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At least 145 records · Page 8Linked to original sources
PubMed2000

Cell viability and growth in a battery of human breast cancer cell lines exposed to 60 Hz magnetic fields.

Epidemiological data suggest that exposure to power-frequency (50/60 Hz) magnetic fields (MFs) may be a risk factor for breast cancer in humans. To determine whether MFs affect human breast cancer cells, we measured viability, growth and cytotoxicity in a battery of breast cancer cell lines after in vitro MF and sham exposure. Cells of three estrogen receptor-positive human breast cancer cell lines (MCF-7, ZR-75-1 and T-47D) and one estrogen receptor-negative human breast cancer cell line (MDA-MB-231) and normal (nontransformed) human breast epithelial cells were exposed to MFs (1 mT) or sham fields (<0.0001 mT) for 72 h. Cell viability was determined using the sulforhodamine B (SRB) assay at 0 and 72 h after the MF exposure period. Cell growth was measured as the change in SRB dye uptake over 72 h after MF exposure. MF exposure had no effect on cell viability or growth in any cell type examined. Similarly, MF exposure had no effect on cytotoxicity induced by exposure to the retinoid N-(4-hydroxyphenyl)retinamide. These data do not support the hypothesis that MF exposure stimulates growth of breast cancer cells.

Apoptosis↗
PubMed2005

A novel method for the assessment of cellular composition and beta-cell viability in human islet preparations.

Current methodologies to evaluate islet cell viability are largely based on tests that assess the exclusion of DNA-binding dyes. While these tests identify cells that have lost selective membrane permeability, they do not allow us to recognize apoptotic cells, which do not yet stain with DNA-binding dyes. Furthermore, current methods of analysis do not discriminate between cell subsets in the preparation and, in particular, they do not allow for selectively defining beta-cell viability. For these reasons we have developed novel methods for the specific assessment of beta-cell content and viability in human islets based on cellular composition analysis through laser scanning cytometry (LSC) coupled with identification of beta-cell-specific apoptosis at the mitochondrial level. Our novel analytical methods hold promise to prospectively analyze clinical islet transplantation preparations and predict functional performance, as suggested by the observed correlation with in vivo analysis of islet potency in immunodeficient rodents.

Apoptosis↗
PubMed1998

Effect of soaking in Hank's balanced salt solution or milk on PDL cell viability of dry stored human teeth.

This study was designed to evaluate the effect of soaking in either Hank's balanced salt solution (HBSS) or milk on periodontal ligament (PDL) cell viability in avulsed teeth. Dry storage times of 30, 60, and 90 min were evaluated. PDL cell viability was determined after removal of the cells from the root surfaces of extracted teeth using a modification of the procedure described by Nakashima (Arch Oral Biol 1991;36:655-63). After trypsinization and subsequent treatment in collagenase, the cells were stained with trypan blue, and viable and non-viable cells were counted using a hemocytometer and converted to percentages for statistical comparison. The results of this study demonstrated no significant difference in the number of viable cells with or without soaking in HBSS or milk at any of the dry storage times. In addition, there was no significant difference in PDL cell viability between the 30-and the 60-min dry periods. Although the soaking procedure had no obvious negative consequence, no significant improvement in PDL cell viability by the addition of this step was demonstrated under the conditions of this study.

Adolescent↗
PubMed2002

Detachment of glycolytic enzymes from cytoskeleton of Lewis lung carcinoma and colon adenocarcinoma cells induced by clotrimazole and its correlation to cell viability and morphology.

Cancer cells are characterized by a high rate of glycolysis, which is their primary energy source. Glycolysis is known to be controlled by allosteric regulators, as well as by reversible binding of glycolytic enzymes to cytoskeleton. We report here that clotrimazole (l-(alpha-2-chlorotrityl)imidazole), the antifungal azole derivative, which was recently recognized as calmodulin antagonist, induced a dose-dependent detachment of the glycolytic enzymes, phosphofructokinase (ATP: D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) and aldolase (D-fructose-l,6-bisphosphate D-glyceraldehyde-3-phosphate-lyase, EC 4.1.2.13), from cytoskeleton of LL/2 Lewis lung carcinoma cells and CT-26 colon adenocarcinoma cells. The detachment of glycolytic enzymes from cytoskeleton would reduce the provision of local ATP, in the vicinity of the cytoskeleton membrane, and would also affect cytoskeleton structure and cell shape. We show here that clotrimazole decreased the viability of LL/2 Lewis lung carcinoma cells and CT-26 colon adenocarcinoma cells. After 3h of incubation with clotrimazole, complete cell destruction was detected. Ultrastructural cell damage was manifested by disintegration of the outer membrane by scanning electron microscopy (SEM). The detachment of glycolytic enzymes from cytoskeleton, induced by clotrimazole, preceded the decrease in cell viability, which indicates that this is an early effect and not a result of cell death. Since the cytoskeleton is being recognized as an important modulator of cell function, proliferation, differentiation, and neoplasia, detachment of the glycolytic enzymes from cytoskeleton induced by clotrimazole, as well as its reported inhibitory action on cell proliferation, makes this drug the most promising agent in the treatment of cancer.

Adenocarcinoma↗
PubMed2003

Increased p53 levels without caspase-3 activity and change of cell viability in 6-hydroxydopamine-treated CV1-P cells.

The effect of 6-hydroxydopamine (6-OHDA) on the level of p53 protein, the activity of caspase-3 and the nuclear morphology-based assessment of cell viability were compared in the nonneuronal CV1-P fibroblast and neuronal SH-SY5Y neuroblastoma cells. The level of p53 protein was increased in the low-dose range (<100 micromol/L) in both cell types, particularly in fibroblasts. In the neuroblastoma cells, a moderate p53 increase paralleled the elevated caspase-3 activity and apoptotic cell behavior. Interestingly, in the fibroblasts at the low 6-OHDA concentrations, p53 remained high during the whole experiment, and there was neither significant caspase-3 activity nor cell death. In the high-dose range (>100 micromol/L), the increase of p53 was reduced and the cell death was predominantly necrotic as judged from the nuclear morphology in both fibroblasts and neuroblastoma cells. Also, the caspase-3 activity was reduced in SH-SY5Y cells. In contrast to some earlier reports, we have shown that the actual 6-OHDA sensitivity of nonneuronal cells may be equal or even higher than that in neuronal cells if the enhancement of p53 levels is used as a criterion for the response. However, the 6-OHDA toxicity was clearly higher in the neuronal than in fibroblast cells.

Animals↗
PubMed1987

Assessment of islet cell viability using fluorescent dyes.

A rapid fluorometric method has been developed to evaluate the viability of isolated islet cells. The assay differentiates between viable and nonviable cells by the simultaneous use of the inclusion and exclusion dyes acridine orange and propidium iodide. When viewed by fluorescent microscopy, viable cells fluoresce green, while nonviable cells fluoresce bright red. Although the acridine orange and propidium iodide assay measures membrane integrity, the results of this assay correlate with other measures of cell viability. Compared to trypan blue exclusion, this assay is easier to read, more stable, and has fewer staining artifacts. The assay enables the rapid estimation of the viability of a population of islet cells prior to time-consuming experiments rather than retrospectively. This assay can also be used with intact islets. Stained islets can be divided into three distinct groups: green fluorescing islets contain insulin, red fluorescing islets contain little or no insulin and a third class of islets containing some non-viable cells fluoresce red, green, and yellow. The yellow colour is due to the superimposition of red and green fluorescing cells.

Acridine Orange↗
PubMed2003

Progesterone as a regulator of granulosa cell viability.

Progesterone (P4) prevents numerous cells, including uterine, mammary and ovarian cells, from undergoing apoptosis. Interestingly, P4 prevents apoptosis of ovarian granulosa cells (GCs), which do not express the classic nuclear P4 receptor. This review presents data that support a non-genomic action of P4 in granulosa cells. These studies were conducted using both primary rat granulosa cells and rat spontaneously immortalized granulosa cells (SIGCs). Specifically, these studies reveal that (1) 3H-P4 specifically binds to SIGCs; (2) an antibody directed against the ligand binding domain of the nuclear P4 receptor (C-262) detects a 60kDa protein, which localizes to the plasma membrane and binds P4; and (3) treatment with C-262 blocks P4's ability to maintain granulosa cell viability. Additional studies demonstrate that a protein kinase G (PKG) activator, 8-br-cGMP, mimics and PKG antagonists, Rp-8-pcCPT-GMP and KT5823, attenuate P4's action. These studies support the concept that the 60kDa P4 binding protein functions as membrane receptor for P4 which activates a PKG-dependent mechanism to regulate granulosa cell survival.

Apoptosis↗
PubMed1993

Application of the adenosine triphosphate-cell viability assay in human breast cancer chemosensitivity testing: a report on the first results.

Chemosensitivity testing in vitro of breast cancer has been difficult because of small tumour volume, an even smaller yield of viable cells after disaggregation, and the low evaluability rate and sensitivity of current assays. We have employed an alternative approach that quantitates intracellular adenosine triphosphate (ATP) as a measure of cell viability. This ATP-cell viability assay (ATP-CVA) determines in vitro tumor cell viability after exposure to chemotherapeutic agents in comparison to untreated controls following 6 days of incubation. Sixty-one fresh breast cancer specimens upon testing yielded an evaluability rate of 95%. Forty-seven of the tumors were untreated primary breast cancers, the remaining 14 were from patients with metastatic disease. Correlations of in vitro drug sensitivity with in vivo response were obtained for 17 treatment regimens in 14 patients with metastatic breast cancer. The level of sensitivity was 90% and the specificity 86%. These preliminary data demonstrated the ATP-CVA to be a practical in vitro approach to breast cancer testing. It will require a larger clinical study for confirmation.

Adenosine Triphosphate↗
PubMedDate not supplied

Use of fluorescent probes for determination of yeast cell viability by gravitational field-flow fractionation.

The quality of wine greatly depends on the features of the yeast used in its production, and yeast cell viability is one of the most important quality control issues to consider in this regard. In the first steps of winemaking, the use of a low-cost and simple methodology for monitoring the cell viability of yeast inoculates is of paramount importance. Gravitational field-flow fractionation is a useful technique for the determination of cell viability because it provides gentle experimental conditions, although the proper use of fluorophore probes as biomass indicators is required. In this paper the use of different fluorescent probes such as carboxyfluorescein diacetate (cFDA), calcein-AM, and SYTO-13 were considered as viability biomarkers. Calceina-AM allowed the establishment of a direct GrFFF method to determine cell viability, with a limit of detection of 5.0 x 10(4) viable cell/mL. SYTO-13 could be used as biomass indicator with a limit of detection of 3.5 x 10(4) total cells/mL. The suitability of the procedure was tested with three commercial yeast samples, and the results were compared with those obtained using standard techniques.

Calibration↗
PubMed2004

Comparison of cell viability on anorganic bone matrix with or without P-15 cell binding peptide.

Cell-extracellular cell matrix (ECM) interactions play a vital role in development including cytoskeletal structure, growth and differentiation. A 15 amino acid, non-RGD containing, peptide that is derived from type I collagen was tested for its ability to confer cell survival. Two routinely utilized bone graft materials, anorganic bone matrix (ABM) and ABM carrying the cell binding peptide P-15 were compared for cell viability and apoptosis. Anchorage-dependent human foreskin fibroblasts (HFF) or osteogenic MC3T3-E1 cells were seeded on ABM or ABM/P-15. After serum withdrawal, viability and level of apoptosis were significantly (p<0.05) improved for cells on ABM/P-15 compared to cells on ABM. Scanning electron microscopy confirmed large, spread cells on ABM/P-15 and smaller cells with apoptotic cellular blebs on ABM. In addition, viable cell attachment was significantly greater on cells cultured on ABM/P-15 compared with demineralized freeze-dried bone allograft. This is the first report that the P-15 cell binding peptide, when complexed with ABM, promotes cell survival. The P-15 peptide may modulate cell number and tissue structure by the enhancement of viable cell attachment and via the regulation of apoptosis.

3T3 Cells↗
PubMed2004

Modeling mass transfer in hepatocyte spheroids via cell viability, spheroid size, and hepatocellular functions.

Hepatocyte aggregation into spheroids attributes to their increased activity, but in the absence of a vascular network the cells in large spheroids experience mass transfer limitations. Thus, there is a need to define the spheroid size which enables maximal cell viability and productivity. We developed a combined theoretical and experimental approach to define this optimal spheroid size. Hepatocyte spheroids were formed in alginate scaffolds having a pore diameter of 100 microm, in rotating T-flasks or spinners, to yield a maximal size of 100, 200, and 600 microm, respectively. Cell viability was found to decrease with increasing spheroid size. A mathematical model was constructed to describe the relationship between spheroid size and cell viability via the oxygen mass balance equation. This enabled the prediction of oxygen distribution profiles and distribution of viable cells in spheroids with varying size. The model describes that no oxygen limitation will take place in spheroids up to 100 microm in diameter. Spheroid size affected the specific rate of albumin secretion as well; it reached a maximal level, i.e., 60 microg/million cells/day in 100-microm diameter spheroids. This behavior was depicted in an equation relating the specific albumin secretion rate to spheroid size. The calculated results fitted with the experimental data, predicting the need for a critical number of viable hepatocytes to gain a maximal albumin secretion. Taken together, the results on mass transport in spheroids and its effects on cell viability and productivity provide a useful tool for the design of 3D scaffolds with pore diameters of 100 microm.

Albumins↗
PubMedDate not supplied

Protective effect of endothelin antagonist (TAK-044) on neuronal cell viability in in vitro oxygen-glucose deprivation model of stroke.

The present study was carried to investigate the effect of endothelin antagonist (TAK-044) in an in vitro model of stroke using primary neuronal culture. Hypoxia in neuronal culture was induced for 3 h using oxygen glucose deprivation (OGD) model, thereafter cells were reperfused. In separate group cultures were incubated with graded concentrations of TAK-044 (0.01, 0.1 and 1 microg/microl) for different time duration i.e. 6, 12 and 24 hours after reperfusion. Percent cell viability was assessed 24 h after reperfusion using MTT assay. It was observed that percent cell viability was reduced to 13.7 +/- 0.4% in the cells under 3 h hypoxic condition as compared to the cells under normal condition (100%). TAK-044 at the concentrations of 0.1 and 1 microg/microl, but not at 0.01 microg/microl showed significant (P<0.01) improvement in the % cell viability as compared to the cells in hypoxic condition. Percent cell viability at the concentration of 0.1 and 1 microg/microl for 24 h time duration after reperfusion were 54.8 +/- 3.2% and 75.4 +/- 1.8% respectively as compared to the cells under hypoxic condition (13.7 +/- 0.4%). The results demonstrate the neuroprotective effect of TAK-044 against neuronal damage caused by hypoxia induced in neuronal culture.

Animals↗
PubMed1991

Endothelial cell viability in the rat aortic wall.

Aortic allografts may offer advantages over prosthetic materials for aortic valve replacement or reconstruction with a valved aortic conduit. Cellular viability may partly determine long-term allograft performance. To evaluate endothelial cell viability in a rat model, valved aortic conduits were subjected to collagenase digestion. The resulting endothelial cell suspension was labeled with Griffonia simplicifolia agglutinin-fluorescein isothiocyanate (GSA-FITC), a marker specific for vascular endothelial cells of the rat. The cells were then incubated with propidium iodide, which is excluded by viable cells. Flow cytometry evaluated endothelial cell viability by determination of percentage of GSA-FITC-positive cells that were negative for propidium iodide. Aortas were studied immediately after harvest or after storage at 4 degrees C in a nutrient medium for 3 to 21 days. Percentage of viable endothelial cells showed a progressive decline with increasing duration of storage. These results demonstrate flow cytometric measurement of endothelial cell viability, a factor of possible importance in assessing allograft storage methods, and show that endothelial viability declines with prolonged storage at 4 degrees C in a nutrient medium.

Animals↗
PubMed1997

Cytochemical studies of cell viability and gene expression in Bacillus subtilis macrofibres.

The viability of cells and the expression of a reporter gene in Bacillus subtilis macrofibres have been examined using cytochemical approaches. Previous studies have shown that macrofibres grow at an exponential rate in fluid environments and undergo complex dynamic motions as they elongate but the behaviour of individual cells in them has never been examined. A fluorescence staining procedure that distinguishes living cells from dead cells was used in the experiments described to examine cells in both left- and right-handed macrofibres. Very few dead cells were found in individual fibres. Their locations appeared to be random, suggesting that neither the extreme shape deformation imposed upon cells in the loop ends of fibres, nor the entrapment of cells in the interior of a fibre compromise viability. In related experiments, initial studies of reporter gene expression during fibre morphogenesis were conducted using a strain previously studied as conventional colonies. Spatial and temporal differences in the appearance of the blue cleavage product of X-Gal were found, suggesting that differential gene expression may arise in macrofibres in contrast to the results found in colonies. Two conclusions may be drawn from the findings: (i) virtually all cells in macrofibres are viable and (ii) all the cells in macrofibres do not always behave in an identical manner.

Bacillus subtilis↗
PubMed2000

Determination of periodontal ligament cell viability in long shelf-life milk.

The purpose of this study was to determine the ability of long shelf-life milk to serve as a temporary storage medium for the maintenance of periodontal ligament (PDL) cell viability on avulsed teeth. PDL cells were plated onto 24-well culture plates and allowed to attach for 24 h. Minimal Essential Medium was replaced with regular pasteurized milk (refrigerated milk), long shelf-life milk (Parmalat), or Save-A-Tooth. Tap water served as the negative control, and Minimal Essential Medium served as the positive control. The tissue culture plates were incubated at 37 degrees C for 1, 2, 4, or 8 h. Cell viability was determined using a cell proliferation assay (CellTiter 96 AQ Assay) and absorbance read at 490 nm. ANOVA indicated that all media performed significantly better than tap water at all time periods. At 8 h, PDL cell viability in regular pasteurized milk and long shelf-life milk were significantly greater than in Save-A-Tooth (p < or = 0.001). There was no significant difference between regular pasteurized milk and long shelf-life milk at any time period. These results suggest that long shelf-life milk, which has the advantage of not requiring refrigeration, is as effective a storage medium for avulsed teeth as regular pasteurized milk and more effective than Save-A-Tooth.

Analysis of Variance↗
PubMed1993

[Cell viability assessment of cold-preserved (4 degrees C) and cryopreserved (-196 degrees C) allograft valves by flowcytometric analysis].

We introduced cryopreservation technique to store the allograft valve and subsequently commenced the use of the cryopreserved aortic allograft valve for aortic valve replacement. For the clinical use of the allograft valve, it is essential to evaluate the cell viability. We assessed cell viability of the allograft valve by flowcytometry (FCM), using a fluorescein diacetate (FDA)-propidium iodide (PI) stain. Pulmonary allograft valves were harvested from the cadavers with a consent. Of the 9 valves collected and sterilized in 4 degrees C antibiotic solution for 48 hours, 4 valves were stored under refrigeration (cold-preserved), and the remaining 5 valves were cryopreserved. The warm ischemic time from cardiac death to valve preservation was 7.3 +/- 5.4 hours. The cold-preserved valves were stored at 4 degrees C in the nutrient medium (TC-199, calf serum and HEPES buffer). The cryopreserved valves were frozen by a programmable freezer to -80 degrees C in the same nutrient medium containing 10% dimethylsulfoxide (DMSO), and subsequently stored in liquid nitrogen (-196 degrees C). We assessed the cell viability of the allograft valve leaflet, before storage and at 2 weeks, 1 month and 2 months after the storage. Suspensions of the valve leaflet fibroblasts were double-stained with FDA (1 micrograms/ml) and PI (1 microgram/ml) for flowcytometric analysis of the viable cells (cells showing a chromatic response to FDA but no response to PI). In the cold-preserved group, percentage of the viable cell was 90.3 +/- 3.6% before storage, 62.0 +/- 3.0% after 1 month of storage, and 50.3 +/- 3.7% after 2 months of storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1991

Cytotoxicity of T-2 toxin and its metabolites determined with the neutral red cell viability assay.

The neutral red (NR) cell viability assay was used with various cell types of human origin to quantitate the potency of T-2 mycotoxin and its metabolites. The human melanoma SK-Mel/27 cell line was the most sensitive, with a midpoint cytotoxicity value of 2.8 ng of T-2 per ml. With the human hepatoma cell line, HepG2, the sequence of potency for a series of mycotoxins was T-2 greater than HT-2 greater than T-2 triol greater than T-2 tetraol.

Animal Testing Alternatives↗
PubMed2004

Evidence for differential effects of selective somatostatin receptor subtype agonists on alpha-subunit and chromogranin a secretion and on cell viability in human nonfunctioning pituitary adenomas in vitro.

Somatostatin (SRIF) analogs interacting with SRIF receptor (SSTR) subtypes SSTR2 and SSTR5 reduce hormone secretion of pituitary adenomas, but their antiproliferative effects are still controversial. We investigated the in vitro effects of SRIF and SSTR-selective agonists interacting with SSTR1 (BIM-23926), SSTR2 (BIM-23120), SSTR5 (BIM-23206), or both SSTR2 and SSTR5 (BIM-23244) on alpha-subunit and chromogranin A secretion and on cell viability of 12 nonfunctioning pituitary adenomas (NFA) expressing SSTR1, SSTR2, and SSTR5, as assessed by RT-PCR. Treatment with SRIF or BIM-23206 did not modify alpha-subunit and chromogranin A secretion, which was significantly inhibited by BIM-23926, BIM-23120, and BIM-23244. SRIF and BIM-23120 did not influence cell viability, which was significantly promoted by BIM-23206 and BIM-23244 and reduced by treatment with BIM-23926. These results demonstrate that, in the selected NFA, the SSTR1-selective agonist inhibits secretory activity and cell viability, the SSTR2-selective agonist inhibits secretion but not cell viability, and the SSTR5-selective agonist does not influence secretion but promotes cell viability. These data can explain the lack of inhibitory effects of currently used SRIF analogs and suggest that drugs acting potently and preferentially on SSTR1 might be useful for medical treatment of NFA.

Adenoma↗