In‐Vivo Estimation of Tissue Electrical Conductivities of a Rabbit Eye for Precise Simulation of Electric Field Distributions during Ocular Iontophoresis

2021 ◽  
Author(s):  
Sangjun Lee ◽  
Chany Lee ◽  
Euijin Kim ◽  
Song Ah. Ko ◽  
Se‐Na Kim ◽  
...  
Keyword(s):  
Electric Field ◽  
Rabbit Eye ◽  
Field Distributions ◽  
Electrical Conductivities ◽  
Precise Simulation

Application of the EYTEX™ System to the Evaluation of Cosmetic Products and their Ingredients

1992 ◽  
Vol 20 (1) ◽  
pp. 146-163
Author(s):  
Francis H. Kruszewski ◽  
Laura H. Hearn ◽  
Kyle T. Smith ◽  
Janice J. Teal ◽  
Virginia C. Gordon ◽  
...  
Keyword(s):  
Double Blind ◽  
Eye Irritation ◽  
Ocular Irritation ◽  
Rabbit Eye ◽  
Wide Range ◽  
High Concentrations ◽  
Alkaline Membrane ◽  
Positive Agreement

465 cosmetic product formulations and raw ingredients were evaluated with the EYTEX™ system to determine the potential of this in vitro alternative for identifying eye irritation potential. The EYTEX™ system is a non-animal, biochemical procedure developed by Ropak Laboratories, Irvine, CA, that was designed to approximate the Draize rabbit eye irritation assay for the evaluation of ocular irritation. Avon Products Inc. provided all the test samples, which included over 30 different product types and represented a wide range of eye irritancy. All the EYTEX™ protocols available at the time of this study were used. Samples were evaluated double-blind with both the membrane partition assay (MPA) and the rapid membrane assay (RMA). When appropriate, the standard assay (STD) and the alkaline membrane assay (AMA) were used, as well as specific, documented protocol modifications. EYTEX™ results were correlated with rabbit eye irritation data which was obtained from the historical records of Avon Products Inc. A positive agreement of EYTEX™ results with the in vivo assay was demonstrated by an overall concordance of 80%. The assay error was 20%, of which 18% was due to an overestimation of sample irritancy (false positives) and 2% was attributed to underestimation (false negatives). Overestimation error in this study was due in part to the inability of the protocols to accurately classify test samples with very low irritation potential. Underestimation of sample irritancy was generally associated with ethoxylated materials and high concentrations of specific types of surfactants. 100% sensitivity and 85% predictability were described by the data, indicating the efficiency of EYTEX™ in identifying known irritants. A specificity rate of 39% showed the EYTEX™ assay to be weak in discerning non-irritants. However, the EYTEX™ protocols used in this study were not designed to identify non-irritants. A compatibility rate of 99% proved the effectiveness of the EYTEX™ assay in accommodating a diversity of product types. The EYTEX™ system protocols, when used appropriately, can provide a conservative means of assessing the irritant potential of most cosmetic formulations and their ingredients.

Factors Controlling Electropermeabilisation of Cell Membranes

2002 ◽  
Vol 1 (5) ◽  
pp. 319-327 ◽  
Author(s):  
M. P. Rols ◽  
M. Golzio ◽  
B. Gabriel ◽  
J. Teissié
Keyword(s):  
Cell Surface ◽  
Electric Field ◽  
Pulse Duration ◽  
Cell Membranes ◽  
Physical Parameters ◽  
Local Exchange ◽  
Physical Mechanisms ◽  
A Cell

Electric field pulses are a new approach for drug and gene delivery for cancer therapy. They induce a localized structural alteration of cell membranes. The associated physical mechanisms are well explained and can be safely controlled. A position dependent modulation of the membrane potential difference is induced when an electric field is applied to a cell. Electric field pulses with an overcritical intensity evoke a local membrane alteration. A free exchange of hydrophilic low molecular weight molecules takes place across the membrane. A leakage of cytosolic metabolites and a loading of polar drugs into the cytoplasm are obtained. The fraction of the cell surface which is competent for exchange is a function of the field intensity. The level of local exchange is strongly controlled by the pulse duration and the number of successive pulses. The permeabilised state is long lived. Its lifetime is under the control of the cumulated pulse duration. Cell viability can be preserved. Gene transfer is obtained but its mechanism is not a free diffusion. Plasmids are electrophoretically accumulated against the permeabilised cell surface and form aggregates due to the field effect. After the pulses, several steps follow: translocation to the cytoplasm, traffic to the nucleus and expression. Molecular structural and metabolic changes in cells remain mostly poorly understood. Nevertheless, while most studies were established on cells in culture ( in vitro), recent experiments show that similar effects are obtained on tissue ( in vivo). Transfer remains controlled by the physical parameters of the electrical treatment.

Pilocarpine hydrochloride liposomes: characterization in vitro and preliminary evaluation in vivo in rabbit eye

1984 ◽  
Vol 1 (3) ◽  
pp. 203-216 ◽  
Author(s):  
S. Benita ◽  
J. D. Plenecassagne ◽  
G. Cavé ◽  
D. Drouin ◽  
P. Le Hao Dong ◽  
...  
Keyword(s):  
Preliminary Evaluation ◽  
Rabbit Eye

Nerve branching is induced and oriented by a small applied electric field

1990 ◽  
Vol 95 (4) ◽  
pp. 605-615
Author(s):  
C.D. McCaig
Keyword(s):  
Electric Field ◽  
Dimethyl Sulfoxide ◽  
Nerve Regeneration ◽  
Applied Electric Field ◽  
Large Majority ◽  
Ganglioside Gm1 ◽  
Pharmacological Agents ◽  
Extrinsic Cues

Nerve branching is controlled by intrinsic and extrinsic cues, one of which may be a small applied electric field. Lateral processes were induced by passing current through a micropipette placed at 90 degrees to the shaft of a developing nerve. The appearance of processes was a polarised event with a large majority arising from the cathodal facing side of nerves. Whilst an electric field alone may promote branching, the presence of dimethyl sulfoxide (DMSO) or the ganglioside GM1 enhanced branching of developing nerves. It is likely that an applied electric field promotes microtubule disassembly locally along the neurite shaft and that this can lead to a polarised rearrangement of the neuronal cyto-skeleton. It is suggested that the use of an applied electric field in conjunction with these pharmacological agents might enhance nerve regeneration in vivo.

Electric Field Distributions in an Ionized Gas. II

1960 ◽  
Vol 118 (3) ◽  
pp. 626-631 ◽  
Author(s):  
Bernard Mozer ◽  
Michel Baranger
Keyword(s):  
Electric Field ◽  
Ionized Gas ◽  
Field Distributions
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