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At least 19 recordsLinked to original sources
PubMed1989

Flow cytometric comparison of the effects of trialkyltins on the murine erythroleukemic cell.

Cellular effects of exposure to tributyltin (TBT), triethyltin (TET), or trimethyltin (TMT) were investigated by flow cytometry employing the murine erythroleukemic cell (MELC) as a model cellular system. Cell viability was investigated by the carboxyfluorescein diacetate (CFDA) uptake/propidium iodide (PI) exclusion method: above a critical concentration (exposure for 4 h), which was specific for each of the trialkyltin compounds, the cell becomes permeable to PI, indicating loss of viability. Cellular CF fluorescence (derived from intracellular hydrolysis of CFDA) increased as a function of alkyltin concentration below the critical concentration and decreased as viability decreased above the critical concentration. Relative membrane potential, monitored with a cyanine dye (DiOC6), correlated with viability (PI exclusion), remaining essentially unaltered below the critical concentration and decreasing above it. At/above 1 microM TBT, 5 microM TET, or 100 microM TMT, the cell cycle was blocked in the G2/M phase. The 90 degrees light scatter (a measure of refractive index), axial light loss (a measure of volume), and fluorescein isothiocyanate (FITC) fluorescence (a measure of protein content) of nuclei isolated from trialkyltin-treated MELC by detergent treatment, increased as a function of organotin dose. Fluorescence and interference microscopy revealed increased quantities of residual cytoplasmic tags adherent to the nuclei as a function of organotin dose, apparently resulting from increased cytoplasmic resistance to detergent-mediated solubilization. The effects of the trialkyltins correlated with their lipophilicity (octanol/water coefficient). These data support the hypothesis that fixation (protein denaturation, cross-linking, etc.) is an important mode of organotin cytotoxicity.

Animals↗
PubMed1990

Electrically silent anion transport through bilayer lipid membrane induced by tributyltin and triethyllead.

The method of the measurement of the nonelectrogenic fluxes of hydrogen (or hydroxyl) ions (JH) based on the local proton gradients formation in the unstirred layers near a bilayer lipid membrane (BLM) is applied for recording the nonelectrogenic anion/OH- exchange on BLM induced by tributyltin (TBT) and a novel carrier (Hager, A., Moser, I., & Berthold, W. 1987. Z. Naturforsch., 42C:1116-1120), triethyllead (TEL). This method has been used previously for measuring the cation fluxes through BLM. TBT and TEL are shown to be equally efficient in the induction of Cl-/OH- exchange. JH induced by TBT is constant at 4 less than pH less than 7. JH decreases at pH less than 4 and pH greater than 7. Both ionophores have a transport sequence: I- greater than Br- greater than Cl- greater than F-. The quantitative measurements reveal that TEL better discriminates these four anions than TBT. It is concluded that this method may prove helpful in a search and study of anion/OH(-)-exchangers isolated from natural membranes.

Anions↗
PubMed1991

Organotin compounds induce aneuploidy in human peripheral lymphocytes in vitro.

In vitro exposure of PHA-stimulated human lymphocytes to organotin compounds resulted in statistically significant increases in the frequencies of hyperdiploid cells. When taken together with our previous study demonstrating spindle inhibiting effects of the same organotin compounds by an indirect method (Jensen et al., 1989), the present study strongly indicates that organotin compounds are able to induce aneuploidy, probably by affecting spindle function.

Adult↗
PubMed1991

Acute ototoxicity of trialkyltins in the guinea pig.

Two trialkyltin compounds, trimethyltin chloride (TMT) and triethyltin bromide (TET) were evaluated for their acute effects on cochlear function in pigmented guinea pigs. Compound action potential (CAP) thresholds and 1 microV RMS cochlear microphonic (CM) isopotential curves were generated for 25 subjects following ip injection of TMT (2 mg/kg), TET (12 or 24 mg/kg) or inert vehicle (0.9% saline or 15% ethanol). The CAP is generated by the release of neurotransmitters from the inner hair cells and the subsequent depolarization of spiral ganglion cells. However, the sensitivity of the CAP is influenced by other cochlear structures including the outer hair cells which are thought to influence sensitivity of the inner hair cells. By contrast, CM reflects electromechanical function of the outer hair cells. CAP function was severely disrupted by organotin exposure while CM was unaffected by these agents. TMT administration impaired CAP thresholds at all frequencies within 30 min of administration. Thresholds deteriorated slightly more between 30 and 60 min. TET also reduced the sensitivity of the CAP to all frequencies. At the lower dose moderate impairments of function were observed at 30 min which became more noticeable at 60 min. Following 24 mg/kg TET injection, CAP sensitivity was markedly impaired even at 30 min. The CM isopotential values were not significantly altered 30 min or 60 min after either TMT or TET treatment at any of the 11 frequencies tested. These data document far more rapid toxic effects of TMT and TET than have been seen in most intact neuronal systems. They indicate that both organotins initially disrupt the functional integrity of either inner hair cells or spiral ganglion cells within the cochlea such that depolarization occurs only following a significant increase in stimulus intensity.

Action Potentials↗
PubMed1992

Inhibition of human lymphocyte coproporphyrinogen oxidase activity by metals, bilirubin and haemin.

Coproporphyrinogen III oxidase activity in human lymphocytes was found to be inhibited by cadmium and mercury but not by lead. The organo-metal compounds tributyltin and methylmercury were effective inhibitors of this haem biosynthetic pathway enzyme. Haemin (the ultimate product of the pathway) and bilirubin (a product of haem catabolism) were also shown to be inhibitory. Kinetic studies performed under initial velocity conditions showed that bilirubin was a non-competitive inhibitor and that one bilirubin molecule was bound to both the enzyme and enzyme substrate complex. The analysis also showed haemin to be a non-competitive inhibitor in which two haemin molecules bind to the enzyme whereas the enzyme substrate complex accepts only one haemin molecule. The possible physiological significance of the inhibition of coproporphyrinogen III oxidase activity by haemin and bilirubin is discussed.

Bilirubin↗
PubMed1992

The effect of tributyltin chloride on vascular responses to atrial natriuretic peptide.

The effects of tributylin chloride (TBT) on vascular smooth muscle responses to norepinephrine, nitroprusside (SNP) and atrial natriuretic peptide (ANP) were studied in isolated aortic rings of rats. TBT did not interfere with norepinephrine-induced contraction or SNP-induced vasorelaxation. However, TBT produced a dose-dependent inhibition of ANP-induced vasorelaxation. Inhibition was not observed with inorganic tin chloride, SnCl2. The inhibition of vasorelaxation was accompanied by a parallel inhibition of ANP-induced cGMP generation. SNP-induced generation of cGMP was not affected by TBT. TBT did not interfere with binding of ANP to its receptor in bovine adrenal glands suggesting that the effects of TBT were mediated by direct interaction with membrane-bound guanylate cyclase.

Animals↗
PubMed1991

Pattern of organotin inhibition of methanogenic bacteria.

Seven organotin compounds and tin chloride were tested for their effects on the methanogenic bacteria Methanococcus thermolithotrophicus, Methanococcus deltae delta LH, and Methanosarcina barkeri 227. The methanogens were strongly inhibited by triethyltin, tripropyltin, and monophenyltin compounds, generally at concentrations below 0.05 mM. Less inhibition by tributyltin and diphenyltin was observed at levels below 0.1 mM, but complete inhibition was observed at a 1 mM concentration. Tin chloride inhibited all methanogens, with nearly complete inhibition at a 1 mM concentration. There was no inhibition by tetra-n-butyltin and triphenyltin compounds even at 2 mM, the highest concentration tested. The 50 and 100% inhibitory concentrations of all compounds were estimated; these values varied with both the compound tested and the bacterium tested. The 50% inhibitory concentration estimate generally decreased (i.e., giving a higher toxicity) as the total surface area of the alkyltin molecules decreased. These results differ considerably from those reported previously for aerobic microorganisms (G. Eng, E. J. Tierney, J. M. Bellama, and F. E. Brinckman, Appl. Organometallic Chem. 2:171-175, 1988), where a clear correlation between increasing total molecular surface area and increasing toxicity was documented with a variety of organisms. Using the same procedures as for the methanogens, we examined the effects of organotin compounds on Escherichia coli growing aerobically or anaerobically. The E. coli inhibition pattern clearly resembled that seen in the data of Eng et al., under both aerobic and anaerobic conditions.

Escherichia coli↗
PubMed1991

Accumulation of tri-n-butyltin chloride and triphenyltin chloride by oral and via gill intake of goldfish (Carassius auratus).

1. The bioconcentration factors (BCF) of both chemicals via gill intake of goldfish reached plateaux after 21 days of exposure. The average BCF values of Bu3SnCl and Ph3SnCl (N = 2) were 1976 and 1384, respectively, after 21-28 days of exposure. 2. The BCF values by oral intake of goldfish reached plateaux after 28 days for Bu3SnCl but did not for Ph3SnCl. The BCF values of Bu3SnCl and Ph3SnCl were 0.04 and 0.10, respectively, after 35 days. 3. The order of the BCF values via gill intake was reversed compared with that by oral intake. Further, the contamination of freshwater fish by these compounds was discussed using the results of these experiments.

Administration, Oral↗
PubMed1989

Effect of tributyltin on Escherichia coli: role of modifying factors.

The effects of inorganic and organic tin compounds and various factors affecting the toxicity of the latter to Escherichia coli were studied. In comparison to stannous chloride, tributyltin chloride (TBTC) was more inhibitory to the growth of the test organism; this may be due to its greater liposolubility and ready absorption through the bacterial membrane. The toxicity of TBTC to E. coli was modulated by various factors, such as pH, sulfate and chloride ions, and the presence of glucose, succinate, and reducing agents like cysteine and dithiothreitol (DTT). TBTC was more toxic to cells in minimal than in complex media. Similarly, this compound was more inhibitory to the growth of E. coli at acid pH than at basic pH. Succinate in contrast to glucose, when used as a carbon source, made the bacterium more sensitive to TBTC. Cysteine and DTT (both at a final concentration of 0.5 mM) partially protected the cells against the inhibitory effect of this agent.

Chlorides↗
PubMed1979

Effect of organotin compounds and hexachlorophene on brain adenosine cyclic 3',5'-monophosphate metabolism.

The effect of triethyltin (TET), triphenyltin (TPT), hexachlorophene (HCP) and cuprizone on adenosine cyclic 3',5'-monophosphate (cyclic AMP) production in rat brain was examined both in vitro and in vivo. TET and TPT inhibited basal adenylate cyclase activity of brain homogenate at a concentration as low as 1 microM in vitro but these compounds had no effect on norepinephrine (NE) and dopamine(DA)-stimluated enzyme activity. HCP and cuprizone failed to inhibit adenylate cyclase activity. In vivo TET given intravenously at a dose rate of 10 mg/kg decreased the cyclic AMP content of cerebrum, but not of medulla. TPT and HCP give intravenously and intraperitoneally respectively failed to decrease the cyclic AMP content of the cerebrum. In the case of TET the reduction in cyclic AMP content of the cerebrum was prevented by maintaining the rats normothermic after treatment. On the basis of these results the inhibition of adenylate cyclase produced by TET in brain homogenates in vitro would not appear to be involved in the development of nervous changes associated with acute TET toxicity, or in the production of progressive brain oedema caused by TET, HCP and cuprizone.

Adenylyl Cyclases↗
PubMed1991

Analysis of organotin uptake in Escherichia coli K-12.

The effect of tributyltin chloride (TBT) was potentiated by the presence of Tris ions in the growth medium compared with phosphate ions. The growth of Escherichia coli in the presence of Tris ions was inhibited completely at a concentration of 25 microM TBT whereas 79% growth was recorded in the presence of phosphate ions. Tris ions caused more protein to be released into the medium than phosphate ions. However, apart from protein release the rate of organotin uptake was less in Tris than in phosphate ions. Phosphate ions may play a positive role in the active accumulation of organotin into E. coli cells by providing cellular energy.

Bacterial Proteins↗
PubMed1989

Toxicity of dibutyltin, tributyltin and other organotin compounds to humans and to experimental animals.

Alkyltin compounds are used as stabilizers and antifouling agents. Food chain accumulation and bioconcentration have been demonstrated in crabs, oysters and salmon exposed to tributyltin oxide. In mammalian species, tributyltin compounds may be metabolized to dibutyltin derivatives and related metabolites. Di- and tributyltins appear to be less potent neurotoxicants than trimethyltins and triethyltins. Dibutyltins and tributyltins produced bile duct damage in rats, mice and hamsters. Tributyltin oxide and dibutyltin and dioctyltin compounds are potent thymolytic and immunotoxic agents in rats. Tributyltin oxide at 5 ppm in the rat diet produced immunotoxicity in a 2-year feeding study, and at 50 ppm increased the incidence of tumors of endocrine origin. In preliminary reports, 5 ppm tributyltin produced no detectable increase in tumor incidence, and 0.5 ppm produced no detectable immunotoxicity in long-term studies. Tributyltin oxide and dibutyltin acetate did not appear to be mutagenic in a large battery of mutagenicity assays but produced base-pair substitutions in one of the bacterial strains tested. Tributyltin oxide produced mutations in Chinese hamster ovary cells, increased the incidence of micronuclei in the erythrocytes of exposed male BALB/c mice, and was highly embryotoxic in vitro. Embryotoxic and teratogenic effects in mice exposed to tributyltin oxide in vivo may have been due either to direct tributyltin oxide action or responses secondary to maternal toxicity. More information is needed to determine the applicability to human risk assessments of the immunotoxicity data derived from rat studies and to establish a definitive tolerable daily intake for tributyltin oxide.

Animals↗
PubMed1976

Application of tributyltin chloride to the separation and column chromatography of thiols.

Tributyltin chloride (TBT) has the properties of a liquid anion exchanger with a special affinity for sulphydryl groups. Thiols such as cysteine can be separated by extraction from aqueous solution with organic solvents in the form of TBT mercaptides. The graphs of extraction coefficient verus pH have maxima whose positions depend on the nature of the thiols. Thiols can be separated from each other by using TBT on polyamide as the column packing and elution with buffers of gradually increasing or decreasing pH.

Chromatography, Affinity↗