Synthesis and characterisation of [Pt2(μ-S)(μ-I)(PPh3)4] - A cationic iodo analogue of the metalloligand [Pt2(μ-S)2(PPh3)4]

Reaction of [Pt₂(μ-S)₂(PPh₃)₄] with a number of transition metal-iodo complexes leads to the formation of the cationic iodo analogue [Pt₂(μ-S)(μ-I)(PPh₃)₄]⁺, identified using electrospray ionisation mass spectrometry (ESI MS). Synthetic routes to this complex were developed, using the reaction of [Pt₂(μ-S)₂(PPh₃)₄] with either [PtI₂(PPh₃)₂] or elemental iodine. The complex was characterised by NMR spectroscopy, ESI MS and an X-ray structure determination, which reveals the presence of a planar, disordered {Pt₂SI}⁺ core. Monitoring the iodine reaction by ESI MS allows the identification of various iodine species, including the short-lived intermediate [Pt₂(μ-S)₂(PPh₃)₄I]⁺, which allows a mechanism for the reaction to be proposed.     

Determination of iodide in urine using electrospray ionization tandem mass spectrometry

A rapid and sensitive electrospray ionization (ESI) tandem mass spectrometry (MS–MS) procedure was developed for the determination of iodide (I⁻). A gold (Au) and I⁻ complex was formed immediately after the addition of the chelating agent NaAuCl₄ to I⁻ solution, and was extracted with methyl isobutyl ketone. One to five microliters of the extract were injected directly into an ESI–MS–MS instrument. I⁻ quantification was performed by selecting reaction monitoring of the product ion I⁻ at m/z 127 derived from the precursor ion ¹⁹⁷AuI₂⁻ at m/z 451. I⁻ concentration was measured in the quantification range from 10⁻⁷ to 10⁻⁵ M using 50 μL of solution within 10 min. Iodate was reduced to I⁻ with ascorbic acid and determined. I⁻ concentration in reference urine 2670a was measured after treatments.     

Effect of different iodide intake during pregnancy and lactation on thyroid and cardiovascular function in maternal and offspring rats

ObjectiveWe aimed to investigate the impact of different iodide intake during pregnancy and lactation on iodine concentration in urine and serum, fatty acid metabolism, thyroid and cardiovascular function in maternal and offspring rats.MethodsPregnant rats were randomly assigned to four groups: normal adult iodide intake (NAI, 7.5 μg/d), normal pregnant iodide intake (NPI, 12.5 μg/d), 5 times (5 HI, 62.5 μg/d) and 10 times higher-than-normal pregnant iodide intake (10 HI, 125 μg/d). The maternal rats were continuously administered potassium iodide until postnatal day 16 (PN16). Thyroid function was measured by enzyme-linked immunosorbent assay (ELISA). The iodine concentration in urine and serum were detected by inductively coupled plasma mass spectrometry (ICP-MS). The messenger ribonucleic acid (mRNA) expressions of Krüppel-like factor 9 (KLF9) and thioredoxin reductase 2 (Txnrd2) were measured using quantitative real-time polymerase chain reaction (RT-qPCR). Characteristic distribution of KLF9 expression and its interaction with TRβ was assessed by immunohistochemical and immunofluorescence staining. Serum fatty acids were analyzed by Liquid Chromatography-Mass Spectrometry (LC-MS). Cardiac function and blood pressure were measured by echocardiography and a non-invasive tail-cuff system.ResultsHigh iodide intake (5 HI and 10 HI) during pregnancy and lactation results in increased urinary iodine concentration (UIC), serum total iodine concentration (STIC) and serum non-protein-bound iodine concentration (SNBIC) in both maternal and offspring rats, along with significantly increased FT3 and its target gene expression of KLF9. In maternal rats of both 5 HI and 10 HI groups, systolic blood pressure (SBP) was significantly higher, the increased SBP was significantly correlated with the increased UIC (r = 0.968, p = 0.002; r = 0.844, p = 0.035), KLF9 (r = 0.935, p = 0.006; r = 0.954, p = 0.003) and the decreased Txnrd2 (r = −0.909, p = 0.012; r = −0.912, p = 0.011). In maternal rats of 10 HI group, cardiac hyperfunction with increased LVEF, LVFS and decreased LVESD were observed. The increased LVEF and decreased LVESD were significantly correlated with UIC, STIC and SNBIC (r = 0.976, p = 0.001; r = 0.945, p = 0.005; r = 0.953, p = 0.003; r = −0.917, p = 0.01; r = −0.859, p = 0.028; r = −0.847, p = 0.033), LVEF, LVFS and LVESD were significant correlated with KLF9 (r = 0.950, p = 0.004; r = 0.963, p = 0.002; r = −0.990, p = 0.0002) and Txnrd2 expression (r = −0.979, p = 0.001; r = −0.915, p = 0.01; r = 0.933, p = 0.007), and the decreased LVESD was correlated with decreased epoxyeicosatrienoic acid (EET) metabolites: 5,6-EET, 8,9-DHET and 11,12-DHET (r = 0.999, p = 0.034; r = 1.000, p = 0.017; r = 1.000, p = 0.017). While in offspring rats, no significant change in SBP and cardiac function was found. STIC and SNBIC were much lower than those in maternal rats, and eicosapentaenoic acid (EPA) metabolites (9-HEPE, 15-HEPE and 14,15 DiHETE) were significantly increased.ConclusionIn addition to thyroid hormones, STIC, SNBIC, KLF9, Txnrd2, EET and EPA metabolites might be promising biomarkers in high iodide intake-induced thyroid and cardiovascular function.     

Bromine in soils and peats

Summary Determinations were made by an iodometric method and by gas-liquid chromatography (g.l.c.) of inorganic bromide and total bromine in two soils of widely differing organic matter content, and in eight types of peat. The volumetric method is responsive to both bromide and iodide and gave a combined value. The g.l.c. method is halogen specific and gave individual values for bromide and iodide. Inorganic bromide represented only a small fraction (1.1% and 8%) of the total bromine in the soils, and was an even smaller fraction (0–1%) in the peats. The highly organic soil contained 141 μg total Br/g dry wt compared with 14 μg/g in the other soil. Total Br in the peats ranged from 11–116 μg/g. The organic soil contained an appreciable amount of total I (46 μg/g), while the total I content of the peats ranged from 3–18 μg/g. The possibility is considered that during the decomposition of peat added to soil, organic Br is released which might act as a potential source of inorganic bromide available to plants, so contributing to bromide residues in edible crops.     

Correlation between thyroid-follicle fusion and structural modifications of the epithelial cells

Summary Changes in thyroid structure induced by a decrease in TSH or iodide-dependent stimulation were quantified by stereological analysis of light micrographs. Studies were carried out on intact (R5) and hypophysectomized (R 5H) rats receiving 5 g iodide, and on intact rats (R5O) receiving 50 g iodide daily.For R 5H- and R5O-thyroids, the mean parameters of the epithelial cells, height, volume and lateral membrane area, were smaller than those of R 5-thyroids. An inverse shift was observed for the apical membrane area, whereas the peripheral membrane area was unchanged. The number of epithelial cells was similar in each of the three groups; however, the number of follicles was greater in R 5-thyroids, suggesting that follicular fusion occurs in R 5O- and R 5H-thyroids. This was confirmed by direct observation.The present results demonstrate that in adult rats a lack of TSH or an increased iodide diet (insufficient to produce a physiopathological state) induce follicle fusion probably by means of cellular reorganization. This increase in follicle size could be involved in the regulation of thyroid iodine turnover.     

Heavier halides of transition metals by halide exchange

Examples are reported of heavier (bromides or iodides) metal halides of the d or f transition series being prepared through the halide exchange reaction from the lighter congeners (fluorides or chlorides, easily prepared by direct combination from the elements), by using gaseous hydrogen halides HX or alkyl halides RX in an anhydrous organic solvent at room temperature or even below. This represents a considerable improvement with respect to the traditional high-temperature experimental procedures from the elements. Thermodynamic data show that this synthetic route is of quite general validity.     

Interaction of measles virus vectors with Auger electron emitting radioisotopes

A recombinant measles virus (MV) expressing the sodium iodide symporter (NIS) is being considered for therapy of advanced multiple myeloma. Auger electrons selectively damage cells in which the isotope decays. We hypothesized that the Auger electron emitting isotope 125I can be used to control viral proliferation. MV was engineered to express both carcinoembryonic antigen and NIS (MV-NICE). Cells were infected with MV-NICE and exposed to 125I with appropriate controls. MV-NICE replication in vitro is inhibited by the selective uptake of 125I by cells expressing NIS. Auger electron damage is partly mediated by free radicals and abrogated by glutathione. In myeloma xenografts, control of MV-NICE with 125I was not possible under the conditions of the experiment. MV-NICE does not replicate faster in the presence of radiation. Auger electron emitting isotopes effectively stop propagation of MV vectors expressing NIS in vitro. Additional work is necessary to translate these observations in vivo.     

Effects of speciation on partitioning of iodine in aqueous biphasic systems and onto ABEC resins

Polyethylene glycol (PEG)-aqueous biphasic systems (ABS) and PEG-grafted aqueous biphasic extraction chromatographic (ABEC) resins have been shown to remove inorganic species from environmental and nuclear wastes. The partitioning behavior of several iodide species (iodide, iodine, triiodide, iodate, and 4-iodo-2,6-dimethylphenol (I-DMP)) have been studied for PEG (MW 2000)-salt systems and ABEC resins. Iodide partitioning to PEG-rich phases or onto ABEC resins can be enhanced by derivatization with 2,6-dimethylphenol to form 4-iodo-2,6-dimethylphenol or by addition of I(2) to form triiodide. Conversely, iodide partitioning to the PEG-rich phase or onto ABEC resins is reduced by oxidation of iodide to IO(3)(-). Partitioning studies of iodide, iodate, and iodine in a PEG-ABS are compared to results using ABEC resins.     

Iodide accumulation into thyroid Golgi vesicles

Pig thyroid Golgi vesicles incubated in a suitable medium were able to concentrate iodide from the medium. This trapping required the integrity of the vesicles, was time- and temperature-dependent, and was inhibited by a competitive inhibitor of iodide active transport (perchlorate), suggesting a facilitated transport mechanism.