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[Modified biological behaviour of 99mTc-pertechnetate in man as a result of a preceeding administration of tin (tin effect) (author's transl)].

An increased image of blood-filled spaces (Plexus choriodeus, Sinus transversus) was observed in 99mTc-pertechnetate scintigraphy when it had been preceded by the administration of tin (e.g. of 99mTc-Sn-diphosphonate). We have called this behaviour the "tin effect". In vitro studies demonstrated binding of about 80% of the administered activity in the blood with a biological half-life of about 44 hr and an effective half-life of about 5.3 hr. 95% of the blood activity was bound to red cells and 5% to plasma. This resulted in an increased radiation dose to the bone marrow of about 530 mrad/mCi 99mTc-pertechnetate (following tin). The extent of the tin effect decreased with the length of the interval between tin and 99mTc-pertechnetate administration. Because of the tin effect 99mTc-DTPA or 99mTc-citrate should be used for brain scintigraphy if this has to be performed within the first 5 or 7 days following a bone scintigraphy with a tin-containing radiopharmaceutical. The "tin effect" might be taken advantages of when labelling red cells and imaging vascular spaces.

Brain

[Effect of tin on rats. 1. Inverse voltammetric determination of tin in the presence of lead in biological material after extraction].

By means of inverse polarography, the authors determined tin selectively after double extraction with diethylammonium diethyl dithiocarbamate (DADDTC) in perchloric solution. The recovery rates were: in potatoes, 91.7 +/- 5.8%; in beef kidney, 85.0 +/- 22.7%; in beef liver 79.9 +/- 13.8%; and in milk, 69.8 +/- 11.4%. Possible interferences from other elements with the tin determination are discussed.

Animals

[Clinical and microstructural comparative studies on fillings made from gallium-tin-nickel alloys and from silver-tin amalgam].

The filling material "Gallodent" has been clinically controlled for a period of one year. Scanning electron microscopic examinnations revealed greater surface porosity with negligible microleakage and better marginal adaptation as compared to amalgam. Early corrosion phenomena required re-polishing every three months. This disadvantage and the brittleness of the gallium-tin-nickel alloys hinder, at present, these alloys from superseding high-silver amalgams.

Dental Amalgam

Studies on energy-linked reactions: isolation, characterisation and genetic analysis of trialkyl-tin-resistant mutants of Saccharomyces cerevisiae.

Mutants of Saccharomyces cerevisiae resistant to triethyl tin sulphate have been isolated and are cross-resistant to other trialkyl tin salts. Triethyl-tin-resistant mutants fall into two general phenotypic classes: class 1 and class 2. Class 1 mutants are cross-resistant to a variety of inhibitors and uncoupling agents which affect mitochondrial membranes (oligomycin, ossamycin, valinomycin, antimycin, erythromycin, chloramphenicol, '1799', tetrachlorotrifluoromethyl benzimidazole carbonylcyanide-m-chlorophenylhydrazone and cycloheximide). Class 2 mutants are specifically resistant to trithyl tin and the uncoupling agent "1799' [bis-(hexafluoroacetonyl)-acetone]. Triethyl tin at neutral pH values is a specific inhibitor of mitochondrial energy conservation reactions and prevents growth on oxidisable substrates such as glycerol and ethanol. Triethyl-tin-resistant mutants grow normally on glucose and ethanol in the presence of triethyl tin (10 muM). Biochemical studies indicate that the mutation involves a modification of the triethyl tin binding site on the mitochondrial inner membrane, probably the ATP-synthetase complex. Triethyl tin resistance/sensitivity in yeast is determined by cytoplasmic (mitochondrial) and nuclear genes. The mutants fall into a nuclear and a cytoplasmic (mitochondrial) class corresponding to the phenotypic cross-resistance classes 1 and 2. In the cytoplasmic mutants the triethyl tin resistance segregates mitotically and the resistance determinat is deleted by the action of ethidium bromide during petite induction. Recombination studies indicate that the triethyl tin mutations are not allelic with the other mitochondrial mutations at the loci RI, RIII and OLI. This indicates that the binding or inhibitory sites of oligomycin and triethyl tin are not identical and that the triethyl tin binding site is located on a different mitochondrial gene product to those which are involved in oligomycin binding. Interaction and cooperative effects between different binding sites on the mitochondrial inner membrane have been demonstrated in studies of the effect of the insertion of the TETr phenotype into mitochondrial oligomycin-resistant mutants and provide an experimental basis for complementation studies at the ATP-synthetase level.

Adenosine Triphosphatases

Toxicologic studies of tin needles at the intrathoracic site of mice.

Male Marsh mice which received a single intrathoracic injection of 4 mg of tin needles at 3 months of age were compared with controls given isotonic saline. The form and size of most of the tin needles were similar to those of asbestos needles which produced mesotheliomas and lung neoplasms in rodents. Water and food intake was markedly reduced for 24 hrs after the injection of tin. Survival rates (followed for 19 months), pathology of the bladder, liver, and kidney, as well as local and general cancer development were not adversely associated with the tin treatment as compared with the tin treatment as compared with controls. The local reaction to the tin included giant cell phagocytosis, nodular fibroplasia, and capillary formation. The failure of the tin needles to induce local neoplasms may relate to their high density as compared with silicates and/or their lack of the unique potential of the silicate particles to stimulate avascular fibrosis.

Animals

5-aminolevulinate dehydratase activity in blood of rabbits given tin or lead.

The activity of 5-aminolevulinate dehydratase (ALAD) in rabbit blood is significantly inhibited by tin. Intravenous administration of tin (0.48 or 4.8 mumol/kg body weight) causes a decrease in the activity of the enzyme by 60% or 94% respectively. The effects of tin and lead on ALAD differ: inhibition by tin is not affected by pre-incubation at 50-60 degrees C, whereas the inhibitory effect of lead is increased by the same pretreatment. The optimum pH for rabbit blood ALAD is 6.8 in control rabbits. This optimum shifts to pH 5.8-6.0 in the blood of tin-treated rabbits, with or without pre-incubation at 60 degrees C for 5 min, while a similar shift is prevented by the same pre-incubation after lead treatment. Recovery to normal activity is faster after tin than after lead treatment.

Animals

Complexing of reduced technetium and tin(II) by chelating phosphate compounds. II. In vitro stability of pyrophosphate and ethane-1, hydroxy-1, diphosphonate (EHDP) complexes.

The in vitro stability of 99mTc- and 113Sn-pyrophosphate and ethane-1, hydroxy-1, diphosphonate (EHDP) complexes was studied by varying the mode of preparation. The 1-hr distribution in the rat was used as an indicator for complex formation or destruction. A maximum of bone uptake and urinary excretion and a minimum of soft tissue concentration was obtained if there was an excess of phosphate in relation to tin(II) in the equilibrium. Formation of tin(II) colloid was favoured in the presence of an excess of tin(II) in the equilibrium, 99mTc colloid occurred with some delay. After dilution in neutral normal saline the chelates were more or less destroyed, as shown by a 113Sn(II) colloid formation whereas the 99mTc-phosphate complexes were transformed into a 99mTc kidney agent. At pH 11 the 113Sn(II)-phosphate complexes proved to be stable, the 99mTc-phosphate complexes were also transformed into the 99mTc kidney agent. Oxidation of all tin(II) in the equilibrium by hydrogen peroxide did not change the distribution patterns of 113Sn, 99mTc was oxidized to pertechnetate. In general complexes between tin(II) and chelating phosphate compounds proved to be more stable than those with reduced technetium. EHDP was found to form stronger complexes with tin(II) and reduced technetium than pyrophosphate.

Animals

Uremic hyperstannum: elevated tissue tin levels associated with uremia.

Previous work has shown that the concentration of the essential trace element tin is elevated in several tissues of dialyzed uremic patients. Analysis of 80 postmortem liver samples from controls and nondialyzed uremic and dialyzed uremic patients now shows that nondialyzed uremic patients also have abnormally high tin concentrations, averaging about three times that of controls. It is concluded that these elevated tin levels are associated with uremia rather than with dialysis. Abnormally high tin levels were also found in the kidneys of uremic patients at autopsy. This may have special importance, since tin has been shown to be a powerful inducer of heme oxygenase activity in rat kidney. The urinary excretion of tin by nondialysed uremic patients was measured and found to be normal.

Adult

Tin-protein binding kinetics in normal and uremic plasma and its effect on dialysis fluxes.

A high affinity of plasma protein for tin has been demonstrated by ultrafiltration studies. At physiologic concentrations, UF/P remained below 1%, consistent with more than 99% binding. Binding of tin was nearly complete despite a decrease in plasma protein concentration to 3.5 Gm% and an increase in plasma tin by 80 mg/L. This binding inhibits efflux of tin from plasma during dialysis while influx occurs readily. This may be a mechanism for accumulation of tin in patients undergoing maintenance hemodialysis. A mechanism for tin chelation could be clinically beneficial in the syndrome of dialysis dementia.

Blood Proteins

The chloride transport induced by triaklyl-tin compound across erythrocyte membrane.

The effect of tripropyl-tin chloride on anion permeability was studied using red cells previously treated with a covalent binding inhibitor 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) to inhibit completely and irreversibly the natural anion transport system. It was demonstrated that the tin compound can mediate chloride-hydroxide and chloride-chloride exchanges across the "impermeabilised" erythrocyte membrane. In the non hemolytic range, the rate of exchange increased with the concentration of the tin compound in a non linear fashion, and no saturation effect was seen. The temperature profile of the chloride self exchange induced by tripropyl-tin was studied and the apparent activation energy found was 29 Kcal/mol. The tripropyl-tin chloride cannot mediate a chloride-bicarbonate exchange. Because of this discriminatory effect between hydroxide and bicarbonate, the tin compound can be useful in certain experimental conditions as seen for the study of the anion "carrier" of the red cell membrane ("cousin, J.L., Motais, R. and Sola, F. (1975) J. Physiol. Lond. 253, 385-399).

Bicarbonates

[Square-wave polarographic determination of tin in products of the food processing industry].

A square-wave polarographic method suitable for measuring tin in canned products and raw materials for food industry was examined. After wet digestion of the sample tin was directly determined from the acidic stock solution gained. If 10 ml of the stock solution was equivalent to 1 g sample,--varying sensitivity of the instrument--tin could be determined in the range of 5 micrograms/g--400 micrograms/g with +/- 5% relative error. By increasing sensitivity of the instrument this range could be extended to as little as 0,5 micrograms tin/g sample. The optimal quantity of hydrochloric acid to be added to the sulphuric acid solution of the digested sample before the instrumental measurement was determined by means of model solutions. Examinations concerning interference of lead were also performed. It is established, that if the ratio of Sn/Pb is at least 4/1, lead does not interfere with the polarographic tin determination. If the ratio of Sn/Pb is 2/1 or 1/1 tin content can be calculated after measuring the height of the peak of lead in sulphuric acid electrolyte. The method was applied for several canned products and comparative tests were performed with the spectrophotometric method given in the Hungarian standard MSZ 3612/7-77.

Animals

The effect of iron, tin, aluminium, and chromium on fading, discoloration, and precipitation in berry and red beet juices.

The effect of iron(II), tin(II), aluminium(III), and chromium(III) on the properties of red whortleberry, blackcurrant, and red beet juices was followed during storage for 10 months at 5 degrees C. The colour and pH changes were studied, and the precipitates formed were weighed and their metal contents assayed. Of the metals tested, only tin caused bluish discoloration in the berry juices. In the case of iron, aluminium, and chromium the low pH prevented this type of discoloration. In berry juices, some increases in colour intensity took place with the lowering of pH value, whereas in red beet juice the opposite change occurred. The colour changes due to storage appear to take place irrespective of the metals. Precipitation is enhanced in red whortleberry juice only by tin, and in blackcurrant juice by tin and iron. In red beet juice, precipitation is increased by the lowering of pH resulting from metal salt addition. In general, increase in the amount of metal added increased the metal content of the precipitate. Iron showed the greatest tendency to become bound in the precipitate, particularly in blackcurrant and red beet juice. The suitabilities of the metals for canning purposes are considered. Chromium, in particular, has interesting possibilities in view of the low degree of colour change associated with it.

Aluminum

On the vanadium and tin contents of diet and human blood.

The vanadium and tin contents of total diet samples collected in five Italian towns are given, and discussed in relation to literature data, their status as essential elements and their levels in human blood. Tin in blood was found to be below 2 ng ml-1 in a group of 14 subjects, and barely detectable even after oral consumption of 60 mg of tin.

Animals

[Nutritional and toxicological impacts of administered inorganic tin for six months in rats (author's transl)].

An experimentation of intoxication by stannous chloride has been realized in the rat. Two groups of animals have been fed ad libitum, during six months, with a diet containing respectively 0,4 and 0,8 g of tin (SnCl2) for 100 g of dry food. By gamma radioactivity measurements (with 113Sn used as a tracer), it results that this metal does not practically clear the digestive barrier. All the treated animals are characterized by a ponderal evolution obviously lower than temoins. At the end of treatment, tin entails a significative diminution of hematocrit, hemoglobin and serous iron, particularly at the highest dose studied. The essential impact remains that tin induces a total irritation of gastro-intestinal tract, proved by histological investigations.

Animals

[Peculiarities of alkyl tin effects on respiration and oxidative phosphorylation of rat liver mitochondria].

Electron transfer and oxidative phosphorylation were studied as affected by tinalkyls. It is shown that all of them inhibit effectively respiration of the rat liver mitochondria. The action of bis(tributyl tin)oxide and dibutyl diisooctyl thioglycolate tin on the mitochondria in a state of dissociation is localized in the terminal step of the respiration chain. The other alkyls act in the site located before cytocrome c. The effect of bis (tributyl tin) oxide on both the ADP-activated respiration and DNP-activated ATPase of intact mitochondria is similar to that of oligomycin. These effects might be explained by the presence two electrophilic centres in a molecule of this compound.

Adenosine Diphosphate

Effect of temperature of SnF2 solution on tin and fluoride uptake by bovine enamel.

The tin and fluoride concentrations in surface layers of intact enamel specimens were analytically determined after treatment with 8% SnF2 solutions at temperatures of 25, 45, 65, and 85 C. Significant increases in fluoride uptake and particularly tin uptake in enamel correlated directly with the temperature of the SnF2 treatment.

Acid Etching, Dental