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Biochemistry, Biophysics, and Structural Biology Commons

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Articles 1 - 9 of 9

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 Nov 1989

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 Nov 1989

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.


A Lipopolysaccharide-Induced Dna-Binding Protein For A Class Ii Gene In B Cells Is Distinct From Nf-Kappa B, Ellen M. Gravallese, Mark R. Boothby, Cynthia M. Smas, Laurie H. Glimcher Aug 1989

A Lipopolysaccharide-Induced Dna-Binding Protein For A Class Ii Gene In B Cells Is Distinct From Nf-Kappa B, Ellen M. Gravallese, Mark R. Boothby, Cynthia M. Smas, Laurie H. Glimcher

Rheumatology Publications and Presentations

Class II (Ia) major histocompatibility complex molecules are cell surface proteins normally expressed by a limited subset of cells of the immune system. These molecules regulate the activation of T cells and are required for the presentation of antigens and the initiation of immune responses. The expression of Ia in B cells is determined by both the developmental stage of the B cell and by certain external stimuli. It has been demonstrated previously that treatment of B cells with lipopolysaccharide (LPS) results in increased surface expression of Ia protein. However, we have confirmed that LPS treatment results in a significant ...


Turning Eggs To Fossils: A Natural Experiment In Taphonomy, James Hayward, Charles Amlaner, Karen Young May 1989

Turning Eggs To Fossils: A Natural Experiment In Taphonomy, James Hayward, Charles Amlaner, Karen Young

Charles J. Amlaner

Ashfall from Mount St. Helens' May 18, 1980 eruption covered eggs and nests of two species of colonial, ground-nesting gulls. While some members of both species excavated their eggs from beneath the ash, most eggs and nests remained buried. One year after the ashfall, habitats known to contain pre-ashfall nests were transected and the ash layer was measured and removed. Eggs, nests, and associated materials were counted. Entire hollow eggshells and eggshell fragments were found, as well as rodent bones and teeth, bird bones, beetle carapaces, and vegetation. No fetal bones were found with eggs. Fossilization potential for nests and ...


The Physiology And Biochemistry Of Isolated Skeletal Muscle Mitochondria : A Comparative Study, Mark Lowell Wagner Jan 1989

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 ...


A Practical Workshop On Biotelemetry, E. Smith, Charles Amlaner Dec 1988

A Practical Workshop On Biotelemetry, E. Smith, Charles Amlaner

Charles J. Amlaner

No abstract provided.


Avian Sleep, Charles Amlaner, Nigel Ball Dec 1988

Avian Sleep, Charles Amlaner, Nigel Ball

Charles J. Amlaner

No abstract provided.


Biotelemetry X: Proceedings Of The Tenth International Symposium On Biotelemetry, Charles Amlaner (Editor) Dec 1988

Biotelemetry X: Proceedings Of The Tenth International Symposium On Biotelemetry, Charles Amlaner (Editor)

Charles J. Amlaner

Proceedings of the Tenth International Symposium on Biotelemetry, held in Fayetteville, Arkansas, on July 31 to August 5, 1988.


Electrophysiological Sleep Characteristics In Bobwhite Quail, Douglas Schmidt, James Shaffery, Nigel Ball, D. Loenneke, Charles Amlaner Dec 1988

Electrophysiological Sleep Characteristics In Bobwhite Quail, Douglas Schmidt, James Shaffery, Nigel Ball, D. Loenneke, Charles Amlaner

Charles J. Amlaner

No abstract provided.