Some factors affecting the phosphorescence/fluorescence ratio in tyrosine following excitation to higher-lying excited levels.
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Fluorescence↗
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Results for “Chloride Ion Level”
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A point mutation in a Drosophila GABA receptor confers insecticide resistance.
Vertebrates and invertebrates both have GABA (gamma-aminobutyric acid) as a major inhibitory neurotransmitter. GABAA receptors in vertebrates assemble as heteromultimers to form an integral chloride ion channel. These receptors are targets for drugs and pesticides and are also implicated in seizure-related diseases. Picrotoxinin (PTX) and cyclodiene insecticides are GABAA receptor antagonists which competitively displace each other from the same binding site. Insects and vertebrates showing resistance to cyclodienes also show cross-resistance to PTX. Previously, we used a field-isolated Drosophila mutant Rdl (Resistant to dieldrin) insensitive to PTX and cyclodienes to clone a putative GABA receptor. Here we report the functional expression and novel pharmacology of this GABA receptor and examine the functionality of a resistance-associated point mutation (alanine to serine) within the second membrane-spanning domain, the region thought to line the chloride ion channel pore. This substitution is found globally in Drosophila populations. This mutation not only identifies a single amino acid conferring high levels of resistance to the important GABA receptor antagonist PTX but also, by conferring resistance to cyclodienes, may account for over 60% of reported cases of insecticide resistance.
Alanine↗
Intracellular and extracellular chloride ions in the horizontal cells of the stingray retina.
Intracellular and extracellular concentrations of chloride ([Cl-]i, [Cl-]o) ions in the horizontal cells of the stingray retina were studied by means of ion-selective microelectrodes. The electrodes used were of the double-barreled type and Corning's #477315 resin was used as the exchanger. The average [Cl-]o and [Cl-]i in the L-type cells were 320 and 130 mM, respectively (n = 37), and the equilibrium potential (ECl) was calculated as -23.3 mV. In some cases, dark membrane potentials were more positive than the ECl. With white light stimulus, the membrane hyperpolarized to a more negative level than ECl. Based on the experiments described above, the hypothesis that the hyperpolarizing response of horizontal cells is due to the permeability change of the membrane to chloride ion was excluded in the stingray retina.
Animals↗
Sodium increases angiotensin II receptors in neuronal cultures from brains of normotensive and hypertensive rats.
Neuronal cultures from one-day-old brains of Wistar-Kyoto (WKY) and spontaneously hypertensive (SH) rats were used to determine the effect of sodium ions on angiotensin II (Ang II) receptors in order to understand the mechanism of action of sodium at the cellular level. Incubation with sodium chloride of neuronal cultures from WKY rats caused a rapid and dose-dependent increase in the specific binding of 125I-Ang II to its receptors. A 260% increase in the binding was observed with 150 mM NaCl. Neuronal cultures from SH rat brains showed a similar sodium-stimulated increase in Ang II binding; however this increase was 150% greater than that observed in neuronal cultures from WKY rat brain. Kinetic studies of the effects of sodium ions on both WKY and SH neuronal cultures showed an increase in the dissociation of 125I-Ang II from its receptors in the presence of sodium ions. In addition, Scatchard analysis revealed that the increase in binding caused by sodium was due to an increase in the number of Ang II receptors. These observations indicate that sodium ions increase the number of Ang II specific receptors in intact neuronal cells and that this stimulation was more pronounced in neuronal cells from SH rat brains compared with WKY controls.
Angiotensin II↗
Acute effects of sediments taken from an urban stream on physiological and biochemical parameters of the neotropical fish Prochilodus lineatus.
Juveniles of Prochilodus lineatus were exposed to sediments collected from one of five sites along an urban stream into which various types of contaminants are discharged. After 24 or 96 h fish were examined and the results compared with those from control groups (fish exposed only to water, for the same period). Plasma ion levels varied significantly and fish exposed to site 5 sediment showed a transient increase in both sodium and chloride concentrations. Plasma glucose was significantly higher in fish exposed to sediment from sites 2 and 5. The higher liver glutathione-S-transferase activity registered in fish exposed to sediment from sites 1, 4 and 5 suggests the presence of organic contaminants at these sites and the enhancement of liver catalase activity in fish exposed to sediment from sites 3 and 4 may be due to contaminant-mediated oxyradical production. The overall results revealed that sites 4 and 5 are more severely contaminated, probably due to organic contaminants from agricultural sources and municipal landfill.
Animals↗
Retention of Cr(III) by high-performance chelation ion chromatography interfaced to inductively-coupled plasma mass spectrometric detection with collision cell.
High-performance chelation ion chromatography (HPCIC) was employed to retain cationic Cr(III) on an anion-exchange column and hence allow the separation of the two most prevalent forms of chromium, Cr(II) and Cr(VI). A mobile phase of nitric acid was utilized at pH = 1.5; additionally, 2,6-pyridinedicarboxylic acid was used at a concentration of 6 mM. Additives with different structural characteristics were used in an effort to elucidate retention mechanisms. Inductively-coupled plasma mass spectrometry was used for chromium detection. A collision cell was utilized to reduce chloride-based polyatomic ions that may interfere with the detection of Cr(III), and a detection limit study yielded levels in the low part-per-billion range. The newly developed method was applied to the chromatographic analysis of samples of an incubation medium containing Cr(VI) incubated with cell nuclei.
Animals↗
PB1-F2, an influenza A virus-encoded proapoptotic mitochondrial protein, creates variably sized pores in planar lipid membranes.
A frameshifted region of the influenza A virus PB1 gene encodes a novel protein, termed PB1-F2, a mitochondrial protein that can induce cell death. Many proapoptotic proteins are believed to act at the mitochondrial outer membrane to form an apoptotic pore with lipids. We studied the interaction of isolated, synthetic PB1-F2 (sPB1-F2) peptide with planar phospholipid bilayer membranes. The presence of nanomolar concentrations of peptide in the bathing solution induced a transmembrane conductance that increased in a potential-dependent manner. Positive potential on the side of protein addition resulted in a severalfold increase in the rate of change of membrane conductance. sPB1-F2-treated membranes became permeable to monovalent cations, chloride, and to a lesser extent, divalent ions. Despite various experimental conditions, we did not detect the distinctive conductance levels typical of large, stable pores, protein channels, or even pores that are partially proteinaceous. Rather, membrane conductance induced by sPB1-F2 fluctuated and visited almost all conductance values. sPB1-F2 also dramatically decreased bilayer stability in an electric field, consistent with a decrease in the line tension of a lipidic pore. Since similar membrane-destabilizing profiles are seen with proapoptotic proteins (e.g., Bax) and the cytoplasmic helix of human immunodeficiency virus gp41, we suggest that the basis for sPB1-F2-induced cell death may be the permeabilization and destabilization of mitochondrial membranes, leading to macromolecular leakage and apoptosis.
Apoptosis↗
[Determination of chloride ion in additives of concrete by flame atomic absorption spectrometry].
Flame atomic absorption spectrometry due to its high sensitivity and selectivity has been widely used for the determination of micro levels of metal elements in various materials. But this method can not be used for the determination of Cl- directly. In this paper the determination of Cl- in additives of concrete by flame atomic absorption spectrometry was studied. Adding superfluous standard solution of Ag+ to the sample solution, the results were obtained by determining the remanent content of Ag+ having reacted with Cl- quantitatively. The acidity of the sample solution and the precision were studied. The standard rate of recovery obtained was in the range of 96%-104%. By the determination of actual samples it was proved that the method features simple sample preparation, fast determination, and little interference, especially for those samples which contain micro levels of Cl-. The procedure is as follows: weight 0.05-2 g of sample, dissolve it in water and adjust the acidity with nitric acid, add proper standard solution of Ag+, and after 2 h, measure the remanent Ag+ content by atomic absorption spectrometry. A GBC902 atomic absorption spectrometry was employed.
English Abstract↗
Effect of varying amounts of polysal and/or dextrose intravenous fluids on the blood levels of sodium, potassium, chloride and blood sugar.
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Anions↗
The quality of groundwater for certain chemicals in military fields in Ankara.
OBJECTIVE: The goal of this study was to determine the quality of groundwater for certain chemicals from all wells for the military units in Ankara (the capital city of Turkey) to evaluate special situations like a nuclear, biological, and chemical attack. METHOD: The quality of underground water has been evaluated chemically by examining 34 different water specimens. Various chemical parameters and heavy metals have been assessed in these samples by using an ion meter and atomic absorption spectrophotometer. RESULTS: Nitrate and chloride have been assessed at a higher rate with the levels exceeding maximum contaminant levels. Mercury, arsenic, aluminum, iron, conductivity, and salinity have also had levels exceeding maximum contaminant levels for each of them according to the levels set by the World Health Organization. CONCLUSION: This study has given us some powerful clues that underground water in Ankara is at a growing risk to be contaminated mainly with nitrate and chloride. Although more detailed investigations are necessary for a better evaluation, it is clear that preventive measures should be implemented or improved.
Military Hygiene↗
[Effect of calcium ions on adrenal glucocorticoid function].
In the experimental dogs and healthy humans it was shown that calcium ions promote activation of the adrenal glucocorticoids function, which duration is dependent on the day time. In patients the influence of calcium ions on the blood 11-hydroxycorticosteroid concentration is dependent on the initial steroid level and concentration of injected calcium chloride solution. The infusion of 1% calcium chloride solution exerted a stable effect. Possible mechanisms of the changes observed are discussed.
11-Hydroxycorticosteroids↗
A biochemical study of aminopeptidases in the palatal mucosa of the rat following tooth extractions.
Aminopeptidase activities were studied biochemically from the supernatants of the homogenates prepared from the normal and post extraction palatal mucosa of the rat. The determinations were carried out at 0.5, 1, 2, 4, 8 and 16 hours and 1, 2, 3, 5 and 7 days following extraction using N-L-aminoacyl-2-naphthylamines of arginine, glycine, leucine, proline and valine as the substrates. In addition, in the second part of the study the hydrolysis of N-L-aminoacyl-2-naphthylamines of alanine, histidine, isoleucine, lysine, phenylalanine, serine, threonine, tyrosine and valine was tested at 1, 3 and 5 days following extraction. The effect of chloride ions (0.2 M NaCl) on the hydrolysis of arginine and lysine derivatives was also tested. The specific activities of aminopeptidases obtained from the extraction-wound side were compared to those of the control side at each time interval. Tooth extraction caused a considerable reduction in the specific activities of aminopeptidases in the surrounding palatal mucosa immediately after extraction (at 0.5 hr.). The specific activities in the wound tissue remained generally below the control levels for 24 hours and reached their maximum within 5 days following extractions. The highest relative increase was obtained with N-L-valyl-2-naphthylamine. Arginine aminopeptidase was activated by chloride ions on an average 20 per cent more in the wound tissue than the control. This effect can be considered suggestive of the activation of aminopeptidase B in the post extraction palatal mucosa.
Aminopeptidases↗
Intrinsic (gas phase) thermodynamic stability of 2-adamantyl cation. Its bearing on the solvolysis rates of 2-adamantyl derivatives.
The standard enthalpy of formation of gaseous 2-adamantyl chloride(2-Ad-Cl) was determined by calorimetric techniques. The standard Gibbs energy change for the chloride anion exchange between 1-adamantyl (1-Ad+) and 2-adamantyl (2-Ad+) cations in the gas phase was obtained by Fourier transform ion cyclotron resonance spectroscopy (FT ICR). Theoretical calculations at the G2(MP2) level were performed on these and other relevant species. This and data from the literature provided three highly consistent independent estimates of the relative stabilities of 2-Ad+ and 1-Ad+. This difference in gas-phase stability was compared to the differential structural effects on the rates of solvolysis of the corresponding chlorides and tosylates, and it was shown that the thermodynamic stability of the secondary cation is the leading factor determining the solvolytic reactivity of the precursors in the absence of solvent effects. Thus, under these conditions, the previously established linear free energy correlation between carbenium ion stability and solvolytic reactivity of bridgehead derivatives applies also to secondary derivatives.
Journal Article↗
CFTR expression and chloride secretion in polarized immortal human bronchial epithelial cells.
A major limitation in the study of vectorial ion transport, secretion, and differentiated function in the human airway epithelium has been the lack of suitable cell culture systems. Progress in this direction has been made through the transformation of primary cultured epithelial cells. However, these transformants tend to lose differentiated properties with increasing serial passage, particularly following crisis. The successful establishment of a postcrisis SV40 large T-antigen transformed epithelial cell line derived from human bronchial epithelium is described. This cell line, 16HBE14o-, retains differentiated epithelial morphology and functions. Cell cultures show the presence of tight junctions and cilia, and monolayers generate transepithelial resistance, as measured in Ussing chambers, and retain beta-adrenergic stimulation of cAMP-dependent chloride ion transport, measured either by 36Cl- efflux or as short-circuit current in Ussing chambers. The cells also increase chloride transport in response to bradykinin or calcium ionophore. In addition, 16HBE14o- cells express levels of both the cystic fibrosis transmembrane conductance regulator (CFTR) mRNA and protein readily detectable by Northern and Western hybridization analysis, respectively. These cells provide a valuable resource for studying the modulation of CFTR and its role in regulation of chloride ion transport in human airway epithelium as well as other aspects of human airway cell biology.
Bronchi↗
Chloride channels activated by hyperpolarization in Aplysia neurones.
The outside-out configuration of the patch-clamp technique was used in order to characterize the elementary events underlying the previously described hyperpolarization-activated Cl current of Aplysia neurones. A few membrane patches bathed with K-free internal and external solutions showed channels characterized by long duration (up to several seconds) bursts of activity which were clearly activated by hyperpolarization. I-V curves of elementary current obtained for three different values of the Cl equilibrium potential show that these channels are selective for Cl ions. During the bursts, the current fluctuates between three levels: the resting (closed) level, a level of maximum conductance (10-15 pS) and a half-conductance level. This behaviour is similar to that of the Cl channels extracted from Torpedo electroplaques.
Animals↗
A novel flow-through microdialysis separation unit with integrated differential potentiometric detection for the determination of chloride in soil samples.
In this paper, a novel and miniaturised flow-through dialysis-based potentiometric detector is proposed for the determination of chloride in soil samples. The outstanding feature of the designed unit is the integration of analyte isolation from matrix constituents via membrane separation with differential potentiometric detection. Two identical tubular all-solid-state Ag/AgCl ion selective electrodes (ISEs) were assembled respectively at the inlet and outlet of the acceptor channel. Thus, as a consequence of the continuous forward flow of solutions through the microdialyser the outlet tube becomes the indicator electrode for the analyte diffusate while the nested tube at the entrance serves as reference electrode. The effect of physical and chemical parameters on the mass transfer efficiency is discussed in detail and compared with conventional configurations involving downstream detection. The membrane morphology for optimum dialysis performance is also thoroughly evaluated in terms of thickness, porosity and molecular weight cut-off. Higher dialysis efficiency and reduction of dilution factors up to a value of 5 were attained by halting the recipient stream temporarily. Under the optimised conditions, a dynamic working range of 5-5000 mg l(-1) chloride with a linear interval between 10 and 5000 mg l(-1) (for 1 min stopped-flow and 200 microl sample volume), a repeatability better than 3.0% and a 3 sigma(blank) detection limit of 1.2 mg l(-1) chloride were the analytical figures of merit of the devised configuration. The potentiometric dialysis sensor features extreme tolerance to high molecular weight interfering matrix compounds (> 1000 mg l(-1) humic acid), which makes it specially suited for the interference-free potentiometric determination of chloride in soils containing high levels of organic matter. The miniature size, low-reagent consumption and high analytical throughput (25-40 h(-1)) also warrant its applicability to in-field monitoring or screening schemes. The accuracy of the measurements was assessed using ion-chromatography as an external reference method. A mean t-test showed no statistical differences between both methodologies at the 95% confidence level.
Chlorides↗
Steady-state sodium absorption and chloride secretion of colon and coprodeum, and plasma levels of osmoregulatory hormones in hens in relation to sodium intake.
The plasma levels of four osmoregulatory hormones and their target ion-transport systems in the lower intestines of the domestic fowl were determined in order to elucidate their interrelationship and their setpoints in relation to NaCl intake. White Plymouth Rock hens were adapted to six intake levels of NaCl (0.20 +/- 0.02-24.7 +/- 1.9 mmoles Na+.kg bw-1.day-1) for 6 weeks. The Na+ absorption and the Cl- secretion of colon and coprodeum were characterized in vitro by the effects of hexoses, amino acids, amiloride, and theophylline on the short-circuit current (SCC) and electrical potential difference (PD). The NaCl-conserving system of the adult chicken is set at low intake levels of NaCl as the 80% range (quantized by non-linear, logistic regression analyses) of the change in the plasma [ALDO], the amiloride-inhibitable Na+ absorption of coprodeum and colon (delta SCC), occurred from 0.18 to 2.3, from 0.9 to 4.3, and from 1.2 to 7.3 mmoles Na+.kg bw-1.day-1, respectively. These results demonstrate that the amiloride-inhibitable Na+ absorption of coprodeum is more closely linked to plasma [ALDO] than that of colon. The aminoacid-Na+ coabsorption of colon increased over exactly the same range of Na+ intake as the colonic amiloride-inhibitable Na+ absorption decreased, whereas the hexose-Na+ coabsorption increased at higher levels of Na+ coabsorption increased at higher levels of Na+ intake, from 2 to 11 mmoles Na+.kg bw-1.day-1. Both these Na+ absorption types had reached their maximums at 24.7 mmoles Na+.kg bw-1.day-1, whereas the plasma [AVT] and plasma [PRL], although significantly increased, apparently had not; their 80% range of change occurred from 9.9 to 99 mmoles Na+.kg bw-1.day-1, and the main changes in plasma osmolality were predicted to occur from 5.4 to 107 mmoles Na+.kg bw-1.day-1. These results suggest that these colonic and hormonal variables conserve osmotically-free water and operate at high NaCl intake. The theophylline-induced colonic Cl- secretion did not change with NaCl intake, whereas the stimulation of SCC in coprodeum decreased with increasing NaCl intake: the main change occurred between 0 and 3.2 mmoles Na+.kg bw-1.day-1. Thus, all ion-transport capacity (although the nature of the Na+ transport changes). It is suggested that hormones defending the extracellular volume and composition are regulated close to zero input and output of both NaCl and water, regardless of whether they are NaCl conserving or free-water conserving.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Brain ion homeostasis in cerebral ischemia.
Brain function is severely disturbed in ischemia. Within seconds, consciousness and spontaneous activity is lost, whereas interstitial concentrations of major ions are kept near normal levels. After a few minutes, there is a dramatic increase of potassium and a lowering of sodium, chloride, and calcium concentrations. Similar ionic changes are observed during spreading depression, however, that is spontaneously reversible and may be elicited in the otherwise normally perfused brain. In focal ischemia, the two events occur simultaneously. The central core of very low flow displays the ischemic increase of interstitial potassium concentration, whereas the surrounding tissue exhibits repeated episodes of spreading depression. This may induce energy failure by stimulating metabolism in areas with depressed flow thereby causing cell damage outside the ischemic core.
Animals↗