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PubMed2006

Speciation of iodine in solid environmental samples by iodine K-edge XANES: application to soils and ferromanganese oxides.

A method was developed for speciation of iodine in solid materials using X-ray absorption near-edge structure (XANES). This method was used to identify the iodine species (mainly inorganic iodine) in environmental samples. It was shown that the XANES spectra of iodide and iodate sorbed within solid materials can be simulated by the linear combination of the spectra of iodide and iodate ions in water. The distribution coefficient (Kd) between soil and water was obtained independently for iodide and iodate, based on iodine speciation both in the solid phase, by XANES, and in the aqueous phase, by HPLC-ICP-MS. It was found that the Kd of iodate is larger than that of iodide by a factor of more than six, showing the more soluble nature of iodide. It was suggested that iodate can form in soil even when iodide is injected into the soil-water system under conditions within the iodide-stable field of the Eh-pH diagram of iodine. This is caused by the much higher affinity of iodate for solid surfaces than iodide. In soil samples under various water saturation conditions, or various Eh conditions, the iodide fraction in water increases with decreasing Eh, which results in an increase in the dissolved total iodine fraction in soil water. The speciation method using XANES was also applied to iodine in a natural soil sample and marine ferromanganese oxides. It is suggested that iodine K-edge XANES is a promising tool for determining the iodide/iodate ratio in natural solid samples, which contributes to better understanding of the behavior of iodine at the Earth's surface.

Journal Article↗
PubMed2003

Iodine uptake by spinach (Spinacia oleracea L.) plants grown in solution culture: effects of iodine species and solution concentrations.

A hydroponic experiment was carried out to investigate the effects of iodine species and solution concentrations on iodine uptake by spinach (Spinacia oleracea L.). Five iodine concentrations (0, 1, 10, 50 and 100 microM) for iodate (IO(3)(-)) and iodide (I(-)) were used. Results show that higher concentrations of I(-) (> or =10 microM) had some detrimental effect on plant growth, while IO(3)(-) had little effect on the biomass production of spinach plants. Increases in iodine concentration in the growth solution significantly enhanced I concentrations in plant tissues. The detrimental effect of I(-) on plant growth was probably due to the excessively high accumulation of I in plant tissues. The solution-to-spinach leaf transfer factors (TF(leaf), fresh weight basis) for plants treated with iodide were between 14.2 and 20.7 at different solution concentrations of iodide; TF(leaf) for plants treated with iodate decreased gradually from 23.7 to 2.2 with increasing solution concentrations of iodate. The distribution coefficients (DCs) of I between leaves and roots were constantly higher for plants treated with iodate than those treated with iodide. DCs for plants treated with iodide increased with increasing solution concentrations of iodide, while DCs for plants treated with iodate (around 5.5) were similar across the range of solution concentrations of iodate used in this experiment. The implications of iodine accumulation in leafy vegetables in human iodine nutrition are also discussed.

Humans↗
PubMed2002

Combating iodine deficiency: lessons from China, Indonesia, and Madagascar.

This study investigated the factors contributing to a successful and sustainable elimination of iodine-deficiency disorders, drawing from salt fortification experiences in China, Indonesia, and Madagascar. Government officials, salt farmers, salt producers, and wholesalers were interviewed to collect data during field visits. Analyses used in the study include simple correlation, and wherever data permit, regression. The study found that measures crucial for combating iodine deficiency include raising public awareness of the disorders, ensuring easy access to iodated salt, promoting compliance in the salt industry, and monitoring and enforcement. Factors that ensure a reliable supply of iodated salt are equally important as those that create the demand for it. Governments must ensure that surveillance and enforcement mechanisms are functioning right from the time that salt iodation is made compulsory. For sustainability during later years, the adequacy of iodine in iodated salt must be monitored, and incentives must be modified as needed to increase compliance rates in the salt industry. Once national coverage of iodated salt reaches over 90%, the government can concentrate on fine-tuning and targeting resources at areas with a low consumption of iodated salt. Elimination of micronutrient deficiencies has a long-term impact on public health; moreover, poorer segments of the population, who are more vulnerable to such deficiencies, have more to gain from fortification programs. Thus, lessons from the successful elimination of iodine-deficiency disorders are valuable for future similar micronutrient activities.

Awareness↗
PubMed1975

[Effectiveness of potassium iodide in ovarian cysts in cows].

A trial was carried out with the treatment of a total of 64 cows having ovarial cysts. Thirty-one of the animals were given potassium iodate in the course of seven days at rates of 3, 4, 5, 6, 7, 8 and 9g with the concentrates, and thirty-three were offered potassium iodate at the same rates in the form of a 1 per cent solution. The medical treatment was performed along with the study of the blood serum for total protein and protein fractions, and the examination of the thyroid activity by means of the factor F after the Modestov-Arsenyev's method. The following conclusions were made: 1. The administration of potassium iodate with the concentrates for 7 days at the rates mentioned above produces a good therapeutic effect, is fully absorbed (as found in the cysts content), and total conception amounts to 86.6 per cent. 2. The albumin level in the serum rises by 1.9 per cent in cows given potassium iodate with the concentrates, and by 1.7 per cent in cows given potassium iodate as a 1 per cent solution. 3. Factor F shows decrease by 28 per cent in animals treated via the concentrated fodder, and by 38.6 per cent in cows offered potassium iodate as 1 per cent solution.

Animals↗
PubMed1984

RPE destruction causes choriocapillary atrophy.

The authors have obtained evidence that destruction of the retinal pigment epithelium (RPE) causes choriocapillaris (CC) atrophy. The observations led us to hypothesize that the RPE modulates CC structure and function. Rabbits received injections of sodium iodate, which selectively destroyed the RPE. The authors killed the rabbits at various times after iodate and examined the RPE and CC by fluorescein angiography, fundus photography, and light and electron microscopy. Fluorescein angiography and fundus photography revealed a pattern of retinopathy similar to that described by other investigators, eg, blood-retinal barrier breakdown and the patchy nature of the RPE/CC degeneration. One week after injection of iodate, the RPE transformed into a mixture of flattened, depigmented cells and plump, highly pigmented ones lying along Bruch's membrane. The CC appeared normal by light microscopy, but electron microscopy revealed changes indicating CC atrophy: degenerating endothelial cells (EC), EC that appeared normal but had reduced numbers of fenestrae, and pericapillary basal laminae that looped away from the endothelium, as if the latter had shrunk. One month after iodate, patches of Bruch's membrane were devoid of RPE, which was replaced by scar tissue. The CC was markedly atrophic over these patches, having reduced numbers of profiles and smaller lumina in those which remained. The CC appeared normal over areas where RPE remained. Eleven weeks after iodate, the light microscopic picture parallelled that seen 1 month after injection, but the patchy RPE degeneration was more extensive. By electron microscopy, the CC profiles over areas devoid of RPE showed severe atrophy. Degenerating EC were more numerous. EC adjacent to areas of RPE loss had few or no fenestrae. Here, capillaries were encased in dense, collagenous, connective tissue, unlike the CC of normal rabbits. These changes were not seen where the RPE still covered Bruch's membrane. These observations suggest that RPE modulates CC structure and function. The authors propose that a diffusible vascular modulating factor produced by RPE cells does this.

Animals↗
PubMed1994

The rate and source of albumin entry into saline-filled experimental retinal detachments.

PURPOSE: To investigate the rate and source of albumin entry into experimental nonrhegmatogenous detachments. METHODS: Detachments were made in Dutch rabbits by injecting Hanks' balanced salt solution into the subretinal space through a micropipette. Subretinal fluid was withdrawn 0 to 4 hours later through a similar micropipette and analyzed for osmolality and albumin content (by gel electrophoresis). Sodium iodate was injected intravenously in some rabbits to damage the retinal pigment epithelium (RPE). In some rabbits fluorescein isothiocyanate albumin (FITC-albumin) was injected intravitreally or intravenously to measure its entry into the subretinal fluid by fluorophotometry. Results from 4 to 8 eyes were averaged for each data point. RESULTS: The albumin concentration and total amount of albumin in the subretinal fluid increased steadily over 4 hours in retinal detachments initially filled with Hanks' solution. Pretreating rabbits with sodium iodate injection resulted in a 50-fold increase in the rate of albumin entry, although the levels were still low relative to those of serum. Intravitreal FITC-albumin entered the subretinal fluid at a rate independent of sodium iodate damage, but intravenous FITC-albumin only entered the subretinal space after RPE damage. Subretinal fluid osmolality remained within the range of 291 to 294 mOsm/kg, irrespective of sodium iodate damage or differences in the rate of fluid absorption. CONCLUSIONS: These results indicate that albumin can diffuse into the rabbit subretinal space from both vitreous and bloodstream, although entry from serum requires damage to the RPE. Subretinal fluid appears to be transported actively (control eyes) or passively (iodate-damaged eyes) out of the subretinal space, despite albumin entry and without major osmolar shifts.

Animals↗
PubMed2005

Synthesis, structure, and spectroscopic properties of Am(IO3)3 and the photoluminescence behavior of Cm(IO3)3.

We have prepared Am(IO(3))(3) as a part of our continuing investigations into the chemistry of the 4f- and 5f-elements' iodates. Single crystals were obtained from the reaction of Am(3+) and H(5)IO(6) under mild hydrothermal conditions. Crystallographic data on an eight-day-old crystal are (21 degrees C, Mo Kalpha, lambda = 0.71073 Angstroms): monoclinic, space group P2(1)/c, a = 7.2300(5) Angstroms, b = 8.5511(6) Angstroms, c = 13.5361(10) Angstroms, beta = 100.035(1) degrees, V = 824.06(18), Z = 4. The structure consists of Am(3+) cations bound by iodate anions to form [Am(IO(3))(8)] units, where the local coordination environment around the americium centers is a distorted dodecahedron. There are three crystallographically unique iodate anions within the structure that bridge in both bidentate and tridentate fashions to form the overall three-dimensional structure. Repeated collection of X-ray diffraction data with time for a crystal of (243)Am(IO(3))(3) revealed an anisotropic expansion of the unit cell, presumably from self-irradiation damage, to generate values of a = 7.2159(7) Angstroms, b = 8.5847(8) Angstroms, c = 13.5715(13) Angstroms, beta = 99.492(4) degrees, V = 829.18(23) after approximately five months. The Am(IO(3))(3) crystals have also been characterized by Raman spectroscopy and the spectral results compared to those for Cm(IO(3))(3). Three strong Raman bands were observed for both compounds and correspond to the I-O symmetric stretching of the three crystallographically distinct iodate anions. The Raman profile suggests a lack of interionic vibrational coupling of the I-O stretching, while intraionic coupling provides symmetric and asymmetric components that correspond to each iodate site. Photoluminescence data for both Am(IO(3))(3) and Cm(IO(3))(3) are reported here for the first time. Assignments for the electronic levels of the actinide cations were based on these photoluminescence measurements and indicate the presence of vibronic coupling between electronic transitions and IO(3)(-) vibrational modes in both compounds.

Journal Article↗
PubMed1982

Fluorometric studies on the blood-retinal barrier in experimental animals.

Fluorophotometry was used to evaluate the blood-ocular barrier in rats following streptozocin-induced diabetes, experimental systemic hypertension, sodium iodate treatment, diet-induced galactosemia, and aldose reductase inhibitors. After administration of intravenous (IV) fluorescein sodium, diabetes, hypertension, or sodium iodate treatment resulted in an increased vitreous accumulation of IV fluorescein. Accumulation of dextran-labeled fluorescein (3,000 and 19,000 molecular weight [mol wt]) was not increased in diabetic or sodium iodate-treated animals. However, 3,000-mol wt dextran-labeled dye accumulated in the vitreous of hypertensive rats. The disappearance of fluorescein injected into the vitreous was significantly delayed in diabetic and sodium iodate-treated rats, whereas this rate was normal in hypertension animals. Galactosemia did not alter vitreous fluorophotometric measurements. Pretreatment for systemic effects with aldose reductase inhibitors did not correct the vitreous fluorophotometric measurements of diabetic rats.

Aldehyde Reductase↗
PubMed1997

Two types of modified cardiac Na+ channels after cytosolic interventions at the alpha-subunit capable of removing Na+ inactivation.

Failure of inactivation is the typical response of voltage-gated Na+ channels to the cytosolic presence of proteolytic enzymes, protein reagents such as N-bromoacetamide (NBA) or iodate, and antibodies directed against the linker between domains III and IV of the alpha-subunit. The present patch clamp experiments with cardiac Na+ channels aimed to test the hypothesis that these interventions may provoke the occurrence of non-inactivating Na+ channels with distinct kinetic properties. A site-directed polyclonal antibody (anti-SLP2, target sequence 1481-1496 of the cardiac Na+ channel alpha-subunit) eliminated fast Na+ inactivation to induce burst activity which was accompanied by the occurrence of two open states. A deactivation process terminated channel activity during membrane depolarization proceeding with time constants of close to 40 ms (at -40 mV). NBA-modified and iodatemodified Na+ channels were kinetically indistinguishable from the anti-SLP2-modified type since they likewise deactivate and, thus, attain an only moderate Po of close to 20%. This is fundamentally different from the behaviour of enzymatically-modified Na+ channels: after cytosolic proteolysis with alpha-chymotrypsin, trypsin or pronase, mean Po during membrane depolarization amounted to approximately 40% because deactivation operated extremely slowly and less efficiently (time constants 100-200 ms at -40 mV, as a minimum) or was virtually non-operating. Invitro cleavage of the synthetic linker sequence 1481-1496 confirmed that this part of the alpha-subunit provides a substrate for these peptidases or reactants for NBA but cannot be chemically modified by iodate. This iodate resistance indicates that iodate-modified Na+ channels are based on a structural alteration of still another region which is also involved in Na+ inactivation, besides the linker between domains III and IV of the alpha-subunit. Endogenous peptidases such as calpain did not affect Na+ inactivation. This stresses the stochastic nature of a kinetic peculiarity of cardiac Na+ channels, mode-switching to a non-inactivating mode.

Acetamides↗
PubMed2004

Effects of ozonation on the speciation of dissolved iodine in artificial seawater.

Iodine in the form of iodide is required for synthesis of tri-iodothyronine and thyroxine in fish. Iodine chemical speciation in aliquots of raw artificial seawater mix was measured before, during, and after exposure for fixed time periods to air only and to concentrations of ozone required to achieve oxidation-reduction potentials typical of a protein skimmer (400 mV) and an ozone contact chamber (800 mV). Chemical species of iodine were also measured in tank water from a large, recirculating, ozonated aquarium system that has a low-grade incidence of thyroid lesions (e.g., thyroiditis, hyperplasia, adenoma, and adenocarcinoma) in its fish. With increasing exposure to ozone, concentrations of iodide and dissolved organic iodine (DOI) decreased, whereas iodate levels increased. As a result of exposure to 400 mV, iodide concentration dropped to less than half the amount found in raw artificial seawater mix. After exposure to 800 mV, initial iodide levels decreased by 67%, and DOI became undetectable, whereas iodate concentration increased by 155%, with no remarkable change in total iodine concentration. These results indicate ozone-induced conversions from iodide to iodate, and DOI to iodide or iodate (or both). Iodide and DOI were not detectable in the aquarium system's water samples. Ozonation of artificial seawater may alter the relative concentrations of iodine species in a closed tank system, so that iodide supplementation of the diet or tank water of captive teleosts and elasmobranchs living in ozonated seawater is advisable.

Animals↗
PubMed1983

Chemical forms of radioactive iodine in seawater and its effects upon marine organisms.

Chemical forms of radioactive iodine and its effects upon marine organisms were studied by the tracer experiments. Seaweeds or fish were held in the aquarium in which the 125I tracer in either iodide or iodate form was inoculated. Iodide form of 125I was taken by Dorome (Chasmichthys gulosus) with the concentration factor of about 10 and excreted with the biological half-life of 15 days, while iodate form of 125I was not taken up appreciably and the concentration factor did not greatly exceed unity. Uptake and loss of 125I were studied as well for 3 species of seaweeds, Hijiki(Hizikia fusiforme), Nejimoku (Sargassum sagamianum) and Tsunomata (Chondrus ocellatus). Iodate form of 125I was accumulated less than iodide form by these seaweeds but the concentration factor of iodate by these seaweeds was very high compared to those by fish.

Animals↗
PubMed1983

The resorption of subretinal fluid after diffuse damage to the retinal pigment epithelium.

We studied the role of the retinal pigment epithelium (RPE) in the resorption of different subretinal fluids from under small experimental retinal detachments (blebs) in the rabbit. Damaging the RPE with sodium iodate caused the resorption time, for blebs made with an ionic solution (Hanks'), to decrease from 2-6 hours to only about 30 minutes. Blebs made with sucrose also absorbed much more quickly after iodate. However, blebs made with autologous serum resorbed no faster after iodate. We conclude that iodate destroys the membrane barrier properties of the RPE, allowing subretinal fluid to cross freely according to oncotic pressure. We postulate that in the normal eye, where osmotic fluid movement is low because of the high resistance barrier, the RPE must transport fluid actively to keep the subretinal space dehydrated.

Absorption↗
PubMed2003

Cation-cation interactions in neptunyl(V) compounds: hydrothermal preparation and structural characterization of NpO2(IO3) and alpha- and beta-AgNpO2(SeO3).

The hydrothermal reaction of NpO(2) with IO(3)(-) in the presence of nitrate results in the formation of NpO(2)(IO(3)) (1). Under similar conditions, NpO(2) reacts with AgNO(3) and SeO(2) to yield alpha-AgNpO(2)(SeO(3)) (2) and beta-AgNpO(2)(SeO(3)) (3). The structure of 1 consists of distorted pentagonal bipyramidal Np(V) centers that are bridged by iodate anions. In addition, the oxo atoms of the neptunyl(V) cations coordinate adjacent Np(V) centers creating layers that are linked into a three-dimensional network structure by the iodate anions. The structure is polar owing to the alignment of the stereochemically active lone pair of electrons on the iodate anions along the c-axis. alpha-AgNpO(2)(SeO(3)) (2) forms a layered structure consisting of hexagonal bipyramidal NpO(8) polyhedra that are bound by chelating and bridging selenite anions. The primary and secondary structures of 3 are similar to those of 1, and neptunyl-neptunyl interactions are partially responsible for the creation of a three-dimensional network structure. However, the selenite anions in 3 are rotated with respect to the iodate anions found in 1, and the structure is centrosymmetric. The network found in 3 consists of interconnecting, approximately square channels that house the Ag(+) cations. A bond-valance sum parameter of 2.036 A for Np(V) bound exclusively to oxygen has been developed with b = 0.37 A. Crystallographic data: 1, orthorhombic, space group Pna2(1), a = 13.816(2) A, b = 5.8949(8) A, c = 5.5852(8) A, Z = 4; 2, monoclinic, space group P2(1)/n, a = 4.3007(3) A, b = 9.5003(7) A, c = 11.5877(9) A, beta = 95.855(1) degrees, Z = 4; 3, triclinic, space group Ponemacr;, a = 7.1066(6) A, b = 8.3503(7) A, c = 8.3554(7) A, alpha = 89.349(1) degrees, beta = 77.034(1) degrees, gamma = 76.561(1) degrees, Z = 2.

Journal Article↗
PubMed1985

A rapid air titration method for determining SO2 concentration in inhalation chambers.

A rapid air titration method for determining SO2 concentration in inhalation chambers has been validated using the pararosaniline-formaldehyde (PRA) method of West and Gaeke. This air-titration (iodate) method is an adaptation of iodometric methods using a starch indicator. Potassium iodate and an excess of potassium iodide are used in the reaction. Sampling is completed in ten minutes or less and concentration is calculated by use of a simple formula. Linear equations were derived over the range of concentrations from 0.5 to 100 ppm SO2 for uncorrected iodate bubbler results, data corrected for tandem bubbler concentrations and data corrected for mean iodate bubbler efficiency. Linear correlation with the PRA method over this range was 0.999 for all three sets of data.

Atmosphere Exposure Chambers↗