Search Results
Results 351 - 400 of 1831
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Miller Morton W - - 2004
The occurrence of cell lysis following exposure to ultrasound (US) has been well documented; the specifics of the mechanistic process(es) involved have proven to be difficult to characterize. There appear to be two major mechanisms of US-induced cell lysis in vitro, acoustic cavitation and bubble transport. Both involve shear forces. ...
Bogé G - - 2004
Red blood cells of marine fish have been used in suitable biological assays to study the (eco)toxicity of wastewater treatment plant effluents. The aim of the present work was to draw upon their more relevant effects on cell hemolysis, ATP content, osmotic resistance and cell volume regulation. Following physico-chemical treatment, ...
Barkley Suzanne - - 2004
It is desirable that cells adsorbed in affinity-separation processes be easily recovered from the adsorption surface, without excessive dilution, once contaminants have been removed. The present study investigates the use of gas-bubble-induced shear stress for the recovery of affinity-adsorbed human erythrocytes. This method has previously been demonstrated to be effective ...
Dolz María - - 2004
BACKGROUND: The Na(+)/H(+) exchanger (NHE) of mammalian cells is an integral membrane protein that extrudes H(+) ion in exchange for extracellular Na(+) and plays a crucial role in the regulation of intracellular pH (pHi). Thus, when pHi is lowered, NHE extrudes protons at a rate depending of pHi that can ...
Chao P Grace - - 2005
Many cells exhibit disparate responses to a mechanical stimulus depending on whether it is applied dynamically or statically. In this context, few studies have examined how cells respond to dynamic changes of the extracellular osmolality. In this study, we hypothesized that the cell size change response of cultured articular chondrocytes ...
Boudreault F - - 2004
Precise measurement of rapid volume changes of substrate-adherent cells is essential to understand many aspects of cell physiology, yet techniques to evaluate volume changes with sufficient precision and high temporal resolution are limited. Here, we describe a novel imaging method that surveys the rapid morphology modifications of living, substrate-adherent cells ...
Wolf Federica I - - 2004
To study the role of Magnesium in the regulation of cell proliferation we characterized the proliferation behaviour of HC-11 mammary epithelial cells that were grown in media containing low to high Mg concentrations. Cells grown under control conditions (0.5 mM Mg in the medium) or in the presence of high ...
Kuchel P W - - 2004
31P magic angle spinning NMR (MAS-NMR) spectra were obtained from suspensions of human red blood cells (RBCs) that contained the cell-volume-sensitive probe molecule, dimethyl methylphosphonate (DMMP). A mathematical representation of the spectral-peak shape, including the separation and width-at-half-height in the 31P NMR spectra, as a function of rotor speed, enabled ...
Bartels Helmut - - 2004
Lampreys, one of the only two surviving groups of agnathan (jawless) vertebrates, contain several anadromous species that, during their life cycle, thus migrate from fresh to seawater and back to freshwater. Lampreys have independently evolved the same overall osmoregulatory mechanisms as the gnathostomatous (jawed) and distantly related teleost fishes. Lamprey ...
Ingram Joanne Helen - - 2004
The response of murine macrophages to clinically relevant polyethylene wear particles generated from different polyethylenes at various time points and volumetric doses in vitro was evaluated. Clinically relevant ultra high molecular weight polyethylene (UHMWPE) wear debris was generated in vitro in a lubricant of RPMI 1640 supplemented with 25% (v/v) ...
Fuster Daniel - - 2004
Sodium/hydrogen exchangers (NHEs) are ubiquitous ion transporters that serve multiple cell functions. We have studied two mammalian isoforms, NHE1 (ubiquitous) and NHE3 (epithelial-specific), by measuring extracellular proton (H+) gradients during whole-cell patch clamp with perfusion of the cell interior. Maximal Na(+)-dependent H+ fluxes (JH+) are equivalent to currents >20 pA ...
Shirgaonkar Irfan Z - - 2004
This article is a review highlighting the application of the acoustic filter as a reliable cell retention device during the long-term perfusion of animal cell cultures. Critical operating parameters such as duty cycle, perfusion and re-circulation flow rates, acoustic power and backflush frequency are discussed with regard to influence on ...
Pedersen Stine Falsig - - 2004
By virtue of their electroneutral exchange of intracellular H+ for extracellular Na+, the Na+/H+ exchangers (NHE1-NHE8) play a pivotal role in many physiological processes. This review focuses on the ubiquitous plasma membrane isoform, NHE1. Particular attention is given to the roles and regulation of NHE1 in erythrocytes, in their own ...
Zhu Jin-Xia - - 2004
AIM: Colonic epithelium is known to secrete both Cl(-) and HCO(3)(-), but the secretory mechanisms of different colonic cell types are not fully understood. The present study aimed to investigate the differential activation of Cl(-) and HCO(3)(-) secretion by tetramethylpyrazine (TMP) in human crypt-like cell line, T84, and villus-like cell ...
Serpe Loredana - - 2004
Cholesteryl butyrate solid lipid nanoparticles (chol-but SLN) have been proposed as a pro-drug to deliver butyric acid. We compared the effects on cell growth, cell-cycle distribution and c-myc expression of chol-but SLN and sodium butyrate (Na-but) in the human leukemic cell lines Jurkat, U937 and HL-60. In all the cell ...
Sartor P - - 2004
Rat lactotrope cells in primary cultures have a higher intracellular Cl- concentration ([Cl-]i) than that predicted by a passive distribution across the membrane. This suggests that active cellular mechanisms ensure this ionic equilibrium. In this study, we examined the interactions between pHi, [Cl-]i regulation and cell energetics. We analyzed: 1. ...
Braunstein Gavin M - - 2004
BACKGROUND: Loss of cystic fibrosis transmembrane conductance regulator (CFTR) function in cystic fibrosis (CF) causes dysregulation of multiple ion channels, water channels, and acid-base transporters in epithelia. As such, we hypothesized that dysregulation of many critical ion channels and transporters may cause defects in human airway epithelial cell volume regulation. ...
Tomassen Sebastian F B - - 2004
In response to osmotic cell swelling, Intestine 407 cells react with a rapid and transient activation of phospholipase D (PLD). To investigate the role of PLD during the regulatory volume decrease, cells were treated with 1-butanol resulting in a depletion of PLD substrates. Activation of volume-regulated anion channels, but not ...
Li Rena R Department of Psychiatry and Behavioral Sciences, University of Louisville School of Medicine, KY 40292, - - 2004
While the pathogenesis of manic-depressive, or bipolar, illness is unknown, an excess of intracellular sodium and calcium concentrations is thought to contribute to the development of the illness. Previous work has demonstrated a reduced adaptive response of the sodium pump to ethacrynic acid in lymphocytes obtained from bipolar subjects compared ...
Dunham Philip B - - 2004
Na+/H+ exchangers (NHE) are widely distributed transporters responsible for regulation of cell volume and pH. In isotonic medium, NHE is often low or negligible, and is strongly activated by osmotic cell shrinkage. It is reported here that extracellular Na+ inhibits NHE in isotonic medium, and cell shrinkage stimulates NHE by ...
Danilewicz Marian - - 2004
Morphometric investigations were performed to determine whether mast cells correlate with tubulointerstitial fibrosis in acute renal transplant rejection (ARTR) and to examine the relationship between mast cells, interstitial alpha-smooth muscle actin (alpha-SMA) expression, and interstitial infiltrates. Twenty-four renal allograft biopsy specimens from patients with ARTR were examined quantitatively by means ...
Wang Li-Wei - - 2004
The immunofluorescence approach, the confocal microscopy and the patch-clamp technique were used to investigate the expression of ClC-3 (one of the candidates of volume-activated chloride channels) and its relationships with the volume-activated chloride current and the capacity of regulatory volume decrease (RVD) in the cell cycle of nasopharyngeal carcinoma cells ...
Grover N B - - 2004
In this article, we examine a large number of combinations of growth models, with separate attention to cell volume, cylindrical surface-area, polar caps, nascent poles, onset of constriction, precision of cell division and interdivision-time dispersion, for Escherichia coli cells growing in steady state at various doubling times. Our main conclusion ...
Wu Karen L - - 2004
Apoptosis results in cell shrinkage and intracellular acidification, processes opposed by the ubiquitously expressed NHE1 Na(+)/H(+) exchanger. In addition to mediating Na(+)/H(+) transport, NHE1 interacts with ezrin/radixin/moesin (ERM), which tethers NHE1 to cortical actin cytoskeleton to regulate cell shape, adhesion, motility, and resistance to apoptosis. We hypothesize that apoptotic stress ...
Contreras R G - - 2004
Abstract. In previous work we described a "P-->A mechanism" that transduces occupancy of the pump ( P) by ouabain into changes in phosphorylation, stimulation of mitogen-activated protein kinase (MAPK), and endocytosis of cell-cell- and cell-substrate-attaching molecules ( A), thereby causing a release of the cell from the monolayer. In the ...
Hegde Manu - - 2004
Previously, we demonstrated that malignant glioma cell lines have increased intracellular pH (pHi) as a result of increased activities of the type I sodium/hydrogen exchanger (NHE1). This alkalotic pHi of 7.2 to 7.4 is favorable for augmented glycolysis, DNA synthesis, and cell cycle progression. Conversely, reductions in pHi have been ...
Millar I D - - 2004
The membrane protein KCNE1 has been implicated in cell volume regulation. Using a knockout mouse model, this study examined the role of KCNE1 in regulatory volume decrease (RVD) in freshly isolated renal proximal tubule cells. Cell diameter was measured using an optical technique in response to hypotonic shock and stimulation ...
Paterson Christopher A - - 2004
In the lens, different cells appear to be specialized such that some have a high capacity for energy-dependent ion transport while others do not. This short review describes the distribution of functional Na,K-ATPase activity and Ca-ATPase activity in the lens. Movement of ions in the extracellular space between lens fibers, ...
Culliford Steve J - - 2004
1. There are no effective ways of screening for potential modulators of volume-regulated anion channels in their native cell type. Generally, cell lines are used for this purpose. Using HeLa and C6 glioma cells, we identified the pyrethroids as a novel class of compounds that inhibit taurine efflux through volume-regulated ...
ZieliƄska Magdalena - - 2004
Treatment of cerebral cortical slices with 5mM ammonium acetate (ammonia) elevated the glutamine (Gln) content and increased cell volume in the slices, in agreement with the postulated contribution of glutamine to hyperammonemic brain edema [Neurochem. Int. 43 (2003) 299]. In this study we show that, unexpectedly, treatment with a glutamine ...
Pedrosa Rui - - 2004
The sensitivity of the Cl(-)/HCO(3)(-) exchanger to dopamine D(1)- and D(2)-like receptor stimulation in immortalized renal proximal tubular epithelial cells from the spontaneous hypertensive rat (SHR) and Wistar-Kyoto rat (WKY) was examined. The activity of the Cl(-)/HCO(3)(-) exchanger (in pH U/s) in SHR cells (0.00191) was greater than in WKY ...
Sennoune Souad R - - 2004
Tumor cells thrive in a hypoxic microenvironment with an acidic extracellular pH. To survive in this harsh environment, tumor cells must exhibit a dynamic cytosolic pH regulatory system. We hypothesize that vacuolar H(+)-ATPases (V-ATPases) that normally reside in acidic organelles are also located at the cell surface, thus regulating cytosolic ...
Yamamoto Shintaro - - 2004
The cell-volume regulation by swelling-activated Cl- current (I(Cl,swell)) was studied in guinea pig ventricular myocytes, using a microscopic video-image analysis. We have previously shown that in ventricular cells depolarized in high-K+ ([K+]o>45 mM) solution, an activation of the cyclic AMP-dependent Cl- current (I(Cl,cAMP)) leads to cell swelling. We first investigated ...
Hawkings Guy S - - 2004
Mitochondria-rich cells (MR cells) of the gills of rainbow trout undergo changes in relative distribution and biochemical function during acclimation to partial-strength (10 per thousand ) and full-strength (30 per thousand ) seawater. In isolated total gill cells, Na(+)/K(+)-ATPase activity increased fivefold and H(+)-ATPase activity decreased fourfold when trout were ...
Nakagawa Ryuji - - 2004
BACKGROUND: It would be beneficial to be able to predict the cord blood (CB) cell yield from volunteer donors before cell processing. STUDY DESIGN AND METHODS: The maternal and neonatal factors that influence the total nucleated cell (TNC), CD34+ cell, and CFU-GM yields in CB collected for the Chugoku-Shikoku Cord ...
Shibata Y - - 2004
Implant surfaces should be modified to achieve excellent cell compatibility as well as antibacterial activity. Our previous study demonstrated that titanium plates anodized by being discharged in NaCl (Ti-Cl) exhibited high antibacterial activity. Since Ti-Cl was prepared with a NaCl solution, we hypothesized that Ti-Cl would exhibit low toxicity toward ...
Leguen Isabelle - - 2004
The effect of hypotonic shock on cultured pavement gill cells from freshwater (FW)- and seawater (SW)-adapted trout was investigated. Exposure to 2/3rd strength Ringer solution produced an increase in cell volume followed by a slow regulatory volume decrease (RVD). The hypotonic challenge also induced a biphasic increase in cytosolic Ca(2+) ...
Rouzaire-Dubois Béatrice - - 2004
The homeostasis of the central nervous system is highly controlled by glial cells and is dramatically altered in the case of glioma. In this respect, the complex connection between cell size and division is of particular importance and needs clarifying. In order to investigate this connection, cell number and volume ...
Zonia Laura - - 2004
Pollen tube cell volume changes rapidly in response to perturbation of the extracellular osmotic potential. This report shows that specific phospholipid signals are differentially stimulated or attenuated during osmotic perturbations. Hypo-osmotic stress induces rapid increases in phosphatidic acid (PA). This response occurs starting at the addition of 25% (v/v) water ...
Golstein P E - - 2004
This study characterized the membrane permeability to cAMP in a cell line derived from the rat colon (CC531(mdr+)) by comparison of fluxes of 3H-cAMP, 3H-8-bromo-cAMP, 3H-taurine, 3H-adenosine and 3H-5'AMP under various experimental conditions including cell membrane depolarization and hypotonic cell swelling. Cell volume was modified by changing the osmolality and ...
Orlov Sergei N - - 2004
Several research teams have proposed that shrinkage and swelling in cells undergoing apoptosis and oncosis are not only the earliest morphological markers of the two modes of cell death but are also obligatory steps in the development of the death machinery. We examined this hypothesis as well as the role ...
da Cunha Lima Marta - - 2004
The presence of morphological differences in the sublingual gland of male and female adult rats was determined by morphometry. Absolute and relative glandular mass was 21% lower and 31% higher, respectively, in females than in males. The fractions of glandular volume occupied by the mixed acini, intercalated ducts and striated ...
Okada Yasunobu - - 2004
All animal cell types have an appropriate volume. Even under physiological conditions of constant extracellular osmolarity, cells must regulate their volume. Cell volume is subjected to alterations because of persistent physicochemical osmotic load resulting from Donnan-type colloid osmotic pressure and of cell activity-associated changes in intracellular osmolarity resulting from osmolyte ...
Srinivas S P - - 2004
PURPOSE: Hyposmolar perfusion of intact trabecular meshwork (TM) induces a decrease in its hydraulic conductivity (Lp). However, exposure to agents that elevate intracellular cAMP in TM cells increases Lp. Since volume of TM cells could directly influence porosity of the TM and hence Lp, this study has investigated changes in ...
Amemiya Morimasa - - 2004
BACKGROUND/AIMS: Chronic hypokalemia increases NHE3 activity in OKP cells. The aim of the present study was to determine whether an autocrine mechanism is involved in this activation. METHODS: After incubation of OKP cells in normal-K(+) and low-K(+) media for 24 h, the potassium concentration in the low-K(+) media was adjusted ...
Capaldo A - - 2004
The existence of paracrine control of steroidogenic activity by adrenochromaffin cells in Triturus carnifex was investigated by in vivo noradrenaline (NA) administration. The effects were evaluated by examination of the ultrastructural morphological and morphometrical features of the tissues as well as the serum levels of aldosterone, NA, and adrenaline (A). ...
Ordaz Benito - - 2004
A decrease in external osmolarity results in cell swelling and the immediate activation of a mechanism to restore cell volume, known as regulatory volume decrease (RVD). When exposed to a gradual osmolarity decrease (GODE), some cells do not swell. This reflects the operation of an active regulatory process known as ...
Guadalupe Cabral M - - 2004
AIMS: The objective of this work was to examine adaptative responses occurring in Saccharomyces cerevisiae following exposure to the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA). METHODS AND RESULTS: The exposure of a yeast cell population to MCPA concentrations of moderate toxicity led to a period of latency before eventual resumption of inhibited ...
Lin Chia-Hao - - 2004
Changes in expression of Na, K-ATPase (NKA) and morphometry of mitochondrion-rich (MR) cells in gills of tilapia were investigated on a 96-hr time course following transfer from seawater (SW) to fresh water (FW). A transient decline in plasma osmolality and Na+, Cl- concentrations occurred from 3 hrs onward. Gills responded ...
Lambert Ian Henry - - 2004
Change in the intracellular concentration of osmolytes or the extracellular tonicity results in a rapid transmembrane water flow in mammalian cells until intracellular and extracellular tonicities are equilibrated. Most cells respond to the osmotic cell swelling by activation of volume-sensitive flux pathways for ions and organic osmolytes to restore their ...
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