Individual and joint toxicity of the herbicide S-metolachlor and a metabolite, deethylatrazine on aquatic crustaceans: Difference between ecological groups.

We studied the individual and joint acute toxicity of S-metolachlor (SMOC) and deethylatrazine (DEA - a metabolite of atrazine) on different non-target freshwater crustaceans. We used animals from different ecological groups: two amphipods from surface running water (Gammarus pulex and Gammarus cf. orinos), an isopod from surface stagnant water (Asellus aquaticus) and an amphipod living in groundwater (Niphargus rhenorhodanensis). Organisms were exposed to different levels of SMOC and DEA, alone or in binary mixture. Temperature effect on SMOC toxicity was assessed by exposing G. pulex and N. rhenorhodanensis to SMOC at 11 °C and 15 °C. Studying mortality as the biological endpoint, N. rhenorhodanensis was more resistant than surface water species towards SMOC and DEA. Among surface water species, G. pulex was the most sensitive while Gammarus cf. orinos and A. aquaticus showed similar responses to both compounds. Temperature increase did not change SMOC toxicity but modify the shape and steepness of the dose-response curve. We used a Model Deviation Ratio (MDR) approach to evaluate the predictability of Concentration Addition (CA) and Independent Action (IA) models to mixture toxicity. Results indicated either an additive or an antagonistic or a synergistic interaction depending on the concentrations combination and the test species. Our finding conclusively show the suitability of CA and IA in predicting mixture toxicities but results should be interpreted with caution according to ecological group of exposed species in risk assessment procedures.

Persistent and emerging micro-organic contaminants in Chalk groundwater of England and France.

The Chalk aquifer of Northern Europe is an internationally important source of drinking water and sustains baseflow for surface water ecosystems. The areal distribution of microorganic (MO) contaminants, particularly non-regulated emerging MOs, in this aquifer is poorly understood. This study presents results from a reconnaissance survey of MOs in Chalk groundwater, including pharmaceuticals, personal care products and pesticides and their transformation products, conducted across the major Chalk aquifers of England and France. Data from a total of 345 sites collected during 2011 were included in this study to provide a representative baseline assessment of MO occurrence in groundwater. A suite of 42 MOs were analysed for at each site including industrial compounds (n=16), pesticides (n=14) and pharmaceuticals, personal care and lifestyle products (n=12). Occurrence data is evaluated in relation to land use, aquifer exposure, well depth and depth to groundwater to provide an understanding of vulnerable groundwater settings.

Emerging organic contaminants in groundwater: A review of sources, fate and occurrence.

Emerging organic contaminants (EOCs) detected in groundwater may have adverse effects on human health and aquatic ecosystems. This paper reviews the existing occurrence data in groundwater for a range of EOCs including pharmaceutical, personal care, 'life-style' and selected industrial compounds. The main sources and pathways for organic EOCs in groundwater are reviewed, with occurrence data for EOCs in groundwater included from both targeted studies and broad reconnaissance surveys. Nanogram-microgram per litre concentrations are present in groundwater for a large range of EOCs as well as metabolites and transformation products and under certain conditions may pose a threat to freshwater bodies for decades due to relatively long groundwater residence times. In the coming decades, more of these EOCs are likely to have drinking water standards, environmental quality standards and/or groundwater threshold values defined, and therefore a better understanding of the spatial and temporal variation remains a priority.

The mechanism of CO2- radical formation in biological and synthetic apatites.

Biological apatites (tooth enamel, bone) and their synthetic analogues were exposed to gamma rays, UV light, or thermal treatment and studied by electron paramagnetic resonance (EPR). The thermal generation of CO2- radicals in synthetic apatite was observed for the first time. It was shown that the experimental EPR spectra of all of the above-mentioned materials are caused by the contribution of two types of CO2- radicals: axial and orthorhombic. The ratio of their concentrations depends on the characteristic energy of the external influence (i.e., the energy of quantum for radiation or kT for thermal treatment) and also on the quality of the initial material (defectiveness). Based on the analysis of EPR spectra recorded immediately after gamma-irradiation, the authors conclude that the main short-lived radical in bioapatites is CO3(3)- . The unified mechanism of CO2- radical formation in hydroxyapatites at different external influences is proposed; the main stages of transformation are CO3(2)- + e --> CO3(3)- --> CO2-, where the electron (e) originates from the ionization of impurities by radiation/temperature.

Hydrodynamic and geochemical constraints on pesticide concentrations in the groundwater of an agricultural catchment (Brévilles, France).

The monitoring of a spring and seven piezometers in the 3km(2) Brévilles agricultural catchment (France) over five and a half years revealed considerable spatial and temporal variability in the concentrations of atrazine and its metabolite deethylatrazine (both systematically quantified at the outlet spring): maximum 0.97 and 2.72microgL(-1), mean 0.19 and 0.59microgL(-1), respectively. Isoproturon, the pesticide applied in the greatest amount, was detected in only 10 of the 133 samples. These observations can only partly be explained by land use and intrinsic pesticide properties. Geochemical measurements and tritium dating showed the importance of the stratification of the sandy saturated zone and the buffer function of the unsaturated limestone. Principal component analysis on 39 monthly data series of atrazine, deethylatrazine, nitrate, chloride and piezometric levels revealed a temporal structuring of the data possibly reflecting the existence within the aquifer of two different reservoirs with time-variable contributions.

Separation of the contributions from gamma- and UV-radiation to the EPR spectra of tooth enamel plates.

Anisotropy of EPR spectra of tooth enamel plates irradiated with gamma-rays and UV light has been studied. UV-irradiated enamel plates exhibit a stronger anisotropy than gamma-irradiated plates. Investigation of samples cut out of different teeth and irradiated to different doses showed that the value of anisotropy is characteristic of each type of irradiation; it equals to approximately 0.35 for gamma- rays and 0.50 for UV light. It is suggested that the difference in the anisotropy values can be attributed to different relative amounts of oriented and disordered radicals produced by the two types of radiation. This can be used for separating gamma- and UV-contributions to the total EPR signal of a tooth exposed to both types of radiation.

Pesticides in the groundwater of a spring draining a sandy aquifer: temporal variability of concentrations and fluxes.

A 250 ha agricultural catchment has been characterized with respect to its hydrogeology and groundwater contamination by pesticides from October 1999 to August 2004. Five years after the ending of atrazine (At) application, used since the sixties, At and deethylatrazine (DEA) are still systematically quantified at the outlet of the watershed with concentrations from 0.07 to 0.43 microg l(-1) for At, and between 0.14 and 1.16 microg l(-1) for DEA. Isoproturon and chlortoluron are detected in only one (0.3 microg l(-1)) and two (0.7 and 2.0 microg l(-1)) of the 124 semi-monthly samples, respectively. DEA concentrations can be very different between two samples with a 15-day time step. The annual mean exported fluxes of cumulated At and DEA are stable, which indicates a long time transfer in the unsaturated or saturated zone with a progressive leaching of the stock of At and DEA probably accumulated in the soil and the vadose zone. These fluxes, between 0.90% and 2.82% of the annual mean dose of At applied before 1999, similar to those calculated in several studies at the bottom of the root zone, could be explained by low adsorption and degradation properties of At and DEA in the unsaturated and saturated zone.

The persisting analgesic effect of low-dose intravenous ketamine after spinal anaesthesia for caesarean section.

BACKGROUND AND OBJECTIVES: To compare the analgesic effects of intrathecal fentanyl and low-dose intravenous ketamine as adjuvants to intrathecal bupivacaine for Caesarean section. METHODS: Ninety elective Caesarean section patients were randomized into three groups. Spinal anaesthesia was performed with 15 mg hyperbaric bupivacaine in all groups. Ketamine (0.15 mg kg(-1)) or an equal volume of normal saline was given intravenously immediately after initiating spinal anaesthesia in the ketamine and control group, respectively. In the fentanyl group, 10 microg fentanyl was added to the intrathecal bupivacaine. Arterial pressures, heart rate values, adverse effects, the time of first request for postoperative analgesia, visual analogue pain scores, total analgesic consumptions at 24 and 48 h were recorded in all patients. RESULTS: The time to first request for analgesia was significantly longer in the ketamine (197 min) and fentanyl (165 min) groups compared to the control group (144 min). Postoperative pain scores were significantly lower in the ketamine group than in both other groups. Although the analgesic requirements during first 24 h were significantly lower in the ketamine group, there was no significant difference between the groups during the following 24 h. CONCLUSION: Intravenous low-dose ketamine combined with intrathecal bupivacaine for Caesarean section provides longer postoperative analgesia and lower postoperative analgesic consumption than bupivacaine alone suggesting a pre-emptive effect.

Determination of chloroacetanilides, triazines and phenylureas and some of their metabolites in soils by pressurised liquid extraction, GC-MS/MS, LC-MS and LC-MS/MS.

Pressurised liquid extraction (PLE) technique was used for the simultaneous extraction of phenylureas, triazines and chloroacetanilides and some of their metabolites from soils. Extractions were performed by mixing 15 g of dried soil with 30 mL of acetone under 100 atm at 50 degrees C, during 3 min and with three PLE cycles. Prior to the analysis of naturally contaminated soils, each of the five representative soil matrices used as blanks (of different depths) was spiked in triplicate with standards of each parent and degradation compound at about 10, 30 and 120 microg/kg. For each experiment, isoproturon-D6 and atrazine-D5 were used as surrogates. Analysis of phenylureas and metabolites of triazines and phenylureas was carried out by reversed phase liquid chromatography/mass spectrometry (LC-MS) and LC-MS/MS in the positive mode. Gas chromatography (GC)/ion trap mass spectrometry was used in the MS/MS mode for the parent triazines and chloroacetanilides. The average extraction recoveries were above 85%, except for didesmethyl-isoproturon, and quantification limits were between 0.5 and 5 microg/kg. The optimised multi-residue method was applied to soils and solids below the root zone, sampled from agricultural plots of a small French hydrogeological basin.

Determination of oxanilic and sulfonic acid metabolites of acetochlor in soils by liquid chromatography-electrospray ionisation mass spectrometry.

An analytical method is presented that describes the extraction and quantification of oxanilic and sulfonic acid metabolites of the herbicide acetochlor in soil samples. Experiments were performed on 50 g of soil using a solvent extraction technique with an acetonitrile-water (60:40) mixture in an acidic medium. Analysis was carried out by reversed-phase liquid chromatography and detection by electrospray ionisation mass spectrometry in single ion monitoring and negative modes. Four different soil matrices were spiked in triplicate with standards of each degradation compound at three concentration levels between 2 and 80 microg/kg. The average recoveries range from 90 to 120% for both the metabolites, with relative standard deviations lower than 15%. The limits of quantification are about 1 and 2 microg/kg for the ethanesulfonic acid and the oxanilic acid metabolites, respectively. The method has been applied to soils and solids recovered from the deeper unsaturated zone of a small French catchment closely monitored as part of the European project "Pesticides in European Groundwaters: detailed study of Aquifers and Simulation of possible Evolution scenarios (PEGASE)".

13C hyperfine interactions of CO2- in irradiated tooth enamel as studied by EPR.

The EPR spectrum of tooth enamel caused by 13C hyperfine interactions of the CO2- radical were studied on gamma-irradiated powdered samples annealed for 40 min at different temperatures up to 250 degrees C. The lineshape and hyperfine splitting of the spectra were found to depend on the annealing temperature. Experimental spectra were compared with calculated ones assuming that EPR spectra are formed by two CO2- species--axial (rotating) and orthorhombic (braked) radicals. We assumed that the axial CO2- radicals are centers located in perfect areas of the hydroxyapatite crystals of tooth enamel whereas the orthorhombic CO2- radicals are rotating centers which are braked by defects. The thermal treatment of enamel samples leads to defective annealing and transformation of the orthorhombic centers into axial ones. This results in an increasing axial CO2- radical contribution to the EPR spectrum with increase of annealing temperature.

A different strategy in the surgical treatment of capsular contracture: leave capsule intact.

The authors present their experience with the surgical treatment of capsular contracture to achieve better results in a safe, predictable, and practical way, and discuss the possible treatment modalities. They simply advise leaving the capsule intact, even if it is calcified, and create another pocket, rarely in the front or, more typically, at the back of the capsule. If the breast tissue is also ptotic, a mastopexy procedure may be added to the procedure, in addition to augmentation, with a rather small prosthesis placed in the new pocket or, occasionally, in the old one. External, forceable massage is not advisable to treat the capsule. Open capsulotomy and/or partial capsulectomy can be applied to release the capsule. However, it is not advisable since recurrence is usually inevitable. The purpose of this paper is to present a series of surgical procedures to avoid the problems created by the capsule and present different cases with good results.

Unsatisfactory results of periareolar mastopexy with or without augmentation and reduction mammoplasty: enlarged areola with flattened nipple.

A method of repair is described for correction of abnormally enlarged nipple-areola complex following both periareolar mastopexy and pregnancy. Although during periolar mastopexy or reduction mammoplasty regular subcuticular dermal sutures may control the enlargement of nipple-areola complexes initially, the periareolar scar becomes hypertrophic and areolar spreading occurs to some extent. Periareolar mastopexy techniques are indeed advisable only for minimal hypertrophies or ptosis of the breast, especially for areolar asymmetry, if an acceptable, normal-size areola is expected. The authors believe that in periolar mastopexy or reduction mammoplasty cases resulting in enlarged nipple-areola complexes, the size of the areola can also be corrected by reduction mammoplasty or mastopexy using vertical bipedicle techniques. Although surgery results in an inverted T incision, the shape of the breast is more acceptable and the size of the areola does not enlarge with time.

Rescue of preimplantatory egg development and embryo implantation in prolactin receptor-deficient mice after progesterone administration.

PRL, a hormone secreted essentially by the pituitary and other extrapituitary sources such as decidua, has been attributed regulatory roles in reproduction and cell growth in mammals. These effects are mediated by a membrane PRL receptor belonging to the cytokine receptor superfamily. Null mutation of the PRL receptor gene leads to female sterility due to a severely compromised preimplantation development and a complete failure of the implantation of the few embryos reaching the blastocyst stage, strongly implicating PRL in the maternal control of implantation. We measured the hormonal status of -/- mice, which confirmed that the corpus luteum is unable to produce progesterone. Progesterone administration to -/- mice completely rescued the development of preimplantatory eggs and embryo implantation. Pregnancy could be maintained to 19.5 days postcoitum, with about 22% of resulting embryos reaching adulthood. Although progesterone and perhaps PRL appear to facilitate mouse preembryo development throughout the preimplantation stages, other factors as well as a possible direct effect of PRL on the uterus are probably necessary to fully maintain pregnancy. Finally, reduced ductal side-branching in the mammary gland can be rescued by progesterone treatment, but females exhibit reduced alveolar formation. Our model establishes the PRL receptor as a key regulator of reproduction and provides novel insights into the function of lactogenic hormones and their receptor.

Interference footprinting analysis of telomerase elongation complexes.

Telomerase is a reverse transcriptase that adds single-stranded telomeric repeats to the ends of linear eukaryotic chromosomes. It consists of an RNA molecule including a template sequence, a protein subunit containing reverse transcriptase motifs, and auxiliary proteins. We have carried out an interference footprinting analysis of the Tetrahymena telomerase elongation complexes. In this study, single-stranded oligonucleotide primers containing telomeric sequences were modified with base-specific chemical reagents and extended with the telomerase by a single (32)P-labeled dGMP or dTMP. Base modifications that interfered with the primer extension reactions were mapped by footprinting. Major functional interactions were detected between the telomerase and the six or seven 3'-terminal residues of the primers. These interactions occurred not only with the RNA template region, but also with another region in the enzyme ribonucleoprotein complex designated the telomerase DNA interacting surface (TDIS). This was indicated by footprints generated with dimethyl sulfate (that did not affect Watson-Crick hydrogen bonding) and by footprinting assays performed with mutant primers. In primers aligned at a distance of 2 nucleotides along the RNA template region, the footprints of the six or seven 3'-terminal residues were shifted by 2 nucleotides. This shift indicated that during the elongation reaction, TDIS moved in concert with the 3' ends of the primers relative to the template region. Weak interactions occurred between the telomerase and residues located upstream of the seventh nucleotide. These interactions were stronger in primers that were impaired in the ability to align with the template.

From the molecular biology of prolactin and its receptor to the lessons learned from knockout mice models.

Prolactin (PRL), a polypeptide hormone secreted mainly by the pituitary and, to a lesser extent, by peripheral tissues, affects more physiological processes than all other pituitary hormones combined since it is involved in > 300 separate functions in vertebrates. Its main actions are related to lactation and reproduction. The initial step of PRL action is the binding to a specific membrane receptor, the PRLR, which belongs to the class 1 cytokine receptor superfamily. PRL-binding sites have been identified in a number of tissues and cell types in adult animals. Signal transduction by this receptor is mediated, at least in part, by two families of signaling molecules: Janus tyrosine kinases and signal transducers and activators of transcription (STATs). Disruption of the PRLR gene has provided a new mouse model with which to identify actions directly associated with PRL or any other PRLR ligands, such as placental lactogens. To date, several different phenotypes have been analyzed and are briefly described in this review. Coupled with the SAGE technique, this PRLR knockout model is being used to qualitatively and quantitatively evaluate the expression pattern of hepatic genes in two physiological situations: transcriptomes corresponding to livers from both wild type and PRLR KO mice are being compared, and following statistical analyses, candidate genes presenting a differential profile will be further characterized. Such a new approach will undoubtedly open future avenues of research for PRL targets. To date, no pathology linked to any mutation in the genes encoding PRL or its receptor have been identified. The development of genetic models provides new opportunities to understand how PRL can participate to the development of pathologies throughout life, as for example the initiation and progression of breast cancer.

DNA molecules can drive the assembly of other DNA molecules into specific four-stranded structures.

Single-stranded DNA molecules containing clustered G-repeats can be assembled into various four-stranded structures linked by G-quartets. Here, we report that such molecules can also drive the assembly of other DNA molecules containing G-repeats into specific four-stranded structures. In these assays, the oligonucleotides 5'-CAGGCTGAGCAGGTACGGGGGAGCTGGGGTAGATTGGAATGTAG-3' (oligo D) and 5'-CGGGGGAGCTGGGGT-3' (oligo B), consisting of sequences found in immunoglobulin switch regions, were annealed in a buffer containing K+ and the annealing products were analyzed by polyacrylamide gel electrophoresis. This analysis revealed that whereas annealing of each oligo alone produced four-stranded structures designated D2 and B2, annealing of mixtures containing both oligos produced additional complexes designated D2* and B2*. D2* and B2* were found to contain only D molecules and only B molecules, respectively. The yield of D2* increased and the yield of B2* decreased, as the concentration ratio oligo B/oligo D was increased. These results indicated that B can drive the assembly of D into D2* and D can drive the assembly of B into B2*. Further studies revealed that while the assembly of D2 followed a second order kinetics, the B-driven assembly of D2* followed a first order kinetics. Dimethyl sulfate footprinting indicated that both D2 and D2* are four-stranded structures containing two parallel and two antiparallel chains. In addition, annealing of D mixed with various B mutants showed that only mutants containing two G-clusters can drive the assembly of D2*. Based on these data, we propose that in the process of D2* assembly, a four-stranded intermediate containing B and D is formed and then dissociates into D2* and B in a rate-limiting first order reaction. Driver mechanisms of this type may cause formation of specific four-stranded structures at G-rich chromosomal sites, thereby regulating processes such as recombination and telomere synthesis.

Combined chemical peeling and dermabrasion for deep acne and posttraumatic scars as well as aging face.

The combination of chemical peeling and dermabrasion for the improvement of facial wrinkles, acne, posttraumatic scars, and abnormal pigmentation was first described by Dupont in 1972 and Horton in 1984. We have been using the combined technique since 1972, and we have obtained more satisfying results than by using these techniques independently. The purpose of this paper is to summarize the results obtained using the combined technique of chemical peeling and dermabrasion and to emphasize a simple method of postoperative care that can be applied after any physical or chemical rejuvenation technique. Whereas the combined technique takes advantage of depth-controlled surgery, less bleeding, less postoperative pain, less risk of local and systemic complications, and longer lasting results, the covering of the wound with one layer of fine mesh gauze is another advantage that provides easy postoperative care.