Cell surface, effect

Wngard, Jr., L. B., T. R. Tritton, and K. A. Egler. 1985. Cell surface effect of adriamycin and carminomycin immobilized on cross-linked polyvinyl alcohdDancer Res45 3529-3536. 

P-Endorphin. A peptide corresponding to the 31 C-terminal amino acids of P-LPH was first discovered in camel pituitary tissue (10). This substance is P-endorphin, which exerts a potent analgesic effect by binding to cell surface receptors in the central nervous system. The sequence of P-endorphin is well conserved across species for the first 25 N-terminal amino acids. Opiates derived from plant sources, eg, heroin, morphine, opium, etc, exert their actions by interacting with the P-endorphin receptor. On a molar basis, this peptide has approximately five times the potency of morphine. Both P-endorphin and ACTH ate cosecreted from the pituitary gland. Whereas the physiologic importance of P-endorphin release into the systemic circulation is not certain, this molecule clearly has been shown to be an important neurotransmitter within the central nervous system. Endorphin has been invaluable as a research tool, but has not been clinically useful due to the avadabihty of plant-derived opiates. 

Computer simulations of bulk liquids are usually performed by employing periodic boundary conditions in all three directions of space, in order to eliminate artificial surface effects due to the small number of molecules. Most simulations of interfaces employ parallel planar interfaces. In such simulations, periodic boundary conditions in three dimensions can still be used. The two phases of interest occupy different parts of the simulation cell and two equivalent interfaces are formed. The simulation cell consists of an infinite stack of alternating phases. Care needs to be taken that the two phases are thick enough to allow the neglect of interaction between an interface and its images. An alternative is to use periodic boundary conditions in two dimensions only. The first approach allows the use of readily available programs for three-dimensional lattice sums if, for typical systems, the distance between equivalent interfaces is at least equal to three to five times the width of the cell parallel to the interfaces. The second approach prevents possible interactions between interfaces and their periodic images. 

A method of assessing the toxicity of implants has been proposed based on the effects on cell ultrastructure in organ cultures, on cell surface characteristics, and cell population doubling times. The effects have been correlated with hemorrhage, fibrosis, and necrosis, respectively (103). Poly-e-caprolactone was stated to give minimal tissue reaction and could not be scored in these tests. 

Effect on the cell surface 4 Semi-solid antibacterial preparations... 

Before an antibacterial agent can exert its effect on a cell it must eombine with that eell. This process often follows the pattern of an adsorption isotherm. Clearly, faetors whieh affect the state of the cell surface, as the pH of the eelTs environment must do, must affect, to some extent, the adsorption process. An inerease in the external pH renders the cell surface more negatively charged. Bioeidal agents that are eationie in nature thus bind more strongly to the cell surface with a eonsequent inerease in aetivity. 

Jyonouchi, H. et al., Studies of immunomodulating actions of carotenoids. I. Effects of P-carotene and astaxanthin on murine lymphocyte functions and cell surface marker expression in in vitro culture system, Nutr. Cancer, 19, 93, 1991. 

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