scholarly journals Design of Electroporation Process in Irregularly Shaped Multicellular Systems

Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 37 ◽  
Author(s):  
Luciano Mescia ◽  
Michele Alessandro Chiapperino ◽  
Pietro Bia ◽  
Claudio Maria Lamacchia ◽  
Johan Gielis ◽  
...  
Keyword(s):  
Pore Formation ◽  
External Medium ◽  
Dielectric Dispersion ◽  
Biological Cells ◽  
Nuclear Membranes ◽  
Cell Compartments ◽  
Cell Shapes ◽  
Irregular Cell ◽  
Smoluchowski’S Equation ◽  
Isolated Cell

Electroporation technique is widely used in biotechnology and medicine for the transport of various molecules through the membranes of biological cells. Different mathematical models of electroporation have been proposed in the literature to study pore formation in plasma and nuclear membranes. These studies are mainly based on models using a single isolated cell with a canonical shape. In this work, a space–time (x,y,t) multiphysics model based on quasi-static Maxwell’s equations and nonlinear Smoluchowski’s equation has been developed to investigate the electroporation phenomenon induced by pulsed electric field in multicellular systems having irregularly shape. The dielectric dispersion of the cell compartments such as nuclear and plasmatic membranes, cytoplasm, nucleoplasm and external medium have been incorporated into the numerical algorithm, too. Moreover, the irregular cell shapes have been modeled by using the Gielis transformations.

Elastic Properties of Rhombus Dodecahedron Open-Cell Cellular Materials

2013 ◽  
Vol 706-708 ◽  
pp. 99-102
Author(s):  
Hong Zhu ◽  
Li Gang Zhang ◽  
Xiang Dong Qi
Keyword(s):  
Elastic Modulus ◽  
Finite Elements ◽  
Relative Density ◽  
Pore Formation ◽  
Geometrical Model ◽  
Cellular Materials ◽  
Curvature Radius ◽  
Open Cell ◽  
Cell Shapes ◽  
Transitional Junction

Based on the principle of pore formation, geometrical model to describe open-cell cellular materials was constructed. The model is rhombus dodecahedron cell shapes with circle-strut and transitional-junction. The dependence of relative density on the microstructure of the model was analyzed; by finite elements method, the relative elastic modulus of the model was calculated, the influence of microstructure and relative density on the elastic modulus was also obtained. The results show that circle-strut radius and transitional-junction curvature radius are the primary factors on relative density increment; nonlinearity of relative density on relative elastic modulus is similar to that of circle-strut radius on relative elastic modulus, is obviously greater than that of transitional-junction curvature radius on relative elastic modulus.

scholarly journals Anti-Acanthamoeba synergistic effect of chlorhexidine and Garcinia mangostana extract or α-mangostin against Acanthamoeba triangularis trophozoite and cyst forms

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Suthinee Sangkanu ◽  
Watcharapong Mitsuwan ◽  
Wilawan Mahabusarakam ◽  
Tajudeen O. Jimoh ◽  
Polrat Wilairatana ◽  
...  
Keyword(s):  
Corneal Stroma ◽  
Good Combination ◽  
Drug Bioavailability ◽  
Garcinia Mangostana ◽  
Minimal Inhibitory Concentrations ◽  
Single Drug ◽  
Cell Shapes ◽  
Amoebic Keratitis ◽  
Irregular Cell ◽  
First Time

AbstractAcanthamoeba spp. can cause amoebic keratitis (AK). Chlorhexidine is effective for AK treatment as monotherapy, but with a relative failure on drug bioavailability in the deep corneal stroma. The combination of chlorhexidine and propamidine isethionate is recommended in the current AK treatment. However, the effectiveness of treatment depends on the parasite and virulence strains. This study aims to determine the potential of Garcinia mangostana pericarp extract and α-mangostin against Acanthamoeba triangularis, as well as the combination with chlorhexidine in the treatment of Acanthamoeba infection. The minimal inhibitory concentrations (MICs) of the extract and α-mangostin were assessed in trophozoites with 0.25 and 0.5 mg/mL, for cysts with 4 and 1 mg/mL, respectively. The MIC of the extract and α-mangostin inhibited the growth of A. triangularis trophozoites and cysts for up to 72 h. The extract and α-mangostin combined with chlorhexidine demonstrated good synergism, resulting in a reduction of 1/4–1/16 of the MIC. The SEM results showed that Acanthamoeba cells treated with a single drug and its combination caused damage to the cell membrane and irregular cell shapes. A good combination displayed by the extract or α-mangostin and chlorhexidine, described for the first time. Therefore, this approach is promising as an alternative method for the management of Acanthamoeba infection in the future.

scholarly journals Synergistic Effect of Garcinia Mangostana Combined With Chlorhexidine on Acanthamoeba Triangularis Trophozoites and Cysts

2020 ◽  
Author(s):  
Suthinee Sangkanu ◽  
Watcharapong Mitsuwan ◽  
Wilawan Mahabusarakam ◽  
Tajudeen O. Jimoh ◽  
Polrat Wilairatana ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Membrane Damage ◽  
Treatment Method ◽  
Synergistic Activity ◽  
Garcinia Mangostana ◽  
Kinetic Assay ◽  
Cell Membrane Damage ◽  
Microdilution Method ◽  
Cell Shapes ◽  
Irregular Cell

Abstract Background: Various parts of Garcinia mangostana Linn, including its pericarp have been traditionally used to treat different types of diseases. This study was carried out to determine the anti-Acanthamoeba activity of G. mangostana pericarp extract against Acanthamoeba triangularis. Methods: The G. mangostana ethanolic pericarp extract was screened for the anti-Acanthamoeba activity and determined its minimal inhibition concentrations (MICs) by the microdilution method. Then, the time-kill kinetic assay of the extract was determined. The synergistic effect of G. mangostana extract and chlorhexidine was performed using the checkerboard method. Parasite morphology was detected by scanning electron microscopy (SEM).Results: The MICs of extract were assessed on trophozoites and cysts with 250 and 4000 µg/mL, respectively. More so, at 2×MIC of extract exhibited inhibitory activity against trophozoites and cyst of A. triangularis for up to 7 days. Checkerboard assays showed synergistic activity of extract (500-1000 μg/mL) plus chlorhexidine (3.90-15.62 μg/mL) at a fractional inhibitory concentration index (FICI) of 0.18-0.37. The lowest FICI (0.18) displayed good synergism resulting in up to 16-fold reduction of drug MIC and reducing to 8-fold of extract MIC. The viability of cysts decreased to 12.28±3.03 cells/mL. FICI interpretation equal to 1 is considered an additive effect on Acanthamoeba trophpzoites. The SEM results clearly showed that Acanthamoeba cells treated with a single drug of chlorhexidine and its combination with G. mangostana extract caused cell membrane damage and irregular cell shapes comparing with the control. Conclusion: A good combinatorial relationship displayed by G. mangostana extract and chlorhexidine suggest a more reliable evidenced based therapeutic strategy. Therefore, this approach is promising and could be employed as an alternative treatment method for the management of Acanthamoeba infection.

scholarly journals Interference with the cytoplasmic tail of gp210 disrupts “close apposition” of nuclear membranes and blocks nuclear pore dilation

2002 ◽  
Vol 158 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Sheona P. Drummond ◽  
Katherine L. Wilson
Keyword(s):  
Pore Formation ◽  
Integral Membrane Protein ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Outer Membranes ◽  
Nuclear Assembly ◽  
Nuclear Membranes ◽  
Pore Dilation ◽  
Pore Complexes ◽  
Lumenal Domain

We tested the hypothesis that gp210, an integral membrane protein of nuclear pore complexes (NPCs), mediates nuclear pore formation. Gp210 has a large lumenal domain and small COOH-terminal tail exposed to the cytoplasm. We studied the exposed tail. We added recombinant tail polypeptides to Xenopus nuclear assembly extracts, or inhibited endogenous gp210 tails using anti-tail antibodies. Both strategies had no effect on the formation of fused flattened nuclear membranes, but blocked NPC assembly and nuclear growth. Inhibited nuclei accumulated gp210 and some nucleoporin p62, but failed to incorporate nup214/CAN, nup153, or nup98 and were defective for nuclear import of lamin B3. Scanning and transmission EM revealed a lack of “closely apposed” inner and outer membranes, and the accumulation of novel arrested structures including “mini-pores.” We conclude that gp210 has early roles in nuclear pore formation, and that pore dilation is mediated by gp210 and its tail-binding partner(s). We propose that membrane fusion and pore dilation are coupled, acting as a mechanism to control nuclear pore size.

Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

1970 ◽  
Vol 28 ◽  
pp. 186-187
Author(s):  
Krishan Awtar
Keyword(s):  
Cell Division ◽  
Normal Cell ◽  
Virus Production ◽  
Multinucleate Cells ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Nuclear Membranes ◽  
Division 2 ◽  
Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

Neuronal and Extraneuronal Uptake of 3H-Norepinephrine in the Heart of the Active Bat: An Electron Microscopic Radioautographic Study

1973 ◽  
Vol 31 ◽  
pp. 522-523
Author(s):  
Martin Hagopian ◽  
Michael D. Gershon ◽  
Eladio A. Nunez
Keyword(s):  
Smooth Muscle ◽  
Monoamine Oxidase ◽  
Vascular Smooth Muscle ◽  
Cardiac Muscle ◽  
Maximum Rate ◽  
External Medium ◽  
Extraneuronal Uptake ◽  
Electron Microscopic ◽  
Cardiac Tissues ◽  
High Affinity

The ability of cardiac tissues to take up norepinephrine from an external medium is well known. Two mechanisms, called Uptake and Uptake respectively by Iversen have been differentiated. Uptake is a high affinity system associated with adrenergic neuronal elements. Uptake is a low affinity system, with a higher maximum rate than that of Uptake. Uptake has been associated with extraneuronal tissues such as cardiac muscle, fibroblasts or vascular smooth muscle. At low perfusion concentrations of norepinephrine most of the amine taken up by Uptake is metabolized. In order to study the localization of sites of norepinephrine storage following its uptake in the active bat heart, tritiated norepinephrine (2.5 mCi; 0.064 mg) was given intravenously to 2 bats. Monoamine oxidase had been inhibited with pheniprazine (10 mg/kg) one hour previously to decrease metabolism of norepinephrine.

Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

1983 ◽  
Vol 41 ◽  
pp. 484-487
Author(s):  
Etienne de Harven
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Spot Size ◽  
Primary Electron ◽  
Critical Point Drying ◽  
Cell Shapes ◽  
High Resolution Images ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

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