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PubMed1989

Immunotoxicity of tributyltin oxide in rats exposed as adults or pre-weanlings.

A comparison was made between adult and pre-weanling rats of the immunotoxic effects of subacute dosing with bis(tri-n-butyltin) oxide (TBTO). Adult (9 weeks old) male Fischer rats were dosed by oral gavage with TBTO for 10 consecutive days at 1.25-10 mg/kg per dose or 3 times/week for a total of 10 doses at 5-20 mg/kg per dose. Adult rats similarly dosed by oral gavage with 6 mg/kg per dose cyclophosphamide (CY) served as positive controls. Pre-weanling rats (3-24 days old) were dosed 3 times/week for a total of 10 doses at 2.5, 5 or 10 mg/kg per dose. At various times after dosing rats were evaluated for alterations in body and lymphoid organ weights, mitogen and mixed lymphocyte reaction (MLR) lymphoproliferative (LP) responses, natural killer (NK) cell activity, cytotoxic T lymphocyte (CTL) responses and primary antibody plaque-forming cell (PFC) responses. In adult rats given 10 daily doses of TBTO, thymic involution was observed at a dosage of 2.5 mg/kg and mitogen responses to Con A and PHA were suppressed at 5 mg/kg. The PFC response was enhanced in adult rats dosed daily at 2.5 mg/kg. A dosage of 5 mg/kg given intermittently (3 times/week) to adults or pre-weanlings resulted in thymic involution. Reductions in mitogen responses were observed in adults dosed intermittently at 10 and 20 mg/kg and in pre-weanlings at 5 and 10 mg/kg. The MLR response was suppressed in adult rats dosed intermittently at 20 mg/kg and in pre-weanling rats at 10 mg/kg. NK cell activity was suppressed only in pups dosed intermittently at 10 mg/kg. CTL responses were not affected in either age group. Within 3 weeks following the last exposure of adult rats to TBTO all parameters returned to normal. On the other hand, LP responses to mitogens were suppressed in 10-week-old rats that were dosed with 10 mg/kg TBTO as pre-weanlings. However, this exposure regimen in reductions in body weight that persisted for up to 13 weeks of age, which suggests that TBTO may be a developmental toxicant. These data indicate that while exposure of young rats to TBTO resulted in immune alterations at doses lower than those required to suppress responses in adults, the observed effects may also be influenced by the developmental toxicity of this compound.

Age Factors↗
PubMed1994

Effect of tri-n-butyltin on intracellular Ca2+ concentration of mouse thymocytes under Ca(2+)-free condition.

Effect of tri-n-butyltin at concentrations ranging from 100 nM to 1 microM on the intracellular Ca2+ concentration of mouse thymocytes was examined under Ca(2+)-free conditions in comparison with those of 50 nM A23187, 100 nM thapsigargin and 10 microM cyclopiazonic acid, using the fluorescent dye for intracellular Ca2+, fluo-3. Tri-n-butyltin persistently increased the intensity of fluo-3 fluorescence while A23187, thapsigargin and cyclopiazonic acid produced a transient augmentation of the fluorescence. Pretreatment with A23187 greatly decreased the fluorescence responses induced by 1 microM tri-n-butyltin. However, the effect of thapsigargin and cyclopiazonic acid on the tri-n-butyltin-induced response was much weaker than that of A23187. In the presence of tri-n-butyltin, the transient response produced by A23187 was greatly prolonged. Results may suggest that tri-n-butyltin increases the membrane Ca2+ permeability of the intracellular organelles (cellular calcium stores) and decreases the Ca2+ pump activity of thymocyte membrane, resulting in a sustained increase in the intracellular Ca2+ concentration under Ca(2+)-free concentration.

Aniline Compounds↗
PubMed2006

Stereocontrolled synthesis of the D- and L-glycero-beta-D-manno-heptopyranosides and their 6-deoxy analogues. Synthesis of methyl alpha-l-rhamno-pyranosyl-(1-->3)-D-glycero-beta-D-manno-heptopyranosyl- (1-->3)-6-deoxy-glycero-beta-D-manno-heptopyranosyl-(1-->4)-alpha-L- rhamno-pyranoside, a tetrasaccharide subunit of the lipopolysaccharide from Plesimonas shigelloides.

The synthesis of d- and l-glycero-alpha-manno-thioheptopyranosides, protected with 4,6-O-alkylidene-type acetals is described. In glycosylations carried out with preactivation with the 1-benzenesulfinylpiperidine/trifluoromethanesulfonic anhydride couple, both the D- and L-glycero series exhibit excellent beta-selectivity with a range of glycosyl acceptors. In contrast, a 4,7-O-alkylidene acetal was found not to afford beta-selectivity. With a 4,6-O-[1-cyano-2-(2-iodophenyl)ethylidene] acetal protected thioglycoside, excellent beta-selectivity was obtained in glycosylation reactions, and subsequent treatment with tributyltin hydride and azoisobutyronitrile brought about clean fragmentation to the 6-deoxy-glycero-beta-D-manno-heptopyranosides. This chemistry was applied to the stereocontrolled synthesis of methyl alpha-L-rhamno-pyranosyl-(1-->3)-D-glycero-beta-D-manno-heptopyranosyl-(1-->3)-6-deoxy-glycero-beta-D-manno-heptopyranosyl-(1-->4)-alpha-L-rhamno-pyranoside, a component of the lipopolysaccharide from Plesimonas shigelloides.

Acetals↗
PubMed1986

Effects of various inhibitors of oxidative phosphorylation on energy metabolism, macromolecular synthesis and cyclic AMP production in isolated rat thymocytes. A regulating role for the cellular energy state in macromolecular synthesis and cyclic AMP production.

Inhibitors of oxidative phosphorylation such as several triorganotin compounds, oligomycin, 2,4-dinitrophenol and carbonylcyanide p-trifluoromethoxyphenylhydrazone suppress energy metabolism of isolated rat thymocytes as indicated by a reduction of ATP levels, an increase in glucose consumption and by a marked accumulation of lactate. Also these compounds effectively inhibit the incorporation of DNA, RNA and protein precursors into acid-precipitable material of thymocytes. Moreover, the prostaglandin E1-induced elevation of cAMP is markedly reduced by these inhibitors. A correlation is observed between the effects on energy metabolism, macromolecular synthesis and cAMP production, since from a series of trialkyltin chlorides, tri-n-propyltin, tri-n-butyltin and tri-n-hexyltin are very effective inhibitors of these functions, while trimethyltin and tri-n-octyltin affect neither of them; other inhibitors of oxidative phosphorylation, each of them with quite different mechanisms of action, also inhibit macromolecular synthesis and cAMP production. The finding that a rise in intracellular ATP concentrations leads to a reversion of the tri-n-butyltin-induced inhibition of cAMP production and uridine incorporation, indicates a regulating role for the cellular energy state in these aspects of cellular function.

2,4-Dinitrophenol↗
PubMed2005

Tributyltin disturbs bovine adrenal steroidogenesis by two modes of action.

Tributyltin, an environmental pollutant, affected adrenal steroid hormone biosynthesis by two modes of action. Treatment of bovine adrenal cultured cells with 10-100 nM tributyltin for 48 h suppressed cortisol and androstenedione secretion, but induced the accumulation of 17alpha-hydroxyprogesterone and deoxycortisol, indicating that the P450(C21) and P450(11beta) activities were specifically suppressed. Direct inhibition of the enzymatic activities due to tributyltin was not observed in isolated organelles of untreated cells at concentrations less than 10 microM. Western blotting experiments using specific antibodies against steroidogenic enzymes showed that treatment with 1-100 nM tributyltin caused a decrease in cellular P450(C21) and P450(11beta) protein levels, and real-time PCR experiments showed that the decrease in protein content was attributable to decreases in mRNA of the enzymes. Tributyltin at concentrations higher than 100 nM suppressed all steroid biosynthesis in the adrenal cells. This suppression was closely correlated to the decrease in steroidogenic acute regulatory protein. Since nanomolar concentrations of tributyltin disturbed steroidogenesis in mammalian cells, there is the possibility that steroid hormone synthesis in polluted wild animals is affected by this compound.

Adrenal Cortex Hormones↗
PubMed1996

Accumulation pattern of butyltin compounds in dolphin, tuna, and shark collected from Italian coastal waters.

Tributyltin (TBT) and its breakdown products, mono-(MBT) and dibutyltin (DBT) were determined in bottlenose dolphin (Tursiops truncatus), bluefin tuna (Thunnus thynnus thynnus) and blue shark (Prionace glauca) collected from the Italian coast of the Mediterranean Sea in 1992-1993. Concentrations of total butyltin (BTs) in the liver of dolphin (1,200-2,200 ng/g wet wt) were an order of magnitude higher than in the blubber (48-320 ng/g wet wt). TBT was the predominant butyltin species in the blubber while DBT accounted for an higher proportion in the liver of dolphins. Butyltin concentrations in bluefin tuna were lower than those in dolphins, with TBT highest in the muscle and DBT in the liver. Concentrations of BTs in blue sharks were lower than those in dolphin and tuna, with kidney having the highest concentrations. TBT was the predominant form of butyltin derivatives in all the tissues of shark. Accumulation of butyltin compounds in liver/kidney seems to be associated with the presence of proteins such as glutathione.

Adipose Tissue↗
PubMed1984

Neuron-specific phosphoproteins as biochemical indicators of neurotoxicity: effects of acute administration of trimethyltin to the adult rat.

The cytoarchitecture of the adult central nervous system is expressed by proteins specific to individual cell types. In this investigation, a subclass of these proteins, the neuron-specific phosphoproteins, was examined after the administration of trimethyltin (TMT), a neurotoxicant which preferentially damages neurons in limbic structures. After acute administration of TMT (0.0-9.0 mg/kg i.v.), effects on neuronal phosphoproteins were examined by three separate techniques: endogenous phosphorylation of total synaptic membrane proteins; radiometric assay of synapsin I, a neuron-specific phosphoprotein associated with synaptic vesicles; and radioimmunoassay of synapsin I and protein III, another synapse specific, synaptic vesicle-localized phosphoprotein. All three procedures gave similar results. TMT caused dose- and time-dependent decreases in hippocampal phosphoproteins. These effects were large in magnitude and were still evident 14 weeks after exposure to TMT. Microdissection of slices of dorsal hippocampus did not reveal significant regional differences in the extent to which TMT affected synapsin I. Phosphoproteins in frontal cortex, unlike those in hippocampus, were not affected by TMT. Our findings are consistent with the neuropathological effects of this compound and suggest that neuron-specific phosphoproteins may be useful biochemical indicators of neurotoxicity.

Animals↗
PubMed1993

Inhibition of mouse spleen cell activity by organotin compounds: effect of attachment of a maltose residue to the organotin group.

Studies are reported on the inhibition of DNA synthesis and the lowering of cell viability caused by bis(tributyltin) oxide in mouse spleen cells cultured in the presence and absence of the B-lymphocyte mitogen, bacterial lipopolysaccharide. When a maltose residue is introduced into the organotin compound these toxic effects are increased. It is suggested that the maltose residue facilitates entry of the organotin compound into the cells.

Animals↗
PubMed2001

Small-scale survey on the contamination status of butyltin compounds in seafoods collected from seven Chinese cities.

Tributyltin (TBT) and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), in the commercial sea products collected from seven Chinese cities were measured to evaluate the extent of contamination and the potential adverse effect on health. Universal existence of butyltins was found in these samples, and the concentrations of TBT ranged from <6.9 to 17175 ng of Sn g(-1) of wet weight. The accumulation ratios of the pollutant in these organisms were as high as 10(3) or more compared with the previously reported data in corresponding water. The existing different accumulation capabilities of pollutants among the various seafood species were studied. It was observed that the butyltin compounds were comparatively stable during cooking or processing procedures in the manner of usual Chinese cooking way. The occurrence of butyltin compounds in sea products indicated a potential danger for the health of people who consumed seafood in these areas.

Animals↗
PubMed1999

Steady-state fluorescence and circular dichroism of trout hemoglobins I and IV interacting with tributyltin.

The effect of tributyltin chloride (TBTC) on rainbow trout (Salmo irideus) hemoglobin I (HbI) and hemoglobin IV (HbIV) was characterized by the steady-state fluorescence of intrinsic and extrinsic fluorescent probes. The fluorescence emission spectrum (lambdaex 280 nm) is greatly increased in intensity by the presence of the organotin in both proteins. Circular dichroism spectra in the same samples show a small decrease in theta222, a measure correlated with the percentage of the alpha-helical content. Morever, important changes in near-UV, Soret, and visible regions of CD were induced by TBTC. The correlation of data obtained with trout hemoglobins (HbI and HbIV) with similar measurements on globins suggests that the presence of heme is necessary for the interaction of the organotin compound with the proteins.

Anilino Naphthalenesulfonates↗
PubMed2002

Butyltin compounds in human liver.

Intake of marine food is the main source of butyltin exposure in humans. Health effects following exposure to butyltin compounds are usually in the immune system, but endocrine effects of butyltin from a variety of marine species have been documented. The information on human exposure to butyltin compounds and hepatic deposition is limited. The present study include 18 consecutively sampled human livers analyzed for butyltin compounds. Dibutyltin (DBT) concentrations varied between 0.8 and 28.3 ng/g with a mean concentration of 9.0 ng/g. Significantly lower concentrations of monobutyltin (MBT) were observed, ranging from 0.3 to 4.7 ng/g with a mean value of 1.6 ng/g. Age and DBT/MBT ratio were significantly associated. We suggest that younger men have more recent exposures or have a lower capacity to debutylate DBT than older men and would therefore potentially be more susceptible to butyltin toxicity. Given the interperson variability observed in our limited group of men, we cannot exclude that thresholds for either immunotoxicity or effects on the endocrine system may occur due to exposure to butyltin compounds alone or in combination with other environmental toxicants with similar target organs.

Adult↗
PubMed2006

Down-regulation of mdr1b mRNA expression in the kidneys of mice following maternal exposure to tributyltin chloride.

We investigated the change in renal mdr1b mRNA expression in offspring exposed to tributyltin chloride (TBTC) via the placenta and lactation or via lactation, using the real-time reverse transcription-polymerase chain reaction. Pregnant ICR mice were given water containing TBTC (0, 15, and 50 microg/ml) ad libitum from the start of pregnancy to weaning or from parturition to weaning. Exposure via the placenta and lactation significantly reduced the renal mdr1b level in offspring. Exposure to TBTC through the mother might impair the exclusion system of toxic compounds in offspring.

ATP Binding Cassette Transporter, Subfamily B↗
PubMedDate not supplied

Trimethyltin impairs retention of a passive avoidance task.

Trimethyltin is a neurotoxic organometal which produces neuronal damage in several limbic regions including the hippocampus, amygdala and the pyriform cortex. One administration of trimethyltin (5, 6 or 7 mg/kg) twenty one days prior to passive avoidance conditioning produced an impairment of retention when animals were tested 24 hours after training. Rats treated with trimethyltin exhibited shorter step-through latencies and freezing durations during the retention test. It was observed that the three dosages of trimethyltin were equally effective in disrupting retention performance. There retention deficits were not secondary to alterations in footshock sensitivity. The data presented here indicate that acute trimethyltin administration disrupted learning and memory. The compound might be a useful tool for examining the role of the limbic system in associative processes.

Analysis of Variance↗
PubMedDate not supplied

Contamination of organotin compounds and imposex in molluscs from Vancouver, Canada.

Gastropods and bivalves were collected at 15 sites at Vancouver and Victoria, Canada between 24 May and 7 June, 1999, to establish tissue concentrations of butyltin and phenyltin compounds, to record imposex symptoms in gastropods, and to assess the present status of organotin contamination around Vancouver. No neogastropods (such as Nucella lima) were found around Vancouver. Neogastropod populations could have been extirpated by severe TBT contamination in Vancouver, as relatively high concentrations of TBT were detected in tissues of Mytilus trossulus from Vancouver, and the neogastropods distributed in Vancouver might be sensitive to TBT. Recovery from imposex, however, was observed in neogastropod populations from three sites at Victoria and Mission Point. TBT contamination has continued around Vancouver, arising from continuous use of TBT in antifouling paints for vessels larger than 25 m in length; however, TBT has decreased around Victoria and Mission Point. Different patterns of TBT accumulation in tissue were observed among the bivalve species from Vancouver. The highest TBT concentration detected in Tresus capax suggested some possible adverse effects. TBT was the most predominant butyltin component in almost all bivalve specimens surveyed, suggesting a low rate of TBT metabolism. Phenyltin compounds were not detected in any molluscan specimens in this study.

Animals↗
PubMedDate not supplied

Synthesis and radioiodination of N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine tetrafluorophenyl ester: preparation of a radiolabeled phenylalanine derivative for peptide synthesis.

An investigation to prepare a phenylalanine derivative which could be radioiodinated and used directly in peptide synthesis was conducted. N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine tetrafluorophenyl ester was targeted and synthesized from N-Boc-p-iodo-L-phenylalanine. The requisite aryl stannylation reaction was found to be best conducted using the phenylalanine methyl ester. Thus, N-Boc-p-iodo-L-phenylalanine methyl ester was prepared and stannylated using bis(tributyltin) and tetrakis-(triphenylphosphine)palladium(0) in refluxing toluene to prepare N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine methyl ester. Demethylation with aqueous base was accomplished without racemization to yield N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine. Preparation of the targeted stannylphenylalanine tetrafluorophenyl ester was then accomplished using 2,3,5,6-tetrafluorophenol and 1,3-dicyclohexyl-carbodiimide in anhydrous THF. Iodination and radioiodination reactions of the targeted compound were conducted in MeOH/1% HOAc to yield 83-95% of the desired N-Boc-p-[*I]iodo-L-phenylalanine tetrafluorophenyl ester.

Iodine Radioisotopes↗
PubMed2000

Differential effects of tri-n-butylstannyl benzoates on induction of apoptosis in K562 and MCF-7 cells.

Tributyltin compounds have been shown to induce apoptosis by causing extracellular Ca2+ influx and generating reactive oxygen species (ROS). Several organotin compounds were reported to have differential cytotoxicity on various human cell lines depending on the length of the alkyl chain. In this report, the cytotoxic effects of three tri-n-butylstannyl (halo)benzoate compounds-tri-n-butylstannyl benzoate (TBSB), tri-n-butylstannyl-2,6-difluorobenzoate (TBSDFB) and tri-n-butylstannyl-2-iodobenzoate (TBSIB)-were studied on lymphocytic cells of human leukemic K562 lineage and epithelial cells of human breast cancer MCF-7 cells lineage. K562 cells were found to be more sensitive to these compounds than MCF-7 cells. Although the induction of apoptosis by the above compounds in K562 cells resulted from the extracellular Ca2+ influx and the generation of ROS, the initial amount of extracellular Ca2+ influx was greater in TBSB-treated K562 cells than the cells treated with either TBSDFB or TBSIB. Similarly, DNA fragmentation by endonucleases was observed as an early event in TBSB-treated K562 cells, which might be correlated with the initially greater extracellular Ca2+ influx. In contrast, MCF-7 cells were found to undergo apoptosis mainly because of the generation of ROS. The present results suggest that the differential effects of tributyltin compounds on induction of apoptosis in K562 and MCF-7 cells are largely attributable to the extent of extracellular Ca2+ influx.

Apoptosis↗
PubMed1986

On the role of seizure activity in the hippocampal damage produced by trimethyltin.

Trimethyltin (TMT) causes a pattern of hippocampal damage in rats that is similar to that caused by convulsant chemicals or seen in the brains of some human epileptics. Therefore, we investigated the possible role that TMT-induced seizure activity might play in the hippocampal damage produced by this organotin. The morphologic effects of systemically administered TMT were compared to those of kainic acid given by the same route. Unlike kainate, TMT produced seizures in only a subset of treated animals and with a latency of days rather than minutes. Evaluation of morphology during the acute seizure period revealed that TMT-induced seizures were associated with a variable pattern of granule and pyramidal cell necrosis and acute dendritic swelling in the two associational/commissural hippocampal pathways, one from CA3 to CA1-CA3 and the other from the hilus to the proximal dendrites of dentate granule cells. The TMT-induced damage contrasted sharply with the acute pattern of kainate-induced damage that consisted of acute dendritic swellings in the distal granule cell dendrites, hilus and mossy fiber region. TMT-treated rats that did not exhibit seizures in the one week after injection exhibited minimal pathology during this period. These results suggest that at least part of the damage to granule and pyramidal cells produced by TMT is mediated by the seizure activity produced by this compound. Although the resulting lesions to the CA1-CA3 pyramidal cells may appear similar in both TMT- and kainate-treated rats long after injection, evaluation of acute pathology during the active seizure phase indicates that these compounds induce seizure activity in different hippocampal pathways and cause different patterns of irreversible neuronal damage as a result.

Animals↗
PubMed1998

Macrophage secretory function is enhanced by low doses of tributyltin-oxide (TBTO), but not tributyltin-chloride (TBTCl).

Numerous studies suggest that tributyltin (TBT) is a potent immunotoxicant in nontarget organisms with lymphoid atrophy being a hallmark response. Two of the most common formulations of TBT are bis (tri-n-butyl)-tin oxide (TBTO) and tri-n-butyl-tin chloride (TBTCl). Most of studies investigating TBT-related immunotoxicity have used relatively high doses of both compounds, but little is known about the effects of very low doses. In addition, no studies have directly compared the effects of both formulations on immune function(s). We exposed female B6C3F1 mice to a single dose of TBTO or TBTCl at 0.3, 3.0, 30 mM/kg or corn oil as a carrier control. Forty-eight h later mice received a 4% solution of thioglycolate intraperitoneally to elicit peritoneal macrophages. Ninety-six h later macrophages were harvested and stimulated with a mixture of gamma-interferon (IFN-gamma) and lipopolysaccharide (LPS). Nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), transforming growth factor beta-1 (TGF-beta1), and phorbol ester-stimulated oxidative burst activity were then measured. Nitric oxide and TNF-alpha production were significantly elevated in the 0.3 and 3.0 mM TBTO/kg-treated groups but not in those treated by TBTCl. Background TNF-alpha production (without stimulation) was also elevated at these two doses but suppressed in TBTCl-treated animals. Oxidative burst activity was elevated at 0.3 mM TBTO/kg but not by TBTCl. TGF-beta1 production was not altered by either treatment, nor were body wts and organ-body wt ratios. To further evaluate the difference between the effects of TBTO and TBTCl on macrophage function, the in vitro toxicity of the two was determined using elicited peritoneal macrophages from untreated mice. Following a 24-h exposure to increasing concentrations of TBTO or TBTCl, functional viability was evaluated using the MTT assay. There were no differences between the two compounds in terms of treatment-related viability except that at the very highest concentrations (10(-6) M) TBTO was more toxic than TBTCl.

Animals↗