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PubMed2006

Impact of chloride balance in acidosis control: the Stewart approach in hemodialysis critically ill patients.

BACKGROUND: Metabolic acidosis is highly prevalent in critically ill patients with acute renal failure. Little is known about the mechanisms by which renal replacement therapy intervenes in such cases. The objective of this study is to analyze the role of hemodialysis in acidosis correction in intensive care unit patients, with an emphasis on chloride levels in plasma and dialysate. METHODS: We studied 19 intermittent hemodialysis procedures in 17 acidotic patients. The patients were grouped by procedure type (conventional or sustained low-efficiency dialysis) and by predialysis plasma chloride level (higher or lower than the dialysate chloride concentration). Immediately before and after each procedure, blood samples were collected for biochemical analysis. The Stewart method was used to calculate the strong ion difference and strong ion gap. RESULTS: The patients presented acidosis related to hyperchloremia, hyperphosphatemia, and high unmeasured anions. Hypoalbuminemia had an alkalinizing effect. Hemodialysis corrected acidosis mainly by reducing phosphate and unmeasured anions. In the group as a whole, chloride levels did not change after dialysis. However, when analyzed according to predialysis plasma chloride, the high-chloride group presented a reduction in plasma chloride, resulting in better base excess improvement (Delta standard base excess) than in the low-chloride group. Among the determinants of acid-base status, the only factors correlating with Delta SBE were Delta strong ion gap and Delta chloride. CONCLUSION: The serum chloride/dialysate chloride relationship during hemodialysis has an important impact on acidosis control.

Acidosis↗
PubMed1979

Ionic gradients within mantle-collar epithelial cells of the land snail Otala lactea.

Aestivating Otala lactea have been shown to reduce the rate of evaporative water loss from the cells of the mantle-collar epithelium to a level comparable to that of an insect. X-ray microanalyses of ultrathin frozen sections from aestivating and non-aestivating snails have shown gradients of chloride and potassium ions in the apical microvillus region of the regulating mantle collar epithelium. The greatest difference in osmotic concentration occurs in the apical 2 micron of the cell. There appears to be a barrier at that level that prevents water being mobilised from the underlying tissues. Methods of presenting data generated by X-ray microanalysis are also discussed.

Animals↗
PubMed1994

Long-term uncoupling of chloride secretion from intracellular calcium levels by Ins(3,4,5,6)P4.

Osmoregulation, inhibitory neurotransmission and pH balance depend on chloride ion (Cl-) flux. In intestinal epithelial cells, apical Cl- channels control salt and fluid secretion and are, in turn, regulated by agonists acting through cyclic nucleotides and internal calcium ion concentration ([Ca2+]i). Recently, we found that muscarinic pretreatment prevents [Ca2+]i increases from eliciting Cl- secretion in T84 colonic epithelial cells. By studying concomitant inositol phosphate metabolism, we have now identified D-myo-inositol 3,4,5,6-tetrakisphosphate (Ins(3,4,5,6)P4), as the inositol phosphate most likely to mediate this uncoupling. A novel, membrane-permeant ester prepared by total synthesis delivers Ins(3,4,5,6)P4 intracellularly and confirms that this emerging messenger does inhibit Cl- flux resulting from thapsigargin- or histamine-induced [Ca2+]i elevations.

Atropine↗
PubMed1975

Gas-liquid chromatographic determination of vinyl chloride in alcoholic beverages, vegetable oils, and vinegars.

Vinyl chloride in foods is determined by gas-liquid chromatography either by direct injection of vinegars and alcoholic beverages or by headspace analysis of vegetable oils. The lower limit of detection is 10-15 ng/ml for direct injection and 1-10 ppb for headspace analysis. Confirmation by gas chromatography-mass spectrometry, single ion monitoring at m/c 62, is possible at 50 ppb for either method. The levels of vinyl chloride bottles were 0.0-1.6 mu-g/ml for alcoholic beverages, 0.0-8.4 mu-g/ml for vinegars, and 0.3-3.3 ppm for peanut oil.

Acetates↗
PubMed1993

[An attempt to investigate the effect of magnesium ion supplements on changes in levels of nitrates and nitrites in selected pickled vegetables].

The aim of this study was to examine the effect of magnesium ions on some changes in the nitrate reductase activity in the white headed cabbage as well as a practical application of the results obtained in vegetable souring. As experimental material were used: white and red headed cabbage, red beets and the same vegetable in the soured form. Vegetable souring was performed using a traditional method as well as a modified one, considering a supplement of magnesium chloride at various levels during the process of souring. The activity of nitrate reductase in the white headed cabbage was determined by the Jaworski method. In raw and soured vegetables the level of nitrates was determined by brucine method and that of nitrites by the Griess colorimetric method. A supplement of magnesium ions to the incubation mixture containing raw white cabbage resulted in an increased activity of the studied enzyme by 17.0-34.8% and was significant in all magnesium ions concentrations used. The introduction of adequate amounts of magnesium chloride to soured vegetable production resulted also in a significant decrease in the nitrate and nitrite levels. An organoleptic evaluation of soured vegetables made by a traditional method and by using a supplement high quality, although the smell of white headed cabbage and "beet acid" has slightly however, significantly deteriorated.

Brassica↗
PubMed1988

Chronic ethanol administration alters gamma-aminobutyric acid, pentobarbital and ethanol-mediated 36Cl- uptake in cerebral cortical synaptoneurosomes.

The effect of chronic ethanol exposure on the function of the gamma-aminobutyric acid (GABA) receptor-coupled chloride ion channel was studied in synaptoneurosomes from rat cerebral cortex. Ethanol was administered to rats by inhalation resulting in high blood ethanol levels which have previously been shown to produce tolerance and dependence. After 14 days of ethanol exposure, the stimulation (apparent Vmax) of 36Cl- uptake by the GABA agonist muscimol was decreased by approximately 26%. Similarly, stimulation of 36Cl- uptake by the barbiturate pentobarbital was also reduced to the same extent and there was an increase in the apparent EC50 concentration. Direct stimulation of 36Cl- uptake by ethanol was unchanged after chronic ethanol exposure when measured in the same membrane preparations in which a decrease in muscimol and pentobarbital-stimulated 36Cl- uptake were observed. However, ethanol's ability to potentiate muscimol-stimulated 36Cl- uptake was abolished completely in synaptoneurosomes from ethanol-treated rats. The decrease in GABA receptor-coupled chloride ion channel function observed after chronic ethanol administration was observed only in animals where the mean blood ethanol concentration was greater than or equal to 150 mg%. These blood levels have previously been shown to be associated with ethanol withdrawal after ethanol discontinuation in this rat strain. Four days after ethanol administration, after all signs of ethanol withdrawal had subsided, the decrease in muscimol and pentobarbital-stimulated 36Cl- uptake was reversed. These data suggest that subsensitivity of the GABA receptor-coupled chloride ion channel after chronic ethanol administration may contribute to ethanol tolerance and the ethanol withdrawal syndrome.

Administration, Inhalation↗
PubMed2003

Unexplained metabolic acidosis in critically ill patients: the role of pyroglutamic acid.

OBJECTIVE: To determine the role of pyroglutamic acid (PGA) in the pathogenesis of unexplained metabolic acidosis in critically ill patients. DESIGN AND SETTING: Case series in the medical ICU of an urban hospital. PATIENTS: 23 patients admitted to the medical ICU with acidemia (pH <7.35 or HC0(3) < or = 16 mEq/l) not explained by the presence of ketoacidosis, lactic acidosis, renal failure or ingestion of drugs or toxins and who had an increase in the strong ion gap (SIG) greater than 5. MEASUREMENTS AND RESULTS: Plasma levels of sodium, potassium, chloride, bicarbonate, calcium (ionized), magnesium, lactate, phosphate, albumin, blood urea nitrogen, and creatinine were measured. Arterial blood gases and urine dipstick for ketones were also analyzed. Plasma was assayed for PGA using gas chromatography. The patient's history and Kardex were reviewed for evidence of acetaminophen administration. The plasma PGA level was found to be very low in all patients studied. The correlation between SIG and PGA (r) was -0.01 (95% CI: -0.42 to 0.40). PGA therefore did not account for the observed increase in the SIG. There appeared to be no obvious influence of acetaminophen intake on levels of PGA in the plasma. CONCLUSIONS: We were unable to confirm the importance of PGA as a cause of unexplained metabolic acidosis and increased SIG in our critically ill patients.

Acid-Base Equilibrium↗
PubMed1977

Alterations in the dog renal tubular epithelium during normothermic ischemia.

Dog kidneys were subjected to one, two, or three hours' normothermic ischemia in situ and were then excised for biochemical and histological evaluation. The uptake of para-aminohippurate (PAH) by cortical slices progressively decreased with prolongation of the ischemia, but active transport was never abolished. Glycine uptake and oxygen consumption were only reduced to a modest extent by the ischemia. The intracellular ion levels were drastically altered, with loss of potassium and gain of sodium and chloride, and considerable increases in tissue water were observed. Acid phosphatase was liberated by the whole organ into the venous blood and by the incubated slices into the incubation medium, but both biochemical and histochemical techniques showed that the total quantity of the enzyme in the cells was hardly changed. The histochemical reaction product was localized exclusively in the lysosomes. Morphological damage was slight after one or two hours' ischemia, but more pronounced after three hours, when some cells were seen to be detached from the basement membrane. These relatively minor changes seem insufficient to predict the ultimate fate of the organ after ischemia.

Acid Phosphatase↗
PubMed2005

Development of a highly sensitive monoclonal antibody based ELISA for detection of benzo[a]pyrene in potable water.

In Europe, a limit value of 10 ng L(-1) was set by the European Commission for benzo[a]pyrene (B[a]P) in water intended for human consumption (Council Directive 98/83/EC) and, therefore, sensitive and reliable methods are needed to evaluate its presence. We report here on the development of a highly sensitive indirect competitive ELISA for the detection of B[a]P in potable water. Fourteen monoclonal antibodies were generated in mice using novel B[a]P derivatives. The immunoassay with the least interference and the best sensitivity was optimized and characterized. As co-solvent, ten percent methanol (v/v) was determined as the optimum concentration for B[a]P solubilization for use with the developed ELISA. With the purified antibody (clone 22F12) the average IC50 for B[a]P and corresponding detection limit at a signal:noise (S/N) ratio of 3 was 65 ng L(-1) and 24 ng L(-1), respectively. From the 16 EPA-designated PAHs, only chrysene, indeno[1,2,3-cd]pyrene, and benzo[b]fluoranthene showed a cross-reactivity (CR) higher than 20%. No CR was observed for two- and three-ringed aromatics as well as dibenz[ah]anthracene and benzo[ghi]perylene. The effect of pH value (range 6.5-9.5), ionic strength (specific electric conductivity 1 microS cm(-1)-2.5 mS cm(-1)), and inorganic ions (sodium, copper, iron, aluminium, manganese, chloride, sulfate, nitrate, and nitrite at maximum permissible levels according to the Council Directive) on both signal and sensitivity of the ELISA was studied. No significant influence of these parameters on the ELISA competition curve was found. We suggest that the optimized ELISA can be used to monitor potable water samples without previous extraction from the samples. The assay should facilitate the cleanup of B[a]P contaminated sites where B[a]P levels fall close to the limit value of the new drinking water directive.

Animals↗
PubMed2005

Atypical slow waves generated in gastric corpus provide dominant pacemaker activity in guinea pig stomach.

When intracellular recordings were made from the circular layer of the intact muscular wall of the isolated guinea pig gastric corpus, an ongoing regular high frequency discharge of slow waves was detected even though this region lacked myenteric interstitial cells. When slow waves were recorded from preparations consisting of both the antrum and the corpus, slow waves of identical frequency, but with different shapes, were generated in the two regions. Corporal slow waves could be distinguished from antral slow waves by their time courses and amplitudes. Corporal slow waves, like antral slow waves, were abolished by buffering the internal concentration of calcium ions, [Ca2+]i, to low levels, or by caffeine, 2-aminoethoxydiphenyl borate or the chloride channel blocker DIDS. Corporal preparations demonstrated an ongoing discharge of unitary potentials, as has been found in all other tissues containing interstitial cells. The experiments show that the corpus provides the dominant pacemaker activity which entrains activity in other regions of the stomach and it is suggested that this activity is generated by corporal intramuscular interstitial cells.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1991

Release of benzalkonium chloride from a heparin-bonded umbilical catheter with resultant factitious hypernatremia and hyperkalemia.

Elevated serum sodium and potassium levels were recently observed when sampled through a heparin-bonded umbilical catheter and measured with certain ion-selective electrodes. The cationic surfactant, benzalkonium chloride (BZC), is known to falsely elevate those cations in serum. Inasmuch as most heparin-bonded umbilical catheters use BZC during the bonding process, an in vitro study was performed to estimate the quantity of BZC released and the duration of sodium and potassium elevations during pooled sera infusion. Three heparin-bonded umbilical catheters and 3 silastic umbilical catheters were first flushed with 0.3 mL of normal saline and then perfused with pooled sera (sodium, 142 mEq/L; potassium, 4.6 mEq/L) at 2.5 microL/h. Effluent samples were collected from 0 to 8 hours and analyzed by ion-selective electrodes. Elevated serum sodium concentrations from 160 to greater than or equal to 250 mEq/L and potassium concentrations from 6.0 to greater than or equal to 9.6 mEq/L were observed. The BZC concentration in the catheter effluent was measured by mass spectrometry, with peak values of 10 micrograms/mL detected by this method. When varying concentrations of BZC (1 to 100 micrograms/mL) were added directly to pooled serum, a dose-dependent increase in serum sodium was observed. These data demonstrate that BZC released from heparin-bonded umbilical catheters elevates serum electrolyte values measured with some ion-selective electrodes. The observed increase in sodium and potassium concentrations may lead to clinical errors in management. Benzalkonium chloride is associated with myriad of linical symptomatology. Whether this amount of BZC is toxic in the small premature neonate is presently unknown.

Benzalkonium Compounds↗
PubMed2003

Real time air monitoring of hydrogen chloride and chlorine gas during a chemical fire.

On 9 August 2000 a fire started at a facility that manufactures pool chemicals in Guelph, Ontario. A mobile trace atmospheric gas analyzer (TAGA) unit was summoned to provide on-site air monitoring operated by the Ontario Ministry of the Environment (OMOE). The responsibility of the TAGA unit was to monitor in real time the airborne contaminants released through the combustion of pool chemicals. This was accomplished by using an atmospheric pressure chemical ionization (APCI) source with the newest TAGA (model IIe): a triple quadrupole mass spectrometer which allows for the direct sampling and real time analysis of air for a wide range of toxics at low parts-per-billion (ppb) levels. The ionization mechanism under negative APCI conditions is dominated by charge transfer reactions, yielding parent ions which are selected in Q1, dissociated in Q2 and the resultant daughter ions are identified in Q3. By monitoring specific parent/daughter (P/D) ion pairs, the TAGA IIe was able to simultaneously measure, in real time, levels of hydrogen chloride (HCl) and chlorine (Cl2) present in the air. The response of the TAGA IIe was characterized by multi-point calibration curves which were linear up to 250 microg/m3 for HCl and up to 600 microg/m3 for Cl2. The average detection limit (DL) for this application was 0.50 microg/m3 for both HCl and Cl2. On-site measurements of HCl and Cl2 were made at several locations upwind and downwind of the fire site over a period of 3 days. The data collected by the TAGA unit was used by the local officials for a real time assessment of the airborne levels of HCl and Cl2.

Air Pollutants↗
PubMed1988

Chloride determination in serum by a flow-injection analysis precipitation pseudo-titration technique using a flow-through all-solid-state silver electrode.

A simply constructed, tubular, all-solid-state, flow-through silver electrode for flow-injection analysis (F.I.A.) is described. Use of a single line manifold accommodating the silver electrode, with a low level of silver ion (5 x 10(-4) M) in the carrier stream, is a useful method to determine chloride in serum, by means of a precipitation pseudo-titration F.I.A. technique. The sampling frequency is about 60/h.

Journal Article↗
PubMed2005

Trace anion determination in concentrated hydrofluoric acid solutions by two-dimensional ion chromatography I. Matrix elimination by ion-exclusion chromatography.

Since years, ion exclusion chromatography (ICE) has been the standard method to separate strong acid analyte anions from concentrated weak acid matrices such as hydrofluoric acid (HF). In this work, the commercially available IonPac ICE-AS 1 column was used to separate trace levels of chloride, nitrate, sulfate and phosphate from HF solutions at 20% (w/w). The efficiency of the separation was studied in more detail using techniques such as ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-mass spectrometry (ICP-MS). For 20% (w/w) HF solutions and at a water carrier flow-rate of 0.50 ml/min, the cut window was set from 8.5 to 14.5 min. Under these conditions, analyte recoveries of better than 90% were obtained for chloride, nitrate and sulfate, but only about 75% for phosphate. The HF rejection efficiency was better than 99.9%. It was found that the ICP techniques, measuring total element levels and not species, yielded significantly higher recoveries for phosphorus and sulfur compared to IC. Evidence will be given that part of the added phosphorus (approximately 15% for an addition of 10 mg PO4/kg) is present as mono-fluorophosphoric acid (H2FPO3). In the case of sulfate, the difference between IC and ICP-MS could be attributed to an important matrix effect from the residual HF concentration.

Algorithms↗
PubMed2006

Autoinducer-2-producing protein LuxS, a novel salt- and chloride-induced protein in the moderately halophilic bacterium Halobacillus halophilus.

The moderately halophilic bacterium Halobacillus halophilus carries a homologue of LuxS, a protein involved in the activated methyl cycle and the production of autoinducer-2, which mediates quorum sensing between certain species. luxS of H. halophilus is part of an operon that encodes an S-adenosylmethionine-dependent methyltransferase, a cysteine synthase, and a beta-cystathionine lyase. Expression of luxS was growth phase dependent, with maximal expression in the mid-exponential growth phase. In addition, transcription of luxS was strictly salt dependent; maximal mRNA concentrations were observed with 2.0 M NaCl in the growth medium. Chloride ions stimulated luxS transcription by a factor of three. Western blot analyses demonstrated a growth phase- and salinity-dependent production of LuxS. Moreover, cellular LuxS levels were strictly chloride dependent. Maximal accumulation of LuxS was observed at 0.5 to 1.0 M Cl(-) and depended on the salinity.

Amino Acid Sequence↗
PubMed1999

Time course of salinity adaptation in a strongly euryhaline estuarine teleost, fundulus heteroclitus: a multivariable approach

Freshwater-adapted killifish (Fundulus heteroclitus) were transferred directly from soft fresh water to full-strength sea water for periods of 1 h, 3 h, 8 h and 1, 2, 7, 14 and 30 days. Controls were transferred to fresh water for 24 h. Measured variables included: blood [Na+], osmolality, glucose and cortisol levels, basal and stimulated rates of ion transport and permeability of in vitro opercular epithelium, gill Na+/K+-ATPase and citrate synthase activity and chloride cell ultrastructure. These data were compared with previously published killifish cystic fibrosis transmembrane conductance regulator (kfCFTR) expression in the gills measured over a similar time course. Plasma cortisol levels peaked at 1 h, coincident with a rise in plasma [Na+]. At 8 h after transfer to sea water, a time at which previous work has shown kfCFTR expression to be elevated, blood osmolality and [Na+] were high, and cortisol levels and opercular membrane short-circuit current (Isc; a measure of Cl- secretion rate) were low. The 24 h group, which showed the highest level of kfCFTR expression, had the highest plasma [Na+] and osmolality, elevated plasma cortisol levels, significantly lower opercular membrane resistance, an increased opercular membrane ion secretion rate and collapsed tubule inclusions in mitochondria-rich cells, but no change in gill Na+/K+-ATPase and citrate synthase activity or plasma glucose levels. Apparently, killifish have a rapid (<1 h) cortisol response to salinity coupled to subsequent (8-48 h) expression of kfCFTR anion channel proteins in existing mitochondria-rich cells that convert transport from ion uptake to ion secretion.

Journal Article↗
PubMed1974

Analysis of hyperpolarizations induced by glutamate and acetylcholine on Onchidium neurones.

1. Four giant neurones, designated G-H cells, in the right pleural ganglion of the marine pulmonate mollusc, Onchidium verruculatum, showed characteristic membrane hyperpolarization during applications of either acetylcholine (ACh) or L-glutamate. In the presence of ACh the membrane was hyperpolarized only transiently, while in the presence of glutamate the response was maintained. Significant increases in membrane conductance accompanied the changes in membrane potential.2. In excess potassium sea water, a slight hyperpolarization occurred when the normal concentration was increased between one- and twofold. However, depolarization usually occurred when the concentration was increased tenfold except on a few occasions when a slight but definite hyperpolarization occurred. These changes were all accompanied by a substantial increase in the membrane conductance. This hyperpolarization was in all probability the result of an increase in chloride ion permeability caused by the release of an ACh-like transmitter from depolarized presynaptic nerve terminals.3. The reversal levels for glutamate- and ACh-induced hyperpolarization respectively were approximately - 20 and - 17 mV with respect to the resting membrane potential.4. By changing the external ion composition, glutamate- and ACh-induced hyperpolarization were shown to be the result of an increased permeability of the subsynaptic membrane to potassium and chloride ions respectively. It appears therefore that inhibition in the same G-H cells can be activated by two different transmitter substances and that each of them activates a change in the membrane permeability to a different ion.5. The relationship between the concentration of glutamate and the membrane conductance change was suggestive of two glutamate molecules reacting with a single receptor site.

Acetylcholine↗