Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cell viability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed2004

Cell viability mapping within long-term heart valve organ cultures.

BACKGROUND AND AIM OF THE STUDY: Organ cultures maintain cells within their native microstructural environment, and thus offer greater potential for studying tissue disease and remodeling than do monolayer cell cultures or pathological examinations of diseased tissue. To validate an in-vitro heart valve organ culture model, cell viability was examined within valve tissues over sustained culture periods. METHODS: Following culture of blocks of valve tissue for 1 to 49 days, cross-sections were cut with a vibratome, stained with a LIVE/DEAD kit, and imaged with confocal microscopy to quantify the number of live and dead cells present. RESULTS: In numerous organ cultures, valvular interstitial cells were found to be viable beyond 30 days. Live cells were abundant in the central region of the valve, but more sparse in the deepest central regions. Dead cells were found mainly on the surface of both fresh tissues and tissues after prolonged culture, with few dead cells occurring centrally. CONCLUSION: This is the first reported mapping of cell viability within heart valve organ cultures, and results suggest that extended organ culture of valve leaflets is indeed possible. The derived viability staining methods have wide applicability for organ cultures of other tissues as well as tissue-engineered matrices.

Animals↗
PubMed2006

The role of laser fluence in cell viability, proliferation, and membrane integrity of wounded human skin fibroblasts following helium-neon laser irradiation.

BACKGROUND: In medicine, lasers have been used predominantly for applications, which are broadly termed low level laser therapy (LLLT), phototherapy or photobiomodulation. This study aimed to establish cellular responses to Helium-Neon (632.8 nm) laser irradiation using different laser fluences (0.5, 2.5, 5, 10, and 16 J/cm(2)) with a single exposure on 2 consecutive days on normal and wounded human skin fibroblasts. MATERIALS AND METHODS: Changes in normal and wounded fibroblast cell morphology were evaluated by light microscopy. Changes following laser irradiation were evaluated by assessing the mitochondrial activity using adenosine triphosphate (ATP) luminescence, cell proliferation using neutral red and an alkaline phosphatase (ALP) activity assay, membrane integrity using lactate dehydrogenase (LDH), and percentage cytotoxicity and DNA damage using the Comet assay. RESULTS: Morphologically, wounded cells exposed to 5 J/cm(2) migrate rapidly across the wound margin indicating a stimulatory or positive influence of phototherapy. A dose of 5 J/cm(2) has a stimulatory influence on wounded fibroblasts with an increase in cell proliferation and cell viability without adversely increasing the amount of cellular and molecular damage. Higher doses (10 and 16 J/cm(2)) were characterized by a decrease in cell viability and cell proliferation with a significant amount of damage to the cell membrane and DNA. CONCLUSIONS: Results show that 5 J/cm(2) stimulates mitochondrial activity, which leads to normalization of cell function and ultimately stimulates cell proliferation and migration of wounded fibroblasts to accelerate wound closure. Laser irradiation can modify cellular processes in a dose or fluence (J/cm(2)) dependent manner.

Cell Proliferation↗
PubMed2005

Thermoresponsive polymers as gene delivery vectors: cell viability, DNA transport and transfection studies.

A range of gene delivery vectors containing the thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAm) was evaluated for effects on cell viability, intracellular trafficking and transgene expression in C2C12 mouse muscle cells. Polymers were complexed with plasmid DNA at pH 7.4 and the ability of the resulting particles to transfect cells was assessed via confocal microscopy and protein expression studies in tissue culture. Cell viability assays indicated that these polymers were toxic at high concentrations when not complexed to DNA or at certain polymer:DNA ratios. Poly(ethyleneimine) co-polymers with side-chain grafted PNIPAm were shown to be less toxic than poly(ethyleneimine) alone or PNIPAm-co-(N,N'-dimethylaminoethylmethacrylate) linear co-polymers and the effects were concentration dependent. Confocal micrographs of labeled polymers and DNA indicated rapid cellular entry for all the complexes but expression of Green Fluorescent Protein was achieved only when the branched PEI-PNIPAm co-polymers were used as vectors. The results indicate that design of appropriate co-polymer components and overall polymer architecture can be used to mediate, and perhaps ultimately control, DNA transport and transgene expression.

Acrylic Resins↗
PubMed2006

Improvement of cell viability and hirudin production by ascorbic acid in Pichia pastoris fermentation.

In recombinant Pichia pastoris fermentation for hirudin production, copious cells were not viable and most of the secreted hirudin molecules were C-terminally truncated at the end of fermentation. In this work, the influences of reactive oxygen species (ROS) on cell viability and hirudin production were subsequently studied. In contrast to the untreated control condition, the addition of ascorbic acid at the methanol fed-batch phase could obviously relieve the damage of intracellular ROS to cell membranes. As a result, the cell viability could be increased to 91% from 74% in control at the end of fermentation and the extracellular proteolysis of hirudin reduced. Intact and total hirudin production, by supplying ascorbic acid, could reach 2.90 and 5.03 g/l, respectively, in contrast to 1.75 and 4.70 g/l at the control condition. Ascorbic acid, 4 mmol/l or more, in the fermentation broth increased markedly the production of the intact hirudin, despite a little effect on total hirudin production.

Ascorbic Acid↗
PubMed2001

Potential problems with fluorescein diacetate assays of cell viability when testing natural products for antimicrobial activity.

There are two potential problems in the use of fluorescein diacetate (FDA) as a measure of cell viability. The first is the hydrolysis of FDA to fluorescein in the absence of live cells and the second is the quenching of fluorescence by assay solutions. We show that common media components such as tryptone, peptone and yeast extract all promote hydrolysis of FDA in the absence of live cells, as do Tris-HCl and sodium phosphate buffers. As a consequence, various microbiological media promote hydrolysis of FDA in the absence of live cells. Different media were also shown to reduce the amount of visible fluorescence of fluorescein. Diluting the medium decreases the background hydrolysis of FDA as well as increases the amount of visible fluorescence. Both problems should be considered when using FDA as an indicator of cell viability when testing natural products for antimicrobial activity.

Anti-Infective Agents↗
PubMed1993

Bacterial biofilm formation on the bladder epithelium of spinal cord injured patients. II. Toxic outcome on cell viability.

As a follow up to our first study of 10 spinal cord injured patients, a further 8 patients were investigated over 2 months for biofilm formation on their bladder epithelial cells and for evidence that these uropathogens damage the host bladder. All the patients were found to be colonized with uropathogens, regardless of whether or not they were receiving antibiotics. Using vital staining, it was discovered that there was a significant reduction (33%) in bladder cell viability in the presence of bacterial biofilms compared to controls. This was not associated with cell turnover rates. In vitro tests showed a similar reduction in cell viability when uropathogens were incubated with bladder cells. In addition, white cell counts were significantly elevated in the patients' urine, indicative of an infectious and/or inflamed state. There was no difference between symptomatic and asymptomatic patients in their mean bacterial adhesion counts. Patients were just as likely to be symptomatic as asymptomatic when on antibiotics. In summary, the presence of virulent organisms in the bladder does adversely affect the host, even when the patient has insignificant signs and symptoms of infection, thereby raising concerns over the decision not to treat the patient. Unless specific antibiotics are used which eradicate adherent biofilms from the bladder, the treatment of symptomatic patients will only impact upon the signs and symptoms in some patients, and not alter their susceptibility to reinfection.

Adult↗
PubMed1998

Effect of alternative peritoneal dialysis solutions on cell viability, apoptosis/necrosis and cytokine expression in human monocytes.

BACKGROUND: Cellular function, cell viability and the cytokine network of human monocytes are influenced by the specific composition of peritoneal dialysis (PD) fluids. In an in vitro study using isolated human blood monocytes, we investigated the effect of peritoneal dialysates containing amino acids (Amino) or glucose polymer (Glu-poly) instead of glucose (Glu) as the osmotic agent, and bicarbonate (Bic) or PBS instead of lactate (Lac) as a buffer. METHODS: The following parameters were studied: mitochondrial dehydrogenase activity (using the MTT assay), interleukin (IL)-6 and IL-8 release (ELISA) and cellular IL-6 mRNA expression after lipopolysaccharide (LPS) stimulation (using RT-PCR). FACS flow cytometry with annexin V and propidium iodide as markers and fluorescence microscopic methods were used to study the effects of the test fluids on cell necrosis and apoptosis. RESULTS: Glu/Lac pH 5.5 and Glu-poly/PBS pH 7.4 both significantly reduced mitochondrial dehydrogenase activity by more than 50% after 60 minutes of incubation (30.5 +/- 7.6%, 42.5 +/- 6.5%, referred to RPMI 1640 as 100%). Amino/Bic and Glu/Bic were both superior (Mtt assay > 63%). The rate of necrotic cells after 15 minutes of incubation measured by FACS was mostly increased with Glu/Lac pH 5.5 (29.9 +/- 4.0%). The rate of apoptotic cells, however, was not significantly different between the test solutions. The concentration of IL-6 in the supernatant of stimulated monocytes was highest with Glu/Bic (1023 +/- 278 pg/ml) and Amino/Bic (776 +/- 296 pg/ml) an lowest with Glu/lac pH 5.5 (46 +/- 22 pg/ml) and Glu-poly/PBS (32 +/- 13 pg/ml). IL-8 release from stimulated monocytes showed a similar pattern. Glu-poly/PBS showed a suppressive effect on IL-6 mRNA expression (ratio IL-6/beta-Actin, 0.4 +/- 0.25 vs. RPMI 1.5 +/- 3.6). CONCLUSIONS: Bicarbonate buffered solutions both with glucose or amino acids as osmotic agents were superior when regarding cell metabolism, viability and cytokine release, while lactate buffered solutions and Glu-poly/PBS showed some reduced biocompatibility pattern for monocytes in vitro.

Actins↗
PubMed1997

Comparison of various transport media on human periodontal ligament cell viability.

The purpose of this study was to determine the ability of various solutions to maintain human periodontal ligament cell (PDL) viability in vitro. PDL cells were obtained from extracted third molars and premolars of healthy individuals. These cells were placed into 24-well culture plates containing milk, Save-A-Tooth, Save-A-Tooth supplemented with platelet-derived growth factor-BB (PDGF), or Gatorade at a concentration of approximately 80,000/well. Cells left dry served as negative controls, and cells placed in Eagles' Minimal Essential Medium served as positive controls. At 1, 2, 4, 8, and 12 h, cell viability was evaluated using an MTS assay and an ELISA plate reader to determine optical density. ANOVA and Student-Newman-Keuls tests indicated that milk and Save-A-Tooth with PDGF are suitable as transport medium for avulsed teeth and that the addition of PDGF to Save-A-Tooth may enhance its ability to maintain PDL cell viability. They also suggests that Gatorade would be unsuitable as a transport medium.

Animals↗
PubMed1999

Lack of squamous cell lung carcinoma in vitro chemosensitivity to various drug regimens in the adenosine triphosphate cell viability chemosensitivity assay.

A pilot study on squamous cell lung carcinoma (LC) chemosensitivity in adenosine triphosphate cell viability chemosensitivity assay (ATP-CVA) was performed. Besides the histological investigation, a modified ATP-CVA was used for the analysis of cancer cell chemosensitivity to four drug regimens, including topotecan, a promising agent for non-small-cell lung cancer (NSCLC) chemotherapy. Results of in vitro chemosensitivity testing showed chemoresistance or only weak response in the predominant amount of tumors.

Aged↗
PubMed1996

Structural changes and cell viability of cultured epithelium after freezing storage.

Numerous clinical reports have shown the utility of cultured epithelial grafting in the field of plastic and reconstruction surgery. Recently, freezing storage of the cultured epithelium has been tried and has successfully grafted after thawing. It is clinically convenient if it is possible for cultured epithelium to keep its normal structure and viability. However, few papers have described the structural changes in cultured epithelium after freezing storage. In the present study, the morphological changes and cell viability of cultured mucosal epithelial sheets after freezing were studied in comparison with cultured epidermal sheets. Furthermore, we discuss the effect of storage temperature and cryoprotectants. As a result, there were some structural changes such as vacuolar degeneration in the cultured mucosal sheets using dimethyl sulphoxide (DMSO) as a cryoprotectant. Such changes were more clearly observed at -80 degrees C than at -196 degrees C with DMSO. However, little morphological change was observed in both epithelial sheets cultured with glycerin. The cell viability analysed by flow cytometry showed that more than 62% of the cells kept their viability after freezing storage. These results suggest that the optimum conditions of freezing for cultured epithelium were -196 degrees C storage by slow cooling methods with glycerin as a cryoprotectant.

Cell Survival↗
PubMed1987

The ATP assay is more sensitive than the succinate dehydrogenase inhibition test for predicting cell viability.

The succinate dehydrogenase inhibition (SDI) test and the adenosine triphosphate (ATP) assay, are both used for in vitro human tumor chemosensitivity testing. We exposed HeLa cells to various concentrations of mitomycin C for 1, 2 or 3 days and found that the decrease in number of viable cells correlated with that of succinate dehydrogenase (EC 1.3.99.1) activity and that of intracellular ATP level of the viable cells. In the dead cells, the ATP level was extensively decreased, but the succinate dehydrogenase activity remained at a level of 24% of that of mitomycin C-untreated viable cells, even on day 3. Thus, the ATP level better reflected the cell viability. In clinical situations, the succinate dehydrogenase activity and the ATP level are assayed in whole cells following exposure to anticancer drugs, therefore the activity remaining in the dead cells must be taken into consideration for the chemosensitive prediction with the SDI test, but not with the ATP assay. This higher sensitivity of the ATP assay will enable a more accurate prediction of cell viability.

Adenosine Triphosphate↗
PubMed1999

Progesterone maintains large rat granulosa cell viability indirectly by stimulating small granulosa cells to synthesize basic fibroblast growth factor.

Ovarian follicles are composed of small and large granulosa cells (GCs). Since progesterone (P4) inhibits large GCs from undergoing apoptosis, studies were designed to determine whether both sizes of GCs bind P4. These studies revealed that fluorescein isothiocyanate-BSA-P4 bound only to the surface membranes of small GCs. This binding was steroid-specific and inhibited by an antibody directed against the ligand-binding domain of the nuclear P4 receptor (PR). In addition, a cell-impermeable derivative of P4, BSA-conjugated P4, was as effective as P4 in preventing apoptosis. Quantitative in situ hybridization studies showed that P4 increased the relative amount of basic fibroblast growth factor (bFGF) mRNA expressed per cell as well as the percentage of small GCs that expressed bFGF. To determine whether the anti-apoptotic action of P4 was mediated by bFGF, GCs were cultured in control medium supplemented with either P4, a neutralizing antibody to bFGF, or both P4 and the bFGF antibody. The results from this study demonstrated that P4 suppressed apoptosis and that this effect was attenuated in presence of the bFGF antibody. Basic FGF also prevented GC apoptosis, and its action was not influenced by either the PR antagonist (RU-486), an inhibitor of P4 synthesis (aminoglutethimide), or a PR antibody. Finally, FGF receptors were detected on both small and large GCs. Collectively, these data support the hypothesis that P4 acts through a putative membrane receptor on small GCs to stimulate the synthesis of bFGF. Basic FGF then activates its receptors within large GCs, and this initiates a signal transduction pathway that maintains large GC viability.

Aminoglutethimide↗
PubMed2006

Leptin enhances STAT-3 phosphorylation in HC11 cell line: effect on cell differentiation and cell viability.

Leptin is produced in the mammary gland by the fat tissue or by the mammary epithelium. The aim of this study was to investigate the role of leptin on mammary epithelial cell differentiation and cell viability. This study was conducted using the mouse mammary epithelial cell line HC11. We show that leptin, synergizes with prolactin to increase beta-casein gene expression during mammary epithelial cell differentiation. This was correlated with increased phosphorylation of the signal transducer and activator of transcription 3 (STAT-3). Inactivating the function of STAT-3 by expression of a short hairpin RNA demonstrated that the effect of leptin on beta-casein expression is mediated by STAT-3. Secondly, cells in which STAT-3 had been inactivated showed increased cell viability compared to controls and were resistant to the negative effect mediated by leptin. Further, leptin triggers apoptosis in mammary epithelial cells cultivated in non-differentiating conditions. Taken together, these results suggest that leptin, by activating STAT-3, may act as a paracrine factor modulating mammary epithelial cell function.

Animals↗
PubMed1999

Effect of garlic active principle, diallyl disulfide, on cell viability, lipid peroxidation, glutathione concentration and its related enzyme activities in primary rat hepatocytes.

This study investigated the effects of various concentrations and incubation time intervals of diallyl disulfide (DADS), the active principle of garlic, on: 1. cell viability, 2. lipid peroxidation, and 3. glutathione (GSH) concentration and its related enzyme activities of rat hepatocytes. According to the results of LDH leakage and microscopic examination, 0.5 and 1 mM DADS did not significantly affect the viability of hepatocytes. However, significant decrease in cell viability according to increased LDH leakage and significant changes in morphology of hepatocytes were observed at 2 mM DADS (P < 0.05). Lipid peroxidation was also detected when the hepatocytes were treated with 2 mM DADS. At 0.5 mM DADS, a higher GSH content was found in the hepatocytes although not at a statistically significant level. 0.5 and 1 mM DADS has little effect on the activities of glutathione-S-transferase (GST) and glutathione peroxidase (GPx); however a significant decrease in GST, GPx and glutathione reductase (GRd) activities was observed at 2 mM DADS. Once the media of 2 mM DADS was replaced with fresh medium at 24 hr treatment, the activities of GST, GRd and GPx were recovered, although they were still lower than the control values.

Allyl Compounds↗
PubMed1996

Effect of the active principle of garlic--diallyl sulfide--on cell viability, detoxification capability and the antioxidation system of primary rat hepatocytes.

The objectives of this study were to investigate the effects of various concentrations and incubation time intervals of diallyl sulfide (DAS), an active principle of garlic, on cell viability, and glutathione (GSH) concentration and its related enzymes activities in rat hepatocytes. According to the results of lactate dehydrogenase (LDH) leakage and microscopic examination, 0.5 or 1 mM DAS treatment did not have any adverse effects on the viability of hepatocytes. Intracellular GSH contents of cells treated with 0.5 and 1 mM DAS (58.6 and 66.4 nmol GSH/mg protein, respectively) were higher than in the controls (54.2 nmol GSH/mg protein), around 8-23%, at 24 hr of incubation; a significant difference (P < 0.05) was observed for 1 mM DAS treatment at 48 hr. This phenomenon is beneficial to the detoxification and antioxidation capabilities of hepatocytes. Further, when the hepatocytes were treated with 0.5 or 1 mM DAS, the activities of glutathione S-transferase (GST), glutathione peroxidase (GPx) and glutathione reductase (GRd) were almost the same as those of the controls. On the other hand, treatment with 5 mM DAS was associated with a significant decrease (P < 0.05) in cell viability, namely in increased LDH leakage (50% at 24-hr treatment), significant changes in the morphology of the hepatocytes, low intracellular GSH level (45% lower than in the controls at 24-hr treatment), and low activities of GST, GPx and Grd.

Allyl Compounds↗
PubMedDate not supplied

Conformational changes in gastric carcinoma cell membrane protein correlated to cell viability after treatment with adamantyl maleimide.

BACKGROUND: In order to investigate the mechanism of the effects of the anticancer drug adamantyl maleimide (AMI) on the in vitro growth of a human gastric carcinoma cell line (SC-M1), the membrane protein conformation on the cell surface after treatment with AMI was studied. MATERIALS AND METHODS: The interaction of AMI with SC-M1 cell line was studied by reflectance Fourier transform infrared (FT-IR) microspectroscopy. The cell viability was also determined by the trypan blue exclusion method. RESULTS: FT-IR microscopic study provided evidence that the conformational conversion of the membrane proteins of the SC-M1 cell line from alpha-helix to beta-sheet was found evident, but was dependent on the AMI concentrations used and the time of treatment. AMI not only interacted with the membrane protein on the cell surface, but also entered into cells to interact with the nucleic acids. CONCLUSIONS: The relationship between membrane protein conformational changes and the cell viability of SC-M1 cell line was evident. The AMI-induced apoptosis in SC-M1 cell line was also supposed.

Adamantane↗
PubMed2000

Penetration of Escherichia coli O157:H7 into lettuce tissues as affected by inoculum size and temperature and the effect of chlorine treatment on cell viability.

Penetration of Escherichia coli O157:H7 into iceberg lettuce tissues and the effect of chlorine treatment on cell viability were evaluated. Attachment of different inoculum levels (10(9), 10(8), and 10(7) CFU/ml) was examined by determining the number of cells at the surface and the cut edge of lettuce leaves (2 by 2 cm). E. coli O157:H7 attached preferentially to cut edges at all inoculum levels, with greater attachment per cm2 of lettuce at higher inoculum levels. A longer attachment time allowed more cells to attach at both sites. Immunostaining with a fluorescein isothiocyanate-labeled antibody revealed that cells penetrated into lettuce leaves from cut edges. Cells showed greater penetration when lettuce was held at 4 degrees C compared with 7, 25, or 37 degrees C and were detected at an average of 73.5 +/- 16.0 microm below the surfaces of cut tissues. Penetrating cells were mostly found at the junction of lettuce cells. The viability of attached cells after treatment with 200 mg/liter (200 ppm) of free chlorine for 5 min was examined by plating on tryptic soy agar and by a nalidixic acid elongation method. Although chlorine treatment caused significant reduction in attachment (0.7- and 1.0-log reduction at surfaces and cut edges, respectively), cells remained attached at high numbers (7.9 and 8.1 log CFU/cm2 at surfaces and cut edges, respectively). Elongated cells were observed in stomata and within the tissues of the lettuce, indicating they were protected from contact with chlorine.

Bacterial Adhesion↗
PubMedDate not supplied

Flow cytometric evaluation of apoptosis and cell viability as a criterion of anti-tumour drug toxicity.

BACKGROUND: Determination of the drug concentration required to kill 50% of the tumour cells (EC50) does not take into account the propensity of cells to undergo apoptosis and necrosis. These 2 parameters and the viable cells are here assessed by a flow cytometric (FC) approach using propidium iodide (PI) and FITC-Annexin V staining. MATERIALS AND METHODS: A number of carcinoma cell lines of defined p53 status were exposed to cis-PtII for 24 hours, stained with PI and FITC-Annexin V and analyzed by FC. Unstained viable cells, early apoptotic cells and necrotic cells were scored separately in dual parameter plots of green fluorescence (FITC) against red fluorescence (PI) to generate dose response curves. RESULTS: EC50 values for cell viability were found to be 1-4 times higher than survival data from colony assays resembling data obtained by MTT or Crystal Violet vital dye staining. Percentage apoptosis measured by Annexin V binding was in agreement with microscopic scoring of apoptotic cells after Acridine Orange staining. CONCLUSION: The FC assay described gives a good estimate of cell viability resembling data from vital dye staining assays and provides additional information on apoptosis and necrosis. FC data from Annexin V binding and microscopic scoring after Acridine Orange staining were in excellent agreement.

Antineoplastic Agents↗