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Results 701 - 750 of 1831
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Sud'ina G F - - 1998
Upon an increasing cell density human neutrophils develop more cell-to-cell contacts in conjunction with an increase in the pHi. These changes are accompanied by decreased superoxide formation after adherence, and a decrease in the total amount of 5-lipoxygenase products after various stimuli. Among the various arachidonate metabolites, leukotriene formation remained ...
Roussa E - - 1998
Using antibodies against the 31-kD and 70-kD subunits of vacuolar type H+-ATPase (V-ATPase) and light microscopic immunocytochemistry, we have demonstrated the presence of this V-ATPase in rat submandibular gland. We have also investigated the adaptive changes of this transporter during acid-base disturbances such as acute and chronic metabolic acidosis or ...
Perry S F - - 1998
The gill lamellar epithelium is composed of two predominant cell types, pavement cells and mitochondria-rich chloride cells. The chloride cells play a vital role in ionic regulation because they are the sites of Ca2+ and Cl- uptake from water. Consequently, lamellar chloride cell proliferation occurs in response to ionoregulatory challenges ...
Schaffer S W - - 1998
Taurine is a very important organic osmolyte in most adult cells. Because of this property it has been proposed that large changes in the intracellular content of taurine can osmotically stress the cell, causing changes in its size and shape. This hypothesis was examined by measuring cell dimensions of taurine ...
Davis D P - - 1998
Paramecium are attracted to ammonium chloride solutions relative to sodium chloride control solutions, but little is known about the mechanisms by which attraction is evoked. A known effect of ammonium solutions in other cell types is an alteration of intracellular pH. We show here that intracellular pH is elevated upon ...
Lang F - - 1998
Mammalian cells utilize a wide variety of cell volume regulatory mechanisms. For rapid adjustment of cell volume cells release or accumulate ions through respective channels and transport systems across the cell membrane. The most widely used mechanisms of cell volume regulatory ion release include ion channels and KCl symport. Ion ...
Vitushkin A L - - 1998
A design of a multipass optical cell is proposed. This design is based on the use of corner-cube retroreflectors arranged opposite to parallel axes, an incident beam that enters off the plane that contains the axes of the retroreflectors, and right-angle prisms to return to the cell the beam that ...
Miley H E - - 1998
This study investigated regulatory volume increase (RVI) in rat pancreatic beta-cells. Volume changes in isolated beta-cells were measured by a video-imaging method. Cell shrinkage was induced by exposure to solutions made hypertonic by the addition of 100 mM mannitol. In HEPES-buffered solutions, beta-cells exhibited an RVI which was almost completely ...
Jackson P S - - 1997
Cellular use of small organic solutes known as organic osmolytes for regulation of the volume of the cell is a universal biological phenomenon. During swelling, cells open an anion channel which allows for efflux of these solutes. This channel is known as the volume-sensitive organic osmolyte/anion channel (VSOAC). Anion channels ...
Chou C Y - - 1997
1. Previous studies demonstrate that volume-sensitive chloride currents are distinctly activated in cervical cancer cells, but not in human papillomavirus (HPV)-immortalized and normal cervical cells. In the present study, the Na(+)-independent volume-activated transport of taurine in three cervical cell types was investigated. 2. Osmotic swelling of cervical cancer HT-3 cells ...
Civan M M - - 1997
The aqueous humor of the eye is secreted by the bilayered ciliary epithelium, consisting of the pigmented (PE) cell layer facing the stroma and the nonpigmented (NPE) cell layer facing the aqueous humor. Cells within each layer and between the two layers are linked by gap junctions, forming a ciliary ...
Owen C S - - 1997
Intracellular pH (pHi) homeostasis is crucial to cell survival. Cells that are chronically exposed to a low pH environment must adapt their hydrogen ion extrusion mechanisms to maintain their pHi in the physiologic range. An important component of the adaptation to growth at low pH is the upregulation of pHi ...
Cantiello H F - - 1997
The actin cytoskeleton is an intracellular structure, which is involved in the onset and control of cell shape and function. In order for this relevant network to control its own and thus cell volume, specific interactions between the actin cytoskeleton and ion channel regulation controlling intracellular salt and water homeostasis ...
Seo J T - - 1997
To investigate the role of Cl- in the regulation of the basolateral transporters of salivary acinar cells, we have measured cell volume and intracellular pH (pHi) in perfused rat mandibular glands using proton NMR spectroscopy and BCECF fluorometry respectively. When perfusate Cl- was replaced by glucuronate, isethionate, methylsulphate, nitrate or ...
Pelc R - - 1997
We present a new design for a sub-microlitre chamber which enables perfusion of individual cells. No equipment is required for it to be operational, as the exchange of solutions in the chamber is driven solely by capillary forces. Its active volume consists of a 30-micron-thin layer between two coverslips (separated ...
Duan D - - 1997
A volume-regulated chloride current (ICl.vol) is ubiquitously present in mammalian cells, and is required for the regulation of electrical activity, cell volume, intracellular pH, immunological responses, cell proliferation and differentiation. However, the molecule responsible for ICl.vol has yet to be determined. Although three putative chloride channel proteins expressed from cloned ...
Payne J A - - 1997
The neuronal K-Cl cotransporter isoform (KCC2) was functionally expressed in human embryonic kidney (HEK-293) cell lines. Two stably transfected HEK-293 cell lines were prepared: one expressing an epitope-tagged KCC2 (KCC2-22T) and another expressing the unaltered KCC2 (KCC2-9). The KCC2-22T cells produced a glycoprotein of approximately 150 kDa that was absent ...
Ishikawa E - - 1997
The capacitance of suspensions of cultured rice cells (Oryza sativa L. ssp. japonica), grape cells (Vitis sp.), and CH27 cells originated from murine B-cell lymphoma was measured in the frequency range of 0.2 to 10 MHz. The relationship between the increase in capacitance caused by the presence of cells at ...
Deppe C E - - 1997
We investigated the influence of cyclosporine A (CsA) on key plasma membrane ion transport systems Na+/K(+)-ATPase, Na+/K+/2Cl- cotransporter, and H+/K(+)-ATPase in MDCK cells and two subtypes, C7 and C11, serving as a model system to study principal (C7) and intercalated (C11) cell properties of the distal nephron. The transport activity ...
Han B - - 1997
BACKGROUND & AIMS: Changes in cell volume have been recently identified as modulators of cell function and gene expression. This study evaluated the regulation of exocrine secretion by pancreatic acini on the basis of changes in cell hydration. METHODS: Acini were exposed to hypotonicity or hypertonicity. The effects of corresponding ...
Kelly S M - - 1997
Elastic properties of Xenopus oocytes were examined by measuring intracellular pressure (Pic) and cell volume (Vc) in cells undergoing osmotic swelling. Pic was measured by micropuncture, using the servo-null technique. Vc was obtained by analyzing images acquired from a microscope having a video camera attachment. During osmotic swelling, Pic increased ...
Wang H - - 1997
The Na+/H+ exchanger is a ubiquitous plasma membrane protein that is responsible for pH regulation and is activated by growth factors. We examined the role of the Na+/H+ exchanger in cell growth and differentiation. Treatment of P19 cells with the Na+/H+ exchanger inhibitor Hoe 694 eliminated retinoic acid-induced differentiation in ...
Marcussen M - - 1997
The conversion to corresponding triphosphate derivatives of various ribonucleosides has been studied in Ehrlich ascites tumor cells and in Chinese hamster ovary cells under conditions that are optimal for cellular uptake of orthophosphate. The initial cellular uptake of orthophosphate is followed by a cellular loss of Cl- which might be ...
Mairbäurl H - - 1997
A reduced cation reabsorption across the alveolar epithelium decreases water reabsorption from the alveoli and could diminish clearing accumulated fluid. To test whether hypoxia restricts cation transport in alveolar epithelial cells, cation uptake was measured in rat lung alveolar type II pneumocytes (AII cells) in primary culture and in A549 ...
Amlal H - - 1997
The response of H+-ATPase to lethal acid stress is unknown. A mutant strain (called NHE2d) was derived from cultured inner medullary collecting duct cells (mIMCD-3 cells) following three cycles of lethal acid stress. Cells were grown to confluence on coverslips, loaded with 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, and monitored for intracellular pH (pHi) recovery ...
Gunin A G - - 1997
The aim of this study was to examine the role of heparin in the realization of oestradiol (OE2) effects in the uterus. Ovariectomized rats were treated with a single injection of OE2 dipropionate (10 micrograms/rat, i.m.) along with injections of heparin (in doses of 0.4 mg/rat, i.m.). OE2 effects in ...
Carswell M C - - 1997
The influence of the anti-fungal agent phosphonate (Phi) on the response of oilseed rape (Brassica napus L. cv. Jet Neuf) cell suspensions to inorganic phosphate (Pi) starvation was examined. Subculture of the cells for 7 d in the absence of Pi increased acid phosphate (APase; EC 3.1.3.2) and pyrophosphate (PPi)-dependent ...
Obermüller N - - 1997
Despite the recent positional cloning of genes responsible for autosomal dominant polycystic kidney disease (ADPKD), the exact pathogenetic mechanisms underlying this disorder are still unclear. To learn more about cyst formation, we investigated cell differentiation and cell polarity in the Han:SPRD (cy/+) rat between 21 days and 60 wk of ...
de Toledo F G - - 1997
All-trans-retinoic acid (atRA) is a regulator of cellular growth and differentiation. We investigated whether atRA can upregulate Na(+)-dependent cotransporters in opossum kidney (OK) cells and thus increase uptake from tubular fluid of several solutes needed for growth during early stages of ontogenesis. In OK cells, incubation with atRA for 24 ...
Roman R M - - 1997
In a model liver cell line, recovery from swelling is mediated by a sensitive autocrine pathway involving conductive release of ATP, P2 receptor stimulation, and opening of membrane Cl- channels (Wang, Y., Roman, R. M., Lidofsky, S. D., and Fitz, J. G. (1996) Proc. Natl. Acad. Sci. U. S. A. ...
Staub F - - 1997
The therapeutical efficacy of alpha-trinositol (D-myo-inositol-1,2,6-trisphosphate), an isomer of the intracellular messenger IP3, was analyzed on cytotoxic swelling and damage of glial cells in vitro from lactacidosis or glutamate. C6 glioma cells suspended in a physiological medium were either exposed to pH 5.0 by administration of lactic acid, or to ...
Tripathi R K - - 1997
In dengue type 2 virus (DV)-induced suppressor T cell cascade TS1 cells secrete a suppressor cytokine (SF) which acts via syngeneic macrophages (M phi) to recruit TS2 cells. SF binds to both high and low affinity receptors (SF-R) on M phi. In the present study the fate of SF in ...
Richmond P H - - 1997
Intracellular pH (pHi) was measured in enzymically isolated, neonatal rat carotid body type-1 cells, using the fluorophore carboxy-SNARF-1 (AM-loaded), and using the nigericin technique for in situ fluorescence calibration (nigericin is a membrane-soluble K+-H+ exchanger). In CO2/HCO3--free media, inhibiting Na+-H+ exchange produced a prompt fall of pHi (background acid-loading), the ...
Guntupalli J - - 1997
Studies in rat and rabbit outer medullary collecting duct of inner stripe origin (OMCDis) suggest that both H(+)-ATPase and H(+)-K(+)-ATPase participate in H+ secretion. However, the relative contributions of these transporters, and, in particular, that of H(+)-K(+)-ATPase to K+ absorption have not been defined precisely. The present study was designed ...
Schlatter E - - 1997
The imidazoline receptor agonist moxonidine has been recently introduced as an antihypertensive therapy. Imidazoline specific binding sites have also been found in the kidney. Moxonidine induced natriuresis and diuresis in clearance studies in rats. Related substances such as various guanidinium derivatives have been shown to inhibit Na+/H+ exchange in several ...
Häussinger D - - 1997
Liver cells possess potent mechanisms to maintain their volume, i.e., their hydration state. These volume-regulatory mechanisms, however, are apparently not designed to maintain absolute cell volume constancy; they rather act as dampeners to prevent excessive cell volume deviations, which would otherwise result from cumulative substrate uptake or anisotonic stress. Furthermore, ...
Toyomoto T - - 1997
In freshly dissociated rhesus palm eccrine clear cells, regulatory volume increase (RVI) was studied using image analysis as a measure of Na-K-2Cl cotransport activity. Pseudo-RVIs, as well as RVI during methacholine (MCh)-induced cell shrinkage, were observed in clear cells and were inhibited by 100 microM bumetanide or in Na-free medium, ...
Oyama M - - 1997
We found that Dictyostelium amebas shrank about 50% in 10 min after a change in extracellular osmolarity from 70 mosM to 170-370 mosM. Cells shrunk by the addition of 0.1 M mannitol showed a partial recovery of cell volume in 2 h when the culture medium contained salts. A full ...
Malnic G - - 1997
The mechanism of acidification in the cortical distal tubule of mammalian kidney was analysed by "in vivo" microperfusion and using MDCK cells in culture, by electrophysiological and by cell pH microfluorescence techniques. An electrogenic effect of the vacuolar H(+)-ATPase, which has been localized to the intercalated cells of the cortical ...
Lew W Y - - 1997
The effects of 10 ng/ml of lipopolysaccharide (LPS) on cell volume were examined in rabbit left ventricular myocytes. The myocytes were isolated with depyrogenated digestive enzymes (< 0.7 ng/ml of LPS) to minimize tolerance. Myocyte cross-sectional area (CSA) did not change after 1 h of LPS. However after 8 h, ...
Yanagawa N - - 1997
The aim of our study is to examine the effect of intracellular pH (pHi) on inorganic phosphate (Pi) uptake by a proximal tubular cell line, the opposum kidney (OK) cells. The OK cell pHi (7.48 +/- 0.02; n = 12) was altered to levels between 6.5 and 8.5 by the ...
Emma F - - 1997
Regulation of the volume sensitivity of the swelling-activated organic osmolyte/anion channel VSOAC by intracellular electrolytes was examined in intact and patch-clamped C6 glioma cells. In intact cells, VSOAC activation was monitored by [3H]taurine efflux measurements, and intracellular electrolyte concentrations were manipulated by acclimation to hypertonic medium for varying periods of ...
Van Driessche W - - 1997
The effects of gradually reducing the osmolality of the basolateral solution (pi b) were examined in a renal epithelial cell line (A6). pi b was linearly decreased with time from 260 to 140 mosmol/ kgH2O. Cell volume did not change when pi b was gradually decreased at dilution rates (D(r)) ...
Speake P F - - 1997
The effect of urea and its interactions with oxygen tension (PO2), cell volume and inhibitors of protein phosphatases/kinases (PP/PK) on the K influx into equine red blood cells were studied. K influx was measured using 86Rb as a radioactive tracer for K. As in other species, Cl-dependent K influxes were ...
Ballatori N - - 1997
The mechanism by which nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, prevents swelling-activated organic osmolyte efflux was examined in the human hepatoma cell line Hep G2. When swollen in hypotonic medium, Hep G2 cell exhibited a regulatory volume decrease that was associated with the release of intracellular taurine, an amino acid ...
Nakahari T - - 1997
The effects of terbutaline (a selective beta 2-adrenoceptor agonist) on cell volume and ion transport in rat fetal distal lung epithelial (FDLE) cells were studied. In FDLE cells, benzamil (1 microM) induced cell shrinkage, while cell volume was increased by 1 mM quinine or 2 mM Ba2+ but was not ...
Mayhew T M - - 1997
The availability of design-based stereological methods has made it possible to readdress certain key and contentious issues in placental growth and morphogenesis. Three particular questions are: (i) does the population of cytotrophoblast cells decline during gestation?, (ii) is placental growth biphasic or monophasic? and (iii) what are the consequences for ...
Miwa A - - 1997
The possible correlation between P-glycoprotein (PGP) and volume-sensitive Cl- channel was examined in a pair of cell lines: a subline of the human epidermoid KB cell (KB-3-1) and the corresponding MDR1-transfected cell line (KB-G2). Western blot analysis and indirect immunofluorescence studies indicated that KB-G2, but not KB-3-1, exhibits the PGP ...
Park J H - - 1997
The trophozoite from of the protozoan parasite Giardia intestinalis is subjected to a changing osmotic environment in the small intestine of the host, and consequently effective osmoregulation and control of cell volume are essential to its survival. As a first step toward investigating the mechanism by which hypoosmotically-activated transport is ...
Putney L K - - 1997
PURPOSE: Previous studies in the authors' laboratory have shown that bovine and human trabecular meshwork (TM) cells possess a robust sodium-potassium-chloride (Na-K-Cl) cotransport system that functions in regulating intracellular volume and may play a central role in modulating outflow facility across the TM. Dexamethasone, which can induce ocular hypertension, has ...
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