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PubMed1995

Histamine chloramines have a persistent stimulating effect on histamine H2 receptors and gastric acid secretion.

Histamine plays an important role in the control of gastric acid secretion. Recently, chlorinated derivatives of histamine have been identified as having multiple effects on the intestinal tract. The aim of this study was to investigate the role of histamine chloramines on gastric acid secretion. We compared the effects of histamine and histamine chloramines on the histamine H2 receptors in vitro using guinea pigs and on gastric acid secretion in rats. With respect to the effects on histamine H2 receptors, histamine monochloramine showed agonist effects similar to those seen with histamine, but the agonist effects of histamine dichloramine were about half those of histamine. Unlike histamine effects, the histamine H2 receptor agonist effects of histamine monochloramine and histamine dichloramine did not disappear after repeated washout. With respect to the stimulation of gastric acid secretion in vivo, histamine monochloramine was similar to histamine, while the effect of histamine dichloramine was 42.2-52.7% of that of histamine. The recovery time to the basal secretory level after completion of stimulation by histamine chloramines was significantly prolonged compared with histamine. These results suggest that histamine chloramines, which bind strongly with histamine H2 receptors, may delay the termination of gastric acid secretion and increase the burden on the gastric and duodenal mucosa.

Animals↗
PubMed1985

A possible origin of chemiluminescence in phagocytosing neutrophils. Reaction between chloramines and H2O2.

A mixture of chloramines and hydrogen peroxide emits light. It was found that the reaction between taurine monochloramine and hydrogen peroxide is very slow. The stoichiometry of the reaction is 1:1 and taurine is detected as one of the products. The chlorinated proteins and bacteria, containing N-Cl groups, when reacting with hydrogen peroxide, are more effective in emitting light than low-molecular chloramines. Luminol enhances considerably light yield of the chloramine-hydrogen peroxide reaction. The chloramine-H2O2 reaction may account for light emitted by neutrophils during phagocytosis.

Chemical Phenomena↗
PubMed1984

alpha-Bungarotoxin aggregates on radioiodination with chloramine-T but not with iodogen.

The presence of polymer(s) of radioiodinated bungarotoxin (Bgt) in preparations iodinated with chloramine-T or with iodogen, was investigated by chromatography on Sephadex-G50. In addition to a monomeric peak (P2), chloramine-T preparations showed a high content of polymeric forms (16-43%) eluting in the void volume (P1), present only to the extent of 1-3% in iodogen preparations. In purified [125I]Bgt prepared by the iodogen method, the content of P1 increased on treatment with chloramine-T, in the absence of radioiodine. The nonspecific binding of [125I]Bgt to DE-81 filter discs was high in the case of chloramine-T preparations and proportional to the content of P1 in each batch. Purified P1 (polymer) but not P2 (monomer) showed a concentration-dependent high degree of binding to DE-81 discs.

Bungarotoxins↗
PubMed2004

Factors influencing inactivation of Klebsiella pneumoniae by chlorine and chloramine.

Inactivation of Klebsiella pneumoniae cultures by chlorine and chloramine was evaluated under different growth conditions by varying nutrient media dilution, concentrations of essential inorganic nutrients (FeCl3, MgSO4, phosphate, and ammonium salts), and temperature. All inactivation assays were performed at room temperature (22-23 degrees C) and near neutral pH (7.2-7.5). C*T(99.9) values for chlorine increased >20-fold and for chloramine increased 2.6-fold when cells were grown in 100-fold diluted nutrient broth (2NB) solutions (final TOC of 35-40 mg/L). Background levels of Mg: 6.75 x 10(-2) mM and Fe: 3.58 x 10(-5) mM or high levels of FeCl3 (0.01 mM) and MgSO4 (1 mM) during growth resulted in the highest resistances to chlorine with C*T(99.9) values of 13.06 (+/-0.91) and 13.78 (+/-1.97) mg-min/L, respectively. Addition of low levels of FeCl3 (0.001 mM) and MgSO4 (0.1 mM) to K. pneumoniae cultures during growth resulted in the lowest bacterial resistances to inactivation; C*T(99.9) values ranged from 0.28 (+/-0.06) to 1.88 (+/-0.53)mg-min/L in these cultures. Increase in growth temperature from 22.5 degrees C to 35 degrees C for unamended 2NB cultures resulted in a 42-fold decrease in C*T(99.9) values for chlorine. A similar change in temperature resulted in no significant change in C*T(99.9) values for chloramine. These results indicate that inactivation of K. pneumoniae cultures by chlorine was highly sensitive to changes in growth conditions unlike inactivation by chloramine.

Chloramines↗
PubMed1998

Chloramine T-induced structural and biochemical changes in echistatin.

Echistatin is a member of the disintegrin family of peptides and a potent inhibitor of platelet aggregation and cell adhesion. Echistatin binds to integrin alpha(v)beta3 and alpha(IIb)beta3 receptors with high affinity. Binding is mediated by an RGD-containing loop maintained in an appropriate conformation by disulfide bridges. In this study, we have compared the binding characteristics of echistatin iodinated by either lactoperoxidase or chloramine T method. We show that echistatin labeled by lactoperoxidase method binds to integrin alpha(v)beta3 receptor with high affinity and in a non-dissociable manner very similar to native echistatin. In contrast, chloramine T-labeled echistatin can rapidly dissociate from the receptor. We demonstrate that chloramine T reaction results in the addition of an extra oxygen to the methionine residue adjacent to the RGD motif in echistatin. Modeling studies and molecular dynamic simulation studies show that the extra oxygen atom on the methionine residue can form hydrogen bonds with the glycine and aspartic acid residues of the RGD motif. These structural changes in echistatin help explain the changes in the binding characteristics of the molecule following chloramine T reaction.

Chloramines↗
PubMed2003

Diversity of nitrifying bacteria in full-scale chloraminated distribution systems.

Chloramination for secondary disinfection of drinking water often promotes the growth of nitrifying bacteria in the distribution system due to the ammonia introduced by chloramine formation and decay. This study involved the application of molecular biology techniques to explore the types of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) present in several full-scale chloraminated systems. The results of AOB community characterization indicated the ubiquitous detection of representatives from the Nitrosomonas genus, with Nitrosospira constituting a negligible or small fraction of the AOB community in all but one sample. Cloning and sequencing demonstrated the presence of AOB representatives within the Nitrosomonas oligotropha cluster, a phylogenetic subgroup of AOB from which isolates demonstrate a high affinity for ammonia. For the NOB communities, Nitrospira were detected in most of the samples, while Nitrobacter were only detected in a few samples. These results provide insight into the types of AOB responsible for nitrification episodes in full-scale chloraminated systems, which should help direct future studies aimed at characterizing relevant AOB growth and inactivation properties. Furthermore, the detection of NOB in most of the samples suggests a need to evaluate the contribution of biological nitrite oxidation relative to chemical oxidation in these systems.

Ammonia↗
PubMed2003

Disinfection efficacy of organic chloramines.

The disinfection efficacies of model organic chloramines were investigated. Twenty amino acids and two nucleic acid bases were chlorinated separately with sodium hypochlorite at a Cl:N molar ratio of 0.4:1, and were then used to treat an E. coli suspension for 60 min. DPD/FAS titration was carried out to obtain the concentration of the chlorinated nitrogenous organic compounds as a function of time. In addition, membrane introduction mass spectrometry (MIMS) was used to quantify inorganic chloramines (mono-, di-, and trichloramine). The results of these experiments showed that the organic chloramines examined in this research had little or no effect on the viability of E. coli. MIMS analyses demonstrated that there was no quantifiable formation of inorganic chloramines when the organic nitrogen compounds were chlorinated.

Amino Acids↗
PubMed1997

Neutrophil antioxidant capacity during the respiratory burst: loss of glutathione induced by chloramines.

Low-molecular weight antioxidants in rat peritoneal neutrophils undergo rapid redox recycling, so measurements were made of their initial content and subsequent changes during the respiratory burst, when superoxide formation is maximized. Endogenous vitamin E, ascorbate and total glutathione (reduced + oxidized) were not significantly changed during 30 min of respiratory burst, which was stimulated by phorbol 12-myristate 13-acetate (PMA). When de novo synthesis of glutathione was inhibited by buthionine-[S,R] sulfoximine (BSO), the glutathione content rapidly decreased in activated neutrophils but not in resting cells. The lost total glutathione was recovered neither from the incubation medium nor as a protein-bound form, which suggests that irreversible oxidation of glutathione occurs. Furthermore, the glutathione loss continues even 30 min after PMA stimulation, when the respiratory burst has almost ceased. The decrease of glutathione was prevented by added catalase, or by addition of NaN3 or KCN which inhibits myeloperoxidase (MPO). Superoxide dismutase had no protective effects. These findings suggest the involvement of an MPO-H2O2-halide system in the accelerated consumption of glutathione during the respiratory burst. Additional studies showed that neutrophil-derived chloramines found in the extracellular medium could lead to intracellular glutathione loss. Incubation of resting cells with chemically produced membrane permeable monochloramine in the presence of BSO resulted in a decrease of glutathione, whereas membrane-impermeable taurine-chloramine was less effective. We conclude that chloramines are responsible for accelerated glutathione turnover in neutrophils during the respiratory burst. Permeable extracellular chloramines derived from the respiratory burst activity, such as monochloramine, can reenter cells and react with thiols.

Animals↗
PubMed2005

Population diversity in model potable water biofilms receiving chlorine or chloramine residual.

Most water utilities use chlorine or chloramine to produce potable water. These disinfecting agents react with water to produce residual oxidants within a water distribution system (WDS) to control bacterial growth. While monochloramine is considered more stable than chlorine, little is known about the effect it has on WDS biofilms. Community structure of 10-week old WDS biofilms exposed to disinfectants was assessed after developing model biofilms from unamended distribution water. Four biofilm types were developed on polycarbonate slides within annular reactors while receiving chlorine, chloramine, or inactivated disinfectant residual. Eubacteria were identified through 16S rDNA sequence analysis. The model WDS biofilm exposed to chloramine mainly contained Mycobacterium and Dechloromonas sequences, while a variety of alpha- and additional beta-proteobacteria dominated the 16S rDNA clone libraries in the other three biofilms. Additionally, bacterial clones distantly related to Legionella were found in one of the biofilms receiving water with inactivated chlorine residual. The biofilm reactor receiving chloraminated water required increasing amounts of disinfectant after 2 weeks to maintain chlorine residual. In contrast, free chlorine residual remained steady in the reactor that received chlorinated water. The differences in bacterial populations of potable water biofilms suggest that disinfecting agents can influence biofilm development. These results also suggest that biofilm communities in distribution systems are capable of changing in response to disinfection practices.

Bacteria↗
PubMed1976

Chloramine mutagenesis in Bacillus subtilis.

Chloramine (which occurs widely as a by-product of sanitary chlorination of water supplies) is shown to be a weak mutagen, when reversion of trpC to trpC in Bacillus subtilis is used as an assay. Some DNA-repair mutants appear to be more sensitive to chloramine, suggesting the involvement of DNA targets in bactericide. The influence of plating media on survival of cells treated with chloramine suggests a bacterial repair system acting upon potentially lethal lesions induced by chloramine.

Bacillus subtilis↗
PubMed1977

Iodination of staphylococcal enterotoxin B by use of chloramine-T.

This report describes the conditions that are necessary for iodination of staphylococcal enterotoxin B (SEB) by use of chloramine-T. Makor Chemical Co. SEB and the two major SEB components, which were prepared by isoelectric focusing of partially purified SEB, were used in these studies. The antigenic activity of the SEB preparations was monitored by radioimmunoassay as the oxidation/reduction (O/R) potential was increased by addition of chloramine-T. The SEB preparations lost antigenic activity rapidly at pH 7.5 and room temperature when sufficient chloramine-T was added to raise the O/R potential above 250 mV. Iodinated SEB with satisfactory immunoreactivity was prepared by omitting carrier iodide from the iodination reaction mixture and by using at least 1 mg of SEB/ml, steps which made the O/R potential more stable, and by stopping the reaction before the O/R potential exceeded 250 mV. Comparison of the chloramine-T method with a lactoperoxidase/H2O2 method of iodinating SEB showed the latter to cause a greater loss of immunoreactivity.

Chloramines↗
PubMed2002

Ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system.

Nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. The diversity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene (ribosomal DNA [rDNA]) cloning and sequencing. For ammonia oxidizers, 16S rDNA-targeted T-RFLP indicated the presence of Nitrosomonas in each of the distribution systems, with a considerably smaller peak attributable to Nitrosospira-like AOB. Sequences of AOB amplification products aligned within the Nitrosomonas oligotropha cluster and were closely related to N. oligotropha and Nitrosomonas ureae. The nitrite-oxidizing communities were comprised primarily of Nitrospira, although Nitrobacter was detected in some samples. These results suggest a possible selection of AOB related to N. oligotropha and N. ureae in chloraminated systems and demonstrate the presence of NOB, indicating a biological mechanism for nitrite loss that contributes to a reduction in nitrite-associated chloramine decay.

Ammonia↗
PubMed1986

Inhibition of neutrophil killing of Candida albicans pseudohyphae by substances which quench hypochlorous acid and chloramines.

Using a microtiter plate killing assay, we investigated the in vitro killing of Candida albicans by human neutrophils and by hypochlorous acid/hypochlorite ion (HOCl/OCl-) or chloramine solutions to evaluate the inhibition of this process by quenchers of these oxidants. Methionine, tryptophan, and alanine were able to effectively inhibit neutrophil killing of candida pseudohyphae. These substances were capable of quenching the oxidant activity of NaOCl, monochloramine (NH2Cl), and to a lesser extent, taurine chloramine. NaOCl and NH2Cl were able to kill C. albicans in the absence of inhibitors in concentrations of less than 5 microns M, whereas greater than 100 microns M taurine chloramine was required for killing. Methionine and tryptophan were capable of markedly inhibiting killing by all three oxidants, whereas alanine affected only killing by NaOCl. The oxidant activity of NaOCl was more readily quenched by opsonized or unopsonized Candida yeast than was the oxidant activity of either NH2Cl or taurine chloramine. These results suggest that some substances which quench the oxidizing activity of the products of the neutrophil myeloperoxidase system can inhibit the killing of C. albicans by these cells.

Alanine↗
PubMed2006

Photoreactivation of Escherichia coli following medium-pressure ultraviolet disinfection and its control using chloramination.

Ultraviolet (UV) disinfection is becoming increasingly popular as an alternative disinfection technology to chlorination in recent years. In this study, we investigated the photoreactivation of Escherichia coli following medium-pressure (MP) UV disinfection of synthetic water by a bench-scale collimated beam apparatus. The UV doses ranged from 1.6 -19.7 mWs/cm2 and photoreactivation was investigated for 6 hours under fluorescent light. In addition, chloramination was applied after UV disinfection to investigate its ability to control photoreactivation. It was found that photoreactivation occurred for all UV doses tested and the increase in bacteria numbers ranged from 0.04 to 1.35 log10. However, the degree of photoreactivation decreased with increased UV doses. Chloramination experiments revealed that the addition of 0.5 mg/l of monochloramine resulted in suppression of photoreactivation for 1 hour only. An increased monochloramine dose of 1 mg/l was found to prevent photoreactivation for the entire duration of the experiment. The results of this study have shown that photoreactivation occurs even after MP UV disinfection, although it is of a lesser extent at higher UV doses. This study has also established that secondary chloramination can effectively suppress and eliminate photoreactivation with a chloramine dose of 1 mg/l.

Atmospheric Pressure↗
PubMed1986

Role of hypochlorous acid and chloramines in the extracellular cytolysis by neutrophil polymorphonuclear leukocytes.

The lysis of human red blood cells (HRBC) by neutrophil polymorphonuclear leukocytes (PMN), triggered with opsonized zymosan (OPZ) particles, was inhibited by azide, catalase, Cl- -free medium and amino acids indicating the involvement of myeloperoxidase (MPO), hydrogen peroxide (H2O2), Cl- ions and hypochlorous acid (HOCl) respectively. Thus, the cytolytic process depends on the following reaction: (Formula: see text). Because the oxidizing agent HOCl is also the precursor of the chloramines, a group of oxidants formed by the reaction between HOCl and PMN-derived ammonia (NH4+) or amines (R-NH2), the observed HRBC lysis can be theoretically due to HOCl and/or chloramines. Nevertheless, we found that PMN-mediated cytotoxicity occurs as an unidirectional process, being HRBC targets lysed and PMN unaffected. This finding indicates that the cytotoxin must be relatively more efficient against HRBC as compared with PMN. In fact, reagent HOCl (used at concentrations comparable to those generated by PMN) but not chloramines displayed such a type of property. Taken together, the data suggest that HRBC are killed by PMN-derived HOCl without the requirement for chloramines: this implies that NH4+ and R-NH2, released by PMN, act as down-modulators of the cytotoxic process, serving as HOCl trapping agents.

Animals↗
PubMed1983

Granular activated carbon usage in chloramine removal from dialysis water.

Chloramines, oxidant compounds used in municipal drinking water as sanitizing agents, potentiate hemolytic anemia when present in dialysate. Thus far, the addition of ascorbic acid to the dialysate and the use of granular activated carbon (GAC) have been the only reliable, practical methods reported for removing chloramines. This is a report on the bench-scale testing of five kinds of GAC from three manufacturers. The performance of 100 g of each carbon was studied in a 2-in-diameter column through which feed-water containing approximately 1.5 mg/L chloramines flowed downward at an average volumetric rate of 140 ml/min. The carbons' experimental capacities for chloramines differed by as much as one order of magnitude. The experimental results were used to estimate the capacity of a 9-in-diameter, 45-in-tall column of the best carbon. These scale-up estimations indicate that this sorbent may safely last through 156 5-h dialyses.

Anemia, Hemolytic↗
PubMed1978

Prolactin receptors: a comparison between chloramine-T and lactoperoxidase iodination.

The binding properties of chloramine-T iodinated oPRL (using a modified iodination procedure) to prolactin receptors of female rat liver membrane particles were compared with those of lactoperoxidase iodinated oPRL. The results indicated that both iodination methods provided 125I-oPRLs which were suitable for receptor binding studies. Our results suggested that chloramine-T 125I-oPRL was even better than lactoperoxidase 125I-oPRL in terms of lower nonspecific binding. The chloramine-T iodinated oPRL was used to study the prolactin receptors in rat ovaries and DMBA induced rat mammary tumors. The results showed that the amount of prolactin receptors in rat ovaries was related to the plasma level of prolactin as it had been reported in liver by other investigators. The study of prolactin receptors in rat mammary tumors indicated that the prolactin receptor content of hormone dependent mammary tumors was much higher than that of hormone independent mammary tumors.

Animals↗
PubMed1994

Modulation of voltage-dependent inactivation of the inwardly rectifying K+ channel by chloramine-T.

The inwardly rectifying K+ channel (IK1) exhibits voltage-dependent inactivation at membrane voltages more negative than approximately -140 mV. The effect of chloramine-T on the inactivation of IK1 was examined in guinea-pig ventricular myocytes using the patch-clamp technique. Chloramine-T (2 mM) irreversibly inhibited the time-dependent decay of whole-cell IK1 inactivation. As a result, the negative slope region of the current-voltage (I-V) relationship was abolished. In cell-attached single channel recordings, the number of active channels in the patch decreased with time during the voltage-clamp step to the K+ equilibrium potential (EK) of -100 mV. Chloramine-T prevented this time-dependent decrease in channel number, and ensemble averaged currents exhibited abolishment of time-dependent decay of channel activity at EK -100 mV. These results suggest that the hyperpolarization-induced inactivation of cardiac IK1 is controlled by voltage-dependent intrinsic gating.

Animals↗