Effect of CTAB and procain hydrochloride on neutral red microstructure in CTAB micelle

A sol-gel based fiber-optic biosensor with acetylcholinesterase as the biorecognition element has been developed for the rapid determination of organophosphorus pesticides. Nine fluorescent indicators, acridine, acridine orange, neutral red, DAPI, rhodamine B, fluorescein, umbelliferone, FITC on celite and FITC-dextran, have been examined to optimize the fiber-optic system. Results showed that acridine and FITCs were sensitive to the change of pH value caused by the enzyme-substrate catalysis reaction. However, the sensitivity of acridine was 260 times lower than that of FITCs. Higher toxicity of acridine to acetylcholinesterase than FITC was also observed. Moreover, the high-molecular-weight FITC-dextran showed low leakage rate when immobilizing using sol-gel technology, showing that the FITC-dextran was a suitable pH sensitive fluorescent indicator for the OPPs biosensor. The response of the fiber-optic biosensor to the substrate, acetylcholine, was highly reproducible (RSD=3.5%). A good linearity of acetylcholine in the range from 0.5 to 20 mM was also obtained (R2=0.98). Furthermore, a 30% inhibition can be achieved in 30min when 152 ppb paraoxon was added into the system. The results show the possibility for real-time determination of organophosphorus pesticides by using the biosensor developed in this study.

Download Full-text

Examining bivalve fecundity: oocyte viability revealed by Neutral Red vital staining

Aquaculture International ◽

10.1007/s10499-021-00686-6 ◽

2021 ◽

Author(s):

Peter G. Beninger ◽

Daphné Chérel ◽

Lucie Kessler

Keyword(s):

Vital Staining ◽

Neutral Red

Download Full-text

GASTRIC EXCRETION OF NEUTRAL RED

JAMA ◽

10.1001/jama.1925.02670110008003 ◽

1925 ◽

Vol 85 (11) ◽

pp. 794 ◽

Cited By ~ 5

Author(s):

PERCY B. DAVIDSON

Keyword(s):

Neutral Red

Download Full-text

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

Alternatives to Laboratory Animals ◽

10.1177/026119299802600511 ◽

1998 ◽

Vol 26 (5) ◽

pp. 679-708 ◽

Cited By ~ 5

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.

Download Full-text

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

Alternatives to Laboratory Animals ◽

10.1177/026119299202000119 ◽

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.

Download Full-text