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Articles 1 - 5 of 5
Full-Text Articles in Biochemistry, Biophysics, and Structural Biology
Presence Of A Cs-Resistant Transient Outward Current Which Distorts Ica Measurements In Guinea-Pig Single Ventricular Cells, Georges Christé, Brigitte Delachapelle, Fouad Lemtiri-Chlieh, Carlos Ojeda
Presence Of A Cs-Resistant Transient Outward Current Which Distorts Ica Measurements In Guinea-Pig Single Ventricular Cells, Georges Christé, Brigitte Delachapelle, Fouad Lemtiri-Chlieh, Carlos Ojeda
fouad Lemtiri-Chlieh
To correctlyr analyse the physical properties of ion channels and the actions of drugs upon them, it is important that the membrane conducts only the ionic species believed permeant. In guinea-pig ventricular cells it has been assumed that only ICaL flows in the potential range -50 to +60 mV in the presence of intra- and extracellular Cs (> 20 mM). We report here that this is not the case due to the presence of a Cs-insensitive, transient outward current.
Measurements Of Cytosolic Free Ca In Cultured Rat Neonate And Adult Guinea-Pig Ventricular Cardiac Myocytes, Jean-Claude Bernengo, Fouad Lemtiri-Chlieh, Carlos Ojeda, Nadine Pltonoff
Measurements Of Cytosolic Free Ca In Cultured Rat Neonate And Adult Guinea-Pig Ventricular Cardiac Myocytes, Jean-Claude Bernengo, Fouad Lemtiri-Chlieh, Carlos Ojeda, Nadine Pltonoff
fouad Lemtiri-Chlieh
Cytosolic free Ca was measured with Indo-1 (Grynkiewicz et al. 1985) as free acid (in guinea-pig cells) or as the ester (in rat neonate cells). Using image analysis we obtained concentration maps at 40 ms intervals at two wavelengths (Cannell et al. 1986). In rat neonate cells, at rest and during contraction, calcium was apparently non-uniformly distributed, in contrast to guinea-pig adult cells. Using a dual PM spectroscopic system adapted to an inverted microscope we found: (1) the conversion of Indo-AM to Indo- 1 in the cytosol is not complete (< 40% contribution to the total light); (2) rat neonate cells buffer Ca (at rest 130-170 nM) only for [Ca]. between 1 and 3 mM, whereas in adult guinea-pig cells the range extended to 10 mM; (3) during contraction [Ca]i rose from 200 nm to no more than 1 microM. Digitoxin increases basal and peak [Ca]i; (4) during spontaneous contractions, in guinea-pig cells, [Ca]i rises from 70 to 200 nm when [Ca]o = 0, and from 170 nm to about 1 microM when [Ca]o = 2 mM; (5) in voltage-clamp conditions the rise in [Ca]i does not exceed 2 microM and oscillations occur in the presence of forskolin. When loading with Indo-1, cells frequently cease to contract (Powell et al. 1988) and the variations in [Ca]i are then very small (about 200 nm at peak ICa). In both cases these values are small compared to the total charge crossing the membrane.
Spectroscopic Study Of Decomposition Products Of Gossypol, David Bernard Hankins
Spectroscopic Study Of Decomposition Products Of Gossypol, David Bernard Hankins
Chemistry & Biochemistry Theses & Dissertations
Basic research into reproductive physiology has begun to identify possible new approaches to controlling fertility. Gossypol, a natural polyphenol compound isolated from cottonseed oil, has been shown to be an effective male antifertility agent. The decomposition products of gossypol which are thought to possess more potent antifertility effects than the parent compound gossypol have been studied extensively in more recent research. The purpose of this research is to develop techniques and methods which could be used to identify decomposition products of gossypol. A model decomposition reaction by which a smaller molecule can be isolated in a pure state has been …
Regulation Of Epidermal Growth Factor Receptor Synthesis By Retinoic Acid And Dexamethasone, Kerby C. Oberg
Regulation Of Epidermal Growth Factor Receptor Synthesis By Retinoic Acid And Dexamethasone, Kerby C. Oberg
Loma Linda University Electronic Theses, Dissertations & Projects
Fetal rat lung (FRL) cells incubated in the presence of retinoic acid or dexamethasone exhibit altered 125I-epidermal growth factor (EOF) binding capacity. Retinoic acid enhances 125I-EGF binding 3-fold following 24 hours of 37° incubation. In contrast, FRL cells incubated in the presence of dexamethasone display a 2-fold reduction in 125I-EGF binding capacity. The change in binding capacity, induced by either hormone, was due to alterations in the average number of receptors per cell as determined by Scatchard analysis of 125I-EGF binding. In the absence of retinoic acid or dexamethasone, FRL cells were calculated to have approximately …
The Physiology And Biochemistry Of Isolated Skeletal Muscle Mitochondria : A Comparative Study, Mark Lowell Wagner
The Physiology And Biochemistry Of Isolated Skeletal Muscle Mitochondria : A Comparative Study, Mark Lowell Wagner
Dissertations and Theses
The physiological limit to maximum aerobic capacity (VO2max) in vertebrates has been attributed to cardiovascular oxygen delivery, to the ability of the muscle cells to consume oxygen, or to a fine-tuned development of all components of the respiratory system such that no single component can be shown to limit VO2max. The above hypotheses have each been developed using different experiments with different animals. The comparative studies uniting these animals and methods are limited. In order to further our knowledge of the cellular limit to VO2max, skeletal muscle mitochondria were isolated from species representing four …