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The mutagenicity of 14 organotin compounds which have been reported to be environmental pollutants, their environmental metabolites and inorganic tin (SnCl4) was studied. The experiments were carried out by a modification of the conventional Salmonella assay. Each tested chemical was removed by washing the tested strain with phosphate buffer, before the strain with top agar was poured onto minimal glucose agar. By this method, we were able to estimate the mutagenicity of organotin compounds which had antibacterial activity. It was apparent that mono-n-butyltin oxide, n-butyltin trichloride, di-n-butyltin dichloride, tri-n-butyltin chloride, bis-(tri-n-butyltin)-oxide and dimethyltin dichloride were mutagens on Salmonella typhimurium TA100 and bis-(tri-n-butyltin)-oxide showed the highest mutagenicity. With S. typhimurium TA98, di-n-butyltin dichloride was found to be a mutagen.
Two HEDP complexes of technetium (either Tc-99 or a mixture of Tc-99 and Tc-99m) have been prepared without the use of stannous ion. The first, Tc(NaBH4)-HEDP, is synthesized by reduction of TcO4- with NaBH4 in the presence of excess HEDP; this is analogous to the preparation of Tc(Sn)-HEDP in commercial kits wherein SN(II) functions as the reductant. The second, Tc-HEDP, is prepared by substitution of HEDP onto the pre-formed, pre-reduced, technetium center TcBr62-. The HEDP-to-Tc ratio in Tc-HEDP was found to be 1.0 by double-labeling procedures (Tc-99 and [3H]HEDP), implying that in solution this material is polymeric or at least dimeric. Preparations of Tc(NaBH4)-HEDP and Tc-HEDP with Tc-99m are excellent bone-imaging agents in both rats and dogs. Tissue distribution studies in rats show that uptake of Tc(NaBH4)-HEDP and Tc-HEDP by the bone is at least equivalent to that achieved by Tc(Sn)-HEDP prepared in commercial kits with Sn(II) as the reductant. Tin is therefore not necessary for the bone-seeking properties of Tc(Sn)-HEDP, and the in vivo distribution of a given HEDP radiotracer seems to depend primarily on the presence of the HEDP ligand and not on the exact nature of the technetium complex itself. Synthesis of technetium radiotracers by a substitution route, rather than by redox, is practicable; this route has the potential of introducing hitherto unattainable flexibility and subtlety into the preparation of technetium radiotracers.
The chemical and biological characteristics of two dimercaptosuccinate kits were examined and compared: TcP-5 (produced at the Boris Kidric Institute - Vinca) in the freeze-dried form and MPI - the aqueous solution of tin dimercaptosuccinate. The radiochemical composition of the injection solutions was examined by various methods and the method of ascending paper chromatography in 50% aqueous methanol was found as satisfactory. Both preparations has similar compositions. Both preparations showed maximum renal concentrations 3-4 hrs after injection. Liver uptake of MPI was higher than that of TcP-5. The bench-life of both preparations was compared by measuring organ distribution. TcP-5 had a bench-life at least six hrs with a kidney/liver uptake ratio from 5.60 to 8.52, whereas MPI had a satisfactory bench-life of less than half an hour after labelling; thereafter, hepatic concentration rose and the kidney/liver uptake ratio dropped to 1.64.
Studies of the chemistry of preparation of tin chelate 2.3-dimercaptosuccinic acid (DMS) complexed with 99mTc with respect to its biological properties have been made. We have varied molar ratio of reactants (DMS:Sn/II/), concentration of Sn-DMS chelate and pH of 99mTc-DMS injection solution and examined their influence on biodistribution. Biodynamics of labeled solution at time intervals of from 0.5 to 4 h have also been measured. Animal experiments were carried out on mice and rats. Radiochemical purity was checked by paper chromatography, thin-layer chromatography, and gel-filtration through Bio-Gel P-2. A sterile, pyrogen-free lyophilized "kit" for labeling, stable for 6 months, was made on the basis of achieved results. The results of its clinical application are also reported.
The objective of this study was to determine the interaction of modified bilayer lipid membranes (BLMs) with lead and tin organoderivatives. The relative depolarization, of the lipid membrane, caused by organo metals, was used to estimate their activity. Dodecyltrimethylammonium bromide (TMDA) and sodium dodecylsulfonate (AS-12) were used to modify BLMs. The trialkylderivatives of tin (IV) were found to be the most active towards the lipid membrane, whereas dialkyltin (IV) and trialkyllead (IV) derivatives were less active. Also, a correlation exists between depolarization activity and the lipophilicity of organo metal hydrolysis products. The surface charge of modified membranes had a secondary influence on depolarization efficiency of the tin and lead derivatives.
Amalgam tattoos occur when small particles of dental amalgam, composed largely of silver (Ag) and mercury (Hg), are inadvertently implanted into oral soft tissues during dental procedures. Metallothioneins (MTs) are ubiquitous, low molecular weight, cysteine-rich, metal-binding proteins that are inducible by many agents including metals and may be involved in the detoxification of toxic metals such as Hg. In this study, the correlation between MT expression and amalgam tattoos in human gingiva was investigated using energy-dispersive X-ray microanalysis (EDX) and immunohistochemical techniques. Light microscopically, amalgam tattoos presented as either fine granular particles or larger discrete opaque globular particles in connective tissues. EDX revealed the smaller particles to be silver sulphide (Ag(2)S), while the larger particles exhibited a shell of Ag(2)S that contained irregularly distributed masses of Ag and Hg. Particles of tin (Sn) were also found. No MT staining was observed in collagen, fibroblasts or blood vessels in areas exhibiting abundant amounts of embedded fine granular Ag(2)S particles. Blood vessels exhibiting relatively few amalgam particles stained positively for MT. Cells with the morphological features of histiocytes located directly adjacent to larger pieces of amalgam showed intense MT staining. These results indicate that amalgam tattoos contain no Hg or free Ag except in large globular pieces of amalgam, which still contain Hg and which induce MT expression in adjacent histiocytes. This suggests that Hg leaching from impacted dental amalgam particles induces MT, while residual Ag(2)S and Sn particles do not. MT may therefore act to reduce Hg exposure in patients with amalgam tattoos.
During the setting of dental amalgam, silver-mercury (gamma1) and tin mercury (gamma2) intermetallic compounds (phases) are formed. Since these compounds have distinct crystalline forms, they may be discerned on the surface of a setting sample. Visual identification of these phases on polished and etched samples is often difficult and, hence, surface morphology studies have an advantage in following the stages of the setting reaction. The purpose of this investigation was to use high-resolution light microscopy to follow the course of the setting reaction. Amalgam specimens were triturated and condensed against glass plates under pressure. The sample surfaces were then photographed under a high-resolution metallographic microscope using oblique illumination. The roughness of four samples for each alloy type was determined with a surface profile analyzer at times between ten minutes and 23 hours after trituration. An electron microprobe was used to identify the gamma1 and gamma2 phases. The gamma1 phase had a polyhedramorphology, and the gamma2 crystals formed intermeshed smooth areas. During the setting reaction, the average times for the roughness to reach 95% of the final value were 189, 227, 96, 65, and 116 minutes after trituration for the various amalgam types studied. All alloys tested required polishing several hours after trituration.
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Pulsed field gradient (1)H NMR spectroscopy has been applied to investigate the association behavior of the Sn(12)-oxo cluster macrocation [(BuSn)(12)O(14)(OH)(6)](2+) with two different and smaller anions, p-toluenesulfonate (PTS(-)) and diphenylphosphinate (Ph(2)PO(2) (-)). By monitoring the translational diffusion coefficients of the various species involved, it is shown that the association depends on the anion involved and on the solvent used. Moreover, the possibility to individually monitor the diffusion characteristics of multiple anionic and cationic species in mixtures, by virtue of resolved (1)H resonances available from each species, allows us to evidence the occurrence of ion exchange in such systems. Thus when [(BuSn)(12)O(14)(OH)(6)](PTS)(2) is mixed with two equivalents of Ph(2)PO(2)NMe(4), PTS(-) is displaced by Ph(2)PO(2) (-), highlighting the greater affinity of the organotin macrocation for the diphenylphosphinate. This example clearly illustrates the potential of pulsed field gradient (1)H NMR spectroscopy in inorganic/organometallic chemistry, to follow preferential ion pairing in multi-ion systems at the level of each individually charged species.
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Using a laser ablation/inert buffer gas ion source coupled with a reflectron time-of-flight mass spectrometer, the gas-phase reactions between the IVA group element ions M(+) (M = Si, Ge, Sn and Pb) and benzene seeded in argon gas were studied. In addition to the association reaction pathway (forming [M(C(6)H(6))(x)](+), x = 1, 2, etc.), benzene was dissociated to form complex ions [M(C(5)H(5))](+), [M(C(7)H(5))](+) and [M(C(9)H(x))](+) (x = 5, 7 and 9), etc. DFT theoretical calculations indicated that, in the association products [M(C(6)H(6))](+), the M atom is close to one carbon atom of benzene, while in most of the dissociation complexes, pentagonal structures (M/cyclopentadienyl derivatives) were formed, with the M atom situated near the fivefold axis of the five-membered ring. The bond patterns in these complexes are discussed.
It has not been fully elucidated how endocrine-disrupting chemicals disrupt hormone functions or how strong their effects are compared with natural hormones. There is little information concerning the effects of tributyltin (TBT), one of the endocrine disrupters on living organisms. Although TBT at high concentration induced apoptosis in PC12 cells, TBT at low concentration inhibited the DNA fragmentation in the cells cultured in serum-free medium or in medium containing 6-hydroxydopamine. The cell viability grown in both medium conditions increased after treatment with TBT. These findings suggest that TBT exerted a apoptosis-inducing and -inhibiting effect. These diverse effect of TBT on apoptosis would cause serious damages on cell differentiation.
The earliest reports on the therapeutic use of metals or metal-containing compounds in cancer and leukemia date from the sixteenth and nineteenth centuries. They were forgotten until the 1960s, when the anti-tumour activity of the inorganic complex cis-diammine-dichloroplatinum(II) (cisplatin) was discovered. This led to the development of other types of non-organic cytostatic drugs. Cisplatin has developed into one of the most frequently used and most effective cytostatic drugs for the treatment of solid carcinomas. Numerous other metal compounds containing platinum, other platinum metals, and even non-platinum metals were then shown to be effective against tumours in man and experimental tumours in animals. These compounds comprise main-group metallic compounds of gallium, germanium, tin, and bismuth, early-transition metal complexes of titanium, vanadium, niobium, molybdenum, and rhenium, and late-transition metal complexes of ruthenium, rhodium, iridium, platinum, copper, and gold. Several platnium complexes and four non-platnium-metal antitumour agents have so far entered early clinical trials. Gallium trinitrate and spirogermanium have already passed phase II clinical studies and have shown limited cytostatic activity against certain human carcinomas and lymphomas. The two early-transition metal complexes budotitane and titanocene dichloride have just reached the end of phase I clinical trials and have been found to have an unusual pattern of organ toxicity in man. Titanocene dichloride will soon enter phase II clinical studies.
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