PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Chloride Ion Level”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed1983

A simple method for the simultaneous measurement of sodium and chloride fluxes across transporting epithelia.

A simple technique for the separation of 22Na and 36Cl radioactivity in the same solution is described. Two samples were taken from a solution containing both 22Na and 36Cl. One sample was precipitated with AgNO3 and the other was untreated. Samples were assayed for radioactivity by liquid scintillation spectrophotometry. Precipitation with AgNO3 removed 100% of the 36Cl activity from solution while having no effect on the 22Na radioactivity. Thus precipitated samples contained only 22Na radioactivity. Subtraction of the radioactivity in the supernatants of precipitated samples (i.e. 22Na) from the total radioactivity of untreated samples (i.e. 22Na and 36Cl) yielded the level of 36Cl activity in these samples.

Animals↗
PubMed2005

Reduction of copper(II) by iron(II).

Laboratory and field investigations have clearly demonstrated the important role of reduced iron (Fe(II)) in reductive transformations of first-row transition metal species. However, interactions of Fe(II) and copper (Cu) are not clearly understood. This study examined the reduction of Cu(II) by Fe(II) in stirred-batch experiments at pH 5.2 and 5.5 as influenced by chloride (Cl-) concentration (0.002-0.1 M), initial metal concentration (0.1-9.1 mM), and reaction time (1-60 min) under anoxic conditions. Reduction of Cu(II) to Cu(I) by dissolved Fe(II) was rapid under all experimental conditions and the stability of the products explains the driving force for the redox reaction. Under conditions of low [Cl-] and high initial metal concentration, >40% of total Cu and Fe were removed from solution after 1 min, which accompanied formation of a brownish-red precipitate. X-ray diffraction (XRD) patterns of the precipitates revealed the presence of cuprite (Cu2O), a Cu(I) mineral, based on d-spacings located at 0.248, 0.215, 0.151, and 0.129 nm. Fourier transform infrared (FTIR) spectroscopy corroborated XRD data for the presence of Cu2O, with features located at 518, 625, and 698 cm(-1). Increasing [Cl-] stabilized the dissolved Cu(I) product against Cu2O precipitation and resulted in more Fe precipitated from solution (relative to Cu) that appears to be present as poorly crystalline lepidocrocite (gamma-FeOOH). This process may be important in anoxic soil environments, where dissolved Fe(II) levels can accumulate.

Chlorides↗
PubMed1998

The determination of benzalkonium chloride in eye-drops by difference spectrophotometry.

A direct, extraction-free spectrophotometric method was developed for the determination of benzalkonium chloride (BAC) in various eye-drops. The procedure is based on ion-pair formation between BAC and 2',4',5',7'-tetrabromofluorescein (eosin-Y) which decreases the absorbance and induces a bathochromic shift of the maximum in the eosin-Y spectrum. The effects of pH, excess of reagent and ionic strength on the ion-pair formation have been studied in detail. At pH 4.40 and 9.62, the working curve is linear in the 1.98 x 10(-6) to 2.40 x 10(-5) M (0.7-8.5 microg cm[-3]) concentration range; however, the sensitivity drops to about one third in the basic solution. At pH 4.40, the analytical signal is stable for more than 60 min, while at pH 9.62 the signal changes in time and reaches the maximum value 3 min after mixing the reagent and the sample. When the active substance is beta-5-isopropyl-2'deoxyuridine and the sample contains typical additives, the reproducibility of the analytical signal at pH 4.40 is R.S.D. = 2.36% (n = 81). In the case of such samples, the linearity of the method is somewhat dependent on the composition, but generally acceptable at the 50-150% concentration levels. Eye-drops containing tobramycin, an aminoglycoside-type antibiotic, as the active substance were analyzed at pH 9.62. This was necessary to avoid strong interference from the analyte in acidic solution. In this case the linearity of the method is limited to a narrower concentration range; however, the recovery is still acceptable at the 100% level.

Benzalkonium Compounds↗
PubMed1993

The effect of feeding various levels of Bifidobacterium globosum A on the performance, gastrointestinal measurements, and immunity of weanling pigs and on the performance and carcass measurements of growing-finishing pigs.

Four trials using 312 weanling pigs (average initial weight, 7.2 kg) were conducted to examine the effect of Bifidobacterium globosum A (BGA) on the growth performance, scour scores, humoral and cell-mediated immune response, and pH and chloride ion concentration (CIC) of feces and gastrointestinal tract contents of pigs. Dietary treatments were 0, 5.0 x 10(4), 6.7 x 10(6), and 7.5 x 10(8) colony forming units (cfu) of BGA/d in Trial 1 and 0, 6.0 x 10(4), 5.0 x 10(5), and 5.0 x 10(6) cfu/d in Trials 2 through 4. Pigs fed the low or medium levels of supplemental BGA had a greater ADG (P < .05) than control pigs throughout Trial 1, whereas ADG was quadratically increased (P < .05) for the low or medium levels only during wk 3 to 5 for the pooled data for Trials 2, 3, and 4. The primary effect of dietary BGA additions on ADFI was a quadratic increase during wk 3 to 5 for Trial 1 (P < .05) and for the pooled data of Trials 2 through 4 (P < .10). Gain:feed ratios were generally unaffected by addition of BGA. Both ADFI and ADG tended to be decreased (P < .10) at the highest level of BGA in all trials. Scouring was not severe in any of the trials and was not consistently affected by feeding BGA. The pH and CIC of gastrointestinal contents or feces were not influenced by the feeding of BGA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

A streamlined method for the isolation and quantitation of nanomole levels of exported polyamines in cell culture media.

A number of years ago, our laboratory published a method for the isolation of small amounts of polyamines from cell culture media using the ion-exchange resin Bio-Rex 70. We have used this technique extensively to study the export of putrescine and cadaverine from cultured mammalian cells. Unfortunately, this method was highly inefficient in isolating the polyamines spermidine and spermine and was incapable of recovering the acetylated polyamine N(1)-acetylspermidine. In response to these shortcomings, we modified our previous protocol to quantitatively isolate the polyamines N(1)-acetylspermidine, putrescine, cadaverine, N(1)-acetylspermine, spermidine, and spermine. The new method, which is much faster to perform and more efficient than the one previously described, employs the use of disposable minicolumns and a single resin washing step using a weak solution of sodium carbonate at pH 9.3. This new protocol also eliminates the column elution step in favor of directly derivatizing the polyamines with dansyl chloride on the ion-exchange resin. High-performance liquid chromatography analysis of the dansylated polyamines isolated by this procedure showed that 75% of N(1)-acetylspermidine and nearly 100% of the other polyamines present in nanomolar levels were recovered from small amounts of cell culture medium. This new protocol is a valuable new tool for the study of the intracellular/extracellular dynamics of polyamine pools in cultured cells. [A detailed laboratory protocol for this procedure (containing all of the information in this paper but in a condensed form) can be requested by e-mailing the authors.]

Biogenic Polyamines↗
PubMed1985

Direct measurement of pH in the rat lens by ion-sensitive microelectrodes.

The resting pH of the rat lens was determined using H+-sensitive liquid membrane microelectrodes and found to be 6.89 when measured in a perifusing solution of pH 7.20. The pH of the rat vitreous humour was also measured and was found to be 7.25. Attempts were made to perturb the lens pH by varying the pH of the perifusate. In the presence of alkaline solutions, the lens was able to maintain its resting pH and membrane potential but, upon perfusion with a more acidic solution, the lenticular pH equilibrated with the pH of the bathing solution and the potential depolarized. The internal pH could be manipulated independently of the external pH by perfusing the lens with Ringer solution containing 20 mM ammonium chloride. The ammonium chloride induced a rapid alkalinization and the return to control solution caused a fall in pH to below the normal resting level. The biphasic pH response to ammonium chloride was accompanied by changes in lens transparency and membrane potential.

Ammonium Chloride↗
PubMed1991

Intracellular chloride activity in cultured mesangial cells.

Glomerular mesangial cells require Cl ions for the development of a variety of metabolic and functional properties. In the present study the electrochemical distribution for Cl- was examined in cultured rat mesangial cells with Cl(-)-sensitive intracellular microelectrodes. It was determined that the intracellular Cl activity exceeded the levels predicted for a passively distributed ion. This was further substantiated by exposing mesangial cells to 10(-5) M bumetanide which drove intracellular Cl to a value close to electrochemical equilibrium. We conclude that Cl accumulates in mesangial cells, against its electrochemical gradient, through a transport pathway that is highly sensitive to bumetanide.

Animals↗
PubMed2000

A laboratory study evaluating the release of hydroxyl ions from various calcium hydroxide products in narrow root canal-like tubes.

AIM: The aim of the present study was to describe pH changes in a variety of buffering solutions within a narrow test tube containing either a gutta-percha point with incorporate calcium hydroxide, a commercial calcium hydroxide paste (Calcicur) or a freshly mixed paste of calcium hydroxide in distilled water. METHODOLOGY: The test material was placed centrally in a test tube of 2 mm inner diameter. Saline (1%) was placed at one end, whilst the buffering solutions were introduced at the other. The pH of the buffering solutions was monitored using electrodes placed at each end of the test tube. RESULTS: It was found that the pH 4.01 buffer strongly resisted pH changes at levels below 6.0, whilst saliva and bovine serum was buffered less and more evenly in the whole range up to pH 11.5. The calcium hydroxide containing gutta-percha points caused the pH to increase quickly in the sodium chloride solution to levels above 11.5. However, in bovine serum, in saliva and in the pH 4.01 buffer the pH remained below 8.5, 8.0 and 6.0, respectively, 1 mm from the point. In contrast, the release of hydroxyl ions from the two calcium hydroxide pastes brought pH above pH 11.5 irrespective of the buffering of the solutions 5 mm from the paste. CONCLUSION: It is concluded that Calcicur and the calcium hydroxide-water mixture contained substantially more available calcium hydroxide than did the calcium hydroxide containing gutta-percha points, with the result that the release of hydroxyl ions from the points was limited in comparison to that from the pastes.

Animals↗
PubMed2000

Model studies of the precipitation of silica in the presence of aluminium; implications for biology and industry.

The unique chemical affinity between the oxides of silicon and aluminium has been cited as a potential route for the amelioration of the detrimental effects of aluminium in the environment and in biological systems. A greater understanding of silicon-aluminium interactions may assist in this endeavour and also provide a means of overcoming silica fouling problems encountered by industry which are exacerbated by the presence of aluminium. It is also conceivable that this increased knowledge may demonstrate a positive use for aluminium in the processing of the silicon dioxide phase. In this study we report the effect of aluminium ions, derived from aluminium chloride, on silicic acid species obtained from potassium catecholato complexes of silicon at circumneutral pH at the molar ratios 1000Si:Al, 100Si:Al and 50Si:Al. Silica and low levels of aluminium-rich silica materials were formed with Si:Al ratios of about 3.5:1 comparable with the element ratios detected in senile plaques and aluminium-rich scale. A kinetic study showed that aluminium in the reaction medium slowed down the rate of formation of one of the silica species formed early in the condensation process, e.g. trimers, but increased the rate at which silicic acid was removed from sub 1 nm diameter particles. The materials precipitated in the presence of aluminium were composed of smaller particles and aggregates with smaller pores (Si100:Al and Si50:Al systems) or larger pores (Si1000:Al) compared to the control. The nature of the interactions responsible for these differences is discussed. The effects described here demonstrate the ability of silica and aluminium to interact under conditions such as those found in biological systems. That silica reacts with aluminium in the presence of catechol supports the protective role assigned to silicon.

Aluminum↗
PubMed1995

Li+ stimulates ATP-regulated dopamine uptake in PC12 cells.

Increased levels of dopamine have been associated with schizophrenia and mania; conversely, decreased levels of dopamine are associated with depression. Since the main mechanism for the termination of dopamine's pharmacological action is by re-uptake into the presynaptic cell, the speed of dopamine transport dramatically influences the concentration of dopamine present in the synaptic cleft, which in turn could determine brain disorders. Our preliminary studies have found that ATP can stimulate dopamine transport in rat synaptosomal preparation. We have also observed this ATP-regulated moiety of the dopamine uptake system when tested in PC12 cells. The large magnitude of ATP stimulation suggests that this dopamine uptake pathway may be important in the etiology and treatment of brain disorders. In order to test the relevance of ATP-stimulated dopamine uptake, we tested the effect of lithium salts on this system. Lithium chloride, one of the first drugs used in the treatment of mania, has become one of the most important agents utilized for the treatment of manic-depression and many schizoeffective disorders. Unfortunately, despite all efforts that have been made to explain lithium's mode of action, a clear cut biochemical mechanism has not been defined. We have found that lithium chloride, at therapeutic levels, is able to stimulate the ATP-regulated component of the dopamine uptake system by 49%. The further enhancement of dopamine re-uptake by lithium ions is consistent with its therapeutic effect. It is suggested that any substance that facilitates dopamine re-uptake could be of great importance in defining a useful treatment for mania and schizophrenia, as well as depression.

Adenosine Triphosphate↗
PubMed1997

Size exclusion HPLC method for the determination of acidic fibroblast growth factor in viscous formulations.

A size exclusion HPLC method has been developed to determine the protein concentration of pharmaceutical formulations of recombinant acidic fibroblast growth factor (aFGF). These topical aFGF formulations not only contain low levels of protein mass (50 micrograms ml-1), but also include buffer ions, polysaccharide polyanions to conformationally stabilize aFGF and 1% hydroxyethylcellulose to increase the solution's viscosity. A cesium chloride mobile phase is utilized during SEC-HPLC to dissociate aFGF from the pharmaceutical excipients and to minimize nonspecific interaction of the protein with the column matrix. The protein content of a viscous aFGF formulation is determined by comparison of aFGF peak areas to standards of known concentration. Fluorescence spectroscopy was utilized to directly demonstrate that the protein remains in its native conformation during sample preparation and analysis.

Chemistry, Pharmaceutical↗
PubMed2006

Structure of testis ACE glycosylation mutants and evidence for conserved domain movement.

Human angiotensin-converting enzyme is an important drug target for which little structural information has been available until recent years. The slow progress in obtaining a crystal structure was due to the problem of surface glycosylation, a difficulty that has thus far been overcome by the use of a glucosidase-1 inhibitor in the tissue culture medium. However, the prohibitive cost of these inhibitors and incomplete glucosidase inhibition makes alternative routes to minimizing the N-glycan heterogeneity desirable. Here, glycosylation in the testis isoform (tACE) has been reduced by Asn-Gln point mutations at N-glycosylation sites, and the crystal structures of mutants having two and four intact sites have been solved to 2.0 A and 2.8 A, respectively. Both mutants show close structural identity with the wild-type. A hinge mechanism is proposed for substrate entry into the active cleft, based on homology to human ACE2 at the levels of sequence and flexibility. This is supported by normal-mode analysis that reveals intrinsic flexibility about the active site of tACE. Subdomain II, containing bound chloride and zinc ions, is found to have greater stability than subdomain I in the structures of three ACE homologues. Crystallizable glycosylation mutants open up new possibilities for cocrystallization studies to aid the design of novel ACE inhibitors.

Amino Acid Sequence↗
PubMed2005

Modeling protic to dipolar aprotic solvent rate acceleration and leaving group effects in S(N)2 reactions: A theoretical study of the reaction of acetate ion with ethyl halides in aqueous and dimethyl sulfoxide solutions.

The S(N)2 reactions between acetate ions and ethyl chloride, ethyl bromide, and ethyl iodide in aqueous and dimethyl sulfoxide (DMSO) solutions were theoretically investigated at an ab initio second-order Møller-Plesset perturbation level of theory for geometry optimizations and at a fourth-order Møller-Plesset perturbation level for energy calculations. The solvent effect was included by the polarizable continuum model using the Pliego and Riveros parametrization for DMSO and the Luque et al. scale factor for the water solution. The calculated DeltaG() values of 24.9, 20.0, and 18.5 kcal mol(-1) in a DMSO solution for ethyl chloride, ethyl bromide, and ethyl iodide are in good agreement with the estimated experimental values of 22.3, 20.0, and 16.6 kcal mol(-1), respectively. In an aqueous solution, the theoretical Delta G++ barriers of 26.9, 23.1, and 22.1 kcal mol(-1) are also in good agreement with the estimated experimental values of 26.1, 25.2, and 24.7 kcal mol(-1), respectively. The present ab initio calculations are reliable to predict the absolute and relative reactivities of ethyl halides in a DMSO solution, but in the aqueous phase, the results are less accurate. The protic to dipolar aprotic solvent rate acceleration is theoretically predicted, although this effect is underestimated. We suggest that further improvement of the present results could be obtained by including liquid-phase optimization in both solvents and treating specific solvation by water molecules for the reaction in the aqueous phase.

Journal Article↗
PubMed2006

Role of dietary sodium in osteoporosis.

Sodium, in the form of sodium chloride, elevates urinary calcium excretion and, at prevailing calcium intakes, evokes compensatory responses that may lead to increased bone remodeling and bone loss. The calciuria is partly due to salt-induced volume expansion, with an increase in GFR, and partly to competition between sodium and calcium ions in the renal tubule. Potassium intakes in the range of current recommendations actually reduce or prevent sodium chloride-induced calciuria. At calcium intakes at or above currently recommended levels, there appear to be no deleterious effects of prevailing salt intakes on bone or the calcium economy, mainly because adaptive increases in calcium absorption offset the increased urinary loss. Such compensation is likely to be incomplete at low calcium intakes. Limited evidence suggests equivalent bone-sparing effects of either salt restriction or augmented calcium intakes. Given the relative difficulty of the former, and the ancillary benefits of the latter, it would seem that the optimal strategy to protect the skeleton is to ensure adequate calcium and potassium intakes.

Animals↗
PubMed1995

Anxiolytic effect of progesterone is mediated by the neurosteroid allopregnanolone at brain GABAA receptors.

Previous studies from this laboratory have shown that progesterone (PROG) treatment in ovariectomized rats produces an anti-anxiety response similar to that observed after the administration of prototypical anxiolytic benzodiazepine (BDZ) compounds. The PROG-induced anxiolytic response was highly correlated with an increased level of 3 alpha-hydroxy-5 alpha-pregnan-20-one (allopregnanolone) in the blood and brain, and was also associated with a facilitation of GABA-stimulated chloride ion (Cl-) influx in cortical synaptoneurosomes. This correlative evidence suggested that the anxiolytic effect of PROG was a result of its in vivo reduction to the neuroactive steroid, allopregnanolone. In this report, a series of studies was conducted to determine the mechanism(s) by which PROG alters behavior in animal models of anxiety. In the first experiment, ovariectomized rats were injected with PROG (1 mg/0.2 ml, SC) 4 h prior to a test in the elevated plus-maze. Some animals also received an injection of picrotoxin (0.75 mg/kg, IP), a GABAA receptor-gated Cl- channel antagonist, whereas other animals were pretreated with RU 38486 (5 mg/0.2 ml, SC), a progestin receptor antagonist. PROG elicited anxiolytic behavior in the plus-maze, an effect that was blocked by picrotoxin administration. Pretreatment with RU 38486 was not effective in altering PROG-induced anxiolytic behavior in the plus-maze. In a second experiment, the effect of PROG on behavior in the plus-maze was determined in the presence of N,N-diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane-17 beta-carboxamide (4-MA; 10 mg/0.2 ml, SC), a 5 alpha-reductase inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1982

Fungistatic capacity of sera from guinea pigs injected with various iron solutions: differences between Trichophyton mentagrophytes and Rhizopus oryzae.

The fungistatic capacity and serum ion levels (SI) of guinea pigs given subcutaneous injections of various iron solutions were examined. The administration of 2.0 ml of 0.1 M ferric ammonium sulfate, ferric sulfate, or ferric chloride subcutaneously had no significant effect on the SI 3 h after administration, whereas ferric ammonium citrate, ferric citrate, or ferrous sulfate elevated the SI to 50 to 140 times that necessary to saturate the unbound transferrin in normal sera. The sera from 11 of 15 guinea pigs with an elevated SI remained fungistatic for Trichophyton mentagrophytes, whereas 3 of 15 guinea pigs with an elevated SI remained fungistatic for Rhizopus oryzae. The sera from normal guinea pigs were consistently fungistatic for Rhizopus oryzae. The sera from normal guinea pigs were consistently fungistatic for both T. mentagrophytes and R. oryzae. These data suggest that subcutaneous administration of certain iron compounds can significantly elevate the SI without completely abolishing the fungistatic capacity of the serum.

Animals↗
PubMed2001

Electrothermal vaporization on a tungsten filament for the determination of arsenic in chloride solutions by low-pressure helium ICP-MS.

A combined method of electrothermal vaporization and low-pressure helium ICP-MS was developed for the determination of traces of arsenic in chloride solutions, because serious spectral interference occurred in conventional argon ICP-MS. On a tungsten filament was placed 5 microl of a sample and heated electrothermally to remove the solvent. The resulting residue on the filament was covered with a vaporization chamber, and after reducing the pressure to ca. 5 Torr, it was rapidly heated by discharging a high-capacity condenser (0.22 F). The vapor of arsenic was transferred to a helium plasma with a stream of carrier gas for the determination. The background was not observed at m/z of 75, which allowed the determination of arsenic at ng/ml levels in chloride solutions. Sodium chloride significantly enhanced the intensity of the arsenic signal, whereas other chlorides, including KCl, MgCl2, CaCl2 and NH4Cl, suppressed the analytical signals. This enhancement due to sodium ions seems to be a peculiar phenomenon to the helium ICP. The proposed method can be applied to direct determinations of as low as 0.9 ng/ml of arsenic in seawater.

Journal Article↗