|
|
The Iodine Group | |
|
Home | Orthoiodosupplementation | Body | Disease | Special | Overviews |
||
|
|
VAN LEEUWEN, LOEBER, SANGSTER
The effect of sodium bromide on thyroid function.van Leeuwen, FXR; Hanemaaijer, R; Loeber, JG Archives of Toxicology. 1988. [abstract only]
"The thyroid-toxic properties of bromide ion were first observed more than a decade ago. Although bromide ion is widely distributed in nature, forming a natural constituent of soil, plants, and animals, the main route of exposure of man stems from bromide residues present in food commodities as a result of the abundant use of bromide-containing pesticides, like methylbromide and ethylene dibromide, for soil fumigation in intensive horticulture and for postharvest treatment. Additional exposure may arise from the use of bromide-containing medicines. Although the prescribed use of these drugs is obsolete, in many countries over-the-counter sedatives still contain bromide. The above-mentioned exposure of man to bromide was the reason for the interest of toxicologists in this ion. "
Skin lesions due to exposure to methyl bromide.Hezemans-Boer M, Toonstra J, Meulenbelt J, Zwaveling JH, Sangster B, van Vloten WA. Arch Dermatol. 1988 Jun;124(6):917-21. [abstract only]
"Six patients were occupationally exposed to high concentrations of methyl bromide during a fumigation procedure using adequate airway protection. Within a few hours all patients developed skin lesions, consisting of sharply demarcated erythema with multiple vesicles and large bullae. There was a striking predisposition for parts of the skin that were relatively moist or subject to mechanical pressure, such as axillae, groin, and abdomen. Microscopically, early skin lesions revealed necrosis of keratinocytes, severe edema of the upper dermis, subepidermal blistering, and diffuse infiltration of neutrophils and, to a lesser degree, eosinophils. Two patients developed an urticarial rash approximately one week after the exposure. On histologic examination, these late lesions showed combined features of a spongiotic dermatitis and urticaria. No immunopathologic manifestations were observed. In all patients, the skin returned to normal after four weeks, except for some residual hyperpigmentation. Plasma bromide levels after exposure strongly suggested percutaneous absorption of methyl bromide."
The toxicology of bromide ion.van Leeuwen FX, Sangster B. Crit Rev Toxicol. 1987;18(3):189-213. Review. [abstract only]
"Inorganic bromide is widely distributed in nature. Its natural physiological role in animal life is unknown. More than a century ago bromide was introduced in medicine as an antiepileptic drug. Nowadays, man is primarily exposed to bromide via food as the result of use of bromide-containing fumigants in intensive horticulture and in the treatment of food stocks. In this review exposure of man to bromide is described, and the pharmacological and toxicological effects of bromide ion are discussed."
The influence of sodium bromide in man: a study in human volunteers with special emphasis on the endocrine and the central nervous system.Sangster B, Blom JL, Sekhuis VM, Loeber JG, Rauws AG, Koedam JC, Krajnc EI, van Logten MJ. Food Chem Toxicol. 1983 Aug;21(4):409-19. [abstract only]
"Sodium bromide was administered orally in capsules to healthy volunteers in doses of 0, 4 or 9 mg Br-/kg/day using a double-blind design. Each treatment was given to seven males for 12 weeks and to seven non-pregnant females (not using oral contraceptives) over three full cycles. Special attention was paid to possible effects on the endocrine and central nervous systems. At the start and end of the study, a full medical history, the results of a physical examination, haematological studies and standard clinical chemistry and urine analyses were recorded for each subject. These showed no changes for individuals following treatment, except for some incidence of nausea associated with bromide-capsule ingestion. Mean plasma-bromide concentrations at the end of treatment were 0.08, 2.14 and 4.30 mmol/litre for males and 0.07, 3.05 and 4.93 mmol/litre for females of the 0-, 4- and 9-mg Br-/kg/day groups, respectively. Plasma half-life was about 10 days. In the females taking 9 mg Br-/kg/day (but in no other group) there was a significant (P less than 0.01) increase in serum thyroxine and triiodothyronine between the start and end of the study but all concentrations remained within normal limits. No changes were observed in serum concentrations of free thyroxine, thyroxine-binding globulin, cortisol, oestradiol, progesterone or testosterone, or of thyrotropin, prolactin, luteinizing hormone (LH) and follicle-stimulating hormone before or after the administration of thyrotropin-releasing hormone and LH-releasing hormone. Analysis of neurophysiological data (EEG and visual evoked response) showed a decrease in delta 1- and delta 2-activities and increases in beta-activities and in mean frequency (Mobility parameter) in the groups on 9 mg Br-/kg/day, but all the findings were within normal limits."
Effect of sodium bromide on endocrine parameters in the rat as studied by immunocytochemistry and radioimmunoassay.Loeber JG, Franken MA, van Leeuwen FX. Food Chem Toxicol. 1983 Aug;21(4):391-404. [abstract only]
"Male rats were fed a normal or sodium bromide-enriched diet for 4 or 12 weeks. Sodium bromide concentrations were 0, 20, 75, 300, 1200 and 19,200 mg/kg diet. At the end of the experiments the pituitary gland, thyroid and testes were examined by histopathological and immunocytochemical techniques, while serum hormone levels were established by radioimmunoassay. Histopathological examination revealed an activation of the thyroid and a decreased spermatogenesis in the testes in the highest dose group. Using immunocytochemical techniques a decrease was noted in the amount of thyroxine in the thyroid. No effect was found in growth hormone-producing cells in the pituitary gland, while immunoreactivity for thyroid-stimulating hormone and for adrenocorticotropic hormone was increased. The concentration of thyroxine, testosterone and corticosterone in the serum appeared to be decreased. Due to feedback regulation, the pituitary gland was stimulated to produce and release thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotropic hormone and insulin, whereas the release of growth hormone was suppressed. Most of these changes were restricted to rats on the highest treatment level. It is concluded that sodium bromide, at least in high doses, directly disturbs the function of the thyroid, testes and adrenals."
Toxicity of sodium bromide in rats: effects on endocrine system and reproduction.van Leeuwen FX, den Tonkelaar EM, van Logten MJ. Food Chem Toxicol. 1983 Aug;21(4):383-9. [abstract only]
"Bromide has a low acute oral toxicity, with LD50 values in rodents ranging from 3500 to 7000 mg/kg body weight. It is rapidly absorbed and steady-state serum levels have been reached in rats within 4 weeks. The biological half-life of bromide, and consequently the serum levels, are strongly dependent on chloride intake. Feeding of sodium bromide to rats for 90 days in concentrations of 0, 75, 300, 1200, 4800 and 19,200 mg/kg diet led to a complex of changes in the endocrine system, thyroid activation being the most prominent. Furthermore, in the highest dose groups a decrease in spermatogenesis in the testes and decreased secretory activity of the prostate or a reduction in the number of corpora lutea in the ovaries were found. A three-generation reproduction study of the same dietary concentrations showed in the two highest dose groups a decrease in fertility which appeared to be reversible upon bromide withdrawal. Macroscopically, no changes in the offspring were observed. From these studies a no-effect level for bromide ion of 240 mg/kg diet was determined, corresponding to a tentative Acceptable Daily Intake (ADI) of 0.12 mg/kg body weight. This is in good agreement with a preliminary ADI of 0.1 mg/kg established in an experiment with human volunteers, but is considerably lower than the ADI of 1 mg/kg estimated by FAO/WHO. It is suggested that bromide exerts an inhibitory effect on the thyroid, resulting in an increased hormonal stimulation of this organ by the pituitary gland."
|
|
Home | Orthoiodosupplementation | Body | Disease | Special Topics | OverviewsThe Iodine Group | Books | Disclaimers | Contact Us | Search
|
||
