Effect of enhanced bromide intake on the concentration ratio I/Br in the rat thyroid gland

Biological Trace Element Research - Interaction of bromine with iodine was studied in the rat thyroid gland under the conditions of different bromide intake. Bromine and iodine in the thyroid dry...     

Effect of increased bromide intake on iodine excretion in rats

The time course of iodine excretion in adult male rats substantially differs from bromine excretion. Bromine is excreted at a single rate, whereas iodine evinces two excretion rates. Even a strong increase in bromide intake in experimental animals failed to affect the rate of iodine excretion but it lowered the fraction of iodine accumulated increase in bromide intake in experimental animals failed to affect the rate of iodine excretion but it lowered the fraction of iodine accumulated in the thyroid gland by 20% probably by affecting the transport of iodide into the thyroid gland.     

Comparison of Chlorine, Bromine, and Iodine as Disinfectants for Swimming Pool Water

Studies on the germicidal activity of chlorine, bromine, and iodine were made by use of the Association of Official Agricultural Chemists official first action method for determining effectiveness of swimming pool water disinfectants. In this procedure, 0.3 ppm of available chlorine as chlorine gas has activity equivalent to 0.6 ppm of available chlorine in the buffered sodium hypochlorite control when Escherichia coli is used as the test organism. With Streptococcus faecalis as the test organism, 0.45 ppm of available chlorine as gaseous chlorine gives activity equivalent to the control. Liquid bromine at 1.0 ppm is as effective as the 0.6 ppm of available chlorine hypochlorite control with E. coli as the test organism, but 2.0 ppm of liquid bromine is necessary to provide activity equivalent to the 0.6 ppm of available chlorine control when S. faecalis is employed. With iodine as metallic iodine, 2.0 ppm is necessary to provide a result equivalent to the 0.6 ppm of available chlorine control with both E. coli and S. faecalis. In the various systems tested, gaseous chlorine was the most active form of available chlorine; liquid bromine provided the most active form of bromine, and metallic iodine provided the most active form of iodine.     

Monohalogenated maleimides as potential agents for the inhibition of Pseudomonas aeruginosa biofilm

New monohalogenated maleimide derivatives (with bromine, chlorine or iodine) were synthesized to test the effect of halogen atoms in inhibiting the formation of Pseudomonas aeruginosa biofilm. The evaluation of their biological activities clearly defines a structure–activity relationship. In this study, the bactericidal action of the three compounds was observed at the concentration range 0.3–5.0 mM on Luria-Bertani agar plates. The halogen atom of these molecules was critical in modulating the antibacterial activity, with a slightly higher effectiveness for chlorine. Confocal laser scanning microscopy was used to examine P. aeruginosa biofilms cultivated in flow cells. At concentration as low as 40 μM, the bromine and iodine compounds displayed a total inhibition towards the formation of bacterial biofilm. At this concentration, the bacterial attachment to glass surfaces was strongly affected by the presence of bromine and iodine whereas the chlorine derivative behaved as a bactericidal compound. A bioluminescent reporter strain was then used to detect the effect of the chemically synthesized maleimides on quorum sensing (QS) in P. aeruginosa. At the concentration range 10–100 μM, bioluminescence assays reveal that halogenated maleimides were able to interfere with the QS of the bacterium. Although the relationship between the weak inhibition of cell-to-cell communication (15–55% of the signal) and the high inhibition of biofilm formation has not been elucidated clearly, the results demonstrate that bromo- and iodo-N-substituted maleimides bromine and iodine may be used as new potent inhibitors that control bacterial biofilms.     

Effect of high bromide levels in the organism on the biological half-life of iodine in the rat

In experiments on rats, a significant influence of an extraordinarily high bromide intake on the whole-body biological half-life of iodine was established. Very high bromide intake (1) decreased the amount of radioiodide accumulated in the thyroid, (2) changed the proportion between the amount of iodine retained in the thyroid and the total amount of absorbed iodine, (3) significantly shortened the biological half-life of iodine in the thyroid from approximately 101 h to 33 h in animals maintained on an iodine-sufficient diet and from 92 h to about 30 h in rats fed a low-iodine diet, and (4) changed the time-course (added a further phase) of iodine elimination from the body. These changes were caused, with high probability, by an increase of iodine elimination by kidneys due to an excess of bromide. The overall picture of iodine elimination in animals fed the low-iodine diet was similar to that in animals maintained on iodine-sufficient diet. Presented in part at the 20th Workshop on Macro and Trace Elements held in Jena (Germany) on December 1–2, 2000.     

Metabolism of bromide and its interference with the metabolism of iodine

The present knowledge about the metabolism of bromide with respect to its goitrogenic effects, including some conclusions drawn from our recent research on this subject, is reviewed. Firstly, the biological behavior of bromide ion is compared with that of chloride and iodide. Secondly, the details about distribution and kinetics of bromide ions in the body and in 15 different organs and tissues of the rat are given. Significant correlation between the values of the steady-state concentration of bromide in the respective tissue and of the corresponding biological half-life was found in most tissues examined. A remarkably high concentration of radiobromide was found in the skin, which represents, due to its large mass, the most abundant depot of bromide in the body of the rat. Thirdly, the effects of excessive bromide on the rat thyroid are summarized, along with the interference of exogenous bromide with the whole-body metabolism of iodine. It is suggested that high levels of bromide in the organism of experimental animals can influence their iodine metabolism in two parallel ways: by a decrease in iodide accumulation in the thyroid and skin (and in the mammary glands in lactating dams), and by a rise in iodide excretion by kidneys. By accelerating the renal excretion of iodide, excessive bromide can also influence the pool of exchangeable iodide in the thyroid. Finally, our recent results concerning the influence of high bromide intake in the lactating rat dam on iodine and bromide transfer to the suckling, and the impact of seriously decreased iodine content and increased bromide concentration in mother's milk on the young are discussed. We must state, however, that the virtue of the toxic effects of excessive bromide on the thyroid gland and its interference with the biosynthesis of thyroid hormones, as well as the exact mechanism of bromide interference with postnatal developmental processes remains to be elucidated.     

Killing of Chlorine-Resistant Bacteria by Chlorine-Bromine Solutions

The disinfective power of chlorine, bromine, and mixtures of chlorine and bromine at different ratios was compared. The influence of pH was also studied. The experiments were carried out in “purified” water and in natural waters of swimming pools, river, and sea. In the presence of high amounts of nitrogenous growth-promoting material (at neutral pH), bromine was more effective than chlorine; in waters containing low amounts of nitrogenous growth-promoting material, chlorine was found superior. Mixtures of chlorine and bromine at various ratios were found to increase in effectiveness inversely to the percentage of hypobromite generated, down to 10 or 5%. Such effectiveness was found at pH levels of 5.4 to 8.6 in both purified and natural water containing high and low amounts of nitrogenous growth-promoting material. Therefore, the above mixtures seem of practical value for the disinfection of various natural waters. Escherichia coli isolated in the presence of chlorine, either from swimming pools or after deliberate exposure to the halogen, were shown to be chlorine-resistant mutants. Their resistance was maintained for at least nine passages in the absence of the disinfectant, which accounts for the number of passages tested. Chlorine-resistant mutants were not affected by bromine alone but did show a marked sensitivity to low concentrations of bromine active in the presence of chlorine. This was achieved by admixing small amounts of bromide to hypochlorite. A hypothetical model is presented to explain the synergistic sequential block by the two disinfectants. Some chlorine-resistant mutants were found to have changed into relatively slow-growing organisms with a changed phase-sensitivity pattern.     

Effect of long-term administration of arsenic (III) and bromine with and without selenium and iodine supplementation on the element level in the thyroid of rat

The aim of this study was to evaluate the influence of arsenic and bromine exposure with or without iodine and selenium supplementation on the element level in the thyroid of rats. Four major groups of Wistar female rats were fed with respective diets: group A - standard diet, group B - iodine rich diet (10 mg I/kg food), group C - selenium rich diet (1 mg Se/kg) and group D - iodine and selenium rich diet (as in group B and C). Each group was divided into four subgroups per 7 animals each receiving either NaAsO(2) ip (6.5 mg.kg(-1) twice a week for two weeks and 3.25 mg.kg(-1) for six weeks) or KBr in drinking water (58.8 mg.l(-1)) for 8 weeks or combined administration of both substances. Remaining subgroup served as controls. After 8 weeks thyroid glands were analyzed by ICP-MS for As, Br, Se, and I content. The exposition of rat to arsenic or bromine causes the accumulation of these elements in the thyroid gland ( approximately 18 ppm of As, approximately 90 ppm of Br) and significantly affects iodine and selenium concentration in the thyroid. In iodine and/or selenium supplemented rats the bromine intake into the thyroid was lowered to approximately 50% of the level in unsupplemented animals. Also selenium thyroid level elevated due to KBr administration was lowered by iodine supplementation in the diet. The accumulation of arsenic in the thyroid was not influenced by selenium or iodine supplementation; however, As(III) administration increased iodine thyroid level and suppressed selenium thyroid level in selenium or iodine supplemented group of animals.     

Interaction between thyroid hormones and erythrocyte membranes: competitive inhibition of binding 131 I-L-triiodothyronine and 131 I-L-thyroxine by their analogs.

Molecular structural characteristics of thyroid hormones which influence binding to the erythrocyte membranes were investigated by competitive binding experiments. The ability of thyroid hormone analogs to displace 131 I-L-thyroxine and 131 I-L-triiodothyronine from the membranes was considered evidence of their competitive binding. The diphenyl ether linkage (thyronine) was essential as compounds with a single aromatic ring were weakly competitive. The presence of three iodine atoms at 3, 5 and 3' positions on thyronine was optimal for maximal competitive binding. There was weak competitive binding of analogs if chlorine or bromine was substituted for iodine. The alanine side chain was required for optimal binding as N-acetyl-l-thyroxine and various deaminated analogs were poor competitors compared to T4 and T3. L-isomers of T4 and T3 showed greater competitive binding to erythrocyte membranes than the corresponding d-isomers.     

Halogen bonding at the ATP binding site of protein kinases: Preferred geometry and topology of ligand binding

Halogenated ligands have been widely developed as potent, and frequently selective, inhibitors of protein kinases (PK). Herein, all structures of protein kinases complexed with a halogenated ligand, identified in the PDB, were analyzed in the context of eventual contribution of halogen bonding to protein–ligand interactions. Global inspection shows that two carbonyl groups of residues located in the hinge region are the most abundant halogen bond acceptors. In contrast to solution data, well-defined water molecules, located at sites conserved across most PK structures, are also involved in halogen bonding. Analysis of cumulative distributions of halogen–acceptor distances shows that structures displaying short contacts involving a halogen atom are overpopulated, contributing together to clearly defined maxima of 2.82, 2.91 and 2.94 Å for chlorine, bromine and iodine, respectively. The angular preference of a halogen bond favors ideal topology (180°, 120°) for iodine. For bromine the distribution is much more dispersed, and no such preference was found for chlorine. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases (2012).     

Bromide kinetics and distribution in the rat. I

Biological half-lives of bromine in 15 different organs and tissues of the rat, in addition to the whole-body half-life, were determined by measuring the radioactive concentration of 82Br-bromide in samples of tissues collected at the time intervals of 12-396 h from animals that continuously (up to 17 d) received 82Br-labeled bromide in their drinking water. The half-life values, calculated from the experimental data by the method of gradual estimates of the parameters in question with the SPSS statistical program, ranged from 94.3+/-14.6 h in the thyroid gland to 235.0+/-88.9 h in liver. In most of the studied tissues, the biological half-lives of bromine were shorter than in the whole body, in which it equaled 197.8+/-22.2 h. Significant correlation between the values of the steady-state concentration of bromide and of the biological half-life was found for most tissues (except for liver). The steady-state concentrations of 82Br in tissues are probably proportional to the magnitude of bromide space, and, consequently, of chloride space.     

4种常用水产药物对青虾幼虾的毒性研究

采用静水法研究了4种常用水产药物对青虾幼虾的毒性。结果表明：水温29℃~30℃时,溴氯海因对青虾幼虾24 h、48 h和72 h的LC50分别为19.05 mg/L、11.75 mg/L、11.75 mg/L,安全浓度为1.24 mg/L;聚维酮碘对青虾幼虾的24 h、48 h和72 h的LC50分别为49.27 mg/L、44.61 mg/L、43.68 mg/L,安全浓度为10.52 mg/L;甲醛对青虾幼虾的24 h、48 h和72 h的LC50分别为72.47 mg/L、66.41 mg/L、53.71 mg/L,安全浓度为10.93 mg/L;高锰酸钾对青虾幼虾的24 h、48 h和72 h的半致死浓度（LC50）分别为6.06 mg/L、4.07 mg/L、3.79 mg/L,安全浓度为0.48 mg/L。4种药物对青虾幼虾的毒性依次为高锰酸钾〉溴氯海因〉聚维酮碘〉甲醛。     

Comparative in vitro activity of chlorine and bromine on the cysts of free-living amoebae

A continuous flow type apparatus is used for investigation of the chlorine and bromide activity in vitro on the cysts of two free-living amoeba strains : Naegleria gruberi and Acanthamoeba polyphaga. The Naegleria cysts are sensitive more to chlorine than to bromine ; those of Acanthamoeba are perfectly resistant to these disinfectants in the limit of the available concentrations in swimming-pools. The sensibility to these disinfectants stays the same at 25 degrees C and 35 degrees C.     

Role of bromine in the formation of the refractile inclusions of the vesicle cells of the Bonnemaisoniaceae (Rhodophyta)

Summary Refractile inclusions characteristic of the vesicle cells of members of the Bonnemaisoniaceae fail to form if bromide is omitted from the culture medium. Electron microprobe analysis shows the localization of bromine in these cells. When grown in the presence of bromide, but not when grown in its absence, these organisms oxidize iodide to iodine; in Trailliella, this oxidation occurs at the vesicle cells.     

High bromide intake affects the accumulation of iodide in the rat thyroid and skin

The effect of a high bromide intake on the kinetics of iodide uptake and elimination in the thyroid and skin of adult male rats was studied. In rats fed a diet with sufficient iodine supply (>25 μg I/d), the iodide accumulation in the skin predominated during the first hours after ¹³¹I -iodide application. From this organ, radioiodide was gradually transferred into the thyroid. A high bromide intake (>150 mg Br⁻/d) in these animals led to a marked decrease in iodide accumulation, especially by the thyroid, because of an increase in iodide elimination both from the thyroid and from the skin. In rats kept under the conditions of iodine deficiency (<1 μ I/d), the iodide accumulation in the thyroid, but not in the skin, was markedly increased as a result of a thyrotropic stimulation. The effect of a high bromide intake (>100 mg Br⁻/d) in these animals was particularly pronounced because the rates of iodide elimination were most accelerated both from their thyroid and from their skin. Presented in part at the 20th Workshop on Macro and Trace Elements held in Jena (Germany) on December 1–2, 2000.     

HALOGENATION IN THE RHODOPHYTA1,2 A REVIEW

The halogens—chlorine, bromine and iodine—play an important, role in the biochemical processes of marine red algae. Recent studies show that various species from at least 5 orders of the Rhodophyta possess the unique ability to synthesize organic halogen-containing compounds which are derived from seawater components. A variety of substances have been reported, with various structures from simple aliphatic halo-ketones and brominated phenols to more sophisticated mono-, sesqui- and diterpenes. While the biological functions of these compounds are not clearly understood, they appear to provide environmental advantage, probably involving predator avoidance responses and microflora antibiosis.     

Isolation of the Bromo Analogue of Caldariomycin from Caldariomyces fumago

When bromide ion was substituted for chloride in the growth medium of Caldariomyces fumago, a new substance was produced. It was isolated by solvent extraction and purified by alumina chromatography. Examination of the physicochemical properties of the substance led to its identification as the bromo analogue of the normal metabolite, caldariomycin. Thus, biological substitution of bromine for chlorine has been demonstrated in the metabolic formation of a purely aliphatic secondary mold metabolite.     

Determination of bromine and iodine in normal tissues from Beijing healthy adults

The contents of bromine and iodine in samples of heart, liver, spleen, lung, muscle, and hair from healthy adults living in Beijing, China, were determined using epithermal neutron activation analysis. The results indicate that the contents of bromine in lung and iodine in liver are higher than those in other tissues, except human hair. The bromine contents in Beijing human tissues are significantly lower than those in other countries. The contents of iodine are slightly lower than those in other countries, but the difference is not significant. Three biological standard reference materials were simultaneously determined with the samples, and our results agree well with the certified values.     

N-haloacetylimino neonicotinoids: potency and molecular recognition at the insect nicotinic receptor

This structure-activity relationship study for neonicotinoids with an N-haloacetylimino pharmacophore identifies several candidate compounds showing outstanding insecticidal potency and consequently leads to establishing their molecular recognition at an insect nicotinic receptor structural model, wherein the neonicotinoid halogen atoms (fluorine, chlorine, bromine, and iodine) variously interact with the receptor loops C-D interfacial niche via H-bonding and/or hydrophobic interactions.     

Development of thyroid dysfunction among women with excessive iodine intake – A 3-year follow-up

ObjectivesThyroid dysfunction can be a result of excessive iodine intake, which may have adverse health consequences, particularly for women in fertile age. In 2010, we conducted a cross-sectional study among lactating women with excessive iodine intake in the Saharawi refugee camps in Algeria and found a high prevalence of thyroid dysfunction. Three years later, we conducted a follow-up study to monitor the iodine situation and explore whether thyroid dysfunction still was highly prevalent when the women no longer were post-partum. None of the women were treated for hyper- or hypothyroidism between baseline and follow-up.MethodsIn 2013, we were able to recapture 78 of the 111 women from the baseline. Thyroid hormones and antibodies were measured in serum and thyroid size was assessed by palpation. Urinary iodine concentration (UIC) and drinking water iodine concentration were measured.ResultsThe overall prevalence of thyroid dysfunction and/or positive antibodies was 34.3% and was not significantly changed from baseline. Of the non-pregnant women we reexamined, 17 had hypo- or hyperthyroidism in 2010; among these, 12 women still had abnormal thyroid function at follow-up. In addition, we found 9 new cases with marginally abnormal thyroid function. Women with thyroid dysfunction and/or positive antibodies had significantly higher BMI and thyroglobulin than women with normal thyroid function. We also found that women with high breast milk iodine concentration (BMIC) at baseline had more thyroid dysfunction at follow-up than the women with lower BMIC at baseline.ConclusionsAt follow-up, the prevalence of thyroid dysfunction was still high and had not changed during the 3 years between studies and from a postpartum period. The women still had a high iodine intake indicated by high UIC. Breast milk iodine concentration from baseline predicted thyroid dysfunction at follow-up.