Conclusion
Nate F. Cardarelli in Tin as a Vital Nutrient:, 2019
It is well recognized that the tumor cell membrane possesses properties different from that of the normal cell.63 There is an asocial tissue organization,64 perhaps characterized by a lack of cell to cell communication.65,66 Cellular adhesiveness is altered and the contact inhibition mechanism is defective.67–70 Electrophoretic mobility is altered.63,71 The membrane surface electric charge density may be different from that of a normal cell,72 although there are indications to the contrary.73 The plasmalemma carries new antigens, some of which are embryonic, and loses organ-specific antigens.74–76 The cell membrane has an altered chemical structure77,78 which leads to abnormal permeability to enzymes and other substances.79 Ultracellular changes are also noted both in the morphological sense and in terms of energy production systems.63 The time of the mitotic cycle is much reduced in tumor cells,80 although a progressive increase in duration of the cell cycle is noted as a function of tumor age.81
E
Anton Sebastian in A Dictionary of the History of Medicine, 2018
Electrophoresis A process of analysis based on the mobility of different substances in an electric field. Described by Arne Wilhelm Tiselius (1902–1971) of Stockholm in 1930. It was simplified in 1944 by Richard Laurence Millington Synge (1914), A.H. Gordon and John Porter Archer who used water on cellulose (filter paper) as a medium. Charles Dent, professor of metabolism at the University of London, used the technique to identify 60 different amino acids in 1948. Gel electrophoresis was used to assay the variation in protein sequences by NewYork geneticist, Richard Charles Lewontin (b 1929), in 1966. Pulse field gel electrophoresis for separation of large DNA molecules was developed by another NewYork geneticist, Charles Robert Cantor (b 1942) at the University of California, Berkeley. His method became an essential tool in the study of DNA in chromosomes.
Nonhistone Nuclear Phosphoproteins
Lubomir S. Hnilica in Chromosomal Nonhistone Proteins, 2018
Recently, Mamrack et al.143,144 found phosphorylation sites within clusters of acidic amino acids in two nonhistone proteins, C23 and B23. Table 4 indicates that three sites of phosphorylation are present in an acidic region of protein C23. The tryptic peptide (C23Ca) which contains these sites is present in three electrophoretic forms. Figure 9 illustrates that the electrophoretic mobility at pH 1.8 is directly proportional to the number of phosphoryl groups or the net negative charge of the molecule. At this pH the carboxyl groups are unionized so that the net charge of the molecule is determined only by the amino groups and phosphoryl groups. Thus, in peptides with multiple phosphorylation sites the electrophoretic mobility at low pH is a useful parameter in determining the level of phosphorylation.
Iontophoresis for the cutaneous delivery of nanoentraped drugs
Published in Expert Opinion on Drug Delivery, 2023
Jayanaraian F. M. Andrade, Marcilio Cunha-Filho, Guilherme M. Gelfuso, Tais Gratieri
Electrophoretic mobility is related to the mass-to-charge ratio of the molecules and impacts EM contribution [88]. In some cases, the charge cannot compensate for a molecule’s weight, as shown in a study investigating the influence of weight and density charge of peptide dendrimers in skin penetration. The study concluded that doubling the charge density did not compensate for the double size of dendrimers during skin permeation tests [89]. In a different case, the combination of lysine peptide dendrimers with iontophoresis offered greater enhancement when the dendrimer with the lowest molecular weight and highest charge density (MW: 822.51, charge: 4+) was employed. As a result, ketoprofen penetration into the skin increased 7-fold compared to the free drug passive administration. This dendrimer also showed to deliver ketoprofen to the plasma in therapeutical concentrations (985.46 ± 43.25 ng/mL) under iontophoretic transport [90].
Antinociceptive synergistic interaction between Achillea millefolium and Origanum vulgare L. extract encapsulated in liposome in rat
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Farshad Hassanzadeh-kiabi, Babak Negahdari
Particle size and size distribution are the main parameters used for the assessment of nanoparticles physical stability. The dynamic light scattering (DLS) is extensively used to assess the size and size distribution of small particles suspended in liquid medium. The mean particle size, size distribution, and polydispersity index (PDI) are the main parameters of this technique. A PDI value that falls between 0.1 and 0.25 shows a narrow size distribution, while a PDI >0.5 shows a broad size distribution [16]. Although the DLS method provides fast measurement of size distribution and particle size, they are not competence in assessing particle morphology similarly to direct visualization method like microscopy. Laser Doppler electrophoresis is a technique often employed to measure zeta potential. It evaluates electrophoretic mobility of suspended particles in the medium. It is an overall rule of thumb that an absolute value of zeta potential >60 mV gave a good stability, value of 30 mV usually results in good stability, 20 mV is acceptable short-term stability, and <5 mV means rapid particle aggregation [16].
Surface properties of Enterococcus faecalis cells isolated from chicken hearts determine their low ability to form biofilms
Published in Biofouling, 2018
Jolanta Cieśla, Dagmara Stępień-Pyśniak, Agnieszka Nawrocka, Małgorzata Łukowska, Tomasz Hauschild, Andrzej Wernicki, Andrzej Bieganowski
Each of the electrophoretic mobility measurements was preceded by the determination of particle size distribution. The apparatus used dynamic light scattering (DLS) for particle size determination in colloidal systems. The Brownian motions of the particles that are dispersed in liquid cause fluctuation of the intensity of scattered light. An autocorrelator creates the autocorrelation function of signal, which decreases exponentially with time. The speed of decay of the autocorrelation function is proportional to the apparent diffusion coefficient (D), the value of which is related to the particle size by the Stokes–Einstein formula: D = kT/3πηdh, where k is the Boltzmann constant, T is the absolute temperature, η is the solvent viscosity, and dh is the hydrodynamic diameter of the particle (ISO 13321 1996). A general-purpose model was used for data processing. Measurements were taken at the same optical parameters and temperature that were used for determining the electrophoretic mobility. The mean hydrodynamic diameter was obtained from six repetitions. Additionally, the mean particle size distribution by the intensity of scattered light (from six measurements) was analysed according to the location of the peaks. The quicker the diffusion, the smaller the particle size, which is determined by the DLS method (ISO 13321 1996). Live bacteria can possess appendages that makes their motion in liquid faster than when it occurs only via Brownian motion. Consequently, their cell size determined by DLS can be lower than the real value. Taking this into consideration, the DLS results obtained were used only as indicators of change in bacterial cell size caused by autoclaving. Additionally, all the analysed bacterial suspensions at OD620 = 0.059 were imaged using an optical microscope (Olympus BX41, New York Microscope Company Inc., Hicksville, NY, USA).
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