Surface contamination with ten antineoplastic drugs in 83 Canadian centers.

PURPOSE: The aim of this study was to monitor environmental contamination by 10 antineoplastic drugs in Canadian oncology pharmacy and patient care areas. The secondary objective was to explore the impact of factors that may explain contamination. METHODS: Twelve standardized sites were sampled in each center (six in the pharmacy and six in patient care areas). Each sample was prepared to allow quantification of seven antineoplastic drugs (cyclophosphamide, ifosfamide, methotrexate, cytarabine, gemcitabine, 5-fluorouracil, irinotecan) by UPLC-MS-MS. Docetaxel, paclitaxel and vinorelbine were also detected, but not quantified due to sensibility limitations. The impact of some factors was evaluated compared with a Kolmogorov-Smirnov test for independent samples. RESULTS: Eighty-three Canadian centers were recruited in 2017. A total of 953 surfaces were sampled, 495 in pharmacy and 458 in patient care areas. Cyclophosphamide was most often found on surfaces (36% of samples positive, 75th percentile 0.0040 ng/cm2). The arm rest (81.7% of samples positive for at least one antineoplastic drug), the front grille inside the hood (78.3%) and the floor in front of the hood (61.4%) were more frequently contaminated. Centers who prepared more antineoplastic drugs per year had higher concentration on different surfaces ( p < 0.0001). CONCLUSION: Despite growing awareness and implementation of new safe handling guidelines, healthcare centers' surfaces remain contaminated with traces of many antineoplastic drugs. The use of personal protective equipment remains indisputable. Performing an annual monitoring remains a good indicator to monitor trends over time and to compare with similar centers.

2D Supramolecular networks of dibenzonitrilediacetylene on Ag(111) stabilized by intermolecular hydrogen bonding.

The two-dimensional (2D) surface-directed self-assembly of dibenzonitrile diacetylene (DBDA) on Ag(111) under ultrahigh vacuum (UHV) conditions was investigated by combining scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and theoretical simulations based on density functional theory (DFT) calculations. The molecule consists of two benzonitrile groups (-C6H4-C[triple bond, length as m-dash]N) on each side of a diacetylene (-C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C-) backbone. The terminating nitrile (-C[triple bond, length as m-dash]N) groups at the meta position of the phenyl rings lead to cis and trans stereoisomers. The trans isomer is prochiral and can adsorb in the R or S configuration, leading to the formation of enantiomeric self-assembled networks on the surface. We identify two simultaneously present supramolecular networks, termed parallel and chevron phases, as well as a less frequently observed butterfly phase. These networks are formed from pure R (or S) domains, racemic mixtures (RS), and cis isomers, respectively. Our complementary data illustrates that the formation of the 2D supramolecular networks is driven by intermolecular hydrogen bonding between nitrile and phenyl groups (-C[triple bond, length as m-dash]NH-C6H3). This study illustrates that the molecular arrangement of each network depends on the geometry of the isomers. The orientation of the nitrile group controls the formation of the most energetically stable network via intermolecular hydrogen bonding.

A descriptive analysis of first trimester urinary concentrations of 14 bisphenol analogues in the MIREC Canadian pregnancy cohort.

BACKGROUND: Concern over the health effects of BPA, particularly for the developing fetus, has led to an increasing use of bisphenol analogues in industrial and consumer products, which may be as hormonally active as BPA. Biomonitoring data for many bisphenol analogues, especially in pregnant populations, are limited. METHODS: We measured concentrations of 14 bisphenol analogues in 1st trimester urine samples (n = 1851) from the Maternal-Infant Research on Environmental Chemicals (MIREC) Canadian pregnancy cohort (2008-2011). We examined patterns of exposure according to sociodemographic and sampling characteristics as well as occupation and frequency of consumption of canned fish within the previous 3 months. RESULTS: BPA was detected in 89% of participants with a specific gravity standardized geometric mean concentration of 0.990 µg/L. Biphenol 4,4' (BP 4,4'), 4,4'-dihydroxydiphenyl ether (DHDPE), and bisphenol E (BPE) were detected in >97% of participants. Bisphenol F (BPF) and bisphenol S (BPS) were detected in >60% of participants. Specific gravity standardized geometric mean concentrations of these 5 compounds ranged from 0.024 to 0.564 µg/L. Nine bisphenol analogues were detected in <9% of participants. Concentrations of BP 4,4', DHDPE, and BPE were higher in younger women and those with higher pre-pregnancy BMI, lower household income, lower education, and among smokers. We found a similar pattern of differences in BPF for age, education, and smoking status while BPS similarly differed across categories of pre-pregnancy BMI. Participants who were unemployed or working in the service industry had higher molar sum of 7 bisphenol analogues than those working in healthcare, education, or an office setting. Canned fish consumption was not related to bisphenol analogue concentrations. CONCLUSION: BP 4,4', DHDPE, BPE, BPF, and BPS were highly detected in 1st trimester urine samples in this large pan-Canadian pregnancy cohort. This suggests widespread exposure to these analogues around 2008-2011 and warrants further investigation into associations with health outcomes.

Variety and variability of glycosidase activities in an Oenococcus oeni strain collection tested with synthetic and natural substrates.

AIMS: To evaluate the capacity of Oenococcus oeni strains to release aroma compounds from glycosylated precursors by measuring glycosidase activities with both synthetic and natural substrates. METHODS AND RESULTS: Five glycosidase activities were investigated in 47 O. oeni strains using synthetic substrates. This screening revealed that activity levels vary considerably, not only for each strain (depending on the substrate tested), but also between strains. Fifteen strains exhibiting different activity profiles were further analysed using natural substrates extracted from both untoasted and toasted oak. In the latter, various amounts of aromatic compounds were measured, thus confirming the specific potentials of the selected strains, but the results were different from those obtained using synthetic substrates. In addition, the use of toasted wood extracts significantly increased the release of wood aromas, which minimized differences between strains. CONCLUSIONS: The capability of O. oeni to hydrolysate glycoconjugate aroma precursors is strain-dependent and variable, depending on the substrate. SIGNIFICANCE AND IMPACT OF THE STUDY: Instead of synthetic substrates, natural aroma precursors should be used for an adequate evaluation of the glycosidase potential of O. oeni.

The F13 residue is critical for interaction among the coat protein subunits of papaya mosaic virus.

Papaya mosaic virus (PapMV) coat protein (CP) in Escherichia coli was previously showed to self-assemble in nucleocapsid-like particles (NLPs) that were similar in shape and appearance to the native virus. We have also shown that a truncated CP missing the N-terminal 26 amino acids is monomeric and loses its ability to bind RNA. It is likely that the N-terminus of the CP is important for the interaction between the subunits in self-assembly into NLPs. In this work, through deletion and mutation analysis, we have shown that the deletion of 13 amino acids is sufficient to generate the monomeric form of the CP. Furthermore, we have shown that residue F13 is critical for self-assembly of the CP subunits into NLPs. The replacement of F13 with hydrophobic residues (L or Y) generated mutated forms of the CP that were able to self-assemble into NLPs. However, the replacement of F13 by A, G, R, E or S was detrimental to the self-assembly of the protein into NLPs. We concluded that a hydrophobic interaction at the N-terminus is important to ensure self-assembly of the protein into NLPs. We also discuss the importance of F13 for assembly of other members of the potexvirus family.

Structure of the glycan chain from the surface layer glycoprotein of Clostridium thermohydrosulfuricum L77-66.

The thermophilic eubacterium Clostridium thermohydrosulfuricum L77-66 is covered by a crystalline surface layer composed of identical glycoprotein subunits which are arranged in a hexagonal lattice with centre-to-centre spacings of approx. 14.3 nm. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of cell wall preparations showed the presence of several broadened, carbohydrate-containing bands in a molecular mass range of 90 to 200 kDa. A total carbohydrate content of approx. 14% was determined in the purified surface layer glycoprotein. Chemical deglycosylation of this material by trifluoromethanesulfonic acid resulted in the disappearance of the complex banding pattern. Only a single band with a molecular mass of 82 kDa remained visible upon Coomassie staining. After proteolytic digestion of the surface layer glycoprotein a single glycopeptide fraction with an apparent molecular mass of approx. 25 kDa was obtained by gel filtration. Composition analysis, methylation, periodate oxidation and a combination of homonuclear and 1H-detected heteronuclear shift-correlated nuclear magnetic resonance experiments established the following structure for the glycan chain of the surface layer glycoprotein.

Common sequence variants of lipoprotein lipase: standardized studies of in vitro expression and catalytic function.

We have assessed the functional activity of three common sequence variants of human lipoprotein lipase (LPL). Two of these, Asn291Ser and Asp9Asn arise from missense mutations while the third, Ser447Ter, derives from a nonsense mutation, truncating LPL by two residues. As previous in vitro studies have produced conflicting results, we have re-analyzed the catalytic function of these variants using the COS cell transfection system, under optimized and standardized experimental protocols. We found the Asn291Ser variant to manifest with a decrease in catalytic activity (57% of normal) due to a reduction in secretion and stability of the active homodimeric form. The Asp9Asn variant also showed a significant decrease in catalytic activity (85% of normal), but this was found to be due to a decreased rate of secretion only, as the homodimeric form was stable. The findings for these mutants contrasted with those of the Ser447Ter truncation variant which proved to be catalytically normal; this variant also manifested normal homodimer stability. The truncated variant did however, present with a higher total secreted mass level (131%) than control LPL. This was most likely due to enhanced secretion of the monomeric form. None of these mutations exhibited defects in binding affinity to cell surface proteoglycans. Each of these variants deviated significantly from normal as regards to their secreted activity or mass levels in the COS cell transfection system.

Backbone and methyl dynamics of the regulatory domain of troponin C: anisotropic rotational diffusion and contribution of conformational entropy to calcium affinity.

The N-terminal domain (residues 1 to 90) of chicken skeletal troponin C (NTnC) regulates muscle contraction upon the binding of a calcium ion to each of its two calcium binding loops. In order to characterize the backbone dynamics of NTnC in the apo state (NTnC-apo), we measured and carefully analyzed 15N NMR relaxation parameters T1, T2 and NOE at 1H NMR frequencies of 500 and 600 MHz. The overall rotational correlation time of NTnC-apo at 29.6 degrees C is 4.86 (+/-0.15) ns. The experimental data indicate that the rotational diffusion of NTnC-apo is anisotropic with a diffusion anisotropy, D parallel/D perpendicular, of 1.10. Additionally, the dynamic properties of side-chains having a methyl group were derived from 2H relaxation data of CH2D groups of a partially deuterated sample. Based on the dynamic characteristics of TnC, two different levels of "fine tuning" of the calcium affinity are presented. Significantly lower backbone order parameters (S2), were observed for calcium binding site I relative to site II and the contribution of the bond vector fluctuations to the conformational entropy of sites I and II was calculated. The conformational entropy loss due to calcium binding (DeltaDeltaSp) differs by 1 kcal/mol between sites I and II. This is consistent with the different dissociation constants previously measured for sites I and II of 16 microM and 1. 7 microM, respectively. In addition to the direct role of binding loop dynamics, the side-chain methyl group dynamics play an indirect role through the energetics of the calcium-induced structural change from a closed to an open state. Our results show that the side-chains which will be exposed upon calcium binding have reduced motion in the apo state, suggesting that conformational entropic contributions can be used to offset the free energy cost of exposing hydrophobic groups. It is clear from this work that a complete determination of their dynamic characteristics is necessary in order to fully understand how TnC and other proteins are fine tuned to appropriately carry out their function.

Insights into the mechanism of heterodimerization from the 1H-NMR solution structure of the c-Myc-Max heterodimeric leucine zipper.

The oncoprotein c-Myc (a member of the helix-loop-helix-leucine zipper (b-HLH-LZ) family of transcription factors) must heterodimerize with the b-HLH-LZ Max protein to bind DNA and activate transcription. It has been shown that the LZ domains of the c-Myc and Max proteins specifically form a heterodimeric LZ at 20 degreesC and neutral pH. This suggests that the LZ domains of the c-Myc and Max proteins are playing an important role in the heterodimerization of the corresponding gene products in vivo. Initially, to gain an insight into the energetics of heterodimerization, we studied the stability of N-terminal disulfide-linked versions of the c-Myc and Max homodimeric LZs and c-Myc-Max heterodimeric LZ by fitting the temperature-induced denaturation curves monitored by circular dichroism spectroscopy. The c-Myc LZ does not homodimerize (as previously reported) and the c-Myc-Max heterodimeric LZ is more stable than the Max homodimeric LZ at 20 degreesC and pH 7.0. In order to determine the critical interhelical interactions responsible for the molecular recognition between the c-Myc and Max LZs, the solution structure of the disulfide-linked c-Myc-Max heterodimeric LZ was solved by two-dimensional 1H-NMR techniques at 25 degreesC and pH 4.7. Both LZs are alpha-helical and the tertiary structure depicts the typical left-handed super-helical twist of a two-stranded parallel alpha-helical coiled-coil. A buried salt bridge involving a histidine on the Max LZ and two glutamate residues on the c-Myc LZ is observed at the interface of the heterodimeric LZ. A buried H-bond between an asparagine side-chain and a backbone carbonyl is also observed. Moreover, evidence for e-g interhelical salt bridges is reported. These specific interactions give insights into the preferential heterodimerization process of the two LZs. The low stabilities of the Max homodimeric LZ and the c-Myc-Max heterodimeric LZ as well as the specific interactions observed are discussed with regard to regulation of transcription in this family of transcription factors.

Quantification of the calcium-induced secondary structural changes in the regulatory domain of troponin-C.

The backbone resonance assignments have been completed for the apo (1H and 15N) and calcium-loaded (1H, 15N, and 13C) regulatory N-domain of chicken skeletal troponin-C (1-90), using multidimensional homonuclear and heteronuclear NMR spectroscopy. The chemical-shift information, along with detailed NOE analysis and 3JHNH alpha coupling constants, permitted the determination and quantification of the Ca(2+)-induced secondary structural change in the N-domain of TnC. For both structures, 5 helices and 2 short beta-strands were found, as was observed in the apo N-domain of the crystal structure of whole TnC (Herzberg O, James MNG, 1988, J Mol Biol 203:761-779). The NMR solution structure of the apo form is indistinguishable from the crystal structure, whereas some structural differences are evident when comparing the 2Ca2+ state solution structure with the apo one. The major conformational change observed is the straightening of helix-B upon Ca2+ binding. The possible importance and role of this conformational change is explored. Previous CD studies on the regulatory domain of TnC showed a significant Ca(2+)-induced increase in negative ellipticity, suggesting a significant increase in helical content upon Ca2+ binding. The present study shows that there is virtually no change in alpha-helical content associated with the transition from apo to the 2Ca2+ state of the N-domain of TnC. Therefore, the Ca(2+)-induced increase in ellipticity observed by CD does not relate to a change in helical content, but more likely to changes in spatial orientation of helices.

Bogorol A produced in culture by a marine Bacillus sp. reveals a novel template for cationic peptide antibiotics.

[figure: see text] Bogorol A (1), a novel peptide antibiotic active against MRSA and VRE, has been isolated from cultures of a marine Bacillus sp. collected in Papua New Guinea. The structure of bogorol A was elucidated by a combination of spectroscopic analyses and chemical degradation. Bogorol A illustrates a new structural template for "cationic peptide antibiotics".

Handedness effects in the detection of dichotically-presented words and emotions.

Left-handed and right-handed subjects were given two dichotic listening tasks using identical material. In one task, they were asked to determine whether or not a specific target word was present (verbal task). In the other task, subjects were asked to indicate whether or not one of the dichotically-competing words was spoken in a particular affective tone (emotion task). Overall, a right-ear advantage (REA) was found with the verbal task and a left-ear advantage (LEA) with the emotion task. Left-handers showed a slightly smaller REA than right-handers on the verbal task, but a slightly larger LEA on the emotion task. This finding suggests that left- and right-hemispheric functions are not related in a complementary fashion and that handedness effects for nonverbal tasks are different from those seen with verbal tasks. The emotional LEA was much larger for angry stimuli than for happy, sad, or neutral stimuli. Rather than providing evidence for a hemisphere by affective valence interaction, such results suggest a stimulus-specific effect.

Enigma of early receptor potential in fly eyes.

The early receptor potential (ERP) of fly photoreceptors R1-6 has been recorded in the blowfly Calliphora erythrocephala, and quantitatively analyzed. Photoconversion of the native visual pigment (P) into the meta-state (M) does not induce a measurable ERP. Photoconversion of M into P induces a biphasic ERP, presumably due to the slow thermal decay of intermediate N, recently discovered by Roebroek, Gagné and Stavenga (1989). The experimentally measured ERP's are interpreted with an RC-model which incorporates the time constant of the flash, the time constant of the thermal decay of intermediate N, the electrical properties of the photoreceptor cell and the charge displacements within the visual pigment molecules occurring upon photoconversion. The model satisfactorily describes the ERP for the M to P conversion by assuming that effectively 0.03 electron charges are moved across the cell membrane during conversion of the M to the N state and that 0.04 electron charges are moved in the opposite direction during conversion of N to P. The net 0.01 electron charge movement during conversion of P to M would, according to the simple RC-model, induce a measurable ERP, in conflict with the experimental results. The longstanding enigma of the ERP of fly photoreceptors appears largely but not completely resolved.

Compensation of the differential floating capacitance between dual microelectrodes.

A circuit for compensating the floating differential capacitance appearing between two recording microelectrodes is presented. It is shown how this floating capacitance can be neutralized so that current in any microelectrode can be injected without any significant crosstalk picked up by the other.

Bacterial-Mediated Induced Resistance in Cucumber: Beneficial Effect of the Endophytic Bacterium Serratia plymuthica on the Protection Against Infection by Pythium ultimum.

ABSTRACT The potential of the endophytic bacterium Serratia plymuthica strain R1GC4 in stimulating defense reactions in cucumber (Cucumis sativus) seedlings inoculated with the soilborne pathogen Pythium ultimum was explored at the cellular level. Bacterial treatment prior to Pythium inoculation resulted in less seedling disease development as compared with that in nontreated control plants, in which typical root symptoms were visible by 3 days after inoculation with the pathogen. Histological investigations of root samples revealed striking differences in the extent of plant defense reactions between bacterized and nonbacterized plants. These observations were further confirmed at the ultrastructural level with the demonstration that restriction of fungal colonization to the outermost root tissues of bacterized seedlings correlated with the deposition of enlarged callose-enriched wall appositions at sites of potential pathogen penetration and the accumulation of an osmiophilic material in the colonized areas. Hyphae of the pathogen, surrounded by this electron-opaque material, exhibited considerable changes including cytoplasm disorganization and, in many cases, loss of the protoplasm. However, labeling with the beta-1,4-exoglucanase resulted in a regular labeling of Pythium cell walls, even at a time when these walls were entirely coated by the osmiophilic material. This material was also found to infiltrate into the invading hyphae to form either an internal coating of the cell wall or a network of polymorphic droplets in the area previously occupied by the cytoplasm. Cytochemical investigations revealed that callose, pectin, and cellulose appeared in the wall appositions. In addition, glucosides, lipids, and phenolics were detected in the electron-dense aggregates forming the core of most wall appositions. Finally, galactose residues were among the minor polysaccharidic compounds detected in the wall appositions. Evidence is provided in this study showing that treatment with S. plymuthica sensitizes susceptible cucumber plants to react more rapidly and more efficiently to Pythium attack through the formation of physical and chemical barriers at sites of potential fungal entry.

Clonal deletion of some V beta+ T cells in peripheral lymphocytes from C57BL/6 mice infected with MHV3.

Mouse hepatitis virus type 3 infection is generally accompanied by a severe immune dysfunction involving thymic or splenic T cell subpopulations. We postulate that the peripheral lymphoid cell depletions were caused by a selective deletion of some V beta subsets of mature T cells, as observed with superantigens. We have examined the expression of V beta 6, V beta 8 and V beta 14 in T cell subpopulations from the spleen and lymph nodes of pathogenic L2-MHV3-infected C57BL/6 mice. Cytofluorometric study showed decreases in splenic V beta 8+, V beta 6+, and V beta 14+ T cell subpopulations at 72 hrs post-infection. Single positive CD4+ T cells were diminushed but not the CD8+ cells. In contrast, the various V beta splenic cell populations were not modified in mice infected with a non- pathogenic YAC-MHV3 variant. However, the V beta 8/CD4 ratio increased in splenic cells but decreased in lymphocytes from lymph nodes. The V beta 14/CD4 ratio decreased only in splenic cells while V beta 6/CD4 ratios were not modified. These results suggest that alterations in V beta cell populations may play a role in the L2-MHV3-induced immunodeficiency.

Nasal epithelial changes induced in piglets by acetic acid and by Bordetella bronchiseptica.

Research on atrophic rhinitis of pigs has shown that both Bordetella bronchiseptica infection and experimental treatment with acetic acid predispose the nasal mucosa to colonization with Pasteurella multocida. Gnotobiotic piglets aged 3 days were dosed intranasally with either B. bronchiseptica (n = 6) or acetic acid 1 per cent (n = 10) and killed at intervals up to the 4th day after treatment. Samples of the ventral turbinates were examined by light microscopy and scanning and transmission electron microscopy. Within 12 h acetic acid induced loss of cilia, oedema, focal cell exfoliations, mitochondrial swelling and inflammatory cell infiltration. Bordetella bronchiseptica induced only a limited oedema and loss of cilia. Colonization of cilia by the bacteria was observed 96 h after infection. We conclude that, although acetic acid and B. bronchiseptica do not induce the same modifications of the nasal respiratory epithelium, their action causes stagnation of nasal mucus, which results in a nasal environment favourable to colonization by Pasteurella multocida.

Effects of Pasteurella multocida toxin on the osteoclast population of the rat.

Pasteurella multocida type D toxin is a peptide shown to induce severe atrophic rhinitis in the pig as the result of an increased osteoclastic resorption of the ventral nasal turbinates. In the present study, the effects of the toxin on the histological, cytochemical and ultrastructural features of the osteoclast population of the rat were examined. Pasteurella multocida toxin induced atrophy of the ventral and dorsal nasal turbinates and thinning of the nasal bones. The number and size of the long bone metaphyseal osteoclasts were significantly increased, but not the number of nuclei per cell. Osteoclasts of toxin-treated rats had more developed clear zones and ruffled borders than those of the controls and their cytoplasmic vacuoles were more abundant and larger. We concluded that P. multocida toxin stimulates bone resorption by osteoclasts in the rat by increasing resorption activity and by increasing their number. Its action is not limited to the nasal turbinates but occurs also in the other bones, such as the long bones.

High-speed electromechanical shutter for vision research.

A low-cost and high-speed electromechanical shutter is described. The design makes use of a small magnet moving in a magnetic field and includes a specially developed electronic control for optimal operation. The opening and closing time of the shutter is below 200 microseconds with overall time for generating light flashes close to 1 ms.

[Echocardiographic evaluation of the significance of shunt in secondary communications and in partial abnormal pulmonary venous returns]. / Evaluation par échocardiographie de l'importance du shunt dans les communications inter-auriculaires de type secundum et les retours veineux pulmonaires anormaux partiels

Although echocardiography has been useful in diagnosing significant left-to-right shunts at the atrial level, few studies using this technique to quantitate shunt size have been performed. Echocardiograms and hemodynamic data from 28 patients, ages 15 to 58 (mean : 30 years) were reviewed. Twenty patients had isolated atrial septal defects (ASD), 6 patients has associated partial pulmonary venous returns (PPVR) and 2 patients had isolated PPVR. Echocardiograms in the supine position were performed within 24 hours preceding cardiac catheterization. The presence or absence of paradoxical septal motion was noted and right ventricular diameter index (RVDE : right ventricular diameter/body surface area) was calculated. Hemodynamic parameters studied included pulmonary to systemic flow ratio (Qp/Qs) determined by oxymetry, right ventricular pressure (RVP) and pulmonary resistance (PR). One patient with a Qp/Qs of 1.3 had normal septal motion. Type A paradoxical septal motion was noted in 22 cases, type B in 5 cases. For these 27 patients, the average RVDI was 2.42 (range 1.45 to 3.7), Qp/Qs ranged from 1.5 to 5 (mean : 2.45), RVP from 23 to 71 mmHg (mean : 39) and PR from 0.6 to 4 units (mean : 1.79). A very strons correlation between RVDI and Qp/Qs was observed from equation Qp/Qs : 1.19 RVDI-0.43 with a standard error of 0.4. This relationship was not altered by either RVP or PR values, which also had no apparent correlation with RVDI. This study indicates that echocardiographic measurement of RVDI is a reliable and non-invasive method of evaluating the size of left to right shunts at the atrial level.