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Interaction of stannous chloride leads to alteration in DNA, triphosphate nucleotides and isolated bases.

Stannous chloride (SnCl2) is a reducing chemical agent used in several man-made products. SnCl2 can generate reactive oxygen species (ROS); therefore, studies have been carried out in order to better understand its damaging action in biological systems. In this work, calf thymus DNA, triphosphate nucleotides and isolated bases were incubated with SnCl2 and the results were analyzed through UV spectrophotometry. The presence of stannous ions altered the absorption spectra of all three isolates. The amount of stannous ions associated to DNA was measured by atomic absorption spectrophotometry. Data showed that more than 40% of the initial SnCl2 concentration was present in the samples. Our results are in accordance with the damaging potential of this salt and present evidence that stannous ions can complex with DNA, inducing ROS in its vicinity, which may be responsible for the observed lesions.

Animals↗

Acceleration by stannous ion of the evoked release of transmitter from motor nerve endings in the frog.

Stannous ion (Sn2+, 30 microM) increased the amplitude of endplate potential (EEP) in the frog sartorius muscle, although the amplitude of miniature endplate potential (MEPP) or acetylcholine potential evoked by iontophoretic application of acetylcholine was unchanged. Sn2+ (10-100 microM) dose-dependently increased the quantal content of the EPP. MEPP frequency was not altered by 30 microM Sn2+. These findings indicate that Sn2+ may increase the EPP as a result of acceleration of the transmitter release evoked by nerve impulses.

Acetylcholine↗

Tin(IV)-functionalised polymer supports; non-toxic and practical reagents for regioselective acetylation of sucrose.

Polymer-supported butyltin(IV) reagents have been surveyed for regioselectivity in acetylation of sucrose. Polymer-supported butyltin(IV) dichloride 8 catalysed the acetylation of sucrose to give a 59% yield of 6-O-acetyl sucrose 3, the precursor of sucralose. The yield is close to that of a previously reported process involving dibutyltin(IV) oxide (Bu2SnO). The spent polymeric resin could readily be regenerated and can be subsequently used in further synthetic reactions.

Acetylation↗

Stannous chloride-induced increase in calcium entry into motor nerve terminals of the frog.

The effects of SnCl2 on potentials recorded extracellularly from motor nerve terminals of the bullfrog were studied to elucidate the mechanism of the SnCl2-induced facilitation of evoked transmitter release. Under conditions in which the muscle preparations were pretreated with d-tubocurarine and tetraethylammonium in a K+-free medium, SnCl2 (50 microM) augmented the prolonged positive deflection ascribed to the inward Ca2+ current, an effect which was reduced by addition of Cd2+. The results suggest that SnCl2 could increase Ca2+ entry into the nerve terminals.

Action Potentials↗

Mean ionic charge on two components of technetium pyrophosphate prepared using stannous chloride.

Ionic charge, complexation equilibria, and acid-base equilibria can be measured at tracer concentrations by ion-exchange chromatography. To characterize better the principal components found in [99mTc]pyrophosphate preparations used for diagnostic bone and heart scanning, these were studied in two ion-exchange chromatographic systems: (A) DEAE-cellulose in pyrophosphate form at pH 6.0-7.5, and (B) DEAE-cellulose in perchlorate form at pH 3.7-4.8. The chromatographic retention times were measured as a function of pH and electrolyte concentration, and compared with those of trisoxalatochromium(III) complex, which was chosen as reference ion because of its similarity in charge and retention to the Tc-pyrophosphate complexes. The pyrophosphate complexes were even more sensitive to electrolyte concentration than was the triply negative reference ion: the calculated mean net charge in the mobile phase for the two principal Tc-pyrophosphate species were -4.5 +/- 0.5 and -4.9 +/- 0.5 at pH 4.3, and -11.2 +/- 1.3 and -10.1 +/- 1.0 at pH 7.0. It can be concluded that the two principal radioactive components in clinical Tc-pyrophosphate preparations both bear a high, pH-dependent negative charge.

Chromatography, Ion Exchange↗

Application of sodium stannite in the preparation of instant [99mTc]HIDA kit.

A rapid method for the production of freeze-dried kit containing 20 mg HIDA and 0.4 mg SnCl2 X 2H2O at pH 5.5-6.0 was developed using the stannite procedure. The Sn-HIDA ligand has been prepared successfully by dissolving HIDA in stannite solution without further pH adjustment. A gelchromatography column scanning (GCS) technique has been applied to study the chemical state of technetium in the preparation. The shelf-life of the freeze-dried powder of Sn-HIDA was found stable for at least 6 months as assessed by the GCS-technique. The hepatobiliary agent has a rapid blood clearance and is excreted predominantly by the hepatobiliary system. The biodistribution study in mice showed that more than 30% of the injected dose has been accumulated in liver at 5 min postinjection and at 30 min most of the injected activity has been passed to the intestine via the biliary system.

Animals↗

Factors affecting the labeling of human fibrinogen with 99mTc in vitro.

The preparation of [99mTc]fibrinogen is described. The following factors which could affect the quality of this preparation were studied: pH, SnCl2 and protein concentrations, pre- and post-labeling incubation times and labeling temperature. A 90% labeling yield was achieved by incubating fibrinogen with SnCl2 at pH 9.8 for 22 h before adding the TcO-4 solution. The product obtained was stable and was 85% clottable. The x-ray fluorescence technique was employed to measure the amount of bound tin at different times.

Fibrinogen↗

Sodium hypochlorite as a tissue solubilizing agent compatible with liquid scintillation counting.

The use of hypochlorite to prepare biological samples, containing incorporated radiolabeled molecules, for liquid scintillation counting was investigated. Hypochlorite both solubilized and decolorized a variety of animal tissues, but fat aggregates, cartilagenous tissue, and plant material resisted digestion. Although hypochlorite induced chemiluminescence, addition of acidified stannous chloride to the counting cocktail alleviated the spurious counts. The reported procedure, modified to suit particular experiments, may be applicable in a variety of situations where quantitation of biologically incorporated radiolabeled molecules is desired.

Animals↗

Effects of sputtered metal oxide films on the ceramic-to-metal bond.

The application of a thin oxide film is seen as a method of improving the ceramic-to-metal bond. Using sputter coating to form oxide films allows control of its thickness. The thickness of the oxide layer can also be controlled by sputter coating. Films produced by sputtering, in themselves, have superior bond strengths in that the high-energy levels that are used in the technique drive the coating material into the atomic lattice of the substrate material (dental gold). Remaining to be determined are optimum film thickness and the oxide to be used. However, the present study opens a field of study showing promise of improving porcelain-to-metal bonding in dental restoration.

Adhesiveness↗

Effect of hygiene instrumentation on titanium abutments: a scanning electron microscopy study.

Implant abutments can be exposed to a variety of oral prophylaxis procedures. In this in vitro study, titanium abutments were subjected to five oral prophylaxis treatment modalities; a metal scaler, a plastic scaler, a rubber cup, a rubber cup with tin oxide, and an air-powder abrasive. The abutment surfaces were then examined under both light and scanning electron microscopes. The metal scaler was seen to roughen the titanium surface. All other modalities tested appeared to smooth the titanium surface by removing surface debris and rounding off the sharp machined grooves present on the untreated abutment surface.

Air↗

Comparison of the adhesive strength of a BIS-GMA cement to tin-plated and non-tin-plated alloys.

This study compared the tensile bond strengths of two base metal alloys and two noble metal alloys, tin-plated and non-tin-plated, with an adhesive resinous cement. Two tin platers were compared for their effectiveness in enhancing the composite resin-to-metal bond. Cylinders of the alloys were bonded end to end with the adhesive cement, thermocycled for 24 hours, stored in distilled water for 27 days, and tested for tensile bond strength. The mean bond strengths and mode of failure were recorded, and scanning electron micrographs were recorded for subjective evaluation. Significant differences were demonstrated between the non-tin-plated and the tin-plated noble alloys and base metal alloys.

Adhesives↗

Tin salts prevent the plasma cell response to metallic tin in Lewis rats.

Inoculation of metallic tin powder produced marked proliferation of plasma cells and Russell body cells in draining lymph nodes. Prior, but not concurrent, administration of a soluble tin salt in the drinking water prevented the plasma cell hyperplasia. Various Na, Zn, Ag, and Cu salts were not inhibitory. The inhibitory effect of tin salts was detected as long as 2 months after the pretreatment was stopped. If the plasma cell response to metallic tin were due to an immunologic reaction, then the inhibition by a soluble tin salt may be a form of immunologic tolerance.

Animals↗

Effects of feeding stannous chloride on different parts of the gastrointestinal tract of the rat.

The effects of feeding inorganic tin on the gastrointestinal tract were examined in rats. Three groups of male weanling Wistar rats were fed a diet to which 0, 250, or 500 ppm Sn2+ had been added as SnCl2. A fourth group was subjected to feed restriction by pair feeding with the 500-ppm group. Comparison of the data from the tin-fed groups with both the control and the reduced diet groups allowed discrimination between effects of reduced feed intake and Sn2+ effects. Independent of the reduced feed intake, Sn2+ affected hemoglobin concentration in the blood and several small intestine parameters. Total length of the small intestine, as well as absolute and relative weights, was increased. An increase was also observed in the migration of epithelial cells along the villus, as revealed by [3H]thymidine incorporation and autoradiography in rats fed 900 ppm Sn2+ for 4 weeks. Stereo-light microscopy and scanning electron microscopy revealed the formation of ridge-like villi due to Sn2+ feeding and a decreased number of villi per unit surface. These data suggest that an increase in cell turnover in the small intestine, due to Sn2+, was responsible for these changes.

Animals↗

Some chemical aspects of labeling human fibrinogen with 99m-technetium.

Human fibrinogen was labeled with 99m-Technetium. Tin(II)-chloride in citric acid served as reducing agent for the pertechnetate-ion, eluted from a Mo-Tc-generator. Before adding the fibrinogen, the citric acid was always neutralized with sodium hydrogen carbonate. The influences on the quantity of fibrinogen bound 99m-Tc of the relative concentrations of Sn(II), fibrinogen and sodium hydrogen carbonate, of the reaction time and temperature were tested by thin-layer chromatography. The reaction temperature of 28 degrees C showed an optimum of fibrinogen bound 99m-Tc for the reaction time from 1 and 2 hours. With a reaction time of 30 minutes not enough 99m-Tc was bound to fibrinogen, the doubling of the reaction time from 1 to 2 hours showed only an increase of binding of less than 4%. The concentration of Sn(II) with respect to the fibrinogen concentration showed no influence on the quantity of fibrinogen bound 99m-Tc at low Sn(II)-concentrations. At values higher than 34 times of the fibrinogen concentration a decrease of the quantity of bound 99m-Tc was observed. The concentrations of sodium hydrogen carbonate showed no influence on the quantity of fibrinogen bound 99m-Tc but on the clottability of fibrinogen, the pH of the solution must be approximately 7.5. In 3 parallel and independent experiments under optimized conditions (1 hour at 28 degrees C, molar ratio of Sn(II) : fibrinogen = 8.5, pH = 7.5) 89.97 +/- 0.92 % of 99 m-Tc were bound to fibrinogen. Controls of these results by column chromatography showed a binding of 81.08 +/- 1.47 % of 99m-Tc to fibrinogen. The clottability of fibrinogen tested by the method of Clauss (1) was entirely preserved.

Bicarbonates↗