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PubMed1989

Toffee clearance and lingual sensory and motor activities in normal children and in children with articulation problems of speech.

The rate at which a standardized mouthful of toffee containing technetium (99mTc) tin colloid was cleared from the mouth during and after chewing was measured by counting the residual radioactivity in the mouth at short time intervals by external gamma counting. The clearance curve was resolved into three phases for each subject--chewing time (1), which coincided with the time to reach 10% of the initial counting rate, scavenging time (2), and a final slow diffusion phase (3). Although the mean chewing time was only 1.9 min, the technique allowed the pattern of clearance during this phase to be assessed for each of 10 normal children (mean age 11.1 yr) and 7 children (mean age 11.0 yr) diagnosed as having delayed articulation. Two measurements of sensory and motor functions of the tongue were made on the same subjects. These measurements were of oral stereognosis and tongue-tip manipulation. Within the control group, only the correlation between stereognosis error scores and the duration of phase 1 or phases 1 and 2 combined was statistically significant. The mean stereognosis and tongue manipulation scores were significantly lower in the poor articulation group than in normal children but, with one notable exception, the clearance curves were similar.

Adolescent↗
PubMed2000

Separation of metal chelates and organometallic compounds by SFC and SFE/GC.

Supercritical fluid chromatography (SFC) combines the high diffusion coefficients of gas chromatography (GC) and the solubility properties of liquid chromatography (LC). SFC generally requires lower temperatures for chromatographic separations and thus is more suitable for analyzing thermally labile compounds including a number of metal chelates and organometallic compounds. SFC also allows interfacing between supercritical fluid extraction (SFE) and chromatographic analysis of metal-containing compounds. A large number of metal chelates and organometallic compounds can be separated by SFC. This article summarizes SFC separation of various chelates of transition metals, heavy metals, lanthanides and actinides as well as organometallic compounds of lead, mercury, and tin reported in the recent literature. This article also discusses SFC detection systems and the determination of solubility of organometallic compounds by SFC.

Actinoid Series Elements↗
PubMed2002

A relative organolithium stability scale derived from tin-lithium exchange equilibria. Substituent effects on the stability of alpha-oxy- and alpha-aminoorganolithium compounds.

Quantitative thermodynamic stability scales of organolithium compounds can be derived from measurements of tin-lithium exchange equilibria. A DeltaG(eq) scale of alpha-oxy- and alpha-aminoorganolithium compounds was established, and quantitative stabilization effects of O-alkyl, O-alkoxyalkyl, O-carbamoyl, N-carbamoyl, and O-carbonyl groups of the alpha-carbanion are presented. It has been found that an alpha-oxycarbanion is far better stabilized by a carbonyl group as the O-substituent than by an alkyl or alkoxyalkyl group, while the anion-stabilizing effects of the different O-carbonyl substituents are comparable. An N-carbamoyl group was found to have a somewhat higher stabilizing effect than its O-carbamoyl counterpart. NMR data are presented that show that benzylic N- or O-substituted carbanions have highly planarized structures where the negative charge is highly delocalized. The stability data obtained from the tin-lithium exchanges can be easily converted into "effective pK" data that are useful for predicting the acid-base behavior of this type of organolithium species.

Journal Article↗
PubMed2000

Potassium sodium tin selenide, K3NaSn3Se8

The title compound, tripotassium sodium tritin octaselenide, K(3)NaSn(3)Se(8), has a molecular (zero-dimensional) structure containing trimeric [Sn(3)Se(8)](4-) units which consist of three edge-sharing SnSe(4) tetrahedra. The [Sn(3)Se(8)](4-) anions and the tetrahedrally coordinated Na(+) cations are arranged in an alternating fashion along the c axis to form SiS(2)-like chains, which are then separated by eight-coordinate K(+) cations. The Sn-Se bond distances are normal, being in the range 2.477 (1)-2.612 (1) A.

Journal Article↗
PubMed2002

Dichlorobis(pyridine-kappa N)bis(3,3,3-trifluoropropyl-kappa C(1))tin(IV).

In the title compound, [Sn(C(3)H(4)F(3))(2)Cl(2)(C(5)H(5)N)(2)], the Sn atom lies on an inversion centre and is octahedrally coordinated by two Cl atoms, two trifluoropropyl groups and two N atoms in an all-trans configuration. The electronegative trifluoropropyl groups increase the electrophilic properties of the Sn atom, and the Sn[bond]Cl and Sn[bond]N bonds are shortened in comparison with those reported for analogous compounds.

Journal Article↗
PubMed1976

Phase identification of dental amalgam using transmission electron microscopy.

Dental amalgam specimens were polished and afterward etched by an acid iodine solution. The replicas were obtained by the vacuum coating technique. The electron micrographs indicated that it was possible to identify the silver-mercury (gamma1) and tin-mercury (gamma2) intermetallic compounds formed during amalgam setting.

Dental Amalgam↗
PubMed2003

Germanium and tin analogues of alkynes and their reduction products.

The reduction of terphenylgermanium(II) or terphenyltin(II) chlorides with alkali metals was investigated. Treatment of Ar'GeCl or ArGeCl (Ar' = C(6)H(3)-2,6-Dipp(2), Dipp = C(6)H(3)-2,6-Pr(i)(2); Ar = C(6)H(3)-2,6-Trip(2), Trip = C(6)H(2)-2,4,6-Pr(i)(3)) with lithium, sodium, or potassium afforded the neutral alkyne analogues Ar'GeGeAr', 1, ArGeGeAr, 2, the singly reduced radical species NaArGeGeAr, 3, or KAr'GeGeAr', 4, or the doubly reduced compounds Li(2)Ar'GeGeAr', 5, Na(2)ArGeGeAr, 6, or K(2)ArGeGeAr, 7. Similarly, reduction of Ar'SnCl or ArSnCl afforded the neutral Ar'SnSnAr', 8, or ArSnSnAr, 9, the radical anions [(THF)(3)Na[rSnSnAr]], 10, [K(THF)(6)][Ar'SnSnAr'], 11, [K(THF)(6)][ArSnSnAr], 12, [K(18-crown-6)(THF)(2)] [ArSnSnAr], 13, or the doubly reduced Na(2)ArSnSnAr, 14, K(2)Ar'SnSnAr', 15, or K(2)ArSnSnAr, 16. The compounds were characterized by UV-vis, (1)H and (13)C NMR or EPR spectroscopy. The X-ray crystal structures of all compounds were determined except those of 2 and 9. The neutral 1 and 8 displayed planar, trans-bent CMMC (M = Ge and Sn) cores with M-M-C angles of 128.67(8) and 125.24(7) degrees, respectively. The M-M bond lengths, 2.2850(6) and 2.6675(4)A, indicated considerable multiple character and a bond order approaching two. Single and double reduction of the neutral species resulted in the narrowing of the M-M-C angles by ca. 12-32 degrees and changes in the Ge-Ge and Sn-Sn bond lengths. One-electron reduction afforded a slight (ca. 0.03-0.05A) lengthening of the Ge-Ge bonds in the case of germanium species 3 and 4 and a greater lengthening (ca. 0.13-0.15A) for the Sn-Sn bonds in the tin compounds 10-13. The addition of another electron yielded salts of the formal dianions [Ar'MMAr'](2)(-) and [ArMMAr](2)(-) which are isoelectronic to the corresponding doubly bonded, neutral arsenic and antimony derivatives. All the dianion salts were obtained as contact ion triples with two alkali metal cations complexed between aryl rings. The Ge-Ge bonds in the dianions of 5-7 were longer, whereas the Sn-Sn distances in the dianions in 14, 15, and 16 were shorter than those in the monoanions. Unusually, the Li(2)Ar'GeGeAr' salt, 5, displayed a longer Ge-Ge bond (by ca. 0.06A) than those of its Na(+) or K(+) analogue salts which was attributed to the greater polarizing power of Li(+). It was concluded that the M-M bond lengths in 3-7 and 10-16 are dependent on several factors that include M-M-C angle, Coulombic repulsion, alkali metal cation size, and the character of the molecular energy levels. The M-M bonding in the neutral compounds was accounted for in terms of a second-order Jahn-Teller mixing of sigma- and a pi-orbital which afforded bond orders near two for the neutral compounds, 1, 2, 8, and 9. Calculations on MeMMMe (M = Ge or Sn) model species showed that the LUMO corresponded to an orbital that had n(+) lone pair character. The slight Ge-Ge bond length increase upon one-electron reduction is consistent with these results, and the further bond lengthening upon double reduction is consistent with increased Coulombic repulsion. The greater Sn-Sn bond length increase seen for one-electron reduction of the tin species is probably due to the increased p-character of orbitals comprising the Sn-Sn sigma-bond when the Sn-Sn-C angle is decreased by ca. 30 degrees. Upon further reduction, the slight decrease in the Sn-Sn bond is probably a result of the reduced importance of Coulombic repulsion due to the larger size of tin and a widening of the Sn-Sn-C angles which may shorten the Sn-Sn sigma-bond.

Journal Article↗
PubMed2002

Synthesis and characterization of 2,6-Dipp(2)-H(3)C(6)SnSnC(6)H(3)-2,6-Dipp(2) (Dipp = C(6)H(3)-2,6-Pr(i)(2)): a tin analogue of an alkyne.

The reaction of Sn(Cl)C(6)H(3)-2,6-Dipp(2) (Dipp = C(6)H(3)-2,6-Pr(i)()(2)) with a stoichiometric amount of potassium in benzene affords 2,6-Pr(i)()(2)-H(3)C(6)SnSnC(6)H(3)-2,6-Pr(i)()(2) (1) as dark blue-green crystals. The compound 1 is a tin analogue of an alkyne. It was characterized by (1)H and (13)C NMR and UV-vis spectroscopy, cyclic voltammetry, combustion analysis and X-ray crystallography. The structural data show that 1 has a trans-bent, planar C(ipso)SnSnC(ipso) skeleton with a Sn-Sn bond distance of 2.6675(4) A and a Sn-Sn-C angle of 125.24(7) degrees. The Sn-Sn distance, which is ca. 0.15 A shorter than a conventional Sn-Sn single bond, and the trans-bent structure indicate the presence Sn-Sn multiple bond character unlike the related singly bonded ArPbPbAr species.

Journal Article↗
PubMed1997

In vitro lymphocyte proliferation test in the diagnosis of oral mucosal hypersensitivity reactions to dental amalgam.

Patch testing was carried out in 23 patients with oral lichenoid lesions (OLL) topographically related to dental amalgam fillings. Twelve patients displayed positive reactions to several mercury compounds, whereas 11 patients were negative. An in vitro lymphocyte proliferation (LyPro) test was carried out using different mercury compounds and other metal salts. Mercuric chloride and phenyl mercuric acetate caused positive proliferation in 3/12 patch test-positive and in 5/11 negative patients. One out of seven healthy control subjects had a positive LyPro result. The mean stimulation index (SI) values between the patient groups or compared with the control subjects did not differ significantly. Zinc, tin, copper or silver salts caused in vitro lymphocyte stimulation in most of the patients and in healthy control people. Total (14) or partial (4) replacement of amalgam fillings was carried out in 18 patients. Complete healing of lichenoid lesions was seen in 4/6 LyPro test-positive and in 5/10 patch test-positive patients at follow-up examinations 12 months after the replacement of amalgam fillings. The in vitro proliferation assay seems not to be a specific test for identifying the patients who would benefit from amalgam replacement.

Adult↗
PubMed1991

Comparative photoactivity of tin and zinc porphyrin inhibitors of heme oxygenase: pronounced photolability of the zinc compounds.

Metalloporphyrin inhibitors of heme oxygenase may also have photosensitizing properties in vivo. To assess photoactivity in serum, the relative ability to mediate photooxidation of tryptophan or other oxidizable targets, presumably by singlet oxygen production, was measured for tin mesoporphyrin, zinc mesoporphyrin, and zinc deuteroporphyrin bisglycol in aqueous solution and when bound to human serum albumin. While tin mesoporphyrin sensitized at the greatest initial rate in aqueous solution, the zinc compounds sensitized at a greater initial rate in detergent micelles or when bound to albumin. There was minimal alteration of the tin mesoporphyrin during the time course of illumination in the Soret or visible absorption regions. The zinc compounds, however, proved to be extremely photolabile and were extensively destroyed by light; the photooxidized forms were found to be ineffective as inhibitors of heme oxygenase.

Animals↗
PubMed1987

Organotin-induced hemolysis, shape transformation and intramembranous aggregates in human erythrocytes.

Organotin compounds examined in this study exhibited a relative order of potency for induction of in vitro hemolysis in human erythrocytes as follows: tri-n-butyltin greater than tri-n-propyltin greater than tetra-n-butyltin greater than triphenyltin chloride greater than tri-n-ethyltin bromide greater than dibutyltin dichloride greater than stannous chloride greater than tri-n-methyltin chloride = butyltin chloride dihydroxide. All of the organotin compounds induced erythrocyte shape transformation from the normal discocyte to an echinocyte and, in addition, triphenyltin chloride, tetra-n-butyltin and tri-n-ethyltin bromide also elicited stomatocyte formation at higher concentrations. Select organotin compounds also formed tin-containing aggregates within the plasma membrane. The relative order of effectiveness for organotin induction of intramembranous aggregates was tri-n-butyltin greater than tri-n-propyltin greater than tetra-n-butyltin greater than tri-n-ethyltin bromide, which was based upon the lowest concentration at which they were observed. These results support the previously suggested theory that organotins are membrane effectors because of their comparatively high hydrophobic, lipid partitioning properties. The relatively lipophilic compound, triphenyltin chloride, appeared to be anomalous because it did not readily promote hemolysis or induce the formation of intramembranous aggregates in human erythrocytes. A log-linear statistical model demonstrated an association of hemolysis with both tri-n-butyltin aggregate formation and shape transformation. Select organotin compounds should be useful probes in membrane studies because of their numerous effects.

Erythrocyte Aggregation↗
PubMedDate not supplied

Comparative organotin toxicity in the developing rat: somatic and morphological changes and relationship to accumulation of total tin.

The effect of the structure of organotin compounds on their toxicity and neurotoxicity to the developing rat has been studied. Oral administration was used after selection of a vehicle that gave uniform organotin solubilization as evidenced by toxicity and chemical solubility data. This vehicle was milk plus Tween-80. Eight different organotin compounds were systematically surveyed for effects in the neonatal rat. Trimethyl- and triethyltin were most toxic, and were somewhat more toxic than tri-n-propyltin. Tri-n-butyltin was somewhat less toxic, while tricyclohexyl-, triphenyl-, diethyl- and dimethyltin were least toxic. Some higher doses of trimethyl- or triethyltin caused neuropathological changes that were characteristic for each compound, these changes being absent for the other agents. Regardless of their toxicity, significant amounts of tin, as the element, were found in brain, kidney, and liver after treatment with all agents. However, detectable blood values were only obtained for trimethyl- and triethyltin.

Administration, Oral↗
PubMed1981

A subacute toxicity study on 99m Tc stannous Glucoheptonate injection.

A subacute toxicity study on 99m Tc stannous glucoheptonate was performed with rats, dogs and rabbits, injected intravenously at ten to 100 times the human dose on a body weight basis. There were no abnormalities in the clinical status of any of the animals. No changes were found in urinalysis, blood chemistry or hematology in the rabbit nor in gross examination, renal histology or bone marrow smears in the rats and rabbits. Hepatic histology was also done. A focal area of necrosis in a liver of one rabbit that had been injected with 100 times the human dose was observed using light microscopy. Examination by electron microscopy in another group of rats and rabbits was prompted by the observation of that lesion. This revealed vacuolated and dilated smooth endoplasmic reticulum and degranulated and vesiculated rough endoplasmic reticulum in all the test livers. X-ray microanalysis indicates that the ultrastructural changes are linked to the deposition of tin.

Animals↗
PubMed2005

Metal-mediated entry to functionalized 3-substituted 3-hydroxyindolin-2-ones via regiocontrolled carbonylallylation, bromoallylation, 1,3-butadien-2-ylation, propargylation, or allenylation reactions of isatins in aqueous media.

Reactions of 2,3-indolinediones (isatins) with stabilized organometallic reagents were investigated in aqueous media. Isatins and a variety of stabilized organic halides undergo coupling under Barbier-type conditions in the presence of different metals (indium, tin, zinc) and additives (ammonium chloride, hydrobromic acid, bismuth(III) chloride, hafnium(IV) chloride). The regiochemistry of the processes (carbonylallylation, bromoallylation, 1,3-butadien-2-ylation, propargylation, or allenylation reactions) were generally excellent. On this basis, simple and fast protocols for the synthesis of the potentially bioactive 3-substituted 3-hydroxyoxindole moiety were developed.

Allyl Compounds↗
PubMed1985

Detoxification of the estertin stabilizer bis-(beta-carbobutoxyethyl)tin dichloride in rats by hydrolysis of the ester bond.

In a previous comparative toxicity study with alkyltin and estertin stabilizers, it was recognized that estertin compounds displayed in vitro lymphocytotoxic effects comparable to the dialkyltin compounds, but did not induce lymphoid atrophy when administered in vivo to rats as was found for the dialkyltin compounds. This discrepancy between the in vitro and in vivo toxicity of estertin compounds prompted us to study the metabolism of the estertin compound bis-(beta-carbobutoxyethyl)tin dichloride (CBETC) in rats. The hydrolysis product bis-(beta-carboxyethyl)tin dichloride (CETC) was the only metabolite detectable using TLC. After daily intravenous administration of 20 mg CBETC/kg body weight CETC was detected in urine only, whereas no faecal excretion of organotin was found. Intravenous administration of relatively large amounts of 20 mg CETC/kg body weight indicated that this compound is not metabolized but rapidly excreted in urine, probably because of its hydrophilic nature. Daily gavage of 15 mg CBETC/kg body weight resulted in the excretion of appreciable amounts of CETC in urine, but CETC was also found in faeces together with the parent compound. In the gastrointestinal tract CETC would be formed locally probably by acid hydrolysis of CBETC as was shown also in vitro in acidified water. Esterases in the gastrointestinal tract, tissues and blood might also be responsible for the fast hydrolysis of CBETC. As shown in our previous study the hydrolysis product CETC did not cause any lymphocytotoxic effect. Therefore we conclude that in the rat the estertin compound CBETC is effectively detoxified by hydrolysis of the ester bond.

Administration, Oral↗