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PubMed1989

[Analysis of PCB- and PCT-methylsulfones in the blood in yusho patients].

Polychlorinated biphenyl (PCB)- and terphenyl (PCT)-methylsulfones were isolated from the blood of yusho patients sampled in 1987 and characterized by gas chromatography with mass spectrometry (GC/MS), electron capture detection (GC/ECD) and flame photometric detection (GC/FPD). GC/MS analysis for PCB-methylsulfones showed that all the blood tested (nine samples) contained the tri- and tetrachloro congeners. The concentrations of PCB-methylsulfones were estimated to be 15-120 ppb. PCT-methylsulfones detected in the same fraction, which were confirmed by GC/MS comparison with authentic samples as well as by GC/ECD and GC/FPD, consisted of tetra-, penta- and hexachloroterphenyl methylsulfone congeners. The levels of PCT-methylsulfones in six samples detected were preliminarily estimated to be 10-270 ppb, on the basis of a PCB-methylsulfone standard. Their origins and biological effects are unclear at present.

Food Contamination↗
PubMed2002

Cytotoxic effects of triphenylbismuth on rat thymocytes: comparisons with bismuth chloride and triphenyltin chloride.

The biomedical and industrial uses of organobismuth compounds have become widespread, although there is limited information concerning their cytotoxicity. Therefore, the actions of triphenylbismuth on rat thymocytes were examined using a flow cytometer with ethidium bromide, annexin V-FITC, fluo-3-AM, and 5-chloromethylfluorescein (5CMF) diacetate. Triphenylbismuth at 3-30 microM increased the population of cells stained with ethidium, indicating a decrease in cell viability. Organobismuth at 30 microM increased the population of cells positive to annexin V, suggesting an increase in the population of apoptotic cells. Triphenylbismuth at 3 microM or more decreased cellular glutathione content (5CMF fluorescence intensity) and increased intracellular Ca(2+) concentration ([Ca(2+)](i), fluo-3 fluorescence intensity) in a dose-dependent manner. Because an increase in [Ca(2+)](i) is linked to cell death or cell injury and a decrease in cellular glutathione content increases cell vulnerability to oxidative stress, the triphenylbismuth-induced changes in cellular parameters may be responsible for triphenylbismuth-induced cytotoxicity. Bismuth chloride at 10-30 microM did not significantly affect cell viability. These results suggest that triphenylbismuth at micromolar concentrations exerts cytotoxic action on rat thymocytes, possibly related to a health hazard. Although the cytotoxicity of triphenylbismuth was less than that of triphenyltin, one of the environmental pollutants, it is necessary to direct our attention to the use and disposal of organobismuth compounds.

Animals↗
PubMed2006

Synthesis of [(HIPTNCH2CH2)3N]Cr Compounds (HIPT = 3,5-(2,4,6-i-Pr3C6H2)2C6H3) and an evaluation of chromium for the reduction of dinitrogen to ammonia.

Red-black [HIPTN3N]Cr (1) ([HIPTN3N]3- = [(HIPTNCH2CH2)3N]3- where HIPT = 3,5-(2,4,6-i-Pr3C6H2)2C6H3 = HexaIsoPropylTerphenyl) can be prepared from CrCl3, while green-black [HIPTN3N]Cr(THF) (2) can be prepared from CrCl3(THF)3. Reduction of {1|2} (which means either 1 or 2) with potassium graphite in ether at room temperature yields [HIPTN3N]CrK (3) as a yellow-orange powder. There is no evidence that dinitrogen is incorporated into 1, 2, or 3. Compounds that can be prepared readily from {1|2} include red [HIPTN3N]CrCO (4), blood-red [HIPTN3N]CrNO (6), and purple [HIPTN3N]CrCl (7, upon oxidation of {1|2} with AgCl). The dichroic (purple/green) Cr(VI) nitride, [HIPTN3N]CrN (8) was prepared from Bu4NN3 and 7. X-ray studies have been carried out on 4, 6, and 7, and on two co-crystallized compounds, 7 and [HIPTN3N]CrN3 (65:35) and [HIPTN3N]CrN3 and 8 (50:50). Exposure of a degassed solution of {1|2} to an atmosphere of ammonia does not yield "Cr(NH3)" as a stable and well-behaved species analogous to Mo(NH3). An attempt to reduce dinitrogen under conditions described for the catalytic reduction of dinitrogen by [HIPTN3N]Mo compounds with 8 yielded a substoichiometric amount (0.8 equiv) of ammonia, which suggests that some ammonia is formed from the nitride but none is formed from dinitrogen.

Ammonia↗
PubMed2002

Reduction of dinitrogen to ammonia at a well-protected reaction site in a molybdenum triamidoamine complex.

We have synthesized a triamidoamine ligand ([(RNCH2CH2)3N]3-) in which R is 3,5-(2,4,6-i-Pr3C6H2)2C6H3 (HexaIsoPropylTerphenyl or HIPT). The reaction between MoCl4(THF)2 and H3[HIPTN3N] in THF followed by 3.1 equiv of LiN(SiMe3)2 led to formation of orange [HIPTN3N]MoCl. Reduction of [HIPTN3N]MoCl with magnesium in THF under dinitrogen led to formation of salts that contain the {[HIPTN3N]Mo(N2)}- ion. The {[HIPTN3N]Mo(N2)}- ion can be oxidized by zinc chloride to give [HIPTN3N]Mo(N2) or protonated to give [HIPTN3N]Mo-N=N-H. Other relevant compounds that have been prepared include {[HIPTN3N]Mo-N=NH2}+, [HIPTN3N]MoN, {[HIPTN3N]Mo=NH}+, and {[HIPTN3N]Mo(NH3)}+. (The anion is usually {B(3,5-(CF3)2C6H3)4}- = {BAr'4}-.) Reduction of [HIPTN3N]Mo(N2) with CoCp2 in the presence of {2,6-lutidinium}BAr'4 in benzene leads to formation of ammonia and {[HIPTN3N]Mo(NH3)}+. Preliminary X-ray studies suggest that the HIPT substituent creates a deep, three-fold symmetric cavity that protects a variety of dinitrogen reduction products against bimolecular decomposition reactions, while at the same time the metal is left relatively open toward reactions near the equatorial amido ligands.

Amines↗
PubMed1979

A new chemical series active against African trypanosomes: benzyltriphenylphosphonium salts.

Antitrypanosomal activity for benzyltriphenylphosphonium salts is reported for the first time. Testing was conducted using Trypanosoma rhodesiense infected mice. Of 70 phosphorus-containing compounds tested, 21 were active. Sixteen of these active chemical species were benzyltriphenylphosphonium salts. Four were nonbenzyl triphenyl compounds. The remaining active drug was a benzyldiphenylphosphonium salt.

Onium Compounds↗
PubMed1975

Nonclassical nicotine antagonists.

A series of "nonclassical" nicotine antagonists was synthesized and compared to the "classical" nicotine antagonist, hexamethonium, by means of the isolated guinea pig atria preparation. 2 was found to be the most potent, followed by hexamethonium and the other antagonists. With the exception of 5, the bisquaternary compounds 1-3 and 7-9 were found to be more potent than the monoquaternary compounds 4, 6, and 10-12. Within a series of compounds (1-6 or 7-12), those compounds possessing two phenyl rings proved to be more potent than those possessing one or three phenyl rings. These and other aspects of the structure-activity relationship of this class of compounds are discussed.

Animals↗
PubMed1994

Development of a radiopaque, autopolymerizing dental acrylic resin.

PURPOSE: Current prosthetic acrylic resins are radiolucent and cannot be imaged using standard radiographic techniques. If accidentally impacted or ingested, delays in localizing or removing the foreign body may be life-threatening. The purpose of this study was to evaluate the influence of an experimental radiopaque additive, triphenyl bismuth (TPB), on polymethyl methacrylate resins formulated for dental use. We also investigated methods to improve TPB-containing resin microbeads and optimize processing variables for specimen fabrication in autopolymerizing resin systems. MATERIALS AND METHODS: Selfcured samples of experimental resins were prepared containing 0% to 27% TPB and were tested according to American National Standards Institute/American Dental Association and International Organization for Standardization performance standards. A control group and two commercial provisional crown and bridge resins were used for comparison. RESULTS: The standard of radiopacity (> or = aluminum radiopacity) is met at TPB levels of > or = 14.5%. The control resin had a greater transverse deflection compared with the TPB-resin groups, but deflection was within standard limits for all resins. Polishability, color stability, and solubility were unaffected by TPB, whereas sorption decreased, although not significantly, at higher TPB levels. Translucency decreased at 27% TPB, and specimens containing 0% to 20% TPB were transparent. A tendency to entrain air bubbles, because of the hydrophobicity of TPB, resulted in increased susceptibility to brittle failure at the higher TPB levels. Solubility slightly exceeded American Dental Association standards for all TPB-resins and the control. All other performance standards were acceptable for resins containing 0% to 20% TPB. CONCLUSIONS: At concentrations that provide a diagnostic level of radiopacity, TPB does not significantly alter required performance and processing properties. Thus, TPB is capable of commercially acceptable performance as a radiopacifying additive for dental acrylics.

Analysis of Variance↗
PubMed2005

Osteolytic potential of triphenyl bismuth as an alternative contrast medium in acrylic bone cement.

Radiopaque cement containing barium sulfate causes significantly more bone resorption in vivo and in vitro than radiolucent cement. The aim of this study was to investigate the osteolytic potential of an alternative radiopaque agent, triphenyl bismuth (TPB). Bone cement particles containing various concentration of TPB (15 and 25 wt %) prepared by two methods, blending and dissolution, were added to monocytes in a bone resorption assay and the extent of lacunar resorption on dentine slices was determined. The results clearly show that cement particles containing TPB cause less bone resorption than cement particles containing barium sulfate. In addition, our results suggest that TPB prepared by dissolution in bone cement induces less osteolytic response than TPB-cement prepared by blending. The osteolysis in response to bone cement wear particles may therefore be reduced with TPB prepared using the blending technique.

Animals↗
PubMed2006

Synthesis of [(HIPTNCH2CH2)3N]V compounds (HIPT = 3,5-(2,4,6-i-Pr3C6H2)2C6H3) and an evaluation of vanadium for the reduction of dinitrogen to ammonia.

Green [HIPTN3N]V(THF) ([HIPTN3N]3- = [(HIPTNCH2CH2)3N]3-, where HIPT = 3,5-(2,4,6-i-Pr3C6H2)2C6H3) can be prepared in a 70-80% yield via the addition of H3[HIPTN3N] to VCl3(THF)3 in THF, followed by the addition of LiN(SiMe3)2. From [HIPTN3N]V(THF), the following have been prepared: {[HIPTN3N]VN2}K, [HIPTN3N]V(NH3), [HIPTN3N]V=NH, [HIPTN3N]V=NSiMe3, [HIPTN3N]V=O, [HIPTN3N]V=S, and [HIPTN3N]V(CO). No ammonia is formed from dinitrogen using {[HIPTN3N]VN2}K, [HIPTN3N]V=NH, or [HIPTN3N]V(NH3) as the initial species under conditions that were successful in the analogous [HIPTN3N]Mo system. X-ray structural studies are reported for [HIPTN3N]V(THF) and [HIPTN3N]V(NH3).

Ammonia↗
PubMed2004

Ring opening of nucleoside 1',2'-epoxides with organoaluminum reagents: stereoselective entry to ribonucleosides branched at the anomeric position.

Epoxidation of 3',5'-O-(di-tert-butylsilylene)-1',2'-unsaturated uridine (11) with dimethyldioxirane proceeded from the alpha-face to give the 1',2'-alpha-epoxide 12. Upon reacting with organoaluminum reagents, the 1',2'-alpha-epoxide 12 underwent preferential syn-opening of the epoxide ring to yield the beta-anomers of 1'-methyl- (13beta), 1'-ethyl- (14beta), 1'-isobutyl- (15beta), 1'-ethynyl- (16beta), 1'-vinyl- (17beta), and 1'-phenyl- (18beta) uridine derivatives, although the corresponding alpha-anomers were also formed except for the reaction with triphenylaluminum. It was found, however, that protection of the N(3)-position of 11 either with a benzyloxymethyl or benzoyl group led to the exclusive formation of the desired beta-anomers. A possible explanation for the observed stereochemical outcome is presented. A similar strategy was found to be applicable to the synthesis of 1'-branched adenosine analogues, which include protected angustmycin C (37).

Aluminum↗
PubMed2006

Accumulation of lipophilic dications by mitochondria and cells.

Lipophilic monocations can pass through phospholipid bilayers and accumulate in negatively-charged compartments such as the mitochondrial matrix, driven by the membrane potential. This property is used to visualize mitochondria, to deliver therapeutic molecules to mitochondria and to measure the membrane potential. In theory, lipophilic dications have a number of advantages over monocations for these tasks, as the double charge should lead to a far greater and more selective uptake by mitochondria, increasing their therapeutic potential. However, the double charge might also limit the movement of lipophilic dications through phospholipid bilayers and little is known about their interaction with mitochondria. To see whether lipophilic dications could be taken up by mitochondria and cells, we made a series of bistriphenylphosphonium cations comprising two triphenylphosphonium moieties linked by a 2-, 4-, 5-, 6- or 10-carbon methylene bridge. The 5-, 6- and 10-carbon dications were taken up by energized mitochondria, whereas the 2- and 4-carbon dications were not. The accumulation of the dication was greater than that of the monocation methyltriphenylphosphonium. However, the uptake of dications was only described by the Nernst equation at low levels of accumulation, and beyond a threshold membrane potential of 90-100 mV there was negligible increase in dication uptake. Interestingly, the 5- and 6-carbon dications were not accumulated by cells, due to lack of permeation through the plasma membrane. These findings indicate that conjugating compounds to dications offers only a minor increase over monocations in delivery to mitochondria. Instead, this suggests that it may be possible to form dications within mitochondria that then remain within the cell.

Adenosine Triphosphate↗
PubMed1986

Predicting the carcinogenicity of the aromatic amine derivatives tested in the second UKEMS Collaborative Study.

The carcinogenicity prediction and battery selection (CPBS) procedure was used to analyze the short-term in vitro and in vivo genotoxicity results obtained during the Second UKEMS Collaborative Study. In accordance with preliminary animal bioassay results, CPBS predicted correctly the carcinogenicity of benzidine, 4,4"-diaminoterphenyl and 4-dimethylaminoazobenzene. CPBS predicted the non-carcinogenicity of 4-cyanodimethylaniline, a chemical of as yet unknown carcinogenicity. Moreover, CPBS indicated that for the chemicals included in the UKEMS study, highly predictive as well as cost-effective batteries consisting of three short-term assays could be identified.

Aniline Compounds↗
PubMed1976

Species-specific hypoglycemic activity of triphenylphosphoranylideneacetophenones.

The species-specific hypoglycemic activity of two 2-triphenylphosphoranylideneacetophenones is described. 2-Triphenylphosphoranylideneacetophenone (SK&F 45359) and 2-triphenylphosphoranylidene-m-trifluoromethyl-acetophenone (SK&F 62775) were hypoglycemic in various rat models, but failed to exhibit hypoglycemic activity in other species.

Acetophenones↗
PubMed2000

The effect of triphenylbismuth on the radiopacity and performance properties of compression- and injection-molded denture resins.

PURPOSE: Methods of incorporating radiopaque triphenylbismuth into an experimental compression-molded and injection-molded heat-polymerized resins were determined. The transverse flexural properties, radiopacity, and color stability of the resins containing triphenylbismuth were then compared with a commercially available, compression-molded denture resin. MATERIALS AND METHODS: Varying levels of triphenylbismuth were added to both the monomer and polymer in heat-polymerized denture resin systems to determine the level of the additive that was necessary to achieve a radiopacity similar to 0.2 mm of copper with minimum resin porosity. Specimens were then prepared by incorporating 0% or 30% wt/wt triphenylbismuth into resins. The commercially available polymethyl methacrylate resin served as a benchmark for physical property comparison, and no additive was included during its polymerization. At 30% wt/wt triphenylbismuth, resin color stability, transverse deflection, and radiopacity were evaluated using methods described in International Standards Organization Standard 4049 and American Dental Association Specification No. 12. The transverse deflection results among the resin groups were compared with a reference resin using the Kruskal-Wallis method (alpha = 0.05). RESULTS: Incorporation of triphenylbismuth into the monomer of the injection material, resulting in 30% wt/wt in the polymerized resin, produced a level of radiopacity similar to 0.2 mm copper. Although the injection-molded resin with 30% wt/wt triphenylbismuth remained translucent, the compression-molded resin was opaque, indicating excessive air-entrapment porosity. The additive caused a faint yellowing in both types of resins, but color stability was not affected. Transverse deflection of the injection-molded resin (4.5 +/- 0.5 mm) and the injection-molded resin with triphenylbismuth (3.8 +/- 1.7 mm) was greater than that of the experimental resin (3.5 +/- 0.2 mm), which was equal to the commercial resin (3.6 +/- 0.2 mm). Triphenylbismuth at 30% wt/wt significantly reduced transverse deflection for the experimental resin (2.6 +/- 0.5 mm). CONCLUSIONS: Triphenylbismuth at a final concentration of 30% wt/wt can be added to polymethyl methacrylate injection-molded resins to provide a high level of detection on chest or abdominal radiographs without adversely affecting resin color stability and transverse deflection.

Benchmarking↗
PubMed1978

Mutagenicity testing of certified food colors and related azo, xanthene and triphenylmethane dyes with the Salmonella/microsome system.

Thirty-seven azo, xanthene and triphenylmethane dyes including FD and C colors currently approved for use in the U.S.A. and a number of delisted food colors, were tested in the Salmonella/microsome system. In addition to direct plate tests with five tester strains (TA1535, TA100, TA1537, TA1538, TA98), the azo dyes were also assayed after chemical reduction to their component amines. Also, a selected group of azo dyes was subjected to liquid tests (both aerobic with microsomes and anaerobic) and to plate tests involving initial 16 h anaerobic incubations to facilitate microbial reduction of the azo bond. None of the presently listed FD and C colors was mutagenic in any of the test modifications. Among formerly listed colors only Butter Yellow (p-dimethylaminoazobenzene), a recognized animal carcinogen, was mutagenic in the aerobic liquid test. Several other azo dyes were either directly mutagenic, viz. Acid Alizarin Yellow R and Alizarin Yellow GG; required microsomal activation, viz. Acid Alizarin Red B and Methyl Red; or required chemical reduction and microsomal activation, viz. Acid Alizarin Violet N and Sudan IV. Of the non-azo dyes tested only two xanthene dyes appeared to be mutagenic, viz. 9-(2-sulfophenyl)-6-hydroxy-3-isoxanthenone and its 2,4,5,7-tetrabromo derivative.

Azo Compounds↗
PubMed2002

Quantitative analysis of triphenylboron in environmental water samples by liquid chromatography/mass spectrometry.

Liquid chromatography/mass spectrometry (LC/MS) has been applied to the analysis of triphenylboron, which has been produced as a substitute for organotin compounds, in water. Although commercial triphenylboron compounds are produced as pyridinyl complexes, the chemical form in water is supposed to be mainly triphenylboron after liberating pyridine. The triphenylborons were extracted from water with an Empore C18 extraction disk under acidic condition, and the extracts were introduced directly into a liquid chromatograph-mass spectrometer equipped with a negative ion electrospray ionization interface. Identification of the compounds was performed with specific ions produced from the triphenylboron, and a quantitative analysis was carried out using the peak areas. The average recoveries from distilled water, seawater and river water at 0.30 ng/ml were 92.3, 100 and 85.3%, respectively. A detection limit of 0.023 ng/ml for triphenylboron was achieved.

Boron Compounds↗