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PubMed1979

Effects of environmental oxidant stressors on individuals with a G-6-PD deficiency with particular reference to an animal model.

Individuals with a G-6-PD deficiency have long been known to be at increased risk to experience acute hemolysis following exposure to elevated levels of certain oxidant drugs and industrial chemicals. However, the recognition of enhanced susceptibility to environmental (or ambient) pollutants has generally not been considered. Recent theoretical studies have suggested that elevated levels of ambient ozone may be an etiologic factor in the onset of acute hemolysis in the G-6-PD deficient individual. Furthermore, the proposed usage of either chloramines or chlorine dioxide as replacements for chlorine for the disinfection of drinking water should be investigated with respect to their potential adverse effects of individuals at increased risk to oxidant stressors. In order to test these theoretical associations, two mouse strains, one with low and the other with high levels of G-6-PD activity in their red blood cells are being investigated to determine if they simulate human G-6-PD deficient and normal individuals, respectively. Preliminary results indicate that the mouse strain with low G-6-PD activity is markedly more susceptible to sodium chlorite than mice of the high G-6-PD strain. This differential susceptibility to sodium chlorite toxicity between the high and low G-6-PD mouse strains suggests that further research designed to validate the efficacy of this mouse model as a predictor of the human situation is warranted.

Air Pollutants↗
PubMed1986

Products identified at an alternative disinfection pilot plant.

Many drinking water utilities have recently changed or are seriously considering changing their disinfection practice from chlorine to some alternative treatment process. However, most of these utilities are changing their disinfectants without evaluating chemical impacts. Therefore, a research cooperative agreement was developed with Jefferson Parish, LA, to evaluate four parallel streams treated with four different disinfectants (chlorine, monochloramine, chlorine dioxide, and ozone.) These streams, along with a fifth parallel stream, which was not treated with a disinfectant (control), were passed through both sand and granular activated carbon (GAC). Ozonation reduced the total organic carbon (TOC) and total organic halide (TOX) concentration by 0.3 mg/L and 10 micrograms/L, respectively. The average concentration of TOC for the other disinfectants was comparable to that associated with the nondisinfected stream (3.3 mg/L). The average instantaneous TOX concentration for chlorine dioxide, chloramine, and chlorine disinfection after 30 min contact time increased by 60, 92, and 238 micrograms/L, respectively, from a nondisinfected concentration of 25 micrograms/L. The volatile organics most affected by disinfection (chlorination) were the trihalomethanes. No significant change in concentration was noted after disinfection for the other volatile organics evaluated, such as 1,2-dichlorethane, dichloromethane, trichloroethylene, 1,1,2-trichloroethane, and carbon tetrachloride. Ozonation produced an average concentration reduction of 11 to 84% for most of the nonvolatiles evaluated. Conversely, a concentration increase of 43 to 100% was noted, after chlorination, for some of the nonvolatile organics.

Chloramines↗
PubMed2005

Radiolabeling of amyloid-beta peptides.

Nowadays, a wide variety of protocols for labeling proteins is available. However, radiolabeling remains one of the most powerful, sensitive and accurate methods to trace and quantitate proteins. Additionally, radiolabeling techniques are steadily gaining importance for diagnosis and treatment in nuclear medicine. There is a considerable number of radioisotopes, but only some are commonly used for basic biomedical research. Among them, the iodine radioisotopes (gamma-emitters) have several advantages for the labeling of proteins. This chapter focuses on radioiodination protocols for amyloidogenic peptides, using the Abeta peptides as a paradigm. The chloramine T, Iodo-Gen, and lactoperoxidase methods can be successfully applied to radioiodination of different amyloid peptides as long as free tyrosyl (or histidyl) groups are avail-able. However, these methods differ in their yield and the degree of oxidative damage conferred to labile peptides. When no tyrosines are available, the Bolton-Hunter methodology can be used. The labeling by the tyramine-cellobiose ligand trapping method is applicable to the study of cellular uptake and catabolism of amyloid peptides.

Amyloid beta-Peptides↗
PubMed1982

The effect of oxidation of the Met27 residue of [125I]monoiodoglucagon on receptor-binding affinity.

When glucagon is iodinated by the chloramine-T method, the Met27 residue is oxidized. This is not the case when the iodination is performed by the lactoperoxidase method. The two preparations can be purified to the same specific activity using QAE-Sephadex A-25 ion exchange chromatography. Receptor-binding studies in isolated rat adipocytes or hepatocytes revealed that the oxidized from possessed an average-binding affinity which is only about two thirds of that of the non-oxidized form. The reduced affinity of the oxidized tracer cannot be explained by an increased rate of dissociation.

Adipose Tissue↗
PubMed1989

Selective oxidation of methionine residues in Kunitz-type protease inhibitors.

Bovine pancreatic trypsin inhibitor (BPTI, also known as aprotinin or Kunitz inhibitor, a mini-protein composed of 58 amino-acid residues, containing a single methionine residue at position 52) has been selectively oxidized by treatment with chloramine T, under mild conditions, to the methionyl sulfoxide derivative. Spleen inhibitor II (SI II, an isoform of BPTI containing two methionine residues at positions 18 and 52) has been oxidized under the same conditions. Oxidation affects the functional properties of the two inhibitors differently: the antiproteolytic activity of BPTI towards bovine trypsin and chymotrypsin, porcine kallikrein and human leukocyte elastase is not changed upon oxidation, while in the oxidized SI II, the affinity for both chymotrypsin and elastase decreases, with respect to the native protein. These results have been directly related to the oxidation of Met18 in SI II, located at the P'3 site in the contact area with the proteases.

Amino Acid Sequence↗
PubMed1994

Determination of sulfated peptides by differential iodination.

A sequential approach was developed to label tyrosine sulfate and peptides containing tyrosine sulfate selectively. Amino acids and peptides containing tyrosine and tyrosine sulfate were first iodinated using chloramine-T-method. Reaction products were determined by RP-HPLC. Mono- and biiodination of tyrosine and several model peptides was achieved within 120 s incubation time. Iodination of free tyrosine sulfate and sulfated cholecystokinin26-33 was less than 5%. After desulfation of the reaction products with 1 N HCl successful radioiodination of desulfated tyrosine was carried out whereas tyrosine did incorporate radioactive iodine only 10%. As shown by RP-HPLC specific labeling of tyrosine sulfate containing peptides with 125iodine was achieved.

Amino Acid Sequence↗
PubMed1984

Radioimmunoassay for serum thyroglobulin designed for early detection of metastases and recurrencies in the follow-up of patients with differentiated thyroid carcinoma.

A radioimmunoassay (RIA) for the measurement of thyroglobulin in human serum was developed and factors that influence sensitivity were investigated. In a comparison of 3 different labeling procedures (chloramine T, iodogen, lactoperoxidase) iodogen-prepared tracer proved to be slightly superior with respect to sensitivity and stability. The shelf life of the tracer was improved by a protein-enriched buffer, which serves as a radical scavenger. The binding kinetics of tracer to antibody at different temperature ranges were examined, and the most rapid and complete binding was found at room temperature. For the preparation of standard curves, several artificial media were compared with thyroglobulin-free serum. Second antibody separation was investigated and optimized. By employing sequential saturation, sensitivity of 0.75 microgram/1 (B0-3 SD) and 50% intercept of less than 5 micrograms/l were achieved. The results of RIA measurements of thyroglobulin in 142 patients with papillary and follicular thyroid carcinoma after thyroidectomy and 131I treatment were compared with 131I whole-body scans. The results confirmed that serum thyroglobulin is an early indicator of recurrency.

Adenocarcinoma↗
PubMed2002

Mechanism of action of sodium hypochlorite.

The choice of an irrigating solution for use in infected root canals requires previous knowledge of the microorganisms responsible for the infectious process as well as the properties of different irrigating solutions. Complex internal anatomy, host defenses and microorganism virulence are important factors in the treatment of teeth with asymptomatic apical periodontitis. Irrigating solutions must have expressive antimicrobial action and tissue dissolution capacity. Sodium hypochlorite is the most used irrigating solution in endodontics, because its mechanism of action causes biosynthetic alterations in cellular metabolism and phospholipid destruction, formation of chloramines that interfere in cellular metabolism, oxidative action with irreversible enzymatic inactivation in bacteria, and lipid and fatty acid degradation. The aim of this work is to discuss the mechanism of action of sodium hypochlorite based on its antimicrobial and physico-chemical properties.

Bacteria↗
PubMed2004

Toxicity of model aliphatic amines and their chlorinated forms.

Aliphatic amines can be found in many wastewater effluents from industry, agriculture, pharmacy, and food processing. Amines can induce toxicological responses that are relevant in biochemical treatment processes, as well as in natural waters. This research compared the toxicity and inhibition caused by three aliphatic amines (n-propylamine, ethylmethylamine, and trimethylamine) and their chlorinated derivatives. The chemistry of chlorine interactions with these compounds was characterized by using membrane introduction mass spectrometry (MIMS). Acute toxicity assays were conducted by using a Microtox system with Phosphobacterium phosphoreum (also known as Vibrio fischeri) for the aliphatic amine compounds and their corresponding chlorinated derivatives, as identified by MIMS. Inhibition tests were conducted by using the oxygen utilization rate test with an enhanced nitrifier culture. The median effective concentration (EC50) values for chloropropylamine, chloroethylmethylamine, and chlorodimethylamine obtained by Microtox with a contact time of 15 min were 12.68, 19.72, and 15.92 microM, respectively. The EC50 values of these aliphatic chloramines from the Microtox test decreased by roughly one order of magnitude as a result of chlorination. Inhibition of nitrifiers also was observed in these amines. Trimethylamine and n-propylamine caused greater inhibition to nitrifiers than did ethylmethylamine under similar concentrations. Nitrifier inhibition from these amines increased after chlorination. The results of these tests indicated that aliphatic amines and their chlorinated derivatives could induce environmentally relevant toxicity responses in treatment settings and in receiving waters.

Amines↗
PubMed2005

Effect of disinfectants on microbial ecology in model distribution systems.

This research was conducted to assess the impact of various disinfectants on bacterial water quality within model distribution systems (i.e. annular reactors). After colonization with non-disinfected water, annular reactors were treated with relatively low doses of chlorine (0.4 mg/l), chlorine dioxide (0.15 mg/l), or chloramines (0.9 mg/l). Under the tested conditions, bacterial inactivation varied as a function of disinfectant type (ranking by efficiency per mg of oxidant: ClO2 > Cl2 > ClNH2) and sample type (bulk water vs. biofilm). Depending on the disinfectant, the log inactivation of suspended and attached bacteria were 0.7-1.2 and 0.5-1.0, respectively. The characterization of microbial communities in drinking water can be performed using biochemical and/or molecular methods. In this study, biochemical tests were used, showing that pseudomonad and pseudomonad-like bacteria, as in other studies, were the most predominant micro-organisms (e.g. Pseudomonas fluorescens, Brevundimonas vescularis). The ratio Gram-positive to Gram-negative organisms was 1 to 3. No drastic differences were observed between the non-treated and disinfected pipes. Based on the bacteriological data presented in these experiments, chlorine dioxide represents an alternative to chlorine for certain distribution systems.

Bacteria↗
PubMed1989

Elastase and papain inhibition by serum of mammals.

The protease-antiprotease imbalance concept has gained wide acceptance in reference to experimental animal models of human pulmonary emphysema. The destructive process may be induced by proteolytic enzymes such as porcine pancreas elastase (E) or papain (P), or by oxidants such as chloramine T (CT) which cause inactivation of alpha-1-antiprotease. The susceptibility to development of severe emphysema has been found to differ among animal species. We investigated the inhibition of elastase and papain by serum of seven species (rat, dog, human, rabbit, sheep, hamster, mini pig) and the effect of CT on serum inhibition. The relative inhibitor concentration of serum was expressed in terms of its inhibitor capacity for elastase and papain (EIC and PIC) defined as number of inhibited units (U) of enzyme catalysed hydrolysis of chromogenic peptide substrate (SAPNA and BAPNA) per unit of serum. The effect of CT on enzyme inhibition was quantified in terms of fractional loss of inhibition relative to control. The serum concentration of inhibitor was highest in the rat (EIC 8642 +/- 989 microU/microliter, PIC 214.2 +/- 110.3 microU/microliter; means +/- SD). Next in order of decreasing EICs were dog, human, rabbit, sheep, hamster, and mini pig exhibiting the lowest EIC (2523 +/- 184 microU/microliter) while sheep had lowest PIC (39.6 +/- 3.5 microU/microliter). The EIC/PIC ratio varied from 20 (mini pig) to about 100. The reduction of elastase inhibition after CT exposure of serum was high (80-100%) in rat, dog, human, and hamster, moderate (40%) in mini pig and rabbit, and low (10%) in sheep. Because papain was directly affected by CT the effect of CT on papain inhibition could not be analysed. The data suggest that the intrinsic antiprotease and antioxidant screen varies among experimental animals. For the purpose of animal models of emphysema, hamster appears to be most susceptible to the progressive destruction of lung parenchyma elicited by experimental burden of proteases or oxidants.

Animals↗
PubMed1991

Radio-iodinated and internally labelled (35S) IgM monoclonal antibodies in a syngenic rat model.

To simulate the human situation concerning human monoclonal antibodies (MAbs), we have introduced a new syngenic rat model with an implanted rat colon carcinoma. Rat IgM MAbs (10B12), labelled by the chloramine-T method with 125I or internally with 35S, were injected intravenously into the rats and the biodistribution was studied for 8 days. The radioactivity uptake in the tumours of the 35S label was higher than that of the 125I label and the retention of 35S in the tumours gave tumour/blood ratios 8 times higher than those of 125I at 48 and 96 h after injection. In this model we have shown that dehalogenation of iodinated IgM MAbs is a serious problem. We therefore suggest that internally labelled MAbs should be used and that further investigations should be carried out in a syngenic rat model, since this probably reflects the clinical situation better than the nude mouse model.

Animals↗
PubMed1991

Biologically active monoiodinated alpha-MSH derivatives for receptor binding studies using human melanoma cells.

Three different monoiodinated radioligands of alpha-MSH (alpha-melanocyte-stimulating hormone) were compared in a binding assay with human D10 melanoma cells: [Tyr(125I)2]-alpha-MSH, [Tyr(125I)2,NIe4]-alpha-MSH, and [Tyr(125I)2,NIe4,D-Phe7]-alpha-MSH. They were prepared either by the classical chloramine T method or by the Enzymobead method. A simple and rapid purification scheme was developed consisting of a primary separation on reversed-phase C18 silica cartridges immediately after the iodination, followed by HPLC purification before each binding experiment. Biological testing of the three radioligands showed that they all retained high melanotropic activity in the B16 melanin assay and the Anolis melanophore assay. However, in human D10 melanoma cells, [Tyr(125I)2,NIe4]-alpha-MSH led to a high degree of non-specific binding to the cells which could not be displaced by excess alpha-MSH and only partially by [NIe4]-alpha-MSH. The [Tyr(125I)2,NIe4,D-Phe7]-alpha-MSH tracer gave similar results but with a much lower proportion of non-specific binding. On the other hand, [Tyr(125I)2]-alpha-MSH proved to be an excellent radioligand whose non-specific binding to the D10 cells was not higher than 20% of the total binding.

Biological Assay↗
PubMed2005

Treatment of ichthyophthiriasis after malachite green. I. Concrete tanks at salmonid farms.

Since the use of malachite green was banned in many European countries, new alternative treatments have been tested to prevent white spot disease caused by Ichthyophthirius multifiliis. We tested formalin, potassium permanganate (KMnO4), chloramine-T, hydrogen peroxide (H2O2) and Per Aqua or Desirox alone or in combinations of 2 chemicals, one of which was always formalin, in 50 m2 concrete tanks at 2 farms producing salmon Salmo salar smolt in 2001 and 2002. Both Per Aqua and Desirox are combinations of peracetic acid, acetic acid and hydrogen peroxide. The alternative chemicals or their combinations can be used successfully to lower the parasite burden to such a level that no high mortality occurs during the first 4 wk after the start of an infection. This period of time allows the fish to develop immunity against these ciliates, and treatments can be reduced and stopped in due course. I. multifiliis decreased in number 3 to 4 wk after the beginning of the infection in all the treatments. Large differences in parasite burden and mortality occurred among the replicates in all except the Desirox-formalin tanks, which means that they are not as reliable as the malachite green-formalin used previously. It was also evident that the chemicals and their concentrations must be planned carefully to suit the conditions on each farm.

Acetic Acid↗
PubMed2005

Treatment of ichthyophthiriasis after malachite green. II. Earth ponds at salmonid farms.

We tested formalin, chloramine-T-formalin and Desirox-formalin, for use against white spot disease (ichthyophthiriasis) caused by Ichthyophthirius multifiliis at 3 salmonid farms (Salmo salar and S. trutta smolt reared in earth ponds). I. multifiliis disappeared from most individuals 4 to 5 wk after the first treatment (and after the first I. multifiliis were found) with all chemicals, indicating that combinations of these chemicals, and even formalin alone, can be used to lower the parasite burden in earth ponds to such a level that no mortality occurs. This was the case when the fish were treated frequently at the beginning of the infection. Treatment can be stopped once the fish have achieved immunity to ichthyophthiriasis. The developing immunity was also revealed by the distribution of ciliates in the course of the disease. At the beginning of the infection I. multifiliis individuals were randomly distributed among the fish, but after 2 to 3 wk, when all the fish were infected, ciliates had increased in numbers and were aggregated in such a way that some fish carried quite heavy burdens. However, over 60% of the fish were free of the parasites after 4 to 5 wk, and had few or no ciliates, meaning that the distribution was even more aggregated. Sea trout had fewer parasites than salmon, and they also recovered from infection earlier even though the treatments and ponds were similar, indicating variation in resistance to I. multifiliis between fish species. It was also evident that the chemicals and their concentrations must be planned carefully to suit the conditions at each farm.

Animals↗
PubMed2006

Luminal oxidants selectively modulate electrogenic ion transport in rat colon.

AIM: To investigate the effects of luminal exposure to H2O(2) and two related thiol oxidizing agents on basal and stimulated chloride secretion in native colon using electrophysiological and pharmacological approaches. METHODS: Unstripped rat distal colon segments were mounted in Ussing chambers. Potential difference, calculated resistance and short-circuit current across unstripped colon segments were monitored with a dual voltage/current clamp. Paracellular permeability was assessed by measuring the mucosa-to-serosa flux of a fluorescent probe (FITC). RESULTS: Luminal exposure to hydrogen peroxide transitorily stimulated chloride secretion without altering barrier function. This stimulatory effect could be blocked by basolateral atropine but not indomethacin. The cysteine and methionine oxidizing compounds, phenylarsine oxide and chloramine T respectively, mimicked the effect of H2O(2), except for a drop in transcolonic resistance after 30 min. In contrast to the observed stimulatory effect on basal secretion, cAMP-stimulated electrogenic ion transport was blunted by luminal H2O(2). However, the Ca(2+)-activated response remained unchanged. CONCLUSION: H2O(2) may be an important selective modulator of intestinal ion and water secretion in certain pathologic conditions such as inflammation or ischemia-reperfusion by multiple mechanisms.

Animals↗
PubMed2002

Purification and characterization of beta-N-acetylhexosaminidase from rice seeds.

N-Acetyl-beta-D-hexosaminidase (beta-HexNAc'ase) (EC 3.2.1.52) was purified from rice seeds (Oryza sativa L. var. Dongjin) using ammonium sulfate (80%) precipitation, Sephadex G-150, CM-Sephadex, and DEAE-Sephadex chromatography, sequentially. The activities were separated into 7 fractions (Fsub1;- F7sub7) by CM-Sephadex chromatography. Among them, F6 was further purified to homogeneity with a 13.0% yield and 123.3 purification-fold. The molecular mass was estimated to be about 52 kDa on SDS-PAGE and 37.4 kDa on Sephacryl S- 300 gel filtration. The enzyme catalyzed the hydrolysis of both p-nitrophenyl-N-acetyl-beta-D-glucosaminide (pNP-GlcNAc) and p-nitrophenyl-N-acetyl-beta-D-galactosaminide (pNPGalNAc) as substrates, which are typical properties of beta-HexNAc'ase. The ratio of the pNP-GlcNAc'ase activity to the pNP-GalNAc'ase activity was 4.0. However, it could not hydrolyze chitin, chitosan, pNP-beta-glucopyranoside, or pNP-beta-galactopyranoside. The enzyme showed K(M), V(max) and K(cat) for pNP-GlcNAc of 1.65mM, 79.49mM min(1), and 4.79 x 10(6) min(1), respectively. The comparison of kinetic values for pNPGlcNAc and pNP-GalNAc revealed that the two enzyme activities are associated with a single binding site. The purified enzyme exhibited optimum pH and temperature for pNPGlcNAc of 5.0 and 50 degrees C, respectively. The enzyme activity for pNP-GlcNAc was stable at pH 5.0-5.5 and 20-40 degrees C. The enzyme activity was completely inhibited at a concentration of 0.1 mM HgCl(2) and AgNO(3), suggesting that the intact thiol group is essential for activity. Chloramine T completely inhibited the activity, indicating the possible involvement of methionines in the mechanism of the enzyme.

Acetylgalactosamine↗
PubMed1976

[Disinfection of sewage waters from rendering plants with peracetic acid].

In our experiments, peracetic acid--known in commerce as "Wolfasteril" was tested as a new and efficient disinfectant to disinfect sewage waters from rendering plants. Peracetic acid was used in experiments in concentration of 0.1 to 1.0% for 30 sec. to 60 min. As a comparative agent, 5% chloramine was used. Results obtained in preliminary and main experiments proved that peracetic acid is fully appropriate to disinfect biologically cleaned sewage waters in rendering plants. Sewage waters supplying the main stream has to pass mostly a short section after having left the water clarifier. Consequently, the concentration of 1% peracetic acid acting for 30 sec. is the optimum one. The recommendation of this application norm for peracetic acid in water clarifiers from rendering plants being at least suitable in controlling disasters.

Acetates↗