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PubMed2000

Oxidative cell damage in Kat-sod assay of oxyhalides as inorganic disinfection by-products and their occurrence by ozonation.

Nine oxyhalides as possible inorganic disinfection by-products were tested for oxidative cell damage by Kat-sod assay with E. coli mutant strains deficient in the active oxygen-scavenging enzymes. Chlorine dioxide, chlorite, and iodate were highly cytotoxic, whereas in the presence of cysteine, bromate (BrO3-) and metaperiodate (IO4-) showed more growth inhibition toward the superoxide dismutase-deficient strains than the wild strain. BrO3- also showed oxidative mutagenicity with cysteine or glutathione ethyl ester in S. typhimurium TA 100. To identify oxyhalides formed by ozonation of raw water containing sea water, the occurrence of ozonation by-products of bromide and iodide was investigated. The results indicate that BrO3- is toxicologically one of the most remarkable oxyhalides detectable in drinking water because IO4- was not detected in the ozonated solution of iodide, and the ozonation condition to lower BrO3- is to keep it neutral in the presence of ammonium ion.

Bromates↗
PubMed1998

Choriocapillary changes and hyperfluorescence on indocyanine green angiography.

BACKGROUND: The purpose of this study is to examine the relationship between pathological changes of the choriocapillaris (CC) and the finding of bright fluorescence on indocyanine green (ICG) angiography. METHODS: An animal model was used, with chorioretinal lesions produced by injecting sodium iodate 3 h, 24 h, 7 days or 14 days previously. The ICG angiographic findings were compared with histology. RESULTS: Three hours after injection, many spots of bright fluorescence were scattered at the posterior pole. Histologically, variable changes in CC endothelial cells were observed. In some regions, the cells remained almost normal morphologically. In other regions, the endothelial cytoplasm was thickened with decreased fenestrations, or precipitation of fibrin in the choroidal interstitium was observed. Twenty-four hours after injection, the area of bright fluorescence had extended beyond that observed after 3 h. Histologically, the cytoplasmic structure of CC endothelial cells was unclear, and the endothelial walls were detached from the basement membrane. When ferritin was administered as a tracer, many ferritin granules were observed in Bruch's membrane. Seven days after injection, the degree of bright fluorescence was reduced as compared with 3 and 24 h after injection. Histologically, the cytoplasm of CC endothelial cells was thinned, but contained few fenestrations. The endothelial walls were detached from the basement membrane. Fourteen days after injection, normal diffuse ICG fluorescence was observed. Histologically, CC endothelial cells exhibited almost normal structure. CONCLUSION: These findings indicate that changes in CC endothelial cells and bright fluorescence on ICG angiography are closely related. ICG angiography should enable clinical evaluation of increased permeability of CC endothelial cells to relatively large molecules.

Animals↗
PubMed1985

Kinetics of macromolecules injected into the subretinal space.

Small, experimental, non-rhegmatogenous retinal detachments (blebs) in rabbit eyes resorbed 50% more slowly when filled with autologous serum than with Hanks' solution. To study the fate of large molecules in the subretinal space, carboxyfluorescein and several sizes of FITC-dextrans were injected into blebs and their movement followed by fluorophotometry. Carboxyfluorescein diffused quickly into the vitreous and was gone from the space after 8 hr. FITC-dextran 10-S (smaller than albumin) also diffused readily into the vitreous and took about 30 hr to be eliminated from the subretinal space. The diffusion of FITC-dextran 70-S and 150-S (both larger than albumin) was markedly slower, and roughly 80% of the 150-S was still present in the subretinal space after 3 days. Since the subretinal fluid in all of these blebs resorbed within 10 hr, the physiologic mechanisms for fluid resorption and elimination of large substances appear to be independent. Damaging the RPE barrier with sodium iodate allowed even the larger FITC-dextrans to exit from the subretinal space.

Absorption↗
PubMed1992

Changes in Müller cell plasma membrane specializations during subretinal scar formation in the rabbit.

The aim of this study was to identify changes in Müller cell plasma membrane specializations during experimentally induced subretinal gliosis in rabbits. When rabbits are dosed with sodium iodate, large expanses of retinal pigment epithelium and photoreceptors are destroyed. They are replaced by a subretinal scar consisting mainly of the ascending processes of Müller cells. These processes transform from the slender, highly polarized structures seen in normal animals into irregular processes that form a glia limitans along the basement membrane of the pigment epithelium, left bare following its degeneration. As the scar processes extend through the subretinal space and contract this basement membrane, they undergo dramatic changes in shape that are especially apparent in three-dimensional computer reconstructions of serial thick sections examined by high-voltage electron microscopy. Other changes involve the intercellular junctions and apical microvilli normally associated with the external limiting membrane. These structures become scattered over the surfaces of the ascending processes and are eventually lost. Loss of microvilli is associated with disappearance of immunostaining for a specific glycoconjugate normally associated with the microvillar plasma membrane. The observations document profound changes in Müller cell structural and functional polarity during subretinal scar formation.

Animals↗
PubMed1984

Selective actions of barium on the c-wave and slow negative potential of the rabbit eye.

The c-wave and slow negative potential (incorporating the slow P111) are both thought to be generated by light-evoked changes in the concentration of potassium surrounding the photoreceptors. We find the intravitreal barium, a blocker of potassium conductance, eliminates the c-wave from the intact rabbit eye but not the slow negative response. However, if the pigment epithelium is damaged by systemic administration of sodium iodate, barium then eliminates the slow negative response.

Animals↗
PubMed2006

Systemically transferred hematopoietic stem cells home to the subretinal space and express RPE-65 in a mouse model of retinal pigment epithelium damage.

Stem cell regeneration of damaged tissue has recently been reported in many different organs. Since the loss of retinal pigment epithelium (RPE) in the eye is associated with a major cause of visual loss - specifically, age-related macular degeneration - we investigated whether hematopoietic stem cells (HSC) given systemically can home to the damaged subretinal space and express markers of RPE lineage. Green fluorescent protein (GFP) cells of bone marrow origin were used in a sodium iodate (NaIO(3)) model of RPE damage in the mouse. The optimal time for adoptive transfer of bone marrow-derived stem cells relative to the time of injury and the optimal cell type [whole bone marrow, mobilized peripheral blood, HSC, facilitating cells (FC)] were determined by counting the number of GFP(+) cells in whole eye flat mounts. Immunocytochemistry was performed to identify the bone marrow origin of the cells in the RPE using antibodies for CD45, Sca-1, and c-kit, as well as the expression of the RPE-specific marker, RPE-65. The time at which bone marrow-derived cells were adoptively transferred relative to the time of NaIO(3) injection did not significantly influence the number of cells that homed to the subretinal space. At both one and two weeks after intravenous (i.v.) injection, GFP(+) cells of bone marrow origin were observed in the damaged subretinal space, at sites of RPE loss, but not in the normal subretinal space. The combined transplantation of HSC+FC cells appeared to favor the survival of the homed stem cells at two weeks, and RPE-65 was expressed by adoptively transferred HSC by four weeks. We have shown that systemically injected HSC homed to the subretinal space in the presence of RPE damage and that FC promoted survival of these cells. Furthermore, the RPE-specific marker RPE-65 was expressed on adoptively transferred HSC in the denuded areas.

Animals↗
PubMedDate not supplied

Validation of simultaneous volumetric and spectrophotometric methods for the determination of captopril in pharmaceutical formulations.

Simple, sensitive and economical simultaneous volumetric and spectrophotometric methods for the determination of captopril have been developed. The methods were based on the reaction of captopril with potassium iodate in HCl medium. Amaranth was used as indicator to detect the end-point of the titration in aqueous layer. The iodine formed during the titration was extracted into CCl4 and subsequently determined spectrophotometrically at 510 nm. The Beer's law was obeyed in the concentration range of 120-520 microg ml-1. Rigorous statistical analyses were performed for the validation of the proposed methods. The proposed methods were successfully applied to the determination of captopril in dosage forms. Comparison of the means of the proposed procedures with those of reference methods using point and interval hypothesis tests showed no statistically significant difference.

Captopril↗
PubMed2006

Full-field ERGs obtained using a contact lens electrode with built-in high intensity white light-emitting diodes in beagle dogs can be applied to toxicological assessments.

We investigated full-field ERGs in beagle dogs using a contact lens electrode with built-in LED. Experiment 1 was performed to determine the appropriate conditions for stimulus intensity and background illumination. We found that full-field ERGs could be recorded under the following conditions: stimulus intensity: -2.5logcd*s/m(2) in rod responses (RRs), 1.2logcd*s/m(2) in maximal responses (MRs), oscillatory potentials (OPs), cone responses (CRs), 30-Hz flicker responses (FRs), and background illumination: more than 25cd/m(2) in CRs and FRs. Experiment 2 was performed to apply full-field ERGs in beagle dogs to the detection of retinal toxicities. A dog was given one 30mg/kg dose of sodium iodate (NaIO(3)) intravenously. ERGs were recorded before administration and 1, 3, 5, 8, 24h, 7 and 14 days after administration of NaIO(3). The RRs disappeared completely at 1h when MRs and OPs decreased. On the other hand, CRs and FRs were recorded even at 8h. All responses disappeared at 24h. These findings indicate that retinal toxicity by NaIO(3) is first expressed in rods, followed by cones. These results suggest that full-field ERGs in beagle dogs using an LED contact lens can be used to evaluate toxic effects on rods and cones separately, with the potential to prove more useful than conventional methods for toxicological assessments of developing pharmaceuticals, and can be applied to it.

Animals↗
PubMed1988

Carboxyfluorescein transfer across the blood-retinal barrier evaluated by quantitative fluorescence microscopy: comparison with fluorescein.

Carboxyfluorescein levels in ocular tissues of normal rats were measured using quantitative fluorescence microscopy and compared with fluorescein levels to determine the extent to which blood-retinal barrier permeability is affected by the difference in lipid solubility of these two dyes. Retinal fluorescence intensity measurements at 2 min after i.v. dye injection were very much lower for carboxyfluorescein than for fluorescein despite similar plasma free dye concentrations. Marked leakage of dye from the optic disc into peripapillary retina was identified. At 1- and 2 hr, retinal levels of the two dyes became more similar, because fluorescein was removed from retina faster than carboxyfluorescein. After sodium-iodate-induced damage of the pigment epithelium, high levels of both dyes were evident in retina, but carboxyfluorescein was localized chiefly within extracellular space whereas fluorescein also densely stained cell somata. The fluorescence intensity levels recorded, which are proportional to the total mass of dye in the tissue, were correspondingly lower for carboxyfluorescein than for fluorescein, indicating that they were markedly affected by the different distribution of the two dyes. To relate tissue fluorescence intensity directly to dye concentration in the extracellular fluid, measurements were obtained from isolated retinas incubated in dye solutions of known concentration. Log-log plots demonstrated a linear relation between fluorescence intensity and medium concentration for both dyes, but retinal fluorescence of carboxyfluorescein, in correspondence with its limited distribution in the tissue space, was consistently less than that of fluorescein. The ratio of carboxyfluorescein to fluorescein fluorescence varied with the retinal layers but was constant for each layer over the concentration range tested. These fluorescence intensity ratios then were used to adjust the in vivo data so that comparison between the two dyes more closely reflected their extracellular dye concentration. With this correction the amount of carboxyfluorescein present in outer retina shortly after dye injection was approx. 1/10 that of fluorescein, indicating that carboxyfluorescein penetrates the pigment epithelium less readily than fluorescein, as expected from the difference in lipid solubility of the two dyes. However, fluorescence of both dyes in retina and presumably in vitreous humor eventually reached similar levels. This is attributed to entry of the dyes at sites of barrier discontinuity, as at the optic disc, and by a difference in their rates of removal from the intraocular compartment.

Animals↗
PubMedDate not supplied

Evidence that a-wave latency of the electroretinogram is determined solely by photoreceptors.

PURPOSE: To identify the retinal cells that determine the a-wave latency of rats. METHODS: Electroretinograms (ERGs) were recorded from the rod-dominated (0.85% cones) retinas of Long-Evans rats following an intravitreal injection of 1 microL of 40 mM 2-amino-4-phosphonobutyric acid to block the activity of the ON pathway of the second order retinal neurons. ERGs were also recorded following an intraperitoneal injection of sodium iodate to destroy the retinal pigment epithelial (RPE) cells. Damage to a large area of the retina was produced by constant light exposure, and focal damage to the retina was induced by argon laser photocoagulation. The effects of age and anesthesia level on the a-wave latency were also determined. RESULTS: Blocking the activity of the ON pathway of the second order retinal neurons did not alter the a-wave latency, and destroying the RPE cells also did not alter the a-wave latency. Damage to a large area of the retina resulted in prolonging the latency but focal retinal damage did not alter the a-wave latency. The a-wave latency was longer in young rat pups but was adult-like by 18 days. The level of anesthesia had no effect on the latency except at very deep stages. CONCLUSIONS: The a-wave latency is determined solely by the activity of the photoreceptors. A prolonged latency would indicate that the photoreceptors are damaged over a large area of the retina.

Aminobutyrates↗
PubMed1994

Iodination of irrigation water as a method of supplying iodine to a severely iodine-deficient population in Xinjiang, China.

Severe iodine deficiency still occurs in many countries, and causes cretinism and mental impairment. In southern Xinjiang province, China, after usual methods of iodine supplementation had failed, we iodinated irrigation water to increase iodine in soil, crops, animals, and human beings. 5% potassium iodate solution, dripped into an irrigation canal for 12 or 24 days, increased soil iodine 3-fold, and crop and animal iodine 2-fold. Median urinary iodine excretion in children increased from 18 to 49 micrograms/L (two groups of similar age). The cost for iodine was US $0.05 per person per year. Soil iodine remained stable over one winter, and dripping of iodine during the second year (US $0.12 per person per year) resulted in a further 4-fold increase in soil iodine and a 1.8-fold increase in iodine in crops. We conclude that iodination of irrigation water is an advantageous and cost-effective method of supplying iodine in southern Xinjiang, and may be useful in other areas dependent on irrigation.

Agriculture↗
PubMed1997

Effect on infant mortality of iodination of irrigation water in a severely iodine-deficient area of China.

BACKGROUND: Hotien county in Xinjiang province, China, is an area of severe iodine deficiency and has a high infantmortality rate. We investigated whether iodine replacement through iodination of the irrigation water would decrease infant mortality. METHODS: We added potassium iodate to irrigation water over a 2 to 4 week period beginning in 1992 in certain areas of three townships (Tusala, Long Ru, and Bakechi). Logistic regression analysis was used to compare the odds ratios for infant and neonatal mortality in treated and intreated areas. FINDINGS: The median urinary iodine concentration significantly increased in women of child-bearing age from < 10 micrograms/L to 55 micrograms/L. Infant-mortality rates decreased in the treated areas of Long Ru (mean [SD] 58.2 [4.4] per 1000 births to 28.7 [7.1] per 1000 births), Tusala (47.4 [12.4] per 1000 births to 19.1 [1.5] per 1000 births), and Bakechi (106.2 [9.5] per 1000 births to 57.3 [7.3] per 1000 births). Similar results were also seen for neonatal mortality. On regression analysis iodine treatment and time were significant independent predictors of infant mortality. INTERPRETATION: Iodine supplementation of irrigation water in areas of severe iodine deficiency decreases neonatal and infant mortality. Iodine replacement has probably been an important factor in the national decrease in infant mortality in China.

Adult↗
PubMed2003

Chemical dosimetry using an iodide/iodate aqueous solution: application to the gamma irradiation of blood.

A method is presented for measuring and verifying the radiation dose in gamma irradiators used for treating blood prior to transfusion. This method employs the iodide/iodate dosimeter (0.6M iodide, 0.1M iodate, and 0.01 borate at pH 9.25) which forms triiodide upon exposure to ionizing radiation; for Cs-137 radiation the G value is 14.1. Samples were placed in a canister and irradiated in a conventional blood bank irradiator containing several Cs-137 sources. The following were exposed: (a) nine 1.5 ml plastic tubes containing dosimetry solution taped inside a 250 ml blood bag, which, in turn, was filled with either water or blood, (b) 50 ml plastic syringes containing varying amounts of dosimetry solution, (c) a whole blood bag containing 250 ml of the dosimetry solution. A water phantom was not used during exposure. The absorbance changes at 352 nm due to triiodide formation were used to determine a dose rate, which was on the order of 10 Gy/min (+/-5%) for all samples measured. This value is consistent with an average time-decayed dose rate for the irradiation volume as determined from the manufacturers calibration of the unit taking into account the heterogeneous nature of the radiation field inside the irradiator and the absence of a water phantom. Because of its sensitivity, ease of operation, and reproducibility, it is suggested that the iodide/iodate dosimetry system be considered for on-site periodic conformation/verification of the radiation dose as part of a quality assurance requirement for blood irradiators.

Blood↗
PubMed1998

Iodine determination in food samples using inductively coupled plasma isotope dilution mass spectrometry.

Two different sample treatment methods are used in connection with inductively coupled plasma isotope dilution mass spectrometry for accurate and precise determinations of iodine traces in food samples. 129I-enriched iodate is applied as a spike compound for the isotope dilution step. Extraction of iodine by tetramethylammonium hydroxide (TMAH) solution at high temperatures in a closed vessel is one of the sample treatment methods. The other one is a complete decomposition of the sample with a mixture of perchloric acid and nitric acid using microwave assistance. By analyzing different certified reference materials (three milk powders with different iodine levels, BCR CRM 63, 150, and 151; bovine liver BCR CRM 185), the accuracy of ICP-IDMS with both sample treatment methods could be demonstrated. The relative standard deviation was typically in the range of 0.6-2.8% for iodine concentrations between 0.1 microgram g-1 and 5 micrograms g-1. The detection limit was 8 ng g-1 using sample weights of 0.8 g. In a round robin test, using two different types of infant food samples, the results of the two ICP-IDMS methods and of an ICP-MS method without the isotope dilution technique, but applying the TMAH extraction procedure, agree very well with the mean of results of all participating laboratories also using ICP-MS/TMAH. However, the ICP-IDMS method is faster, more precise, widely independent of matrix effects, and, therefore, relatively accurate, which makes this method especially attractive for use as a routine method.

Animals↗
PubMed2004

Mechanisms and inorganic byproducts of trihalomethane compounds sonodegradation.

Organic pollutants can be sonodegraded by two pathways: pyrolysis, oxidation by free radicals, or the combination of both. The sonolytic degradation mechanisms and byproducts formation of aqueous trihalomethanes (THMs) were investigated at acoustic frequency of 20 kHz. The main sonodegradation mechanism of the chloroform, dichlorobromomethane, dibromochloromethane, and bromoform was found to be pyrolysis. The sonolysis degradation pathway of iodoform is free radicals oxidation. Hydrogen peroxide, nitrate, chloride, bromide, iodide, and iodate ions were detected and quantified as the inorganic products of the THMs sonication. A total of 48% TOC removal was achieved after a 180-min sonication of the THMs mixture.

Bromides↗
PubMed2005

Structural characterization of the first hydroxo-bridged plutonium compound, (PuO(2))(2)(IO(3))(mu(2)-OH)(3).

The hydrothermal reaction of a (239)Pu(IV) stock solution in the presence of iodic acid and 1 M KOH produces reddish-brown single crystals of (PuO(2))(2)(IO(3))(OH)(3). The structure consists of two-dimensional layers forming in the ac plane and is the first single-crystal structure of plutonium(VI) connected through hydroxide anions. The additional linkage of plutonium centers is completed through iodate ligands.

Crystallography, X-Ray↗
PubMed2002

Evaluation of antioxidant activity of some natural polyphenolic compounds using the Briggs-Rauscher reaction method.

A new method based on the inhibitory effects of antioxidants on the oscillations of the hydrogen peroxide, acidic iodate, malonic acid, and Mn(II)-catalyzed system (known as the Briggs-Rauscher reaction), was used for the evaluation of antioxidative capacity. With this method, which works near the pH of the fluids in the stomach (pH approximately 2), a group of natural compounds present in fruits and vegetables or in medicinal plants assumed to have antioxidant capacity, was tested successfully. The aim of the present study is to evaluate the antioxidative properties of some active principles contained in vegetables and aromatic plants, namely, cynarin (from Cynara scolymus), rosmarinic acid (from Rosmarinus officinalis), echinacoside (from Echinacea species), puerarin (from Pueraria lobata), and oleuropein (from Olea europea). Also studied with the Briggs-Rauscher reaction method was the antioxidant activity of cyanidin 3-O-beta-glucopyranoside (from Citrus aurantium) in order to compare the results with those obtained by other methods. The conclusions on the dependency of the antioxidative activity on the pH of the testing system are given.

Antioxidants↗
PubMed2006

Spatio-temporal behaviors of a clock reaction in an open gel reactor.

The concentration profiles along the feeding direction of a one side fed gel reactor are analyzed for the iodate-arsenous acid reaction. Multiplicity of inhomogeneous stationary solutions is derived. It is also shown that such profiles may undergo oscillatory bifurcations under long range activation conditions. The bifurcation diagram is analyzed using a Galerkin approximation, the asymptotic validity of which is discussed.

Arsenites↗