A novel method for tyrosine assessment in vitro by using fluorescence enhancement of the ion-pair tyrosine-neutral red dye photo probe

2012 ◽  
Vol 4 (8) ◽  
pp. 2323 ◽  
Author(s):  
M. S. Attia ◽  
A. O. Youssef ◽  
Amr A. Essawy
Keyword(s):  
Fluorescence Enhancement ◽  
Neutral Red ◽  
Ion Pair ◽  
Novel Method ◽  
Photo Probe ◽  
Red Dye

scholarly journals L929 cell response to root perforation repair cements: an in vitro cytotoxicity assay

2009 ◽  
Vol 20 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Rosana Belchior Miranda ◽  
Sandra Rivera Fidel ◽  
Maria Aparecida Affonso Boller
Keyword(s):  
Morphological Changes ◽  
Mineral Trioxide Aggregate ◽  
L929 Cell ◽  
Neutral Red ◽  
In Vitro Cytotoxicity ◽  
Mean Values ◽  
Nonviable Cell ◽  
Red Dye ◽  
Positive Controls

This study compared the cytotoxicity of an experimental epoxy-resin and calcium hydroxide-based cement (MBPc), gray mineral trioxide aggregate (MTA) and white mineral trioxide aggregate (WMTA) using the agar overlay method with neutral red dye. L929 cells were seeded into 6-well culture plates where 48-h set test materials were placed on the agar overlay, in triplicate. Teflon and natural rubber served as negative and positive controls. After an incubation period of 24 h at 37ºC in a humidified atmosphere of 5% CO2 in air, a discolored area around the samples and the positive controls could be observed and measured per quadrant. The mean values were compared and converted into grades to classify the results according to the table of cytotoxicity grades according to the Standard Operating Procedures (SOP) of the Oswaldo Cruz Foundation, Brazil. The nonviable cell areas and the morphological changes in the cells were observed with an inverted microscope. The results showed grade 1 (slight) for the two types of MTA (p>0.05) and grade 2 (mild) for the MBPc (p<0.001). All samples met the requirements of the test as none of the cultures showed reactivity higher than grade 2.

scholarly journals In vitro cytotoxicity of self-curing acrylic resins of different colors

2014 ◽  
Vol 19 (4) ◽  
pp. 66-70 ◽  
Author(s):  
Luciana Borges Retamoso ◽  
Taís de Morais Alves da Cunha ◽  
Matheus Melo Pithon ◽  
Rogério Lacerda dos Santos ◽  
Fernanda Otaviano Martins ◽  
...  
Keyword(s):  
Acrylic Resin ◽  
Neutral Red ◽  
In Vitro Cytotoxicity ◽  
Group 4 ◽  
Acrylic Resins ◽  
L929 Fibroblast ◽  
Glass Specimen ◽  
Group 2 ◽  
Red Dye

OBJECTIVE: The aim of this study was to assess the in vitro cytotoxicity of acrylic resins of different colors over time. METHODS: Specimens were divided into 4 groups (n = 6) according to the color of the acrylic resin (Orto Class, Clássico, Campinas, São Paulo, Brazil): Group 1: clear acrylic resin; group 2: pink acrylic resin; group 3: blue acrylic resin and group 4: green acrylic resin. All specimens were fabricated according to the mass manipulation technique and submitted to mechanical polishing protocol. The control was performed with an amalgam specimen (C+), a glass specimen (C-) and cell control (CC). Specimens were immersed in Minimum Eagle's Medium (MEM) and incubated for 24 h at 37o C. The extracts from the experimental material were filtered and mixed with L929 fibroblast. Cytotoxicity was evaluated at 4 different times, 24, 48, 72 and 168 h. After contact, cells were incubated for 24 h and added to 100 µ of 0.01% neutral red dye. The cells were incubated for 3 h for pigment incorporation and fixed. Cells viability was determined by a spectroscopic (BioTek, Winooski, Vermont, USA) with a 492-nm wavelength λ=492 nm). RESULTS: There were no statistical differences between the experimental groups and the CC and C- groups. CONCLUSION: Clear, pink, blue and green self-curing acrylic resins fabricated by means of the mass manipulation technique and mechanically polished are not cytotoxic. Neither the pigment added to the self-curing acrylic resin nor the factor of time influenced the cytotoxicity of the material.

Detecting the Implant in vitro Microleakage Using Spectrophotometry and Neutral Red Dye

2017 ◽  
Vol 68 (9) ◽  
pp. 2151-2154
Author(s):  
Tareq Hajaj ◽  
Serban Talpos ◽  
Emilia Ianes ◽  
Adrian Candea ◽  
Adrian Neagu ◽  
...  
Keyword(s):  
Success Rate ◽  
Neutral Red ◽  
Oral Bacteria ◽  
Local Inflammation ◽  
Dynamic Conditions ◽  
Implant Abutment ◽  
Implant Therapy ◽  
Almost All ◽  
Red Dye

Implants are one of the most innovative and less invasive prosthetic procedures available. Almost all types of edentations can, nowadays, be treated with an implant-retained prosthetic piece, either fixed or removable. But regardless of the development in the industry over the last decades and the high success rate - estimated at over 95% - there are still some problems concerning single or multi-unit restorations[1-3]. One of the main concerns about implant therapy today is the microleakage phenomenon. The microleakage appears between the implant and the abutment and, due to masticatory forces, it creates a pump effect which can carry the oral bacteria inside the implant, where it�s almost impossible to reach, thus, creating a local inflammation, called peri-implantitis[4-6] . Many authors have tried to identify and quantify the phenomenon by diverse means, but a consensus hasn�t been reached on how or when exactly it appears. In the present study, Neutral Red dye was used to determine the sealing of the implant-abutment interface in dynamic conditions, with the help of the spectrophotometry.

Penetration gland secretion by hexacanths of Hymenolepis diminuta

Parasitology ◽  
1974 ◽  
Vol 68 (3) ◽  
pp. 303-311 ◽  
Author(s):  
R. C. Lethbridge ◽  
M. F. Gijsbers
Keyword(s):  
Surface Membrane ◽  
Neutral Red ◽  
Hymenolepis Diminuta ◽  
Penetration Gland ◽  
Tissue Extracts ◽  
Time Period ◽  
Red Dye ◽  
Gland Material

The rate of expulsion of penetration gland material was determined from photomicrographs of Hymenolepis diminuta hexacanths stained with neutral red dye at intervals after hatching in vitro. Identical secretory rates were recorded for hexacanths incubated in either Tyrode's solution or Tyrode's solution plus an extract of the midgut of Tenebrio molitor. In both media the reduction in stained material observed in the glands after 135 min incubations was equivalent to that observed for hexacanths that had had opportunity to penetrate in vivo during the same time period. These results were interpreted as indicating that the in vivo secretory pattern was similar to that observed in vitro, and that chemical stimuli from the tissue extracts were not required to initiate secretion. Microdensitometric readings also demonstrated a quantitative decrease in dye within the glands as incubation time increased. Ultrastructural examination of the glands showed that their secretory inclusions were exported via ducts to the epithelial cytoplasm where they accumulated in discrete blebs enclosed by the surface membrane. These inclusion-filled, membrane-bounded blebs were apparently formed and released continuously until, after approximately 2 h, only a few inclusions remained in the penetration glands.

A novel assay for the detection of anthelmintic activity mediated by cuticular damage to nematodes: validation onCaenorhabditis elegansexposed to cysteine proteinases

Parasitology ◽  
2017 ◽  
Vol 144 (5) ◽  
pp. 583-593 ◽  
Author(s):  
A. M. PHIRI ◽  
D. I. DE POMERAI ◽  
D. J. BUTTLE ◽  
J. M. BEHNKE
Keyword(s):  
Colorimetric Assay ◽  
Anthelmintic Activity ◽  
Neutral Red ◽  
Cysteine Proteinases ◽  
C Elegans ◽  
Viable Cells ◽  
Knockout Mutants ◽  
Red Dye ◽  
Hydrolysis Of

SUMMARYPlant cysteine proteinases (CPs) fromCarica papayakill parasitic and free-living nematodesin vitroby hydrolysis of the worm cuticle, a mechanism that is different to all commercially available synthetic anthelmintics. We have developed a cheap and effective, rapid-throughputCaenorhabditis elegans-based assay for screening plant CP extracts for anthelmintic activity targeting cuticular integrity. The assay exploits colorimetric methodology for assessment of cuticular damage, and is based on the ability of viable cells to incorporate and bind Neutral red dye within lysosomes and to release the dye when damaged. Living worms are pre-stained with the dye, exposed to CPs and then leakage of the dye through the damaged cuticle is quantified by spectrophotometry. In contrast to motility assays and semi-subjective interpretation of microscopical images, this colorimetric assay is independent of observer bias. Our assay was applied to a series ofC. elegans busmutant strains with leaky cuticles and to cystatin knockout mutants. At ambient temperature and over 0.5–24 h, bothbusmutants and the cystatin knockouts were highly susceptible to CPs, whereas wild-type Bristol N2 worms were essentially unstained by Neutral red and unaffected by CPs, providing validation for the utility of this assay.

scholarly journals Efficient and selective catalytic hydroxylation of unsaturated plant oils: a novel method for producing anti-pathogens

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Ahmed M. Senan ◽  
Binru Yin ◽  
Yaoyao Zhang ◽  
Mustapha M. Nasiru ◽  
Yong‐Mei Lyu ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
In Vitro Study ◽  
Functional Method ◽  
Plant Oils ◽  
Main Process ◽  
Catalytic Method ◽  
Novel Method ◽  
Pharmaceutical Industries ◽  
Increasing Demand

AbstractWith the increasing demand for antimicrobial agents and the spread of antibiotic resistance in pathogens, the exploitation of plant oils to partly replace antibiotic emerges as an important source of fine chemicals, functional food utility and pharmaceutical industries. This work introduces a novel catalytic method of plant oils hydroxylation by Fe(III) citrate monohydrate (Fe3+-cit.)/Na2S2O8 catalyst. Methyl (9Z,12Z)-octadecadienoate (ML) was selected as an example of vegetable oils hydroxylation to its hydroxy-conjugated derivatives (CHML) in the presence of a new complex of Fe(II)-species. Methyl 9,12-di-hydroxyoctadecanoate 1, methyl-9-hydroxyoctadecanoate 2 and methyl (10E,12E)-octadecanoate 3 mixtures is produced under optimized condition with oxygen balloon. The specific hydroxylation activity was lower in the case of using Na2S2O8 alone as a catalyst. A chemical reaction has shown the main process converted of plantoils hydroxylation and (+ 16 Da) of OH- attached at the methyl linoleate (ML-OH). HPLC and MALDI-ToF-mass spectrometry were employed for determining the obtained products. It was found that adding oxidizing agents (Na2S2O8) to Fe3+ in the MeCN mixture with H2O would generate the new complex of Fe(II)-species, which improves the C-H activation. Hence, the present study demonstrated a new functional method for better usage of vegetable oils.Producing conjugated hydroxy-fatty acids/esters with better antipathogenic properties. CHML used in food industry, It has a potential pathway to food safety and packaging process with good advantages, fundamental to microbial resistance. Lastly, our findings showed that biological monitoring of CHML-minimum inhibitory concentration (MIC) inhibited growth of various gram-positive and gram-negative bacteria in vitro study. The produced CHML profiles were comparable to the corresponding to previousstudies and showed improved the inhibition efficiency over the respective kanamycin derivatives.

A Study on UV Filter Chemicals from Annex VII of European Union Directive 76/768/EEC, in the In Vitro 3T3 NRU Phototoxicity Test

1998 ◽  
Vol 26 (5) ◽  
pp. 679-708 ◽  
Author(s):  
Horst Spielmann ◽  
Michael Balls ◽  
Jack Dupuis ◽  
Wolfgang J. W. Pape ◽  
Odile de Silva ◽  
...  
Keyword(s):  
Neutral Red ◽  
Optimum Concentration ◽  
Alternative Methods ◽  
Uv Filter ◽  
Eu Directive ◽  
Optimum Concentration Range ◽  
The Impact ◽  
Positive Results

In 1996, the Scientific Committee on Cosmetology of DGXXIV of the European Commission asked the European Centre for the Validation of Alternative Methods to test eight UV filter chemicals from the 1995 edition of Annex VII of Directive 76/768/EEC in a blind trial in the in vitro 3T3 cell neutral red uptake phototoxicity (3T3 NRU PT) test, which had been scientifically validated between 1992 and 1996. Since all the UV filter chemicals on the positive list of EU Directive 76/768/EEC have been shown not to be phototoxic in vivo in humans under use conditions, only negative effects would be expected in the 3T3 NRU PT test. To balance the number of positive and negative chemicals, ten phototoxic and ten non-phototoxic chemicals were tested under blind conditions in four laboratories. Moreover, to assess the optimum concentration range for testing, information was provided on appropriate solvents and on the solubility of the coded chemicals. In this study, the phototoxic potential of test chemicals was evaluated in a prediction model in which either the Photoirritation Factor (PIF) or the Mean Photo Effect (MPE) were determined. The results obtained with both PIF and MPE were highly reproducible in the four laboratories, and the correlation between in vitro and in vivo data was almost perfect. All the phototoxic test chemicals provided a positive result at concentrations of 1μg/ml, while nine of the ten non-phototoxic chemicals gave clear negative results, even at the highest test concentrations. One of the UV filter chemicals gave positive results in three of the four laboratories only at concentrations greater than 100μg/ml; the other laboratory correctly identified all 20 of the test chemicals. An analysis of the impact that exposure concentrations had on the performance of the test revealed that the optimum concentration range in the 3T3 NRU PT test for determining the phototoxic potential of chemicals is between 0.1μg/ml and 10μg/ml, and that false positive results can be obtained at concentrations greater than 100μg/ml. Therefore, the positive results obtained with some of the UV filter chemicals only at concentrations greater than 100μg/ml do not indicate a phototoxic potential in vivo. When this information was taken into account during calculation of the overall predictivity of the 3T3 NRU PT test in the present study, an almost perfect correlation of in vitro versus in vivo results was obtained (between 95% and 100%), when either PIF or MPE were used to predict the phototoxic potential. The management team and participants therefore conclude that the 3T3 NRU PT test is a valid test for correctly assessing the phototoxic potential of UV filter chemicals, if the defined concentration limits are taken into account.

A New In Vitro Model for Predicting the Toxicity of Cosmetic Products

1992 ◽  
Vol 20 (1) ◽  
pp. 138-143
Author(s):  
Maria Carrara ◽  
Lorenzo Cima ◽  
Roberto Cerini ◽  
Maurizio Dalle Carbonare
Keyword(s):  
Cell Culture ◽  
Cultured Cells ◽  
Neutral Red ◽  
Total Protein Content ◽  
Cosmetic Products ◽  
Cell Culture Insert ◽  
A Cell ◽  
Vitro Model ◽  
Cosmetic Emulsions

A method has been developed whereby cosmetic products which are not soluble in water or in alcohol can be brought into contact with cell cultures by being placed in a cell culture insert, which is then placed in the cell culture well. Preliminary experiments were carried out with L929 cells, and cytotoxicity was evaluated by measuring neutral red uptake and the total protein content of treated cultured cells. Encouraging results were obtained in comparisons of three cosmetic emulsions and of one emulsion containing a range of concentrations of two preservatives, Kathon CG and Bronopol.

The EYTEX™ System and the Neutral Red Uptake Inhibition Assay in Cultured Hep G2 Cells as Alternative Methods for In Vivo Eye Irritation Following the EEC Protocol

1990 ◽  
Vol 17 (4) ◽  
pp. 325-333
Author(s):  
Paul J. Dierickx ◽  
Virginia C. Gordon
Keyword(s):  
Neutral Red ◽  
Alternative Methods ◽  
Inhibition Assay ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Eye Irritation ◽  
Uptake Inhibition ◽  
In Vitro Methods ◽  
Neutral Red Uptake

The neutral red uptake inhibition assay and the EYTEX™ system were investigated as alternative methods for the assessment of eye irritation, determined according to the EEC protocol. The 17 test chemicals used were mainly organic solvents. The xenobiotics were applied to Hep G2 cells for 24 hours at different concentrations. Neutral red uptake inhibition was then measured. The results are expressed as the NI50 value, which is the concentration of test compound required to induce a 50% reduction in neutral red uptake. The same chemicals were also tested as coded samples by the EYTEX™ test according to the manufacturer's directions. A nearly identical quantitative correlation was found for both in vitro methods with corneal opacity scores: r = 0.84 for EYTEX™ scores and r = 0.83 for log NI50, expressed in μg/ml. Whilst these correlations are certainly not perfect, it is clear that both in vitro methods can be used as valuable prescreening methods.

The Development and Evaluation of In Vitro Tests by the FRAME Alternatives Laboratory

1995 ◽  
Vol 23 (1) ◽  
pp. 75-90
Author(s):  
Richard H. Clothier ◽  
Karen A. Atkinson ◽  
Michael J. Garle ◽  
Rachel K. Ward ◽  
Angela Willshaw
Keyword(s):  
Research Programme ◽  
Neutral Red ◽  
In Vitro Cytotoxicity ◽  
In Vitro Tests ◽  
Dermal Toxicity ◽  
Mechanisms Of Toxicity ◽  
The Us ◽  
Detergent Association ◽  
Assay Methods

This review outlines the work which has been conducted in the FRAME Alternatives Laboratory during the first ten years of the FRAME Research Programme. A number of in vitro tests, including the kenacid blue, neutral red release and fluorescein leakage assay methods, have been evaluated and have subsequently been included in validation schemes organised by the US Soap and Detergent Association, the US Cosmetic, Toiletry and Fragrance Association, the European Commission and the European Cosmetic, Toiletry and Perfumery Association, as well as in the Scandinavian multicentre evaluation of in vitro cytotoxicity testing scheme. More recently, research has been undertaken in the areas of phototoxicity, immunotoxicity, dermal toxicity and intercellular communication, in addition to investigations into fundamental mechanisms of toxicity.

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