA), PCR targeting Cryptosporidium sp.-specific DNA, and reverse transcriptase PCR (RT-PCR) targeting Cryptosporidium sp.-specific mRNA. Monolayers of HCT-8 cells, grown in 8-well chamber slides or 96-well plates, were inoculated with a variety of viable and inactivated oocysts to assess assay performance. All assays detected infection with low doses of flow cytometry-enumerated Cryptosporidium parvum oocysts, including infection with one oocyst and three oocysts. All methods also detected infection with Cryptosporidium hominis. The RT-PCR assay, IFA, and PCR assay detected infection in 23%, 25%, and 51% of monolayers inoculated with three C. parvum oocysts and 10%, 9%, and 16% of monolayers inoculated with one oocyst, respectively. The PCR assay was the most sensitive, but it had the highest frequency of false positives with mock-infected cells and inactivated oocysts. IFA was the only infection detection assay that did not produce false positives with mock-infected monolayers. IFA was also the only assay that detected infections in all experiments with spiked oocysts recovered from Envirochek capsules following filtration of 1,000 liters of treated water. Consequently, cell culture with IFA detection is the most appropriate method for routine and sensitive detection of infectious Cryptosporidium parvum and Cryptosporidium hominis in drinking water.

Di Giovanni, George D.; Rochelle, Paul A.

2012-01-01

46

Evaluation of a Soluble Tetrazolium\\/Formazan Assay for Cell Growth and Drug Sensitivity in Culture Using Human and Other Tumor Cell Lines1  

Microsoft Academic Search

We have previously described the application of an automated micro- culture tetrazolium assay (MTA) involvingdimethyl sulfoxide solubiliza- tion of cellular-generated 3-{4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra- zolium bromide (MTTHormazan to the in vitro assessment of drug effects on cell growth (M. C. Alley et al., Proc. Am. Assen. Cancer Res., 27:389,1986; M. C. Alley et al.. Cancer Res. 48:589-601,1988). There are several inherent disadvantages of

Dominic A. Scudiere; Robert H. Shoemaker; Kenneth D. Paul; Anne Monks; Siobhan Tierney; Thomas H. Nofziger; Michael J. Currens; Donna Seniff; Michael R. Boyd

47

Critical illness polyneuropathy: clinical findings and cell culture assay of neurotoxicity assessed by a prospective study  

Microsoft Academic Search

Objective: First, to evaluate the role of typical intensive care-related conditions like sepsis, prolonged ventilation, drug effects and metabolic disorders in the pathogenesis of critical illness polyneuropathy (CIP); second, to investigate the possible significance of patient serum neurotoxicity assessed by an in vitro cytotoxicity assay with respect to CIP development. Design: Prospective study. Setting: Neurological intensive care unit. Patients and

A. Druschky; M. Herkert; M. Radespiel-Tröger; K. Druschky; E. Hund; C.-M. Becker; M. J. Hilz; F. Erbguth; B. Neundörfer

2001-01-01

48

Filtration assay for quantitation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) specific binding to whole cells in culture  

Microsoft Academic Search

A rapid and sensitive filtration assay for quantitating the specific binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to whole cells in culture is described. Cell monolayers are incubated with (3H)TCDD in the presence or absence of excess unlabeled ligand, detached from the culture dish with trypsin, filtered, and washed with cold (-78°C) acetone to separate free and nonspecifically bound TCDD from specifically bound

K. M. Dold; W. F. Greenlee

1990-01-01

49

Inter-experiment variation and dependence on culture conditions in assaying the chemosensitivity of human small cell lung cancer cell lines.  

PubMed

Sensitivity of five human small cell lung cancer cell lines to doxorubicin was assessed by a double layer agar technique using two different bottom-layers. Neither of the bottom-layers provided proportionality between numbers of cells plated and numbers of colonies, but they were correlated by a logarithmic function. Even after correction for lack of proportionality the two assay systems provided significantly different dose-response curves. The stability of the chemosensitivity was tested after 25-30 weeks continuous in vitro culture or prolonged storage in liquid nitrogen. One cell line underwent significant changes after continuous in vitro culture whereas the cell lines tested after prolonged storage in liquid nitrogen showed only minor changes. It is concluded that instead of considering the concentration necessary to achieve a certain degree of cell kill (e.g. ID50) in one experiment on one cell line, dose-response curves obtained on several cell lines in different assay systems should be used in the evaluation of new drugs. PMID:2832177

Roed, H; Christensen, I B; Vindelřv, L L; Spang-Thomsen, M; Hansen, H H

1987-02-01

50

Evaluation of a Multiple-Cycle, Recombinant Virus, Growth Competition Assay That Uses Flow Cytometry To Measure Replication Efficiency of Human Immunodeficiency Virus Type 1 in Cell Culture  

Microsoft Academic Search

Human immunodeficiency virus type 1 (HIV-1) replication efficiency or fitness, as measured in cell culture, has been postulated to correlate with clinical outcome of HIV infection, although this is still controversial. One limitation is the lack of high-throughput assays that can measure replication efficiency over multiple rounds of replication. We have developed a multiple-cycle growth competition assay to measure HIV-1

Carrie Dykes; Jiong Wang; Xia Jin; Vicente Planelles; Dong Sung An; Amanda Tallo; Yangxin Huang; Hulin Wu; Lisa M. Demeter

2006-01-01

51

Cell-culture assays reveal the importance of retroviral vector design for insertional genotoxicity  

Microsoft Academic Search

Retroviral vectors with long terminal re- peats (LTRs), which contain strong en- hancer\\/promoter sequences at both ends of their genome, are widely used for stable gene transfer into hematopoietic cells. However, recent clinical data and mouse models point to insertional activation of cellular proto-oncogenes as a dose- limiting side effect of retroviral gene deliv- ery that potentially induces leukemia. Self-

Ute Modlich; Jens Bohne; Manfred Schmidt; Christof von Kalle; Sabine Knoss; Axel Schambach; Christopher Baum

2006-01-01

52

Development of Quantitative Microscopy-Based Assays for Evaluating Dynamics of Living Cultures of Mouse Spermatogonial Stem/Progenitor Cells1  

PubMed Central

ABSTRACT Spermatogonial stem cell (SSC) self-renewal and differentiation are required for continuous production of spermatozoa and long-term fertility. Studying SSCs in vivo remains challenging because SSCs are rare cells and definitive molecular markers for their identification are lacking. The development of a method for propagating SSCs in vitro greatly facilitated analysis of SSCs. The cultured cells grow as clusters of a dynamic mixture of “true” stem cells and differentiating progenitor cells. Cells in the stem/progenitor culture system share many properties with spermatogonia in vivo; however, to fully exploit it as a model for spermatogonial development, new assays are needed that account for the dynamic heterogeneity inherent in the culture system. Here, assays were developed for quantifying dynamics of cultures of stem/progenitor cells that expressed histone-green fluorescent protein (GFP). First, we built on published results showing that cluster formation in vitro reliably predicts the relative number of SSCs. The GFP-based in vitro cluster assay allows quantification of SSCs with significantly fewer resources than a transplantation assay. Second, we compared the dynamics of differentiation in two experimental paradigms by imaging over a 17-day time frame. Finally, we performed short-term live imaging and observed cell migration, coordinated cell proliferation, and cell death resembling that of spermatogonia in the testes. The methods that we present provide a foundation for the use of fluorescent reporters in future microscopy-based high-throughput screens by using living spermatogonial stem/progenitor cultures applicable to toxicology, contraceptive discovery, and identification of regulators of self-renewal and differentiation.

Heim, Crystal N.; Fanslow, Danielle A.; Dann, Christina Tenenhaus

2012-01-01

53

Cell motility assays.  

PubMed

This report summarises practical aspects to measuring cell motility in culture. The methods described here were discussed at a 1-day European Tissue Culture Society (ETCS-UK) workshop organised by John Masters and Gareth E Jones that was held at University College London on 19th April 2007. PMID:18071914

Hague, Angela; Jones, Gareth E

2007-12-11

54

Neutral red (NR) assay for cell viability and xenobiotic-induced cytotoxicity in primary cultures of human and rat hepatocytes  

Microsoft Academic Search

Neutral red (NR) in medium was absorbed and concentrated in lysosomes of cultured rat and human hepatocytes. NR uptake increased with the time of incubation and reached a plateau in 2 hr. Uptake was proportional to the concentration of the NR solution and the numbers of viable liver cells. Prolonged culture of hepatocytes increased the numbers of lysosomes, and thus,

Shao-Zeng Zhang; Michael M. Lipsky; Benjamin F. Trump; Ih-Chang Hsu

1990-01-01

55

Investigation of sequential behavior of carboxyl protease and cysteine protease activities in virus-infected Sf9 insect cell culture by inhibition assay  

Microsoft Academic Search

Proteases produced during the culture of Spodoptera frugiperda Sf-9 cells infected with Autographa californica nuclear polyhedrosis virus (AcNPV) were assayed with various protease inhibitors. This inhibitory analysis revealed that: (1) carboxyl and cysteine proteases were predominantly produced by the insect cells infected with recombinant AcNPV, the gene of which encoded a variant of green fluorescent protein in a portion of

T. Gotoh; Y. Miyazaki; K.-I. Kikuchi; W. E. Bentley

2001-01-01

56

Basics of Cell Culture  

NSDL National Science Digital Library

These manuals are used in the Stem Cell Culture Course at City College of San Francisco. This course is about general mammalian cell culture techniques but includes a laboratory exercise using stem cells (takes 3 weeks to complete). The course is taught to high school students but the materials are also used for college students. Laboratory exercises provide instruction in basic techniques of routine cell culture using common cell lines before progressing to differentiation of mouse embryonic stem cells. Photographs and explanations of common equipment (laminar flow hood, inverted microscope, etc.) and reagents are provided. Laboratory exercises include the following: Basic Aseptic Technique; Media Preparation; Plating cells from frozen stock; Cell counting and plating; Survival assay (UV); Live Cell Identification; Transfection; Freezing cells; Stem cell differentiation. A student lab manual and an instructor manual are provided.

Afshar, Golnar

2012-03-12

57

Primary Cultures of Embryonic Chicken Neurons for Sensitive Cell-Based Assay of Botulinum Neurotoxin: Implications for Therapeutic Discovery  

Microsoft Academic Search

Botulinum toxin is an exceedingly potent inhibitor of neurotransmission across the neuromuscular junction, causing flaccid paralysis and death. The potential for misuse of this deadly poison as a bioweapon has added a greater urgency to the search for effective therapeutics. The development of sensitive and efficient cell-based assays for the evaluation of toxin antagonists is crucial to the rapid and

Andrea M. Stahl; Gordon Ruthel; Edna Torres-Melendez; Tara A. Kenny; Rekha G. Panchal; Sina Bavari

2007-01-01

58

Evaluation of a multiple-cycle, recombinant virus, growth competition assay that uses flow cytometry to measure replication efficiency of human immunodeficiency virus type 1 in cell culture.  

PubMed

Human immunodeficiency virus type 1 (HIV-1) replication efficiency or fitness, as measured in cell culture, has been postulated to correlate with clinical outcome of HIV infection, although this is still controversial. One limitation is the lack of high-throughput assays that can measure replication efficiency over multiple rounds of replication. We have developed a multiple-cycle growth competition assay to measure HIV-1 replication efficiency that uses flow cytometry to determine the relative proportions of test and reference viruses, each of which expresses a different reporter gene in place of nef. The reporter genes are expressed on the surface of infected cells and are detected by commercially available fluorescence-labeled antibodies. This method is less labor-intensive than those that require isolation and amplification of nucleic acids. The two reporter gene products are detected with similar specificity and sensitivity, and the proportion of infected cells in culture correlates with the amount of viral p24 antigen produced in the culture supernatant. HIV replication efficiencies of six different drug-resistant site-directed mutants were reproducibly quantified and were similar to those obtained with a growth competition assay in which the relative proportion of each variant was measured by sequence analysis, indicating that recombination between the pol and reporter genes was negligible. This assay also reproducibly quantified the relative fitness conferred by protease and reverse transcriptase sequences containing multiple drug resistance mutations, amplified from patient plasma. This flow cytometry-based growth competition assay offers advantages over current assays for HIV replication efficiency and should prove useful for the evaluation of patient samples in clinical trials. PMID:16757582

Dykes, Carrie; Wang, Jiong; Jin, Xia; Planelles, Vicente; An, Dong Sung; Tallo, Amanda; Huang, Yangxin; Wu, Hulin; Demeter, Lisa M

2006-06-01

59

21 CFR 866.2350 - Microbiological assay culture medium.  

Code of Federal Regulations, 2013 CFR

... false Microbiological assay culture medium. 866.2350 Section 866.2350 ...2350 Microbiological assay culture medium. (a) Identification. A microbiological assay culture medium is a device that consists...

2013-04-01

60

Comparison of rt pcr assay and virus isolation in cell cultures for the detection of bovine viral diarrhoea virus ( bvdv) in field samples  

Microsoft Academic Search

The virus isolation-immunoperoxidase test (ipx) on cell cultures and the reverse transcription-polymerase chain reaction (rt-pcr) assay were compared for the detection of bovine viral diarrhoea virus (bvdv) directly in serum samples. Material for this study consisted of 403 sera originating from cattle in 41 bvdv-infected Finnish dairy herds and one suckler cow herd. The presence of virus was demonstrated in

U. I Laamanen; E. P Neuvonen; E. M Yliviuhkola; P. M.-L Veijalainen

1997-01-01

61

Cell aggregation assays.  

PubMed

Invasion of carcinoma cells is the result of a disequilibrium between invasion promoter and invasion suppressor gene products (Mareel and Van Roy, Anticancer Res 6:419-435, 1986). The E-cadherin/catenin complex is the most potent invasion suppressor at the cell membrane of epithelioid cells (Duffy et al., J Pathol 214:283-293, 2008). This complex consists of E-cadherin, a transmembrane glycoprotein of 120 kDa, which is linked to the actin cytoskeleton via the catenins (Behrens et al., J Cell Biol 108:2435-2447, 1989). Downregulation of the complex is a common feature in invasive carcinoma cells, and has been recognized at several levels, ranging from genomic mutations to functional deficiencies of an apparently intact complex (Ozawa et al., Proc Natl Acad Sci USA 87:4246-4250, 1990). Cell aggregation assays have been set up to test the functionality of the complex in epithelioid tumor cells. Functional integrity of the complex is a prerequisite for cell-cell adhesion between epithelial cells, and measuring cell aggregation in vitro has thus become another elegant tool to study differences between invasive and noninvasive cell types. PMID:24092433

Debruyne, Delphine; Boterberg, Tom; Bracke, Marc E

2014-01-01

62

Fluorimetric DNA assay for cell growth estimation.  

PubMed

A growth assay using the fluorescent dye Hoechst 33258 has been developed which allows sensitive and rapid analysis of the DNA content of a variety of cell types including keratinocytes and mucus-secreting cells, and which requires a minimum of liquid handling. The assay can detect as few as 500 diploid human cells, and is compatible with the simultaneous detection of [3H]thymidine incorporation in the same cultures. PMID:1489093

Rao, J; Otto, W R

1992-11-15

63

An assay combining cell culture with reverse transcriptase PCR to detect and determine the infectivity of waterborne Cryptosporidium parvum.  

PubMed Central

The presence of Cryptosporidium in drinking water supplies is a significant problem faced by the water industry. Although a variety of methods exist for the detection of waterborne oocysts, water utilities currently have no way of assessing the infectivity of detected oocysts and consequently are unable to accurately determine the risks posed to public health by waterborne Cryptosporidium. In this paper, the development of an infectivity assay for waterborne Cryptosporidium parvum is described. Oocysts were inoculated onto monolayers of Caco-2 cells and grown on microscope slides, and infections were detected by C. parvum specific reverse transcriptase PCR of extracted mRNA, targeting the heat shock protein 70 (hsp70) gene. A single infectious oocyst was detected by this experimental procedure. The use of concentrated samples obtained from 250 liters of finished water had no observable effect on the integrity of cell monolayers or on the infectivity of oocysts seeded into the concentrate. Intracellular developmental stages of the parasite were also detected by using fluorescently labeled antibodies. One pair of PCR primers targeting the hsp70 gene was specific for C. parvum, while a second pair recognized all species of Cryptosporidium tested. The C. parvum-specific primers amplified DNA from 1 to 10 oocysts used to seed 65 to 100 liters of concentrated environmental water samples and were compatible with multiplex PCR for the simultaneous detection of C. parvum and Giardia lambia. This paper confirms the utility of PCR for the detection of waterborne C. parvum and, most importantly, demonstrates the potential of an in vitro infectivity assay.

Rochelle, P A; Ferguson, D M; Handojo, T J; De Leon, R; Stewart, M H; Wolfe, R L

1997-01-01

64

Advances in cell culture  

SciTech Connect

This book presents papers on advances in cell culture. Topics covered include: Genetic changes in the influenza viruses during growth in cultured cells; The biochemistry and genetics of mosquito cells in culture; and Tree tissue culture applications.

Maramorosch, K. (Dept. of Entomology, Rutgers Univ., New Brunswick, NJ (US))

1987-01-01

65

In vitro antitumor effect of recombinant human tumor necrotizing factor on cultured human cancer cell lines and freshly isolated lung cancer cells by the human tumor clonogenic assay  

Microsoft Academic Search

In vitro antitumor effects of human recombinant tumor necrotizing factor (rH-TNF) were examined against nine lung cancer cell lines including six non small and three small cell lung cancer, four stomach cancer cell lines and 30 freshly isolated lung cancer cell samples by the human tumor clonogenic assay. rH-TNF did not show any inhibitory effect on the colony formations of

Yasutsuna Sasaki; Fumihiko Kanzawa; Hidenobu Takahashi; Yuka Matsushima; Hidehiko Nakano; Kazuhiko Nakagawa; Weon Seon Hong; Koichi Minato; Yasuhiro Fujiwara; Nagahiro Saijo

1987-01-01

66

Phosphate Stress in Cultures and Field Populations of the Dinoflagellate Prorocentrum minimum Detected by a Single-Cell Alkaline Phosphatase Assay  

PubMed Central

Alkaline phosphatase activity is a common marker of phosphate stress in many phytoplankton, but it has been difficult to attribute alkaline phosphatase activity to specific organisms or groups of phytoplankton in the field with traditional biochemical procedures. A new alkaline phosphatase substrate, ELF-97 (enzyme-labeled fluorescence), shows promise in this regard. When a phosphate group is cleaved from the ELF-97 reagent, the remaining molecule precipitates near the site of enzyme activity, thus fluorescently tagging cells with alkaline phosphatase activity. We characterized ELF-97 labeling in axenic cultures of a common dinoflagellate, Prorocentrum minimum, in order to understand ELF-97 labeling dynamics when phosphate nutrition varies. Enzyme activity, as detected by ELF-97 labeling, appears to be induced in late-log- or early-stationary-phase cultures if cells are grown in low-phosphate media and is lost when phosphate-stressed cells are refed with phosphate. ELF-97 appears to label an inducible intracellular alkaline phosphatase in P. minimum based on confocal microscopy studies. This may limit the use of this reagent to organisms that lack high levels of constitutive intracellular phosphatases. After laboratory cultures were characterized, ELF-97 was used to assay field populations of P. minimum in Narragansett Bay during two 1-week periods, and 12 to 100% of the P. minimum cells were labeled. The level of cell labeling was reduced by 3 days of incubation with added inorganic phosphate. Our results indicate that ELF-97 is an excellent new tool for monitoring phytoplankton phosphate stress in the environment when the data are supported by appropriate laboratory studies.

Dyhrman, Sonya T.; Palenik, Brian

1999-01-01

67

An optimized microplate assay system for quantitative evaluation of plant cell wall-degrading enzyme activity of fungal culture extracts.  

PubMed

Developing enzyme cocktails for cellulosic biomass hydrolysis complementary to current cellulase systems is a critical step needed for economically viable biofuels production. Recent genomic analysis indicates that some plant pathogenic fungi are likely a largely untapped resource in which to prospect for novel hydrolytic enzymes for biomass conversion. In order to develop high throughput screening assays for enzyme bioprospecting, a standardized microplate assay was developed for rapid analysis of polysaccharide hydrolysis by fungal extracts, incorporating biomass substrates. Fungi were grown for 10 days on cellulose- or switchgrass-containing media to produce enzyme extracts for analysis. Reducing sugar released from filter paper, Avicel, corn stalk, switchgrass, carboxymethylcellulose, and arabinoxylan was quantified using a miniaturized colorimetric assay based on 3,5-dinitrosalicylic acid. Significant interactions were identified among fungal species, growth media composition, assay substrate, and temperature. Within a small sampling of plant pathogenic fungi, some extracts had crude activities comparable to or greater than T. reesei, particularly when assayed at lower temperatures and on biomass substrates. This microplate assay system should prove useful for high-throughput bioprospecting for new sources of novel enzymes for biofuel production. PMID:18973283

King, Brian C; Donnelly, Marie K; Bergstrom, Gary C; Walker, Larry P; Gibson, Donna M

2009-03-01

68

Cell Culture Models for Neurotoxicology  

Microsoft Academic Search

A range of in vitro cell culture methods are available for neurotoxicology which typically represent one of the two predominant cell types present in the brain, neurons and glial cells. These systems can be used in a two tiered approach, whereby simple cytotoxic models reveal the gross effects of a drug or compound and, subsequently, more complex and subtle assays

Glyn Stacey; Barbara Viviani

2001-01-01

69

An optimized microplate assay system for quantitative evaluation of plant cell wall-degrading enzyme activity of fungal culture extracts  

Microsoft Academic Search

Developing enzyme cocktails for cellulosic bio- mass hydrolysis complementary to current cellulase systems is a critical step needed for economically viable biofuels production. Recent genomic analysis indicates that some plant pathogenic fungi are likely a largely untapped resource in which to prospect for novel hydrolytic enzymes for biomass conversion. In order to develop high throughput screening assays for enzyme bioprospecting,

Brian C. King; Marie K. Donnelly; Gary C. Bergstrom; Larry P. Walker; Donna M. Gibson

2009-01-01

70

Transducin-alpha C-terminal mutations prevent activation by rhodopsin: a new assay using recombinant proteins expressed in cultured cells.  

PubMed Central

We have measured the activation by recombinant rhodopsin of the alpha-subunit (alpha 1) of retinal transducin (Gt, also recombinant) using a new assay. Cultured cells are transiently transfected with DNAs encoding opsin and the three subunits of Gt (alpha t, beta 1 and gamma 1). In the microsomes of these cells, incubated with 11-cis-retinal, light causes the rapid activation of Gt, as measured by the ability of GTP gamma S to protect alpha t fragments from proteolytic degradation. The activation of Gt is also observed when all-trans-retinal is added to microsomes under constant illumination. Activation depends on both opsin and retinal. Opsin mutants with known defects in activating Gt show similar defects in this assay. alpha t mutations that mimic the corresponding mutations in the alpha-subunit of Gs also produce qualitatively similar effects in this assay. As a first step in a strategy aimed at exploring the relationships between structure and function in the interactions of receptors with G proteins, we tested mutant alpha t proteins with alanine substituted for each of the 10 amino acids at the C-terminus, a region known to be crucial for interactions with rhodopsin. Alanine substitution at four positions moderately (K341) or severely (L344, G348, L349) impairs the susceptibility of alpha 1 to activation by rhodopsin. All four mutants retain their ability to be activated by AIF-4. Two other substitutions (N343 and F350) resulted in very mild defects, while substitutions at the remaining four positions (E342, K345, D346 and C347) had no effect. In combination with previous observations, these results constrain models of the interaction of the C-terminus of alpha t with rhodopsin. Images

Garcia, P D; Onrust, R; Bell, S M; Sakmar, T P; Bourne, H R

1995-01-01

71

A Cell Programmable Assay (CPA) chip.  

PubMed

This article describes two kinds of "Cell Programmable Assay" (CPA) chips that utilize passive pumping for the culture and autonomous staining of cells to simply common protocols. One is a single timer channel CPA (sCPA) chip that has one timer channel and one main channel containing a cell culture chamber. The sCPA is used to culture and stain cells using Hoechst nuclear staining dye (a 2 step staining process). The other is a dual timer channel CPA (dCPA) chip that has two timer channels and one main channel with a chamber for cell culture. The dCPA is used here to culture, fix, permeablize, and stain cells using DAPI. The additional timer channel of the dCPA chip allows for automation of 3 steps. The CPA chips were successfully evaluated using HEK 293 cells. In addition, we provide a simplified equation for tuning or redesigning CPA chips to meet the needs of a variety of protocols that may require different timings. The equation is easy to use as it only depends upon the dimensions of microchannel and the volume of the reagent drops. The sCPA and dCPA chips can be readily modified to apply to a wide variety of common cell culture methods and procedures. PMID:20614082

Ju, Jongil; Warrick, Jay; Beebe, David J

2010-07-08

72

Correlation between Clostridium difficile Bacterial Load, Commercial Real-Time PCR Cycle Thresholds, and Results of Diagnostic Tests Based on Enzyme Immunoassay and Cell Culture Cytotoxicity Assay.  

PubMed

The impact of Clostridium difficile fecal loads on diagnostic test results is poorly understood, but it may have clinical importance. In this study, we investigated the relationship between C. difficile fecal load and the results of four assays: a glutamate dehydrogenase (GDH) enzyme immunoassay (EIA), a toxin A/B antigen EIA (ToxAB), a cell culture cytotoxicity assay (CCA), and PCR targeting the tcdB gene. We also compared the PCR cycle threshold (CT) with the results of quantitative culture using Spearman's rank correlation coefficient. Finally, we sequenced the genomes of 24 strains with different detection profiles. A total of 203 clinical samples harboring toxigenic C. difficile were analyzed and sorted into one of four groups: 17 PCR(+) (group 1), 37 PCR(+) GDH(+) (group 2), 24 PCR(+) GDH(+) CCA(+) (group 3), and 125 PCR(+) GDH(+) ToxAB(+) (group 4). The overall median fecal load in log10 CFU/g was 6.67 (interquartile range [IQR], 5.57 to 7.54). The median fecal bacterial load of groups 1, 2, 3, and 4 were 4.15 (IQR, 3.00 to 4.98), 5.74 (IQR, 4.75 to 6.16), 6.20 (IQR, 5.23 to 6.80), and 7.08 (IQR, 6.35 to 7.83), respectively. Group 1 samples had lower fecal loads than those from each of the other groups (P < 0.001). Group 2 samples had lower fecal loads than those from groups 3 and 4 (P < 0.001). There was a significant correlation between PCR CT and fecal loads (? = -0.697; P < 0.001). NAP1 strains were associated with the detection of toxins by EIA or CCA (P = 0.041). This study demonstrates an association between C. difficile fecal load and the results of routinely used diagnostic tests. PMID:23966497

Dionne, Léa-Laurence; Raymond, Frédéric; Corbeil, Jacques; Longtin, Jean; Gervais, Philippe; Longtin, Yves

2013-08-21

73

Changes in gene expression profile by HCV core protein in cultured liver cells: analysis by DNA array assay.  

PubMed

In this study, we established hepatitis C virus (HCV) core-expressing mouse liver cells and investigated changes occurring in the gene expression profile accompanied by expression of the viral core protein using DNA array analysis. Both non-transformed and transformed mouse liver cells constitutively expressing the viral core protein were established by DNA transfection, and subjected to DNA array analysis. For the genes judged positive by DNA array, Northern blot analysis was done for corroboration. DNA array analysis revealed one up-regulated gene and three down-regulated genes by expression of the viral core protein in non-transformed liver cells. For the transformed liver cells, four enhanced and five suppressed genes were observed. The Northern blot corroboration analysis clarified two genes, osteopontin precursor and activating transcription factor 4, as being down-regulated by the viral core protein in both non-transformed and transformed liver cells, and three genes, cathepsin D, matrix metalloproteinase 14 and anti-proliferative B-cell translocation gene 2, as being up-regulated by the viral core protein in only transformed liver cells. In conclusion, a total of five genes were identified as viral core protein-responsive ones in the DNA array analysis. Alterations in the expression levels of these genes may be relevant to the viral core-mediated pathogenesis. PMID:12699850

Ohkawa, Kazuyoshi; Ishida, Hisashi; Nakanishi, Fumihiko; Hosui, Atsushi; Sato, Aki; Ueda, Keiji; Takehara, Tetsuo; Kasahara, Akinori; Sasaki, Yutaka; Hori, Masatsugu; Hayashi, Norio

2003-04-01

74

Colony forming cell assays for human hematopoietic progenitor cells.  

PubMed

Hematopoietic stem cells (HSCs) present in small numbers in adult bone marrow (BM), peripheral blood (PB) and umbilical cord blood (CB) produce a heterogeneous pool of progenitors that can be detected in vitro using colony forming cell (CFC) assays. Hematopoietic progenitor cells proliferate and differentiate to produce colonies of maturing cells when cultured in a semisolid methylcellulose-based medium that is supplemented with suitable growth factors and other supplements. The colonies are then classified and enumerated in situ by light microscopy or an automated imaging instrument. CFC assays are important tools in basic hematology research but are also used by clinical cell processing laboratories to measure the progenitor cell content of BM, CB and mobilized PB (MPB) preparations used for cell transplantation. Standard CFC assays for human progenitor cells require a culture period of at least 14 days to enable optimal outgrowth and differentiation of the maximum number of CFCs in a cell preparation. In this chapter protocols are described for the detection and enumeration of myeloid multipotential progenitors and committed progenitors of the erythroid, monocyte, and granulocyte lineages in samples from human PB, MPB, BM, and CB. In addition protocols are described for a modified version of the CFC-assay that allows accurate enumeration of total CFC numbers in CB or MPB after a culture period of only 7 days, but without distinction of colony types. PMID:23179838

Wognum, Bert; Yuan, Ning; Lai, Becky; Miller, Cindy L

2013-01-01

75

Enrichment of slow-growing marine microorganisms from mixed cultures using gel microdrop (GMD) growth assay and fluorescence-activated cell sorting  

Microsoft Academic Search

Encapsulation of cells in agarose gel microdrops (GMDs) combined with fluorescence-activated cell sorting (FACS) has been used previously to analyze and recover specific mammalian, bacterial, and yeast cell populations. Recently, we have developed a method to enrich mixed bacterial populations for slow-growing microorganisms using the GMD Growth Assay combined with fluorochrome staining and flow cytometry. Here, we demonstrate the feasibility

Y. Akselband; C. Cabral; T. P. Castor; H. M. Chikarmane; P. McGrath

2006-01-01

76

A Voltage-Sensitive Dye-Based Assay for the Identification of Differentiated Neurons Derived from Embryonic Neural Stem Cell Cultures  

Microsoft Academic Search

BackgroundPluripotent and multipotent stem cells hold great therapeutical promise for the replacement of degenerated tissue in neurological diseases. To fulfill that promise we have to understand the mechanisms underlying the differentiation of multipotent cells into specific types of neurons. Embryonic stem cell (ESC) and embryonic neural stem cell (NSC) cultures provide a valuable tool to study the processes of neural

Richardson N. Leăo; Amilcar Reis; Amanda Emirandetti; Michalina Lewicka; Ola Hermanson; André Fisahn; Wei-Chun Chin

2010-01-01

77

Histatins are the major wound-closure stimulating factors in human saliva as identified in a cell culture assay.  

PubMed

Wounds in the oral cavity heal much faster than skin lesions. Among other factors, saliva is generally assumed to be of relevance to this feature. Rodent saliva contains large amounts of growth factors such as epidermal growth factor (EGF) and nerve growth factor (NGF). In humans, however, the identity of the involved compounds has remained elusive, especially since EGF and NGF concentrations are approximately 100,000 times lower than those in rodent saliva. Using an in vitro model for wound closure, we examined the properties of human saliva and the fractions that were obtained from saliva by high-performance liquid chromotography (HPLC) separation. We identified histatin 1 (Hst1) and histatin 2 (Hst2) as major wound-closing factors in human saliva. In contrast, the d-enantiomer of Hst2 did not induce wound closure, indicating stereospecific activation. Furthermore, histatins were actively internalized by epithelial cells and specifically used the extracellular signal-regulated kinases 1/2 (ERK1/2) pathway, thereby enhancing epithelial migration. This study demonstrates that members of the histatin family, which up to now were implicated in the antifungal weaponry of saliva, exert a novel function that likely is relevant for oral wound healing. PMID:18650243

Oudhoff, Menno J; Bolscher, Jan G M; Nazmi, Kamran; Kalay, Hakan; van 't Hof, Wim; Amerongen, Arie V Nieuw; Veerman, Enno C I

2008-07-23

78

The Use of Cultured Primary Bovine Colon Epithelial Cells as a Screening Model to Detect Genotoxic Effects of Heterocyclic Aromatic Amines in the Comet Assay  

Microsoft Academic Search

Isolated epithelial cells from the bovine colon were maintained in dividing monolayer cultures and used as a model system for colon tissue in in vitro toxicological studies. The cytotoxic effects of the heterocyclic aromatic amines 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhiP) were investigated in these cells and IC50 values were determined by inhibition of neutral red uptake into the cultured

Wolfram Föllmann; Sascha Birkner

2008-01-01

79

Integrated microfluidic devices for combinatorial cell-based assays  

PubMed Central

The development of miniaturized cell culture platforms for performing parallel cultures and combinatorial assays is important in cell biology from the single-cell level to the system level. In this paper we developed an integrated microfluidic cell-culture platform, Cell-microChip (Cell-?Chip), for parallel analyses of the effects of microenvir-onmental cues (i.e., culture scaffolds) on different mammalian cells and their cellular responses to external stimuli. As a model study, we demonstrated the ability of culturing and assaying several mammalian cells, such as NIH 3T3 fibro-blast, B16 melanoma and HeLa cell lines, in a parallel way. For functional assays, first we tested drug-induced apoptotic responses from different cell lines. As a second functional assay, we performed "on-chip" transfection of a reporter gene encoding an enhanced green fluorescent protein (EGFP) followed by live-cell imaging of transcriptional activation of cyclooxygenase 2 (Cox-2) expression. Collectively, our Cell-?Chip approach demonstrated the capability to carry out parallel operations and the potential to further integrate advanced functions and applications in the broader space of combinatorial chemistry and biology.

Yu, Zeta Tak For; Kamei, Ken-ichiro; Takahashi, Hiroko; Shu, Chengyi Jenny; Wang, Xiaopu; He, George Wenfu; Silverman, Robert

2010-01-01

80

A Voltage-Sensitive Dye-Based Assay for the Identification of Differentiated Neurons Derived from Embryonic Neural Stem Cell Cultures  

PubMed Central

Background Pluripotent and multipotent stem cells hold great therapeutical promise for the replacement of degenerated tissue in neurological diseases. To fulfill that promise we have to understand the mechanisms underlying the differentiation of multipotent cells into specific types of neurons. Embryonic stem cell (ESC) and embryonic neural stem cell (NSC) cultures provide a valuable tool to study the processes of neural differentiation, which can be assessed using immunohistochemistry, gene expression, Ca2+-imaging or electrophysiology. However, indirect methods such as protein and gene analysis cannot provide direct evidence of neuronal functionality. In contrast, direct methods such as electrophysiological techniques are well suited to produce direct evidence of neural functionality but are limited to the study of a few cells on a culture plate. Methodology/Principal Findings In this study we describe a novel method for the detection of action potential-capable neurons differentiated from embryonic NSC cultures using fast voltage-sensitive dyes (VSD). We found that the use of extracellularly applied VSD resulted in a more detailed labeling of cellular processes compared to calcium indicators. In addition, VSD changes in fluorescence translated precisely to action potential kinetics as assessed by the injection of simulated slow and fast sodium currents using the dynamic clamp technique. We further demonstrate the use of a finite element model of the NSC culture cover slip for optimizing electrical stimulation parameters. Conclusions/Significance Our method allows for a repeatable fast and accurate stimulation of neurons derived from stem cell cultures to assess their differentiation state, which is capable of monitoring large amounts of cells without harming the overall culture.

Emirandetti, Amanda; Lewicka, Michalina; Hermanson, Ola; Fisahn, Andre

2010-01-01

81

Cell Culture Made Easy.  

ERIC Educational Resources Information Center

|Outlines steps to generate cell samples for observation and experimentation. The procedures (which use ordinary laboratory equipment) will establish a short-term primary culture of normal mammalian cells. Information on culture vessels and cell division and a list of questions to generate student interest and involvement in the topics are…

Dye, Frank J.

1985-01-01

82

Optimizing stem cell culture  

PubMed Central

Stem cells always balance between self-renewal and differentiation. Hence, stem cell culture parameters are critical and need to be continuously refined according to progress in our stem cell biology understanding and the latest technological developments. This led to the progressive replacement of ill-defined additives such as serum or feeder cell layers by recombinant cytokines or growth factors. Another example is the control of the oxygen pressure. For many years cell cultures have been done under atmospheric oxygen pressure which is much higher than the one experienced by stem cells in vivo. A consequence of cell metabolism is that cell culture conditions are constantly changing. Therefore, the development of high sensitive monitoring processes and control algorithms is required for ensuring cell culture medium homeostasis. Stem cells also sense the physical constraints of their microenvironment. Rigidity, stiffness and geometry of the culture substrate influence stem cell fate. Hence, nanotopography is probably as important as medium formulation in the optimization of stem cell culture conditions. Recent advances include the development of synthetic bioinformative substrates designed at the micro- and nanoscale level. On going research in many different fields including stem cell biology, nanotechnology, and bioengineering suggest that our current way to culture cells in Petri dish or flasks will soon be outdated as flying across the Atlantic Ocean in the Lindbergh’s plane.

Van Der Sanden, Boudewijn; Dhobb, Mehdi; Berger, Francois; Wion, Didier

2010-01-01

83

Stem cell culture engineering  

Microsoft Academic Search

Stem cells have the capacity for self renewal and undergo multilineage differentiation. Stem cells isolated from both blastocysts and adult tissues represent valuable sources of cells for applications in cell therapy, drug screening and tissue engineering. While expanding stem cells in culture, it is critical to maintain their self?renewal and differentiation capacity. In generating particular cell types for specific applications,

Gargi Seth; Catherine M. Verfaillie

2005-01-01

84

Comparison of the plaque assay and 50% tissue culture infectious dose assay as methods for measuring filovirus infectivity.  

PubMed

Two common methods of quantifying filovirus infectivity, a plaque assay and 50% cell culture infectious dose (TCID50) endpoint dilution assay, were compared. The two assays were performed side by side using the same virus stock sample to determine the correlation between the results of the two assays. The TCID50 assay appeared to be more sensitive but slightly more variable, and there was a tenfold difference in the numerical results of these methods of enumeration. The advantages and disadvantages of both assays are discussed. Both methods are useful and practicable in filovirus research, and this comparison will be hugely beneficial to the filovirus research community as it seeks to become more united. Further work in this area should be performed to ensure consistency in filovirus research. PMID:23748121

Smither, Sophie J; Lear-Rooney, Calli; Biggins, Julia; Pettitt, Jamie; Lever, Mark S; Olinger, Gene G

2013-06-05

85

Plant cell suspension cultures.  

PubMed

Plant cell suspension cultures are widely used in plant biology as a convenient tool for the investigation of a wide range of phenomena, bypassing the structural complexity of the plant organism in toto. The homogeneity of an in vitro cell population, the large availability of material, the high rate of cell growth and the good reproducibility of conditions make suspension-cultured cells suitable for the analysis of complex physiological processes at the cellular and molecular levels. Moreover, plant cell cultures provide a valuable platform for the production of high-value secondary metabolites and other substances of commercial interest. Here we describe how to initiate and maintain plant cell cultures starting from explants obtained from in vitro germinated seedlings. Isolation of protoplasts from plant cell suspension cultures and regeneration of plants via organogenesis and somatic embryogenesis are also presented. PMID:23073877

Moscatiello, Roberto; Baldan, Barbara; Navazio, Lorella

2013-01-01

86

Fifty percent tissue culture infective dose assay for determining the titer of infectious human herpesvirus 8.  

PubMed

We have developed a human herpesvirus 8 (HHV-8) 50% tissue culture infective dose (TCID50) assay using the T1H6-DC-SIGN cell line. Infection of T1H6-DC-SIGN cells with HHV-8 induces expression of ?-galactosidase, which was used to determine TCID50 levels. Validation of TCID50 values was performed by immunofluorescence assay of HHV-8 infection of immature dendritic cells at various TCID50 doses. PMID:23554189

Nadgir, Sagar V; Hensler, Heather R; Knowlton, Emilee R; Rinaldo, Charles R; Rappocciolo, Giovanna; Jenkins, Frank J

2013-04-03

87

Culture of Goblet Cells.  

National Technical Information Service (NTIS)

The invention encompasses isolation, culture and characterization of goblet cells in vitro form mammalian conjuctiva. Goblet cells can be cultured from conjunctiva of such mammals as, e.g., humans, rats, mice, rabbits and the like. In another aspect of th...

D. A. Dartt J. D. Rios M. A. Shatos

2001-01-01

88

Assay methods for antihepatotoxic activity using peroxide-induced cytotoxicity in primary cultured hepatocytes1.  

PubMed

Conditions were investigated to devise IN VITRO assay methods for antihepatotoxic activity using peroxide-induced damage in primary cultured rat liver cells. Utilizing linoleic acid peroxide, benzoyl peroxide, cumene hydroperoxide and adenosine diphosphate/Fe (3+), satisfactory assay procedures were established. Some natural products known to exert liver-protective effects IN VIVO were screened to reveal that glycyrrhetinic acid, glycyrrhizin, cynarin, silybin and desoxypodophyllotoxin showed similar antihepatotoxic activity in these four assay methods. PMID:17340401

Kiso, Y; Kato, O; Hikino, H

1985-02-01

89

A simple quantitative procedure using monolayer cultures for cytotoxicity assays (HTD\\/NR90)  

Microsoft Academic Search

Summary A sensitive quantitative procedure for assaying viable cells in monolayer cultures is described. The two-component test involves (a) microscopic screening for morphological alterations after an experimental protocol for cytotoxicity studies and (b) quantitation of surviving cells by incubation with the supravital dye neutral red, followed by colorimetric analysis of the dye extracted from the lysosomes of the viable cells.

Ellen Borenfreund; James A. Puerner

1985-01-01

90

A sensitive real-time PCR based assay to estimate the impact of amino acid substitutions on the competitive replication fitness of human immunodeficiency virus type 1 in cell culture.  

PubMed

Fixation of mutations in human immunodeficiency virus type 1 (HIV-1), such as those conferring drug resistance and immune escape, can result in a change in replication fitness. To assess these changes, a real-time TaqMan PCR detection assay and statistical methods for data analysis were developed to estimate sensitively relative viral fitness in competitive viral replication experiments in cell culture. Chimeric viruses with the gene of interest in an HIV-1NL4-3 backbone were constructed in two forms, vifA (native vif gene in NL4-3) and vifB (vif gene with six synonymous nucleotide differences from vifA). Subsequently, mutations of interest were introduced into the chimeric viruses in NL4-3VifA backbones, and the mutants were competed against the chimera with the isogenic viral sequence in the NL4-3VifB backbone in cell culture. In order to assess subtle fitness differences, culture supernatants were sampled longitudinally, and the viruses differentially quantified using vifA- and vifB-specific primers in real-time PCR assays. Based on an exponential net growth model, the growth rate of each virus was determined and the fitness cost of the mutation(s) distinguishing the two viruses represented as the net growth rate difference between the mutant and the native variants. Using this assay, the fitness impact of eight amino acid substitutions was quantitated at highly conserved sites in HIV-1 Gag and Env. PMID:23201292

Liu, Yi; Holte, Sarah; Rao, Ushnal; McClure, Jan; Konopa, Philip; Swain, J Victor; Lanxon-Cookson, Erinn; Kim, Moon; Chen, Lennie; Mullins, James I

2012-11-29

91

Adaptation of a sandwich enzyme-linked immunosorbent assay to determine the concentration of bovine leukemia virus p24 and optimal conditions for p24 expression in short-term cultures of peripheral blood mononuclear cells.  

PubMed

Bovine leukemia virus (BLV) is a common retroviral infection of cattle. Infection is accompanied by integration of BLV into the host cell genome and is persistent for the life of the individual as is the presence of anti-BLV antibodies. Lymphosarcoma occurs in a small fraction of infected adult individuals but otherwise there is little or no associated disease. Viremia is undetectable, however, BLV is expressed readily once infected cells are cultured in vitro. A sandwich enzyme-linked immunosorbent assay (sELISA) was optimized, using murine monoclonal antibodies, to quantify the major internal structural protein (p24) produced in short-term cultures of peripheral blood mononuclear cells (PBMCs). Optimal production of BLV p24 was achieved utilizing RPMI supplemented with 10% fetal bovine serum (FBS), pH 7, and 5 x 10(6) cells per ml. Cultures were terminated at 24 h. The sELISA was linear between 30 and 900 ng/ml and the limit of detection was 1.2 ng/ml. At three concentrations of p24, intra- and inter-assay coefficients of variation (CV) varied between 9.2 and 13.3 and 5.1 and 12.9%, respectively. PMID:12821198

van den Heuvel, M; Portetelle, D; Jefferson, B; Jacobs, R M

2003-07-01

92

Uncertainty analysis of cell counting by metabolic assays  

NASA Astrophysics Data System (ADS)

Cell counting is a fundamental procedure in living cell culture-based experiments and protocols in which the cell number quantification is required. The number of cells is one of the parameters necessary to investigate several cell culture features requiring to be monitored as function of time, such as cell viability, proliferation, growth, fitness and metabolism. Aim of this paper is contributing to declare a comprehensive uncertainty budget for cell counting through metabolic assays according to the EURACHEM/CITAC Guide Quantifying Uncertainty in Analytical Measurement.

Divieto, C.; Revel, L.; Sassi, G.; Sassi, M. P.

2013-09-01

93

Use of intracellular pH and annexin-V flow cytometric assays to monitor apoptosis and its suppression by bcl-2 over-expression in hybridoma cell culture.  

PubMed

Accurate identification and quantitation of apoptosis is essential for developing efficient strategies for optimisation of culture viability and productivity in cell lines of industrial significance. We have examined the possibility of using carboxy-seminaphthorhodafluor-1-acetoxymethylester (carboxy SNARF-1-AM), a pH sensitive fluoroprobe and FITC-labelled annexin V (AV), a probe specific to phosphatidylserine exposed on the surface of apoptotic cells, to monitor apoptosis and to determine the relationship between intracellular pH (pHi), apoptosis and cell cycle in hybridoma cells. Temporal changes in the distribution of proliferative capacity (S phase), metabolic activity (pHi), and cell death population dynamics were effectively and reliably determined using flow cytometry. Intracellular acidification was shown to precede the occurrence of apoptosis during batch culture and after treatment with campothecin, staurosporine and under adverse bioreactor conditions such as glutamine deprivation and oxygen deficiency. These results showed that the decrease in pHi can be used as an indicator of cellular deterioration and cell death. AV in combination with propidium iodide permitted the identification of viable, transient apoptotic and necrotic cells in heterogeneous cultures of control (PEF) cells. Hybridoma cells over-expressing bcl-2 were protected from intracellular acidification and phosphatidylserine exposure, which was associated with the suppression of apoptosis in these cells. A decrease in pHi was apparent even before the accumulation of the normally acidic G1 phase and the development of a sub-G1 region, characteristic of apoptotic cell behaviour. The pHi assay can therefore be used as a tool to predict future cell culture performance. reserved. PMID:9894897

Ishaque, A; Al-Rubeai, M

1998-12-01

94

Mammalian Cell Culture Simplified.  

ERIC Educational Resources Information Center

|A tissue culture experiment that does not require elaborate equipment and that can be used to teach sterile technique, the principles of animal cell line maintenance, and the concept of cell growth curves is described. The differences between cancerous and normal cells can be highlighted. The procedure is included. (KR)|

Moss, Robert; Solomon, Sondra

1991-01-01

95

Mutation assays involving blood cells that metabolize toxic substances  

DOEpatents

The present invention pertains to a line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity). Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. The invention also includes mutation assays using these cells, and other cells with similar characteristics. 3 figs.

Crespi, C.L.; Thilly, W.G.

1999-08-10

96

Assessing nanoparticle toxicity in cell-based assays: influence of cell culture parameters and optimized models for bridging the in vitro-in vivo gap.  

PubMed

The number of newly engineered nanomaterials is vastly increasing along with their applications. Despite the fact that there is a lot of interest and effort is being put into the development of nano-based biomedical applications, the level of translational clinical output remains limited due to uncertainty in the toxicological profiles of the nanoparticles (NPs). As NPs used in biomedicines are likely to directly interact with cells and biomolecules, it is imperative to rule out any adverse effect before they can be safely applied. The initial screening for nanotoxicity is preferably performed in vitro, but extrapolation to the in vivo outcome remains very challenging. In addition, generated in vitro and in vivo data are often conflicting, which consolidates the in vitro-in vivo gap and impedes the formulation of unambiguous conclusions on NP toxicity. Consequently, more consistent and relevant in vitro and in vivo data need to be acquired in order to bridge this gap. This is in turn in conflict with the efforts to reduce the number of animals used for in vivo toxicity testing. Therefore the need for more reliable in vitro models with a higher predictive power, mimicking the in vivo environment more closely, becomes more prominent. In this review we will discuss the current paradigm and routine methods for nanotoxicity evaluation, and give an overview of adjustments that can be made to the cultivation systems in order to optimise current in vitro models. We will also describe various novel model systems and highlight future prospects. PMID:23877583

Joris, Freya; Manshian, Bella B; Peynshaert, Karen; De Smedt, Stefaan C; Braeckmans, Kevin; Soenen, Stefaan J

2013-07-23

97

Quantification ofDehalospirillum multivoransin Mixed-Culture Biofilms with an Enzyme-Linked Immunosorbent Assay  

Microsoft Academic Search

A fast, highly selective and sensitive method to quantify specific biomasses in mixed-culture biofilms is described. It consists of detachment of a biofilm from its support material, resolution of the detached biofilm flocs in order to separate the enclosed cells and antigens, and quantification of specific biomass by an enzyme-linked immunosorbent assay. Quantification of microbial biomass is an important factor

PETRA BAUER-KREISEL; MARTINA EISENBEIS; ANDHEIDRUN SCHOLZ-MURAMATSU

1996-01-01

98

HUMN project: detailed description of the scoring criteria for the cytokinesis-block micronucleus assay using isolated human lymphocyte cultures  

Microsoft Academic Search

Criteria for scoring micronuclei and nucleoplasmic bridges in binucleated cells in the cytokinesis-block micronucleus assay for isolated human lymphocyte cultures are described in detail. Morphological characteristics of mononucleated cells, binucleated cells, and multinucleated cells as well as necrotic and apoptotic cells and nuclear buds are also described. These criteria are illustrated by a series of schematic diagrams as well as

M. Fenech; W. P. Chang; M. Kirsch-Volders; N. Holland; S. Bonassi; E. Zeiger

2003-01-01

99

Effect of heat stress and bezafibrate on mitochondrial beta-oxidation: comparison between cultured cells from normal and mitochondrial fatty acid oxidation disorder children using in vitro probe acylcarnitine profiling assay.  

PubMed

Hyperpyrexia occasionally triggers acute life-threatening encephalopathy-like illnesses, including influenza-associated encephalopathy (IAE) in childhood, and can be responsible for impaired fatty acid beta-oxidation (FAO). In this regard, patients with impaired FAO may be more susceptible to febrile episodes. The effects of heat stress and a hypolipidemic drug, bezafibrate, on mitochondrial FAO were investigated using cultured cells from children with FAO disorders and from normal controls, using an in vitro probe acylcarnitine (AC) profiling assay. Fibroblasts were incubated in medium loaded with unlabelled palmitic acid for 96 h at 37 and 41 degrees C, with or without bezafibrate. AC profiles in culture medium were analyzed by electrospray ionization tandem mass spectrometry. Heat stress, introduced by 41 degrees C, significantly increased acetylcarnitine (C2) but slightly decreased the other acylcarnitines (ACs) in controls and medium-chain acyl-CoA dehydrogenase (MCAD)-deficient cells. On the other hand, in very long-chain acyl-CoA dehydrogenase (VLCAD)-deficient cells, accumulation of long-chain ACs were enhanced at 41 degrees C, compared with that at 37 degrees C. In contrast, bezafibrate decreased long-chain ACs with significant increase of C2 in both control and VLCAD-deficient cells at 37 degrees C. These data suggest that heat stress specifically inhibits long-chain FAO, whereas bezafibrate recovers the impaired FAO. Our approach is a simple and promising strategy to evaluate the effects of heat stress or therapeutic drugs on mitochondrial FAO. PMID:19589653

Li, Hong; Fukuda, Seiji; Hasegawa, Yuki; Kobayashi, Hironori; Purevsuren, Jamiyan; Mushimoto, Yuichi; Yamaguchi, Seiji

2009-07-08

100

Soft agarose culture human tumour colony forming assay for drug sensitivity testing: [3H]-thymidine incorporation vs colony counting.  

PubMed Central

In vitro drug sensitivity testing, both by optical colony counting and by a [3H]-TdR incorporation assay, was performed on human tumour cells proliferating in soft agar cultures. Cells from two different human tumour cell lines, 5 different human tumour xenografts, and 94 different primary human tumour specimens of various histologic types were studied. Regression analysis comparing the results of the colony counting assay and the [3H]-TdR assay revealed good to excellent correlations between the two assay endpoints for quantitating the effect of in vitro anticancer drug exposure for a large number of different agents. The presence of pre-existing tumour cell aggregates complicates the performance of the optical colony counting assay. The [3H]-TdR incorporation assay is more sensitive and reproducible than the colony counting assay when performed on samples containing a large number of initially seeded tumour cell aggregates.

Jones, C. A.; Tsukamoto, T.; O'Brien, P. C.; Uhl, C. B.; Alley, M. C.; Lieber, M. M.

1985-01-01

101

Cell senescence culturing methods.  

PubMed

Development of therapeutic approaches that slow or ablate the adverse physiological and pathological changes associated with aging has been considered as an important goal for gerontological research. As cellular senescence is characterized as the basis for aging in organisms, culturing and subculturing of normal human diploid fibroblasts to mimic the in vivo aging processes have been developed as major methods to investigate molecular events involved in aging. It has been established that normal human diploid fibroblasts can proliferate in culture for only finite periods of time. There are many ways to study aging in vitro. In this chapter, we will discuss some of the basic laboratory procedures for cell senescence culturing methods. PMID:23929093

Chen, Huaping; Li, Yuanyuan; Tollefsbol, Trygve O

2013-01-01

102

A Biochemical Assay for Acetylcholinesterase Activity in PC12 Cells  

NSDL National Science Digital Library

This lab describes two biochemical assays: One for measuring acetylcholinesterase activity and one for measuring protein concentration. Students learn how to manipulate small-volume samples, use a standard spectrophotometer or a microplate reader spectrophotometer, construct a standard curve, and normalize data. The lab is intended to be used in conjunction with a cell culture lab in which PC12 cells are exposed to various agents that influence their phenotypic state.

Paul J. Schwartz (University of Medicine and Dentistry of New Jersey;Department of Neurological Surgery REV); Jay A. Blundon (Rhodes College;Department of Biology REV); Elizabeth M. Adler (American Association for the Advancement of Science;Science's STKE REV)

2007-07-10

103

Perfusion Based Cell Culture Chips  

Microsoft Academic Search

\\u000a Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium\\u000a composition, long term unattended cultures and tissue like structuring of the cultures. However, as this chapter illustrates,\\u000a many issues remain to be identified regarding perfusion cell culture

A. Heiskanen; J. Emnéus; M. Dufva

2010-01-01

104

Perfusion Based Cell Culture Chips  

NASA Astrophysics Data System (ADS)

Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers.

Heiskanen, A.; Emnéus, J.; Dufva, M.

105

Assay method for antihepatotoxic activity using galactosamine-induced cytotoxicity in primary-cultured hepatocytes.  

PubMed

Conditions were investigated to devise an in vitro assay method for antihepatotoxic activity using galactosamine-produced injury in primary-cultured mouse and rat liver cells. Employing 1.5-h preincubated hepatocytes prepared from rats, which were much more sensitive to the hepatotoxin, a satisfactory assay procedure was achieved. Some natural products known to exert liver-protective effects in vivo were subjected to screening by this in vitro assay method to reveal that cynarin, desoxypodophyllotoxin, glycyrrhetinic acid, glycyrrhizin, picroside II, and silybin possessed significant antihepatotoxic activity. The described assay method may be useful for primary screening of antihepatotoxic activity of materials of plant origin. The assay method has a number of advantages including the ability to dispose numerous samples at one time at a low cost, the requirement of small sample sizes, little variation, and good reproducibility of results. PMID:6677713

Kiso, Y; Tohkin, M; Hikino, H

106

Cell-based bioluminescence screening assays.  

PubMed

Drug screening is an essential and widely used technique for drug discovery in various biomedical fields notably in oncology. Here we describe a functional screening assay based on the bioluminescence detection of a secreted luciferase for monitoring cell viability of cancer cells in a high-throughput format. This assay allows the screening of large libraries comprising thousands of compounds and the identification of potential anticancer molecules in a rapid, facile, and cost-effective manner. PMID:24166378

Amante, Romain J; Badr, Christian E

2014-01-01

107

Effects of Multivitamins and Known Teratogens on Chick Cardiomyocytes Micromass Culture Assay  

PubMed Central

Objective(s): This study aimed to find out whether the chick cardiomyocyte micromass (MM) system could be employed to predict the teratogenecity of common environmental factors. Different multivitamins and over the counter drugs were used in this study. Materials and Methods: White Leghorn 5-day-old embryo hearts were dissected and trypsinized to produce a cardiomyocyte cell suspension in Dulbecco's Modified Eagle's Medium. The cultures were incubated at 370C in 5% CO2 in air, and observations were made at 24, 48 and 144 hr, for the detection of cell beating. Cellular viability was assessed using the resazurin assay and cell protein content was assessed by the kenacid blue assay. It was observed that while not affecting total cell number folic acid, vitamin C, sodium fluoride and ginseng did not significantly reduced cell activity and beating. However cadmium chloride significantly reduced the beating, cell viability and cell protein content in micromass cultures. Results: The results demonstrate the potential of the chick cardiomyocyte MM culture assay to identify teratogens/embryotoxins that alter morphology and function, which may result in either teratogenic outcome or cytotoxicity. Conclusion: This could form part of a screen for developmental toxicity related to cardiac function.

Memon, Samreen; Pratten, Margaret

2013-01-01

108

Human Cell Chips: Adapting DNA Microarray Spotting Technology to Cell-Based Imaging Assays  

Microsoft Academic Search

Here we describe human spotted cell chips, a technology for determining cellular state across arrays of cells subjected to chemical or genetic perturbation. Cells are grown and treated under standard tissue culture conditions before being fixed and printed onto replicate glass slides, effectively decoupling the experimental conditions from the assay technique. Each slide is then probed using immunofluorescence or other

Traver Hart; Alice Zhao; Ankit Garg; Swetha Bolusani; Edward M. Marcotte; Joanna Mary Bridger

2009-01-01

109

Replication of cultured lung epithelial cells  

SciTech Connect

The authors have investigated the conditions necessary to support replication of lung type 2 epithelial cells in culture. Cells were isolated from mature fetal rabbit lungs (29d gestation) and cultured on feeder layers of mitotically inactivated 3T3 fibroblasts. The epithelial nature of the cells was demonstrated by indirect immunofluorescent staining for keratin and by polyacid dichrome stain. Ultrastructural examination during the first week showed that the cells contained myofilaments, microvilli and lamellar bodies (markers for type 2 cells). The following changes were observed after the first week: increase in cell size; loss of lamellar bodies and appearance of multivesicular bodies; increase in rough endoplasmic reticulum and golgi; increase in tonafilaments and well-defined junctions. General cell morphology was good for up to 10 wk. Cells cultured on plastic surface degenerated after 1 wk. Cell replication was assayed by autoradiography of cultures exposed to (/sup 3/H)-thymidine and by direct cell counts. The cells did not replicate during the first week; however, between 2-10 wk the cells incorporated the label and went through approximately 6 population doublings. They have demonstrated that lung alveolar epithelial cells can replicate in culture if they are maintained on an appropriate substrate. The coincidence of ability to replicate and loss of markers for differentiation may reflect the dichotomy between growth and differentiation commonly observed in developing systems.

Guzowski, D.; Bienkowski, R.

1986-03-05

110

21 CFR 864.7100 - Red blood cell enzyme assay.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Red blood cell enzyme assay. 864.7100 Section 864.7100...Packages § 864.7100 Red blood cell enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used to measure...

2013-04-01

111

Cell cycle analysis of primary sponge cell cultures.  

PubMed

Proliferation of sponge cells is generally measured via cell counts or viability assays. However, more insight into the proliferative state of a sponge cell population can be obtained from the distribution of the cells over the different phases of the cell cycle. Cell cycle distribution of sponge cells was measured via flow cytometry after staining the DNA with propidium iodide. The five sponges studied in this paper all showed a large fraction of cells in G1/G0 compared to G2/M and S, indicating that cells were not actively dividing. In addition, some sponges also showed a large apoptotic fraction, indicating cell death. Additional apoptosis measurements, based on caspase activity, showed that harvesting and dissociation of sponge tissue to initiate a primary cell culture was directly correlated with an increase in apoptotic cells. This indicates that for the development of cell cultures, more attention should be given to harvesting, dissociation, and quality of starting material. Finally, cultivation conditions used were ineffective for proliferation, since after 2 d of cultivating Haliclona oculata cells, most cells shifted towards the apoptotic fraction, indicating that cells were dying. For development of in vitro sponge cell cultures, flow cytometric cell cycle analysis is a useful method to assess the proliferative state of a sponge cell culture and can be used to validate improvements in harvesting and dissociation, to select sponges with good proliferative capacities and to study the influence of culture conditions for stimulating cell growth. PMID:21416188

Schippers, Klaske J; Martens, Dirk E; Pomponi, Shirley A; Wijffels, René H

2011-03-17

112

Fluorometric assay for red blood cell antibodies  

SciTech Connect

A fluorometric assay is described for the detection of red blood cell antibodies. The assay reveals as little as 600 molecules of bound, fluoroesceinated rabbit anti-human IgG antibodies per erythrocyte. Eleven patients with possible autoimmune erythrocyte disorder and negative direct antiglobulin test were studied by the fluorometric assay. The outcome of the fluorometric assay was compared with that of the human allogeneic rosette test. Results obtained by the two methods were in complete agreement. Five of the patients were shown to possess unexpectedly high levels of erythrocyte-bound IgG in spite of a negative, direct antiglobulin test. These findings and the validity of the fluorometric assay are discussed.

Schreiber, A.B.; Lambermont, M.; Strosberg, A.D.; Wybran, J.

1981-03-01

113

Enzyme?Linked Immunosorbent Assay Detection of Trichothecenes Produced by the Bioherbicide Myrothecium verrucaria in Cell Cultures, Extracts, and Plant Tissues  

Microsoft Academic Search

A rapid technique for trichothecene detection was needed in screening tests of the potential bioherbicide Myrothecium verrucaria (MV), in order to select strains, mutants, or formulations that were void of or that possessed low amounts of these undesirable mycotoxin compounds. Commercially available enzyme?linked immunosorbent assay (ELISA) plates for trichothecene detection, possessing cross?reactivity with several trichothecene mycotoxins (e.g., verrucarin A, and

Robert E. Hoagland; Mark A. Weaver; C. Douglas Boyette

2008-01-01

114

Quantum Dot-Based Cell Motility Assay  

SciTech Connect

Because of their favorable physical and photochemical properties, colloidal CdSe/ZnS-semiconductor nanocrystals (commonly known as quantum dots) have enormous potential for use in biological imaging. In this report, we present an assay that uses quantum dots as markers to quantify cell motility. Cells that are seeded onto a homogeneous layer of quantum dots engulf and absorb the nanocrystals and, as a consequence, leave behind a fluorescence-free trail. By subsequently determining the ratio of cell area to fluorescence-free track area, we show that it is possible to differentiate between invasive and noninvasive cancer cells. Because this assay uses simple fluorescence detection, requires no significant data processing, and can be used in live-cell studies, it has the potential to be a powerful new tool for discriminating between invasive and noninvasive cancer cell lines or for studying cell signaling events involved in migration.

Gu, Weiwei; Pellegrino, Teresa; Parak Wolfgang J; Boudreau,Rosanne; Le Gros, Mark A.; Gerion, Daniele; Alivisatos, A. Paul; Larabell, Carolyn A.

2005-06-06

115

A comparison of colorimetric and DNA quantification assays for the assessment of meniscal fibrochondrocyte proliferation in microcarrier culture.  

PubMed

We have developed and refined a rapid, reliable method for the evaluation of attachment and proliferation of ovine meniscal chondrocytes in microcarrier culture. Assays measuring both mitochondrial activity, using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and MTS [3-(4,5-dimethylthiazol-2-yl)5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium], and DNA synthesis with a PicoGreen assay were compared. The MTT assay was the most sensitive at lower cell concentrations and enabled accurate assessment of cell proliferation over 14 day culture. PMID:16231215

Pabbruwe, Moreica B; Stewart, Karina; Chaudhuri, Julian B

2005-10-01

116

Improved transfection efficiency of cultured human cells  

Microsoft Academic Search

We simultaneously tested the transfection efficiency of NT2\\/D1 and HeLa cells with Lipofectamine™ (Life Technologies) and Effectene™ (Qiagen) transfection reagents using the pCH110 eukaryotic assay vector, which contains the lacZ reporter gene. Under our culture conditions for NT2\\/D1 and HeLa cells, Effectene™ transfection efficiency could be augmented by simply increasing the amount of plasmid DNA 1.5–3 times above the recommended

Gordana Nikcevic; Natasa Kovacevic-Grujicic; Milena Stevanovic

2003-01-01

117

The application of bioluminescence assay with culturing for evaluating quantitative disinfection performance.  

PubMed

Various methods, including bioluminescence assay, were investigated regarding their suitability for quantitatively evaluating the disinfection performance. Although bioluminescence assay itself has been widely reported as a rapid, easy and suitable method for analyzing live microorganisms, the limited sensitivity of its measurement (approximately 10(3)-10(4)cells/assay vial), which is insufficient for disinfection study, requires further study. Among three methods (amplifying by enzymatic method, membrane filtration, and amplification by culturing) examined for increasing the detection sensitivity, amplification by culturing showed the best performance as Escherichia coli was employed as an indicating microorganism. Even with a short culturing time of 4h, the detection limit of E. coli measurement was successfully improved 200-fold, and the analytical results were not dependent upon the state of E. coli growth (stationary state with E. coli stock suspension vs. growth state with E. coli). In addition, the analytical integrity of bioluminescence assay with culturing was further demonstrated in comparison with spread plate method as free chlorine and UV irradiation were employed in the disinfection study. PMID:17229450

Cho, Min; Yoon, Jeyong

2007-01-16

118

Traditional and emerging methods for analyzing cell activity in cell culture  

Microsoft Academic Search

The selection of appropriate techniques to assay for markers of cell activity is important for obtaining optimal results in cell culture-based research. This paper is intended as a guide to many of the assays currently available and new techniques that have been recently introduced in the literature. This paper addresses both manual assay techniques, including the use of hemocytometers, phase

Nathanial T. Stewart; Katherine M. Byrne; Howard L. Hosick; Janet L. Vierck; Michael V. Dodson

2000-01-01

119

In Vivo Assay for Tumor Cell Invasion  

PubMed Central

Summary We describe an in vivo invasion assay that enables the collection of invasive cells from the primary tumor. In addition to determination of the endogenous, unstimulated invasive properties of cells in vivo, the assay can take advantage of the chemotactic properties of cancer cells. Microneedles are filled with a mixture of extracellular matrix components such as Matrigel with or without a chemoattractant such as EGF, and then introduced into the primary tumor of a rat or mouse that is generated either by orthotopic injection of carcinoma cell lines or by a transgene such as polyoma Middle T. Over the course of 4 h the invasive cell population enters the needles while the animal is kept under anesthesia. At the end of the collection time, the invasive cells are extruded from the microneedles and can be analyzed in terms of the number and type of cells that invade in response to defined stimuli. By including pharmacological inhibitors in the needle, signaling pathways contributing to in vivo invasion can also be identified. This assay leads to a better understanding of the cell types and signaling involved in the tumor microenvironment, and has the potential to be applied to a variety of in vivo models.

Hernandez, Lorena; Smirnova, Tatiana; Wyckoff, Jeffrey; Condeelis, John; Segall, Jeffrey E.

2010-01-01

120

Cell Culture Models and Methods  

Microsoft Academic Search

\\u000a This chapter reviews methods to harvest and culture several different cell systems commonly employed in cardiac electrophysiology\\u000a research. The cell systems covered fall into three main categories: (1) primary cell culture; (2) cell lines; and (3) stem\\u000a cell-derived cardiomyocytes. Each cell system has its own set of advantages and disadvantages. Often the best choice depends\\u000a on the question an investigator

Alena Nikolskaya; Vinod Sharma

121

Comparison of standard culture methods, a shell vial assay, and a DNA probe for the detection of herpes simplex virus.  

PubMed Central

A nonradioactive, biotinylated herpes simplex virus (HSV) DNA probe, a shell vial (rabbit kidney cell) culture assay enhanced by a direct fluorescent (HSV monoclonal)-antibody stain at 16 to 20 h postinoculation, and conventional tube cultures with confirmation via HSV-specific (polyclonal antibody) immunoperoxidase assay were compared for 199 specimens. The predictive values of the positive results were 54.5% for the probe, 95.9% for the shell vial assay, and 100% for the conventional culture methods, while the predictive values of the negative tests were 68.1, 84.0, and 98.4%, respectively. We conclude that the DNA probe (sensitivity, 24.5%; specificity, 88.3%) and the shell vial assay (sensitivity, 66.2%; specificity, 98.4%) cannot be substituted for conventional tube culture techniques (sensitivity, 97.1%; specificity, 100%) in the routine identification of HSV in our laboratory.

Seal, L A; Toyama, P S; Fleet, K M; Lerud, K S; Heth, S R; Moorman, A J; Woods, J C; Hill, R B

1991-01-01

122

Development of a high-throughput antiviral assay for screening inhibitors of chikungunya virus and generation of drug-resistant mutations in cultured cells.  

PubMed

Chikungunya virus (CHIKV) is a mosquito-borne Alphavirus that has already infected millions of people in recent large-scale epidemics in Africa, the islands of the Indian Ocean, South and Southeast Asia, and northern Italy. The infection is still ongoing in many countries, such as India. Although the fatal rate is approximately 0.1% in the La Réunion outbreak, it causes painful arthritis-like symptoms that can last for months or even years. Currently, neither vaccine nor approved antiviral therapy exists to protect humans from chikungunya infection. Therefore, there is an urgent unmet medical need for the development of antiviral drugs for pre-exposure prophylaxis and/or treatment of chikungunya infections. In this chapter, we describe a fully validated ATP/luminescence assay that is effective for high-throughput screening of CHIKV inhibitors. Protocols for growing CHIKV stocks and generating drug-resistant viral variants for modes of action studies of compounds are also described. PMID:23821286

Gong, Edwin Yunhao; Bonfanti, Jean-François; Ivens, Tania; Van der Auwera, Marijke; Van Kerckhove, Barbara; Kraus, Guenter

2013-01-01

123

Dynamic single cell culture array  

Microsoft Academic Search

We demonstrate perfusion culture of arrays of individually trapped cells with dynamic microfluidic control of cellular environment, high maintenance of cell isolation, and low cell death. Hydrodynamically trapped cells were shown to adhere and divide at a comparable rate to cells grown randomly on the same glass substrate. This technique will be useful in quantitative single cell studies that require

Dino Di Carlo; Liz Y. Wu; Luke P. Lee

2006-01-01

124

Expanding the Available Assays: Adapting and Validating In-Cell Westerns in Microfluidic Devices for Cell-Based Assays  

PubMed Central

Abstract Microfluidic methods for cellular studies can significantly reduce costs due to reduced reagent and biological specimen requirements compared with many traditional culture techniques. However, current types of readouts are limited and this lack of suitable readouts for microfluidic cultures has significantly hindered the application of microfluidics for cell-based assays. The In-Cell Western (ICW) technique uses quantitative immunocytochemistry and a laser scanner to provide an in situ measure of protein quantities in cells grown in microfluidic channels of arbitrary geometries. The use of ICWs in microfluidic channels was validated by a detailed comparison with current macroscale methods and shown to have excellent correlation. Transforming growth factor-?–induced epithelial-to-mesenchymal transition of an epithelial cell line was used as an example for further validation of the technique as a readout for soluble-factor-based assays performed in high-throughput microfluidic channels. The use of passive pumping for sample delivery and laser scanning for analysis opens the door to high-throughput quantitative microfluidic cell-based assays that integrate seamlessly with existing high-throughput infrastructure.

Paguirigan, Amy L.; Puccinelli, John P.; Su, Xiaojing

2010-01-01

125

Human Primary Lung Endothelial Cells in Culture  

PubMed Central

Pulmonary endothelial functions are critical to maintain the low pressure of the pulmonary circulation and effective diffusion capacity of the lung. To investigate pulmonary endothelial cell biology in healthy or diseased lungs, we developed methods to harvest and culture pure populations of primary pulmonary arterial endothelial cells and microvascular endothelial cells from human lung explanted at time of transplantation or from donor lungs not used in transplantation. The purity and characteristics of cultured endothelial cells is ascertained by morphologic criteria using phase contrast and electron microscopy; phenotypic expression profile for endothelial specific proteins such as endothelial nitric oxide synthase, platelet/endothelial cell adhesion molecule, and von Willbrand factor; and endothelial function assays such as Dil-acetylated low-density lipoprotein uptake and tube formation. This detailed method provides researchers with the ability to establish cells for molecular, genetic, and biochemical investigation of human pulmonary vascular diseases.

Xu, Weiling; Mavrakis, Lori; Aldred, Micheala A.; Asosingh, Kewal; Erzurum, Serpil C.

2012-01-01

126

Oxygen Control For Bioreactors And In-vitro Cell Assays  

NASA Astrophysics Data System (ADS)

Dissolved oxygen (DO) is an important parameter in biomedical and cell-culture applications. Several studies have found cell survival and function to be intimately linked to oxygen concentration. Laminar flow, as observed in microfluidic devices, provides an ideal environment to manipulate and control concentration gradients. In this paper we demonstrate the first characterization of integrated fluorescence-based oxygen sensors for DO measurement within a cell-culture bioreactor device. Solid-state PtOEPK/PS sensor patterns were integrated into the PDMS-based bioreactor and calibrated for detection of DO concentration with a superimposed layer of collagen and Ishikawa human endometrial cancer cells. The sensor signal of the layer subjacent to the cells was found to follow a Stern-Volmer model and the intensity ratio was measured to I0/I100 = 3.9 after 3 days in culture. The device provides a novel tool for the control and spatially-resolved measurement of oxygen levels in cellular assays and cell-culture applications.

Nock, V.; Blaikie, R. J.; David, T.

2009-07-01

127

Cell death pattern of a varicose vein organ culture model.  

PubMed

The study aimed to investigate the viability of a varicose vein (VV) organ culture model by assessing cell death pattern. To assess pattern of cell death with time, VV organ cultures were incubated for up to 14 days with regular medium changed. To assess viability, cell death of VV organ cultures treated with sodium azide and their untreated counterparts was assayed. Increased cell death was measured in VV organ cultures from day 0 to 2. Cell death decreased gradually after day 2 and plateaued from day 8 to 14.VV organ cultures treated with sodium azide demonstrated significantly more cell death in tissue (P = 0.001). Cell death measured in cultures treated with sodium azide continued to increase until day 7. In conclusion, this study demonstrated the viability of a VV organ culture model with most cell death occurred within the first two days and then declined to a relatively low level. PMID:23526103

Lim, Chung S; Kiriakidis, Serafim; Paleolog, Ewa M; Davies, Alun H

2013-06-01

128

CONTINUOUS-FLOW ENZYME ASSAY ON A MICROFLUIDIC CHIP FOR MONITORING GLYCEROL SECRETION FROM CULTURED ADIPOCYTES  

PubMed Central

A dual-chip microfluidic platform that coupled perfusion of cultured adipocytes with on-line fluorescence-based enzyme assay was developed to monitor glycerol secretions in real-time from cultured adipocytes. The perfusion cell chip, which could be reversibly sealed to allow reloading of cells and reuse of the chip, was shown by modeling to generate low shear stress on the cells under study. Effluent from the perfusion chip was pumped into an enzyme assay chip for monitoring of secretion from the cells. The on-line enzyme assay had a LOD of 4 ?M glycerol. The temporal resolution of the combined system for detecting changes in glycerol concentration was 90 s. The microfluidic device was used to continuously monitor glycerol secretion from murine 3T3-L1 adipocytes, grown and differentiated on glass cover slips, for at least 2 h. An average basal glycerol concentration of 28 ?M was detected in the effluent. Pharmacological treatment with a ?-adrenergic agonist to stimulate lipolysis evoked a 3-fold increase in glycerol secretion followed by sustained release that was 40% higher than basal concentration. The ability to monitor changes in cellular secretion over time may provide insight into adipocyte metabolism and the dysregulation that occurs with obesity-related disorders.

Clark, Anna M.; Sousa, Kyle M.; Jennings, Colin; MacDougald, Ormond A.; Kennedy, Robert T.

2009-01-01

129

Eosinophil contamination of thioglycollate-elicited peritoneal macrophage cultures skews the functional readouts of in vitro assays.  

PubMed

Thioglycollate-elicited peritoneal cells are a common source of macrophages for various in vitro assays, including stimulation with TLR ligands, cell signaling assays, phagocytosis, toxicology studies, and cytokine/chemokine production. The most common method for enrichment of cultured thioglycollate-elicited peritoneal cells is adherence. However, the presence of other cell types in freshly isolated and cultured thioglycollate-elicited peritoneal cells has not been examined. Here, we demonstrate that thioglycollate-elicited peritoneal cavity contains 55-60% nonmacrophage cells, and even after adherence, there are still 12-20% nonmacrophage cells remaining. Excluding macrophages, eosinophils are the major cell type in the freshly elicited cavity (30-40%). Eosinophils are also the major cell type contaminating in vitro cultures of thioglycollate-elicited peritoneal macrophages. Moreover, the contamination of macrophage cultures by eosinophils significantly diminishes activation of p38 MAPK and the serine threonine kinase Akt and production of proinflammatory cytokines in response to LPS stimulation. Taken together, these data suggest that thioglycollate-elicited peritoneal cells are far more heterogeneous than reported previously. Further, a failure to remove contaminating eosinophils may greatly affect the interpretation of results obtained with cultured thioglycollate-elicited macrophages. Thus, our data indicate that future studies intent on accurately assessing cultured macrophage phenotype and activation require depletion of all cocontaminating cells, especially eosinophils. PMID:22706315

Misharin, Alexander V; Saber, Rana; Perlman, Harris

2012-06-15

130

Eosinophil contamination of thioglycollate-elicited peritoneal macrophage cultures skews the functional readouts of in vitro assays  

PubMed Central

Thioglycollate-elicited peritoneal cells are a common source of macrophages for various in vitro assays, including stimulation with TLR ligands, cell signaling assays, phagocytosis, toxicology studies, and cytokine/chemokine production. The most common method for enrichment of cultured thioglycollate-elicited peritoneal cells is adherence. However, the presence of other cell types in freshly isolated and cultured thioglycollate-elicited peritoneal cells has not been examined. Here, we demonstrate that thioglycollate-elicited peritoneal cavity contains 55–60% nonmacrophage cells, and even after adherence, there are still 12–20% nonmacrophage cells remaining. Excluding macrophages, eosinophils are the major cell type in the freshly elicited cavity (30–40%). Eosinophils are also the major cell type contaminating in vitro cultures of thioglycollate-elicited peritoneal macrophages. Moreover, the contamination of macrophage cultures by eosinophils significantly diminishes activation of p38 MAPK and the serine threonine kinase Akt and production of proinflammatory cytokines in response to LPS stimulation. Taken together, these data suggest that thioglycollate-elicited peritoneal cells are far more heterogeneous than reported previously. Further, a failure to remove contaminating eosinophils may greatly affect the interpretation of results obtained with cultured thioglycollate-elicited macrophages. Thus, our data indicate that future studies intent on accurately assessing cultured macrophage phenotype and activation require depletion of all cocontaminating cells, especially eosinophils.

Misharin, Alexander V.; Saber, Rana; Perlman, Harris

2012-01-01

131

Huanglongbing and psyllid cell cultures  

Technology Transfer Automated Retrieval System (TEKTRAN)

We successfully established cell cultures of the Asian citrus psyllid, Diaphorina citri (Psyllidae: Hemiptera), DcHH-1. The cell culture also supported growth of Candidatus Liberibacter asiaticus. This bacterial pathogen is associated with Huanglongbing, known as citrus greening disease. Research on...

132

Malignant transformation of mammalian cells in culture, including human cells  

SciTech Connect

This overview of the malignant transformation of mammalian cells in culture, including human cells, describes the earliest evidence of spontaneous, virus-induced, and carcinogen-induced transformation. It discusses several systems developed to assay the carcinogen-induced transformation of highly selected infinite life span (established) cell lines as well as finite life span diploid cells. Evidence is presented to support the multistep hypothesis of the process of malignant transformation, and the theoretical requirement for acquisition of an infinite, or greatly extended, life span in culture if a cell is to become malignant is explained in light of the multistep nature of the process. The use of oncogene transfection studies to analyze the number and kinds of changes involved is discussed, with emphasis on studies using human cells. Finally, the results of earlier studies on viral- and carcinogen-induced transformation of mammalian cells (or chicken cells) are reinterpreted in the light of more recent insights into the process of carcinogenesis.

McCormick, J.J.; Maher, V.M. (Michigan State Univ., East Lansing (USA))

1989-01-01

133

Formaldehyde cytotoxicity in three human cell types assessed in three different assays.  

PubMed

International standards for preclinical screening of the cytotoxicity of dental materials so far recommend the use of established cell lines. The aim of this study was to assess the relative susceptibility of human dental pulp fibroblasts (HPF), human buccal epithelial cells (HBE) and HeLa cervix cancer cells exposed to identical cytotoxic challenges. Formaldehyde, which may be released from dental materials such as dental composites, glassionomer cements, and endodontic sealers, was used as test chemical. Cytotoxicity data including dose-response relations and TC(50) values were assessed in three different assays: BrdU incorporation, neutral red uptake and MTT assays. HBE and HPF demonstrated statistically significant lower TC(50) values in both the neutral red and the BrdU assay in comparison to HeLa cells. In the MTT assay no statistically significant differences were observed between the cell types. In the two target-tissue cell types (HPF and HBE) the Neutral Red assay revealed lower TC(50) values in comparison to the BrdU assay. In HeLa cells no statistically significant differences were observed between the assays. In conclusion, the present study confirms that cytotoxicity data obtained by cell culture studies are influenced by both cell culture model and choice of assay. Under identical experimental conditions, human target tissue cells appeared to be more sensitive to formaldehyde toxicity than human HeLa cancer cells. PMID:11812641

Lovschall, H; Eiskjaer, M; Arenholt-Bindslev, D

2002-02-01

134

Detection of hypoxic cells in murine tumors using the comet assay: comparison with a conventional radiobiological assay.  

PubMed

The comet (single-cell electrophoresis) assay has been developed as a method for measuring DNA damage in single cells after irradiation. We have developed our own methods and image analysis system for the comet assay to identify hypoxic fractions. In vitro, we tested our system using a cultured tumor cell line (SCCVII). In vivo, we compared the hypoxic fractions detected by this assay with those determined by the in vivo-in vitro clonogenic assay using two rodent tumors (SCCVII/ C3H, EMT6/KU/balb/c), which exhibit different types of hypoxia: acute and chronic. In vitro, our method could differentiate hypoxic cells from oxic cells, using the parameter of tail moment. In vivo, there were good correlations between the hypoxic fractions determined by the comet assay and by the clonogenic assay, in SCCVII/C3H (r=0.85) and in EMT6/KU/balb/c (r=0.75) tumors. By comparison of the two methods in chronically hypoxic and acutely hypoxic tumors, we further confirmed that the comet assay is clinically useful for estimating hypoxic fractions of solid tumors. PMID:10543261

Shibuya, K; Sasai, K; Xie, X; Utsumi, H; Shibata, T; Hiraoka, M

1999-08-01

135

Neutral red uptake assay for the estimation of cell viability\\/cytotoxicity  

Microsoft Academic Search

The neutral red uptake assay provides a quantitative estimation of the number of viable cells in a culture. It is one of the most used cytotoxicity tests with many biomedical and environmental applications. It is based on the ability of viable cells to incorporate and bind the supravital dye neutral red in the lysosomes. Most primary cells and cell lines

Ana del Peso; Jorge L Zurita; Guillermo Repetto

2008-01-01

136

The animal cell culture collection  

Microsoft Academic Search

Summary  The Animal Cell Culture Collection established by the Advisory Committee and cooperating laboratories at the American Type\\u000a Culture Collection has been described. The description includes procedures and criteria for the acceptance and certification\\u000a of cells, guidelines for future studies, and policies for the selection of cells. The aim of this Collection is to fulfill\\u000a the needs of individual investigators for

C. S. Stulberg; L. L. Coriell; A. J. Kniazeff; J. E. Shannon

1970-01-01

137

KERATINOCYTE CELL-MEDIATED MUTAGENESIS ASSAY: CORRELATION WITH IN VIVO TUMOR STUDIES  

EPA Science Inventory

A murine keratinocyte cell-mediated mutagenesis assay was characterized and examined as an in vitro model system for studying the biotransformation of promutagens/procarcinogens by mouse skin. The assay used living cultured newborn SENCAR keratinocytes for the metabolic activatio...

138

Three-dimensional cell culturing by magnetic levitation.  

PubMed

Recently, biomedical research has moved toward cell culture in three dimensions to better recapitulate native cellular environments. This protocol describes one method for 3D culture, the magnetic levitation method (MLM), in which cells bind with a magnetic nanoparticle assembly overnight to render them magnetic. When resuspended in medium, an external magnetic field levitates and concentrates cells at the air-liquid interface, where they aggregate to form larger 3D cultures. The resulting cultures are dense, can synthesize extracellular matrix (ECM) and can be analyzed similarly to the other culture systems using techniques such as immunohistochemical analysis (IHC), western blotting and other biochemical assays. This protocol details the MLM and other associated techniques (cell culture, imaging and IHC) adapted for the MLM. The MLM requires 45 min of working time over 2 d to create 3D cultures that can be cultured in the long term (>7 d). PMID:24030442

Haisler, William L; Timm, David M; Gage, Jacob A; Tseng, Hubert; Killian, T C; Souza, Glauco R

2013-09-12

139

Quantitative comparison between microfluidic and microtiter plate formats for cell-based assays.  

PubMed

In this paper, we compare a quantitative cell-based assay measuring the intracellular Ca2+ response to the agonist uridine 5'-triphosphate in Chinese hamster ovary cells, in both microfluidic and microtiter formats. The study demonstrates that, under appropriate hydrodynamic conditions, there is an excellent agreement between traditional well-plate assays and those obtained on-chip for both suspended immobilized cells and cultured adherent cells. We also demonstrate that the on-chip assay, using adherent cells, provides the possibility of faster screening protocols with the potential for resolving subcellular information about local Ca2+ flux. PMID:18052343

Yin, Huabing; Pattrick, Nicola; Zhang, Xunli; Klauke, Norbert; Cordingley, Hayley C; Haswell, Steven J; Cooper, Jonathan M

2007-12-06

140

Endosperm Cell and Organ Culture  

Microsoft Academic Search

This chapter describes efforts to culture maize endosperm to enable direct developmental and metabolic\\u000a studies of the cereal endosperm organ without the effects of the maternal plant. First, we describe production\\u000a of endosperm in culture through either central cell fertilization in vitro or through isolation of\\u000a embryo sacs following fertilization in vivo. These techniques have been used to culture cereal endosperm\\u000a but

D. Gruis; H. Guo; Q. Tian; O.-A. Olsen

141

Rat hepatocyte primary cell cultures  

Microsoft Academic Search

Summary  The conditions for obtaining representative, adult rat hepatocyte primary cell cultures were improved such that viable yields\\u000a of 50% of the liver were produced which gave rise to cultures representing 30% of the liver. The survival of the cultures\\u000a in various media was compared revealing that in complex media, particularly containing galactose, survival was improved.

Gary M. Williams; Edilberto Bermudez; Dominick Scaramuzzino

1977-01-01

142

Different responses in transformation of MDCK cells in 2D and 3D culture by v-Src as revealed by microarray techniques, RT-PCR and functional assays  

Microsoft Academic Search

Differentiation and transformation of untransformed and ts-Src-transformed canine kidney MDCK cells in 2D and 3D environment were investigated using microarray technique, RT-PCR, confocal microscopy and functional assays. Activated Src induced epithelial–mesenchymal transition (EMT) in 2D environment followed by translocation of junctional proteins to the cytoplasm, without significant changes in protein expression. In 3D environment untransformed MDCK cells formed cell cysts

Mira Töyli; Linda Rosberg-Kulha; Janne Capra; Jussi Vuoristo; Sinikka Eskelinen

2010-01-01

143

Vero cell assay for rapid detection of Clostridium perfringens enterotoxin.  

PubMed Central

A rapid assay which measured the biological activity of Clostridium perfringens enterotoxin was developed. The method involved the rapid killing of Vero cells by enterotoxin produced by C. perfringens grown in Duncan and Strong sporulation medium. Serial dilutions of toxin were added to Vero cells either in suspension or grown as monolayers in wells of a 96-well cell tissue culture cluster plate. Vital staining of Vero cells with neutral red, followed by extraction of the dye, allowed toxin levels to be determined either visually or by optical density measurements with a micro-ELISA M580 computer program. The toxin produced was confirmed as different from the Vero toxin of Escherichia coli and the alpha and theta toxins of C. perfringens.

Mahony, D E; Gilliatt, E; Dawson, S; Stockdale, E; Lee, S H

1989-01-01

144

Three-dimensional polymer scaffolds for high throughput cell-based assay systems  

Microsoft Academic Search

Many whole cell-based assays in use today rely on flat, two-dimensional (2D) glass or plastic substrates that may not produce results characteristic of in vivo conditions. In this study, a three-dimensional (3D) cell-based assay platform was established by integrating 3D synthetic polymer scaffolds with standard cell culture dishes and multi-well plates. This technology can be used to feasibly modify any

Ke Cheng; Yinzhi Lai; William S. Kisaalita

2008-01-01

145

Aflatoxins in Mammalian Cell Cultures.  

National Technical Information Service (NTIS)

KB and HeLa mammalian tissue culture cells were cultured in the presence of 0.4, 1, and 4 ppm of aflatoxin. The incorporation of labeled uridine into the different RNA components separated by sucrose gradient ultracentrifugation and by methylated albumin ...

R. A. Chung

1968-01-01

146

21 CFR 864.7100 - Red blood cell enzyme assay.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Red blood cell enzyme assay. 864.7100 Section...and Packages § 864.7100 Red blood cell enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used...

2009-04-01

147

21 CFR 864.7100 - Red blood cell enzyme assay.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Red blood cell enzyme assay. 864.7100 Section...and Packages § 864.7100 Red blood cell enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used...

2010-04-01

148

Type and Subtype-Specific Detection of Influenza Viruses in Clinical Specimens by Rapid Culture Assay  

Microsoft Academic Search

A rapid culture assay which allows for the simultaneous typing and subtyping of currently circulating influenza A(H1N1), A(H3N2), and B viruses in clinical specimens was developed. Pools of monoclonal anti- bodies(MAbs)againstinfluenzaAandBvirusesandMAbsHA1-71andHA2-76,obtainedbyimmunizingmice withthedenaturedhemagglutininsubfragmentsHA1andHA2ofinfluenzavirusA\\/Victoria\\/3\\/75,wereusedfor immunoperoxidase staining of antigens in infected MDCK cells. MAb HA1-71 reacted exclusively with influ- enza A viruses of the H3 subtype, while MAb HA2-76 reacted with subtypes H1,

THEDI ZIEGLER; HENRIETTA HALL; ALICIA SANCHEZ-FAUQUIER; WILLIAM C. GAMBLE; J. COX

1995-01-01

149

Screening of maternal sera using a mouse embryo culture assay is not predictive of human embryo development or IVF outcome  

Microsoft Academic Search

Purpose: Maternal serum is commonly added to media used for human IVF but can vary widely in its ability to support the development of human embryos in vitro. The objective of this study was to determine if the screening of maternal serum with a mouse one-cell embryo culture assay would be useful in predicting human embryo development and clinical outcome

Robert N. Clarke; Patricia M. Griffin; John D. Biggers

1995-01-01

150

Cryopreservation of Dedifferentiated Cell Cultures  

Microsoft Academic Search

When Gottlieb Haberlandt made the first efforts to cultivate single isolated plant cells in salt solutions his goal was to\\u000a prove the totipotency of single cells (Haberlandt 1902). The cultivation of isolated plant cells in a chemically defined culture\\u000a medium became possible only after the discovery and application of auxins (Gautheret 1939). Today plant cells as well as tissues\\u000a can

Elke Heine-Dobbernack; Heiko Kiesecker; Heinz Martin Schumacher

151

Translation of a tumor microenvironment mimicking 3D tumor growth co-culture assay platform to high-content screening.  

PubMed

For drug discovery, cell-based assays are becoming increasingly complex to mimic more realistically the nature of biological processes and their diversifications in diseases. Multicellular co-cultures embedded in a three-dimensional (3D) matrix have been explored in oncology to more closely approximate the physiology of the human tumor microenvironment. High-content analysis is the ideal technology to characterize these complex biological systems, although running such complex assays at higher throughput is a major endeavor. Here, we report on adapting a 3D tumor co-culture growth assay to automated microscopy, and we compare various imaging platforms (confocal vs. nonconfocal) with correlating automated image analysis solutions to identify optimal conditions and settings for future larger scaled screening campaigns. The optimized protocol has been validated in repeated runs where established anticancer drugs have been evaluated for performance in this innovative assay. PMID:22923784

Krausz, Eberhard; de Hoogt, Ronald; Gustin, Emmanuel; Cornelissen, Frans; Grand-Perret, Thierry; Janssen, Lut; Vloemans, Nele; Wuyts, Dirk; Frans, Sandy; Axel, Amy; Peeters, Pieter Johan; Hall, Brett; Cik, Miroslav

2012-08-24

152

Automated spectrophotometric assay for cell division regulation in yeast.  

PubMed

A spectrophotometric assay is presented for monitoring the regulation of cell division by the polypeptide alpha-factor in cultures of living cells of Saccharomyces cerevisiae yeast. This assay is simple, automated, and may have wider application in the study of other eucaryotic cells that do not require anchorage for cell growth. The kinetics of absorbance change were monitored continuously over time in yeast cell cultures that were mixed and aerated in cuvettes fitted with top-loading propeller stirrers. The absorbance doubling time. TD(Abs), was identical to the cell number doubling time in the absence of cell division arrest by alpha-factor. alpha-Factor lengthened the TD(Abs) during division arrest. At pH 5.8, 10(5) 381G cells/ml, the Khalf-maximal was 250 +/- 50 nM alpha-factor for the TD(Abs) increase during arrest, with a maximum increase of five-fold. After a period of time the TD(Abs) abruptly shortened. This is defined as the spectrophotometric recovery time (RTspec) and was compared to the time of recovery that is due to the reinitiation of cell division monitored by bud emergence (RTBE). RTBE occurred 40 +/- 5 min prior to RTspec when recovery was spontaneous or was artificially induced by the removal of alpha-factor (pH 5.8, 381G). The difference between RTBE and RTspec was independent of alpha-factor concentration between 0.05 and 1 microM and cell concentration between 1 and greater than or equal to 25 x 10(5) cells/ml (pH 5.8, 381G) but was both pH and cell strain dependent. At pH 5.8 and 2.7 the recovery from arrest occurred by inactivation of alpha-factor. The TD(Abs) increase during arrest appears to be due to an alpha-factor-induced inhibition of net cell mass increase, an effect that has not been reported previously. Evidence is presented that this process is also correlated with the formation of cell projections. PMID:3292275

Moore, S A; Garcia, C V; Gardner, B T; Lester, G A

1988-08-01

153

Comparison of Multiple Passage Integrated Cell Culture-PCR and Cytopathogenic Effects in Cell Culture for the Assessment of Poliovirus Survival in Water  

Microsoft Academic Search

The goal of this study was to determine if a cytopathogenic effects (CPE) cell culture assay and an integrated cell culture\\u000a PCR (ICC-PCR) assay would yield similar or different results when used to assess virus survival in water. Poliovirus type\\u000a 1 was added to dechlorinated tapwater and stored at room temperature (22.5–24°C) for a total of 50 days. Samples were assayed

Madhumita Mahalanabis; Kelly A. Reynolds; Ian L. Pepper; Charles P. Gerba

2010-01-01

154

Isolation of primary mouse trophoblast cells and trophoblast invasion assay.  

PubMed

The placenta is responsible for the transport of nutrients, gasses and growth factors to the fetus, as well as the elimination of wastes. Thus, defects in placental development have important consequences for the fetus and mother, and are a major cause of embryonic lethality. The major cell type of the fetal portion of the placenta is the trophoblast. Primary mouse placental trophoblast cells are a useful tool for studying normal and abnormal placental development, and unlike cell lines, may be isolated and used to study trophoblast at specific stages of pregnancy. In addition, primary cultures of trophoblast from transgenic mice may be used to study the role of particular genes in placental cells. The protocol presented here is based on the description by Thordarson et al., in which a percoll gradient is used to obtain a relatively pure trophoblast cell population from isolated mouse placentas. It is similar to the more widely used methods for human trophoblast cell isolation. Purity may be assessed by immunocytochemical staining of the isolated cells for cytokeratin 7. Here, the isolated cells are then analyzed using a matrigel invasion assay to assess trophoblast invasiveness in vitro. The invaded cells are analyzed by immunocytochemistry and stained for counting. PMID:22257865

Pennington, Kathleen A; Schlitt, Jessica M; Schulz, Laura C

2012-01-08

155

Mesenchymal stem cells from patients to assay bone graft substitutes.  

PubMed

Bio-engineered scaffolds used in orthopedic clinical applications induce different tissue responses after implantation. In this study, non-stoichiometric Mg(2+) ions and stoichiometric apatites, which are used in orthopedic surgery as bone substitutes, have been assayed in vitro with human adult mesenchymal stem cells (hMSC) to evaluate cytocompatibility and osteoconductivity. hMSCs from the bone marrow aspirates of orthopedic patients were isolated and analyzed by flow cytometry for the surface markers Stro1, CD29, CD44, CD71, CD73, CD90, CD105 (positive) and CD45, CD235 (negative). The hMSC were analyzed for self-renewal capacity and for differentiation potential. The hMSC, which were grown on different biomaterials, were analyzed for (i) cytotoxicity by AlamarBlue metabolic assay, (ii) osteoconductivity by ELISA for activated focal adhesion kinase, (iii) cytoskeleton organization by fluorescence microscopy, and (iv) cell morphology which was investigated by scan electron microscopy (SEM). Results indicate that isolated cell populations agree with minimal criteria for defining hMSC cultures. Non-stoichiometric Mg(2+) and stoichiometric apatites, in granular form, represent a more favorable environment for mesenchymal stem cell adhesion and growth compared to the non-stoichiometric Mg(2+) apatite, in nano-structured paste form. This study indicates that different forms of biomaterials modulate osteoconductivity and cellular growth by differential activation focal adhesion kinase. PMID:23129455

Manfrini, M; Di Bona, C; Canella, A; Lucarelli, E; Pellati, A; D'Agostino, A; Barbanti-Brňdano, G; Tognon, M

2013-06-01

156

Use of reduced temperature cell pausing to enhance flexibility of cell-based assays.  

PubMed

Construction and supply of cell-based reagents for in vitro plate-based screens are often highlighted as a bottleneck within drug discovery. Recent years have seen the successful application of both cryopreservation and automation to increase the capacity and flexibility of cell provision. However, routine cell culture remains a fixed experimental process that requires cells to be prepared and used at specific times. We have investigated the potential of reduced temperature incubation to be used as a simple methodology for stopping and starting cell growth and introduce further flexibility into cell provision. Our results show that incubation of CHOK1, HEK293, and 1321N1 cells at 23 degrees C arrested growth while maintaining cell viability. Recovery of these paused cells at 37 degrees C resulted in resumption of normal cell growth and target protein function. Experiments demonstrated that paused cells, expressing either a recombinant G-protein-coupled receptor or an ion channel, performed comparably with the equivalent continuously cultured cells in a 384-well cell-based assay. This simple technique offers the potential to introduce flexibility into cell culture experiments and processes that were previously considered to be fixed. PMID:19470715

Wise, Helen; Abel, Paul William; Cawkill, Darren

2009-05-21

157

Extended Culture Enhances Sensitivity of a Gamma Interferon Assay for Latent Mycobacterium tuberculosis Infection?  

PubMed Central

To test the hypothesis that prolonged culture would enhance the sensitivity of latent tuberculosis detection by a gamma interferon release assay, blood samples from 33 household contacts of Gambian tuberculosis patients were stimulated with Mycobacterium tuberculosis-specific antigens. After 24 h of culture, 66% were positive, compared to 93% after 6 days of culture.

Cehovin, Ana; Cliff, Jacqueline M.; Hill, Philip C.; Brookes, Roger H.; Dockrell, Hazel M.

2007-01-01

158

A digital microfluidic platform for primary cell culture and analysis.  

PubMed

Digital microfluidics (DMF) is a technology that facilitates electrostatic manipulation of discrete nano- and micro-litre droplets across an array of electrodes, which provides the advantages of single sample addressability, automation, and parallelization. There has been considerable interest in recent years in using DMF for cell culture and analysis, but previous studies have used immortalized cell lines. We report here the first digital microfluidic method for primary cell culture and analysis. A new mode of "upside-down" cell culture was implemented by patterning the top plate of a device using a fluorocarbon liftoff technique. This method was useful for culturing three different primary cell types for up to one week, as well as implementing a fixation, permeabilization, and staining procedure for F-actin and nuclei. A multistep assay for monocyte adhesion to endothelial cells (ECs) was performed to evaluate functionality in DMF-cultured primary cells and to demonstrate co-culture using a DMF platform. Monocytes were observed to adhere in significantly greater numbers to ECs exposed to tumor necrosis factor (TNF)-? than those that were not, confirming that ECs cultured in this format maintain in vivo-like properties. The ability to manipulate, maintain, and assay primary cells demonstrates a useful application for DMF in studies involving precious samples of cells from small animals or human patients. PMID:22094822

Srigunapalan, Suthan; Eydelnant, Irwin A; Simmons, Craig A; Wheeler, Aaron R

2011-11-18

159

Cell-Based Assay For Identifying Peptidase Inhibitors.  

National Technical Information Service (NTIS)

The present invention provides assays for the identification of inhibitors of endopeptidase toxins. The assays utilize genetically engineered yeast cells that contain a conditionally expressed endopeptidase toxin. When conditions for expression of the tox...

H. Fang N. Green

2004-01-01

160

Detection of yeasts in blood cultures by the Luminex xTAG fungal assay.  

PubMed

A multiplex-PCR Luminex xMAP bead probe fluid array using xTAG analyte-specific reagents (multiplex xTAG fungal ASR assay) was employed for detection of clinically significant Candida species, Cryptococcus neoformans, Histoplasma capsulatum, and Blastomyces dermatitidis from blood cultures. We tested 132 blood cultures negative (n = 10) or positive (n = 97) for yeasts and/or bacteria (n = 25). The assay showed sensitivity and specificity of 100% and 99%, respectively. The xTAG fungal ASR assay is a rapid assay that allows simultaneous identification of multiple yeast species. PMID:22170902

Balada-Llasat, Joan-Miquel; LaRue, Heidi; Kamboj, Kamal; Rigali, Lisa; Smith, Debra; Thomas, Keelie; Pancholi, Preeti

2011-12-14

161

Shape Memory Polymers for Active Cell Culture  

PubMed Central

Shape memory polymers (SMPs) are a class of "smart" materials that have the ability to change from a fixed, temporary shape to a pre-determined permanent shape upon the application of a stimulus such as heat1-5. In a typical shape memory cycle, the SMP is first deformed at an elevated temperature that is higher than its transition temperature, Ttrans [either the melting temperature (Tm) or the glass transition temperature (Tg)]. The deformation is elastic in nature and mainly leads to a reduction in conformational entropy of the constituent network chains (following the rubber elasticity theory). The deformed SMP is then cooled to a temperature below its Ttrans while maintaining the external strain or stress constant. During cooling, the material transitions to a more rigid state (semi-crystalline or glassy), which kinetically traps or "freezes" the material in this low-entropy state leading to macroscopic shape fixing. Shape recovery is triggered by continuously heating the material through Ttrans under a stress-free (unconstrained) condition. By allowing the network chains (with regained mobility) to relax to their thermodynamically favored, maximal-entropy state, the material changes from the temporary shape to the permanent shape. Cells are capable of surveying the mechanical properties of their surrounding environment6. The mechanisms through which mechanical interactions between cells and their physical environment control cell behavior are areas of active research. Substrates of defined topography have emerged as powerful tools in the investigation of these mechanisms. Mesoscale, microscale, and nanoscale patterns of substrate topography have been shown to direct cell alignment, cell adhesion, and cell traction forces7-14. These findings have underscored the potential for substrate topography to control and assay the mechanical interactions between cells and their physical environment during cell culture, but the substrates used to date have generally been passive and could not be programmed to change significantly during culture. This physical stasis has limited the potential of topographic substrates to control cells in culture. Here, active cell culture (ACC) SMP substrates are introduced that employ surface shape memory to provide programmed control of substrate topography and deformation. These substrates demonstrate the ability to transition from a temporary grooved topography to a second, nearly flat memorized topography. This change in topography can be used to control cell behavior under standard cell culture conditions.

Davis, Kevin A.; Luo, Xiaofan; Mather, Patrick T.; Henderson, James H.

2011-01-01

162

Shape memory polymers for active cell culture.  

PubMed

Shape memory polymers (SMPs) are a class of "smart" materials that have the ability to change from a fixed, temporary shape to a pre-determined permanent shape upon the application of a stimulus such as heat(1-5). In a typical shape memory cycle, the SMP is first deformed at an elevated temperature that is higher than its transition temperature, T(trans;) [either the melting temperature (T(m;)) or the glass transition temperature (T(g;))]. The deformation is elastic in nature and mainly leads to a reduction in conformational entropy of the constituent network chains (following the rubber elasticity theory). The deformed SMP is then cooled to a temperature below its T(trans;) while maintaining the external strain or stress constant. During cooling, the material transitions to a more rigid state (semi-crystalline or glassy), which kinetically traps or "freezes" the material in this low-entropy state leading to macroscopic shape fixing. Shape recovery is triggered by continuously heating the material through T(trans;) under a stress-free (unconstrained) condition. By allowing the network chains (with regained mobility) to relax to their thermodynamically favored, maximal-entropy state, the material changes from the temporary shape to the permanent shape. Cells are capable of surveying the mechanical properties of their surrounding environment(6). The mechanisms through which mechanical interactions between cells and their physical environment control cell behavior are areas of active research. Substrates of defined topography have emerged as powerful tools in the investigation of these mechanisms. Mesoscale, microscale, and nanoscale patterns of substrate topography have been shown to direct cell alignment, cell adhesion, and cell traction forces(7-14). These findings have underscored the potential for substrate topography to control and assay the mechanical interactions between cells and their physical environment during cell culture, but the substrates used to date have generally been passive and could not be programmed to change significantly during culture. This physical stasis has limited the potential of topographic substrates to control cells in culture. Here, active cell culture (ACC) SMP substrates are introduced that employ surface shape memory to provide programmed control of substrate topography and deformation. These substrates demonstrate the ability to transition from a temporary grooved topography to a second, nearly flat memorized topography. This change in topography can be used to control cell behavior under standard cell culture conditions. PMID:21750496

Davis, Kevin A; Luo, Xiaofan; Mather, Patrick T; Henderson, James H

2011-07-04

163

Principles of cancer cell culture.  

PubMed

The basics of cell culture are now relatively common, though it was not always so. The pioneers of cell culture would envy our simple access to manufactured plastics, media and equipment for such studies. The prerequisites for cell culture are a well lit and suitably ventilated laboratory with a laminar flow hood (Class II), CO(2) incubator, benchtop centrifuge, microscope, plasticware (flasks and plates) and a supply of media with or without serum supplements. Not only can all of this be ordered easily over the internet, but large numbers of well-characterised cell lines are available from libraries maintained to a very high standard allowing the researcher to commence experiments rapidly and economically. Attention to safety and disposal is important, and maintenance of equipment remains essential. This chapter should enable researchers with little prior knowledge to set up a suitable laboratory to do basic cell culture, but there is still no substitute for experience within an existing well-run laboratory. PMID:21516394

Cree, Ian A

2011-01-01

164

Rapid, Specific Detection of Alphaviruses from Tissue Cultures Using a Replicon-Defective Reporter Gene Assay  

PubMed Central

We established a rapid, specific technique for detecting alphaviruses using a replicon-defective reporter gene assay derived from the Sindbis virus XJ-160. The pVaXJ expression vector containing the XJ-160 genome was engineered to form the expression vectors pVaXJ-EGFP expressing enhanced green fluorescence protein (EGFP) or pVaXJ-GLuc expressing Gaussia luciferase (GLuc). The replicon-defective reporter plasmids pVaXJ-EGFP?nsp4 and pVaXJ-GLuc?nsp4 were constructed by deleting 1139 bp in the non-structural protein 4 (nsP4) gene. The deletion in the nsP4 gene prevented the defective replicons from replicating and expressing reporter genes in transfected BHK-21 cells. However, when these transfected cells were infected with an alphavirus, the non-structural proteins expressed by the alphavirus could act on the defective replicons in trans and induce the expression of the reporter genes. The replicon-defective plasmids were used to visualize the presence of alphavirus qualitatively or detect it quantitatively. Specificity tests showed that this assay could detect a variety of alphaviruses from tissue cultures, while other RNA viruses, such as Japanese encephalitis virus and Tahyna virus, gave negative results with this system. Sensitivity tests showed that the limit of detection (LOD) of this replicon-defective assay is between 1 and 10 PFU for Sindbis viruses. These results indicate that, with the help of the replicon-defective alphavirus detection technique, we can specifically, sensitively, and rapidly detect alphaviruses in tissue cultures. The detection technique constructed here may be well suited for use in clinical examination and epidemiological surveillance, as well as for rapid screening of potential viral biological warfare agents.

Wang, Huanqin; Li, Jiandong; Zhang, Quanfu; He, Ying; Li, Jia; Fu, Juanjuan; Li, Dexin; Liang, Guodong

2012-01-01

165

Methods for the Production of Interferon in Cultures of Human Diploid Cells.  

National Technical Information Service (NTIS)

To select a suitable cell culture system for human interferon assays a number of cell types were tested. A plaque-reduction assay, utilizing the U cell line (human amnion) and vesicular stomatitis virus was selected for this work. The diploid human cell s...

J. Vilcek

1971-01-01

166

IRAG Working Group 3: Cell function-based assays  

Microsoft Academic Search

Cell function-based tests measure responses of cells at sublytic concentrations of test agents. The fluorescein leakage assay measures effects of substances on the barrier function of epithelial monolayers or multilayers (MDCK or NHEK cells) as in vitro models of corneal epithelial function. Two IRAG data submissions suggest that the fluorescein leakage assay shows promise as a screening test for surfactants

P. Botham; R. Osborne; K. Atkinson; G. Carr; M. Cottin; R. G. Van Buskirk

1997-01-01

167

Development of a treatment algorithm for streptococci and enterococci from positive blood cultures identified with the verigene gram-positive blood culture assay.  

PubMed

Seventy-eight blood cultures with a Gram stain result of Gram-positive cocci in pairs and/or chains were evaluated with the Nanosphere Verigene Gram-positive blood culture (BC-GP) assay. The overall concordance of the assay with culture was 89.7% (70/78 cultures), allowing for the development of a targeted treatment algorithm. PMID:23985910

Alby, Kevin; Daniels, Lindsay M; Weber, David J; Miller, Melissa B

2013-08-28

168

Neutral red uptake assay for the estimation of cell viability/cytotoxicity.  

PubMed

The neutral red uptake assay provides a quantitative estimation of the number of viable cells in a culture. It is one of the most used cytotoxicity tests with many biomedical and environmental applications. It is based on the ability of viable cells to incorporate and bind the supravital dye neutral red in the lysosomes. Most primary cells and cell lines from diverse origin may be successfully used. Cells are seeded in 96-well tissue culture plates and are treated for the appropriate period. The plates are then incubated for 2 h with a medium containing neutral red. The cells are subsequently washed, the dye is extracted in each well and the absorbance is read using a spectrophotometer. The procedure is cheaper and more sensitive than other cytotoxicity tests (tetrazolium salts, enzyme leakage or protein content). Once the cells have been treated, the assay can be completed in <3 h. PMID:18600217

Repetto, Guillermo; del Peso, Ana; Zurita, Jorge L

2008-01-01

169

An in vitro assay of anterior cruciate ligament (ACL) and medial collateral ligament (MCL) cell migration.  

PubMed

Explants from rabbit anterior cruciate ligaments (ACL) and medial collateral ligaments (MCL) were utilized to compare the relative rates that fibroblasts migrate onto glass and plastic culture surfaces in vitro. During the first two weeks in culture, a monolayer of cells appeared on the periphery of all the ACL and MCL explants. From 45 to 134 hrs in culture, the mean total MCL cell count per explant was 6-12 times greater than that for the ACL on the plastic culture dishes, and this difference was even greater for the cells attached to the glass cover slides over the explants. These differences were significant at the p < .005 level. The rates of cell proliferation were quite similar for primary cultures of ACL and MCL grown in the same medium as that used for the migration assay. The large difference in cell number at early times of culture is thus due to the more rapid MCL cell migration out of the explants, and not to a difference in the rate of cell proliferation. These data support the hypothesis that differences in cell migration rate play a role in the greater healing capacity of the MCL as compared with the ACL. The assay described in this work may then be useful in assessing factors that promote wound healing. PMID:8039388

Geiger, M H; Green, M H; Monosov, A; Akeson, W H; Amiel, D

1994-01-01

170

IRAG Working Group 4: Cell cytotoxicity assays  

Microsoft Academic Search

Twenty-seven data sets from 12 cellular cytotoxicity assays, intended to predict ocular irritation, were submitted to the Interagency Regulatory Alternatives Group (IRAG) for review. These data consisted of paired in vivo (Draize) and in vitro responses to individual chemicals and formulations. In vivo data consisted of individual tissue scores so that the predictive value of the in vitro assay could

J. W. Harbell; S. W. Koontz; R. W. Lewis; D. Lovell; D. Acosta

1997-01-01

171

Adherence of Actinobacillus pleuropneumoniae to primary cultures of porcine lung epithelial cells  

Microsoft Academic Search

To study adherence of Actinobacillus pleuropneumoniae to porcine lower respiratory epithelium, a cell culture model was developed using primary cultures of porcine lung epithelial cells (LEC). Adherence assays were performed and results were compared with data obtained with swine kidney cells (SK6). A. pleuropneumoniae efficiently adhered to LEC with up to 62 bacteria per cell after 2h of incubation. Reference

Bouke K. H. L. Boekema; Norbert Stockhofe-Zurwieden; Hilde E. Smith; Elbarte M. Kamp; Jos P. van Putten; Jos H. Verheijden

2003-01-01

172

Evaluation of bioaerosol sampling techniques for Legionella pneumophila coupled with culture assay and quantitative PCR  

Microsoft Academic Search

Efficient bioaerosol sampling methods are required for characterization of exposure risk to airborne pathogenic Legionella pneumophila, which may cause severe pneumonia and death in humans. By using culture assay and quantitative PCR, the effects of sampler type, sampling time (1–60min), collection fluid (deionized water (DW) and Tween mixture), and DW replenishment during sampling on the recovery of culturable and total

Ching-Wen Chang; Fang-Chen Chou; Pei-Yu Hung

2010-01-01

173

In vitro evaluation of cell/biomaterial interaction by MTT assay.  

PubMed

The tetrazolium-based colorimetric assay (MTT test) measures only in vitro living cells and the results are directly related to the number of viable cultured cells. It has been adopted in immunological investigations, cancer research and, recently, biocompatibility evaluation. We used the MTT method with minor modifications to fit it to an in vitro study of biomaterial-cell interactions. The MTT assay was confirmed to be feasible, rapid and reproducible. Moreover, it showed a good correlation with other in vitro proliferation assays, such as the 3H-thymidine uptake assay. By using the MTT method and the ASTM procedure for extracting biomaterials, we quantified the in vitro cell compatibility of different metals and polymers. PMID:8507779

Ciapetti, G; Cenni, E; Pratelli, L; Pizzoferrato, A

1993-04-01

174

Isolation of organelles from carrot cell suspension cultures  

Microsoft Academic Search

Summary Organelles isolated from carrot cell suspension cultures by density gradient centrifugation and identified by their specific marker enzymes were found at the following mean densities on the sucrose gradient: microbodies 1.25 g\\/cm3 (catalase), mitochondria 1.18 (fumarase), endoplasmic reticulum 1.09 g\\/cm3 (NADH-cytochrome c reductase). Further enzyme assays were done for characterization of microbodies from carrot cultures.

H.-D. Gregor

1977-01-01

175

Circulating Tumor Cell Assay Quality Control and Trouble Shooting Guide  

Cancer.gov

1.1 1.2 Version: July 2010 1.3 Circulating Tumor Cell Assay Quality Control and Trouble Shooting Guide LHTP003.8.1 ?H2AX IMMUNOFLUORESCENCE ASSAY FOR CIRCULATING TUMOR CELLS USING THE CELLSEARCH SYSTEM LHTP003.8.1.1 ?H2AX IMMUNOFLUORESCENCE

176

'Pseudomonas aeruginosa' Exotoxin: Effect on Cell Cultures.  

National Technical Information Service (NTIS)

An exotoxin, toxic to both mice and cultured cells, was isolated from cultures of Pseudomonas aeruginosa. Relatively small amounts of the exotoxin inhibited the uptake of uridine and amino acids by Vero cells. Within limits, this toxic action was reversib...

O. R. Pavlovskis F. B. Gordon

1972-01-01

177

INFLUENCE OF TEMPERATURE ON AN ESTROGEN-RESPONSIVE RAINBOW TROUT CELL TRANSFECTION ASSAY  

EPA Science Inventory

One uncertainty in extrapolating estrogenic effects in mammalian systems to those in fish and wildlife is the influence that temperature has on these effects. A reporter gene assay in cultured rainbow trout cell lines was used to determine the influence of temperature on the exp...

178

Quantitation of Haemopoietic Cells from Normal and Leukaemic RFM Mice Using an In Vivo Colony Assay  

Microsoft Academic Search

The conventional diffusion chamber (CDC) as described by Benestad (1970) had been modified to assay the colony forming capacity of RFM bone marrow and spleen cells in agar diffusion chambers (ADCs). The colonies are morphologically identical to those formed by the CFUc in agar culture in vitro and have an incidence of approximately 1 in 103 normal nucleated bone marrow

M Y Gordon

1974-01-01

179

Use of the tetrazolium assay in measuring the response of human tumor cells to ionizing radiation  

SciTech Connect

Three human tumor cell lines of widely differing radiosensitivity were used to examine the characteristics of the 3-(4,5-dimethyl(thiazol-2-yl)-3,5-diphery)tetradium bromide (MTT) assay and to select suitable conditions for its use in assessing the response of cells to ionizing radiation. The optimal concentration of MTT and the time of incubation of the cells with MTT were individualized for each cell line. The relationship between absorbance and cell number was not linear over the wide range of cell numbers that were used. A calibration curve of absorbance against cell number for each cell line was therefore used. Using the assay to quantify metabolically viable cells, growth curves of irradiated and unirradiated cells were constructed on days 0-14 after irradiation. Accurate surviving fractions could be calculated only when cells were in exponential growth. Using this modification to its interpretation, the MTT assay was able to provide a reproducible measure of survival, which compared well with clonogenic cell survival measurements. However, the necessity to optimize conditions of the MTT assay for each cell line severely limits its usefulness in determining the radiosensitivity of cells in primary human tumor cultures.

Price, P.; McMillan, T.J. (Institute of Cancer Research, Sutton, Surrey (England))

1990-03-01

180

The neurosphere assay applied to neural stem cells and cancer stem cells.  

PubMed

The discovery of neural stem cells (NSCs) in the mammalian brain has raised many expectations as these unique cells might recapitulate different neurological diseases, including brain tumors, both from a functional and molecular perspective. Proper in vitro culturing of NSCs has emerged as a critical methodological issue, given that it should preserve the in vivo features of NSCs, with particular emphasis on cell heterogeneity. At the same time, the methodology for NSC culturing should allow the production of large amounts of cells to be exploited not only for prospective clinical applications, but also for drug screening. Direct in vitro selection of NSCs and, very recently, cancer stem cells (CSCs) by means of defined serum-free conditions represents the most reliable methodology to obtain long-term expanding SC lines. Here we describe the methods currently employed to enrich for NSCs/CSCs based on the NeuroSphere Assay (NSA) and their adaptation to specific assays for testing the efficacy of neuroactive compounds. PMID:23436418

Galli, Rossella

2013-01-01

181

Inhibition of neuronal cell-cell adhesion measured by the microscopic aggregation assay and impedance sensing.  

PubMed

Microscopic aggregation assay and impedance sensing (IS) were used to monitor a change in in vitro neuron-neuron adhesion in response to blocking of cell adhesion molecules. By blocking neuron-neuron adhesion, migration and aggregation of neuronal cells can be inhibited. This leads to better control of spatial arrangement of cells in culture. In the literature N-CAM, L1 and N-cadherin proteins are pointed out as main regulators of neuronal adhesion. In this study, these three main cell adhesion molecules were used to inhibit neuron-to-neuron adhesion and aggregation. Both soluble extracellular domains and antigen antibodies were added to these adhesion molecules. They were investigated for their blocking ability in neuronal cultures. First, in a 96 h aggregation assay on a low-adhesive substrate, the effect of inhibition of the three proteins on aggregation of cortical neurons was investigated optically. Both L1 antibody and L1 protein had no effect on the degree of aggregation. An N-cadherin antibody however was shown to be effective in aggregation inhibition at concentrations of 1 and 3 µg ml(-1). Up to 96 h no aggregation occurred. A similar effect was achieved by the N-cadherin protein, although less distinct. N-CAM blocking revealed no inhibition of aggregation. Second, results from IS corresponded to those of the aggregation assays. In these experiments neuron-neuron adhesion was also inhibited by blocking N-CAM L1 and N-cadherin. Cortical neurons were cultured in small wells containing circular 100 µm diameter gold electrodes, so small changes in cell-cell interactions in monolayers of neurons could be monitored by IS. Impedances of neuron-covered electrodes were significantly lower in the presence of the N-cadherin antibody and protein at concentrations of 1, 3 and 10 µg ml(-1), indicating a less profound binding between adjacent neurons. Results from the aggregation assays and impedance measurements demonstrate the applicability of blocking cell adhesion molecules for inhibition of cell-cell adhesion and aggregation. PMID:20811090

Wiertz, R W F; Marani, E; Rutten, W L C

2010-09-01

182

A microfluidic system for automatic cell culture  

NASA Astrophysics Data System (ADS)

This study presents a new chip capable of automating the cell culture process by using microfluidic technology. This microfluidic cell culture system comprising microheaters, a micro temperature sensor, micropumps, microvalves, microchannels, a cell culture area and several reservoirs was fabricated by using micro-electro-mechanical-systems' fabrication processes. Traditional manual cell culture processes can be performed on this chip. A uni-directional pneumatic micropump was developed to transport the culture reagents and constraint the solutions to flow only in one direction, safeguarding the entire culture process from contamination. A new micro check valve was also used to prevent the culture solutions from flowing back into the microchannels. The microheaters and the micro temperature sensor were used to maintain a constant temperature during the cell culturing process. The pH value suitable for cell growth was also regulated during the cell culture process. A typical cell culturing process for human lung cancer cells (A549) was successfully performed to demonstrate the capability of the developed microfluidic system. This automatic cell culturing system can be eventually integrated with subsequent microfluidic modules for cell purification, collection, counting and lysis to form a cell-based micro-total-analysis system. Preliminary results have been presented in The Asia-Pacific Conference of Transducers and Micro-Nano Technology (APCOT), 25-28 June 2006

Huang, Chun-Wei; Lee, Gwo-Bin

2007-07-01

183

Ultrastructure of cultured cells from Schistosoma japonicum  

Microsoft Academic Search

Ultrastructures and their dynamic changes of the cultured cells from Schistosoma japonicum were observed in the present experiments. Several types—including polygonal, round granular, deltaic fan-shaped and flagellated cells—were found in the cultures. The polygonal cells took a major ratio in the cultures from adult S. japonicum, while the majority from schistosomula was round granular cells. The ultrastuctures on the cell

Hui-Fen Dong; Xiao-Bei Chen; Zhen-Ping Ming; Qin-Ping Zhong; Ming-Sen Jiang

2002-01-01

184

Establishment of primary cell cultures: Experiences with 155 cell strains  

Microsoft Academic Search

Summary Cell culture systems allow the examination of cell populations in a functional state. To simulate in vivo conditions as closely as possible freshly established cell strains are superior to permanent cell lines. Different aspects for the establishment of primary cell cultures obtained from various tissues are compared: (1) Disintegration, (2) culture media supplemented with basal additions, (3) special supplements

M. Dietel; H. Arps; D. Gerding; M. Trapp; A. Niendorf

1987-01-01

185

Single-cell nanotoxicity assays of superparamagnetic iron oxide nanoparticles.  

PubMed

Properly evaluating the nanotoxicity of nanoparticles involves much more than bulk-cell assays of cell death by necrosis. Cells exposed to nanoparticles may undergo repairable oxidative stress and DNA damage or be induced into apoptosis. Exposure to nanoparticles may cause the cells to alter their proliferation or differentiation or their cell-cell signaling with neighboring cells in a tissue. Nanoparticles are usually more toxic to some cell subpopulations than others, and toxicity often varies with cell cycle. All of these facts dictate that any nanotoxicity assay must be at the single-cell level and must try whenever feasible and reasonable to include many of these other factors. Focusing on one type of quantitative measure of nanotoxicity, we describe flow and scanning image cytometry approaches to measuring nanotoxicity at the single-cell level by using a commonly used assay for distinguishing between necrotic and apoptotic causes of cell death by one type of nanoparticle. Flow cytometry is fast and quantitative, provided that the cells can be prepared into a single-cell suspension for analysis. But when cells cannot be put into suspension without altering nanotoxicity results, or if morphology, attachment, and stain location are important, a scanning image cytometry approach must be used. Both methods are described with application to a particular type of nanoparticle, a superparamagnetic iron oxide nanoparticle (SPION), as an example of how these assays may be applied to the more general problem of determining the effects of nanomaterial exposure to living cells. PMID:22975957

Eustaquio, Trisha; Leary, James F

2012-01-01

186

New flow cytometric assays for monitoring cell-mediated cytotoxicity  

PubMed Central

The exact immunologic responses after vaccination that result in effective antitumor immunity have not yet been fully elucidated and the data from ex vivo T-cell assays have not yet defined adequate surrogate markers for clinical efficacy. A more detailed knowledge of the specific immune responses that correlate with positive clinical outcomes should help to develop better or novel strategies to effectively activate the immune system against tumors. Furthermore, clinically relevant material is often limited and, thus, precludes the ability to perform multiple assays. The two main assays currently used to monitor lymphocyte-mediated cytoxicity in cancer patients are the 51Cr-release assay and IFN-? ELISpot assay. The former has a number of disadvantages, including low sensitivity, poor labeling and high spontaneous release of isotope from some tumor target cells. Additional problems with the 51Cr-release assay include difficulty in obtaining autologous tumor targets, and biohazard and disposal problems for the isotope. The ELISpot assays do not directly measure cytotoxic activity and are, therefore, a surrogate marker of cyotoxic capacity of effector T cells. Furthermore, they do not assess cytotoxicity mediated by the production of the TNF family of death ligands by the cytotoxic cells. Therefore, assays that allow for the simultaneous measurement of several parameters may be more advantageous for clinical monitoring. In this respect, multifactor flow cytometry-based assays are a valid addition to the currently available immunologic monitoring assays. Use of these assays will enable detection and enumeration of tumor-specific cytotoxic T lymphocytes and their specific effector functions and any correlations with clinical responses. Comprehensive, multifactor analysis of effector cell responses after vaccination may help to detect factors that determine the success or failure of a vaccine and its immunological potency.

Zaritskaya, Liubov; Shurin, Michael R; Sayers, Thomas J; Malyguine, Anatoli M

2010-01-01

187

New flow cytometric assays for monitoring cell-mediated cytotoxicity.  

PubMed

The exact immunologic responses after vaccination that result in effective antitumor immunity have not yet been fully elucidated and the data from ex vivo T-cell assays have not yet defined adequate surrogate markers for clinical efficacy. A more detailed knowledge of the specific immune responses that correlate with positive clinical outcomes should help to develop better or novel strategies to effectively activate the immune system against tumors. Furthermore, clinically relevant material is often limited and, thus, precludes the ability to perform multiple assays. The two main assays currently used to monitor lymphocyte-mediated cytoxicity in cancer patients are the (51)Cr-release assay and IFN-gamma ELISpot assay. The former has a number of disadvantages, including low sensitivity, poor labeling and high spontaneous release of isotope from some tumor target cells. Additional problems with the (51)Cr-release assay include difficulty in obtaining autologous tumor targets, and biohazard and disposal problems for the isotope. The ELISpot assays do not directly measure cytotoxic activity and are, therefore, a surrogate marker of cyotoxic capacity of effector T cells. Furthermore, they do not assess cytotoxicity mediated by the production of the TNF family of death ligands by the cytotoxic cells. Therefore, assays that allow for the simultaneous measurement of several parameters may be more advantageous for clinical monitoring. In this respect, multifactor flow cytometry-based assays are a valid addition to the currently available immunologic monitoring assays. Use of these assays will enable detection and enumeration of tumor-specific cytotoxic T lymphocytes and their specific effector functions and any correlations with clinical responses. Comprehensive, multifactor analysis of effector cell responses after vaccination may help to detect factors that determine the success or failure of a vaccine and its immunological potency. PMID:20518716

Zaritskaya, Liubov; Shurin, Michael R; Sayers, Thomas J; Malyguine, Anatoli M

2010-06-01

188

Cell?Based Assays Using Primary Endothelial Cells to Study Multiple Steps in Inflammation  

Microsoft Academic Search

Cell?based assays are powerful tools for drug discovery and provide insight into complex signal transduction pathways in higher eukaryotic cells. Information gleaned from assays that monitor a cellular phenotype can be used to elucidate the details of a single pathway and to establish patterns of cross talk between pathways. By selecting the appropriate cell model, cell?based assays can be used

Thomas Mayer; Bernd Jagla; Michael R. Wyler; Peter D. Kelly; Nathalie Aulner; Matthew Beard; Geoffrey Barger; Udo Többen; Deborah H. Smith; Lars Brandén; James E. Rothman

2006-01-01

189

Culture and differentiation of embryonic stem cells  

Microsoft Academic Search

Summary Techniques are described for the culture of murine embryonic stem cells in the absence of heterologous feeder cells and for the induction of differentiation programs. The regulatory factor differentiation inhibiting activity\\/ leukaemia inhibitory factor (DIA\\/LIF) is produced at high concentration by transient expression in Cos cells and is used to suppress stem cell differentiation by addition to the culture

Austin G. Smith

1991-01-01

190

Rapid, sensitive, and validated method for detection of Salmonella in food by an enrichment broth culture – Nested PCR combination assay  

Microsoft Academic Search

A rapid nested PCR assay for detection of Salmonella from food was developed. The sensitivity of the assay developed was comparable to the traditional culture based methods with an advantage in reduction of assay time. The assay procedure with artificially contaminated samples was able to detect as low as 4CFU Salmonella\\/25g of food samples (sprout, carrot, cucumber and poultry meat).

Sunil D. Saroj; R. Shashidhar; Manisha Karani; Jayant R. Bandekar

2008-01-01

191

A novel method for preserving cultured limbal epithelial cells  

PubMed Central

Aim To investigate organ culture preservation of cultured limbal epithelial cells in order to enhance the availability of tissue?engineered epithelia that are used to treat patients with limbal stem cell deficiency. Methods Limbal epithelial cells were cultured for 3?weeks on intact amniotic membrane fastened to a polyester membrane carrier. The cultured epithelia were stored for 1?week at 23°C in organ culture medium. The preserved epithelia were then examined using a colorimetric cell viability assay, light microscopy and immunohistochemistry. Results The viability of the preserved epithelia was 84% (20%), and no statistically significant difference was found compared with non?preserved epithelia. In general, the cell borders were maintained, the nuclei showed no sign of degeneration, and the original layered structure was preserved. Mild intercellular oedema was occasionally observed. Expression of p63, K19 and vimentin was maintained. Conclusions Cultured limbal epithelial cells can be preserved in organ culture medium for 1?week at room temperature, while maintaining the original layered structure and undifferentiated phenotype.

Utheim, Tor Paaske; Raeder, Sten; Utheim, ?ygunn Aass; Cai, Yiqing; Roald, Borghild; Drolsum, Liv; Lyberg, Torstein; Nicolaissen, Bj?rn

2007-01-01

192

Preparation of primary cell cultures from lamprey  

Microsoft Academic Search

The lamprey is an important model for studies of evolution and comparative biology. The ability to culture cells from lamprey tissues makes it possible to employ an in vitro approach to address basic questions in these areas. Methods are described for the initiation of cell cultures derived from tissues of adult and larval sea lamprey (Petromyzon marinus). Primary cultures initiated

Chunguang Ma; Paul Collodi

1999-01-01

193

Radiometric macrophage culture assay for rapid evaluation of antileprosy activity of rifampin  

SciTech Connect

The antileprosy effect of rifampin was evaluated by a newly developed rapid in vitro assay wherein 31 human-derived strains and 1 armadillo-derived strain of Mycobacterium leprae were maintained for 2 and 3 weeks, respectively, in murine and human macrophages in the presence of (3H)thymidine. Of these strains, 27 showed significant incorporation of the radiolabel in cultures of live bacilli as compared with control cultures of heat-killed bacilli of the same strain. Consistent and significant inhibition of (3H)thymidine uptake was observed in M. leprae resident cultures with 3 to 200 ng of rifampin per ml as compared with similar cultures without the drug. In general, an increase in percent inhibition was seen from 3 to 20 ng/ml, with marginal increases at 40, 50, and 100 ng/ml. M. leprae strains appear to be remarkably susceptible to this drug in the in vitro assay.

Mittal, A.; Seshadri, P.S.; Prasad, H.K.; Sathish, M.; Nath, I.

1983-10-01

194

Rotavirus-specific intestinal immune response in mice assessed by enzyme-linked immunospot assay and intestinal fragment culture.  

PubMed Central

Primate rotavirus strain RRV and bovine strain WC3 or reassortants made between these animal viruses and human rotaviruses have been administered to infants as candidate vaccines. We compared RRV and WC3 in a murine model of oral infection. We determined the relative capacities of these viruses to induce a virus-specific humoral immune response by intestinal lymphocytes as tested by enzyme-linked immunospot assay, intestinal fragment culture, and enzyme-linked immunosorbent assay of intestinal contents. We found that inoculation of mice with RRV induced higher frequencies of virus-specific immunoglobulin A (IgA)-secreting cells in the lamina propria, greater quantities of virus-specific IgA in intestinal fragment cultures, and greater quantities of virus-specific IgA in intestinal secretions than did inoculation with WC3 or inactivated RRV (iRRV). The induction of an IgA response in serum was predictive of an IgA response among intestinal lymphocytes after inoculation with RRV but not WC3. In addition, large quantities of IgG, IgA, and IgM not specific for rotavirus were produced in fragment cultures from mice inoculated with RRV but not in cultures from mice inoculated with WC3 or iRRV. Possible mechanisms of RRV-induced polyclonal stimulation of intestinal B cells are discussed.

Khoury, C A; Brown, K A; Kim, J E; Offit, P A

1994-01-01

195

Cell-based resorption assays for bone graft substitutes.  

PubMed

The clinical utilization of resorbable bone substitutes has been growing rapidly during the last decade, creating a rising demand for new resorbable biomaterials. An ideal resorbable bone substitute should not only function as a load-bearing material but also integrate into the local bone remodeling process. This means that these bone substitutes need to undergo controlled resorption and then be replaced by newly formed bone structures. Thus the assessment of resorbability is an important first step in predicting the in vivo clinical function of bone substitute biomaterials. Compared with in vivo assays, cell-based assays are relatively easy, reproducible, inexpensive and do not involve the suffering of animals. Moreover, the discovery of RANKL and M-CSF for osteoclastic differentiation has made the differentiation and cultivation of human osteoclasts possible and, as a result, human cell-based bone substitute resorption assays have been developed. In addition, the evolution of microscopy technology allows advanced analyses of the resorption pits on biomaterials. The aim of the current review is to give a concise update on in vitro cell-based resorption assays for analyzing bone substitute resorption. For this purpose models using different cells from different species are compared. Several popular two-dimensional and three-dimensional optical methods used for resorption assays are described. The limitations and advantages of the current ISO degradation assay in comparison with cell-based assays are discussed. PMID:21971416

Zhang, Ziyang; Egańa, José T; Reckhenrich, Ann K; Schenck, Thilo Ludwig; Lohmeyer, Jörn A; Schantz, Jan Thorsten; Machens, Hans-Günther; Schilling, Arndt F

2011-09-24

196

Phenotypic modulation of swine aortic smooth muscle cells in culture  

SciTech Connect

A study was undertaken to compare aortic smooth muscle cells with log phase cells in terms of DNA and protein synthesis, total protein kinase activity including the relative ratios of amino acid-specific kinases, and phosphoamino acid response of quiescent cells to serum, and nascent proteins and phosphoproteins in the cell layer and conditioned medium. The rate of incorporation of (/sup 3/H)-Tdr in nodular cells was almost negligible when compared to cells 24 hours after seeding while the level of protein synthesis was approximately equal in both cell types. Total protein kinase activity of permeabilized cells was assayed in the presence of 10 mM Ca/sup +2/ or Mn/sup +2/ with exogenous cation omitted in controls. The level of activity measured in Ca/sub 2//sup +/-stimulated assays or in controls did not differ significantly in both cell types. Likewise, the activity of amino acid-specific kinases were also similar. In the Mn/sup +2/-stimulated assay, however, a significant different was observed. The nodular cells had a lower level of activity in this assay that was also reflected in a lower level of phosphotyrosine. When cultures were labeled in vitro with (/sup 32/P)-orthophosphate, incorporation of the label into phosphotyrosine was too low to be measured accurately.

Monical, P.L.

1986-01-01

197

Vesicular release of glutamate from hippocampal neurons in culture: an immunocytochemical assay  

Microsoft Academic Search

Glutamate, the main excitatory neurotransmitter in the brain, may cause excitotoxic damage through excessive release during\\u000a a number of pathological conditions. We have developed an immunocytochemical assay to investigate the mechanisms and regulation\\u000a of glutamate release from intact, cultured neurons. Our results indicate that cultured hippocampal neurons have a large surplus\\u000a of glutamate available for release upon chemically induced depolarization.

Leif Oltedal; Camilla Haglerřd; Tomasz Furmanek; Svend Davanger

2008-01-01

198

A plate reader-compatible microchannel array for cell biology assays.  

PubMed

The use of microfluidic devices for studying cell biology holds considerable promise when compared to canonical culture systems. However, the lack of compatibility with existing infrastructure hinders the application of microfluidic devices in the life sciences. Here, we present a microchannel cell culture platform having both operational (compatible with plate readers and pipetting) and performance (lower detection limits, controlled microenvironment) advantages. We demonstrated rapid growth assays and immunocytochemistry on mammary epithelial cells (both a cell line and primary cells) in the microchannel arrays. The utilization of ubiquitous pipetting methods and plate reader endpoints lowers the barriers to use. The simplicity and flexibility of the platform, combined with the throughput of automated detection systems, will facilitate the adoption of microfluidic culture systems in biological laboratories. PMID:17330172

Yu, Hongmei; Alexander, Caroline M; Beebe, David J

2007-01-02

199

Cell-based antioxidant protection assay  

US Patent & Trademark Office Database

Methods are provided herein for determining antioxidant activity of a test sample in intact cells. The method includes determining the antioxidant capacity of a test sample in intact red blood cells, wherein the test sample is added to intact red blood cells and oxidative damage is measured by alteration of fluorescence intensity of an oxidation-sensitive fluorescent indicator dye.

2013-06-18

200

Proliferative assays for B cell function.  

PubMed

This unit describes procedures for measuring the capacity of purified B cells to undergo proliferation. The method centers on the use of polyclonal stimulating agents (mitogens) because these agents stimulate the majority of B cells and because the alternative (measurement of antigen-induced proliferation) requires the laborious procedures of isolating antigen-specific B cells (which are otherwise present in too low a concentration in whole B cell populations). Cross-linking of the B cell antigen receptor, surface immunoglobulin (sIg), by specific antigen stimulates cells to proliferate prior to secreting Ig. For this purpose, monoclonal or heterologous affinity-purified anti-Ig antibodies are used. B cells can also be stimulated to proliferate by antigen-nonspecific reagents (mitogens), and it is also critical to study the role of these mitogens in B cell responses. Both of these systems have the advantage that the majority of B cells will be activated. The first basic protocol describes B cell proliferation induced by two commonly used stimulants--anti-Ig antibody (either anti-IgM or anti-IgD) and lipopolysaccharide (LPS)--as measured by incorporation of [3H]thymidine into dividing cells. Alternate protocols describe other commonly used mitogens as well as other means of measuring cell proliferation. PMID:18432906

Mond, James J; Brunswick, Mark

2003-11-01

201

Improved detection of cell surface proteins using an electrochemiluminescent cell-binding assay.  

PubMed

Cell surface protein profiling is a generic tool to determine the quality of cultured mammalian cell lines. Flow cytometry is commonly employed as the screening technique of choice, but it consumes a large quantity of cells. We have evaluated an electrochemiluminescent (ECL)-based platform, the Meso Scale Discovery (MSD) Sector 6000 Imager, for cell surface protein detection with fewer than 100 cells per well. The detection of CD13 on human foreskin fibroblast (HFF) cells was evaluated using indirect detection of the reverse-phase immunoassays in 96-well and 384-well plate formats. The study has shown robust cell surface detection of CD13 on HFF cells using the 384-well plate format, with a LOD of 15.3 ± 6.5 cells (n=3). The 96-well plate format exhibited far greater variability between experiments, such that the best LOD obtained was 42.5 cells per well. We have demonstrated, with our model system, the feasibility to perform cell-binding assays with as few as 15 cells per well of a 384-well microplate using the MSD platform. PMID:20688072

Pang, Susan; Ahsan, Enamul S; Foy, Carole A

2010-08-03

202

Comet assay, cloning assay, and light and electron microscopy on one preselected cell  

NASA Astrophysics Data System (ADS)

In order to perform long-term studies up to one week on a preselected single cell after micromanipulation (e.g. UVA and NIR microbeam exposure) in comparison with non-treated neighbor cells (control cells) we applied a variety of single cell diagnostic techniques and developed a special comet assay for single preselected cells. For that purpose adherent cells were grown in low concentrations and maintained in special sterile centimeter-sized glass cell chambers. After preselection, a single cell was marked by means of diamond-produced circles on the outer cell chamber window. During exposure to microbeams, NADH-attributed autofluorescence of the chosen cell was detected by fluorescence imaging and spectroscopy. In addition, cell morphology was video-monitored (formation of pseudopodia, membrane blebbing,...). Maintaining the microchamber in the incubator, the irradiated cell was examined 24 h later for cell division (clone formation) and modifications in autofluorescence and morphology (including daughter cells). In the case that no division occurred the vitality of the light-exposed cell and of the control cells were probed by intranuclear propidium iodide accumulation. After fixation, either electron microscopy or single cell gel electrophoresis (comet assay) was performed. To monitor comet formation indicating photoinduced DNA damage in the preselected single cell in comparison with the non-exposed neighbor cells the chamber was filled with low-melting gel and lysis solution and exposed to an electric field. In contrast to the conventional comet assay, where only randomly chosen cells of a suspension are investigated, the novel optimized electrophoresis technique should enhance the possibilities of DNA damage detection to a true single (preselected) cell level. The single cell techniques applied to UVA microexposed Chinese hamster ovary cells (364 nm, 1 mW, 3.5 W/cm2) revealed significant cell damage for J/cm2 fluences such as modifications of intracellular redox state, impaired cell division, formation of giant cells and cell shrinking, swelling of mitochondria and loss of cristae as well as DNA damage.

Koenig, Karsten; Oehring, H.; Halbhuber, Karl-Juergen; Fiedler, Ursula; Bauer, Eckhard; Greulich, Karl O.

1997-12-01

203

The effect of sodium hypochlorite and chlorhexidine on cultured human periodontal ligament cells  

Microsoft Academic Search

Objective: The objective of this study was to examine the effects of sodium hypochlorite (NaOCl) and chlorhexidine (CHx) on cultured human periodontal ligament (PDL) cells in vitro. Study Design: The effects of irrigation solutions on human PDL cells were evaluated by propidium iodide fluorescence cytotoxicity assay, protein synthesis assay, and mitochondrial activity. Results: Both NaOCl and CHx were cytotoxic to

Yu-Chao Chang; Fu-Mei Huang; Kuo-Wei Tai; Ming-Yung Chou

2001-01-01

204

Cigarette Smoke Toxicants Alter Growth and Survival of Cultured Mammalian Cells  

Microsoft Academic Search

Our purpose was to determine the effects of six cigarette toxicants (pyridine, nicotine, 2-ethylpyridine, 3-ethylpyridine, p- cresol, and pyrazine) on three types of cultured mammalian cells (human umbilical vein endothelial cells (HUVECs), human microvascular endothelial cells (HMVECs), and NIH 3T3 cells) using a cell proliferation\\/survival assay. Synchronized cells were cultured in proliferation or survival medium containing various doses (10? 18M-10?

Richard Yu; M. Wu; S. Lin; Prue Talbot

2006-01-01

205

A highly sensitive, non-radioactive assay for T cell activation in cattle: applications in screening for antigens recognised by CD4 + and CD8 + T cells  

Microsoft Academic Search

We describe a highly sensitive, non-radioactive assay for T cell activation, based on the rapid induction of class II MHC expression by constitutively negative bovine endothelial cells, when cultured in the presence of supernatants derived from activated bovine T cells. We demonstrate the effectiveness of this assay in detecting rBoIFN? and activation of immune CD4+ and CD8+ T cell lines

Keith T. Ballingall; Duncan M. Mwangi; Niall D. MacHugh; Evans L. N. Taracha; Philippe Totte; Declan J. McKeever

2000-01-01

206

Coupled-enzyme and direct assays for uroporphyrinogen III synthase activity in human erythrocytes and cultured lymphoblasts. Enzymatic diagnosis of heterozygotes and homozygotes with congenital erythropoietic porphyria.  

PubMed

Rapid and reproducible assays for uroporphyrinogen III synthase (URO-S; EC 4.2.1.75) have been developed and used to determine the enzymatic activity in human erythrocytes and cultured lymphoid cells. In the coupled-enzyme assay, porphobilinogen was first converted to hydroxymethylbilane, the natural substrate for URO-S, by hydroxymethylbilane synthase which was conveniently obtained from heat-treated erythrocyte lysates. In the direct assay, synthetic hydroxymethylbilane was used as substrate. In both assays, the uroporphyrinogen reaction products were oxidized to their respective uroporphyrin isomers, which were then resolved and quantitated by reversed-phase high-pressure liquid chromatography. Both assays were optimized for pH, substrate concentration, and linearity with time and protein concentration. The mean URO-S activities in normal human erythrocyte lysates determined by the coupled-enzyme and direct assays were 7.41 +/- 1.35 and 7.64 +/- 1.73 units/mg protein, respectively. In normal human cultured lymphoid cells, the mean activities were 13.7 +/- 1.39 and 17.6 +/- 1.15 units/mg protein for the coupled-enzyme and direct assays, respectively. In four families with congenital erythropoietic porphyria, both assays reliably identified the markedly decreased URO-S activities in erythrocytes and cultured lymphoid cells from affected homozygotes and the half-normal activities in these sources from obligate heterozygotes. The coupled-enzyme assay was easier to perform and was suited for clinical diagnostic assays and for monitoring enzyme purification procedures, while the direct assay, which required substrate preparation and technical dexterity, was best for kinetic studies of URO-S. PMID:3674403

Tsai, S F; Bishop, D F; Desnick, R J

1987-10-01

207

DETECTION OF ANEUPLOIDY BY A MONOCHROMOSOMAL HYBRID CELL ASSAY  

EPA Science Inventory

A short-term assay utilizing human/mouse monochromosomal hybrid cells to detect chemically-induced aneuploidy in mammalian cells is described. A single human chromosome transferred into mouse cells was used as a cytogenetic marker to quantitate abnormal chromosome segregation fol...

208

Comparison of Culture and a Novel 5? Taq Nuclease Assay for Direct Detection of Campylobacter fetus subsp. venerealis in Clinical Specimens from Cattle  

PubMed Central

A Campylobacter fetus subsp. venerealis-specific 5? Taq nuclease PCR assay using a 3? minor groove binder-DNA probe (TaqMan MGB) was developed based on a subspecies-specific fragment of unknown identity (S. Hum, K. Quinn, J. Brunner, and S. L. On, Aust. Vet. J. 75:827-831, 1997). The assay specifically detected four C. fetus subsp. venerealis strains with no observed cross-reaction with C. fetus subsp. fetus-related Campylobacter species or other bovine venereal microflora. The 5? Taq nuclease assay detected approximately one single cell compared to 100 and 10 cells in the conventional PCR assay and 2,500 and 25,000 cells from selective culture from inoculated smegma and mucus, respectively. The respective detection limits following the enrichments from smegma and mucus were 5,000 and 50 cells/inoculum for the conventional PCR compared to 500 and 50 cells/inoculum for the 5? Taq nuclease assay. Field sampling confirmed the sensitivity and the specificity of the 5? Taq nuclease assay by detecting an additional 40 bulls that were not detected by culture. Urine-inoculated samples demonstrated comparable detection of C. fetus subsp. venerealis by both culture and the 5? Taq nuclease assay; however, urine was found to be less effective than smegma for bull sampling. Three infected bulls were tested repetitively to compare sampling tools, and the bull rasper proved to be the most suitable, as evidenced by the improved ease of specimen collection and the consistent detection of higher levels of C. fetus subsp. venerealis. The 5? Taq nuclease assay demonstrates a statistically significant association with culture (?2 = 29.8; P < 0.001) and significant improvements for the detection of C. fetus subsp. venerealis-infected animals from crude clinical extracts following prolonged transport.

McMillen, Lyle; Fordyce, Geoffry; Doogan, Vivienne J.; Lew, Ala E.

2006-01-01

209

Cell fusion assays for yeast mating pairs.  

PubMed

Yeast mating provides an accessible genetic system for the discovery of fundamental mechanisms in eukaryotic cell fusion. Although aspects of yeast mating related to pheromone signaling and polarized growth have been intensively investigated, fusion itself is poorly understood. This chapter describes methods for measuring the overall efficiency of yeast cell fusion and for monitoring various stages of the fusion process including cell wall remodeling, plasma membrane fusion, and nuclear fusion. PMID:18979244

Grote, Eric

2008-01-01

210

Electrical wound-healing assay for cells in vitro  

Microsoft Academic Search

Confluent cell monolayers in tissue culture are fragile and can easily be mechanically disrupted, often leaving an area devoid of cells. This opening in the cell sheet is then repopulated, because the cells on the fringe of the damage, which are no longer contact-inhibited, move into the available space. This mechanical disruption is often done deliberately in a \\

Charles R. Keese; Joachim Wegener; Sarah R. Walker; Ivar Giaever

2004-01-01

211

A Simple High-Content Cell Cycle Assay Reveals Frequent Discrepancies between Cell Number and ATP and MTS Proliferation Assays  

PubMed Central

In order to efficiently characterize both antiproliferative potency and mechanism of action of small molecules targeting the cell cycle, we developed a high-throughput image-based assay to determine cell number and cell cycle phase distribution. Using this we profiled the effects of experimental and approved anti-cancer agents with a range mechanisms of action on a set of cell lines, comparing direct cell counting versus two metabolism-based cell viability/proliferation assay formats, ATP-dependent bioluminescence, MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) reduction, and a whole-well DNA-binding dye fluorescence assay. We show that, depending on compound mechanisms of action, the metabolism-based proxy assays are frequently prone to 1) significant underestimation of compound potency and efficacy, and 2) non-monotonic dose-response curves due to concentration-dependent phenotypic ‘switching’. In particular, potency and efficacy of DNA synthesis-targeting agents such as gemcitabine and etoposide could be profoundly underestimated by ATP and MTS-reduction assays. In the same image-based assay we showed that drug-induced increases in ATP content were associated with increased cell size and proportionate increases in mitochondrial content and respiratory flux concomitant with cell cycle arrest. Therefore, differences in compound mechanism of action and cell line-specific responses can yield significantly misleading results when using ATP or tetrazolium-reduction assays as a proxy for cell number when screening compounds for antiproliferative activity or profiling panels of cell lines for drug sensitivity.

Chan, Grace Ka Yan; Kleinheinz, Tracy L.; Peterson, David; Moffat, John G.

2013-01-01

212

The further development of rainbow trout primary epithelial cell cultures as a diagnostic tool in ecotoxicology risk assessment  

Microsoft Academic Search

The use of short-term cytotoxicity assays for the initial screening of chemicals not only aids in establishing priorities for the selection of chemicals that should be tested in vivo, but also decreases the time in which potential toxicants can be valued. Rainbow trout primary skin epithelial cell cultures are one such assay. Rainbow trout primary skin cell cultures contain two

Kevin Dowling; Carmel Mothersill

2001-01-01

213

Design and interpretation of cell trajectory assays.  

PubMed

Cell trajectory data are often reported in the experimental cell biology literature to distinguish between different types of cell migration. Unfortunately, there is no accepted protocol for designing or interpreting such experiments and this makes it difficult to quantitatively compare different published datasets and to understand how changes in experimental design influence our ability to interpret different experiments. Here, we use an individual-based mathematical model to simulate the key features of a cell trajectory experiment. This shows that our ability to correctly interpret trajectory data is extremely sensitive to the geometry and timing of the experiment, the degree of motility bias and the number of experimental replicates. We show that cell trajectory experiments produce data that are most reliable when the experiment is performed in a quasi-one-dimensional geometry with a large number of identically prepared experiments conducted over a relatively short time-interval rather than a few trajectories recorded over particularly long time-intervals. PMID:23985736

Bowden, Lucie G; Simpson, Matthew J; Baker, Ruth E

2013-08-28

214

Cell Culture as an Alternative in Education.  

ERIC Educational Resources Information Center

|Programs that are intended to inform and provide "hands-on" experience for students and to facilitate the introduction of cell culture-based laboratory exercises into the high school and college laboratory are examined. The components of the CellServ Program and the Cell Culture Toxicology Training Programs are described. (KR)|

Nardone, Roland M.

1990-01-01

215

Comparison of whole blood and PBMC assays for T-cell functional analysis  

PubMed Central

Background Tuberculosis remains the foremost cause of morbidity and mortality, more than any other single infectious disease in the world. Cell mediated immune response plays a crucial role in the control of tuberculosis. Therefore, measuring cell mediated immune response against the antigens is having a vital role in understanding the pathogenesis of tuberculosis, which will also help in the diagnosis of and vaccination for tuberculosis. Findings The aim of the present study was to compare and optimize the assay conditions to measure the cell mediated immune response against M. tuberculosis specific antigens. Because the conventional PBMC assays (due to requirement of large volume of blood sample) are unable to screen more number of antigens within the same blood sample. So, here we have compared 6 days culture supernatants of 1:5 and 1:10 diluted blood and PBMCs from healthy laboratory volunteers, to assess the proliferative response of T lymphocytes and secreted IFN-? levels against purified recombinant antigen of M. tuberculosis (MPT51, Rv3803c), crude antigens of M. tuberculosis (PPD) and mitogen (PHA). Conclusions We have observed good correlation between each assay and also the mean difference of these assays did not reach the statistical significance (p?>?0.05). From these results, we conclude that 1:10 diluted whole-blood cultures can be well-suited as an alternative assay to measure cytokine production and lymphocyte proliferation in comparison to the conventional PBMC assays. Moreover, 1:10 diluted blood assays require less volume of blood when compared to PBMC assays which will be useful particularly in paediatric and field studies in endemic countries, where blood volume is a limiting factor.

2013-01-01

216

Expression of recombinant calf prochymosin in mammalian cell culture.  

PubMed

The calf preprochymosin cDNA was cloned into an extrachromosomal mammalian cell expression vector containing Epstein-Barr virus sequences using polymerase chain reaction. Transfection of HeLa cells yielded Hygromycin B resistant cell clones, expressing immunoreactive prochymosin, which was quantitatively secreted into the culture medium. Based on Western blotting we estimated that selected cell clones produced about 10-20 mg prochymosin per liter in 20 h. The biological activity of the secreted chymosin was confirmed by milk clotting assay. PMID:1369334

Kolmer, M; Ord, T; Ulmanen, I

1991-09-01

217

Genotoxic effects of oestrogens in breast cells detected by the micronucleus assay and the Comet assay  

Microsoft Academic Search

Cumulative exposure to oestrogen has been linked to increased risk of breast cancer. Whilst oestrogens induce cancers in rodent bioassays it is unclear whether the mechanisms involved are genotoxic and\\/or epigenetic. The cytokinesis block micronucleus (CBMN) and the alkaline single cell-gel electrophoresis 'Comet' assays were used to examine MCF-7 cells for chromosomal damage and DNA single-strand breaks (SSBs), respectively. The

Edom Yared; Trevor J. McMillan; Francis L. Martin

2002-01-01

218

Angiotensinogen Secretion by Single Rat Pituitary Cells: Detection by a Reverse Haemolytic Plaque Assay and Cell Identification by Immunocytochemistry  

Microsoft Academic Search

sA reverse haemolytic plaque assay (RHPA) for angiotensinogen was developed in rat hepatoma H4 cells and applied to investigate the possible secretion of angiotensinogen from rat pituitary cells in primary culture. Over a 24-hour incubation period in Cunningham chambers plaques with a mean area of 2,800 ± 430 and 590 ± 220 ?mV plaque (SD, n = 6) formed around

Conrad Sernia; Trixie A. Shinkel; Walter G. Thomas; Ken K. Y. Ho; David Lincoln

1992-01-01

219

Quantitative cell-adhesion assay for Clostridium difficile cytotoxin  

Microsoft Academic Search

Summary. A quantitative assay for Clostridium dzficile cytotoxin has been developed, based on the observation that suspended fibroblasts exposed to cytotoxin fail to adhere to plastic. A dye-binding technique was used to quantitate adherent cells, in order to obviate microscopy. Adherent BHK cells were fixed with glutaraldehyde and cell protein was stained with Coomassie blue R-250. Cell-bound dye was eluted

B. C. Mayall; CAROLINE EDMONDS; G. E. GRlFFlNt

1987-01-01

220

Cytotoxicity of Voriconazole on Cultured Human Corneal Endothelial Cells?  

PubMed Central

The purpose of the present study was to evaluate the toxicity of voriconazole on cultured human corneal endothelial cells (HCECs). HCECs were cultured and exposed to various concentrations of voriconazole (5.0 to 1,000 ?g/ml). Cell viability was measured using a Cell Counting Kit-8 (CCK-8) and live/dead viability/cytotoxicity assays. Cell damage was assessed using phase-contrast microscopy after 24 h of exposure to voriconazole. To analyze the effect of voriconazole on the intercellular barrier, immunolocalization of zonula occludens 1 (ZO1) was performed. A flow cytometric assay was performed to evaluate the apoptotic and necrotic effects of voriconazole on HCECs. Cytotoxicity tests demonstrated the dose-dependent toxic effect of voriconazole on HCECs. Voriconazole concentrations of ?100 ?g/ml led to a significant reduction in cell viability. The morphological characteristics of HCECs also changed in a dose-dependent manner. Increasing concentrations of voriconazole resulted in fading staining for ZO1. Higher concentrations of voriconazole resulted in an increased number of propidium iodide (PI)-positive cells, indicating activation of the proapoptotic pathway. In conclusion, voriconazole may have a dose-dependent toxic effect on cultured HCECs. The results of this study suggest that although voriconazole concentrations of up to 50 ?g/ml do not decrease cell viability, intracameral voriconazole concentrations of ?100 ?g/ml may increase the risk of corneal endothelial damage.

Han, Sang Beom; Shin, Young Joo; Hyon, Joon Young; Wee, Won Ryang

2011-01-01

221

An in vitro clonogenic assay to assess radiation damage in rat CNS glial progenitor cells.  

PubMed

Normal glial progenitor cells can be isolated from the rat central nervous system (CNS) and cultured in vitro on a monolayer of type-1 astrocytes. These monolayers are able to support and stimulate explanted glial progenitor cells to proliferate. Employing these in vitro interactions of specific glial cell types, an in vivo-in vitro clonogenic assay has been developed. This method offers the possibility to study the intrinsic radiosensitivity, repair and regeneration of glial progenitor cells after in vitro or in vivo irradiation. PMID:1977827

van der Maazen, R W; Verhagen, I; van der Kogel, A J

1990-11-01

222

Esophageal stem cells and 3D-cell culture models.  

PubMed

The following on esophageal stem cells and 3D-cell culture models contains commentaries on metaplasia through transdifferentiation and through stem cells; transcription factors that may determine an intestinal-like phenotype; the?in vitro, organotypic cell culture models; and the role of stem cells in Barrett's esophagus and its dysplastic progression. PMID:21950821

Souza, Rhonda F; Schwartz, Robert E; Mashimo, Hiroshi

2011-09-01

223

Normal and leukemic human stem cells assayed in SCID mice  

Microsoft Academic Search

Understanding the processes that regulate the developmental program of normal stem cells and those that initiate proliferative diseases such as leukemia remains one of the major challenges in biology. Progress to address these major questions in the human hematopoietic system have been hampered, until recently, by the lack of in-vivo assays for normal and leukemic stem cells. The recent development

John E. Dick

1996-01-01

224

Automated platform for sensor-based monitoring and controlled assays of living cells and tissues.  

PubMed

Cellular assays have become a fundamental technique in scientific research, pharmaceutical drug screening or toxicity testing. Therefore, the requirements of technical developments for automated assays raised in the same rate. A novel measuring platform was developed, which combines automated assay processing with label-free high-content measuring and real-time monitoring of multiple metabolic and morphologic parameters of living cells or tissues. Core of the system is a test plate with 24 cell culture wells, each equipped with opto-chemical sensor-spots for the determination of cellular oxygen consumption and extracellular acidification, next to electrode-structures for electrical impedance sensing. An automated microscope provides the optical sensor read-out and allows continuous cell imaging. Media and drugs are supplied by a pipetting robot system. Therefore, assay can run over several days without personnel interaction. To demonstrate the performance of the platform in physiologic assays, we continuously recorded the kinetics of metabolic and morphologic parameters of MCF-7 breast cancer cells under the influence of the cytotoxin chloroacetaldehyde. The data point out the time resolved effect kinetics over the complete treatment period. Thereby, the measuring platform overcomes problems of endpoint tests, which cannot monitor the kinetics of different parameters of the same cell population over longer time periods. PMID:23838277

Wolf, P; Brischwein, M; Kleinhans, R; Demmel, F; Schwarzenberger, T; Pfister, C; Wolf, B

2013-06-25

225

Label-free cell-based assays using photonic crystal optical biosensors.  

PubMed

Biosensor technologies that have been primarily used in the past for characterizing biomolecular interactions are now being used to develop new approaches for performing cell-based assays. Biosensors monitor cell attachment to a transducer surface, and thus provide information that is fundamentally different from that provided by microscopy, as the sensor is capable of monitoring temporal evolution of integrin-surface interactions that are difficult to measure by other means. Label-free biosensor technologies are especially advantageous for monitoring the behavior of cells because they do not require stains that typically result in cell death, and are not subject to effects such as photobleaching. As a result, cells can be quantitatively monitored in their culture environment over an extended period of time while processes such as proliferation, apoptosis, cytotoxicity, chemotaxis, ion channel activation, and membrane-bound protein activation are modulated by the introduction of a variety of chemical or biological stimuli. This review describes the application of photonic crystal optical biosensor microplates to a variety of cell-based assays. Detection instruments for photonic crystals measure the aggregate behavior of large cell populations, or, using recently developed biosensor imaging detection, independent monitoring of individual cells. These technological developments offer the ability to perform assays with a limited number of available cells for applications such as high throughput screening with primary cells or stem cells. PMID:21279202

Shamah, Steven M; Cunningham, Brian T

2011-01-28

226

Oscillatory behavior of cells in tissue culture  

Microsoft Academic Search

Fibroblasts and epithelial cells organize themselves in distinct patterns in tissue culture which indicates that neighboring cells communicate. A striking example of such communication is the oscillatory behavior of Madin-Darby canine kidney (MDCK) cells reported here. These oscillations were discovered using a biosensor referred to as ECIS (Electric Cell-substrate Impedance Sensing). In this measurement cells are seeded out on a

Ivar Giaever; Michael F. A. Linton; Charles R. Keese

1998-01-01

227

Culture of Cells from Amphibian Embryos.  

ERIC Educational Resources Information Center

|Describes a method for in vitro culturing of cells from amphibian early embryos. Such cells can be used to demonstrate such properties of eukaryote cells as cell motility, adhesion, differentiation, and cell sorting into tissues. The technique may be extended to investigate other factors. (Author/JN)|

Stanisstreet, Martin

1983-01-01

228

Cocoa bean cell and embryo culture  

Microsoft Academic Search

Callus culture of cocoa bean was initiated from immature cotyledons on agar medium. By dispersing these callus cells, a liquid\\u000a suspension culture was established. The lipid composition of cocoa suspension culture was investigated and compared with those\\u000a of cocoa beans of different maturities. Factors affecting fatty acid and triglyceride synthesis in cocoa suspension cultures\\u000a also were studied. In parallel studies,

Ming-Che Wen; Bruce German; John E. Kinsella

1984-01-01

229

Real time assays for quantifying cytotoxicity with single cell resolution.  

PubMed

A new live cell-based assay platform has been developed for the determination of complement dependent cytotoxicity (CDC), antibody dependent cellular cytotoxicity (ADCC), and overall cytotoxicity in human whole blood. In these assays, the targeted tumor cell populations are first labeled with fluorescent Cell Tracker dyes and immobilized using a DNA-based adhesion technique. This allows the facile generation of live cell arrays that are arranged arbitrarily or in ordered rectilinear patterns. Following the addition of antibodies in combination with serum, PBMCs, or whole blood, cell death within the targeted population can be assessed by the addition of propidium iodide (PI) as a viability probe. The array is then analyzed with an automated microscopic imager. The extent of cytotoxicity can be quantified accurately by comparing the number of surviving target cells to the number of dead cells labeled with both Cell Tracker and PI. Excellent batch-to-batch reproducibility has been achieved using this method. In addition to allowing cytotoxicity analysis to be conducted in real time on a single cell basis, this new assay overcomes the need for hazardous radiochemicals. Fluorescently-labeled antibodies can be used to identify individual cells that bear the targeted receptors, but yet resist the CDC and ADCC mechanisms. This new approach also allows the use of whole blood in cytotoxicity assays, providing an assessment of antibody efficacy in a highly relevant biological mixture. Given the rapid development of new antibody-based therapeutic agents, this convenient assay platform is well-poised to streamline the drug discovery process significantly. PMID:23826123

Hsiao, Sonny C; Liu, Hong; Holstlaw, Taylor A; Liu, Cheng; Francis, Catherine Y; Francis, Matthew B

2013-06-24

230

A Duplex PCR-Based Assay for Measuring the Amount of Bacterial Contamination in a Nucleic Acid Extract from a Culture of Free-Living Protists  

PubMed Central

Background Cultures of heterotrophic protists often require co-culturing with bacteria to act as a source of nutrition. Such cultures will contain varying levels of intrinsic bacterial contamination that can interfere with molecular research and cause problems with the collection of sufficient material for sequencing. Measuring the levels of bacterial contamination for the purposes of molecular biology research is non-trivial, and can be complicated by the presence of a diverse bacterial flora, or by differences in the relative nucleic acid yield per bacterial or eukaryotic cell. Principal Findings Here we describe a duplex PCR-based assay that can be used to measure the levels of contamination from marine bacteria in a culture of loricate choanoflagellates. By comparison to a standard culture of known target sequence content, the assay can be used to quantify the relative proportions of bacterial and choanoflagellate material in DNA or RNA samples extracted from a culture. We apply the assay to compare methods of purifying choanoflagellate cultures prior to DNA extraction, to determine their effectiveness in reducing bacterial contamination. Together with measurements of the total nucleic acid concentration, the assay can then be used as the basis for determining the absolute amounts of choanoflagellate DNA or RNA present in a sample. Conclusions The assay protocol we describe here is a simple and relatively inexpensive method of measuring contamination levels in nucleic acid samples. This provides a new way to establish quantification and purification protocols for molecular biology and genomics in novel heterotrophic protist species. Guidelines are provided to develop a similar protocol for use with any protistan culture. This assay method is recommended where qPCR equipment is unavailable, where qPCR is not viable because of the nature of the bacterial contamination or starting material, or where prior sequence information is insufficient to develop qPCR protocols.

Marron, Alan O.; Akam, Michael; Walker, Giselle

2013-01-01

231

Lactate Transport in Cultured Glial Cells  

Microsoft Academic Search

Uptake of L-lactate was investigated with a radioactive tracer method in cultured rat glioma cells and in astroglia-rich primary cultures derived from rat brain. In the glioma cells, a saturable component of uptake was identified with half-maximal uptake occurring at 1.0±0.4 mM lactate. In addition, a non-saturable component dominated the uptake at high concentrations of lactate. In astroglia-rich primary cultures,

Ralf Dringen; Hajo Peters; Heinrich Wiesinger; Bernd Hamprecht

1995-01-01

232

Effect of high polyol concentrations on the neutral red absorption assay and tetrazolium-MTT test of rat hepatocytes in primary culture  

Microsoft Academic Search

The effects of three polyols, mannitol, sorbitol and xylitol, on primary cultures of rat hepatocytes were studied with the aid of two cytotoxicity markers, the MTT test and the neutral red assay. A dose-related increase in the uptake of neutral red (up to approximately 60%) was observed in comparison with untreated cells, whereas the MTT test was unaffected by concentrations

P. Olivier; P. Testard; D. Marzin; D. Abbott

1995-01-01

233

Glucosylation of taxifolin with cultured plant cells.  

PubMed

Cultured plant cells of Eucalyptus perriniana glucosylated taxifolin to its 3'- and 7-O-beta-D-glucosides and 3',7-O-beta-D-diglucoside. On the other hand, taxifolin was converted into 3'- and 7-O-beta-D-glucosides by cultured cells of Nicotiana tabacum and Catharanthus roseus. PMID:23980419

Shimoda, Kei; Kubota, Naoji; Hamada, Manabu; Sugamoto, Masahiro; Ishihara, Kohji; Hamada, Hatsuyuki; Hamada, Hiroki

2013-07-01

234

Crustacean primary cell culture: A technical approach  

Microsoft Academic Search

Crustacean cell culture has gained attention as a potent model to assist in the development of diagnostic reagents and probes for use in the shrimp, crayfish and lobster industries. The availability of such cellular tools is especially important to industries which use intensive aquaculture methods and thus have increased risk of disease problems. Indeed, crustacean cell cultures offer potential for

Jean-Yves Toullec

1999-01-01

235

A Microwell Cell Culture Platform for the Aggregation of Pancreatic ?-Cells  

PubMed Central

Cell–cell contact between pancreatic ?-cells is important for maintaining survival and normal insulin secretion. Various techniques have been developed to promote cell–cell contact between ?-cells, but a simple yet robust method that affords precise control over three-dimensional (3D) ?-cell cluster size has not been demonstrated. To address this need, we developed a poly(ethylene glycol) (PEG) hydrogel microwell platform using photolithography. This microwell cell-culture platform promotes the formation of 3D ?-cell aggregates of defined sizes from 25 to 210??m in diameter. Using this platform, mouse insulinoma 6 (MIN6) ?-cells formed aggregates with cell–cell adherin junctions. These naturally formed cell aggregates with controllable sizes can be removed from the microwells for macroencapsulation, implantation, or other biological assays. When removed and subsequently encapsulated in PEG hydrogels, the aggregated cell clusters demonstrated improved cellular viability (>90%) over 7 days in culture, while the ?-cells encapsulated as single cells maintained only 20% viability. Aggregated MIN6 cells also exhibited more than fourfold higher insulin secretion in response to a glucose challenge compared with encapsulated single ?-cells. Further, the cell aggregates stained positively for E-cadherin, indicative of the formation of cell junctions. Using this hydrogel microwell cell-culture method, viable and functional ?-cell aggregates of specific sizes were created, providing a platform from which other biologically relevant questions may be answered.

Bernard, Abigail B.; Lin, Chien-Chi

2012-01-01

236

Comparison of two rapid streptococcal antigen detection assays with culture for diagnosis of streptococcal pharyngitis.  

PubMed

In this study, 801 pharyngeal specimens were cultured for group A streptococci and tested with the Biostar Strep A Optical Immunoassay (Strep A OIA). The respective sensitivities and specificities were as follows: culture, 97.1 and 100%; Strep A OIA, 91.5 and 94.8%. Of the 801 specimens, 597 were also tested with the Abbott TestPack Strep A Assay (TP-ST). For those specimens tested by all three methods, the respective sensitivities and specificities were as follows: culture, 98.1 and 100%; Strep A OIA, 92.3 and 95.4%; and TP-ST, 79.4 and 100%. The Strep A OIA is significantly more sensitive than TP-ST and compares favorably with culture. PMID:7615768

Heiter, B J; Bourbeau, P P

1995-05-01

237

Polyclonal Activation of Bone-Marrow-Derived Lymphocytes from Human Peripheral Blood Measured by a Direct Plaque-Forming Cell Assay  

Microsoft Academic Search

A culture and assay system for the stimulation of human peripheral blood lymphocytes with polyclonal activators of bone-marrow-derived lymphocytes (B cells), such as pokeweed mitogen and Escherichia coli lipopolysaccharide, and subsequent measurement of single cell antibody production by a hemolysis-in-gel direct plaque-forming cell assay against sheep erythrocytes has been established. The critical culture requirements have been delineated and a new

Anthony S. Fauci; Karen R. Pratt

1976-01-01

238

Nanopillar based electrochemical biosensor for monitoring microfluidic based cell culture  

NASA Astrophysics Data System (ADS)

In-vitro assays using cultured cells have been widely performed for studying many aspects of cell biology and cell physiology. These assays also form the basis of cell based sensing. Presently, analysis procedures on cell cultures are done using techniques that are not integrated with the cell culture system. This approach makes continuous and real-time in-vitro measurements difficult. It is well known that the availability of continuous online measurements for extended periods of time will help provide a better understanding and will give better insight into cell physiological events. With this motivation we developed a highly sensitive, selective and stable microfluidic electrochemical glucose biosensor to make continuous glucose measurements in cell culture media. The performance of the microfluidic biosensor was enhanced by adding 3D nanopillars to the electrode surfaces. The microfluidic glucose biosensor consisted of three electrodes---Enzyme electrode, Working electrode, and Counter electrode. All these electrodes were enhanced with nanopillars and were optimized in their respective own ways to obtain an effective and stable biosensing device in cell culture media. For example, the 'Enzyme electrode' was optimized for enzyme immobilization via either a polypyrrole-based or a self-assembled-monolayer-based immobilization method, and the 'Working electrode' was modified with Prussian Blue or electropolymerized Neutral Red to reduce the working potential and also the interference from other interacting electro-active species. The complete microfluidic biosensor was tested for its ability to monitor glucose concentration changes in cell culture media. The significance of this work is multifold. First, the developed device may find applications in continuous and real-time measurements of glucose concentrations in in-vitro cell cultures. Second, the development of a microfluidic biosensor will bring technical know-how toward constructing continuous glucose monitoring devices. Third, the methods used to develop 3D electrodes incorporated with nanopillars can be used for other applications such as neural probes, fuel cells, solar cells etc., and finally, the knowledge obtained from the immobilization of enzymes onto nanostructures sheds some new insight into nanomaterial/biomolecule interactions.

Gangadharan, Rajan

239

HUMN project: detailed description of the scoring criteria for the cytokinesis-block micronucleus assay using isolated human lymphocyte cultures.  

PubMed

Criteria for scoring micronuclei and nucleoplasmic bridges in binucleated cells in the cytokinesis-block micronucleus assay for isolated human lymphocyte cultures are described in detail. Morphological characteristics of mononucleated cells, binucleated cells, and multinucleated cells as well as necrotic and apoptotic cells and nuclear buds are also described. These criteria are illustrated by a series of schematic diagrams as well as a comprehensive set of colour photographs that are of practical assistance during the scoring of slides. These scoring criteria, diagrams and photographs have been used in a HUman MicronNucleus (HUMN) project inter-laboratory slide-scoring exercise to evaluate the extent of variability that can be attributable to individual scorers and individual laboratories when measuring the frequency of micronuclei and nucleoplasmic bridges in binucleated cells as well as the nuclear division index. The results of the latter study are described in an accompanying paper. It is expected that these scoring criteria will assist in the development of a procedure for calibrating scorers and laboratories so that results from different laboratories for the cytokinesis-block micronucleus assay may be more comparable in the future. PMID:12504755

Fenech, M; Chang, W P; Kirsch-Volders, M; Holland, N; Bonassi, S; Zeiger, E

2003-01-10

240

DNA damage in exfoliated buccal cells of smokers assessed by the single cell gel electrophoresis assay  

Microsoft Academic Search

The alkaline single-cell gel electrophoresis assay or comet assay is a sensitive and rapid method for DNA strand breaks and detection of alkali labile sites at the single cell level, it further provides information on the presence of damage among individual cells. In this paper we explore the use of this technique utilizing exfoliated buccal mucosa cells from non-smokers (9

E. Rojas; M. Valverde; M. Sordo; P. Ostrosky-Wegman

1996-01-01

241

21 CFR 864.2280 - Cultured animal and human cells.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Cultured animal and human cells. 864.2280 Section 864...864.2280 Cultured animal and human cells. (a) Identification. Cultured animal and human cells are in vitro cultivated cell...

2009-04-01

242

21 CFR 864.2280 - Cultured animal and human cells.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Cultured animal and human cells. 864.2280 Section 864...864.2280 Cultured animal and human cells. (a) Identification. Cultured animal and human cells are in vitro cultivated cell...

2010-04-01

243

Flow cytometric analysis of protein content in Taxus protoplasts and single cells as compared to aggregated suspension cultures  

Microsoft Academic Search

Plant suspension cultures are highly aggregated, preventing the direct application of flow cytometry for the study of population dynamics. The utility of single cells to accurately represent aggregated suspension cultures was tested through the analysis of total protein content. Specifically, protein content of two Taxus cuspidata suspension culture lines was studied using the Bradford assay for aggregated suspension cultures, and

Michael C. Naill; Susan C. Roberts

2005-01-01

244

The cell-mediated cytotoxic response to influenza vaccination using an assay for granzyme B activity.  

PubMed

The measurement of cytotoxic T lymphocyte (CTL) activity through 51Cr assays is a very labour intensive method for studying cytotoxicity in human CTL due to the necessary preparation of autologous targets for the assay. An assay for granzyme B, one of a family of serine proteinases implicated in the 'lethal hit' that leads to target cell lysis, is an alternative simple measure of CTL activation. We measured granzyme B activity using its both preferred and unique substrate tert-butyloxycarbonyl-Ala-Ala-Asp-thiobenzyl ester (BAADT) in peripheral blood mononuclear cells (PBMC) obtained from influenza vaccinated subjects, and stimulated with live virus. We found that granzyme B activity increases in parallel and correlates with cytolytic activity as measured by 51Cr release assays in these virus-stimulated PBMC cultures. The assay was then used to measure the cell-mediated cytotoxic response to influenza vaccination in ten healthy elderly subjects. Peak granzyme B activity (day 6) was measured in lysates of PBMC stimulated with influenza virus, obtained from study participants before and after vaccination. We found a significant increase in granzyme B activity from pre-vaccination levels to 4 weeks post vaccination (pre=2.77 U/mg protein, post=7.23 U/mg protein, p=0.002) and a subsequent decline in the activity measured at 12 weeks post vaccination (4.34 U/mg protein, p=0.0007). Due to its substrate specificity which is unique within the family of serine proteases, this assay is highly specific for granzyme B. The assay also avoids the potential hazard of radioactivity (51Cr) in the clinical laboratory and the need for a gamma counter. The assay of granzyme B activity, therefore, provides a simple, specific and responsive method for measuring changes in cell-mediated cytotoxic activity resulting from influenza vaccination. PMID:8601703

McElhaney, J E; Pinkoski, M J; Upshaw, C M; Bleackley, R C

1996-03-28

245

Assay for inorganic pyrophosphate in chondrocyte culture using anion-exchange high-performance liquid chromatography and radioactive orthophosphate labeling  

SciTech Connect

A method is described for determination of inorganic pyrophosphate (PPi) in cell culture medium and in rabbit articular chondrocytes grown in the presence of radioactive orthophosphate (/sup 32/Pi). Intra- and extracellular /sup 32/PPi formed was measured using high-performance liquid chromatographic (HPLC) separation of the PPi from orthophosphate (Pi) and other phosphate-containing compounds. The chromatographic separation on a weak anion-exchange column is based on the extent to which various phosphate compounds form complexes with Mg2+ at low pH and the rate at which such formation occurs. These complexes are eluted more readily than the uncomplexed compounds. Best results were obtained using a simultaneous gradient of Mg2+ ions and ionic strength. In this case separation of small amounts of PPi from a large excess of Pi was possible without prior removal of Pi or extraction of the PPi fraction. The assay is also useful for measurement of inorganic pyrophosphatase activity. The sensitivity of the assay depends on the specific activity of the added /sup 32/Pi and on the culture conditions, but is comparable with the most sensitive of the enzymatic assays. Sample preparation, particularly deproteinization, proved to be of importance. The losses of PPi which occur during procedures of this sort due to hydrolysis and coprecipitation were quantitated.

Prins, A.P.; Kiljan, E.; v.d. Stadt, R.J.; v.d. Korst, J.K.

1986-02-01

246

Calcium deposition in osteoarthritic meniscus and meniscal cell culture  

PubMed Central

Introduction Calcium crystals exist in the knee joint fluid of up to 65% of osteoarthritis (OA) patients and the presence of these calcium crystals correlates with the radiographic evidence of hyaline cartilaginous degeneration. This study sought to examine calcium deposition in OA meniscus and to investigate OA meniscal cell-mediated calcium deposition. The hypothesis was that OA meniscal cells may play a role in pathological meniscal calcification. Methods Studies were approved by our human subjects Institutional Review Board. Menisci were collected during joint replacement surgeries for OA patients and during limb amputation surgeries for osteosarcoma patients. Calcium deposits in menisci were examined by alizarin red staining. Expression of genes involved in biomineralization in OA meniscal cells was examined by microarray and real-time RT-PCR. Cell-mediated calcium deposition in monolayer culture of meniscal cells was examined using an ATP-induced 45calcium deposition assay. Results Calcium depositions were detected in OA menisci but not in normal menisci. The expression of several genes involved in biomineralization including ENPP1 and ANKH was upregulated in OA meniscal cells. Consistently, ATP-induced calcium deposition in the monolayer culture of OA meniscal cells was much higher than that in the monolayer culture of control meniscal cells. Conclusions Calcium deposition is common in OA menisci. OA meniscal cells calcify more readily than normal meniscal cells. Pathological meniscal calcification, which may alter the biomechanical properties of the knee meniscus, is potentially an important contributory factor to OA.

2010-01-01

247

Antibody inhibition of human cytomegalovirus spread in epithelial cell cultures.  

PubMed

Anti-cytomegalovirus (CMV) antibodies reduce the incidence of CMV transmission and ameliorate the severity of CMV-associated disease. Neutralizing activity, measured as the ability of antibodies to prevent entry of cell-free virus, is an important component of natural immunity. However, in vivo CMV amplification may occur mainly via spread between adjacent cells within tissues. Thus, inhibition of cell-to-cell spread may be important when evaluating therapeutic antibodies or humoral responses to infection or immunization. In vitro CMV cell-to-cell spread is largely resistant to antibodies in fibroblast cultures but sensitive in endothelial cell cultures. In the present study antibodies in CMV hyperimmuneglobulin or seropositive human sera inhibited CMV cell-to-cell spread in epithelial cell cultures. Spread inhibition activity was quantitated with a GFP reporter assay employing GFP-tagged epithelialtropic variants of CMV strains Towne or AD169. Measurement of spread inhibition provides an additional parameter for the evaluation of candidate vaccines or immunotherapeutics and to further characterize the role of antibodies in controlling CMV transmission and disease. PMID:23669101

Cui, Xiaohong; Lee, Ronzo; Adler, Stuart P; McVoy, Michael A

2013-05-10

248

Medium and Culture of Embryonic Stem Cells.  

National Technical Information Service (NTIS)

Previous methods for culturing human embryonic stem cells have required either fibroblast feeder cells or a medium which has been exposed to fibroblast feeder cells in order to maintain the stem cells in an undifferentiated state. It has now been found th...

J. A. Thomson T. Ludwig

2005-01-01

249

Longterm cultures of sheep thyroid cells.  

PubMed

A thyroid tissue culture system has been established in which follicular morphology can be preserved for at least 30 days. The system is highly dependent on whether or not the medium supporting the cells is changed during the culture period. The high levels of TSH (40 mU/ml) normally used in thyroid culture systems enhance follicular morphology but are not a prerequisite for differentiation. In the absence of medium changes follicular morphology improves for up to 20 days after initiation of the culture. Thereafter, the cells die unless the medium is changed. If differentiation is to be preserved after 20 days the medium into which the cells are transferred must be "conditioned" by preincubation with thryoid cultures. Regular medium changes into fresh medium causes the cultures to lose their differentiated characteristics and revert to a conventional monolayer. The capacity of these cultures to trap iodide has been quantified using a new method. The method is based on comparison of the 125I--iodide retained by thyroid cells with that retained in a undifferentiated established cell line (CHO--K1). The results demonstrated that trapping can be preserved for at least 20 days in cells cultured in the presence of TSH, provided the medium is not changed; and that under appropriate conditions the cells can trap iodide even in the absence of TSH stimulation. The extent to which the above cultures proliferate is also investigated. At the relatively high innoculation of cells used in primary cultures little proliferation takes place even when the cells are stimulated by TSH. However, regular medium changed induce some growth. In the absence of medium changes the cells die after 15-20 days. Those grown in the presence of TSH live slightly longer than those grown in its absence. Subculturing thyroid cells and innoculating them at low densities in Petri dishes leads to substantial cell proliferation whether or not TSH is present. The doubling time of cells in these cultures is the order of 1 to 2 days. The population resulting from this growth exhibit both epithelial and fibroblast like morphology although the former predominates. When cells from primary thryoid cultures are reseeded at very low concentrations (approximately 10(3) cells/Petri dish) about 3-10 per cent of the population give rise to viable macroscopic clones. PMID:6996408

O'Connor, M K; Malone, J F; Cullen, M J

1980-01-01

250

Cell culturing of human and murine microglia cell lines.  

PubMed

Despite the fact that microglia cells were first described almost a century ago, microglia-derived immortalized cell lines have only been established in the last two decades. One should be aware of their limitations but also of their advantages. Cell lines offer a potentially powerful tool to investigate some functional aspects of microglia. Cell culturing of human and murine microglia cell lines will be described in this chapter. It includes a presentation of equipment needed, cell culture medium and supplements, cell culture monitoring, and a protocol describing the steps for subculturing of microglia cell lines. PMID:23813364

Rodhe, Johanna

2013-01-01

251

Measuring antimicrobial peptide activity on epithelial surfaces in cell culture.  

PubMed

To more accurately assess the activity and role of epithelial cell-derived antimicrobial peptides in their native settings, it is essential to perform assays at the surfaces under relevant conditions. In order to carry this out, we utilize three-dimensional cultures of airway and gingival epithelium, which are grown at an air-liquid interface. Under these conditions, the cultures can be subjected to challenge with a variety of factors known to cause an increase in antimicrobial peptide gene expression. The functional relevance of this induction can then be assessed by quantifying antibacterial activity either directly on the surface of the cells or using the fluid secreted onto the apical surface of the cultures. The relative contribution of the peptides can also be measured by pre-incubation of the secreted fluid with specific inhibitory antibodies. Thus, a relatively inexpensive in vitro model can be used to evaluate the role of antimicrobial peptides in mucosal epithelium. PMID:20094876

Diamond, Gill; Yim, Sunghan; Rigo, Isaura; McMahon, Laura

2010-01-01

252

Feeder cell cultures for zebrafish embryonal cells in vitro.  

PubMed

Use of fibroblast cells derived from mouse embryos as feeder layers was one of the major steps leading to the establishment of pluripotential mouse embryonal stem (ES) cells in culture. In attempts to obtain a culture of pluripotential ES cells from zebrafish, a culture of fibroblastoid cells, designated zebrafish embryo fibroblast (ZEF), was established from early gastrula stage zebrafish embryos for use as feeder layer. In primary cultures initiated from early embryos of zebrafish without feeder layers, melanocytes appeared on the second day of culture. In contrast, melanogenesis was markedly suppressed in cocultures containing confluent monolayers of ZEF or Buffalo rat liver (BRL) cells. BRL cells are commonly used feeder layer cells for mouse ES cells. Suppression of melanogenesis was not observed in primary cultures initiated in medium containing human recombinant differentiation-inhibiting activity (DIA) or in medium conditioned by cultures of BRL feeder cells. Proliferation of zebrafish embryonal cells was enhanced significantly in cocultures with either feeder layer. Zebrafish embryonal cells cocultured short-term on ZEF and BRL feeder layers gave rise to melanocytes and formed embryoid body-like structures when removed from feeder layers and cultured in suspension, suggesting that the cells remained pluripotent in culture. PMID:7749465

Sun, L; Bradford, C S; Barnes, D W

1995-03-01

253

Processing of primary brain tumor tissue for stem cell assays and flow sorting.  

PubMed

Brain tumors are typically comprised of morphologically diverse cells that express a variety of neural lineage markers. Only a relatively small fraction of cells in the tumor with stem cell properties, termed brain tumor initiating cells (BTICs), possess an ability to differentiate along multiple lineages, self-renew, and initiate tumors in vivo. We applied culture conditions originally used for normal neural stem cells (NSCs) to a variety of human brain tumors and found that this culture method specifically selects for stem-like populations. Serum-free medium (NSC) allows for the maintenance of an undifferentiated stem cell state, and the addition of bFGF and EGF allows for the proliferation of multi-potent, self-renewing, and expandable tumorspheres. To further characterize each tumor's BTIC population, we evaluate cell surface markers by flow cytometry. We may also sort populations of interest for more specific characterization. Self-renewal assays are performed on single BTICs sorted into 96 well plates; the formation of tumorspheres following incubation at 37 °C indicates the presence of a stem or progenitor cell. Multiple cell numbers of a particular population can also be sorted in different wells for limiting dilution analysis, to analyze self-renewal capacity. We can also study differential gene expression within a particular cell population by using single cell RT-PCR. The following protocols describe our procedures for the dissociation and culturing of primary human samples to enrich for BTIC populations, as well as the dissociation of tumorspheres. Also included are protocols for staining for flow cytometry analysis or sorting, self-renewal assays, and single cell RT-PCR. PMID:23051935

Venugopal, Chitra; McFarlane, Nicole M; Nolte, Sara; Manoranjan, Branavan; Singh, Sheila K

2012-09-25

254

A spheroid-based 3-D culture model for pancreatic cancer drug testing, using the acid phosphatase assay.  

PubMed

Current therapy for pancreatic cancer is multimodal, involving surgery and chemotherapy. However, development of pancreatic cancer therapies requires a thorough evaluation of drug efficacy in vitro before animal testing and subsequent clinical trials. Compared to two-dimensional culture of cell monolayer, three-dimensional (3-D) models more closely mimic native tissues, since the tumor microenvironment established in 3-D models often plays a significant role in cancer progression and cellular responses to the drugs. Accumulating evidence has highlighted the benefits of 3-D in vitro models of various cancers. In the present study, we have developed a spheroid-based, 3-D culture of pancreatic cancer cell lines MIAPaCa-2 and PANC-1 for pancreatic drug testing, using the acid phosphatase assay. Drug efficacy testing showed that spheroids had much higher drug resistance than monolayers. This model, which is characteristically reproducible and easy and offers rapid handling, is the preferred choice for filling the gap between monolayer cell cultures and in vivo models in the process of drug development and testing for pancreatic cancer. PMID:23903680

Wen, Z; Liao, Q; Hu, Y; You, L; Zhou, L; Zhao, Y

2013-07-22

255

Quantitative detection of cell culture Mycoplasmas by a one step polymerase chain reaction method  

Microsoft Academic Search

A rapid, sensitive assay was developed that can detect the six species of Mycoplasmas that account for the vast majority of cell culture infections. This assay, a modification of the method published by Wong-Lee & Lovett [1], allows direct evaluation of culture medium by a single-step PCR method that utilizes primers complementary to conserved 16S rRNA sequences. Extensive testing of

Edward Otto; Celeste Zalewski; Michele Kaloss; Richard A. Del Giudice; Roberta Gardella; Gerard J. McGarrity

1996-01-01

256

Culture and characterisation of epithelial cells from human pterygia  

PubMed Central

BACKGROUND/AIMS—Pterygia are a common disorder of the ocular surface. The disease represents a chronic fibrovascular and degenerative process thought to originate at the conjunctival-corneal junction, where altered limbal stem cells are proposed to be the cell of origin. Extensive epidemiological evidence exists to implicate ultraviolet B irradiation in the pathogenesis of pterygia. To date no animal or in vitro culture model has been developed to test such an hypothesis. The aim of this study was to establish and characterise a pure population of epithelial cells derived from pterygium tissue.?METHODS—Tissue specimens were obtained from patients undergoing pterygium excision. Explants were cultured in either serum free or serum supplemented medium. Primary and passaged cells were processed for light microscopy, analysed by flow cytometry, and characterised immunohistochemically using specific antibodies.?RESULTS—In serum free culture, cuboidal cells with typical morphology of epithelial cells migrated from the pterygium explants from 3 days onwards and eventually formed a cohesive monolayer. Passaged cells consisted of 98.4% cytokeratin positive cells and demonstrated immunoreactivity for multiple cytokeratins, including AE1, AE3, AE5, but were negative for AE8. These cells also expressed an epithelial specific antigen, together with vimentin and mucin, as did epithelial cells in sections of pterygia.?CONCLUSIONS—A relatively simple method of isolating pterygium epithelial cells has been established. Cultured pterygium epithelial cells are phenotypically and functionally similar to their in vivo counterparts with respect to keratin, vimentin, and mucin expression. In vitro assays using these cells may aid in elucidating the pathogenesis of pterygia.??

Di, G; Tedla, N.; Kumar, R.; McCluskey, P.; Lloyd, A.; Coroneo, M.; Wakefield, D.

1999-01-01

257

A cell-based assay for screening spindle checkpoint inhibitors.  

PubMed

In eukaryotes, the spindle checkpoint acts as a surveillance mechanism that ensures faithful chromosome segregation. The spindle checkpoint prevents premature separation of sister chromatids and the onset of anaphase until every chromosome is properly attached to the mitotic spindle. Tumorigenesis might result from generation of aneuploidy by dysfunction of the spindle checkpoint. Differences of the checkpoint system in normal cells versus tumor cells might provide a new opportunity in cancer drug development; therefore, efforts to identify the spindle checkpoint inhibitors have been fostered. Based on spindle checkpoint inhibitors being able to induce cells to exit mitotic arrest caused by microtubule drug treatment, we developed a cell-based assay to screen compounds that were potential spindle checkpoint inhibitors. This assay was validated with a known spindle checkpoint inhibitor and was easy to adapt to a large-scale screening. It also had the advantages of being high in sensitivity and low in cost. PMID:22352901

Wu, Zhen Hua; Hu, Long Yu; Xu, Da Qian; Li, Xiaotong

2012-02-21

258

A Cell-Based Assay for Screening Spindle Checkpoint Inhibitors  

PubMed Central

Abstract In eukaryotes, the spindle checkpoint acts as a surveillance mechanism that ensures faithful chromosome segregation. The spindle checkpoint prevents premature separation of sister chromatids and the onset of anaphase until every chromosome is properly attached to the mitotic spindle. Tumorigenesis might result from generation of aneuploidy by dysfunction of the spindle checkpoint. Differences of the checkpoint system in normal cells versus tumor cells might provide a new opportunity in cancer drug development; therefore, efforts to identify the spindle checkpoint inhibitors have been fostered. Based on spindle checkpoint inhibitors being able to induce cells to exit mitotic arrest caused by microtubule drug treatment, we developed a cell-based assay to screen compounds that were potential spindle checkpoint inhibitors. This assay was validated with a known spindle checkpoint inhibitor and was easy to adapt to a large-scale screening. It also had the advantages of being high in sensitivity and low in cost.

Wu, Zhen Hua; Hu, Long Yu; Xu, Da Qian

2012-01-01

259

MAMMALIAN CELL GENE MUTATION ASSAYS WORKING GROUP REPORT  

EPA Science Inventory

Mammalian cell gene mutation assays have been used for many years and the diversity of the available systems attests to the varied methods found to grow mammalian dells and detect mutations. s part of the International Workshop on Standardization of Genotoxicity Test Procedures, ...

260

Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) assay  

EPA Science Inventory

The Embryonic Stem Cell Test (EST) is an assay which evaluates xenobiotic-induced effects using three endpoints: mouse embryonic stem cell (mESC) differentiation, mESC viability, and 3T3-cell viability. Our research goal was to develop an improved high-throughput assay by establi...

261

Cell culture processes for monoclonal antibody production  

PubMed Central

Animal cell culture technology has advanced significantly over the last few decades and is now generally considered a reliable, robust and relatively mature technology. A range of biotherapeutics are currently synthesized using cell culture methods in large scale manufacturing facilities that produce products for both commercial use and clinical studies. The robust implementation of this technology requires optimization of a number of variables, including (1) cell lines capable of synthesizing the required molecules at high productivities that ensure low operating cost; (2) culture media and bioreactor culture conditions that achieve both the requisite productivity and meet product quality specifications; (3) appropriate on-line and off-line sensors capable of providing information that enhances process control; and (4) good understanding of culture performance at different scales to ensure smooth scale-up. Successful implementation also requires appropriate strategies for process development, scale-up and process characterization and validation that enable robust operation and ensure compliance with current regulations. This review provides an overview of the state-of-the art technology in key aspects of cell culture, e.g., generation of highly productive cell lines and optimization of cell culture process conditions. We also summarize the current thinking on appropriate process development strategies and process advances that might affect process development.

Li, Feng; Vijayasankaran, Natarajan; Shen, Amy (Yijuan); Kiss, Robert

2010-01-01

262

Bioprocessing technology for plant cell suspension cultures  

Microsoft Academic Search

Considering various forms of in vitro plant tissue cultures, cell suspension culture is most amenable to large-scale production\\u000a of natural compounds, owing primarily to its superior culture homogeneity. This fact has already been demonstrated in several\\u000a largescale applications, including the commercial shikonin process. The scope of this work is to review the state of the art\\u000a in bioprocessing technologies pertinent

Wei wen Su

1995-01-01

263

Development of culture-based serological assays to diagnose Babesia divergens infections.  

PubMed

Babesioses are hematic tick-borne diseases that induce malaria-like disorders in domestic, wild animals, and humans. Although indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) commercial kits are available to test the presence of antibodies against most Babesia species, no kit exists to serologically diagnose the infections due to Babesia divergens, one of the most important zoonotic species. To fill this gap and to develop assays to detect animal and human infections, in vitro cultures (microaerophilous stationary phase system) of B. divergens were organized. Infected erythrocytes were adsorbed as corpuscular antigen (CA) on IFAT slides and ELISA microwells. The supernatant medium of the cultures (metabolic antigen, MA) was collected and employed in ELISA and western blot (WB) assays. B. divergens was also used to produce positive sera in Meriones unguiculatus and to infect a calf. Serological tests were set up with sera from experimentally/naturally infected animals, and possible cross-reactions were evaluated using heterologous sera from cattle positive to other piroplasms. Sera from clinically healthy people at risk of infection were also tested. As expected, assays based on the purified MAs from in vitro cultures proved more sensitive and specific than CA-IFAT and CA-ELISA. In fact, MA-ELISA provided satisfactory performances (even if 8.4%-15.7% cross-reactions were evidenced), and the WB developed proved totally sensitive and specific. WB indicated as immunodominant antigens two major protein bands at 33 and 37?kDa, which were also evidenced in 2.2% of the human sera tested, proving the parasite transmission to humans also in Italy. PMID:21995263

Gabrielli, Simona; Galuppi, Roberta; Marcer, Federica; Marini, Carla; Tampieri, Maria Paola; Moretti, Annabella; Pietrobelli, Mario; Cancrini, Gabriella

2011-10-13

264

Galactose-1-phosphate uridyltransferase in cultured cells.  

PubMed

A method to measure the enzyme galactose-1-phosphate uridyltransferase in cultured cells is described. The optimun pH was 8.7 and no enzyme activity was found without preincubation with dithiothreitol. The KM values for Gal-1-P and UDPG for the wild type enzyme were found to be 0.2 mM and 0.08 mM, respectively. Values for the Duarte variant were found to be identical. No significant change in enzyme activity with time after subculture was found in either cultured skin fibroblasts or cultured amniotic fluid cells. Different transferase genotypes were clearly distinguished and reference range established. Transferase levels found in normal cultured amniotic fluid cells were the same as in normal cultured skin fibroblasts. The results of a prenatal diagnosis was obtained within 3 weeks of amniocentesis. PMID:11916

Monk, A M; Holton, J B

1976-12-01

265

Optimization of a dendritic cell-based assay for the in vitro priming of naďve human CD4+ T cells.  

PubMed

Methods to prime human CD4(+) T cells in vitro would be of significant value for the pre-clinical evaluation of vaccine candidates and other immunotherapeutics. However, to date, there is no reliable method for the induction of primary human T cell responses in the laboratory. Here, we optimized a culture strategy incorporating highly purified lymphocytes and dendritic cells, in the absence of any exogenous growth factors, for the in vitro sensitization of naďve CD4(+) T cells against a variety of protein antigens. This fully autologous approach, which was superior to the more traditional PBMC assay for supporting the induction of primary human T helper cell responses in culture, elicited effector cells capable of producing a variety of Th cytokines, including IFNgamma, TNFalpha, IL-2, IL-5, IL-17 and IL-21, and memory cells that could be restimulated multiple times with a specific antigen. Through simple modifications to this culture method, we evaluated the role of dendritic cell maturation state and regulatory T cells on the sensitization of naďve T helper cells, which highlights its utility for addressing basic questions of human immunobiology. Finally, using the formulated yellow fever vaccine, YF-VAX (R), we provide a proof-of-concept demonstration of the utility of the system for evaluating the T cell immunogenicity of vaccine candidates in a pre-clinical setting. PMID:19925804

Moser, Janice M; Sassano, Emily R; Leistritz, Del C; Eatrides, Jennifer M; Phogat, Sanjay; Koff, Wayne; Drake, Donald R

2009-11-17

266

21 CFR 864.2280 - Cultured animal and human cells.  

Code of Federal Regulations, 2010 CFR

...2012-04-01 false Cultured animal and human cells. 864.2280 Section 864.2280... HEMATOLOGY AND PATHOLOGY DEVICES Cell And Tissue Culture Products § 864.2280 Cultured animal and human cells. (a) Identification....

2012-04-01

267

Culturability and Coexistence of Colony-Forming and Single-Cell Marine Bacterioplankton  

Microsoft Academic Search

Culturability and coexistence of bacterioplankton exhibiting different life strategies were investigated in the Baltic Sea and Skagerrak Sea. Bacterial numbers were estimated using a dilution-to-extinction culturing assay (DCA) and calculated as the most probable number, based on six different methods to detect bacterial growth in the DCA. Irrespective of the method used to detect growth, the fraction of multiplying cells

Karin Simu; Karin Holmfeldt; Ulla Li Zweifel; A. Hagstrom

2005-01-01

268

Genotoxic effects of sunlight-activated waste water in cultured mammalian cells  

Microsoft Academic Search

Cultured Chinese hamster ovary cells were incubated with dilutions of an oil shale retort process water and exposed to nautral sunlight. An enhancement of sevenfold to ninefold was seen in photoinduced cytotoxicity (by a colony-forming assay) and mutagenicity (at the hypoxanthine phosphoribosyltransferase (HPRT) locus) for cells pretreated with the process water compared to effects seen in cells exposed to sunlight

G. F. Strniste; D. J. Chen; R. T. Okinaka

1982-01-01

269

Verbascoside production by plant cell cultures  

Microsoft Academic Search

Verbascoside was found to be produced in all calli derived from eleven species that contained the compound in their leaves. Cell suspension cultures were also established in three species, i.e., Leucosceptrum japonicum f. barbinerve, Syringa josikaea, and Sy. vulgaris, all of which were found to produce verbascoside at more than 1 g\\/l. Of the three species, suspension cultures of L.

Nobuyuki Inagaki; Hiroaki Nishimura; Minoru Okada; Hiroshi Mitsuhashi

1991-01-01

270

Prion protein lacks robust cytoprotective activity in cultured cells  

PubMed Central

Background The physiological function of the cellular prion protein (PrPC) remains unknown. However, PrPC has been reported to possess a cytoprotective activity that prevents death of neurons and other cells after a toxic stimulus. To explore this effect further, we attempted to reproduce several of the assays in which a protective activity of PrP had been previously demonstrated in mammalian cells. Results In the first set of experiments, we found that PrP over-expression had a minimal effect on the death of MCF-7 breast carcinoma cells treated with TNF-? and Prn-p0/0 immortalized hippocampal neurons (HpL3-4 cells) subjected to serum deprivation. In the second set of assays, we observed only a small difference in viability between cerebellar granule neurons cultured from PrP-null and control mice in response to activation of endogenous or exogenous Bax. Conclusion Taken together, our results suggest either that cytoprotection is not a physiologically relevant activity of PrPC, or that PrPC-dependent protective pathways operative in vivo are not adequately modeled by these cell culture systems. We suggest that cell systems capable of mimicking the neurotoxic effects produced in transgenic mice by N-terminally deleted forms of PrP or Doppel may represent more useful tools for analyzing the cytoprotective function of PrPC.

Christensen, Heather M; Harris, David A

2008-01-01

271

Cytotoxicity of quantum dots assay on a microfluidic 3D-culture device based on modeling diffusion process between blood vessels and tissues.  

PubMed

In this work, a novel quantum dot (QD) cytotoxicity assay platform on a microfluidic three-dimensional (3D) culture device via imitating the diffusion process between blood vessels and tissues was developed. The device is composed of a main channel and two sets of cell culture chambers. The cell culture chambers were located at different distances from the main channel and were divided into "close chambers" and "far chambers". HepG2 cells were cultured in an agarose matrix under 3D conditions and kept at high viability for at least three days. Fluorescein sodium and fluorescein isothiocyanate conjugated to bovine serum albumin (FITC-BSA) were used as models to demonstrate the diffusion process between main channel and cell culture chambers. QD cytotoxicity was evaluated by determining cell apoptosis, intracellular reactive oxygen species (ROS) and glutathione (GSH) with specific fluorescence probes. Cell autophagy inhibitor 3-methyladenine (3-MA) could reduce cell apoptosis at low concentrations of QDs, which proves that cell autophagy plays a key role in QD cytotoxicity. The effect of a series of 3-MA solutions on cell apoptosis at QD concentration of 40 ?g mL(-1) was investigated, which showed that the percentage of cell apoptosis decreased ?15% from 0 to 12 mM 3-MA. The device shows potential as a high-throughput, low-cost and time-saving platform and constructs a more vivid biomimetic microenvironment for the QD cytotoxicity study. PMID:22836595

Wu, Jing; Chen, Qiushui; Liu, Wu; Zhang, Yandong; Lin, Jin-Ming

2012-07-27

272

High-throughput analysis of single hematopoietic stem cell proliferation in microfluidic cell culture arrays.  

PubMed

Heterogeneity in cell populations poses a major obstacle to understanding complex biological processes. Here we present a microfluidic platform containing thousands of nanoliter-scale chambers suitable for live-cell imaging studies of clonal cultures of nonadherent cells with precise control of the conditions, capabilities for in situ immunostaining and recovery of viable cells. We show that this platform mimics conventional cultures in reproducing the responses of various types of primitive mouse hematopoietic cells with retention of their functional properties, as demonstrated by subsequent in vitro and in vivo (transplantation) assays of recovered cells. The automated medium exchange of this system made it possible to define when Steel factor stimulation is first required by adult hematopoietic stem cells in vitro as the point of exit from quiescence. This technology will offer many new avenues to interrogate otherwise inaccessible mechanisms governing mammalian cell growth and fate decisions. PMID:21602799

Lecault, Véronique; Vaninsberghe, Michael; Sekulovic, Sanja; Knapp, David J H F; Wohrer, Stefan; Bowden, William; Viel, Francis; McLaughlin, Thomas; Jarandehei, Asefeh; Miller, Michelle; Falconnet, Didier; White, Adam K; Kent, David G; Copley, Michael R; Taghipour, Fariborz; Eaves, Connie J; Humphries, R Keith; Piret, James M; Hansen, Carl L

2011-05-22

273

Rotating cell culture systems for human cell culture: human trophoblast cells as a model.  

PubMed

The field of human trophoblast research aids in understanding the complex environment established during placentation. Due to the nature of these studies, human in vivo experimentation is impossible. A combination of primary cultures, explant cultures and trophoblast cell lines support our understanding of invasion of the uterine wall and remodeling of uterine spiral arteries by extravillous trophoblast cells (EVTs), which is required for successful establishment of pregnancy. Despite the wealth of knowledge gleaned from such models, it is accepted that in vitro cell culture models using EVT-like cell lines display altered cellular properties when compared to their in vivo counterparts. Cells cultured in the rotating cell culture system (RCCS) display morphological, phenotypic, and functional properties of EVT-like cell lines that more closely mimic differentiating in utero EVTs, with increased expression of genes mediating invasion (e.g. matrix metalloproteinases (MMPs)) and trophoblast differentiation. The Saint Georges Hospital Placental cell Line-4 (SGHPL-4) (kindly donated by Dr. Guy Whitley and Dr. Judith Cartwright) is an EVT-like cell line that was used for testing in the RCCS. The design of the RCCS culture vessel is based on the principle that organs and tissues function in a three-dimensional (3-D) environment. Due to the dynamic culture conditions in the vessel, including conditions of physiologically relevant shear, cells grown in three dimensions form aggregates based on natural cellular affinities and differentiate into organotypic tissue-like assemblies. The maintenance of a fluid orbit provides a low-shear, low-turbulence environment similar to conditions found in vivo. Sedimentation of the cultured cells is countered by adjusting the rotation speed of the RCCS to ensure a constant free-fall of cells. Gas exchange occurs through a permeable hydrophobic membrane located on the back of the bioreactor. Like their parental tissue in vivo, RCCS-grown cells are able to respond to chemical and molecular gradients in three dimensions (i.e. at their apical, basal, and lateral surfaces) because they are cultured on the surface of porous microcarrier beads. When grown as two-dimensional monolayers on impermeable surfaces like plastic, cells are deprived of this important communication at their basal surface. Consequently, the spatial constraints imposed by the environment profoundly affect how cells sense and decode signals from the surrounding microenvironment, thus implying an important role for the 3-D milieu. We have used the RCCS to engineer biologically meaningful 3-D models of various human epithelial tissues. Indeed, many previous reports have demonstrated that cells cultured in the RCCS can assume physiologically relevant phenotypes that have not been possible with other models. In summary, culture in the RCCS represents an easy, reproducible, high-throughput platform that provides large numbers of differentiated cells that are amenable to a variety of experimental manipulations. In the following protocol, using EVTs as an example, we clearly describe the steps required to three-dimensionally culture adherent cells in the RCCS. PMID:22297395

Zwezdaryk, Kevin J; Warner, Jessica A; Machado, Heather L; Morris, Cindy A; Höner zu Bentrup, Kerstin

2012-01-18

274

Novel patient cell-based HTS assay for identification of small molecules for a lysosomal storage disease.  

PubMed

Small molecules have been identified as potential therapeutic agents for lysosomal storage diseases (LSDs), inherited metabolic disorders caused by defects in proteins that result in lysosome dysfunctional. Some small molecules function assisting the folding of mutant misfolded lysosomal enzymes that are otherwise degraded in ER-associated degradation. The ultimate result is the enhancement of the residual enzymatic activity of the deficient enzyme. Most of the high throughput screening (HTS) assays developed to identify these molecules are single-target biochemical assays. Here we describe a cell-based assay using patient cell lines to identify small molecules that enhance the residual arylsulfatase A (ASA) activity found in patients with metachromatic leukodystrophy (MLD), a progressive neurodegenerative LSD. In order to generate sufficient cell lines for a large scale HTS, primary cultured fibroblasts from MLD patients were transformed using SV40 large T antigen. These SV40 transformed (SV40t) cells showed to conserve biochemical characteristics of the primary cells. Using a specific colorimetric substrate para-nitrocatechol sulfate (pNCS), detectable ASA residual activity were observed in primary and SV40t fibroblasts from a MLD patient (ASA-I179S) cultured in multi-well plates. A robust fluorescence ASA assay was developed in high-density 1,536-well plates using the traditional colorimetric pNCS substrate, whose product (pNC) acts as "plate fluorescence quencher" in white solid-bottom plates. The quantitative cell-based HTS assay for ASA generated strong statistical parameters when tested against a diverse small molecule collection. This cell-based assay approach can be used for several other LSDs and genetic disorders, especially those that rely on colorimetric substrates which traditionally present low sensitivity for assay-miniaturization. In addition, the quantitative cell-based HTS assay here developed using patient cells creates an opportunity to identify therapeutic small molecules in a disease-cellular environment where potentially disrupted pathways are exposed and available as targets. PMID:22216298

Geng, Haifeng; Whiteley, Grace; Ribbens, Jameson; Zheng, Wei; Southall, Noel; Hu, Xin; Marugan, Juan J; Ferrer, Marc; Maegawa, Gustavo H B

2011-12-21

275

Barnacle in vitro assays for biologically active substances: Toxicity and Settlement inhibition assays using mass cultured Balanus amphitrite amphitrite darwin  

Microsoft Academic Search

The development of non?toxic or non?polluting antifouling additives that can be formulated in practical coatings requires assays involving target organisms. Assays that test both for the effective and toxic concentrations of active compounds are useful. It is also desirable if the assay can provide information regarding the performance that can be expected if the compounds are incorporated into different matrices.

D. Rittschof; A. S. Clare; D. J. Gerhart; Sister Avelin Mary; J. Bonaventura

1992-01-01

276

Evaluation of Mixed Cell Types and 5-Iodo-2'-Deoxyuridine Treatment upon Plaque Assay Titers of Human Enteric Viruses (Journal Version).  

National Technical Information Service (NTIS)

Four continuous cell lines BGM, L-132, HEL-299, and RD were compared both when cultured separately and as mixtures for use in plaque assay titrations of human Adenovirus 1 and six human enterovirus serotypes. The effect of incubating these cell cultures i...

W. H. Benton C. J. Hurst

1986-01-01

277

A novel reporter gene assay for interferons based on CHO-K1 cells.  

PubMed

Interferons (IFNs) are cytokines playing an important role in the immune response and defence against viruses. They are widely used as biopharmaceuticals. Currently, the anti-viral assay (AVA) is the most commonly used bioassay for determining interferon potency. In the search for rapid and robust but reliable methods, reporter gene assays (RGA) appear to be the most promising approach, therefore we have designed a new reporter cell line, CHO-ISRE-SEAP, suitable for determination of type I interferon potency. Chinese hamster ovary (CHO-K1) cells were stably transfected with secretory alkaline phosphatase (SEAP) gene under the control of interferon stimulated response element (ISRE) promoter. The amount of SEAP in the cell culture medium can be easily measured colorimetrically and has been found to correlate with the amount of IFN added. The new assay is widely applicable for determination of type I IFNs, such as IFN-alpha, IFN-beta and IFN-omega, in research, development of IFN biopharmaceuticals, in batch release, etc. Interestingly, in this assay, IFN-beta shows approximately 6 times higher response than IFN-alpha, which makes it especially appropriate for measuring low levels of IFN-beta. Compared to other known RGAs, the novel CHO-ISRE-SEAP cell line-based RGA appears to have certain advantages with respect to cost and performance. PMID:18295789

Smilovi?, V; Caserman, S; Fonda, I; Gaberc-Porekar, V; Menart, V

2008-02-14

278

Quantification of Cells in Culture  

Microsoft Academic Search

\\u000a Cell enumeration using the hemocytometer is applicable when determining the number of cells in a suspension, and when the\\u000a number of samples to be analyzed is relatively small. Hemocytometry is also useful for determining the proportion of singly\\u000a dispersed cells in a suspension, and for estimating the frequency of viable cells.

Arleen Richardson; Sergey Fedoroff

279

Single cell and spheroid collagen type I invasion assay.  

PubMed

Tumor invasion is the outcome of a complex interplay between cancer cells and the stromal environment and requires the infiltration of a dense, cross-linked meshwork of collagen type I extracellular matrix. We use a membrane-free single-cell and spheroid-based complementary model to study cancer invasion through native collagen type I matrices. Cell morphology is preserved during the assays allowing real-time monitoring of invasion-induced changes in cell structure and F-actin organization. Combination of these models with computerized quantification permits the calculation of highly reproducible and operator-independent data. These assays are versatile in the use of fluorescent probes and have a flexible kinetic endpoint. Once the optimal experimental conditions are empirically determined, the collagen type I invasion assays can be used for preclinical validation of small-molecule inhibitors targeting invasion. Initiation and monitoring of the single-cell and spheroid invasion model can be achieved in 8 h (over 3 days) and in 14 h (over 5 days), respectively. PMID:24092429

De Wever, Olivier; Hendrix, An; De Boeck, Astrid; Eertmans, Frank; Westbroek, Wendy; Braems, Geert; Bracke, Marc E

2014-01-01

280

Culture and Manipulation of Embryonic Cells  

PubMed Central

The direct manipulation of embryonic cells is an important tool for addressing key questions in cell and developmental biology. C. elegans is relatively unique among genetic model systems in being amenable to manipulation of embryonic cells. Embryonic cell manipulation has allowed the identification of cell interactions by direct means, and it has been an important technique for dissecting mechanisms by which cell fates are specified, cell divisions are oriented, and morphogenesis is accomplished. Here, we present detailed methods for isolating, manipulating and culturing embryonic cells of C. elegans.

Edgar, Lois G.; Goldstein, Bob

2012-01-01

281

Activity of progesterone and anti-progestins in a rat mammary primary cell culture system  

Microsoft Academic Search

A primary culture system of virgin rat mammary epithelial cells, grown in a serum-free medium, was developed as a means of assaying the efficacy of compounds with known anti-progestational properties. Cells were grown in 24-well plates on hydrated collagen gels and could be cultured for at least seven days. Experiments were routinely stopped three days after overnight attachment of cells

J. A. Taylor; I. A. Forsyth; M.-W. Wang

1996-01-01

282

Cell Culture Derived AgMNPV Bioinsecticide: Biological Constraints and Bioprocess Issues  

Microsoft Academic Search

We have studied parameters for optimizing the Spodoptera frugiperda (Sf9) cell culture and viral infection for the production of Anticarsia gemmatalis multiple nucleopolyhedrosis virus (AgMNPV) polyhedra inclusion bodies (PIBs) in shaker-Schott or spinner bottles and bioreactors.\\u000a We have assayed the kLa of the systems, initial cell seeding, cell culture volume, dissolved oxygen (DO), multiplicity of infection (MOI), nutrients\\u000a consumption, and

Valeria M. Rodas; Fabiano H. Marques; Marcelo T. Honda; Daniela M. Soares; Soraia A. C. Jorge; Marta M. Antoniazzi; Claudia Medugno; Maria E. B. Castro; Bergmann M. Ribeiro; Marlinda L. Souza; Aldo Tonso; Carlos A. Pereira

2005-01-01

283

Integrated Bioprocessing for Plant Cell Cultures  

Microsoft Academic Search

Plant cell suspension culture has become the focus of much attention as a tool for the production of secondary metabolites\\u000a including paclitaxel, a well-known anticancer agent. Recently, it has also been regarded as one of the host systems for the\\u000a production of recombinant proteins. In order to produce phytochemicals using plant cell cultures, efficient processes must\\u000a be developed with adequate

Jeong-Woo Choi; Gyu Heon Cho; S ang Yo Byun; Dong-Il Kim

284

Oscillatory behavior of cells in tissue culture.  

NASA Astrophysics Data System (ADS)

Fibroblasts and epithelial cells organize themselves in distinct patterns in tissue culture which indicates that neighboring cells communicate. A striking example of such communication is the oscillatory behavior of Madin-Darby canine kidney (MDCK) cells reported here. These oscillations were discovered using a biosensor referred to as ECIS (Electric Cell-substrate Impedance Sensing). In this measurement cells are seeded out on a small electrode deposited at the bottom of a tissue culture well and immersed in ordinary culture medium. By measuring the changes in the impedance of the electrode as a function of time, many important properties of the cells on the electrode can be inferred, such as motion, morphology changes and membrane capacitance. The impedance oscillations of MDCK cells were observed with highly confluent cell layers, where the approximately 100 cells on the electrode acted in unison. The communication between cells can be demonstrated directly by a variation of the ECIS concept, where cells are cultured on two closely spaced electrodes. The impedance fluctuations are measured independently on each electrode and compared by using a cross-correlation function.

Giaever, Ivar; Linton, Michael F. A.; Keese, Charles R.

1998-03-01

285

Accuracy of an Accelerated, Culture-Based Assay for Detection of Group B Streptococcus  

PubMed Central

Objective. To determine the validity of a novel Group B Streptococcus (GBS) diagnostic assay for the detection of GBS in antepartum patients. Study Design. Women were screened for GBS colonization at 35 to 37 weeks of gestation. Three vaginal-rectal swabs were collected per patient; two were processed by traditional culture (commercial laboratory versus in-house culture), and the third was processed by an immunoblot-based test, in which a sample is placed over an antibody-coated nitrocellulose membrane, and after a six-hour culture, bound GBS is detected with a secondary antibody. Results. 356 patients were evaluated. Commercial processing revealed a GBS prevalence rate of 85/356 (23.6%). In-house culture provided a prevalence rate of 105/356 (29.5%). When the accelerated GBS test result was compared to the in-house GBS culture, it demonstrated a sensitivity of 97.1% and a specificity of 88.4%. Interobserver reliability for the novel GBS test was 88.2%. Conclusions. The accelerated GBS test provides a high level of validity for the detection of GBS colonization in antepartum patients within 6.5 hours and demonstrates a substantial agreement between observers.

Faro, Jonathan P.; Bishop, Karen; Riddle, Gerald; Ramirez, Mildred M.; Katz, Allan R.; Turrentine, Mark A.; Faro, Sebastian

2013-01-01

286

Cell culture systems for hepatitis C virus.  

PubMed

Due to the obligatory intracellular lifestyle of viruses, cell culture systems for efficient viral propagation are crucial to obtain a detailed understanding of the virus-host cell interaction. For hepatitis C virus (HCV) the development of permissive and authentic culture models continues to be a challenging task. The first efforts to culture HCV had limited success and range back to before the virus was molecularly cloned in 1989. Since then several major breakthroughs have gradually overcome limitations in culturing the virus and sequentially permitted analysis of viral RNA replication, cell entry, and ultimately the complete replication cycle in cultured cells in 2005. Until today, basic and applied HCV research greatly benefit from these tremendous efforts which spurred multiple complementary cell-based model systems for distinct steps of the HCV replication cycle. When used in combination they now permit deep insights into the fascinating biology of HCV and its interplay with the host cell. In fact, drug development has been much facilitated and our understanding of the molecular determinants of HCV replication has grown in parallel to these advances. Building on this groundwork and further refining our cellular models to better mimic the architecture, polarization and differentiation of natural hepatocytes should reveal novel unique aspects of HCV replication. Ultimately, models to culture primary HCV isolates across all genotypes may teach us important new lessons about viral functional adaptations that have evolved in exchange with its human host and that may explain the variable natural course of hepatitis C. PMID:23463196

Steinmann, Eike; Pietschmann, Thomas

2013-01-01

287

Bovine granulocyte/macrophage and erythroid colony culture: characteristics of the colonies and the assay systems.  

PubMed Central

Bovine bone marrow granulocyte/macrophage colonies were cultured in vitro in methyl cellulose and in plasma clots using bovine endotoxin-stimulated serum as a source of colony stimulating activity. The endotoxin-stimulated serum was four times as potent as the control serum in the methyl cellulose cultures. No significant increase in the number of colony forming units was observed when bovine marrow cells were maintained in suspension cultures for various periods prior to plating in methyl cellulose. The percentage of glass/plastic adherent cells in bovine marrow cells was observed to be 43% +/- 12 (SD). Benzidine positive erythroid colonies appeared in plasma clot cultures on day 4 and disappeared by day 9. No second population of erythroid colonies appeared either as a function of time or as a function of erythropoietin concentration. The optimum erythropoietin concentration for bovine erythroid cultures was found to be 1.0 unit/mL. A significant difference was observed between animals in their marrow capacity to produce erythroid colonies in culture but no significant difference was observed within individual animals over a period of three months. Images Fig. 3.

Kaaya, G P; Maxie, M G; Valli, V E; Losos, G J

1979-01-01

288

Nuclear binding assay for steroid receptor functionality in cancerous cells  

SciTech Connect

A method is described for rapidly assaying a tissue sample for nuclear antisteroid binding comprising: (a) fragmenting the tissue sample; (b) digesting the fragmented tissue with collagenase; (c) isolating the cells from the digested tissue; (d) incubating the cells with an amount of a radiolabelled antisteroid capable of complexing with and saturating the steroid receptors in the cells; (e) isolating the cellular nuclei; (f) measuring the bound radioactivity and the total DNA of the nuclei; and (g) comparing the amount of bound radioactivity and the total DNA to determine a measure of the total nuclear bound steroid receptors.

Spelsberg, T.C.

1989-02-21

289

Validation of the ALS Assay in Adult Patients with Culture Confirmed Pulmonary Tuberculosis  

PubMed Central

Background We have earlier shown that Bacille Calmette-Guérin (BCG) vaccine-specific IgG Antibodies in Lymphocyte Supernatant (ALS) can be used for diagnosis of active tuberculosis (TB) in adults and children. Methodology/Principal Findings The ALS method was validated in a larger cohort (n?=?212) of patients with suspicion of pulmonary TB using multiple antigens (BCG, LAM, TB15.3, TB51A, CFP10-ESAT6-A, CFP, CW) from Mycobacterium tuberculosis. The sensitivity and specificity of the ALS assay was calculated using non-TB patients as controls. The sensitivity and the specificity were highest with BCG vaccine (90% and 88% respectively) followed by LAM (89% and 87% respectively). Simultaneous assessment of multiple antigen-specific antibodies increased sensitivity (91%) and specificity (88%). Using higher lymphocyte count in smaller volume of culture media increased detection and reduced the assay duration to ?30 hrs. Twenty one patients with clinical findings strongly suggestive of TB finally diagnosed as non-TB patients were positive by the ALS assay, of which 9 (43%) were positive for 7 antigens and 19 (90%) for at least 3 antigens. Conclusions/Significance Our findings show that simultaneous detection of antigens improves the diagnostic potential of the ALS assay; the modified method increases sensitivity and can provide results in <48 hours, and enable detection of some cases of pulmonary TB that are not detectable by standard methods.

Rekha, Rokeya Sultana; Kamal, S. M. Mostafa; Andersen, Peter; Rahim, Zeaur; Hoq, Md. Imranul; Ara, Gul; Andersson, Jan; Sack, David; Raqib, Rubhana

2011-01-01

290

Bone marrow mononuclear cells protect neurons and modulate microglia in cell culture models of ischemic stroke.  

PubMed

Although several studies have provided evidence for the therapeutic potential of bone marrow-derived mononuclear cells (MNCs) in animal models of stroke, the mechanisms underlying their benefits remain largely unknown. We have determined the neuroprotective potential of MNCs in primary neuronal cultures exposed to various injuries in vitro. Cortical neurons in culture were exposed to oxygen-glucose deprivation, hypoxia, or hydrogen peroxide, and cell death was assayed by MTT, caspase-3 activation or TUNEL labelling at 24 hrs. Cultures were randomized to cotreatment with MNC-derived supernatants or media before injury exposure. In separate experiments, macrophage or microglial cultures were exposed to lipopolypolysacharide (LPS) in the presence and absence of MNC-derived supernatants. Neuronal cultures were then exposed to conditioned media derived from activated macrophages or microglia. Cytokines from the supernantants of MNC cultures exposed to normoxia or hypoxia were also estimated by enzyme-linked immunosorbant assay (ELISA). MNC-derived supernatants attenuated neuronal death induced by OGD, hypoxia, hydrogen peroxide, and conditioned macrophage/microglial media and contain a number of trophic factors, including interleukin-10, insulin-like growth factor-1, vascular endothelial growth factor, and stromal cell-derived factor-1. MNCs provide broad neuroprotection against a variety of injuries relevant to stroke. PMID:20629187

Sharma, Sushil; Yang, Bing; Strong, Roger; Xi, XiaoPei; Brenneman, Miranda; Grotta, James C; Aronowski, Jaroslaw; Savitz, Sean I

2010-10-01

291

Microtechnology for Stem Cell Culture  

Microsoft Academic Search

\\u000a Advances in stem cell research in recent decades have been aided by progress in the development of novel technologies aimed\\u000a at biological systems. At the same time mimicking stem cell niches in vitro has become crucial for both basic stem cell research\\u000a and the development of innovative therapies based on stem cells. Innovative microscale technologies can contribute to our\\u000a quantitative

Elena Serena; Elisa Cimetta; Camilla Luni; Nicola Elvassore

292

Quantitative Analysis of Cobblestone Area-Forming Cells in Bone Marrow of Patients With Aplastic Anemia by Limiting Dilution Assay  

Microsoft Academic Search

In the past, the analysis of primitive human hematopoietic progenitor cells with repopulating activity was limited by lack of appropriate in vitro assay systems. It was recently shown that cobblestone area-forming cells (CAFC) giving rise to cobblestone areas after 5 weeks in long-term marrow cultures (LTMC) represent a population of pluripotent pro- genitor cells with long-term marrow-repopulating activity. We have

Hubert Schrezenrneier; Marianne Jenal; Friedhelm Herrrnann; Herrnann Heirnpel; Aruna Raghavachar

1996-01-01

293

Increased mechanosensitivity of cells cultured on nanotopographies  

PubMed Central

Enhancing cellular mechanosensitivity is recognized as a novel tool for successful musculoskeletal tissue engineering. We examined the hypothesis that mechanosensitivity of human mesenchymal stem cells (hMSCs) is enhanced on nanotopographic substrates relative to flat surfaces. hMSCs were cultured on polymer-demixed, randomly distributed nanoisland surfaces with varying island heights and changes in intracellular calcium concentration, [Ca2+]i, in response to fluid flow induced shear stress were quantifide. Stem cells cultured on specific scale nanotopographies displayed greater intracellular calcium responses to fluid flow. hMSCs cultured on 10-20 nm high nanoislands displayed a greater percentage of cells responding in calcium relative to cells cultured on flat control, and showed greater average [Ca2+]i increase relative to cells cultured on other nanoislands (45-80 nm high nanoislands). As [Ca2+]i is an important regulator of downstream signaling, as well as proliferation and differentiation of hMSCs, this observation suggests that specific scale nanotopographies provide an optimal milieu for promoting stem cell mechanotransduction activity. That mechanical signals and substrate nanotopography may synergistically regulate cell behavior is of significant interest in the development of regenerative medicine protocols.

Salvi, Joshua D.; Lim, Jung Yul; Donahue, Henry J.

2012-01-01

294

IL-12 elispot assays to detect and enumerate IL-12 secreting cells.  

PubMed

The cytokine IL-12 promotes Th(1)type immune responses and plays a key role in immune regulation. The complex nature of IL-12 hampered its detection without use of stimulants that might give less relevant information. To detect circulating IL-12 p40, we developed enzyme-linked immunospot (ELISPOT) assays that allow enumeration of IL-12 p40 secreting cells without prior in vitro stimulation of the cells. In parallel, intracellular staining of IL-12 p40 by flow cytometry was performed to compare the two methods. IL-12 p40 secreting cells were detected in healthy subjects at a mean number of 103+/-155 per 10(5)blood mononuclear cells (MNC). Numbers of IL-12 p40 secreting blood MNC correlated with IL-12 p40 positive blood MNC detected by flow cytometry. Bacterial endotoxins and the inflammatory cytokines TNF-alpha and IFN-gamma control IL-12 production by antigen presenting cells. Utilizing IL-12 p40 ELISPOT assays, we could confirm occurrence of elevated numbers of IL-12 p40 secreting blood MNC after stimulation with TNF-alpha, IFN-gamma, LPS, LPS+TNF-alpha or LPS+IFN-gamma, compared to cultures without stimulant. Due to its central role in inflammation and autoimmunity, IL-12 is an attractive target for immunotherapy. IL-12 p40 ELISPOT assays represent a sensitive, specific and reliable tool for investigating the role of IL-12 in both health and disease. PMID:10930299

Ozenci, V; Kouwenhoven, M; Press, R; Link, H; Huang, Y M

2000-08-01

295

The effect of tricyclic antidepressants on cutaneous melanoma cell lines and primary cell cultures.  

PubMed

The tricyclic antidepressants have previously been shown to exert activity against glioma cells in vitro. Initial studies in cell lines suggested that this might extend to melanoma cells. We have therefore conducted a study in primary cell cultures from metastatic cutaneous melanoma deposits using a well established ATP-based tumour chemosensitivity assay to confirm and extend these findings. Two cell lines and eight primary cell cultures from metastatic melanoma deposits were exposed to three tricyclic drugs, amitriptyline, nortriptyline and clomipramine, at concentrations ranging from 200 to 6.25 µmol/l in the ATP-based tumour chemosensitivity assay. All three drugs showed activity, although nortriptyline was more active than clomipramine or amitriptyline in both cell lines and primary cell cultures, with an IC50 of 9, 27 and 33 µmol/l, respectively. Tricyclic agents show activity against melanoma in vitro. This could be related to the lysosomal effects based on their cationic amphiphilic properties, or effects at the mitochondrial membrane. PMID:21897201

Parker, Katharine A; Glaysher, Sharon; Hurren, Jeremy; Knight, Louise A; McCormick, Deidre; Suovouri, Anne; Amberger-Murphy, Verena; Pilkington, Geoffrey J; Cree, Ian A

2012-01-01

296

Transferring isolated mitochondria into tissue culture cells  

PubMed Central

We have developed a new method for introducing large numbers of isolated mitochondria into tissue culture cells. Direct microinjection of mitochondria into typical mammalian cells has been found to be impractical due to the large size of mitochondria relative to microinjection needles. To circumvent this problem, we inject isolated mitochondria through appropriately sized microinjection needles into rodent oocytes or single-cell embryos, which are much larger than tissue culture cells, and then withdraw a ‘mitocytoplast’ cell fragment containing the injected mitochondria using a modified holding needle. These mitocytoplasts are then fused to recipient cells through viral-mediated membrane fusion and the injected mitochondria are transferred into the cytoplasm of the tissue culture cell. Since mouse oocytes contain large numbers of mouse mitochondria that repopulate recipient mouse cells along with the injected mitochondria, we used either gerbil single-cell embryos or rat oocytes to package injected mouse mitochondria. We found that the gerbil mitochondrial DNA (mtDNA) is not maintained in recipient rho0 mouse cells and that rat mtDNA initially replicated but was soon completely replaced by the injected mouse mtDNA, and so with both procedures mouse cells homoplasmic for the mouse mtDNA in the injected mitochondria were obtained.

Yang, Yi-Wei; Koob, Michael D.

2012-01-01

297

Development in primary cell culture of demosponges  

Microsoft Academic Search

We have established primary cell culture of the marine demosponge Dysidea avara and Suberites domuncula. Microbial contamination was controlled by the use of a pool of antibiotics confirming the goodness of this procedure. Effect of pH, temperature and light was studied to establish the better growth conditions. The comparison of lipid composition of sponge and cells suggested a series of

Salvatore De Rosa; Salvatore De Caro; Carmine Iodice; Giuseppina Tommonaro; Kamen Stefanov; Simeon Popov

2003-01-01

298

[Cell culture of human gingival epithelium].  

PubMed

Gingival explants were taken from 8 volunteers in order to find a method to grow gingival epithelial cells. We succeeded in what we regarded as optimal conditions in achieving a monolayer cell thickness in the culture by means of BHK medium and foetal calf serum. PMID:271582

Heidemann, D; Lampert, F

1978-01-01

299

Stamp wound assay for studying coupled cell migration and cell debris clearance.  

PubMed

A new method for studying wound healing under realistic conditions in vitro was developed. The method involves creating defined patterns of damaged cell debris with poly(dimethyl)siloxane (PDMS) stamping. This novel assay permitted the quantification of wound healing rates in the presence of cell debris. Experimental results with this assay suggest that cell migration in the presence of cell debris is a two step process requiring (1) non-muscle myosin II-dependent cell clearance followed by (2) cell migration into newly cleared wound areas. The novel stamp wound assay allows the study of coupled cell migration and debris clearance and is a more realistic wound healing assay in vitro. PMID:20961056

Lee, Jiyeon; Wang, Yu-Lin; Ren, Fan; Lele, Tanmay P

2010-10-20

300

Influence of three laser wavelengths on human fibroblasts cell culture.  

PubMed

Although experimental studies in vitro and vivo have been numerous, the effect of laser wavelength irradiation on human fibroblast cell culture is poorly understood. This emphasizes the need of additional cellular and molecular research into laser influence with low energy and power. The aim of this study was to assess the influence of three different laser wavelengths on the human skin fibroblasts cell culture. We wanted to evaluate if near infrared lasers had any influence in healing of wounds by stimulating mitochondrial activity of fibroblasts. The cells were irradiated using 830-, 980- and 2,940-nm laser wavelengths. The irradiated cells were incubated and their mitochondrial activity was assessed by the MTT assay at 24, 48 and 72 h. Simultaneously, an apoptosis assay was assessed on the irradiated fibroblasts. It can be concluded that laser light of the near-infrared region (830 and 980 nm) influences fibroblasts mitochondrial activity compared to the 2,940-nm wavelength which produces apoptosis. PMID:22447404

Crisan, Bogdan; Soritau, Olga; Baciut, Mihaela; Campian, Radu; Crisan, Liana; Baciut, Grigore

2012-03-25

301

Optically micropatterned culture of adherent cells  

NASA Astrophysics Data System (ADS)

We used a liquid-crystal spatial light modulator to project 473 nm light patterns surrounding a region of adherent cells and achieved an arbitrarily micropatterned cell culture. For a group of ~60 cells, the cell boundaries fit the pattern of light within 15% deviation of the side length. We also demonstrated a wound-healing experiment with a definite starting temporal point by using this technique. While observing mitochondrial structures in the illuminated cells, we found that the 473 nm light damaged the integrity of mitochondria and thus prohibited cell proliferation in the illuminated region.

Xiao, Jian-Long; Pan, Huei-Jyuan; Lee, Chau-Hwang

2012-07-01

302

Adaptation of a sandwich enzyme-linked immunosorbent assay to determine the concentration of bovine leukemia virus p24 and optimal conditions for p24 expression in short-term cultures of peripheral blood mononuclear cells  

Microsoft Academic Search

Bovine leukemia virus (BLV) is a common retroviral infection of cattle. Infection is accompanied by integration of BLV into the host cell genome and is persistent for the life of the individual as is the presence of anti-BLV antibodies. Lymphosarcoma occurs in a small fraction of infected adult individuals but otherwise there is little or no associated disease. Viremia is

M. van den Heuvel; D. Portetelle; B. Jefferson; R. M. Jacobs

2003-01-01

303

Marine invertebrate cell cultures: new millennium trends.  

PubMed

This review analyzes activities in the field of marine invertebrate cell culture during the years 1999 to 2004 and compares the outcomes with those of the preceding decade (1988 to 1998). During the last 5 years, 90 reports of primary cell culture studies of marine organisms belonging to only 6 taxa (Porifera, Cnidaria, Crustacea, Mollusca, Echinodermata, and Urochordata) have been published. This figure represents a 2-fold increase in the annual number of publications over the decade 1988 to 1998. Three other trends distinguish the two reviewed periods. First, in recent years studies attempting to improve cell culture methodologies have decreased, while interest in applications of already existing methodologies has increased. This reflects the effects of short-term cultures in attracting new researchers and scientific disciplines to the field. Second, only 17.8% of the recent publications used long-term cultures, compared with 30.0% of the publications in the previous decade. Third, during recent years research in cell cultures has studied fewer model species more extensively (mainly, Botryllus schlosseri, Crassostrea, Mytilus, Penaeus, and Suberites domuncula), signifying a shift from previous investigations that had studied a more diverse range of organisms. From 1988 to 1998 the phylum Mollusca was the most studied taxon (34.4%), but recent years have seen more studies of Porifera and Crustacea (30.0% and 32.2% of publications) than of Mollusca (21.1%). Still, not even a single established cell line from any marine invertebrate has yet been made available. However, the use of new cellular, genomic, and proteomic tools may fundamentally change our strategy for the development of cell cultures from marine invertebrates. PMID:16132466

Rinkevich, Baruch

2005-08-24

304

Genotoxicity of complex mixtures: CHO cell mutagenicity assay  

SciTech Connect

A Chinese hamster ovary (CHO) mammalian cell assay was used to evaluate the genotoxicity of complex mixtures (synthetic fuels). The genotoxicity (mutagenic potency) of the mixtures increased as the temperature of their boiling range increased. Most of the genotoxicity in the 750/sup 0/F+ boiling-range materials was associated with the neutral polycyclic aromatic hydrocarbon (PAH) fractions. Chemical analysis data indicate that the PAH fractions of high-boiling coal liquids contain a number of known chemical carcinogens, including five- and six-ring polyaromatics (e.g., benzo(a)pyrene) as well as four- and five-ring alkyl-substituted PAH (e.g., methylchrysene and dimethylbenzanthracenes); concentrations are a function of boiling point (bp). In vitro genotoxicity was also detected in fractions of nitrogen-containing polyaromatic compounds, as well as in those with aliphatics of hydroxy-containing PAH. Mutagenic activity of some fractions was detectable in the CHO assay in the absence of an exogenous metabolic activation system; in some instances, addition of exogenous enzymes and cofactors inhibited expression of the direct-acting mutagenic potential of the fraction. These data indicate that the organic matrix of the chemical fraction determines whether, and to what degree, various mutagens are expressed in the CHO assay. Therefore, the results of biological assays of these mixtures must be correlated with chemical analyses for proper interpretation of these data. 29 references, 16 figures, 4 tables.

Frazier, M.E.; Samuel, J.E.

1985-02-01

305

The consensus mechanics of cultured mammalian cells  

PubMed Central

Although understanding cells' responses to mechanical stimuli is seen as increasingly important for understanding cell biology, how to best measure, interpret, and model cells' mechanical properties remains unclear. We determine the frequency-dependent shear modulus of cultured mammalian cells by using four different methods, both unique and well established. This approach clarifies the effects of cytoskeletal heterogeneity, ATP-dependent processes, and cell regional variations on the interpretation of such measurements. Our results clearly indicate two qualitatively similar, but distinct, mechanical responses, corresponding to the cortical and intracellular networks, each having an unusual, weak power-law form at low frequency. The two frequency-dependent responses we observe are remarkably similar to those reported for a variety of cultured mammalian cells measured with different techniques, suggesting it is a useful consensus description. Finally, we discuss possible physical explanations for the observed mechanical response.

Hoffman, Brenton D.; Massiera, Gladys; Van Citters, Kathleen M.; Crocker, John C.

2006-01-01

306

Isolation and culture of mouse intestinal cells.  

PubMed

Complex cell signal transduction mechanisms regulate intestinal epithelial shape, polarity, motility, organelles, cell membrane components as well as physical and mechanical properties to influence alimentary digestion, absorption, secretion, detoxification and fluid balance. Interactions between the epithelial cells and adjacent mesenchyme are central to intestinal homeostasis although the key regulatory molecules of specific differentiation steps remain unclear. Isolation and primary culture of heterotypic murine intestinal cells provides a model system for elucidation of essential molecular cross-talk between epithelium and mesenchyme that may provide several biological and practical advantages over transformed cell lines. An in vitro primary culture system for neonatal rat or mouse intestinal cells has been established that forms monolayers, expresses intestine-specific epithelial features including intestinal brush borders and appropriate hydrolase enzymes. Our studies confirm the promise of this method which may advance our understanding of heterotypic cellular interactions implicated in intestinal function and may provide important insights into the pathobiology of disease. PMID:20204629

Campbell, Charles Frederick

2010-01-01

307

Studies of ?-protein in human cell cultures  

Microsoft Academic Search

Summary  ?-Protein growth fraction (AGF) eliminates the 60- to 90-day adaptive phase required to establish actively growing cultures\\u000a of HeLa (Gey), human heart (Girardi), KB (Eagle) and other established cell lines in serum-free chemically defined medium\\u000a A3. AGF is effective at less than 0.4 ?g per ml. By using the procedures described in the text, it is possiblee to culture HeLa

Richard Holmes; Gretchen Mercer; Nalini Mohamed

1979-01-01

308

Cell Culture Imaging Using Microimpedance Tomography  

Microsoft Academic Search

We present a novel, inexpensive, and fast microimpedance tomography system for two-dimensional imaging of cell and tissue cultures. The system is based on four-electrode measurements using 16 planar microelectrodes (5 mum x 4 mm) integrated into a culture chamber. An Agilent 4294A impedance analyzer combined with a front-end amplifier is used for the impedance measurements. Two-dimensional images are obtained using

Pontus Linderholm; Laurent Marescot; Meng Heng Loke; Philippe Renaud

2008-01-01

309

Canine coronavirus induces apoptosis in cultured cells  

Microsoft Academic Search

Canine coronavirus (CCoV) is widespread in dogs in several countries and causes mild enteric illness evolving to severe enteritis in young pups.In in vitro cultures canine coronaviruses generally induce extensive cell death, however nature of the events leading to cell death remains largely unknown.We analysed the induction of cytopathic effect by CCoV in a canine fibrosarcoma cell line (A-72) in

A. Ruggieri; L. Di Trani; I. Gatto; M. Franco; E. Vignolo; B. Bedini; G. Elia; C. Buonavoglia

2007-01-01

310

A serum-free primary culture system for studying cell-substrate interactions during newt epidermal cell migration  

Microsoft Academic Search

Summary  To study the interaction of migrating newt epidermal cells with purified extracellular matrix (ECM) molecules we have developed\\u000a an in vitro migration assay using pieces of newt skin explanted onto culture dishes coated with various ECM molecules and\\u000a cultured for 18 h in defined serum-free medium. Newt epidermal cells migrate out from explants placed on dishes coated with\\u000a either collagen,

James T. Mahan; Donald J. Donaldson

1988-01-01

311

Henrietta Lacks, HeLa cells, and cell culture contamination.  

PubMed

Henrietta Lacks died in 1951 of an aggressive adenocarcinoma of the cervix. A tissue biopsy obtained for diagnostic evaluation yielded additional tissue for Dr George O. Gey's tissue culture laboratory at Johns Hopkins (Baltimore, Maryland). The cancer cells, now called HeLa cells, grew rapidly in cell culture and became the first human cell line. HeLa cells were used by researchers around the world. However, 20 years after Henrietta Lacks' death, mounting evidence suggested that HeLa cells contaminated and overgrew other cell lines. Cultures, supposedly of tissues such as breast cancer or mouse, proved to be HeLa cells. We describe the history behind the development of HeLa cells, including the first published description of Ms Lacks' autopsy, and the cell culture contamination that resulted. The debate over cell culture contamination began in the 1970s and was not harmonious. Ultimately, the problem was not resolved and it continues today. Finally, we discuss the philosophical implications of the immortal HeLa cell line. PMID:19722756

Lucey, Brendan P; Nelson-Rees, Walter A; Hutchins, Grover M

2009-09-01

312

Tumor necrosis factor-alpha (TNF-alpha) concentrations from whole blood cultures correlate with isolated peripheral blood mononuclear cell cultures  

Technology Transfer Automated Retrieval System (TEKTRAN)

Many cellular immune assays are impractical because they require labor-intensive isolation of cells from their natural environment. The objectives of this study were to determine the relationship between cell culture supernatant TNF-alpha from isolated peripheral blood mononuclear cells (PBMC) and w...

313

Towards tailored assays for cell-based approaches to toxicity testing.  

PubMed

The call for a new toxicology is mainly a call for cellular approaches and their computational integration. This article reflects on cell models, which are necessary to facilitate the transition. A mechanistic perspective has prompted the characterization of toxicity pathways and toxicity networks in order to develop robust cell-based assays for toxicity testing. Differing use scenarios for cell systems require higher degrees of sophistication, e.g., human-on-a-chip approaches are based on complex organotypic cultures to approximate the repertoire of human physiological reactions and high-throughput tests require simplicity and robustness. The new paradigm emerging under the branding of Toxicology for the 21(st) Century needs complex models for pathway of toxicity identification and simpler assays for testing the perturbation of any given pathway. With increasing knowledge about underlying mechanisms, the needs for complexity and test specificity will change. Selective cell-based assays are desirable, especially for the detection of novel toxicants and biothreats. Examples from endocrine disruption, pyrogenicity, and especially shellfish toxin testing are used to illustrate such developments. PMID:23138507

Rossini, Gian Paolo; Hartung, Thomas

2012-01-01

314

Photomicronucleus assay of phototoxic and pseudophotoclastogenic chemicals in human keratinocyte NCTC2544 cells.  

PubMed

Photochemical genotoxicity was evaluated in human keratinocyte NCTC2544 cells. The cells were pre-treated with photogenotoxic or pseudophotoclastogenic chemicals and irradiated with a solar-simulator for 50min at a total UV dose of 5J/cm(2) or placed in the dark for the same period. After washing, the cells were cultured for 1.5-2 cell cycles with fresh culture medium. At the end of culturing, slide specimens were prepared and examined for micronucleus formation. 8-Methoxypsoralen, a photogenotoxic chemical, strongly induced micronucleated cells with UV irradiation but not under non-irradiation conditions. Therefore, NCTC2544 cells were subjected to further investigation to evaluate the possible photogenotoxicity of other chemicals. 6-Methylcoumarin, 3,3',4',5-tetrachlorosalicylanilide and protoporphyrin IX disodium salt, which are all known phototoxic substances, induced micronucleated cells with irradiation but not in the non-irradiation state. These phototoxic substances were confirmed to be photogenotoxic. Tetrabenzoporphine and 5-aminolevulinic acid, which are used for photodynamic therapy, showed phototoxicity. However, these chemicals did not induce micronucleated cells in the irradiated or non-irradiated state, suggesting a lack of photogenotoxicity. Among 3 pseudophotoclastogenic chemicals having no light absorbance at 290-700nm, neither cycloheximide nor disulfoton induced micronucleated cells with or without irradiation; zinc oxide induced micronucleated cells with irradiation and, to a lesser extent, without irradiation. Based on the results of the photogenotoxicity assays of these 9 chemicals, NCTC2544 cells are considered to be a suitable test system to evaluate the photogenotoxic potential of chemicals. PMID:21524715

Horinouchi, Mayumi; Arimoto-Kobayashi, Sakae

2011-04-15

315

Abeta Mediated Diminution of MTT Reduction---An Artefact of Single Cell Culture?  

Microsoft Academic Search

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT) reduction assay is a frequently used and easily reproducible method to measure beta-amyloid (A?) toxicity in different types of single cell culture. To our knowledge, the influence of A? on MTT reduction has never been tested in more complex tissue. Initially, we reproduced the disturbed MTT reduction in neuron and astroglia primary cell cultures from rats as

Raik Rönicke; Anja Klemm; Jessica Meinhardt; Ulrich H. Schröder; Marcus Fändrich; Klaus G. Reymann; Hilal Lashuel

2008-01-01

316

Effects of abscisic acid on the secondary metabolism of cultured Onosma paniculatum cells  

Microsoft Academic Search

ABA addition to B5 or M9 medium at the concentrations from 0.1 to 5.0 mg\\/l suppressed growth of Onosma paniculatum cells. The addition of these ABA concentrations to M9 medium also significantly decreased the formation of shikonin and its\\u000a derivatives in the cultured cells during the entire course of culturing. The enzyme activity assay showed that, on the 4th\\u000a day

D.-Y. Sun; Z.-J. Yin; Sh.-J. Wu; J. Su; Sh. Shi; H. Wu; F.-H. Xiao; J.-L. Qi; Zh. Liu; Y.-J. Pang; H.-G. Shen; Y.-H. Yang

2007-01-01

317

A simple immunoperoxidase method for detecting enteric adenovirus and rotavirus in cell culture.  

PubMed

A technique which includes the use of indirect immunoperoxidase antibody (IPA) has been developed for detecting enteric adenovirus and rotavirus antigens in cell cultures and has been compared with immunofluorescence antibody assay (IFA). The IPA technique was as sensitive as the IFA. The number of positive cells detected by both techniques in tissue cultures was the same; false positive results were not observed. The applicability of IPA in clinical virology is discussed. PMID:6321601

Cevenini, R; Rumpianesi, F; Mazzaracchio, R; Donati, M; Falcieri, E; Sarov, I

1984-01-01

318

A new culturing strategy optimises Drosophila primary cell cultures for structural and functional analyses  

Microsoft Academic Search

Neurons in primary cell cultures provide important experimental possibilities complementing or substituting those in the nervous system. However, Drosophila primary cell cultures have unfortunate limitations: they lack either a range of naturally occurring cell types, or of mature physiological properties. Here, we demonstrate a strategy which supports both aspects integrated in one culture: Initial culturing in conventional serum-supplemented Schneider's medium

Barbara Küppers-Munther; Johannes J. Letzkus; Karin Lüer; Gerhard Technau; Hartmut Schmidt; Andreas Prokop

2004-01-01

319

Biosynthesis of cellulose: studies with tobacco protoplasts and cultured cells  

SciTech Connect

The cell wall of regenerating tobacco protoplasts was shown to be mainly composed of noncellulosic ..beta..-1,3- and ..beta..-1,4-linked glucans with a cellulose content of only about 5%. Some pectic and hemicellulosic material is released by these protoplasts into the culture medium. The DP distribution of the ..cap alpha..-cellulose in regenerating protoplasts as well as in suspension-cultured cells, callus, or tobacco mesophyll revealed the existence of mainly two DP fractions with low (DP<500) and higher (DP 2000-3000) molecular weight, both of which contribute to the cellulosic network of the primary cell wall. The alkali-soluble and alkali-insoluble products of glucan synthetase assays with particulate enzyme fractions were analyzed in detail. By prelabeling with (/sup 14/C)glucose, the existence of primer glucans, which are elongated in the appropriate in vitro assay, could be substantiated. Alkali-soluble glucans consisted of a very short, if any, primer glucan, to which about 40 glucose units were added in vitro. The glucans in the alkali-insoluble fraction have an average DP of 200-250 and are synthesized in vitro by chain elongation via addition of about 30 new glucose units to a 1,4-linked primer glucan of DPapprox.200. 27 references, 6 figures, 2 tables.

Franz, G.; Blaschek, W.; Haass, D.; Koehler, H.

1983-01-01

320

Effect of plasma needle on cultured cells  

NASA Astrophysics Data System (ADS)

To investigate a possible application of plasma in fine surgery, we studied the effects of a small atmospheric glow discharge on living cultured cells. The plasma source used for this purpose was the "plasma needle". Plasma needle is a small (below 1mm) non-thermal radio-frequency glow, operating in helium mixtures with air at ambient pressure. Plasma treatment of cultured cells resulted in detachment of the cells. Viability tests using propidium iodide staining in combination with confocal laser scanning microscopy confirmed that detached cells as well as surrounding cells remained alive. When the cells received a low dose of plasma treatment, they reattached within a few hours to the surface of the culture flask and to each other. Removal of cells with high precision, without damage to adjacent cells, promises to become a new surgical technique. For investigation of the mechanism causing this detachment we investigated the gas mixture of the plasma with Raman scattering measurements. Radicals diffusing from the plasma into a liquid were detected by means of fluorescent probe in combination with laser-induced fluorescence spectroscopy.

Kieft, I. E.; Dvinskikh, N. A.; Broers, Jos L. V.; Slaaf, Dick W.; Stoffels, Eva

2004-05-01

321

Evaluation of drug toxicity with hepatocytes cultured in a micro-space cell culture system  

Microsoft Academic Search

A micro-space cell culture system was recently developed in which cells such as hepatocytes can be cultured and formed into a multicellular three-dimensional (3D) architecture. In this study, we assessed the performance of HepG2 cells cultured in this micro-space cell culture system in a drug toxicity test, and evaluated the effects of micro-space culture on their hepatocyte-specific functions. The micro-space

Kazuaki Nakamura; Reiko Mizutani; Atsushi Sanbe; Shin Enosawa; Mureo Kasahara; Atsuko Nakagawa; Yoko Ejiri; Norie Murayama; Yuki Miyamoto; Tomohiro Torii; Shinji Kusakawa; Junji Yamauchi; Motohiro Fukuda; Hiroshi Yamazaki; Akito Tanoue

2011-01-01

322

Three-dimensional cultures of mouse mammary epithelial cells.  

PubMed

The mammary gland is an ideal "model organism" for studying tissue specificity and gene expression in mammals: it is one of the few organs that develop after birth and it undergoes multiple cycles of growth, differentiation and regression during the animal's lifetime in preparation for the important function of lactation. The basic "functional differentiation" unit in the gland is the mammary acinus made up of a layer of polarized epithelial cells specialized for milk production surrounded by myoepithelial contractile cells, and the two-layered structure is surrounded by basement membrane. Much knowledge about the regulation of mammary gland development has been acquired from studying the physiology of the gland and of lactation in rodents. Culture studies, however, were hampered by the inability to maintain functional differentiation on conventional tissue culture plastic. We now know that the microenvironment, including the extracellular matrix and tissue architecture, plays a crucial role in directing functional differentiation of organs. Thus, in order for culture systems to be effective experimental models, they need to recapitulate the basic unit of differentiated function in the tissue or organ and to maintain its three-dimensional (3D) structure. Mouse mammary culture models evolved from basic monolayers of cells to an array of complex 3D systems that observe the importance of the microenvironment in dictating proper tissue function and structure. In this chapter, we focus on how 3D mouse mammary epithelial cultures have enabled investigators to gain a better understanding of the organization, development and function of the acinus, and to identify key molecular, structural, and mechanical cues important for maintaining mammary function and architecture. The accompanying chapter of Vidi et al. describes 3D models developed for human cells. Here, we describe how mouse primary epithelial cells and cell lines--essentially those we use in our laboratory--are cultured in relevant 3D microenvironments. We focus on the design of functional assays that enable us to understand the intricate signaling events underlying mammary gland biology, and address the advantages and limitations of the different culture settings. Finally we also discuss how advances in bioengineering tools may help towards the ultimate goal of building tissues and organs in culture for basic research and clinical studies. PMID:23097110

Mroue, Rana; Bissell, Mina J

2013-01-01

323

Discriminating Different Cancer Cells Using a Zebrafish in Vivo Assay  

PubMed Central

Despite the expanded understanding of tumor angiogenesis phenomenon and how it impacts cancer treatment outcomes, we have yet to develop a robust assay that can quickly, easily, and quantitatively measure tumor-induced angiogenesis. Since the zebrafish/tumor xenograft represents an emerging tool in this regard, the present study strives to capitalize on the ease, effectiveness, and the adaptability of this model to quantify tumor angiogenesis. In order to test a range of responses, we chose two different tumorigenic cell lines, the human non-small cell lung carcinoma (H1299) and the mouse lung adenocarcinoma (CL13). Non-tumorigenic 3T3-L1 cells served as negative control. The cells were grafted near to the perivitelline space of the zebrafish embryos and the angiogenic response was analyzed using whole-mount alkaline phosphatase (AP) vessel staining and fluorescence microscopy. Angiogenic activity was scored based on the length and number of the newly formed ectopic vessels and the percentage of embryos with ectopic vessels. At 2 day-post-implantation, we detected a significant increase in the length and number of ectopic vessels with H1299 cell implantation compared to CL13 cell transplantation, both are higher than 3T3-L1 control. We also observed a significantly higher percentage of embryos with ectopic vessels with H1299 and CL13 transplantation compared to the 3T3-L1 control, but this parameter is not as robust and reliable as measuring the length and number of ectopic vessels. Furthermore, the systemic exposure of zebrafish embryos to an anti-angiogenesis drug (PTK 787, inhibitor of vascular endothelial growth factor receptor tyrosine kinase) inhibited tumor-induced angiogenesis, suggesting that the assay can be used to evaluate anti-angiogenic drugs. This study implicates the feasibility of using zebrafish xenotransplantation to perform quantitative measurement of the angiogenic activity of cancer cells which can be further extended to measure cancer cell metastasis. This assay represents not only the useful test for patient diagnosis, but also has the potential for evaluating anti-cancer drugs treatment.

Moshal, Karni S.; Ferri-Lagneau, Karine F.; Haider, Jamil; Pardhanani, Pooja; Leung, TinChung

2011-01-01

324

An enzyme-linked immunosorbent assay for estrogenicity using primary hepatocyte cultures from the channel catfish (Ictalurus punctatus).  

PubMed

An in vitro assay has been developed to screen for estrogenic activity of single chemicals or complex mixtures. This method combines primary hepatocyte cultures from the channel catfish (Ictalurus punctatus) with an enzyme-linked immunosorbant assay (ELISA) to detect and quantify the production of vitellogenin (VTG), a liver-derived, estrogen-induced lipoprotein. A variety of environmentally relevant chemicals and chemical mixtures were tested, including the polyaromatic hydrocarbon benzo(a)pyrene (BaP), the alkylphenolic surfactants 4-tert-octylphenol (OP) and p-nonylphenol (NP), the chlorinated insecticide o,p'-DDT, the plant derivative stigmastanol, and a number of waste waters from pulp and paper mills. In addition, the effects of estradiol (E2), the synthetic estrogen diethylstilbestrol (DES) and the antiestrogens trans-1-(4-beta-dimethylamino-ethoxyphenyl)-1,2-diphenylbut-1-ene (tamoxifen) and 7alpha-[9-(4,4,5,5, 5-pentafluoro-pentylsulfinyl)nonyl]estra-3,17beta-diol (ICI-182,780) were also examined. The following compounds were observed to be estrogenic: DES > E2 > OP > o,p'-DDT > NP. Tests with BaP, stigmastanol, tamoxifen, ICI-182,780, and four paper mill effluents exhibited no detectable estrogenic activity. Furthermore, both tamoxifen and ICI-182,780 significantly reduced VTG synthesis by cells incubated with E2 or DES. Stigmastanol and the mill effluents were also tested for anti-estrogenic activity in cells incubated in media containing both DES and stigmastanol or effluent. Compared to DES alone, none of these treatments caused a significant reduction in the media concentrations of VTG. The detection limit for this assay was typically 15-25 ng VTG/ml medium. Screening results and performance characteristics such as inter- and intra-assay variability were similar to those reported for VTG assays for other teleost species. Thus, the present work provides a sensitive, rapid means for screening the estrogenic potency of environmentally relevant chemicals and chemical mixtures in vitro. PMID:10341043

Monteverdi, G H; Di Giulio, R T

1999-07-01

325

Photoreceptor-like cells from reprogramming cultured mammalian RPE cells  

PubMed Central

Purpose Previous studies showed that chick retinal pigment epithelium (RPE) cells can be reprogrammed by a specific gene to take on the path of photoreceptor differentiation. In this study, we tested whether this reprogramming scheme could be applied to mammalian RPE cells. Methods Human RPE cell lines ARPE-19, a spontaneously transformed line of RPE cells derived from a 19-year-old person, and hTERT-RPE1, a telomerase-immortalized RPE cell line derived from a 1-year-old person, were commercially obtained and cultured as recommended. Primary RPE cell cultures were established using RPE isolated from 3- to 6-month-old pig and postnatal day 5 mouse. Cultured cells were transduced with a virus expressing neuroD, neurogenin1 (ngn1), or ngn3, basic helix-loop-helix (bHLH) genes previously identified as capable of inducing RPE-to-photoreceptor reprogramming in the chick system. Alternatively, cells in the culture were transfected chemically or physically through electroporation with vector DNA expressing one of the three genes. The cultures were then analyzed for RPE-to-photoreceptor reprogramming with in situ hybridization and/or immunostaining for photoreceptor gene expression. Results Both hTERT-RPE1 and ARPE-19 cultures gave rise to cells bearing markers of photoreceptors after transduction or transfection with vehicles expressing neuroD or ngn1. The new cells expressed genes encoding photoreceptor proteins, including interphotoreceptor retinoid-binding protein IRBP), recoverin, retinal cone arrestin 3, transducin ?-subunit, Cone-rod homeobox protein (Crx), and red opsin. They displayed morphologies resembling differentiating photoreceptor cells. In primary porcine and mouse RPE cell cultures, transduction with lenti virus (Lvx-IRES-ZsGreen1) expressing ngn1 or ngn3 resulted in the emergence of ZsGreen1+ cells that exhibited morphologies reminiscent of differentiating photoreceptor cells. Immunochemistry showed that some ZsGreen1+ cells were positive for neural marker microtubule-associated protein 2 (Map2) and photoreceptor hallmark proteins red opsin and rhodopsin. Conclusions The results suggest that cells in human RPE cell lines and in primary cultures of porcine and mouse RPE respond to gene-induced reprogramming by giving rise to photoreceptor-like cells. The responsiveness of primary RPE cells, especially those from porcine cells, enhances the biologic feasibility of exploring RPE-to-photoreceptor reprogramming for in situ mammalian photoreceptor replacement without cell transplantation.

Yan, Run-Tao; Huang, Jian; Guidry, Clyde; Wang, Shu-Zhen

2013-01-01

326

Assaying stem cell mechanobiology on microfabricated elastomeric substrates with geometrically modulated rigidity.  

PubMed

We describe the use of a microfabricated cell culture substrate, consisting of a uniform array of closely spaced, vertical, elastomeric microposts, to study the effects of substrate rigidity on cell function. Elastomeric micropost substrates are micromolded from silicon masters comprised of microposts of different heights to yield substrates of different rigidities. The tips of the elastomeric microposts are functionalized with extracellular matrix through microcontact printing to promote cell adhesion. These substrates, therefore, present the same topographical cues to adherent cells while varying substrate rigidity only through manipulation of micropost height. This protocol describes how to fabricate the silicon micropost array masters (~2 weeks to complete) and elastomeric substrates (3 d), as well as how to perform cell culture experiments (1-14 d), immunofluorescence imaging (2 d), traction force analysis (2 d) and stem cell differentiation assays (1 d) on these substrates in order to examine the effect of substrate rigidity on stem cell morphology, traction force generation, focal adhesion organization and differentiation. PMID:21293460

Yang, Michael T; Fu, Jianping; Wang, Yang-Kao; Desai, Ravi A; Chen, Christopher S

2011-01-27

327

A rapid and robust assay for detection of S-phase cell cycle progression in plant cells and tissues by using ethynyl deoxyuridine  

PubMed Central

Background Progress in plant cell cycle research is highly dependent on reliable methods for detection of cells replicating DNA. Frequency of S-phase cells (cells in DNA synthesis phase) is a basic parameter in studies on the control of cell division cycle and the developmental events of plant cells. Here we extend the microscopy and flow cytometry applications of the recently developed EdU (5-ethynyl-2'-deoxyuridine)-based S-phase assay to various plant species and tissues. We demonstrate that the presented protocols insure the improved preservation of cell and tissue structure and allow significant reduction in assay duration. In comparison with the frequently used detection of bromodeoxyuridine (BrdU) and tritiated-thymidine incorporation, this new methodology offers several advantages as we discuss here. Results Applications of EdU-based S-phase assay in microscopy and flow cytometry are presented by using cultured cells of alfalfa, Arabidopsis, grape, maize, rice and tobacco. We present the advantages of EdU assay as compared to BrdU-based replication assay and demonstrate that EdU assay -which does not require plant cell wall digestion or DNA denaturation steps, offers reduced assay duration and better preservation of cellular, nuclear and chromosomal morphologies. We have also shown that fast and efficient EdU assay can also be an efficient tool for dual parameter flow cytometry analysis and for quantitative assessment of replication in thick root samples of rice. Conclusions In plant cell cycle studies, EdU-based S-phase detection offers a superior alternative to the existing S-phase assays. EdU method is reliable, versatile, fast, simple and non-radioactive and it can be readily applied to many different plant systems.

2010-01-01

328

Isolated identified Aplysia neurons in cell culture.  

PubMed

Methods have been developed for primary culture of large identified Aplysia neurons. Aplysia ganglia were treated with neutral protease to soften the connective tissue sheath. Individual neurons were isolated either by manipulation with tungsten needles or by tying off their axons with fine nylon filament and were immobilized in a chick plasma clot or a solution of methylcellulose. Somata up to approximately 300 micrometers in diameter extended long processes within several hours in culture. A single neuron produced as many as 10 processes which could grow at different rates. Intracellular recordings showed spontaneous and evoked action potentials in neurons cultured for up to 6 weeks. Electrical synapses formed between pairs of neurons in culture. In several culture dishes containing neurons from buccal ganglia, electrical coupling was observed between 90% of the cell pairs tested. This primary culture system currently is being used to compare the electrical and biochemical properties of neuronal processes with those of cell bodies and to study the conditions necessary for process regeneration and synapse formation between isolated identified neurons. PMID:7346582

Dagan, D; Levitan, I B

1981-07-01

329

Transplanted Long-Term Cultured Pre-BI Cells Expressing Calpastatin Are Resistant to B Cell Receptor-induced Apoptosis  

Microsoft Academic Search

Long-term cultured pre-B cells are able to differentiate into immunoglobulin (Ig)M-positive B cells (IgMcells) when transplanted into severe combined immunodeficient (SCID) mice. Based on previous studies, here we report the development of a reconstitution assay in non- obese diabetic\\/SCID (NOD\\/SCID) mice using pre-B cells, which allows us to study the role of calpains (calcium-activated endopeptidases) during B cell development as

Antonio Ruiz-Vela; Fernando Serrano; Manuel A. González; José Luis Abad; Antonio Bernad; Masatoshi Maki; Carlos Martínez-A

330

Glial cell growth in culture: Influence of living cell substrata  

Microsoft Academic Search

The role of the microenvironment in the growth of glial cells in culture has been the topic of ongoing research in this laboratory. Recently, we reported a study on the contribution of fibroblast cell substratum and extracellular matrix in glial cell growth. In the present study we report data concerning a) the influence of a neuronal-enriched living substratum from chick

N. Sakellaridis; D. Mangoura; A. Vernadakis

1984-01-01

331

Efficacy of ginkgolic acids against Cryptosporidium andersoni in cell culture.  

PubMed

Cryptosporidium is a worldwide waterborne parasite and the treatment is a severe problem in immunocompromised patients. In this study, we used the in vitro culture system to evaluate the anti-Cryptosporidium activity of ginkgolic acids (GAs), nitazoxanide (NTZ), garlicin (GAR), and artemether (ART). The growth of Cryptosporidium andersoni in HCT-8 cells was determined by real-time PCR assay. When exposed to 5.00 ?g/ml GAs or 10.00 ?g/ml NTZ for 48 h, the number of C. andersoni in cultures was on a very low lever, but the number of parasites did not significantly decrease when exposed to GAR and ART. Our results indicate that GAs could be a potential drug for the treatment of cryptosporidiosis. PMID:21556686

Wu, Liang; Jiang, Xu-gan; Shen, Yu-juan; Lu, Zhao-xi; Tu, Guo-hua; Fu, Xing-li; Chen, Sheng-xia; Cao, Jian-ping

2011-05-10

332

Growth of Plant Cell Cultures. Iii. Growth Kinetics and Mass Culture.  

National Technical Information Service (NTIS)

Suspension cultures of bean and lettuce cells have been maintained by serial transfer for over three years. Such cultures may show exponential growth, although growth rates are low with doubling times of three to four days. These suspension cultures have ...

M. Mandels R. O. Matthern H. M. El-Bisi

1968-01-01

333

Genotoxicity studies of methyl isocyanate in Salmonella, Drosophila, and cultured Chinese hamster ovary cells  

SciTech Connect

The genotoxic effects of methyl isocyanate (MIC) were investigated using four short-term tests: the Salmonella reversion assay (Ames test), the Drosophila sex-linked recessive lethal assay, and the sister chromatic exchange (SCE) and chromosomal aberration assays in cultured Chinese hamster ovary (CHO) cells. No evidence was found for the induction of mutations in either Salmonella or Drosophila. MIC did, however, induce SCEs and chromosomal aberrations in CHO cells both in the presence and absence of Aroclor-induced rat liver S-9.

Mason, J.M.; Zeiger, E.; Haworth, S.; Ivett, J.; Valencia, R.

1987-01-01

334

Protective Effects of Epigallocatechin Gallate after UV Irradiation in Cultured Human Retinal Pigment Epithelial Cells  

PubMed Central

Purpose To evaluate the protective effects of Epigallocatechin gallate (EGCG) against UV irradiation in cultured human retinal pigment epithelial (RPE) cells. Methods UV irradiation was produced by a UV lamp for 30 seconds with an irradiance of 3.3 mW/cm2. After 5 minutes and 1 hour, we administered different concentrations of EGCG (0, 5, 10, 15, 25, 50, 100 uM). The cell count was determined under a microscope using a counting chamber and the cell activity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Results The cell count of cultured human RPE cells after UV irradiation was markedly increased in the EGCG administration group, compared with the non-administrated group. The cell activity of the cultured human RPE cells after UV irradiation was markedly increased in the EGCG administration group and was increased in a dose-dependent way as determined by the MTT assay. Conclusions The administration of EGCG increased the cell count and the cell activity after UV irradiation in cultured human retinal pigment epithelial cells; this suggests that EGCG provided protection against UV damage in cultured human retinal pigmented epithelial cells.

Yang, Seong-Won; Lee, Byung Rae

2007-01-01

335

Date Palm Cell and Protoplast Culture  

Microsoft Academic Search

\\u000a This chapter describes the current status of cell and protoplast cultures in date palm (Phoenix dactylifera L.). Critically important steps toward plant regeneration from recalcitrant date palm protoplasts have been achieved in the\\u000a recent past. Callus regeneration was achieved in commercial cvs. Deglet Noor, Takerboucht, Barhee and Zaghloul. The use of\\u000a feeder layer was the main factor for inducing cell

A. Assani; D. Chabane; H. Shittu; N. Bouguedoura

336

Live-cell migration and adhesion turnover assays.  

PubMed

Fluorescence microscopy has revolutionized the way live-cell imaging is achieved. At the same time, it is also potentially harmful to a living specimen. Therefore, the specimen must be monitored for viability and health before, during, and after imaging sessions. Methods for monitoring cell viability and health will be discussed in this chapter. Another key to successful live-cell imaging is to minimize light exposure as much as possible. A summary of strategies for minimizing light exposure including maximizing the light throughput of the microscope and the sensitivity of light detection is presented. Various fluorescence microscopy techniques are presented with a focus on how the light is delivered to the sample (i.e., light density) and pros and cons for use with living specimens. The reader is also directed to other publications that go into these topics in more detail. Methods are described on how to prepare samples for single cell migration assays, how to measure cell migration rates (e.g., bright-field, semi-automated, and automated), and how to measure focal adhesion turnover rates. Details of how to correct images for background intensity and field-illumination uniformity artifacts for quantitative imaging are also described. Overall, this chapter will be helpful to scientists who are interested in imaging live specimens using fluorescence microscopy techniques. It will be of particular interest to anyone wanting to perform quantitative fluorescence imaging, and wanting to measure cell migration rates, and focal adhesion dynamics. PMID:23026997

Lacoste, J; Young, K; Brown, Claire M

2013-01-01

337

USE OF CELL CULTURE FOR EVALUATING NEUROTOXICITY  

EPA Science Inventory

This chapter familiarizes the reader with the need to develop, validate and utilize in vitro models to test chemicals for neurotoxic potential. he major advantages and disadvantages of using cell and tissue culture, factors which have stimulated and hampered the promulgation of i...

338

Wound Coverage by Cultured Skin Cells.  

National Technical Information Service (NTIS)

The major purpose of our work is to refine the technology for growth of human epidermal cells to achieve more rapid growth in vitro and easier handling of tissue cultured materials in clinics. It is also to evaluate the possibilities for the use of alloge...

M. Eisinger E. M. Duffy

1985-01-01

339

Wound Coverage by Cultured Skin Cells.  

National Technical Information Service (NTIS)

At the conclusion of a three year study on ways to improve wound healing by cultured epidermal grafts, we have found that: We were able to grow epidermal cells on collapsed collagen sponges. As a result, we can create a skin transplant with a quarter of t...

M. Eisinger

1988-01-01

340

Wound Coverage by Cultured Skin Cells.  

National Technical Information Service (NTIS)

The aim was to confirm and extend in vitro and in vivo studies reported last year and develop new means for wound treatment. For the studies in vitro we used different tissue culture techniques. Quantitative data were obtained by cell counts and incorpora...

M. Eisinger

1987-01-01

341

Intelligent Control for Cell Culture Processes  

Microsoft Academic Search

An Integrated Intelligent System is being developed for cell culture process control, which consists of several symbolic reasoning systems and numerical computation packages. These software programs are written in different languages and can be used independently. They are under the control of a supervisory expert system, namely, the Meta-System. The key issue to construct the Integrated Intelligent System is to

Ming Rao; Rafael Crus; Tao Yang; Tsung-Shann Jiang; Shaw S. Wang; Ik-K Wan Kim

1989-01-01

342

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.  

Code of Federal Regulations, 2010 CFR

... Tissue culture media for human ex vivo tissue and cell culture processing applications... Tissue culture media for human ex vivo tissue and cell culture processing applications...maintenance of tissues and cells of human origin. The solutions...

2010-04-01

343

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.  

Code of Federal Regulations, 2010 CFR

... Tissue culture media for human ex vivo tissue and cell culture processing applications... Tissue culture media for human ex vivo tissue and cell culture processing applications...maintenance of tissues and cells of human origin. The solutions...

2009-04-01

344

Isolation and expansion of human glioblastoma multiforme tumor cells using the neurosphere assay.  

PubMed

Stem-like cells have been isolated in tumors such as breast, lung, colon, prostate and brain. A critical issue in all these tumors, especially in glioblastoma mutliforme (GBM), is to identify and isolate tumor initiating cell population(s) to investigate their role in tumor formation, progression, and recurrence. Understanding tumor initiating cell populations will provide clues to finding effective therapeutic approaches for these tumors. The neurosphere assay (NSA) due to its simplicity and reproducibility has been used as the method of choice for isolation and propagation of many of this tumor cells. This protocol demonstrates the neurosphere culture method to isolate and expand stem-like cells in surgically resected human GBM tumor tissue. The procedures include an initial chemical digestion and mechanical dissociation of tumor tissue, and subsequently plating the resulting single cell suspension in NSA culture. After 7-10 days, primary neurospheres of 150-200 ?m in diameter can be observed and are ready for further passaging and expansion. PMID:22064695

Azari, Hassan; Millette, Sebastien; Ansari, Saeed; Rahman, Maryam; Deleyrolle, Loic P; Reynolds, Brent A

2011-10-30

345

Isolation of nuclei from skeletal muscle satellite cells and myofibers for use in chromatin immunoprecipitation assays.  

PubMed

Studies investigating mechanisms controlling gene regulation frequently examine specific DNA sequences using chromatin immunoprecipitation (ChIP) assays to determine whether specific regulatory factors or modified histones are present. While use of primary cells or cell line models for differentiating or differentiated tissue is widespread, the ability to assess factor binding and histone modification in tissue defines the events that occur in vivo and provides corroboration for studies in cultured cells. Many tissues can be analyzed with minimal modification to existing ChIP protocols that are designed for cultured cells; however, some tissues, such as skeletal muscle, are problematic in that accessibility of the cross-linking agent is limited. We describe a method to isolate skeletal muscle tissue nuclei suitable for use in ChIP protocols. Furthermore, we utilize a simple fractionation of digested skeletal muscle tissue that can separate mature myofibers from satellite cells, which are responsible for postnatal skeletal muscle regeneration, thereby allowing simultaneous preparation of nuclei from both cell types. PMID:22130858

Ohkawa, Yasuyuki; Mallappa, Chandrashekara; Vallaster, Caroline S Dacwag; Imbalzano, Anthony N

2012-01-01

346

Prevention and Detection of Mycoplasma Contamination in Cell Culture  

PubMed Central

One of the main problems in cell culture is mycoplasma infection. It can extensively affect cell physiology and metabolism. As the applications of cell culture increase in research, industrial production and cell therapy, more concerns about mycoplasma contamination and detection will arise. This review will provide valuable information about: 1. the ways in which cells are contaminated and the frequency and source of mycoplasma species in cell culture; 2. the ways to prevent mycoplasma contamination in cell culture; 3. the importance of mycoplasma tests in cell culture; 4. different methods to identify mycoplasma contamination; 5. the consequences of mycoplasma contamination in cell culture and 6. available methods to eliminate mycoplasma contamination. Awareness about the sources of mycoplasma and pursuing aseptic techniques in cell culture along with reliable detection methods of mycoplasma contamination can provide an appropriate situation to prevent mycoplasma contamination in cell culture.

Nikfarjam, Laleh; Farzaneh, Parvaneh

2012-01-01

347

Real-time analysis of endosomal lipid transport by live cell scintillation proximity assay  

PubMed Central

A scintillation proximity assay has been developed to study the endosomal trafficking of radiolabeled cholesterol in living cells. Mouse macrophages were cultured in the presence of tritiated cholesterol and scintillant microspheres. Microspheres were taken up by phagocytosis and stored in phagolysosomes. Absorption of tritium ? particles by the scintillant produces light signals that can be measured in standard scintillation counters. Because of the short range of tritium ? particles and for geometric reasons, scintillant microspheres detect only that fraction of tritiated cholesterol localized inside phagolysosomes or within a distance of ~600 nm. By incubating cultures in a temperature-controlled microplate reader, the kinetics of phagocytosis and cholesterol transport could be analyzed in near-real time. Scintillation signals were significantly increased in response to inhibitors of lysosomal cholesterol export. This method should prove a useful new tool for the study of endosomal trafficking of lipids and other molecules.

Stockinger, Walter; Castoreno, Adam B.; Wang, Yan; Pagnon, Joanne C.; Nohturfft, Axel

2007-01-01

348

Responses of the L5178Y mouse lymphoma cell forward mutation assay. V: 27 coded chemicals  

SciTech Connect

Twenty-seven chemicals were tested for their mutagenic potential in the L5178Y tk{sup +}/tk{sup {minus}} mouse lymphoma cell forward mutation assay. Cultures were exposed to the chemicals for 4 hr, then cultured for 2 days before plating in soft agar with or without trifluorothymidine (TFT), 3 {mu}g/ml. The chemicals were tested at least twice. Statistically significant responses were obtained with acid orange 10, aniline, benzaldehyde o-chloroaniline, chlorodibromomethane, cytembena, 1,2-dibromo-4-(1,2-dibromomethyl) cyclohexane, dieldrin, lithocholic acid, oxytetracycline, phenazopyridine HCl, 1phenyl-3-methyl-5-pyrazolone, sodium diethyldithiocarbamate, solvent yellow 14, tetraethylthiuram disulfide (disulfiram), 2,4-toluene diisocyanate, and 2,6-toluene diisocyanate. Apart from phenazopyridine HCl, acid orange 10, and solvent yellow 14, rat liver S9 mix was not a requirement for the mutagenic activity of these compounds.

McGregor, D.B.; Brown, A.G.; Howgate, S.; McBride, D.; Riach, C. (Inveresk Research International Limited, Musselburgh (Scotland)); Caspary, W.J. (National Inst. of Health, Research Triangle Park, NC (United States))

1991-01-01

349

Guidelines for the use and interpretation of assays for monitoring cell death in higher eukaryotes  

PubMed Central

Cell death is essential for a plethora of physiological processes, and its deregulation characterizes numerous human diseases. Thus, the in-depth investigation of cell death and its mechanisms constitutes a formidable challenge for fundamental and applied biomedical research, and has tremendous implications for the development of novel therapeutic strategies. It is, therefore, of utmost importance to standardize the experimental procedures that identify dying and dead cells in cell cultures and/or in tissues, from model organisms and/or humans, in healthy and/or pathological scenarios. Thus far, dozens of methods have been proposed to quantify cell death-related parameters. However, no guidelines exist regarding their use and interpretation, and nobody has thoroughly annotated the experimental settings for which each of these techniques is most appropriate. Here, we provide a nonexhaustive comparison of methods to detect cell death with apoptotic or nonapoptotic morphologies, their advantages and pitfalls. These guidelines are intended for investigators who study cell death, as well as for reviewers who need to constructively critique scientific reports that deal with cellular demise. Given the difficulties in determining the exact number of cells that have passed the point-of-no-return of the signaling cascades leading to cell death, we emphasize the importance of performing multiple, methodologically unrelated assays to quantify dying and dead cells.

Galluzzi, L; Aaronson, SA; Abrams, J; Alnemri, ES; Andrews, DW; Baehrecke, EH; Bazan, NG; Blagosklonny, MV; Blomgren, K; Borner, C; Bredesen, DE; Brenner, C; Castedo, M; Cidlowski, JA; Ciechanover, A; Cohen, GM; De Laurenzi, V; De Maria, R; Deshmukh, M; Dynlacht, BD; El-Deiry, WS; Flavell, RA; Fulda, S; Garrido, C; Golstein, P; Gougeon, M-L; Green, DR; Gronemeyer, H; Hajn?czky, G; Hardwick, JM; Hengartner, MO; Ichijo, H; Jaattela, M; Kepp, O; Kimchi, A; Klionsky, DJ; Knight, RA; Kornbluth, S; Kumar, S; Levine, B; Lipton, SA; Lugli, E; Madeo, F; Malorni, W; Marine, J-CW; Martin, SJ; Medema, JP; Mehlen, P; Melino, G; Moll, UM; Morselli, E; Nagata, S; Nicholson, DW; Nicotera, P; Nunez, G; Oren, M; Penninger, J; Pervaiz, S; Peter, ME; Piacentini, M; Prehn, JHM; Puthalakath, H; Rabinovich, GA; Rizzuto, R; Rodrigues, CMP; Rubinsztein, DC; Rudel, T; Scorrano, L; Simon, H-U; Steller, H; Tschopp, J; Tsujimoto, Y; Vandenabeele, P; Vitale, I; Vousden, KH; Youle, RJ; Yuan, J; Zhivotovsky, B; Kroemer, G

2009-01-01

350

Cell Kinase Activity Assay Based on Surface Enhanced Raman Spectroscopy  

PubMed Central

Kinases control many important aspects of cell behavior, such as signal transduction, growth/differentiation, and tumorogenesis. Current methods for assessing kinase activity often require specific antibodies, and/or radioactive labeling. Here we demonstrated a novel detection method to assess kinase activity based on surface enhanced Raman spectroscopy (SERS). Raman signal was obtained after amplification by silver nanoparticles. The sensitivity of this method was comparable to fluorescence measurement of peptide concentration. When purified kinase enzyme was used, the detection limit was comparable to conventional radio-labeling method. We further demonstrated the feasibility to measure kinase activity in crude cell lysate. We suggested this SERS-based kinase activity assay could be a new tool for biomedical research and application.

Yue, Zhicao; Zhuang, Fengfeng; Kumar, Rajar; Wong, Ieong; Cronin, Stephen B; Liu, Yi-Hsin

2009-01-01

351

Nick translation - a new assay for monitoring DNA damage and repair in cultured human fibroblasts  

SciTech Connect

An in vitro assay has been developed to detect DNA damage and repair following chemical treatment of human diploid fibroblasts. DNA damage is measured by following the Escherichia coli DNA polymerase I-catalyzed incorporation of radiolabeled deoxycytidine triphosphate (dCTP) into the DNA of lysolecithin-permeabilized cells. DNA strand breaks with free 3' OH termini serve as template sites for incorporation, and decrease of this incorporation with time, following removal of the test chemical, indicates loss (repair) of initial damage. Inhibition of the DNA excision repair process by the addition of the repair inhibitors arabinofuranosyl cytosine (ara-C) and hydroxyurea (HU) during the incubation period gives rise to an increased number of template sites, manifesting itself in increased incorporation and indicating the induction of long-patch excision repair. Results presented demonstrate that all 14 direct-acting carcinogens tested and 8 of 14 carcinogens requiring metabolic activation give positive indication of DNA damage, repair, or both. Eleven of 14 noncarcinogens tested were scored as negative, the other 3 having previously been shown to interact with cellular DNA. This assay is shown to have predictive capability at least equal to that of UDS assays but to allow a broader spectrum of genotoxic effects to be analyzed.

Snyder, R.D.; Matheson, D.W.

1985-01-01

352

Evaluation of the Strep A OIA assay versus culture methods: ability to detect different quantities of group A Streptococcus.  

PubMed

The Strep A OIA assay by Biostar (Boulder, Co., USA) is a unique optical immunoassay system for the rapid detection of Group A streptococcal carbohydrate. As part of a community-based pediatric cohort study of Group A Streptococcus (GAS) persistence following antibiotic therapy of pharyngitis, the performance of the Strep A OIA assay was compared with the amount of growth from standard throat swab culture methods. A total of 363 throat swabs taken over the course of the study was evaluated from 248 children between 2 and 18 years of age. Two culture methods were performed: an agar plate with the throat swab using Columbia agar base with 5% sheep blood incubated under an anaerobic environment for 48 h and Todd-Hewitt broth (THB) enhancement. The Strep A OIA was then performed. A total of 144 of 363 (39.7%) samples was positive for GAS by one or more of the laboratory tests across study visits: agar culture detected 132 of 144 (91.7%), THB culture detected 128 of 144 (88.9%), and the Strep A OIA assay detected 129 of 144 (89.6%). Complete agreement among all three laboratory tests was found for 333 of 363 (91.7%) of the samples. Agar culture results were comparable to THB cultures with a sensitivity of 96.9%, specificity of 96.6%, a positive predictive value of 93.9%, and a negative predictive value of 98.3%. Although the performance of the Strep A OIA assay had similar specificity (96.5%) and positive predictive value (93.8%) compared with the combined results of the two culture methods, the sensitivity (89.0%) and negative predictive value (93.6%) were lower. A significant difference (p < 0.001) was found in the ability of the Strep A OIA assay to detect agar culture-positive swabs that had a light growth (1+ or 2+) (63.0%) versus a moderate (3+) or heavy (4+) growth (98.1%) of GAS. Although the Strep A OIA assay allows GAS throat swab results to be reported an average of 24 h sooner than either of the cultures, the rapid assay was not as sensitive in detecting light growth GAS-positive cultures. PMID:10459477

Kuhn, S; Davies, H D; Katzko, G; Jadavji, T; Church, D L

1999-08-01

353

Structure-activity relationship study of host-specific phytotoxins (AM-toxin analogs) using a new assay method with leaves from apple meristem culture.  

PubMed

AM-toxins are host-specific phytotoxins of the Alternaria alternata apple pathotype, which induce necrosis on apple leaves. In this study, we developed a new assay to measure the necrotic activity of AM-toxin analogs using cultured leaves from meristem cells. This method was not only more sensitive to AM-toxin I, but also more reliable than the previous one that used tree leaves due to the homogeneous nature of cultured leaves and to the method of application of toxins. Using this assay method we investigated a structure-activity relationship of AM-toxin analogs synthesized in this study. Most residues and the macrocyclic ring structure were strictly recognized by AM-toxin putative receptor, whereas the L-Ala binding subsite of the receptor allowed for side chain structures with various stereoelectronic properties. These findings are important for designing ligands for further experimental probing of the nature of the receptor. PMID:11837655

Miyashita, M; Nakamori, T; Murai, T; Yonemoto, T; Miyagawa, H; Akamatsu, M; Ueno, T

354

Defined high protein content surfaces for stem cell culture.  

PubMed

Unlocking the clinical potential of stem cell based therapies requires firstly elucidation of the biological mechanisms which direct stem cell fate decisions and thereafter, technical advances which allow these processes to be driven in a fully defined culture environment. Strategies for the generation of defined surfaces for human embryonic stem cell (hESC) and mesenchymal stem cell (MSC) culture remain in their infancy. In this paper we outline a simple, effective and efficient method for presenting proteins or peptides on an otherwise non-fouling Layer-by-Layer (LbL) self-assembled surface of hyaluronic acid (HA) and chitosan (CHI). We are able to generate a surface that has both good temporal stability and the ability to direct biological outcomes based on its defined surface composition. Surface functionalization is achieved through suspending the selected extracellular matrix (ECM) protein domain or extracted full-length protein in buffer containing a cross-linking agent (N-hydroxysulfosuccinimide/N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride) over the LbL HA-CHI surface and then allowing the solvent to evaporate overnight. This simple, but important step results in remarkable protein deposition efficiencies often exceeding 50%, whereas traditional cross-linking methods result in such poor deposition of non-collagenous proteins that a.) quantification of bound amounts of protein is outside the resolution of commonly utilized protein assays, and b.) these surfaces are both unable to support cell attachment and growth. The utility of the protein-modified HA-CHI surfaces is demonstrated through the identification of specific hESC attachment efficiencies and through directing MSC osteogenic outcomes on these fully defined surfaces. This simple and scalable method is shown to enable the development of defined stem cell culture conditions, as well as the elucidation of the fundamental biological processes necessary for the realization of stem cell based therapies. PMID:20378164

Doran, Michael R; Frith, Jessica E; Prowse, Andrew B J; Fitzpatrick, Jane; Wolvetang, Ernst J; Munro, Trent P; Gray, Peter P; Cooper-White, Justin J

2010-04-08

355

Performance evaluation of 3D polystyrene 96-well plates with human neural stem cells in a calcium assay.  

PubMed

In this study, we have generated a high-throughput screening (HTS)-compatible 3D cell culture platform by chemically "welding" polystyrene scaffolds into standard 2D polystyrene 96-well plates. The variability of scaffolds was minimized by introducing automation into the fabrication process. The fabricated 3D cell culture plates were compared with several commercially available 3D cell culture platforms with light and scanning electron microscopy. Voltage-gated calcium channel functionality was used to access the Z' factors of all plates, including a 2D standard plate control. It was found that with the No-Wash Fluo-4 calcium assay and neural progenitor cells, all plates display acceptable Z' factors for use in HTS. The plates with "welded" polystyrene scaffolds have several advantages, such as being versatile and economical, and are ready to use off the shelf. These characteristics are especially desired in HTS preclinical drug discovery applications. PMID:22496208

Lai, Yinzhi; Kisaalita, William S

2012-04-10

356

Nitrogen Metabolism in Plant Cell Suspension Cultures  

PubMed Central

Certain amino acids inhibit growth of tobacco (Nicotiana tabacum L. var. xanthi), tomato (Lycopersicon esculentum) carrot (Daucus carota), and soybean (Glycerine max L. co. Mandarin) cell cultures when nitrate or urea are the nitrogen sources but not when ammonia is the nitrogen source. These amino acids also inhibit development of nitrate reductase activity (NADH:nitrate oxidoreductase EC 1.6.6.1) in tobacco and tomato cultures. Threonine, the most inhibitory amino acid, also inhibits nitrate uptake in tobacco cells. Arginine, and some other amino acids, abolish the inhibition effects caused by other amino acids. We suggest that amino acids inhibit assimilation of intracellular ammonium into amino acids in cells grown on nitrate or urea.

Behrend, Josef; Mateles, Richard I.

1975-01-01

357

Portable microcontact printing device for cell culture.  

PubMed

In this work, we developed a portable device to perform microcontact printing in a safety cabinet for cell culture. The device was designed to be small and non-bulky, easy to sterilize, while not requiring the use of electricity, and which requires very little manual handling. Moreover, the portable microcontact printer is reproducibly fabricated with a rapid prototyping system, and allows for the easy micropatterning of biomolecules with a resolution ranging from 20 to 500 ?m. This opens new horizons in the direct and simple micropatterning of culture dishes and the mimicking and biofabrication of complex architectures of tissues. PMID:20817249

Elloumi-Hannachi, Imen; Maeda, Masanori; Yamato, Masayuki; Okano, Teruo

2010-12-01

358

Plant cell cloning and culture products.  

PubMed

Biotechnological developments in the use of plant cells as sources of biochemicals have now brought several applications within commercial range. Plant propagation has developed faster commercially, but now requires similar biotechnology to enable the automated production of large numbers of plants at low cost. Although some of the enabling technology has been developed for pregerminated seeds this has not been coupled to production of plantlets in bioreactors. Our present lack of knowledge of how to control gene expression in plant cells, which stems from our ignorance of the organization and regulation of the plant genome, is a critical factor limiting all applications of plant cell cultures. PMID:6443753

Jones, L H

1983-01-01

359

Real-time PCR assays for genus-specific detection and quantification of culturable and non-culturable mycobacteria and pseudomonads in metalworking fluids  

Microsoft Academic Search

Genus-specific real-time PCR assays were developed and optimized for the direct culture-independent detection and quantification of Mycobacteria and Pseudomonads in contaminated metalworking fluids (MWF) and the results were compared with conventional culturing using selective media. It included optimization of the direct DNA isolation from the fluid matrix and the amplification conditions using genus-specific primers. Mycobacterium-specific primers based on 65-kDa heat

Izhar U. H. Khan; Jagjit S. Yadav

2004-01-01

360

Ten commandments for preventing contamination of primary cell cultures  

Microsoft Academic Search

Procedures for preventing contamination in primary cell cultures must be carefully defined and strictly followed in order to obtain healthy cells. Protocols have been developed and refined in our laboratory for establishing primary cultures of muscle and fat stem cells without contamination from a variety of animals. Contamination of cell cultures is not only frustrating, but is also very expensive

Janet L. Vierck; Katherine Byrne; Priya S. Mir; Michael V. Dodson

2000-01-01

361

Genomics in mammalian cell culture bioprocessing.  

PubMed

Explicitly identifying the genome of a host organism including sequencing, mapping, and annotating its genetic code has become a priority in the field of biotechnology with aims at improving the efficiency and understanding of cell culture bioprocessing. Recombinant protein therapeutics, primarily produced in mammalian cells, constitute a $108 billion global market. The most common mammalian cell line used in biologic production processes is the Chinese hamster ovary (CHO) cell line, and although great improvements have been made in titer production over the past 25 years, the underlying molecular and physiological factors are not well understood. Confident understanding of CHO bioprocessing elements (e.g. cell line selection, protein production, and reproducibility of process performance and product specifications) would significantly improve with a well understood genome. This review describes mammalian cell culture use in bioprocessing, the importance of obtaining CHO cell line genetic sequences, and the current status of sequencing efforts. Furthermore, transcriptomic techniques and gene expression tools are presented, and case studies exploring genomic techniques and applications aimed to improve mammalian bioprocess performance are reviewed. Finally, future implications of genomic advances are surmised. PMID:22079893

Wuest, Diane M; Harcum, Sarah W; Lee, Kelvin H

2011-11-04

362

The novel herbicide oxaziclomefone inhibits cell expansion in maize cell cultures without affecting turgor pressure or wall acidification.  

PubMed

Oxaziclomefone [OAC; IUPAC name 3-(1-(3,5-dichlorophenyl)-1-methylethyl)-3,4-dihydro-6-methyl-5-phenyl-2H-1,3-oxazin-4-one] is a new herbicide that inhibits cell expansion in grass roots. Its effects on cell cultures and mode of action were unknown. In principle, cell expansion could be inhibited by a decrease in either turgor pressure or wall extensibility. Cell expansion was estimated as settled cell volume; cell division was estimated by cell counting. Membrane permeability to water was measured by a novel method involving simultaneous assay of the efflux of (3)H(2)O and [(14)C]mannitol from a 'bed' of cultured cells. Osmotic potential was measured by depression of freezing point. OAC inhibited cell expansion in cultures of maize (Zea mays), spinach (Spinacia oleracea) and rose (Rosa sp.), with an ID(50) of 5, 30 and 250 nm, respectively. In maize cultures, OAC did not affect cell division for the first 40 h. It did not affect the osmotic potential of cell sap or culture medium, nor did it impede water transport across cell membranes. It did not affect cells' ability to acidify the apoplast (medium), which may be necessary for 'acid growth'. As OAC did not diminish turgor pressure, its ability to inhibit cell expansion must depend on changes in wall extensibility. It could be a valuable tool for studies on cell expansion. PMID:16219072

O'Looney, Nichola; Fry, Stephen C

2005-11-01

363

Enzymatic measurement of phosphatidylserine in cultured cells.  

PubMed

Phosphatidylserine (PS) is a quantitatively minor membrane phospholipid involved in diverse cellular functions. In this study, we developed a new fluorometric method for measuring PS using combinations of specific enzymes and Amplex Red. The calibration curve for PS measurement was linear and hyperbolic at low (0-50 µM) and high (50-1000 µM) concentrations, respectively, and the detection limit was 5 µM (50 pmol in the reaction mixture). This assay quantified PS regardless of the chain length and the number of double bonds. We applied this new method to the determination of PS content in HEK293 cells, which was validated by a recovery study and comparison with TLC-phosphorus assay. We showed that the PS content was high in sparse cells. The overexpression of PS synthase 1 elevated not only the cellular PS content but also the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) contents, suggesting the conversion of PS into PE and the enhancement of PC production. This new assay for PS measurement is simple, specific, sensitive, and high throughput, and it will be useful to clarify the metabolism and biological functions of PS. PMID:22100437

Morita, Shin-ya; Shirakawa, Sachimi; Kobayashi, Yukiko; Nakamura, Keiko; Teraoka, Reiko; Kitagawa, Shuji; Terada, Tomohiro

2011-11-18

364

Aluminum silicate toxicity in cell cultures.  

PubMed

To assess the cytotoxicity of four clays containing an aluminum silicate--montmorillonite, bentonite, kaolinite and erionite--we used human umbilical vein endothelial, N1E-115 neuroblastoma, and ROC-1 oligodendroglial cells. Morphological examination, lactate dehydrogenase release and fatty acid release were used as indices of trauma. The clays were added in suspension to the cell cultures at concentrations of 0.1, 0.03 and 0.01 mg/ml of medium and the cells were incubated for 1, 6 and 24 h. The clays did not lyse ROC-1 and N1E-115 cells and did not cause a dose-dependent increase in fatty acid levels at 24 h. There were no significant increases in lactate dehydrogenase activity in N1E-115 neuroblastoma or ROC-1 oligodendroglial cells. In human umbilical vein endothelial cells, montmorillonite, kaolinite and bentonite caused a dose-dependent increase in fatty acids at 24 h. All three clays caused cell lysis. We postulate that the cytotoxicity of the clays containing an aluminum silicate towards endothelial cells may disrupt the blood-brain barrier in the affected areas, allowing the entry of the clay particle into the brain. Aluminum silicate clays caused a dose-dependent release of fatty acids in human umbilical vein endothelial cells. The clays also caused lysis of these cells. ROC-1 oligodendroglia and N1E-115 neuroblastoma cells were not lysed by the clays, suggesting that this is not a general phenomenon. PMID:8397348

Murphy, E J; Roberts, E; Horrocks, L A

1993-07-01

365

The pesticide methoxychlor decreases myotube formation in cell culture by slowing myoblast proliferation.  

PubMed

We studied the effect of the estrogenic pesticide methoxychlor (MXC) on skeletal muscle development using C2C12 cell culture. Myoblast cultures were exposed to various concentrations of MXC at various times during the process of myoblast fusion into myotubes. We observed that MXC exposure decreased myotube formation. In addition, we observed myoblasts with cytoplasmic vacuoles in cultures exposed to MXC. Because cytoplasmic vacuoles can be characteristic of cell death, apoptosis assays and trypan blue exclusion assays were performed. We found no difference in the frequency of apoptosis or in the frequency of cell death for cultures exposed to MXC and untreated cultures. Collectively, these results indicate that MXC exposure decreases myotube formation without causing cell death. In contrast, when cell proliferation was assessed, untreated cultures had a myoblast proliferation rate 50% greater than cultures exposed to MXC. We conclude that MXC decreases myotube formation at least in part by slowing myoblast proliferation. Furthermore, we suggest that direct exposure to MXC could affect skeletal muscle development in animals or humans, in addition to the defects in reproductive development that have previously been reported. PMID:17314029

Steffens, Bradley W; Batia, Lyn M; Baarson, Chad J; Choi, Chang-Kun Charles; Grow, Wade A

2007-01-17

366

Optimal time for passaging neurospheres based on primary neural stem cell cultures.  

PubMed

Cultured neural stem cells (NSCs) provide a powerful means for investigating central nervous system disease, neuron development, differentiation, and regeneration. To obtain sufficient neurospheres, subculturing is essential following establishment of the primary NSC culture. Passaging the primary neurospheres is a key issue that is often ignored. We evaluated the influence of different passaging schedules on primary cultured NSCs. Passaging was performed on day 5, 7 or 9. We observed more neurospheres with diameters of 200-250 ?m on day 7 than on day 5 or 9. Prolonging the time of primary culture reduced the cell metabolic activity by the MTT assay and cell proliferation by colony-forming assay and the differentiation to neurons from cells at P2 and later decreased. Additionally, more cells were in G0/G1 phase, and higher expression of p16 ( INK4a ) and lower expression of cyclin D1 was found when the time of primary culture was prolonged to 9 days compared to 7-days cultures. Thus, in this study, we established that the optimal time for subculturing aggregated NSCs was on day 7 based on the primary culture. PMID:21858692

Xiong, Fangling; Gao, Huasong; Zhen, Yan; Chen, Xue; Lin, Weiwei; Shen, Jianhong; Yan, Yaohua; Wang, Xiaodong; Liu, Mei; Gao, Yilu

2011-08-21

367

Cell division modulates prion accumulation in cultured cells  

PubMed Central

The phenotypic effect of prions on host cells is influenced by the physical properties of the prion strain and its level of accumulation. In mammalian cell cultures, prion accumulation is determined by the interplay between de novo prion formation, catabolism, cell division, and horizontal cell-to-cell transmission. Understanding this dynamic enables the analytical modeling of protein-based heritability and infectivity. Here, we quantitatively measured these competing effects in a subline of neuroblastoma (N2a) cells and propose a concordant reaction mechanism to explain the kinetics of prion propagation. Our results show that cell division leads to a predictable reduction in steady-state prion levels but not to complete clearance. Scrapie-infected N2a cells were capable of accumulating different steady-state levels of prions, dictated partly by the rate of cell division. We also show that prions in this subline of N2a cells are transmitted primarily from mother to daughter cells, rather than horizontal cell-to-cell transmission. We quantitatively modeled our kinetic results based on a mechanism that assumes a subpopulation of prions is capable of self-catalysis, and the levels of this subpopulation reach saturation in fully infected cells. Our results suggest that the apparent effectiveness of antiprion compounds in culture may be strongly influenced by the growth phase of the target cells.

Ghaemmaghami, Sina; Phuan, Puay-Wah; Perkins, Beth; Ullman, Julie; May, Barnaby C. H.; Cohen, Fred E.; Prusiner, Stanley B.

2007-01-01

368

UVA-induced oxidative stress in single cells probed by autofluorescence modifications, cloning assay, and comet assay  

NASA Astrophysics Data System (ADS)

Cell damage by low-power 365 nm radiation of a 50 W high-pressure mercury microscopy lamp was studied. UVA exposure to CHO cells resulted for radiant exposures greater than 10 kJ/m2 in significant modifications of NADH-attributed autofluorescence and in inhibition of cell division. Single cell gel electrophoresis (comet assay) revealed UVA-induced single strand DNA breaks. According to these results, UVA excitation radiation in fluorescence microscopy may damage cells. This has to be considered in vital cell microscopy, e.g. in calcium measurements.

Koenig, Karsten; Krasieva, Tatjana; Bauer, Eckhard; Fiedler, Ulrich; Berns, Michael W.; Tromberg, Bruce J.; Greulich, Karl O.

1996-01-01

369

Plant cell cultures: Chemical factories of secondary metabolites  

Microsoft Academic Search

This review deals with the production of high-value secondary metabolites including pharmaceuticals and food additives through plant cell cultures, shoot cultures, root cultures and transgenic roots obtained through biotechnological means. Plant cell and transgenic hairy root cultures are promising potential alternative sources for the production of high-value secondary metabolites of industrial importance. Recent developments in transgenic research have opened up

S Ramachandra Rao; G. A Ravishankar

2002-01-01

370

Performance of Karyologic Studies on Primary Human Cell Cultures.  

National Technical Information Service (NTIS)

Primary cell cultures were established from lung, skin and kidney tissues from four aborted normal human fetuses. Karyologic studies were performed on these primary cell cultures up to 4th culture passage except for the first two fetal kidney cultures. Th...

L. Y. F. Hsu

1975-01-01

371

Method of determining the number of cells in cell culture  

SciTech Connect

This patent describes a color-sensitivity method for determining the number of cells in in vitro cell culture at a sensitivity as low as about 100 or about 500 cells. It comprises lysing the cells and incubating the lysate with p-nitrophenyl phosphate at acid pH for a predetermined period of time at a temperature of from about 35{degrees} to about 38{degrees}C. and then measuring the color development at 400 to 420 nanometers and correlating the color development with cell number by comparing with a control standard of known cell number.

Connolly, D.T.

1990-06-12

372

Determining cell number during cell culture using the Scepter cell counter.  

PubMed

Counting cells is often a necessary but tedious step for in vitro cell culture. Consistent cell concentrations ensure experimental reproducibility and accuracy. Cell counts are important for monitoring cell health and proliferation rate, assessing immortalization or transformation, seeding cells for subsequent experiments, transfection or infection, and preparing for cell-based assays. It is important that cell counts be accurate, consistent, and fast, particularly for quantitative measurements of cellular responses. Despite this need for speed and accuracy in cell counting, 71% of 400 researchers surveyed(1) who count cells using a hemocytometer. While hemocytometry is inexpensive, it is laborious and subject to user bias and misuse, which results in inaccurate counts. Hemocytometers are made of special optical glass on which cell suspensions are loaded in specified volumes and counted under a microscope. Sources of errors in hemocytometry include: uneven cell distribution in the sample, too many or too few cells in the sample, subjective decisions as to whether a given cell falls within the defined counting area, contamination of the hemocytometer, user-to-user variation, and variation of hemocytometer filling rate(2). To alleviate the tedium associated with manual counting, 29% of researchers count cells using automated cell counting devices; these include vision-based counters, systems that detect cells using the Coulter principle, or flow cytometry(1). For most researchers, the main barrier to using an automated system is the price associated with these large benchtop instruments(1). The Scepter cell counter is an automated handheld device that offers the automation and accuracy of Coulter counting at a relatively low cost. The system employs the Coulter principle of impedance-based particle detection(3) in a miniaturized format using a combination of analog and digital hardware for sensing, signal processing, data storage, and graphical display. The disposable tip is engineered with a microfabricated, cell- sensing zone that enables discrimination by cell size and cell volume at sub-micron and sub-picoliter resolution. Enhanced with precision liquid-handling channels and electronics, the Scepter cell counter reports cell population statistics graphically displayed as a histogram. PMID:22158024

Ongena, Kathleen; Das, Chandreyee; Smith, Janet L; Gil, Sónia; Johnston, Grace

2010-11-26

373

Cryopreservation of bacterial vegetative cells used in antibiotic assay.  

PubMed

A long-term cryopreservation study of vegetative cells of Micrococcus lutea ATCC 9341a, Micrococcus lutea ATCC 15957, and Staphylococcus epidermidis ATCC 12228 cells, used in our antibiotic bioassay procedure, was conducted. The cryoprotective abilities of 1% methylcellulose solution and a 15% glycerol solution at -14 degrees C were determined. More organisms remained viable in 1% methylcellulose than in 15% glycerol. Overall survival of Staphylococcus epidermidis ATCC 12228 after 365 days was 1.5 logs lower than the other 2 organisms. The sensitivity and the resistance of the preserved organisms to various antibiotics did not change. The methodology is simple and inexpensive, saves analytical time, and avoids risk of contamination and sudden loss of a well-characterized culture. PMID:7580342

Reamer, R; Dey, B P; Thaker, N

374

Effects of Homocysteine on Smooth Muscle Cell Proliferation in Both Cell Culture and Artery Perfusion Culture Models  

Microsoft Academic Search

Background. Hyperhomocysteinemia is associated with increased risk for vascular disease. However, the pathogenic mechanisms of homocysteine are largely unknown. We evaluated the effects of homocysteine on smooth muscle cell (SMC) and endothelial cell proliferation in cell culture and on SMC proliferation of balloon angioplasty-injured arteries in a perfusion culture model.Methods. Human and pig SMCs and endothelial cells were cultured with

Changyi Chen; Michael E. Halkos; Scott M. Surowiec; Brian S. Conklin; Peter H. Lin; Alan B. Lumsden

2000-01-01

375

Some properties of Bomirski Ab amelanotic melanoma cells, which underwent spontaneous melanization in primary cell culture  

Microsoft Academic Search

Summary Four types of the Bomirski Ab amelanotic melanoma primary cell culture, differing in the presence of calf serum in the medium and in the cell number used for starting the culture, were employed in the study. In all types of cell culture, rapid melanization occurred in the cytoplasm of the cultured cells. Calf serum in the culture medium stimulated

Andrzej Stomifiski

1985-01-01

376

Acetaldehyde and hexanaldehyde from cultured white cells  

PubMed Central

Background Noninvasive detection of innate immune function such as the accumulation of neutrophils remains a challenge in many areas of clinical medicine. We hypothesized that granulocytes could generate volatile organic compounds. Methods To begin to test this, we developed a bioreactor and analytical GC-MS system to accurately identify and quantify gases in trace concentrations (parts per billion) emitted solely from cell/media culture. A human promyelocytic leukemia cell line, HL60, frequently used to assess neutrophil function, was grown in serum-free medium. Results HL60 cells released acetaldehyde and hexanaldehyde in a time-dependent manner. The mean ± SD concentration of acetaldehyde in the headspace above the cultured cells following 4-, 24- and 48-h incubation was 157 ± 13 ppbv, 490 ± 99 ppbv, 698 ± 87 ppbv. For hexanaldehyde these values were 1 ± 0.3 ppbv, 8 ± 2 ppbv, and 11 ± 2 ppbv. In addition, our experimental system permitted us to identify confounding trace gas contaminants such as styrene. Conclusion This study demonstrates that human immune cells known to mimic the function of innate immune cells, like neutrophils, produce volatile gases that can be measured in vitro in trace amounts.

Shin, Hye-Won; Umber, Brandon J; Meinardi, Simone; Leu, Szu-Yun; Zaldivar, Frank; Blake, Donald R; Cooper, Dan M

2009-01-01

377

Effect of Dietary Inducer Dimethylfumarate on Glutathione in Cultured Human Retinal Pigment Epithelial Cells  

Microsoft Academic Search

PURPOSE. To determine the effect of dimethylfumarate (DMF), an inducer of glutathione (GSH)- dependent detoxification, on intracellular GSH levels in cultured human retinal pigment epithelium (hRPE) cells, its mechanism of action, and its effect on hRPE cells subjected to oxidative injury. METHODS. Established hRPE cell lines were treated with DMF and assayed by high-pressure liquid chromatography for intracellular and extracellular

Kasey C. Nelson; Joanne L. Carlson; Melanie L. Newman; Paul Sternberg; Dean P. Jones; Terrance J. Kavanagh; Dolores Diaz; Jiyang Cai; Mei Wu

378

Phosphorylation of retinoblastoma protein assayed in individual HL-60 cells during their proliferation and differentiation.  

PubMed

Expression of pRb and its state of phosphorylation were immunocytochemically assayed in individual HL-60 cells during their proliferation and after induction of differentiation, using mAb which detects hypophosphorylated pRb (pRbP-) combined with mAb which reacts with pRb regardless of its phosphorylation (total pRb; pRbT). Correlated measurements of pRbP-, pRbT, a ratio of pRbP-/pRbT, and cellular DNA content by flow cytometry revealed expression of total pRb and its phosphorylation state vis-ŕ-vis the cell cycle position. Following mitosis (during the exponential phase of cell growth) a mixture of hypo- and hyperphosphorylated pRb was present within the cell for less than 2 h, i.e., early in G1; no hypophosphorylated pRb was detected throughout remainder of the cycle. Cellular pRb content was increasing primarily during G1 and the cell entrance to S was correlated with attainment of a distinct threshold level of pRb. No correlation was seen between the content of pRb per cell and its state of phosphorylation during G1. Cell differentiation whether induced by 1,25-dihydroxyvitamin D3, retinoic acid, or phorbol myristate acetate led to cell arrest primarily in G0/1. The G0/1 cells in these cultures, compared to G1 cells from the untreated cultures, had increased level of both pRbT and pRbP-. However, because the relative increase of pRbP- was disproportionally greater than of pRbT, the pRbP-/pRbT ratio of the differentiating cells was markedly elevated. The cells that still were in S and G2/M in the differentiating cultures also showed the presence of hypophosphorylated pRb. Our data suggest that the mechanism of irreversible cell cycle arrest during terminal differentiation involves both the increase in content of pRb and dephosphorylation of pRb already present within the cell. This provides a large pool of hypophosphorylated pRb that can effectively remove all free E2F, thereby precluding activation of the genes whose transcription is needed to pass the G1 restriction point. In contrast to terminal differentiation the transient quiescence (G0 state) manifests only by dephosphorylation of pRb, without a change in its cellular level. PMID:9770352

Juan, G; Li, X; Darzynkiewicz, Z

1998-10-10

379

Effect of antioxidants on PDT treatment of cultured tumor cells  

NASA Astrophysics Data System (ADS)

Lipid peroxidation (LP) is involved in cell damage induced by photodynamic treatment (PDT) sensitized by some lipophylic porphyrins. We investigated an effect of lipophylic antioxidant (alpha) -tocopherol and its water-soluble analog, trolox, on meta-tetra(hydroxyphenyl)chlorin (mTHPC) sensitized PDT (413 nm) of cultured human colon adenocarcinoma cells (HT29). Cell survival was measured by the 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide conversion to farmazan (MTT assay). Both antioxidants in concentrations lower than 0.1 mM did not affect photokilling of HT29 cells. These data might suggest that LP is not of crucial importance in cell damage photosensitized by mTHPC. One mM (alpha) -tocopherol or trolox decreased cell survival by ca. 15 and 13% respectively. Both antioxidants increased PDT- induced damage of HT29. Potentiation was evident as the decrease in the initial shoulder part of fluence dependence curve. We propose that antioxidants at height, pro-oxidant concentrations can potentiate PDT induced killing of tumor cells.

Melnikova, Vladislava; Bezdetnaya, Lina; Belitchenko, Irina; Potapenko, Alexander; Merlin, Jean-Louis; Guillemin, Francois H.

1998-05-01

380

Neonatal Rat Heart Cells Cultured in Simulated Microgravity.  

National Technical Information Service (NTIS)

In vitro characteristics of cardiac cells cultured in simulated microgravity are reported. Tissue culture methods performed at unit gravity constrain cells to propagate, differentiate, and interact in a two dimensional (2D) plane. Neonatal rat cardiac cel...

R. E. Akins N. A. Schroedl S. R. Gonda C. R. Hartzell

1994-01-01

381

Recombinant Protein Production and Insect Cell Culture and Process.  

National Technical Information Service (NTIS)

A process has been developed for recombinant production of selected polypeptides using transformed insect cells cultured in a horizontally rotating culture vessel modulated to create low shear conditions. A metabolically transformed insect cell line is pr...

G. Spaulding T. Prewett T. Goodwin K. Francis A. Andrews

1993-01-01

382

Apparent functional independence of the mitochondrial and nuclear transcription systems in cultured human cells  

Microsoft Academic Search

We have constructed a series of reporter constructs which test the effects of sequence elements from the control region of human mitochondrial DNA on expression in the nucleus, as assayed by transient expression in cultured human cells. The mitochondrial heavy-strand promoter (HSP) was unable to function as a promoter in nuclear DNA. Neither the HSP, nor the binding region for

Richard Sewards; Bryony Wiseman; Howard T. Jacobs

1994-01-01

383

Assessment of Chlamydia trachomatis Prevalence by Cell Culture and Transcription-Mediated Amplification in Symptomatic Women  

Microsoft Academic Search

Objective: The frequency of Chlamydia trachomatis in women with mucopurulent discharge was determined by a cell culture technique and a transcription-mediated amplification (TMA) assay in endocervical swab specimens. Subjects and Methods: Endocervical swab specimens were obtained from 116 symptomatic patients with genitourinary complaints or abdominal pain. All of the women were married, with an age range of between 19 and

Candan Cicek; Imre Altuglu; Tijen Ozacar; Kahraman Kolday; Namik Demir; Altinay Bilgic

2004-01-01

384

Enzyme-Based Flow Injection Analysis System for Glutamine and Glutamate in Mammalian Cell Culture Media  

Microsoft Academic Search

We present the setup of a flow injection analysis system designed for on-line monitoring of glutamate and glutamine. These amino acids represent a major energy source in mammalian cell culture. A cycling assay consisting of glutamate dehydrogenase and aspartate aminotransferase produces NADH proportional to the glutamate concentration in the sample. NADH is then measured spectrophotometrically. Glutamine is determined by conversion

Christian Mayer; Alexandra Frauer; Thomas Schalkhammer; Fritz Pittner

1999-01-01

385

THE ACTIVITY OF ENVIRONMENTAL SAMPLES IN A CELL CULTURE TEST FOR ASBESTOS TOXICITY  

EPA Science Inventory

The inhibition of colony-forming efficiency of cultured human embryonic intestine-derived epithelial (I-407) cells was utilized in order to assay the toxic potential of six coded samples of particulate matter provided by the United States Environmental Protection Agency (EPA). Th...

386

Hydrocortisone effect of arylsulfatase A in primary mouse brain cell cultures  

SciTech Connect

The primary goal of this study was to study the mechanism of action of hydrocortisone (HC) on arylsulfatase A (ASA) in primary cultures of cells that were dissociated from the brains of embryonic mice. Cells were cultured in a defined medium in the absence or in the presence of 3 ..mu..M HC. The specific activity of ASA in nontreated cells was 1.297 U/mg (U = ..mu..mol/hr) while the value for the HC-treated cells was 0.783 U/mg. The authors data shows that HC inhibits ASA activity in these cultures cells (p < 0.001). The determination of the ASA enzyme activity was assayed primarily with the artificial substrate p-nitrocatechol sulfate. However, the natural substrate (cerebroside /sup 35/S-sulfate) also as active and correlated linearly with the activity of p-nitrocatechol sulfate. Purified ASA was isolated from calf brains and used to generate an antibody (Ab) against ASA. The specificity of the Ab for the ASA protein of cell cultures was tested in Ouchterlony double immunodiffusion studies. The Ab was used in a competitive enzyme-linked immunosorbent assay to quantify the number of ASA molecules in the cell extracts from the embryonic mouse cell cultures. Preliminary data suggest that HC decreases the number of ASA molecules.

Marcelo, A.; Pieringer, R.A.

1986-05-01

387

Phosphoribosylpyrophosphate Synthesis in Cultured Human Cells  

Microsoft Academic Search

Phosphoribosylpyrophosphate (PRPP) concentrations and PRPP synthetase activity were studied in cultured human fibroblasts with control and mutant hypoxanthine-guanine phosphoribosylpyrophosphate (HPRT) activity. The PRPP concentrations increased 20- to 50-fold and PRPP synthetase activity 3-fold in cells from patients with the Lesch-Nyhan syndrome when aminopterin, an inhibitor of de novo purine synthesis, was added to the medium. Concentrations of PRPP and PRPP

Paul J. Benke; David Dittmar

1977-01-01

388

Cell Culture-Derived Influenza Vaccines  

Microsoft Academic Search

\\u000a Conventional egg-based vaccine manufacture has provided decades of safe and effective influenza vaccines using the technologies\\u000a of the 1930–1960s. Concerns over the vulnerability of the egg supply in the case of a pandemic with a high pathogenicity avian\\u000a influenza strain have spurred the development and licensure of mammalian cell culture-based influenza vaccines, the first\\u000a major technological innovation in influenza vaccine

Philip R. Dormitzer

389

Cytotoxicity of root canal sealers on endothelial cell cultures.  

PubMed

This study evaluated, in vitro, the cytotoxicity of six root canal sealers after 12, 24 and 72 h of contact time, using an endothelial ECV-304 cell line. The MTT assay was used for analysis of cell viability. Twelve specimens of each sealer were prepared and randomly assigned to 6 groups according to the commercial brands (n=4/time). A control group was also formed, which was not subjected to the contact with sealers. To assess the effects of sealers on endothelial cells, the specimens were placed in culture plate wells and incubated at 37°C with 5% CO2 and 100% humidity. MTT assays were performed in quadruplicate after 12, 24 and 72 h of contact of the sealer specimens with monolayers. Statistical analysis was performed by two-way ANOVA with Bonferroni post-hoc test at a significance level of 5%. Analysis of absorbance in the experimental groups showed that GuttaFlow presented the lowest cytotoxicity, with a mean absorbance of 0.048, followed by Pulp Canal Sealer (0.038), Sealer 26 (0.038), Endo Densell (0.036) and Pulp Fill (0.035). The control group had a mean absorbance of 0.098. Based on the results, Endofill and GuttaFlow were the most and the least cytotoxic sealers, respectively. PMID:23657407

Martins, Vagner José Medeiros; Lins, Renata Ximenes; Berlinck, Teresa Cristina Ávila; Fidel, Rivail Antônio Sérgio

2013-01-01

390

Reversible gelling culture media for in-vitro cell culture in three-dimensional matrices  

DOEpatents

A gelling cell culture medium useful for forming a three dimensional matrix for cell culture in vitro is prepared by copolymerizing an acrylamide derivative with a hydrophilic comonomer to form a reversible (preferably thermally reversible) gelling linear random copolymer in the form of a plurality of linear chains having a plurality of molecular weights greater than or equal to a minimum gelling molecular weight cutoff, mixing the copolymer with an aqueous solvent to form a reversible gelling solution and adding a cell culture medium to the gelling solution to form the gelling cell culture medium. Cells such as chondrocytes or hepatocytes are added to the culture medium to form a seeded culture medium, and temperature of the medium is raised to gel the seeded culture medium and form a three dimensional matrix containing the cells. After propagating the cells in the matrix, the cells may be recovered by lowering the temperature to dissolve the matrix and centrifuging.

An, Yuehuei H. (Charleston, SC); Mironov, Vladimir A. (Mt. Pleasant, SC); Gutowska, Anna (Richland, WA)

2000-01-01

391

A flounder ( Paralichthys olivaceus ) gill cell line as in vitro acute assay system of nonylphenol cytotoxicity  

Microsoft Academic Search

A cell line (FG cells) derived from a gill of the flounder, Paralichthys olivaceus were used to determine the cytotoxic effects of nonylphenol (NP). Cytotoxicity was measured by three endpoint systems: neutral\\u000a red (NR) uptake assay, methyl thiazolyl tetrazolium (MTT) assay and cell protein assay. The result showed that NP was cytotoxic\\u000a to FG cells at all tested concentrations, and

Qin Xiao; Daizong Li; Hongying Liu

2011-01-01

392

Application of Colorimetric Assays to Assess Viability, Growth and Metabolism of Hydrogel-Encapsulated Cells  

Microsoft Academic Search

The applicability of the colorimetric 3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays to measure cell growth and viability in hydrogel encapsulation systems was investigated using HepG2 liver cells encapsulated in alginate matrices. The MTT assay was effective in measuring viable cell density in alginate-encapsulated cell systems, demonstrating less variance and higher throughput capability than hemocytometry. The LDH assay was

Sarwat F. Khattak; Michelle Spatara; Louis Roberts; Susan C. Roberts

2006-01-01

393

Cell identification in primary cell cultures from skin  

Microsoft Academic Search

Summary  Primary cell cultures can readily be obtained from human skin using the explant method. With special care it is possible to\\u000a obtain primary cultures consisting of epidermal keratinocytes without fibroblast contamination. By means of differences in\\u000a their growth patterns and retention of specific differentiative functions in vitro, keratinocytes and fibroblasts can easily\\u000a be distinguished. The high degree of confidence in

B. Allen Flaxman

1974-01-01

394

Establishment and assessment of a new human embryonic stem cell-based biomarker assay for developmental toxicity screening.  

PubMed

A metabolic biomarker-based in vitro assay utilizing human embryonic stem (hES) cells was developed to identify the concentration of test compounds that perturbs cellular metabolism in a manner indicative of teratogenicity. This assay is designed to aid the early discovery-phase detection of potential human developmental toxicants. In this study, metabolomic data from hES cell culture media were used to assess potential biomarkers for development of a rapid in vitro teratogenicity assay. hES cells were treated with pharmaceuticals of known human teratogenicity at a concentration equivalent to their published human peak therapeutic plasma concentration. Two metabolite biomarkers (ornithine and cystine) were identified as indicators of developmental toxicity. A targeted exposure-based biomarker assay using these metabolites, along with a cytotoxicity endpoint, was then developed using a 9-point dose-response curve. The predictivity of the new assay was evaluated using a separate set of test compounds. To illustrate how the assay could be applied to compounds of unknown potential for developmental toxicity, an additional 10 compounds were evaluated that do not have data on human exposure during pregnancy, but have shown positive results in animal developmental toxicity studies. The new assay identified the potential developmental toxicants in the test set with 77% accuracy (57% sensitivity, 100% specificity). The assay had a high concordance (?75%) with existing in vivo models, demonstrating that the new assay can predict the developmental toxicity potential of new compounds as part of discovery phase testing and provide a signal as to the likely outcome of required in vivo tests. PMID:24123775

Palmer, Jessica A; Smith, Alan M; Egnash, Laura A; Conard, Kevin R; West, Paul R; Burrier, Robert E; Donley, Elizabeth L R; Kirchner, Fred R

2013-10-03

395

Scalable expansion of human pluripotent stem cells in suspension culture  

Microsoft Academic Search

Routine commercial and clinical applications of human pluripotent stem cells (hPSCs) and their progenies will require increasing cell quantities that cannot be provided by conventional adherent culture technologies. Here we describe a straightforward culture protocol for the expansion of undifferentiated human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) in suspension culture. This culture technique was successfully tested

Ruth Olmer; Harmeet Singh; Axel Haverich; Robert Zweigerdt; Ulrich Martin

2011-01-01

396

Cell cultures in microsystems: biocompatibility aspects.  

PubMed

Bio-Micro-Electro-Mechanical Systems (BioMEMS) are a new tool in life sciences, supporting cell biology research by providing reproducible and miniaturized experimental platforms. In order to cultivate cells in such systems, appropriate microenvironmental conditions are required. Due to the multitude and variety of microbioreactors and cultivated cell types available, standardized cell handling methods and comprehensive biocompatibility data are sparse. The bioreactor developed at Ilmenau University of Technology features BioMEMS consisting of silicon, glass, and polymers, supplied by peripheral components. To verify the system's suitability for cell cultivation, it was necessary to prove whether materials and surfaces are biocompatible. Custom-tailored biocompatibility test procedures along with adequate cell seeding and handling methods had to be developed. According to this, proper positive and negative control samples had to be identified. The cultivation procedures were carried out using osteoblast-like murine fibroblasts (MC3T3-E1) and primary human osteoblasts (hOB). We could provide evidence that cultivation of these cells in our BioMEMS is feasible. In this context the relevant materials and the system's structure can be regarded as to be biocompatible. We could show that cell seeding and handling methods possess a strong impact on growth, development, and cellular activity of cell cultures in BioMEMS. Statistical biocompatibility data for the materials used is given. PMID:20872818

Fischer, R; Steinert, S; Fröber, U; Voges, D; Stubenrauch, M; Hofmann, G O; Witte, H

2010-11-30

397

Suppressor cells assayed by numerical and functional tests in chronic renal failure  

Microsoft Academic Search

Suppressor cells assayed by numerical and functional tests in chronic renal failure. Suppressor cells were assayed by numerical and functional tests in adults on chronic hemodialysis. Peripheral blood mononuclears (PBM) were classified as total T-cells by E-rosettes and by the monoclonal antibody OKT3, as T-cell subsets by OKT4 (inducer\\/helper T-cells) and OKT8 (cytotoxic\\/suppressor T-cells) and as B-cells by the presence

Jennifer E Lortan; Photini Kiepiela; Hoosen M Coovadia; Yackoob K Seedat

1982-01-01

398

The use of chicken tracheal organ cultures for the isolation and assay of avian infectious bronchitis virus  

Microsoft Academic Search

Summary A study has been made of the use of chicken tracheal organ cultures for the isolation and assay of avian infectious bronchitis (AIB) virus from both naturally and experimentally infected chickens. Six strains of AIB virus were investigated, 3 of which had been isolated from natural outbreaks of disease. Two of the virus isolations from the outbreaks of AIB

Jane K. A. Cook; J. H. Darbyshire; R. W. Peters

1976-01-01

399

A Fluid Membrane-Based Soluble Ligand Display System for Live CellAssays  

SciTech Connect

Cell communication modulates numerous biological processes including proliferation, apoptosis, motility, invasion and differentiation. Correspondingly, there has been significant interest in the development of surface display strategies for the presentation of signaling molecules to living cells. This effort has primarily focused on naturally surface-bound ligands, such as extracellular matrix components and cell membranes. Soluble ligands (e.g. growth factors and cytokines) play an important role in intercellular communications, and their display in a surface-bound format would be of great utility in the design of array-based live cell assays. Recently, several cell microarray systems that display cDNA, RNAi, or small molecules in a surface array format were proven to be useful in accelerating high-throughput functional genetic studies and screening therapeutic agents. These surface display methods provide a flexible platform for the systematic, combinatorial investigation of genes and small molecules affecting cellular processes and phenotypes of interest. In an analogous sense, it would be an important advance if one could display soluble signaling ligands in a surface assay format that allows for systematic, patterned presentation of soluble ligands to live cells. Such a technique would make it possible to examine cellular phenotypes of interest in a parallel format with soluble signaling ligands as one of the display parameters. Herein we report a ligand-modified fluid supported lipid bilayer (SLB) assay system that can be used to functionally display soluble ligands to cells in situ (Figure 1A). By displaying soluble ligands on a SLB surface, both solution behavior (the ability to become locally enriched by reaction-diffusion processes) and solid behavior (the ability to control the spatial location of the ligands in an open system) could be combined. The method reported herein benefits from the naturally fluid state of the supported membrane, which allows surface-linked ligands to diffuse freely in two dimensions. Ligands can become reorganized beneath cells, by reaction-diffusion processes, and may also adopt spatial configurations reflecting those of their cognate receptors on the cell surface (Figure 1B). This provides a significant benefit over conventional cell signaling and culturing systems that present inflexible distributions of signaling molecules. In this study, we observe marked differences in the response of cells to membrane surface displayed soluble ligands as a function of membrane fluidity. Tethering of soluble signaling molecules to fluid supported membranes opens up opportunities to use already developed membrane fabrication technologies to present soluble components within a surface array format.

Nam, Jwa-Min; Nair, Pradeep N.; Neve, Richard M.; Gray, Joe W.; Groves, Jay T.

2005-10-14

400

Isolation and culture of term human cytotrophoblast cells and in vitro methods for studying human cytotrophoblast cells' calcium uptake.  

PubMed

Human primary cytotrophoblast cell culture is a very useful model to study the endocrine and immunological functions of syncytiotrophoblasts, as well as the ion exchange between the mother and her fetus, like calcium. In this chapter, we expose the procedure to (1) isolate and purify the cytotrophoblast cells from human term placenta and (2) study syncytiotrophoblast calcium uptake. First, the methodology is based on the enzymatic dissociation of villous placental tissue, followed by Percoll gradient separation. Purity is assessed by flow cytometry using staining against cytokeratin-7, protein specific for trophoblast cells. Cell proliferation is evaluated by a Thiazolyl Blue Tetrazolium Bromide (MTT) assay, hormonal secretion is measured by enzyme-linked immunosorbent assay (ELISA), and fusion is estimated by immunofluorescence using staining against desmosomal proteins. Second, we describe the calcium uptake experiment using the cytotrophoblast cells in culture. PMID:19495697

Le Bellego, Frédérique; Vaillancourt, Cathy; Lafond, Julie

2009-01-01

401

High-throughput RNA interference screens in Drosophila tissue culture cells.  

PubMed

This chapter describes the method used to conduct high-throughput screening (HTs) by RNA interference in Drosophila tissue culture cells. It covers four main topics: (1) a brief description of the existing platforms to conduct RNAi-screens in cell-based assays; (2) a table of the Drosophila cell lines available for these screens and a brief mention of the need to establish other cell lines as well as cultures of primary cells; (3) a discussion of the considerations and protocols involved in establishing assays suitable for HTS in a 384-well format; and (A) a summary of the various ways of handling raw data from an ongoing screen, with special emphasis on how to apply normalization for experimental variation and statistical filters to sort out noise from signals. PMID:15644175

Armknecht, Susan; Boutros, Michael; Kiger, Amy; Nybakken, Kent; Mathey-Prevot, Bernard; Perrimon, Norbert

2005-01-01

402

A high sensitivity RT-PCR assay for the diagnosis of grapevine viroids in field and tissue culture samples.  

PubMed

An RNA extraction procedure, modified from published methods, and a high sensitivity reverse transcription-polymerase chain reaction (RT-PCR) assay have been developed for the detection of the five viroids in grapevines. All five viroids have been found in the 10 different grape varieties tested so far. This assay, specially optimised for viroids in low copy number by careful selection of DNA primers, has been used in conjunction with dot blot hybridization assay for the study of viroids in vines regenerated by shoot apical meristem culture (SAMC) and fragmented shoot apex culture (FSAC). The data indicate a differential reduction of viroids, rather than viroid elimination, in the regenerated vines. Transmission of viroids via grape seeds was also observed. PMID:9015276

Wan Chow Wah, Y F; Symons, R H

1997-01-01

403

An Introductory Undergraduate Course Covering Animal Cell Culture Techniques  

ERIC Educational Resources Information Center

|Animal cell culture is a core laboratory technique in many molecular biology, developmental biology, and biotechnology laboratories. Cell culture is a relatively old technique that has been sparingly taught at the undergraduate level. The traditional methodology for acquiring cell culture training has been through trial and error, instruction…

Mozdziak, Paul E.; Petitte, James N.; Carson, Susan D.

2004-01-01

404

Cell culture: Progenitor cells from human brain after death  

NASA Astrophysics Data System (ADS)

Culturing neural progenitor cells from the adult rodent brain has become routine and is also possible from human fetal tissue, but expansion of these cells from postnatal and adult human tissue, although preferred for ethical reasons, has encountered problems. Here we describe the isolation and successful propagation of neural progenitor cells from human postmortem tissues and surgical specimens. Although the relative therapeutic merits of adult and fetal progenitor cells still need to be assessed, our results may extend the application of these progenitor cells in the treatment of neurodegenerative diseases.

Palmer, Theo D.; Schwartz, Philip H.; Taupin, Philippe; Kaspar, Brian; Stein, Stuart A.; Gage, Fred H.

2001-05-01

405

A noninvasive cell-based assay for monitoring proteolytic activity within a specific subcellular compartment.  

PubMed

A noninvasive cell-based assay has been developed to monitor the proteolytic activity of cathepsin L within a specific subcellular compartment, the lysosome. The green fluorescent protein (GFP) of Aequorea victoria was selected as a substrate. Targeting to lysosomes was achieved by fusing GFP to preprocathepsin L, which also ensures colocalization of the enzyme and the substrate. Stably transfected HeLa-rtTA (reverse tetracycline-controlled transactivator) cells were induced with doxycycline and cultured in the presence of various concentrations of cysteine protease inhibitors for 48 h. In the absence of inhibitor, proteolytic degradation of GFP leads to loss of fluorescence, which is due almost exclusively to the action of recombinant cathepsin L. However, a dose-dependent increase of GFP fluorescence is observed for cells treated with the potent cathepsin L inhibitor benzyloxycarbonyl-LeuLeuTyr-CHN(2). Fluorescence is also observed when GFP is fused to an inactive preprocathepsin L (C25A mutant). Targeting of GFP to an acidic cellular compartment can destabilize the protein and render it susceptible to proteolytic degradation. The approach should be generally applicable for proteases localized in acidic environments. Such an assay can be of great value in validating the participation of a specific enzyme in a given process or in testing the ability of putative inhibitors to reach their intracellular target. PMID:12123661

Belkhiri, Abbes; Lytvyn, Viktoria; Guilbault, Claire; Bourget, Lucie; Massie, Bernard; Nägler, Dorit K; Ménard, Robert

2002-07-15

406

Assay validation for the assessment of adipogenesis of multipotential stromal cells--a direct comparison of four different methods  

PubMed Central

Background aims Mesenchymal stromal cells (MSCs) are regenerative and immuno-privileged cells that are used for both tissue regeneration and treatment of severe inflammation-related disease. For quality control of manufactured MSC batches in regard to mature fat cell contamination, a quantitative method for measuring adipogenesis is needed. Methods Four previously proposed methods were validated with the use of bone marrow (BM) MSCs during a 21-day in vitro assay. Oil red staining was scored semiquantitatively; peroxisome proliferator activated receptor-? and fatty acid binding protein (FABP)4 transcripts were measured by quantitative real-time polymerase chain reaction; FABP4 protein accumulation was evaluated by flow cytometry; and Nile red/4?,6-diamidino-2-phenylindole (DAPI) ratios were measured in fluorescent microplate assay. Skin fibroblasts and MSCs from fat pad, cartilage and umbilical cord were used as controls. Results Oil red staining indicated considerable heterogeneity between BM donors and individual cells within the same culture. FABP4 transcript levels increased 100- to 5000-fold by day 21, with large donor variability observed. Flow cytometry revealed increasing intra-culture heterogeneity over time; more granular cells accumulated more FABP4 protein and Nile red fluorescence compared with less granular cells. Nile red increase in day-21 MSCs was ?5- and 4-fold, measured by flow cytometry or microplate assay, respectively. MSC proliferation/apoptosis was accounted through the use of Nile red/DAPI ratios; adipogenesis levels in day-21 BM MSCs increased ?13-fold, with significant correlations with oil red scoring observed for MSC from other sources. Conclusions Flow cytometry permits the study of MSC differentiation at the single-cell level and sorting more and less mature cells from mixed cell populations. The microplate assay with the use of the Nile red/DAPI ratio provides rapid quantitative measurements and could be used as a low-cost, high-throughput method to quality-control MSC batches from different tissue sources.

Aldridge, Andrew; Kouroupis, Dimitrios; Churchman, Sarah; English, Anne; Ingham, Eileen; Jones, Elena

2013-01-01

407

A rapid and sensitive method for measuring N-acetylglucosaminidase activity in cultured cells.  

PubMed

A rapid and sensitive method to quantitatively assess N-acetylglucosaminidase (NAG) activity in cultured cells is highly desirable for both basic research and clinical studies. NAG activity is deficient in cells from patients with Mucopolysaccharidosis type IIIB (MPS IIIB) due to mutations in NAGLU, the gene that encodes NAG. Currently available techniques for measuring NAG activity in patient-derived cell lines include chromogenic and fluorogenic assays and provide a biochemical method for the diagnosis of MPS IIIB. However, standard protocols require large amounts of cells, cell disruption by sonication or freeze-thawing, and normalization to the cellular protein content, resulting in an error-prone procedure that is material- and time-consuming and that produces highly variable results. Here we report a new procedure for measuring NAG activity in cultured cells. This procedure is based on the use of the fluorogenic NAG substrate, 4-Methylumbelliferyl-2-acetamido-2-deoxy-alpha-D-glucopyranoside (MUG), in a one-step cell assay that does not require cell disruption or post-assay normalization and that employs a low number of cells in 96-well plate format. We show that the NAG one-step cell assay greatly discriminates between wild-type and MPS IIIB patient-derived fibroblasts, thus providing a rapid method for the detection of deficiencies in NAG activity. We also show that the assay is sensitive to changes in NAG activity due to increases in NAGLU expression achieved by either overexpressing the transcription factor EB (TFEB), a master regulator of lysosomal function, or by inducing TFEB activation chemically. Because of its small format, rapidity, sensitivity and reproducibility, the NAG one-step cell assay is suitable for multiple procedures, including the high-throughput screening of chemical libraries to identify modulators of NAG expression, folding and activity, and the investigation of candidate molecules and constructs for applications in enzyme replacement therapy, gene therapy, and combination therapies. PMID:23840811

Mauri, Victor; Lotfi, Parisa; Segatori, Laura; Sardiello, Marco

2013-06-28

408

Artifacts by marker enzyme adsorption on nanomaterials in cytotoxicity assays with tissue cultures  

NASA Astrophysics Data System (ADS)

We used precision cut lung slices (PCLS) to study the cytotoxicity of cobalt ferrite nanomaterials with and without bovine serum albumin (BSA) stabilization. Using mitochondrial activity as an indicator of cytotoxicity (WST-1 assay) increasing concentrations of cobalt ferrite nanomaterial caused increasing levels of cytotoxicity in PCLS irrespective of BSA stabilization. However, there was no increase in released lactate dehydrogenase (LDH) levels caused by BSA stabilized nanomaterial indicating concentration depended cytotoxictiy. Moreover, non-stabilized nanomaterial caused a decrease of background LDH levels in the PCLS culture supernatant confirmed by complementary methods. Direct characterization of the protein corona of extracted nanomaterial shows that the LDH decrease is due to adsorption of LDH onto the surface of the non-stabilized nanomaterial, correlated with strong agglomeration. Preincubation with serum protein blocks the adsorption of LDH and stabilizes the nanomaterial at low agglomeration. We have thus demonstrated the cytotoxicity of nanomaterials in PCLS does not correlate with disrupted membrane integrity followed by LDH release. Furthermore, we found that intracellular enzymes such as the marker enzyme LDH are able to bind onto surfaces of nanomaterial and thereby adulterate the detection of toxic effects. A replacement of BSA by LDH or a secondary LDH-on-BSA-corona were not observed, confirming earlier indications that the protein corona exchange rate are slow or vanishing on inorganic nanomaterial. Thus, the method(s) to assess nanomaterial-mediated effects have to be carefully chosen based on the cellular effect and possible nano-specific artifacts.

Wohlleben, Wendel; Kolle, Susanne N.; Hasenkamp, Laura-Carolin; Böser, Alexander; Vogel, Sandra; von Vacano, Bernhard; van Ravenzwaay, Ben; Landsiedel, Robert

2011-07-01

409

Production of avian influenza virus vaccine using primary cell cultures generated from host organs.  

PubMed

The global availability of a therapeutically effective influenza virus vaccine during a pandemic remains a major challenge for the biopharmaceutical industry. Long production time, coupled with decreased supply of embryonated chicken eggs (ECE), significantly affects the conventional vaccine production. Transformed cell lines have attained regulatory approvals for vaccine production. Based on the fact that the avian influenza virus would infect the cells derived from its natural host, the viral growth characteristics were studied on chicken embryo-derived primary cell cultures. The viral propagation was determined on avian origin primary cell cultures, transformed mammalian cell lines, and in ECE. A comparison was made between these systems by utilizing various cell culture-based assays. In-vitro substrate susceptibility and viral infection characteristics were evaluated by performing hemagglutination assay (HA), 50 % tissue culture infectious dose (TCID??) and monitoring of cytopathic effects (CPE) caused by the virus. The primary cell culture developed from chicken embryos showed stable growth characteristics with no contamination. HA, TCID??, and CPE exhibited that these cell systems were permissive to viral infection, yielding 2-10 times higher viral titer as compared to mammalian cell lines. Though the viral output from the ECE was equivalent to the chicken cell culture, the time period for achieving it was decreased to half. Some of the prerequisites of inactivated influenza virus vaccine production include generation of higher vial titer, independence from exogenous sources, and decrease in the production time lines. Based on the tests, it can be concluded that chicken embryo primary cell culture addresses these issues and can serve as a potential alternative for influenza virus vaccine production. PMID:23515853

Babar, Mustafeez Mujtaba; Riaz, Muhammad Suleman; Zaidi, Najam-us-Sahar Sadaf; Afzal, Farhan; Farooq, Muhammad Sabir

2013-03-21

410

A high-throughput three-dimensional cell migration assay for toxicity screening with mobile device-based macroscopic image analysis  

PubMed Central

There is a growing demand for in vitro assays for toxicity screening in three-dimensional (3D) environments. In this study, 3D cell culture using magnetic levitation was used to create an assay in which cells were patterned into 3D rings that close over time. The rate of closure was determined from time-lapse images taken with a mobile device and related to drug concentration. Rings of human embryonic kidney cells (HEK293) and tracheal smooth muscle cells (SMCs) were tested with ibuprofen and sodium dodecyl sulfate (SDS). Ring closure correlated with the viability and migration of cells in two dimensions (2D). Images taken using a mobile device were similar in analysis to images taken with a microscope. Ring closure may serve as a promising label-free and quantitative assay for high-throughput in vivo toxicity in 3D cultures.

Timm, David M.; Chen, Jianbo; Sing, David; Gage, Jacob A.; Haisler, William L.; Neeley, Shane K.; Raphael, Robert M.; Dehghani, Mehdi; Rosenblatt, Kevin P.; Killian, T. C.; Tseng, Hubert; Souza, Glauco R.

2013-01-01

411

A high-throughput three-dimensional cell migration assay for toxicity screening with mobile device-based macroscopic image analysis  

NASA Astrophysics Data System (ADS)

There is a growing demand for in vitro assays for toxicity screening in three-dimensional (3D) environments. In this study, 3D cell culture using magnetic levitation was used to create an assay in which cells were patterned into 3D rings that close over time. The rate of closure was determined from time-lapse images taken with a mobile device and related to drug concentration. Rings of human embryonic kidney cells (HEK293) and tracheal smooth muscle cells (SMCs) were tested with ibuprofen and sodium dodecyl sulfate (SDS). Ring closure correlated with the viability and migration of cells in two dimensions (2D). Images taken using a mobile device were similar in analysis to images taken with a microscope. Ring closure may serve as a promising label-free and quantitative assay for high-throughput in vivo toxicity in 3D cultures.

Timm, David M.; Chen, Jianbo; Sing, David; Gage, Jacob A.; Haisler, William L.; Neeley, Shane K.; Raphael, Robert M.; Dehghani, Mehdi; Rosenblatt, Kevin P.; Killian, T. C.; Tseng, Hubert; Souza, Glauco R.

2013-10-01