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.

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.

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.

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.

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.

[Psychometric properties of the French version of the Modified Mini-Mental State (3MS) in elderly patients evaluated in geriatric psychiatry]

OBJECTIVE

This research evaluates the psychometric properties of the French version of the Modified Mini-Mental State (3MS), an instrument for the screening of dementia, in a sample of patients seen in geriatric psychiatry.

METHODS

Subjects (N = 94, 63 to 93 years of age) were outpatients of a service in geriatric psychiatry. In addition to the 3MS, a battery of tests evaluating the cognitive functioning and depressive symptomatology was administered.

RESULTS

Test-retest reliability coefficient was 0.87 for a subsample of 35 subjects. An exploratory factor analysis revealed 4 factors accounting for 63.2% of the variance. Cut-off scores of 79 to 80 (with years of education > or = 8) and 71 to 72 (with years of education < or = 7) presented the best combination sensitivity/specificity, respectively 0.80 and 0.96.

CONCLUSIONS

This study documents the psychometric properties of the French version of the 3MS for use in patients seen in geriatric psychiatry, in suggesting cut-off scores which take into account the level of education. This study underlines the influence of sociodemographic variables on test performance.

Identification of variability of ribosomal DNA spacer from Pseudomonas soil isolates

The polymerase chain reaction was used to amplify the spacer region located between the 16S and 23S ribosomal RNA genes of strains of Pseudomonas fluorescens and Pseudomonas putida isolated from peat bog, canola field, or arctic plants. Some of spacer region of four of the P. fluorescens strains examined, strains 64-3, 63-28, QP5, and R17-FP2, was about 515 base pairs (bp) in length, and contained the genes for tRNA(Ile) and tRNA(Ala). The DNA sequences of two strains from canola, 64-3 and 63-28, differed at only two positions. The sequences of the peat bog strains QP5 and R17-FP2 were identical. However, differences were noted between the DNA sequence common to the pair of strains 64-3 and 63-28 and the corresponding common sequence for strains QP5 and R17-FP2. These differences were mainly concentrated in two DNA segments of 10 and 19 bp, respectively. A probe for the 19-bp variable segment that occurs in the ribosomal spacer of strains QP5 and R17-FP2 recognized total DNA from these two strains, but not DNA from other bacteria of different origins. These results suggest the existence of a limited degree of variability within the 16S-23S ribosomal DNA spacer region, and that this variability may be useful to the recognition of particular Pseudomonas strains from environmental samples.

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.

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.

Inhibition de champignons phytopathogènes par des bactéries isolées du sol et de la rhizosphère de légumineuses

The antifungal activity of 644 bacterial isolates obtained from soil and from the rhizosphere of some leguminous plants was studied with one hyperparasite and six pathogenic fungi frequently associated with leguminous or gramineous plants. More than half (51.2%) of the bacterial isolates inhibited at least one fungus and 1.7% had an inhibitory effect on all the fungi tested. Stemphylium sarcinaeforme was the most sensitive fungus (inhibited by 27.0% of the bacteria tested), while Fusarium solani and Gliocladium roseum were the most resistant (inhibited by only 7.6 and 7.8% of the isolates, respectively). Verticillium albo-atrum and Fusarium oxysporum f. sp. medicaginis, important pathogens of alfalfa, were inhibited by 17.7 and 14.7% of the bacteria, respectively. Among the 166 bacteria showing the most important inhibitory effect on fungi, 7.2% inhibited strain A2 of Rhizobium meliloti and 21.1%, strain S14. In general, we obtained higher percentages of bacteria inhibiting fungi and Rhizobium meliloti from rhizospheric than from nonrhizospheric soil. When incorporated in the growth medium, some Pseudomonas spp. and Bacillus spp. reduced the growth surface of the tested fungi by more than 90%. Some bacteria reduced the mycelium density rather than the growth surface.

Tip potential of open-tip glass microelectrodes: theoretical and experimental studies

A mathematical analysis of the tip potential based on the main physicochemical phenomena occurring at the tip of a glass microelectrode is presented. The factors considered in the theoretical analysis are the diffusion of ions through the open tip, the conduction in the bulk solutions, the longitudinal conduction in the double layers at the glass-electrolyte interfaces, and to some extent, in a hydrated glass layer. A graphical analysis of the mathematical expressions as a function of the resistivity of test solutions is done and the distribution of the source potentials giving rise to the tip potential is studied. The experimental results presented in the paper confirm the validity of the proposed theoretical model. Comments for an improved use of glass microelectrodes in electrophysiological experiments are given throughout the paper.

[Left auricular myxoma. Apropos of 9 cases. Study of echocardiographic and morphologic aspects. Familial inquiry]

A study was made of 9 cases of left atrial myxoma with emphasis on the echocardiographic, haemodynamic and anatomical aspects and on the main clinical features. An epidemiological enquiry was made regarding the possibility of recurrences or familial cases. It was negative, suggesting that such cases are rare. The echocardiographic signs of left atrial myxoma are inconstant. The mitral diastolic EF slope is variable, the delay in appearance of the tumour echo behind the mitral valve in diastole is not constant, and the atrial "a" wave may be preserved. The echocardiographic features are a function of the size and shape of the myxoma, as well as the length and site of implantation of its pedicle.

[Diagnosis of left auricular myxomas by echocardiography. 2 cases]

The echocardiograms of two patients with a myxoma of the left atrium are presented. In each case there was an abnormal echo mass visible in diastole behind the greater mitral cusp. In addition, in one case, the mass was seen in the left atrium in tricuspid and aortic projection. The diagnosis was not suspected clinically and it was the ultrasound examination, carried out on a routine basis, which led to its discovery. This noninvasive technique is thus a valuable study in the demonstration of myxomas of the left atrium.

[Echocardiographic evaluation of the significance of shunt in secondary communications and in partial abnormal pulmonary venous returns]

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.

[Study of tetralogy of Fallot by echocardiography]

Twelve patients with a Fallot's tetralogy proved by a haemodynamic and angiographic examination were studied by echography, a non invasive technique. The diameters of the right and left ventricles, of the left atrium and of the aorta were measured. The movements of the interventricular septum and the position of the aorta in relation to it were analysed. Moreover, by scanning of the left ventricle an opening was looked for in the septum. The ventricular septal defect together with a dilatation of the right ventricle and a more or less intense dilatation of the root of the aorta were found in all cases. In 10 cases, an aorta overriding the septum was observed, and this was the more obvious the older the child. In the two post-operative cases studied, the septum was found to be in line with the aorta. There are therefore echocardiographic criteria making it possible to diagnose Fallot's tetralogy. These criteria are the more obvious the older the child.