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The effect of ambient chloride concentration changes on branchial chloride-bicarbonate exchanges and hemolymph acid-base balance of crayfish.

In crayfish Astacus leptodactylus maintained in 13 degrees C ambient water of constant oxygenation and acid-base balance, water chloride concentration was varied while the concentration of other ions, except sulfate, were maintained at constant values. The effects of wide variations of the ambient Cl- concentration, CCl, on the branchial titration alkalinity, delta TA, on delta CCl, delta CCO2, delta CO2 between inspired and expired water, and on the prebranchial hemolymph CCl and pH were studied. The branchial changes of TA, CCl and CCO2 were dependent on the ambient CCl, and a decrease of CCl led to a fall of CO2 excretion. Hemolymph acid-base balance closely depended on ambient CCl, particularly when CCl was less than 1 meq . L-1; when ambient CCl fell from 1 meq . L-1 to 0.1 meq . L -1, pH increased from 7.87 to 8.30. Since hemolymph PCO2 was not affected by the variations of CCl, the changes of pH are mainly explained by the concomitant changes of the hemolymph HCO3- and CO32- concentrations. During an 18-day exposure of crayfish to dechlorinated water, hemolymph CCl decreased progressively whereas its pH increased. The extreme values for CCl were 193 meq . L-1 at day 1 and 96 meq . L -1 at day 18, and the corresponding pH extremes were 7.87 and 8.65. Since the observed modifications of the branchial exchanges and the hemolymph acid-base balance were not related to the small changes of ambient osmolarity or of the SO42- or Na+ concentrations, it is inferred that they depended on a modified Cl-/HCO3- exchange mechanism in the gills.

Acid-Base Equilibrium↗

Genotoxic activities in vivo of cobaltous chloride and other metal chlorides as assayed in the Drosophila wing spot test.

A series of metal chlorides were subjected to the wing spot test of Drosophila melanogaster. In the test, larvae trans-heterozygous for the wing-hair mutations mwh and flr were orally treated at the third instar stage with a test compound and the wings were inspected at the adult stage for spots expressing phenotypes of the markers. CoCl2, MnCl2, MoCl3, NiCl2 and ZnCl2 were clearly effective in inducing spots with one or two mutant hairs (small spots). CoCl2 was clearly effective in inducing spots with three or more mutant hairs (large spots) as well. CrCl3, FeCl2 and FeCl3 were negative under the conditions used. Based on estimated frequencies of small spots induced at the LD50, the genotoxic effectiveness of the positive metal salts were ranked in a sequence of CoCl2 > ZnCl2 > MoCl3 > (MnCl2, NiCl2). Since CoCl2 did not induce large spots in the wings of the mwh/TM3 flies with a suppressed ability of mitotic crossing-over, the large spots induced by this compound in the mwh/flr system were ascertained as mutant clones due to mitotic crossing-overs.

Animals↗

Chloride transport blockers inhibit the chloride-dependent glutamate binding to rat brain membranes.

The effects of a series of chloride transport blockers (ethacrynate, furosemide, torasemide, 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene and diphenylcarboxylate) on Cl(-)-dependent L-[3H]glutamate (Glu) binding were tested in rat brain membranes, Cl-transport blockers inhibit the Ca2+/Cl(-)-induced increase in L-[3H]Glu binding, some of them without affecting the Ca2+/Cl(-)-independent L-[3H]Glu binding. Increasing the medium osmolarity by augmenting the sucrose concentration also inhibited the Ca2+/Cl(-)-induced increase in L-[3H]Glu binding. The effects of both sucrose and Cl-transport blockers were not additive, suggesting that they acted on the same type of mechanism. We recently suggested that L-[3H]Glu binding to brain membranes corresponds to Glu uptake in membrane vesicles. Therefore we propose that the Cl-transport blockers inhibit a Cl(-)-dependent Glu accumulation into these vesicles.

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

The effect of potassium dichromate and mercuric chloride on urinary excretion and organ and subcellular distribution of [203Hg]mercuric chloride in rats.

The mechanism by which subthreshold/non-effective doses or concentrations of potassium dichromate (K2Cr2O7) potentiate the effect of moderately effective dose/concentrations of mercuric chloride (HgCl2) on renal organic ion transport is not understood. To investigate this effect, the rate of excretion of mercury from the intact animal and the renal and hepatic accumulation and subcellular distribution of mercury within kidney cortex following pretreatment or in vitro exposure to K2Cr2O7 were undertaken. Coincidental administration of K2Cr2O7 had no significant effect in altering the rate of excretion of labeled mercury. Organ distribution showed time dependence; however, the presence of K2Cr2O7 did not increase renal mercury concentrations. In fact, significantly less mercury was found at 4 h in the kidneys of rats receiving both metal salts. Subcellular distribution of labeled mercury (203Hg) was also not significantly altered by the presence of K2Cr2O7, although the distribution patterns for in vitro exposure and pretreated tissues were different. These studies show that K2Cr2O7 does not produce alterations in urinary elimination, organ distribution or subcellular distribution of mercury.

Animals↗

Effect of ammonium chloride on the growth and metabolism of bovine ovarian granulosa cells and the development of ovine oocytes matured in the presence of bovine granulosa cells previously exposed to ammonium chloride.

Three experiments determined first, the effect of increasing ammonium chloride (NH(4)Cl) concentrations on the growth and metabolism of bovine granulosa cells isolated from small and medium-sized bovine ovarian follicles; secondly, whether the changes in granulosa cell growth and metabolism induced by NH(4)Cl were reversible; and thirdly, whether granulosa cells, previously conditioned with NH(4)Cl, were able to support maturation of oocytes in vitro. In Experiment 1, using a 2 (follicle size class) x 5 (NH(4)Cl concentration) factorial design, granulosa cells from small or medium-sized ovarian follicles were incubated for 96 h with 0, 0.2, 0.4, 0.8 or 1.6 micromol NH(4)Cl/ml. Experiment 2 used a split plot factorial design where granulosa cells were incubated for 96 h in the presence or absence of 1 micromol/ml NH(4)Cl and then incubated in the absence or presence of 1 micromol/ml NH(4)Cl for a further 48 h. Finally in Experiment 3, ovine oocytes were matured on layers of bovine granulosa cells which had not been conditioned with NH(4)Cl or conditioned with 0.5 or 1.0 micromol/ml NH(4)Cl and development of embryos to the blastocyst stage followed and blastocyst quality assessed. In Experiment 1, incubation of granulosa cells in increasing concentrations of NH(4)Cl reduced cell growth, increased cell protein concentrations and increased the amounts of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) oxidised and oestradiol and progesterone produced per 10(5) cells. Cells from medium-sized follicles were more sensitive to NH(4)Cl concentration and oxidised more MTT and produced less progesterone at high NH(4)Cl concentrations than cells from small-sized follicles. When, in Experiment 2, NH(4)Cl was removed from cell culture after 96 h incubation, cells previously exposed to NH(4)Cl grew at a slower rate during the subsequent 48 h, contained more cellular protein, oxidised more MTT and produced more oestradiol and progesterone than cells not previously exposed to NH(4)Cl. Maturation of ovine oocytes in coculture with bovine granulosa cells not exposed to NH(4)Cl (Experiment 3) increased egg cleavage rate and the proportion of cleaved eggs which developed to the blastocyst stage. Conditioning of granulosa cells with NH(4)Cl supported egg cleavage and development to the blastocyst stage at rates similar to those observed in the absence of granulosa cells. In conclusion, these experiments showed that the in vitro growth and metabolism of granulosa cells were altered by concentrations of NH(4)Cl similar to ammonium ion concentrations measured in follicular fluid and that these effects were not immediately reversible. Furthermore, the ability of granulosa cells conditioned with NH(4)Cl to support in vitro maturation of oocytes was impaired.

Ammonium Chloride↗

Chloride retention and release in a boreal forest soil: effects of soil water residence time and nitrogen and chloride loads.

The common assumption that chloride (Cl-) is conservative in soils and can be used as a groundwater tracer is currently being questioned, and an increasing number of studies indicate that Cl- can be retained in soils. We performed lysimeter experiments with soil from a coniferous forest in southeast Sweden to determine whether pore water residence time and nitrogen and Cl- loads affected Cl- retention. Over the first 42 days there was a net retention of Cl- with retention rates averaging 3.1 mg CI- m(-2) d(-1) (68% of the added Cl- retained over 42 days). Thereafter, a net release of Cl- at similar rates was observed for the remaining experimental period (85 d). Longer soil water residence time and higher Cl- load gave higher initial retention and subsequent release rates than shorter residence time and lower Cl- load did. Nitrogen load did not affect Cl transformation rates. This study indicates that simultaneous retention and release of Cl- can occur in soils, and that rates may be considerable relative to the load. The retention of Cl- observed was probably due to chlorination of soil organic matter or ion exchange. The cause of the shift between net retention and net release is unclear, but we hypothesize that the presence of O2 or the presence of microbially available organic matter regulates Cl- retention and release rates.

Adsorption↗

Low-dose mercuric chloride induces resistance in brown norway rats to further mercuric chloride by up-regulation of interferon-gamma.

Mercuric chloride induces autoimmunity in Brown Norway rats with polyclonal B-cell activation, hyper-IgE and multiple autoantibodies. Pre-treatment with low-dose HgCl2 (one-tenth of the standard dose) induces resistance to later full-dose HgCl2; we have studied the mechanism of this resistance. Brown Norway rats given low-dose HgCl2 showed only a modest increase in serum IgE level, three logs lower than rats given standard-dose HgCl2, and no up-regulation of splenic interleukin (IL)-4 mRNA. There was up-regulation of splenic interferon (IFN)-gamma gene expression and a progressive rise in serum IFN-gamma. Neither IL-12 nor IL-18 were induced, but there was up-regulation of IL-12 receptor beta2-chain (IL-12Rbeta2) expression. IL-10 and transforming growth factor (TGF)-beta expression did not change. Serum IgE and splenic IL-4 mRNA expression remained static when these rats were rechallenged, confirming resistance. Thereafter IFN-gamma expression gradually fell, after which IL-4 expression and serum IgE rose slightly. Our observations suggest that low-dose HgCl2 confers protection in Brown Norway rats to further HgCl2 by up-regulation of IFN-gamma, associated with enhanced IL-12Rbeta2 expression. The immunological response to HgCl2 in susceptible rat strains is more complex than previously appreciated and is dose dependent, with low doses inducing a T helper '(Th)1' type of response in contrast to the 'Th2' type response associated with standard doses.

Animals↗

Posttransfusion survival (24-hour) and hemolysis of previously frozen, deglycerolized RBCs after storage at 4 degrees C for up to 14 days in sodium chloride alone or sodium chloride supplemented with additive solutions.

BACKGROUND: Previously frozen human RBCs currently are glycerolized and deglycerolized by the use of open systems that limit storage of the deglycerolized RBCs at 4 degrees C to only 24 hours. STUDY DESIGN AND METHODS: Healthy male volunteers who met AABB requirements for blood donors (n = 38) were studied. A volume of 450 mL of blood was collected into CPDA-1. The RBC concentrates were stored at 4 degrees C for 3 to 6 days before being frozen with 40-percent (wt/vol) glycerol and stored at -80 degrees C. The RBCs were deglycerolized, resuspended in 0.9-percent sodium chloride and 0.2-percent glucose (SG) solution or SG solution supplemented with AS-1, AS-3, or AS-5, and stored in the resuspension medium at 4 degrees C for 14 days. RESULTS: The mean +/- SD freeze-thaw-wash process recovery was 90.0 +/- 4.0 percent for all 38 units. The mean 24-hour posttransfusion survival value was 79 percent for deglycerolized RBC stored at 4 degrees C for 7 days in SG alone, SG plus AS-3, or SG plus AS-5. Deglycerolized RBC that were stored at 4 C for 14 days in SG supplemented with AS-1, AS-3, or AS-5 had a mean 24-hour posttransfusion survival of 74 percent. After 7 days of storage of deglycerolized RBCs in SG alone, the mean hemolysis was 3. 7 percent. After 14 days of storage of deglycerolized RBCs in SG supplemented with AS-1, AS-3, or AS-5, the mean hemolysis was 2.5 percent. CONCLUSIONS: The levels of hemolysis did not correlate with the 24-hour posttransfusion survival values.

Adenine↗

Mechanism of chloride permeation in the cystic fibrosis transmembrane conductance regulator chloride channel.

The cystic fibrosis transmembrane conductance regulator (CFTR) functions as a Cl- channel important in transepithelial salt and water transport. While there is a paucity of direct structural information on CFTR, much has been learned about the molecular determinants of the CFTR Cl- channel pore region and the mechanism of Cl- permeation through the pore from indirect structure-function studies. The first and sixth transmembrane regions of the CFTR protein play major roles in forming the channel pore and determining its functional properties by interacting with permeating Cl- ions. Positively charged amino acid side-chains are involved in attracting negatively charged Cl- ions into the pore region, where they interact briefly with a number of discrete sites on the pore walls. The pore appears able to accommodate more than one Cl- ion at a time, and Cl- ions bound inside the pore are probably sensitive to one another's presence. Repulsive interactions between Cl- ions bound concurrently within the pore may be important in ensuring rapid movement of Cl- ions through the pore. Chloride ion binding sites also interact with larger anions that can occlude the pore and block Cl- permeation, thus inhibiting CFTR function. Other ions besides Cl- are capable of passing through the pore, and specific amino acid residues that may be important in allowing the channel to discriminate between different anions have been identified. This brief review summarizes these mechanistic insights and tries to incorporate them into a simple cartoon model depicting the interactions between the channel and Cl- ions that are important for ion translocation.

Animals↗

Both CFTR and outwardly rectifying chloride channels contribute to cAMP-stimulated whole cell chloride currents.

From whole cell patch-clamp recordings at 35 degrees C utilizing either nystatin perforation or conventional methods with 5 mM MgATP in the pipette solution, it was demonstrated that both cystic fibrosis transmembrane conductance regulator (CFTR) chloride (Cl-) channels and outwardly rectifying Cl- channels (ORCC) contribute to adenosine 3',5'-cyclic monophosphate (cAMP)-activated whole cell Cl- currents in cultured human airway epithelial cells. These results were similar whether recordings were performed on two normal human cell lines or on two cystic fibrosis (CF) cell lines stably complemented with wild-type CF gene. These results were obtained by exploiting dissimilar biophysical properties of CFTR and ORCC currents such as the degree of rectification of the current-voltage relationship, the difference in sensitivity to Cl- channel-blocking drugs such as 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), calixarenes, and diphenylamine carboxylic acid (DPC), and the opposing Cl- relative to I- permeabilities of the two channels. In normal cells or complemented CF cells, 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate stimulated outwardly rectifying whole cell Cl- currents. Addition of DIDS in the presence of cAMP inhibited the outwardly rectifying portion of the cAMP-activated Cl- current. The remaining cAMP-activated, DIDS-insensitive, linear CFTR Cl- current was inhibited completely by DPC. Additional results showed that not only do ORCC and CFTR Cl- channels contribute to cAMP-activated Cl- currents in airway epithelial cells where wild-type CFTR is expressed but that both channels fail to respond to cAMP in delta F508-CFTR-containing CF airway cells. We conclude that CFTR not only functions as a cAMP-regulated Cl- channel in airway epithelial cells but also controls the regulation of ORCC.

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

Discrimination of poly(vinyl chloride) samples with different plasticizers and prediction of plasticizer contents in poly(vinyl chloride) using near-infrared spectroscopy and neural-network analysis.

In the recycling of poly(vinyl chloride) (PVC), it is required to discriminate every plasticizer for quality control. For this purpose, the near-infrared spectra were measured for 41 kinds of PVC samples with different plasticizers (DINP, DOP, DOA, TOTM and Polyester) and different plasticizer contents (0-49%). A neural-network analysis was applied to the near-infrared spectra pretreated by second-derivative processing. They were discriminated from one another. The neural-network analysis also allowed us to propose a calibration model which predicts the contents of plasticizers in PVC. The correlation coefficient (R) and the root-mean-square error of prediction (RMSEP) for the DINP calibration model were found to be 0.999 and 0.41 wt%, respectively. In comparison, a partial least-squares regression analysis was carried out. The R and RMSEP of the DINP calibration model were calculated to be 0.993 and 1.27 wt%, respectively. It is found that a near-infrared spectra measurement combined with a neural-network analysis is useful for plastic recycling.

Conservation of Natural Resources↗

Potassium-coupled chloride cotransport controls intracellular chloride in rat neocortical pyramidal neurons.

Chloride (Cl(-)) homeostasis is critical for many cell functions including cell signaling and volume regulation. The action of GABA at GABA(A) receptors is primarily determined by the concentration of intracellular Cl(-). Developmental regulation of intracellular Cl(-) results in a depolarizing response to GABA in immature neocortical neurons and a hyperpolarizing or shunting response in mature neocortical neurons. One protein that participates in Cl(-) homeostasis is the neuron-specific K(+)-Cl(-) cotransporter (KCC2). Thermodynamic considerations predict that in the physiological ranges of intracellular Cl(-) and extracellular K(+) concentrations, KCC2 can act to either extrude or accumulate Cl(-). To test this hypothesis, we examined KCC2 function in pyramidal cells from rat neocortical slices in mature (18-28 d postnatal) and immature (3-6 d postnatal) rats. Intracellular Cl(-) concentration was estimated from the reversal potential of whole-cell currents evoked by local application of exogenous GABA. Both increasing and decreasing the extracellular K(+) concentration resulted in a concomitant change in intracellular Cl(-) concentration in neurons from mature rats. KCC2 inhibition by furosemide caused a change in the intracellular Cl(-) concentration that depended on the concentration of pipette Cl(-); in recordings with low pipette Cl(-), furosemide lowered intracellular Cl(-), whereas in recordings with elevated pipette Cl(-), furosemide raised intracellular Cl(-). In neurons from neonatal rats, manipulation of extracellular K(+) had no effect on intracellular Cl(-) concentration, consistent with the minimal KCC2 mRNA levels observed in neocortical neurons from immature animals. These data demonstrate a physiologically relevant and developmentally regulated role for KCC2 in Cl(-) homeostasis via both Cl(-) extrusion and accumulation.

Aging↗

Polymorphisms for vinyl chloride metabolism in French vinyl chloride workers.

Genetic polymorphisms of aldehyde dehydrogenase 2 (ALDH2) and cytochrome P450 2E1 (CYP2E1) have been shown to influence the degree of genetic damage in Taiwanese workers exposed to the carcinogen - vinyl chloride(VC). Certain French VC workers have been found to express biomarkers of mutant forms of cancer-related proteins (ras-p21 and p53) that have been related to their exposure. ALDH2 and CYP2E1 polymorphisms were investigated in 211 of these workers in an attempt to correlate differences in VC metabolic capacity with differences in the presence of these biomarkers. All of the workers were found to have the normal, wild-type ALDH2 gene, and none of them were found to be homozygous for the variant CYP2E1 allele. Sixteen workers were found to be heterozygous for the variant CYP2E1 allele. After adjusting for age, smoking, drinking and cumulative VC exposure, the odds ratio for the presence of either the mutant ras-p21 or the mutant p53 biomarker in these heterozygous workers was found to be statistically significantly increased in comparison to their homozygous, wild-type counterparts (OR = 5.05; 95% CI = 1.10-23.25). However, as opposed to the case in Taiwanese workers, these polymorphisms are relatively uncommon, and thus differences in ALDH2 and CYP2E1 can account for only a small proportion of the variability in mutagenic response to VC exposure in a Caucasian population.

Adult↗

Mitochondrial bioenergetics during the initiation of mercuric chloride-induced renal injury. II. Functional alterations of renal cortical mitochondria isolated after mercuric chloride treatment.

The mitochondrial functional defects occurring in the early stages of nephrotoxic renal injury secondary to mercuric chloride have been characterized. No loss of cellular integrity or major mitochondrial structural alterations occurred within the first 3 h after a subcutaneous injection of 5 mg/kg of HgCl2. At 3 h, levels of Hg2+ in renal cortex and isolated renal cortical mitochondria were 1.87 and 0.72 nmol/mg of protein, respectively. Much evidence suggested that this Hg2+ had reached the mitochondria in situ and not during the isolation process. Mitochondria isolated beginning 1 h after treatment with HgCl2 showed depressed ADP uptake. At 2 h, inhibitions of State 3 and 2,4-dinitrophenol uncoupled respiration were detected. Inhibition of 2,4-dinitrophenol-activated mitochondrial ATPase activity was present when measured on mitochondria isolated at 3 h. These effects were not reversed by 2 mM dithioerythritol, 50 mg/ml of albumin or 5 mM MgCl2. Analysis of the data in the context of information available on the in vitro effects of HgCl2 (Weinberg, J. M., Harding, P. G., and Humes, H. D. (1982) J. Biol. Chem. 257, 60-67) indicated that the mitochondrial functional effects could not be attributed to interaction of the mitochondria with Hg2+ during their isolation. These studies implicate compromised mitochondrial bioenergetic function as one of the earliest intracellular effects of Hg2+ in the production of nephrotoxicity but suggest that the intracellular process involves events in addition to those seen with direct exposure of mitochondria to Hg2+ in vitro.

Acid Phosphatase↗

Demonstration of mast cell granules by the cetylpyridinium chloride-acid dye (CPC-AD) and cetylpyridinium chloride-phosphotungstic acid (CPC-PTA) methods.

Cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CETAB) are bound to polyanionic substances by ionic bonds between the positively charged nitrogen of the quaternary salts and the negative groups of polyanions. The mast cell granules and some other structures treated with CPC or CETAB react selectively with acid dyes and fluorochromes. In ultrathin sections treated with CPC, phosphotungstic acid (PTA) greatly enhances the electron density of the granules of mast cells. The possible mechanism of acid dye and PTA binding by CPC or CETAB treated tissues is discussed.

Animals↗