Genotoxicity of the coating lacquer on food cans, bisphenol A diglycidyl ether (BADGE), its hydrolysis products and a chlorohydrin of BADGE

The epoxy resin bisphenol A diglycidyl ether (BADGE), its hydrolysis products and a chlorohydrin of BADGE (BADGE.2HCl), were examined for their genotoxicity in the micronucleus test (MNT) with human peripheral blood lymphocytes in vitro, in presence and in absence of an exogenous metabolizing system S9 rat liver. The treatment was done using different compound concentrations up to cytotoxic doses. The concentrations tested ranged between 12.5 to 62.5microg/ml of BADGE, 12.5 to 62.5microg/ml of first BADGE hydrolysis product (BADGE.H(2)O), 25.0 to 100.0microg/ml of second BADGE hydrolysis product (BADGE.2H(2)O) and 6.25 to 50.0microg/ml of BADGE.2HCl. These compounds are able to induce both cytotoxic and genotoxic effects, as revealed by the increases observed in cytokinesis block proliferation index (CBPI) and in micronuclei (MN) frequencies, respectively.     

Pyrophosphate-bridged complexes with picomolar toxicity

Recently, we have observed the emergence of a new series of pyrophosphate-bridged coordination complexes. Such complexes have been prepared by overcoming the ready hydrolysis of the pyrophosphate moiety. To date, no exploration has been conducted on the cytotoxicity of such complexes. Three pyrophosphate-bridged complexes, namely {[Ni(phen)₂]₂(μ-P₂O₇)}·27H₂O, {[Cu(phen)(H₂O)]₂(μ-P₂O₇)}·8H₂O and {[Co(phen)₂]₂(μ-P₂O₇)}·6MeOH, (where phen is 1,10′-phenanthroline) were chosen for their comparative structural similarities and suitable aqueous solubility. Cytotoxicity studies in the adriamycin-resistant ovarian cancer cell line A2780/AD demonstrated highly significant efficacy, with values as low as 160 pM for the cobalt complex at 72 h. The underlying mechanism for such exceptional toxicity is investigated focusing on DNA interactions, topoisomerase I enzyme inhibition and oxidative stress (followed by intracellular glutathione levels). The role of hydrolysis in uptake and toxicity is also explored (followed by electronic absorption spectroscopy, ³¹P NMR, and confocal microscopy) and the complexes are compared to cisplatin controls. Overall a clear picture of the extraordinary toxicity emerged. The results demonstrate a new class of prodrugs with significant potential for future development for the treatment of drug-resistant cancer cell lines.     

Pre-treatment of cattle semen or oocytes with purified milk osteopontin affects in vitro fertilization and embryo development

This study was designed to investigate the effects of pre-incubating cattle spermatozoa or matured oocytes with purified osteopontin (OPN) from cattle milk on fertilization in cattle and embryonic development in vitro. There were two different experiments, semen from six mature Holstein bulls (Bos Taurus) was frozen with different concentrations of OPN (0, 1, 10, 100 μg/mL). Matured cattle oocytes were also pre-treated with OPN (0, 10, 100 μg/mL). In both experiments, pre-treated oocytes or frozen semen, was processed for in vitro fertilization and embryo development. Significantly more oocytes were fertilized when using frozen semen with 10 μg/mL OPN (bull 2 = 85 ± 4% and bull 5 = 78 ± 4%) than without OPN (bull 2 = 75 ± 4% and bull 5 = 69 ± 4%). Those bulls also had increase in cleavage and embryo development (bull 2 = 85 ± 3%, 41 ± 1.9%; bull 5 = 76 ± 2%, 37 ± 1.8%) compared with control (bull 2 = 75 ± 3%, 30 ± 2%; bull 5 = 68 ± 2%, 29 ± 2%). Incubating matured oocytes in 10 μg/mL OPN (87 ± 3%) and 100 μg/mL OPN (88 ± 3%) significantly increased fertilization than control (73 ± 3%). OPN also improve cleavage, and embryo development in treatments with 10 μg/mL OPN (82.7 ± 1.3%; 31.7 ± 1.4%) and 100 μg/mL OPN (85.8 ± 1.3%; 33.8 ± 1.5%) when compared with control (74.1 ± 1.3%; 24.2 ± 1.2%). These data suggest that both, spermatozoa from some bulls and oocytes may associate with OPN, suggesting a facilitory role on in vitro fertilization and embryo development.     

Corticosteroids inhibit prostaglandin release from perfused mesenteric blood vessels of rabbit and from perfused lungs of sensitized guinea pig

Infusion of norephinephrine (NE) (1 – 3 μg/ml/min) into the isolated mesenteric vascular preparation of rabbit resulted in a rise in perfusion pressure, which was associated with the release of a prostaglandin E-like substance (PGE) at a concentration of 2.81 ± 0.65 ng/ml in terms of PGE₂. Indomethacin (3 μg/ml) abolished the NE-induced release of PGE. Arachidonic acid (0.2 μg/ml) in the presence of indomethacin did not restore the NE-induced release of PGE. Hydrocortisone (10 – 30 μg/ml) and dexamethasone (2 – 5 μg/ml) also inhibited the NE-induced release of PGE. The inhibitory action of both corticosteroids was abolished by arachidonic acid (0.2 μg/ml). Antigen-induced release of a prostaglandin-like substance(PGs) (43.1 ± 3.8 ng/ml in terms of PGE₂ and a rabbit aorta contracting substance (RCS) from perfused lungs of sensitized guinea pigs was completely abolished by indomethacin (5 μg/ml) or by hydrocortisone (100 μg/ml). Indomethacin, however, increased histamine release up to 280% of the control level, which was 470 ± 54 ng/ml, while hydrocortisone diminished histamine release down to 30% of the control level. A superimposed infusion of arachidonic acid (1 μg/ml) into the pulmonary artery reversed the hydrocortisone-induced blockade of the release of RCS and PGs. It may be concluded that corticosteroids neither inhibit prostaglandin synthetase nor influence prostaglandin transport through the membranes but they do impair the availability of the substrate for the enzyme.     

Corticosteroids inhibit prostaglandin release from perfused mesenteric blood vessels of rabbit and from perfused lungs of sensitized guinea pig

Infusion of norephinephrine (NE) (1 – 3 μg/ml/min) into the isolated mesenteric vascular preparation of rabbit resulted in a rise in perfusion pressure, which was associated with the release of a prostaglandin E-like substance (PGE) at a concentration of 2.81 ± 0.65 ng/ml in terms of PGE₂. Indomethacin (3 μg/ml) abolished the NE-induced release of PGE. Arachidonic acid (0.2 μg/ml) in the presence of indomethacin did not restore the NE-induced release of PGE. Hydrocortisone (10 – 30 μg/ml) and dexamethasone (2 – 5 μg/ml) also inhibited the NE-induced release of PGE. The inhibitory action of both corticosteroids was abolished by arachidonic acid (0.2 μg/ml). Antigen-induced release of a prostaglandin-like substance (PGs) (43.1 ± 3.8 ng/ml in terms of PGE₂ and a rabbit aorta contracting substance (RCS) from perfused lungs of sensitized guinea pigs was completely abolished by indomethacin (5 μg/ml) or by hydrocortisone (100 μg/ml). Indomethacin, however, increased histamine release up to 280% of the control level, which was 470 ± 54 ng/ml, while hydrocortisone diminished histamine release down to 30% of the control level. A superimposed infusion of arachidonic acid (1 μg/ml) into the pulmonary artery reversed the hydrocortisone-induced blockade of the release of RCS and PGs. It may be concluded that corticosteroids neither inhibit prostaglandin synthetase nor influence prostaglandin transport through the membranes but they do impair the availability of the substrate for the enzyme.     

Highly hydroxylated or γ-cyclodextrin-bicapped water-soluble derivative of fullerene: The antioxidant ability assessed by electron spin resonance method and β-carotene bleaching assay

Antioxidant ability of the water-soluble derivative of fullerene (C60), prepared by high-degree hydroxylation [C60-(OH)₃₂·8H₂O] or C60/γ-cyclodextrin (1:2 mol/mol) clathrate formation [C60/(γ-CD)₂], was assessed by electron spin resonance method and β-carotene bleaching assay. These C60 derivatives have an ability to diminish a 1:2:2:1 quartet ESR spectrum attributed to hydroxyl radicals (OH) as shown by DMPO-spin trap/ESR method. Meanwhile, a singlet radical-signal different from OH-attributed signals increased in a manner dependent on concentrations of C60-(OH)₃₂·8H₂O. This might suggest that C60-(OH)₃₂·8H₂O scavenges OH owing to dehydrogenation of C60-(OH)₃₂·8H₂O, and is simultaneously oxidized to a stable radical species, which may be a dehydrogenated fullerenol radical (C60-O). Furthermore, these water-soluble derivatives of C60 suppressed fading of yellowish color characteristic of intact β-carotene in β-carotene bleaching assay. Antioxidant abilities of these derivatives were assessed as retention of yellowish color (viz absorbance at 470 nm) for 180 min. Namely, β-carotene-attributed chromaticity (% relative absorbance at 470 nm compared with the control) after 180 min was 69% for C60-(OH)₃₂·8H₂O (400 μM: C60-eq.), and 32% for C60/(γ-CD)₂ (400 μM: C60-eq.), whereas it was 6% for l(+)-ascorbic acid (400 μM) which is hydrophilic, and 85% for (±)-α-tocopherol (400 μM) which is lipophilic, respectively. Thus C60-(OH)₃₂·8H₂O and C60/(γ-CD)₂ can scavenge OH, and have a distinct antioxidative activity in the aqueous system containing linoleic acid which is abundantly contained in the cell membrane together with other unsaturated lipids. These C60 derivatives have a potential to protect the cell membrane from oxidative stress due to OH.     

Medium optimization for the production of a novel bioflocculant from Halomonas sp. V3a′ using response surface methodology

The novel exopolysaccharide bioflocculant HBF-3 is produced by Halomonas sp. V3a′, which is a mutant strain of the deep-sea bacterium Halomonas sp. V3a. Response surface methodology (RSM) was employed to optimize the production medium for increasing HBF-3 production. Using a Plackett–Burman experimental design to aid in the first step of optimization, edible glucose, MgSO₄·7H₂O, and NH₄Cl were found to be significant factors affecting HBF-3 production. To determine the optimal concentration of each significant variable, a central composite design was employed. Based on response surface and canonical analysis, the optimum concentrations of the critical components were obtained as follows: edible glucose, 16.14 g/l; MgSO₄·7H₂O, 2.73 g/l; and NH₄Cl, 1.97 g/l. HBF-3 production obtained by using the optimized medium was 4.52 g/l, which was in close agreement with the predicted value of 4.55 g/l. By scaling up fermentation from flask to fermenter, HBF-3 production was further increased to 5.58 g/l.     

Butanol-extracted lipoteichoic acid induces in vivo leukocyte adhesion

Lipoteichoic acid (LTA), an immunostimulatory component of the cell walls of Gram positive bacteria, has pro-inflammatory effects in vitro and in vivo. However, one in vivo study concluded that LTA had no noticeable effects on leukocyte recruitment. In this study we investigated the effects of highly purified LTA, prepared by butanol extraction (Bu-LTA) at room temperature, on in vivo leukocyte adhesion. Using intravital microscopy we measured adhesion of leukocytes in mesenteric post-capillary venules of rats and mice. Topical superfusion of Bu-LTA (1 μg/ml) in rats significantly (p < 0.05) increased adhesion within 30 min. By contrast, hot phenol-extracted LTA did not increase adhesion. Alkaline hydrolysis of Bu-LTA removed alanine residues and prevented adhesion. Also, pre-administration of anti-rat β₂-integrin antibody abolished Bu-LTA-induced adhesion. Finally, intraperitoneal injection of Bu-LTA (100 μg/ml) into mice also significantly (p < 0.01) increased leukocyte adhesion measured at 60 min. In conclusion, Bu-LTA with intact alanine residues promotes β₂-integrin-dependent leukocyte adhesion in vivo.     

Assay of 2-naphthol in human urine by high-performance liquid chromatography

This paper describes a novel liquid chromatographic method for the quantitation of 2-naphthol in human urine. Urine samples were extracted after enzymatic hydrolysis of glucuronides and sulfates; 2-naphthol was then separated using reversed-phase high-performance liquid chromatography. The corresponding detection limits were 0.04 ng/ml for the standard sample in acetonitrile and 0.13 ng/ml for urine samples. The level of urinary 2-naphthol in 100 Korean shipyard workers was analyzed using this new method. The level ranged from 0.21 ng/ml (0.26 μmol/mol creatinine) to 34.19 ng/ml (59.11 μmol/mol creatinine), and the mean±standard deviation was 5.08 ng/ml (6.60 μmol/mol creatinine)±5.75 ng/ml (9.22 μmol/mol creatinine). The mean±standard deviation of urinary 2-naphthol level of smokers, 7.03 ng/ml (8.49 μmol/mol creatinine)±6.16 ng/ml (10.23 μmol/mol creatinine), was significantly higher than that of non-smokers, 2.49 ng/ml (4.10 μmol/mol creatinine)±3.92 ng/ml (7.03 μmol/mol creatinine).     

Acid hydrolysis of sugarcane bagasse for lactic acid production

In order to use sugarcane bagasse as a substrate for lactic acid production, optimum conditions for acid hydrolysis of the bagasse were investigated. After lignin extraction, the conditions were varied in terms of hydrochloric (HCl) or sulfuric (H₂SO₄) concentration (0.5–5%, v/v), reaction time (1–5 h) and incubation temperature (90–120 °C). The maximum catalytic efficiency (E) was 10.85 under the conditions of 0.5% of HCl at 100 °C for 5 h, which the main components (in g l⁻¹) in the hydrolysate were glucose, 1.50; xylose, 22.59; arabinose, 1.29; acetic acid, 0.15 and furfural, 1.19. To increase yield of lactic acid production from the hydrolysate by Lactococcus lactis IO-1, the hydrolysate was detoxified through amberlite and supplemented with 7 g l⁻¹ of xylose and 7 g l⁻¹ of yeast extract. The main products (in g l⁻¹) of the fermentation were lactic acid, 10.85; acetic acid, 7.87; formic acid, 6.04 and ethanol, 5.24.     

Effect of renoguanylin on hydrogen/bicarbonate ion transport in rat renal tubules

Renoguanylin (REN) is a recently described member of the guanylin family, which was first isolated from eels and is expressed in intestinal and specially kidney tissues. In the present work we evaluate the effects of REN on the mechanisms of hydrogen transport in rat renal tubules by the stationary microperfusion method. We evaluated the effect of 1 μM and 10 μM of renoguanylin (REN) on the reabsorption of bicarbonate in proximal and distal segments and found that there was a significant reduction in bicarbonate reabsorption. In proximal segments, REN promoted a significant effect at both 1 and 10 μM concentrations. Comparing control and REN concentration of 1 μM, JHCO₃⁻, nmol cm^− 2 s^− 1 − 1,76 ± 0,11_control × 1,29 ± 0,08_{REN 10 μM}; P < 0.05, was obtained. In distal segments the effect of both concentrations of REN was also effective, being significant e.g. at a concentration of 1 μM (JHCO₃⁻, nmol cm^− 2 s⁻ 1 − 0.80 ± 0.07_control × 0.60 ± 0.06_{REN 1 μM}; P < 0.05), although at a lower level than in the proximal tubule. Our results suggest that the action of REN on hydrogen transport involves the inhibition of Na⁺/H⁺exchanger and H⁺-ATPase in the luminal membrane of the perfused tubules by a PKG dependent pathway.     

Culture medium improvement for Isaria fumosorosea submerged conidia production

Submerged conidia and blastospores of the entomopathogenic fungus Isaria fumosorosea are produced in several liquid culture media. However, yields and the ecological fitness of these propagules vary according to culture media composition. In most culture media, hyphae, blastospores and submerged conidia are white but we found that in some media they develop a brown pigmentation. A dark pigment was extracted from brown-pigmented propagules and analyzed by IR spectroscopy. Adsorption bands coincided to those characteristics of melanins.Hadamard's matrices were employed in order to increase submerged conidia yields and brown pigmentation of fungal propagules. Media containing 20–30 mg/l of FeSO₄·7H₂O and 6–12 mg/l of CuSO₄·5H₂O allowed reaching the highest pigmentation (9 in a hedonic scale). A maximal concentration of submerged conidia of 1.0 (±1.2) × 10¹² cell/l was achieved after 120 h of liquid culture in a improved culture medium, containing 25 ml/l of Polyethylene glycol (MW 200), substance which enhanced submerged conidia production, reducing free mycelia or mycelial pellets formation. In the improved medium, it was estimated that more than 60% of produced biomass corresponded to submerged conidia and blastospores, while in other media, mycelia were the main product (80–97%).     

NF-κB inhibitory activity of cyclitols isolated from Hancornia speciosa

Hancornia speciosa Gomes (Apocynaceae) is a Brazilian plant traditionally employed to treat inflammatory conditions, among other uses. The chemopreventive effect of an ethanol extract from H. speciosa leaves (EHS) was evaluated in a battery of in vitro tests [inhibition of aromatase, NF-κB and ornithine decarboxylase (ODC), antioxidant response elements (ARE) induction and cell proliferation assays]. Bioassay-directed fractionation of EHS following by inhibition of 12-O-tetradecanoyl-13-acetate (TPA)-mediated NF-kB activation led to the isolation of the cyclitols quinic acid (1) (85.0±12.3 μM) and l-(+)-bornesitol (2) (IC₅₀=27.5±3.8 μM), along with rutin (26.8±6.3 μM). Based on these lead compounds, the cyclitols per-O-acetyl-1l-(+)-bornesitol (3) (IC₅₀=38.4±6.2 μM), myo-inositol (4) (>180.2 μM), scyllo-inositol (5) (83.0±13.7 μM) and β-d-galactoside-myo-inositol (6) (52.4±8.4 μM) were evaluated in the assay, but found to be somewhat less active than 1 and 2. None of the compounds was active in the ARE, aromatase or ODC assays and did not inhibit proliferation of MCF-7, LNCaP, HepG2 or LU-1 cell lines at a final concentration of 20 μg/ml (equivalent to 104.07–32.76 μM).This work identifies l-(+)-bornesitol, quinic acid and rutin as NF-κB inhibitors of H. speciosa and suggests cyclitols, in addition to myo-inositol, are potentially useful as chemopreventive agents.     

The Determination of Phosphorus in Haemophilus influenzae Type b Conjugate Vaccines by Inductively Coupled Plasma-Atomic Emission Spectrometry

This study describes a method for the determination of phosphorus in lyophilized Haemophilus influenzae type b conjugate vaccines by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The concentration of polysaccharide is directly related to the concentration of phosphorus as measured in the laboratory. Phosphorus is present in the polyribosyl-ribitol phosphate (PRP) group of the Haemophilus influenzae type b conjugate vaccine. The repeating unit of PRP is 3-B-D ribose[1-1]ribitol-5-phosphate. Phosphorus in the final container is measured in μ g per dose. The amount of PRP is calculated from this and reported in μ g per dose. The Haemophilus influenzae type b conjugate vaccine was analyzed for phosphorus content within the range of 1·34 to 2·02 μg phosphorus per ml. The relative difference of phosphorus concentrations determined by the ICP-AES method from the phosphorus concentrations determined by the traditional colorimetric molybdate method ranged from 2·2 to 10·6%. Phosphorus spike recovery for the vaccine ranged from 93 to 99% (1·93±0·13 μ g P/ml). The phosphorus determination of NIST SRM 3139 phosphorus spectrometric solution differed by 3·0% from the certified phosphorus value (10·00 mg P/ml).     

Solid-phase extraction and high-performance liquid chromatographic determination of tamoxifen and its major metabolites in plasma

Tamoxifen (TAM) is a triphenylethylene anti-oestrogen, commonly used in the treatment of breast cancer. Patients receiving tamoxifen therapy may experience both de novo and acquired resistance. As one of the mechanisms for this may be extensive peripheral bio-transformation of tamoxifen, there has been considerable interest in the pharmacokinetics and metabolism of tamoxifen. A reversed-phase high-performance liquid chromatography separation has been developed to determine the levels of tamoxifen and its major metabolites in human plasma. The method is highly sensitive (2 ng/ml) and selective for tamoxifen, cis-tamoxifen (CIS), 4-hydroxytamoxifen (4-OH) and desmethyltamoxifen (DMT). A μBondapak C₁₈ 10 μm column (30 cm × 3.9 mm I.D.) was used, with a mobile phase of methanol-1% triethylamine at pH 8 (89:11, v/v). Sample preparation was carried out using a C₂ (500 mg sorbent, 3 ml reservoirs) solid phase extraction method, and extraction efficiencies were approximately 60% for TAM and its metabolites. Accuracy and precision, as determined by spiking plasma samples with a mixture of tamoxifen and its metabolites, ranged from 85–110% (± 5–10%) at 1 μg/ml, 101–118% (± 8–20%) at 0.1 μg/ml and 111–168% (± 43–63%) at 0.01 μg/ml. Results from 59 patients show mean values of 54 ng/ml for 4-OH; 190 ng/ml for DMT; 93 ng/ml for TAM and 30 ng/ml for CIS (detected in three patients only). This methodology can be applied routinely to the determination of TAM and its metabolites in plasma from patients undergoing therapy.     

Response surface design for the optimization of enzymatic detection of mercury in aqueous solution using immobilized urease from vegetable waste

Soluble and alginate immobilized urease was utilized for detection and quantitation of mercury in aqueous samples. Urease from the seeds of pumpkin, being a vegetable waste, was extracted and purified to apparent homogeneity (sp. activity 353 U/mg protein; A₂₈₀/A₂₆₀ = 1.12) by heat treatment at 48 ± 0.1 °C and gel filtration through Sephadex G-200. Homogeneous enzyme preparation was immobilized in 3.5% alginate leading to 86% immobilization, no leaching of enzyme was found over a period of 15 days at 4 °C. Urease catalyzed urea hydrolysis by soluble and immobilized enzyme revealed a clear dependence on the concentration of Hg²⁺. Inhibition caused by Hg²⁺ was non-competitive (K_i = 1.2 × 10⁻¹ μM for soluble and 1.46 × 10⁻¹ μM for alginate immobilized urease.). Time-dependent inhibition both in presence and in absence of Hg²⁺ ion revealed a biphasic inhibition in activity. For optimization of this process response surface methodology (RSM) was utilized where two-level-two-full factorial (2²) central composite design (CCD) has been employed. The regression equation and analysis of variance (ANOVA) were obtained using MINITAB^® 15 software. Predicted values thus obtained were closed to experimental value indicating suitability of the model. 3D response surface plot, iso-response contour plot and process optimization curve were helpful to predict the results by performing only limited set of experiments.     

Determination of lamotrigine in human serum by liquid chromatography

A rapid high-performance liquid chromatographic method was developed using a short silica column (30 mm×4.6 mm) with an aqueous methanol mobile phase consisting of methanol–water–NH₄H₂PO₄ (94:5.96:0.04) adjusted to a final apparent pH of 5.0 and pumped at a flow-rate of 1 ml/min. Ultraviolet detection was carried out at a wavelength of 280 nm, and serum samples were prepared for HPLC analysis by extraction into dichloromethane after basification. Lamotrigine was eluted at 0.96 min. Within-day variation of the method was 4.46% at 0.75 μg/ml and 2.37% at 6.0 μg/ml, and day-to-day variation was 9.10% at 0.75 μg/ml and 7.28% at 6.0 μg/ml.     

Simultaneous determination of the camptothecin analogue CPT-11 and its active metabolite SN-38 by high-performance liquid chromatography: application to plasma pharmacokinetic studies in cancer patients

CPT-11 {I; 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin} is a new anticancer agent currently under clinical development. A sensitive high-performance liquid chromatographic assay suitable for the simultaneous determination of I and its active metabolite SN-38 (II) in human plasma, and their preliminary clinical pharmacokinetics, are described. Plasma samples were processed using a solid-phase (C₁₈) extraction step allowing mean recoveries of I, II and the internal standard camptothecin (III) of 84, 99 and 72%, respectively. The extracts were chromatographed on a C₁₈ reversed-phase column with a mobile phase composed of acetonitrile, phosphate buffer and heptanesulphonic acid, with fluorescence detection. The calibration graphs were linear over a wide range of concentrations (1 ng/ml–10 μg/ml), and the lower limit of determination was 1 ng/ml for both I and II. The method showed good precision: the within-day relative standard deviation (R.S.D.) (5–1000 ng/ml) was 13.0% (range 4.9–19.4%) for I and 12.8% (6.7–19.1%) for II; the between-day R.S.D. (5–10 000 ng/ml was 7.9% (5.4–17.5%) for I and 9.7% (3.5–15.1%) for II. Using this assay, plasma pharmacokinetics of both I and II were simultaneously determined in three patients receiving 100 mg/m² I as a 30-min intravenous infusion. The mean peak plasma concentration of I at the end of the intravenous infusion was 2400 ± 285 ng/ml (mean ± standard error of the mean). Plasma decay was triphasic with half-lives α, β and γ of 5.4 ± 1.8 min, 2.5 ± 0.5 h and 20.2 ± 4.6 h, respectively. The volume of distribution at steady state was 105 ± 15 l/m², and the total body clearance was 12.5 ± 1.9 l/h · m². The maximum concentrations of the active metabolite II reached 36 ± 11 ng/ml.     

Effects of uterine stimulant drugs on prostacyclin production by the pregnant rat myometrium. I. Oxytocin, bradykinin and PGF2α

The release of prostacyclin from chopped myometrial fractions of 18–20 day pregnant rats was assayed by inhibition of ADP-induced aggregation of citrated rabbit platelet-rich plasma. Preincubation of myometrial tissue with oxytocin 10 mU/ml increased prostacyclin generation from 2.25 ± 0.48 (control) to 3.75 ± 0.73 ng/mg over 15 minutes. Bradykinin 20 μg/ml also caused a significant increase in myometrial prostacyclin output from 2.26 ± 0.19 to 4.26 ± 0.64 ng/mg. PGF_2α 1 μg/ml did not increase prostacyclin release significantly. Pretreatment of myometrial tissue with the phospholipase inhibitor mepacrine significantly reduced the peptide-stimulated release of prostacyclin. The results suggest that prostacyclin production may play an important role in modulating the actions of oxytocin and bradykinin in the pregnant rat myometrium.     

Cytotoxic activity, X-ray crystal structures and spectroscopic characterization of cobalt(II), copper(II) and zinc(II) coordination compounds with 2-substituted benzimidazoles

Herein we present the synthesis, structural and spectroscopic characterization of coordination compounds of cobalt(II), copper(II) and zinc(II) with 2-methylbenzimidazole (2mbz), 2-phenylbenzimidazole (2phbz), 2-chlorobenzimidazole (2cbz), 2-benzimidazolecarbamate (2cmbz) and 2-guanidinobenzimidazole (2gbz). Their cytotoxic activity was evaluated using human cancer cell lines, PC3 (prostate), MCF-7 (breast), HCT-15 (colon), HeLa (cervic-uterine), SKLU-1 (lung) and U373 (glioblastoma), showing that the zinc(II) and copper(II) compounds [Zn(2mbz)₂Cl₂]·0.5H₂O, [Zn(2cmbz)₂Cl₂]·EtOH, [Cu(2cmbz)Br₂]·0.7H₂O and [Cu(2gbz)Br₂] had significant cytotoxic activity. The isostructural cobalt(II) complexes showed not significant activity. The cytotoxic activity is related to the presence of halides in the coordination sphere of the metal ion. Recuperation experiments with HeLa cells, showed that the cells recuperated after removing the copper(II) compounds and, on the contrary, the cells treated with the zinc(II) compounds did not. These results indicate that the mode of action of the coordination compounds is different.