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PubMed2003

Biocompatibility of hydroxylated metabolites of BISGMA and BFDGE.

Unpolymerized dental monomers can leach out into the oral biophase and are bioavailable for metabolism. We hypothesize that metabolites would be less toxic than parent monomers. We first identified the formation of metabolites from bisphenol F diglycidyl ether (BFDGE) and Bisphenol A glycidyl methacrylate (BISGMA) after their exposure to liver S9 fractions. Then, the metabolites and parent compounds were subjected to in vitro cytotoxicity, mutagenicity, and estrogenicity studies. Bisphenol A bis(2,3-dihydroxypropyl) ether and bisphenol F bis(2,3-dihydroxypropyl) ether were the hydroxylated metabolites of BISGMA and BFDGE, respectively. Cytotoxicity against L929 cells showed that the metabolites were significantly (p < 0.05) less cytotoxic than the parent monomers. Only BFDGE was mutagenic in the Ames assay with strain TA100 of Salmonella typhimurium. Parent and metabolite compounds did not stimulate estrogen-dependent MCF-7 cell proliferation above solvent controls. These results indicated that the hydroxylated metabolites were non-mutagenic, non-estrogenic, and less cytotoxic than their parent monomers.

Animals↗

PubMed2001

Simultaneous determination of phenolic xenoestrogens by solid-phase extraction and high-performance liquid chromatography with fluorescence detection.

A highly sensitive and selective method for simultaneous determination of some hydroxyl group-containing endocrine disruptors, including bisphenol A (BPA), bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF) and 4-nonylphenol (4-NP), was developed. The method consists of precolumn derivatization of the analytes, solid-phase extraction (SPE) and subsequent chromatographic analysis by high-performance liquid chromatography (HPLC) with fluorescence detection. 4,4'-Cyclohexylidenebisphenol (BPZ) was used as an internal standard. Derivatization was carried out using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) as a label. Parameters of the derivatization reaction (temperature, time, concentration of reagent, stability, etc.) and of the solid-phase extraction (recovery, solvent, etc.) were studied in detail. Detection limits of compounds studied in standard solutions ranged from 0.08-1.3 ppb (ng/ml). The proposed method was successfully applied to plastic samples; BPA was found in both polycarbonate and polyvinyl chloride plastics, while 4-NP was found in plastics made of polyvinyl chloride and another polymer.

Benzhydryl Compounds↗

PubMed1992

Radiolabelled calmodulin ligands: their low affinity and high lipophilicity may lead to artefacts in binding studies.

In order to characterize the interaction site of a series of putative calmodulin antagonists of the diphenylalkylamine type with calmodulin (CaM), a representative member of this chemical class was radiolabelled. The binding of the selected compound, [3H]-VUF 4576, to calmodulin was studied according to a recently described technique using CaM agarose. However, some peculiar results were obtained: the tight binding of [3H]-VUF 4576 increased in presence of cold VUF 4576, resulting in a high non-specific binding. The unexpected results could readily be explained by a high binding capacity of the labelled compound and the cold ligands to the walls of the test tubes used. Such results were also found when [3H]-chlorpromazine ([3H]-CPZ) was applied. In literature comparable findings have been published. To explain such results the influence of positive cooperativity or irreversible binding has been suggested. We suppose that not only in our study, but also in other published investigations, binding to glass of the radioligand and/or the cold compounds may have had a strong influence. We suggest, therefore, that care should be taken in interpreting non-classical displacement data obtained with ligands which combine a rather low affinity and a high degree of lipophilicity, not only for binding to calmodulin, but for other systems as well.

Benzhydryl Compounds↗

PubMed1982

Pharmacokinetics and biotransformation studies of terfenadine in man.

Comparison of plasma level data obtained from a dose-response study to that of a 14C material balance study indicates that 99.48% of the alpha-[4-(1,1-dimethylethyl)phenyl] 4-(hydroxydiphenylmethyl)-1-piperidinebutanol (terfenadine, RMI 9918, Triludan, Teldane, resp.) related material absorbed undergoes biotransformation. From the balance study it has been determined that fecal excretion accounts for ca. 60% of the dose administered. Thin-layer chromatographic analysis of urine and feces revealed the presence of two major metabolic products. These compounds have been isolated and their structures determined by GC-MS. One of the metabolic products, a carboxylic acid analog of terfenadine has been shown to have antihistaminic activity and may play a role in the activity of the parent drug in vivo.

Benzhydryl Compounds↗

PubMed2001

Synthesis and preliminary characterization of a high-affinity novel radioligand for the dopamine transporter.

In our effort to develop a novel radioligand selective for the dopamine transporter, compound 1b (O-972) was designed and characterized. The compound 1b was characterized for its binding both in monkey and rat striatum tissue, which demonstrated its high selectivity for the dopamine transporter (DAT) when its binding was compared with that at the serotonin transporter (SERT). The compound 5, which is a precursor for the tritiated radiolabel ligand [3H]O-972, was synthesized and biologically characterized. The preliminary characterization of this novel radioligand revealed its strong binding affinity for the DAT. Thus, the pharmacological profile of [3H]O-972 indicated that DAT inhibitors, which include GBR 12909, mazindol, CFT, and cocaine, could potently displace this novel radioligand from monkey brain striatum tissue. On the other hand, compounds known to be not selective for and potent at the DAT were very weak to do so. Initial binding results also indicate that [3H]O-972 may interact with the DAT in a manner that is not identical to that for GBR 12909 and tropane analogs.

Animals↗

PubMed2004

The endocrine disrupting effect of municipal effluent on the zebra mussel (Dreissena polymorpha).

Municipal effluents have been shown to contain a cocktail of endocrine disrupting chemicals (EDCs). The estrogenic effect of these effluents has been demonstrated on both vertebrate and invertebrate species by the feminisation of the exposed males. This effect was investigated on the freshwater zebra mussel (Dreissena polymorpha) after exposure to tertiary treated effluent from a municipal sewage treatment works (STW). Mussels were exposed to the effluent in situ for 112 days during gametogenesis (December to mid-March). Levels of vitellin (Vn)-like proteins (the major protein found in oocytes) were measured indirectly using the alkali-labile phosphate (ALP) technique and confirmed by gel electrophoresis. Significant increases (P < 0.05) in Vn-like proteins were found in both male and female mussels after exposure to the effluent, indicating that endocrine disruption (ED) had occurred. Using High-performance thin layer chromatography (HPTLC) levels of the mussels main steroid, cholesterol were found to more than double after effluent exposure. General physiological (survival, condition, etc.) and histological effects were also investigated. Histological effects observed included a large increase in interstitial tissue between the seminiferous tubules of the gonad in male mussels exposed to effluent. Effluent samples were tested for estrogenic compounds using the toxicity identification and evaluation method (TIE). A complex mixture of compounds with estrogenic activity was found with 17beta-estradiol, 17alpha-ethynlestradiol and bisphenol A accounting for the majority of the effluents estrogenic activity. Results indicate that the zebra mussel is a suitable bioindicator of endocrine disruption in freshwater environments.

Analysis of Variance↗

PubMed2003

High affinity hydroxypiperidine analogues of 4-(2-benzhydryloxyethyl)-1-(4-fluorobenzyl)piperidine for the dopamine transporter: stereospecific interactions in vitro and in vivo.

In our effort to develop high-affinity ligands for the dopamine transporter which might find potential use as cocaine medication, a polar hydroxy substituent was introduced into the piperidine ring of one of our disubstituted lead analogues derived from 1-[2-(diphenylmethoxy)-ethyl]-4-(3-phenylpropyl)piperazine (GBR 12935). Both cis- and trans-3-hydroxy derivatives were synthesized and the racemic trans isomer, (+/-)-5, was further resolved into two enantiomers. Newly synthesized compounds were characterized for their binding affinity at the dopamine, serotonin, and norepinephrine transporter systems in rat brain. The two enantiomers (+)-5 and (-)-5 exhibited marked differential affinities at the dopamine transporter with (+)-5 being 122-fold more potent than (-)-5 in inhibiting radiolabeled cocaine analogue binding (IC(50); 0.46 vs 56.7 nM) and 9-fold more active for inhibiting dopamine uptake (IC(50); 4.05 vs 38.0 nM). Furthermore, the most active (+)-5 was 22-fold more potent at the dopamine transporter compared to the standard GBR 12909. Absolute configuration of one of the enantiomers was determined unambiguously by X-ray structural analysis. In in vivo locomotor activity studies, the enantiomer (+)-5 and the racemic (+/-)-5, but not (-)-5, exhibited stimulant activity with a long duration of effect. All three compounds, (+)-5, (-)-5, and (+/-)-5, within the dose range tested, partially (50%) but incompletely (80%) produced cocaine-like responses in mice trained to discriminate 10 mg/kg ip cocaine from vehicle. Compound (-)-5 was distinctive in this regard in that, unlike (+)-5 and (+/-)-5, it did not affect locomotor activity yet, but similar to them, was able to engender (albeit incompletely) cocaine-like responses.

Animals↗

PubMedDate not supplied

Contact allergy to 2,4'-dihydroxy-(hydroxymethyl)-diphenyl methanes. Sensitizers in a phenol-formaldehyde resin.

A particular phenol-formaldehyde resin of the resol type (P-F-R-2) was shown to be a good marker for patients with contact allergy. Eleven patients with sensitivity to P-F-R-2 participated in the study in which chromatographically separated fractions of P-F-R-2 were patch tested. This procedure was repeated until a positive reaction to a single substance was noted. In this study 2 sensitizers are reported. Investigations by mass-spectrometry and nuclear magnetic resonance spectrometry identified the compounds to be 2,4'-dihydroxy-3,3'-di-(hydroxymethyl)-diphenyl methane (2,4'-H-3,3'-HPM) and 2,4'-dihydroxy-3',5'-di-(hydroxymethyl)-diphenyl methane (2,4'-H-3',5'-HPM). Six of 11 patients reacted to at least one of the compounds and simultaneous reactions were noted in 4 patients. By patch testing with serial dilutions of the two sensitizers positive reactions were noted down to 0.14 X 10(-3)% and 0.41 X 10(-3)% w/v for 2,4'-H3,3'-HPM and 2,4'-H-3',5'-HPM respectively.

Benzhydryl Compounds↗

PubMed2004

Vascular medial hyperplasia following chronic, intermittent exposure to 4,4'-methylenedianiline.

4,4'-Methylenedianiline (DAPM) is an aromatic amine used in the synthesis of polyurethanes and epoxy resins. Acute exposure to DAPM produces hepatobiliary toxicity in humans as well as animal models. However, the toxic effects of intermittent DAPM exposure have not been explored. We treated male and female rats with 25 mg DAPM/kg or vehicle once per week for 17-22 wk. Though concentric fibrosis around bile ducts of the liver was noted, vascular medial hyperplasia was also prominent. Morphometric analysis of histologic sections revealed that in male rats, vessel wall area increased relative to lumen area in hepatic arteries by 22 wk. However, in female rats, wall areas of both hepatic and pulmonary arteries increased relative to lumen area by 17 wk. In both male and female rats, increased wall thickness was localized to the medial layer; no intimal changes were noted. In vitro treatment of vascular smooth muscle cells (VSMC) with 25-100 microM DAPM resulted in increased DNA synthesis and VSMC proliferation. To test whether the observed alterations in cell cycle control involved VSMC-mediated metabolism of DAPM to electrophilic intermediates, cells were treated with DAPM or DAPM plus 50 microM N-acetylcysteine (NAC). Coincubation with NAC afforded dramatic protection against DAPM-induced VSMC proliferation. Though DAPM had no appreciable effect on levels of reduced glutathione, oxidized glutathione, or oxidant production, DAPM increased glutathione-S-transferase activity in VSMC. These data indicate that DAPM can initiate VSMC proliferation, possibly via VSMC-mediated metabolism of DAPM to reactive intermediates.

Acetylcysteine↗

PubMed2000

Mammalian cell transformation and aneuploidy induced by five bisphenols.

Bisphenol-A (BP-A), a monomer of plastics used in numerous consumer products and a xenoestrogen, induces cellular transformation and aneuploidy in Syrian hamster embryo (SHE) cells. In this study, the abilities of 4 other bisphenols to induce cellular transformation and genetic effects in SHE cells were examined and compared to BP-A. Cellular growth was inhibited by all bisphenols in a concentration-related manner. The growth inhibitory effect of the bisphenols ranked: BP-5 > BP-4 > BP-3 > BP-2 or BP-A. Morphological transformation of SHE cells was induced by BP-A, BP-3, BP-4 and BP-5, and the induced-transformation frequencies were highest with BP-4. None of the bisphenols induced gene mutations at the Na(+)/K(+) ATPase locus or the hprt locus, or chromosomal aberrations in SHE cells. By contrast, aneuploidy induction in the near-diploid range was exhibited by BP-A, BP-3, BP-4 or BP-5, corresponding to the transforming activity of each compound. The results indicate that BP-A, BP-3, BP-4 and BP-5 exhibit transforming activity in SHE cells, while BP-2 does not, and that aneuploidy induction may be a causal mechanism of the transforming activity.

Aneuploidy↗

PubMed1980

Antimuscarinic agents: furan analogs of benzilate esters.

The methiodide and ethiodide salts of 5-(dimethylaminomethyl)- and 5-(diethylaminomethyl)-alpha, alpha-diphenylfurfuryl alcohol were prepared, These compounds may be considered as furan analogs of dialkylaminoethyl benzilate alkiodides. The pA2 values of these compounds as antagonists of acetylcholine were determined on rat jejunum preparation. All four compounds were significantly less potent than the analogous ester antimuscarinic lachesine. The furan ring cannot be substituted for the ester moiety of typical antimuscarinics. Possible modes of binding by antagonists to the receptor proposed previously are considered that might account for this less-than-expected antimuscarinic activity.

Animals↗

PubMed2005

A study of the preparation and reactivity of potassium ferrate.

In the context of water treatment, the ferrate ([FeO(4)](2-)) ion has long been known for its strong oxidizing power and for producing a coagulant from its reduced form (i.e. Fe(III)). However, it has not been studied extensively owing to difficulties with its preparation and its instability in water. This paper describes an improved procedure for preparing solid phase potassium ferrate of high purity (99%) and with a high yield (50-70%). The characteristics of solid potassium ferrate were investigated and from XRD spectra it was found that samples of the solid have a tetrahedral structure with a space group of D(2h) (Pnma) and a=7.705A, b=5.863A, and c=10.36A. The aqueous stability of potassium ferrate at various pH values and different concentrations was investigated. It was found that potassium ferrate solution had a maximum stability at pH 9-10 and that ferrate solution at low concentration (0.25 mM) was more stable than at high concentration (0.51 mM). The aqueous reaction of ferrate with bisphenol A (BPA), a known endocrine disrupter compound, was also investigated with a molar ratio of Fe(VI):BPA in the range of 1:1-5:1. The optimal pH for BPA degradation was 9.4, and at this pH and a Fe(VI):BPA molar ratio of 5:1, approximately 90% of the BPA was degraded after 60s.

Benzhydryl Compounds↗

PubMed2000

Vasostabilizing effect of Dotarizine (Ca(2+)-channel blocker) on cerebrovascular reactivity in rabbits.

Disturbances of the cerebrovascular reactivity in cases of migraine with aura are well-known. It has been suggested that the vasostabilizing effects of novel prophylactic pharmaceuticals are determined by their antiserotoninergic and/or nitric oxide releasing properties. Dotarizine, a representative of Ca2+ channel blockers from diphenilbutilpiperazines group also reveals antiserotoninergic 5-HT2A and 5-HT2C receptor-specific properties. The vasodilatatory and antivasoconstrictive properties of this compound were reported previously. In this study the efficacy of Dotarizine chronic oral administration on cerebrovascular reactivity during hyperventilation was examined with respect to its duration of action. Experiments were carried out on 13 rabbits. There was an interval of two days between a five days compound administration and performed hyperventilation. Blood flow velocities (BFV) in the middle cerebral artery (MCA) and basilar artery (BA) were measured in control conditions, after 10 min hyperventilation and in the tenth minute of recovery of normoventilation. Our data reveal a decrease of antivasoconstrictive properties of Dotarizine between its administration and vasoconstrictive test. Subsequent normoventilation showed a distinct vasostabilising effect of this compound with evident regional differences in its influence on cerebral vessels. Thus Dotarizine might be useful as prophylactic medication in migraine therapy, due to its Ca2+ channel blocking and antiserotoninergic properties, but the time-frame of its efficacy has to be defined.

Animals↗

PubMed1983

A method for the collection and determination of phenol and bisphenol A in air.

An analytical method has been developed for the determination of phenol and bisphenol A in air. Air samples are concentrated on commercial silica by the well established tube-pump method. The trapped components are desorbed and analyzed by HPLC using UV detection at 275 nm. The method has been validated for a concentration range of 0.5-50 mg m-3 (based on a 10-l air sample) for both compounds. Linearity of response, adsorption/desorption efficiency, influence of humidity on sample collection and influence of temperature and time on storage of collected samples were studied. The reported technique provides a selective and sensitive method for environmental monitoring in industrial atmospheres as well as for personnel exposure measurement.

Air↗

PubMed2000

Metabolism and cytotoxicity of bisphenol A and other bisphenols in isolated rat hepatocytes.

The relation between the metabolism and the cytotoxic effects of bisphenol A (BPA, 2,2-bis(4-hydroxyphenyl)propane) has been studied in freshly isolated rat hepatocytes and isolated hepatic mitochondria. The incubation of hepatocytes with BPA (0.25-1.0 mM) elicited a concentration- and time-dependent cell death, accompanied by losses of intracellular ATP and total adenine nucleotide pools. BPA at a low-toxic level (0.25 mM) in the hepatocyte suspensions was rapidly converted to its major conjugate, BPA-glucuronide, and other minor products without marked loss of cell viability, although at a toxic level (0.5 mM), more than 65% of the compound presented in an unaltered form 2 h after the incubation. Addition of salicylamide (2 mM), non-toxic to hepatocytes during the incubation period, enhanced BPA-induced cytotoxicity and reduced the loss of BPA and the formation of BPA-glucuronide. The addition of BPA to isolated hepatic mitochondria caused a concentration (0-0.5 mM)-dependent increase in the rate of state 4 oxygen consumption in the presence of an FAD-linked substrate (succinate), indicating an uncoupling effect, whereas the rate of state 3 oxygen consumption was inhibited by BPA. Further, the addition of BPA (0.25 mM) reduced state 3 respiration with NAD+-linked substrates (pyruvate plus malate) and/or with the FAD-linked substrate, whereas state 3 respiration with ascorbate plus tetramethyl-p-phenylenediamine (cytochrome oxidase-linked respiration) was not significantly affected by BPA. A comparative study of the toxic effects of BPA and some bisphenols on cell viability (at 1.0 mM) and mitochondrial respiration (at 0.25 mM) revealed that 4,4'-(1,2-diethyl-1,2-ethenediyl)bisphenol (diethylstilbestrol) was more toxic than BPA, followed by 4,4'-methylenediphenol and 4,4'-biphenol. These results indicate that the onset of cytotoxicity caused by BPA may depend on the intracellular energy status and that mitochondria are important targets of the compound. The toxicity caused by the inhibition of ATP synthesis may be related to the concentration of unmetabolised free BPA remaining in the cell suspensions. In addition, the toxic potency of bisphenols to hepatocytes and mitochondria depends on the relative elongation and/or molecular size of the hydrocarbon bridge between the phenolic groups.

Adenosine Triphosphate↗

PubMed1991

Microcalorimetric investigation of the complexation between 2-hydroxypropyl-beta-cyclodextrin and amine drugs with the diphenylmethyl functionality.

Solution calorimetry has been employed to evaluate the stability constants and standard-enthalpy changes (delta H degrees) associated with complex formation between 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and a group of amine compounds having the diphenylmethyl functionality in aqueous solution at 298.15 K. Data from microcalorimetric titrations of the compounds were analysed using a nonlinear least-squares method. Of the 12 compounds studied, only terfenadine.HCl formed a 1:2 (compound:HP-beta-CD) complex. All the others formed 1:1 complexes. The standard free energy decrease accompanying the formation of inclusion complexes is generally due to a negative delta H degrees. This exothermic delta H degrees can be interpreted as indicating that the binding forces for complexation include both the hydrophobic effect and strong van der Waals interactions. When a halogen substituent is in the aromatic ring, stability constants are higher and standard-entropy changes (delta S degrees) become positive, suggesting greater hydrophobic interaction. Both adiphenine.HCl and proadifen.HCl form more stable complexes, suggesting that hydrogen bonding to the carbonyl oxygen by the hydroxyl-group on the rim of the CD ring could be an important contributor to the complexation. Substitution on the aliphatic carbon of the diphenylmethyl group was also found to be important in determining the ability of compounds to bind with HP-beta-CD. The independence of the thermodynamic constants on the degree of protonation in the case of bifunctional amines indicates that the amine functional groups do not penetrate into the HP-beta-CD cavity.

2-Hydroxypropyl-beta-cyclodextrin↗

PubMed1989

[Treatment of histamine-dependent allergic dermatoses with a 120-mg terfenadine tablet once a day].

Terfenadine, an anti-H1-selective antihistaminic drug has been used in an experimental clinical study. The effectiveness and tolerance of the compound in the treatment of pruritic dermatitis such as urticaria, atopic dermatitis and topical dermatitis, have been evaluated. Terfenadine, administered in 120 mg tablets in a single daily dose in 30 patients demonstrated a fully satisfactory therapeutic activity and reliability of use.

Administration, Oral↗

PubMed2001

Oxidation of bisphenol A and related compounds.

Bisphenol A was oxidized to monoquinone and bisquinone derivatives by Fremy's salt, a radical oxidant, though salcomine and alkali did not catalyze the oxidation by molecular oxygen. Bisphenol A, bisphenol B, and 3,4'-(1-methylethylidene)bisphenol were converted to their monoquinone derivatives in the presence of tyrosinase at 25 degrees C at pH 6.5, but not to the bisquinone derivatives under these conditions.

Benzhydryl Compounds↗