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PubMed1988

Comparative radiolabeling and distribution of a tumour-directed monoclonal antibody.

The monoclonal antibody (MAb) 155H.7, raised against a synthetic beta-anomer of the Thomsen-Friedenreich antigen (S-TAG), was radioiodinated using iodine monochloride, chloramine-T and Iodogen and radiolabeled with 111In using the bromoacetamido-derivative of benzyl-EDTA. The in vitro immunoreactivity of the MAb was assessed using an ELISA with the S-TAG and the in vivo distribution of the radioiodinated and radiochelated MAb was determined in the murine mammary carcinoma TA3/Ha tumour model. Both chloramine-T and iodine monochloride radioiodination greatly reduced the immunoreactivity of the MAb compared to radioiodination using Iodogen. Bifunctional chelate labeling was comparable to Iodogen in reducing the immunoreactivity of the MAb and subsequent chelation of 111In did not further compromise the immunoreactivity of the MAb. The in vivo distribution data showed significantly different distributions of the radiolabels after injection of the radioiodinated and radiochelated MAb. The 131I-MAb showed some tumour association as compared to the distribution of an 125I-non-specific protein and the data also indicates that there is preferential dehalogenation of the radioiodinated MAb. 111In from the radiochelated MAb showed significantly higher uptake in the tumour than 131I from the 131I-MAb. It is suggested that the differing fates of the two radiolabels within the tumour cell is responsible for the difference in retention observed and not necessarily due to the lack of MAb uptake by the tumour. Overall, the radiochelate label for MAb 155H.7 appears to be superior to radioiodine for in vivo use.

Animals↗
PubMed2005

Bromination and chlorination reactions of myeloperoxidase at physiological concentrations of bromide and chloride.

Myeloperoxidase and eosinophil peroxidase use hydrogen peroxide to oxidize halides and thiocyanate to their respective hypohalous acids. Myeloperoxidase produces mainly hypochlorous acid and hypothiocyanite. Hypobromous acid and hypothiocyanite are the major products of eosinophil peroxidase. We have investigated the ability of myeloperoxidase to produce hypobromous acid in the presence of physiological concentrations of chloride and bromide. In accord with previous studies, between pH 5 and 7, myeloperoxidase converted about 90% of available hydrogen peroxide to hypochlorous acid and the remainder to hypobromous acid. Above pH 7, there was an abrupt rise in the yield of hypobromous acid. At pH 7.8, it accounted for 40% of the hydrogen peroxide. Bromide, at physiological concentrations, promoted a dramatic increase in bromination of human serum albumin catalyzed by myeloperoxidase. The level of 3-bromotyrosine increased to 16-fold greater than that for 3-chlorotyrosine. Chlorination of tyrosyl residues was not affected by bromide. With reagent hypohalous acids, bromination of tyrosyl residues was considerably more facile than chlorination. Hypochlorous acid promoted bromination to only a limited extent, which ruled out transhalogenation as a substantive route to 3-bromotyrosine. Chloramines and bromamines were also formed on albumin. Bromamines decayed much faster than chloramines and rapidly gave rise to protein carbonyls. We conclude that at physiological concentrations of chloride and bromide, hypobromous acid can be a major oxidant produced by myeloperoxidase. Its production in vivo will depend on pH and the concentration of bromide. Once produced, hypobromous acid will react with proteins to form bromamines, carbonyls, and brominated tyrosine residues. Consequently, 3-bromotyrosine should be considered as an oxidative product of myeloperoxidase and cannot be used as a specific biomarker for eosinophil peroxidase.

Body Fluids↗
PubMed2004

Supplementary taurine may stabilize atheromatous plaque by antagonizing the activation of metalloproteinases by hypochlorous acid.

The rupture of atherosclerotic plaque, responsible for triggering the majority of myocardial infarctions, presumably requires proteolysis of collagen fibers and other protein components of the intercellular matrix. This is achieved by activated matrix metalloproteases (MMPs) secreted by intimal macrophages and foam cells. MMPs are synthesized as inactive pro-enzymes in which coordinate binding of the thiol group of a key cysteine residue to the active-site zinc atom blocks proteolytic activity. Physiological activation of MMPs is mediated, in large measure, by phagocyte-derived hypochlorous acid (HOCL), which can oxidize the zinc-bound thiol to sulfinic acid, thus freeing the active-site zinc. HOCL also encourages proteolysis of ground substance by inactivating proteins such as TIMP-1 that are physiological inhibitors of MMPs. In vivo, the unrestrained oxidant activity of HOCL is opposed by taurine, which reacts spontaneously with HOCL to generate taurine chloramine, much more stable than HOCL. Taurine chloramine has less impact than HOCL on MMP activation, and does not impair the activity of TIMP-1. Since tissue levels of taurine can be boosted via supplementation, taurine may thus have potential for stabilizing plaque and thereby warding off infarction--an effect that should be reinforced by taurine's platelet-stabilizing activity. In light of recent epidemiological evidence that increased expression of myeloperoxidase - the enzyme which generates HOCL--is an important risk factor for coronary disease, supplemental taurine may indeed have broader utility for suppressing both the genesis and the rupture of atherosclerotic plaque.

Arteriosclerosis↗
PubMed2004

Modification of low-density lipoprotein by different radioiodination methods.

Scintigraphic imaging of radiolabeled low-density lipoproteins (LDL) is an interesting tool for the understanding of its role in pathomechanism of atherosclerosis. Metabolism of native LDL shows quite different pattern and kinetics as compared to that of modified LDL which is not mediated by classical LDL-receptor and accumulates in atherosclerotic lesions to form lipid-laden foam cells. Therefore we were interested whether radiolabelling of LDL induces structural modifications. We performed the iodine labeling of LDL for scintigraphic imaging of atherosclerosis by three different methods: chloramine-T (A), iodine monochloride (B) and iodogen (C). The highest radiolabelling yield of (125)I was obtained by the iodogen method (75.44+/-13.52%) and the lowest (49.01+/-12.74%) by iodine monochloride. Chloramine T showed a labeling yield of 62.82+/-6.17%. The stability of the tracer was very high with all the methods, persisting up to 6 h (98.83+/-1.2% - 91.38+/-4.7%, 15 min vs 6 h after labeling). For the first time we not only investigated the influence of radiolabelling on relative electrophoretic mobility (REM), but also various oxidation parameters such as baseline dienes (BD), thiobarbituric acid reactive substances (TBARS), endogenous peroxides (POX) and oxidation resistance in the copper-mediated oxidation system (expressed as lag-time) were measured. Furthermore, oxidation- derived fragmentation of the lipoproteins was examined with SDS-PAGE electrophoresis. Data are expressed as % change compared to native LDL before radiolabeling. BD were reduced by 32% using the method (A), but increased by 33% and 47% with the monochloride (B) and iodogen method (C), respectively. The effect on lag-time was comparable for all the three methods, ranging from 25 to 36% reduction in lag-time. TBARS were strongly increased 5-7 fold by all the methods. REM was changed by all three methods. While by methods A and C we have found a moderate increase in REM by 1.75 and 2.0 fold, respectively, and no fragmentation of Apo B was observed, in contrast by method B a dramatic 4.5 fold increase in REM was found. SDS-PAGE-electrophoresis showed strong fragmentation of the apoB only for method B. We conclude, that iodine labeling of LDL induces significant modification of the molecule. Once modified, LDL no longer reflects the native molecule, exhibiting altered functional properties. Using radiolabeled LDL this fact should be considered.

Drug Evaluation, Preclinical↗
PubMed2005

Formation of nitrosodimethylamine (NDMA) during chlorine disinfection of wastewater effluents prior to use in irrigation systems.

The probable human carcinogen nitrosodimethylamine (NDMA) is produced when wastewater effluent is disinfected with chlorine. In systems where wastewater effluent is used for landscape or crop irrigation, relatively high chlorine doses (i.e., up to 2,000,mg-min/L) are often used to ensure adequate disinfection and to minimize biofouling in the irrigation system. To assess the formation of NDMA in such systems, samples were collected from several locations in full-scale wastewater treatment systems and their associated irrigation systems. Up to 460 ng/L of NDMA was produced in full-scale systems in which chloramines were formed when wastewater effluent was disinfected with chlorine in the presence of ammonia. Less than 20 ng/L of NDMA was produced in systems that used free chlorine (i.e., HOCl/OCl(-)) for disinfection in the absence of ammonia. The production of NDMA in ammonia-containing systems was correlated with the concentration of NDMA precursors in the wastewater effluent and the overall dose of chlorine applied. Much of the NDMA formation occurred in chlorine contact basins or in storage basins where water that contained chloramines was held after disinfection. When landscape or crop irrigation is practiced with ammonia-containing wastewater effluent, NDMA production can be controlled by use of lower chlorine doses or by application of alternative disinfectants.

Agriculture↗
PubMed2006

The effect of advanced treatment on chlorine decay in metallic pipes.

Experiments were run to measure what effect advanced treatment might have on the kinetics of chlorine and chloramine decay in metallic pipes that comprise many drinking water distribution systems. A recirculating loop of 6-in diameter unlined ductile iron pipe was used to simulate turbulent flow conditions in a pipe with significant corrosion and tubercle buildup. Conventionally treated test water was subjected to either ozonation, carbon adsorption (GAC), reverse osmosis (RO) or no further treatment before being chlorinated and introduced into the pipeline simulator. Results showed that overall chlorine decay in the simulator was consistently dominated by wall reactions whose first-order rate constants were an order of magnitude higher than those for the bulk water. With free chlorine, the wall rate constants for ozonated and GAC-treated water were about twice those of conventional or RO-treated water. This behavior is believed due to the effect that changes in the organic content of water have on its ability to complex iron and the effect that changes in water conductivity have on pipe wall corrosion. Tests run with chloraminated water showed no statistically significant effect of treatment type and had wall rate constants that were only 40 to 70% as high as those using free chlorine.

Chlorine↗
PubMed1992

Voltage-sensitive and solvent-sensitive processes in ion channel gating. Kinetic effects of hyperosmolar media on activation and deactivation of sodium channels.

Kinetic effects of osmotic stress on sodium ionic and gating currents have been studied in crayfish giant axons after removal of fast inactivation with chloramine-T. Internal perfusion with media made hyperosmolar by addition of formamide or sucrose, reduces peak sodium current (before and after removal of fast inactivation with chloramine-T), increases the half-time for activation, but has no effect on tail current deactivation rate(s). Kinetics of ON and OFF gating currents are not affected by osmotic stress. These results confirm (and extend to sodium channels) the separation of channel gating mechanisms into voltage-sensitive and solvent-sensitive processes recently proposed by Zimmerberg J., F. Bezanilla, and V. A. Parsegian. (1990. Biophys. J. 57:1049-1064) for potassium delayed rectifier channels. Additionally, the kinetic effects produced by hyperosmolar media seem qualitatively similar to the kinetic effects of heavy water substitution in crayfish axons (Alicata, D. A., M. D. Rayner, and J. G. Starkus. 1990. Biophys. J. 57:745-758). However, our observations are incompatible with models in which voltage-sensitive and solvent-sensitive gating processes are presumed to be either (a) strictly sequential or, (b) parallel and independent. We introduce a variant of the parallel model which includes explicit coupling between voltage-sensitive and solvent-sensitive processes. Simulations of this model, in which the total coupling energy is as small as 1/10th of kT, demonstrate the characteristic kinetic changes noted in our data.

Animals↗
PubMed2002

Occurrence of nitrifying bacteria and nitrification in Finnish drinking water distribution systems.

Microbiological nitrification process may lead to chemical, microbiological and technical problems in drinking water distribution systems. Nitrification activity is regulated by several physical, and chemical, and operational factors. However, the factors affecting nitrification in the distribution systems in boreal region, having its specific environmental characteristics, are poorly known. We studied the occurrence and activity of nitrifying bacteria in 15 drinking water networks distributing water with very different origin and treatment practices. The waters included chloraminated surface water, chlorinated surface water, and non-disinfected groundwater. The networks were located in eight towns in different parts of Finland. Our results showed that nitrifying bacteria are common in boreal drinking water distribution systems despite their low temperature. Surprisingly high numbers and activities of nitrifiers were detected in pipeline sediment samples. The numbers of ammonia-oxidizing bacteria and their oxidation potentials were highest in chloraminated drinking water delivering networks, whereas the nitrite-oxidizing bacteria were present in the greatest numbers in those networks that used non-disinfected groundwater. The occurrence of nitrifying bacteria in drinking water samples correlated positively with the numbers of heterotrophic bacteria and turbidity, and negatively with the content of total chlorine. Although nitrifying bacteria grew well in drinking water distribution systems, the problems with nitrite accumulation are rare in Finland.

Ammonia↗
PubMed2003

Trihalomethane formation by chlorination of ammonium- and bromide-containing groundwater in water supplies of Hanoi, Vietnam.

The occurrence and the fate of trihalomethanes (THMs) in the water supply system of Hanoi City, Vietnam was investigated from 1998 to 2001. The chlorination efficiency, THM speciation, and, THM formation potential (THMFP) was determined in the water works and in tap water. With regard to THM formation, three types of groundwater resources were identified: (I) high bromide, (II) low bromide, and (III) high bromide combined with high ammonia and high dissolved organic carbon (DOC) concentrations. Under typical treatment conditions (total chlorine residual 0.5-0.8 mg/L), the total THM formation was always below WHO, EU, and USEPA drinking water standards and decreased in the order type I > type II > type III, although the THMFP was > 400 micrograms/L for type III water. The speciation showed > 80% of bromo-THMs in type I water due to the noticeable high bromide level (< or = 140 micrograms/L). In type II water, the bromo-THMs still accounted for some 40% although the bromide concentration is significantly lower (< or = 30 micrograms/L). In contrast, only traces of bromo-THMs were formed (approximately 5%) in type III water, despite bromide levels were high (< or = 240 micrograms/L). This observation could be explained by competition kinetics of chlorine reacting with ammonia and bromide. Based on chlorine exposure (CT) estimations, it was concluded that the current chlorination practice for type I and II waters is sufficient for > or = 2-log inactivation of Giardia lamblia cysts. However, in type III water the applied chlorine is masked as chloramine with a much lower disinfection efficiency. In addition to high levels of ammonia, type III groundwater is also contaminated by arsenic that is not satisfactory removed during treatment. N-nitrosodimethylamine, a potential carcinogen suspected to be formed during chloramination processes, was below the detection limit of 0.02 microgram/L in type III water.

Ammonia↗
PubMed2002

Disinfection by-products in Finnish drinking waters.

Disinfection by-products (DBPs) were measured in plant effluents of 35 Finnish waterworks, which utilized different treatment processes and raw water sources. DBPs were measured also from the distribution systems of three waterworks. Di- and trichloroacetic acids, and chloroform were the major DBPs found in treated water samples. The concentration of six haloacetic acids (HAA6) exceeded the concentrations of trihalomethanes (THMs). Chlorinated drinking waters (DWs) originating from surface waters contained the highest concentration of HAA6 and THMs: 108 and 26 microg/l, respectively. The lowest concentrations of DBPs were measured from ozonated and/or activated carbon filtrated and chloraminated DWs. Higher concentrations of HAA6, THMs, and adsorbable organic halogens were measured in summer compared to winter. The levels of chlorinated acetic acids, chloroform, and bromodichloromethane correlated positively with mutagenicity. Past mutagenicity levels of DWs were examined. A major reduction in the use of prechlorination, increased use of chloramine disinfection, and better removal of organic carbon were the most important reasons for the 69% decrease in mutagenicity from 1985 to 1994.

Chlorine Compounds↗
PubMed1981

Chlorine, is there a better alternative?

In brief, the current status of our present knowledge regarding alternatives to free chlorine is as follows: 1. Biocidal Capabilities - Ozone is the most potent biocide of those under consideration. Chlorine dioxide is about on a par with hypochlorous acid, the most efficient form of free residual chlorine. Chlorine dioxide, in contrast to free residual chlorine, increases in efficiency as pH increases above 6. Chloramine is a much weaker biocide than hypochlorite ion, the least inefficient form of free residual chlorine. 2. Health effects - All of the potential alternatives may cause some adverse health effects. Chlorite and chlorate, two of the reaction products of chlorine dioxide, have been shown to cause a subclinical apparently compensated hemolytic anemia in rats. On the other hand, according to very preliminary studies, chlorine and all of the alternatives except chlorine dioxide have been shown to produce reaction products from substances in water that can initiate tumors in mice. Actually, all disinfectants are reactive molecules capable of altering the chemical nature of organic substances present in the water. Thus, the alternative disinfectants question relates to other aspects of water treatment particularly the use of processes for organic precursor removal prior to disinfection. 3. Technology and Economics - The simplest and most economical conversion for many utilities, would be to the use of chloramines and the most difficult and expensive would be to the use of ozone. Conversion to chlorine dioxide would be intermediate in cost.

Chlorine↗
PubMed1996

Influence of tooth cryopreservation and storage time on microleakage.

OBJECTIVES: This study was conducted to compare microleakage of two new dentin bonding agents on freshly extracted teeth, cryopreserved teeth, or teeth stored in water containing 0.5% chloramine at 4 degrees C. METHODS: Rectangular Class V cavity preparations were made on the buccal and the lingual surface of wisdom teeth. They were filled with either Scotchbond Multi-Purpose and Z100 (3M Dental Products) or with Gluma 2000 and Pekafill (Bayer Dental). After thermocycling, silver staining penetration was evaluated under a light microscope. SEM examination and EDX analysis were performed to evaluate the microleakage pattern. The results were analyzed by the use of a two-way analysis of variance. RESULTS: Cryopreservation for 13 wk or 12 d refrigeration did not produce changes in the amount of microleakage. However, 48 d or longer of refrigeration increased microleakage. There was no correlation between changes in microleakage and storage time. Specimens prepared with both dentin bonding agents exhibited the same microleakage values and the same microleakage pattern. SIGNIFICANCE: Refrigeration at 4 degrees C in 0.5% chloramine for 48 d or longer may cause an increase in microleakage. Cryopreservation for 13 wk or short-term refrigeration did not affect the microleakage.

Analysis of Variance↗
PubMed2002

Approaches to radioiodination of insect neuropeptides.

High quality radioiodinated neuropeptides are essential to radioimmunoassays (RIA) and receptor binding assays. Approaches of direct and indirect labeling of neuropeptides with 125Iodine (125I) are compared. An HPLC equipped with an in-line gamma detector and UV absorbance detector was used to evaluate selected labeling methods and products. Treatment of [Y(1)]-adipokinetic hormone-I ([Y(1)]-AKH-I) with chloramine-T caused oxidative damage, whereas enzymatic labeling with lactoperoxidase in the presence of H(2)O(2) produced a good yield of intact, apparently monoiodinated peptide. Labeling of the FMRFamide-related peptide (YGGFMRFa), with chloramine-T apparently formed the methionine sulfoxide, which subsequently could be reduced with dithiothreitol. Products of high specific activity typically are achievable.

Animals↗
PubMed1990

Nicotine inhibits alpha-1-proteinase inhibitor inactivation by oxidants derived from human polymorphonuclear leukocytes.

Cigarette smoke can inactivate the alpha-1-proteinase inhibitor (alpha 1PI) by oxidative mechanisms and thus predisposes to the development of pulmonary emphysema. There are differences between the whole smoke and gas phase acting as alpha 1PI inactivators in vitro which suggests that the whole smoke is less oxidizing than the gas phase. Also studies on alpha 1PI oxidative inactivation in the lung of cigarette smokers gave controversial results. The reductive properties of cigarette tar which contains most of smoke nicotine may be some explanation of it. Therefore in this study we have investigated the effect of nicotine (0.4 mumol/l to 4 mmol/l) on the oxidative inactivation of human alpha 1PI by phorbol myristate acetate-activated polymorphonuclear leukocytes (PMNL), chloramine-T (15 mumol/l), hydrogen peroxide (15 mmol/l) and the superoxide radical (O2-.) generating system-xanthine (0.2 mmol/l)-xanthine oxidase (80 U/l). Nicotine at concentrations of greater than 40 mumol/l protected alpha 1PI from stimulated PMNL. The preincubation of PMNL with these concentrations of nicotine did not diminish their ability to inactivate alpha 1PI after stimulation. Nicotine (above 0.4 mumol/l) also protected alpha 1PI from chloramine-T but not from H2O2. The inhibition of O2-.-mediated alpha 1PI inactivation by nicotine was low and was observed only at a concentration of 4 mmol/l. This nicotine concentration did not affect xanthine oxidase activity. It is suggested that cigarettes with low nicotine contents can cause greater oxidative lung injury than their high nicotine counterparts and be a greater risk factor for the development of lung emphysema.

Humans↗
PubMed2003

Singlet oxygen (1O2)-oxidazable lipids in the HIV membrane, new targets for AIDS therapy?

Human immunodeficiency virus (HIV) is a lipid enveloped virus. The lipid envelope differs significantly from the lipid membrane of normal human cells: it contains high amounts of cholesterol, that is of importance for the virus-cell interaction (for entry and exit of the virus) at so-called lipid rafts. Cholesterol, as a R-C=C-R compound possesses an oxidazable carbenic bond. The present work suggests the inactivation of HIV by oxidation of viral cholesterol and/or unsaturated fatty acids. For oxidation, the relatively mild oxidant singlet oxygen (1O(2)) might be used. 1O(2) is generated by redoxcyclers (e.g., of the quinone type, such as vitamin K) or by chloramines (e.g., taurine-chloramine). At the 1O(2) concentrations necessary to inactivate lipid enveloped virus in human blood the oxidation-sensible critical hemostasis parameters such as thrombocytes and fibrinogen are only partly inactivated. Therefore, it is proposed to consider generators of 1O(2) as a new form of AIDS therapy.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Taurine: new implications for an old amino acid.

Taurine is a semi-essential amino acid and is not incorporated into proteins. In mammalian tissues, taurine is ubiquitous and is the most abundant free amino acid in the heart, retina, skeletal muscle, brain, and leukocytes. In fact, taurine reaches up to 50 mM concentration in leukocytes. Taurine has been shown to be tissue-protective in many models of oxidant-induced injury. One possibility is that taurine reacts with hypochlorous acid, produced by the myeloperoxidase pathway, to produce the more stable but less toxic taurine chloramine (Tau-Cl). However, data from several laboratories demonstrate that Tau-Cl is a powerful regulator of inflammation. Specifically, Tau-Cl has been shown to down-regulate the production of pro-inflammatory mediators in both rodent and human leukocytes. Taurolidine, a derivative of taurine, is commonly used in Europe as an adjunctive therapy for various infections as well as for tumor therapy. Recent molecular studies on the function of taurine provide evidence that taurine is a constituent of biologic macromolecules. Specifically, two novel taurine-containing modified uridines have been found in both human and bovine mitochondria. Studies investigating the mechanism of action of Tau-Cl have shown that it inhibits the activation of NF-kappaB, a potent signal transducer for inflammatory cytokines, by oxidation of IkappaB-alpha at Met45. Key enzymes for taurine biosynthesis have recently been cloned. Cysteine sulfinic acid decarboxylase, a rate-limiting enzyme for taurine biosynthesis, has been cloned and sequenced in the mouse, rat and human. Another key enzyme for cysteine metabolism, cysteine dioxygenase (CDO), has also been cloned from rat liver. CDO has a critical role in determining the flux of cysteine between cysteine catabolism/taurine synthesis and glutathione synthesis. Taurine transporter knockout mice show reduced taurine, reduced fertility, and loss of vision due to severe apoptotic retinal degeneration. Apoptosis induced by amino chloramines is a current and important finding since oxidants derived from leukocytes play a key role in killing pathogens. The fundamental importance of taurine in adaptive and acquired immunity will be unveiled using genetic manipulation.

Amino Acid Sequence↗
PubMed2001

Gas phase reactions of NH2Cl with anionic nucleophiles: nucleophilic substitution at neutral nitrogen.

Reactions of chloramine, NH2Cl, with HO-, RO- (R = CH3, CH3CH2, CH3CH2CH2, C6H5CH2, CF3CH2), F- , HS- , and Cl- have been studied in the gas phase using the selected ion flow tube technique. Nucleophilic substitution (S(N)2) at nitrogen to form Cl- has been observed for all the nucleophiles. The reactions are faster than the corresponding S(N)2 reactions of methyl chloride; the chloramine reactions take place at nearly every collision when the reaction is exothermic. The thermoneutral identity S(N)2 reaction of NH2Cl with Cl-, which occurs approximately once in every 100 collisions, is more than two orders of magnitude faster than the analogous reaction of CH3Cl. The significantly enhanced S(N)2 reactivity of NH2Cl is consistent with a previous theoretical prediction that the barrier height for the S(N)2 identity reaction at nitrogen is negative relative to the energy of the reactants, whereas this barrier height for reaction at carbon is positive. Competitive proton abstraction to form NHCl- has also been observed with more highly basic anions (HO-, CH3O-, and CH3CH2O-), and this is the major reaction channel for HO- and CH3O-. Acidity bracketing determines the heat of deprotonation of NH2Cl as 374.4 +/- 3.0 kcal mol(-1).

Journal Article↗
PubMed1978

Cholera: possible infection from aircraft effluent.

This paper presents the hypothesis that some cases of cholera might be due to effluent discharge from aircraft. The theoretical case is borne out by inspection of data on the physical conditions pertaining between high altitudes and ground level. A study of the distribution of isolated outbreaks and single cases of disease and their relation to major airline routes showed a reasonable correspondence. Sporadic outbreaks of cholera in Europe between 1970 and 1975 were found to lie within the flight paths of regular airline services from Calcutta, where cholera is endemic, to the Northern Hemisphere. Laboratory studies on the stability of Vibrio cholerae to conditions likely to be encountered in droplets falling from high altitude to the ground suggested that significant numbers of organisms might survive. It should be noted that in this study no account was taken of the effect of ultra-violet light on viability and it is known that at high altitides the ultraviolet light component of solar radiation is much higher than at ground level. Results of experiments where small numbers of organisms were inoculated into relatively poor media showed that rapid growth ensued and that sufficient organisms were produced to give an infective dose of Vibrio cholerae in 1-10 ml/fluid. It could be concluded that human infection could easily occur by ingestion of fluids such as milk or soup which had some time earlier received a fortuitous but slight contamination from the air. Investigation of one disinfectant (chloramine T) showed that it reacted rapidly and in a complex manner with peptone. One effect of this reaction was the elimination of bactericidal activity and it seems likely that, as at present employed, chloramine T is of doubtful value in aeroplane hygiene. One important conclusion that arises from this work is that if cholera can be spread, even only occasionally, by effluent from aircraft then close investigation should be made of the possibility of other bacteria and viruses being spread in a similar way.

Aircraft↗