Biomedical subjects

G Mercier

Publications and source records attributed to G Mercier.

At least 19 recordsLinked to original sources

PubMed2006

[In vitro fertilization and smoking: use of urinary cotinine and expired air carbon monoxide measurements].

OBJECTIVE: To study the correlation between expired air carbon (EACO) and urinary cotinine, and to determine the impact of tobacco smoking on in vitro fertilization (IVF) results. PATIENTS AND METHODS: We studied prospectively 221 patients in our ART center from October 2002 to October 2004: 51 active smokers, 85 passive smokers, and 85 non-smokers. Patients were classified into active, passive smokers, or non-smokers, based on a questionnaire. We measured urinary cotinine and EACO on the embryo transfer day and we recorded the IVF parameters. RESULTS: Two hundred and twenty-one patients were included. We observed a 17.2% reduction of estradiolemy (P=0.05), a 1.5% reduction of pregnancies (NS), a 7.8% reduction of infants born alive (NS), a 28.5% reduction of twin pregnancies (P=0.06), as well as a 10% increase of miscarriages (NS) in the active smokers in comparison with non-smokers (the same trends were observed between active and passive smokers). EACO and urinary cotinine were well correlated. There was a negative correlation between estradiolemy and urinary cotinine (R=-0.15, P=0.02). DISCUSSION AND CONCLUSION: Tobacco smoking intensity may be dilatory on IVF results. There is a high correlation between EACO and urinary cotinine. Other larger studies would probably obtain results more statistically significant.

Adolescent↗

PubMed2006

[General practitioners' and intensivists' relationships: intensivists' point of view from eight French southern regional areas].

OBJECTIVES: Assessment of relationship between general practitioners and intensivists. STUDY DESIGN: Intensivists were questioned by phone from June 14th to September 28th 2004. METHODS: 245 out of 264 intensivists from 8 French Southern regional areas were questioned concerning their relationship with critically ill patients' general practitioner. RESULTS: Patients were mainly admitted into Intensive care Unit (ICU) from the Emergency Department (55%). An information letter from the general practitioner was reported for 20% of admitted patients but 50% of these letters was assumed as not informative. The informations concerning the patient's medical history, therapies, and disease leading to admission and the patient's status were assessed with 6.5, 7.0, 6.0 and 2.0, respectively (maximal note=10). The intensivists contacted the general practitioner for 30% of admitted patients. During the stay in ICU, 33% general practitioners were reported to request informations by phone or visit in ICU. When the stay in ICU was>10 days, the general practitioner was nearly never regularly informed about patient's status. When the patient was discharged from the ICU, 80% of intensivists used an exhaustive typed report to inform the general practitioner. The overall relationship between the general practitioner and the intensivist was assessed as 5.5/10. Insufficient information in the general practitioner's letter at admission, the lack of request for information during the stay in ICU, the lack of contact with the general practitioner by the intensivist and an intensivist's age between 46 and 55 were associated with a relationship assessment<4/10).

Adult↗

PubMed2006

[PAH removal from black sludge from aluminium industry by flotation using non-ionic surfactants].

The valorization of black sludge is an environmental problem of the aluminium industry because of Polycyclic Aromatic Hydrocarbon (PAH), fluoride and alumina contents. A soil washing operated in a cell flotation with non-ionic surfactants (Brij 35, Igepal CA-720, Triton X-100, Tween 80) at different concentrations has been tested in order to remove the PAH (benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(j)fluoranthene, benzo(k)fluoranthene, fluoranthene) detected in black sludge. The Tween 80 at 0.5% gave the best results with PAH removal rates between 35 and 50%. These percentages remain low due to the presence in large quantity of fine solid particles (45%) in the PAH concentrate produced by the flotation process. The substitution of the cell flotation by a column flotation allowed the reduction of this problem. Thus, the PAH removal rates reached 60%. This removal yield has been obtained with the lowest wash water flow-rate (150 ml min(-1)) and pulp total solids (10% p p(-1)) tested.

Aluminum↗

PubMed2006

Transcriptional disruptions in Down syndrome: a case study in the Ts1Cje mouse cerebellum during post-natal development.

To understand the aetiology and the phenotypic severity of Down syndrome, we searched for transcriptional signatures in a substructure of the brain (cerebellum) during post-natal development in a segmental trisomy 16 model, the Ts1Cje mouse. The goal of this study was to investigate the effects of trisomy on changes in gene expression across development time. The primary gene-dosage effect on triplicated genes (approximately 1.5) was observed at birth [post-natal day 0 (P0)], at P15 and P30. About 5% of the non-triplicated genes were significantly differentially expressed between trisomic and control cerebellum, while 25% of the transcriptome was modified during post-natal development of the cerebellum. Indeed, only 165, 171 and 115 genes were dysregulated in trisomic cerebellum at P0, P15 and P30, respectively. Surprisingly, there were only three genes dysregulated in development and in trisomic animals in a similar or opposite direction. These three genes (Dscr1, Son and Hmg14) were, quite unexpectedly, triplicated in the Ts1Cje model and should be candidate genes for understanding the aetiology of the phenotype observed in the cerebellum.

Animals↗

PubMed2005

A haploid-specific transcriptional response to irradiation in Saccharomyces cerevisiae.

Eukaryotic cells respond to DNA damage by arresting the cell cycle and modulating gene expression to ensure efficient DNA repair. We used global transcriptome analysis to investigate the role of ploidy and mating-type in inducing the response to damage in various Saccharomyces cerevisiae strains. We observed a response to DNA damage specific to haploid strains that seemed to be controlled by chromatin regulatory proteins. Consistent with these microarray data, we found that mating-type factors controlled the chromatin-dependent silencing of a reporter gene. Both these analyses demonstrate the existence of an irradiation-specific response in strains (haploid or diploid) with only one mating-type factor. This response depends on the activities of Hdf1 and Sir2. Overall, our results suggest the existence of a new regulation pathway dependent on mating-type factors, chromatin structure remodeling, Sir2 and Hdf1 and independent of Mec1 kinase.

Antigens, Nuclear↗

PubMed2005

[Study of the metal precipitation from decontamination leachates of municipal wastes fly ash incinerators].

This research work focuses on the development of a new process for the decontamination of municipal wastes incinerators fly ashes. The objective of this study was to evaluate different total and selective precipitation methods for metals removal from ash decontamination leachates. The tested options include 1) use of hydrated lime and caustic soda for selective (pH 5.0) and total (pH 8.5) metal precipitation; 2) addition of different chemicals (H3PO4, Na2S and FeCl3) in a pH range from 6.0 to 9.0. Fly ash decontamination assays using alkaline and acid washing steps were initially performed using optimal conditions previously established. Treated fly ashes respected the standards based on the TCLP leaching test for all studied metals and SPLP. Total metal precipitation tests carried out at pH 8.5 achieve removal yields for all metals > or = 90% using hydrated lime and > or = 83% using caustic soda. Selective precipitation tests alone at pH 5.0 show removal yields > or = 97% for Cr and between 75 and 87% for Al and Pb. Moreover, assays carried out using a stoechiometric addition of Na2S have allowed the separation of Cd (> or = 99%) and Zn (> or = 71%) as metal sulphides (CdS and ZnS). From an economical point of view, the most interesting option seems to be the leachates neutralization at pH 7.0 using Ca(OH)2 combined with the reuse of the treated leachates in the fly ash leaching steps. Metal precipitation cost at pH 7.0 has been estimated to be 22.7 CAN dollars tct-1 using Ca(OH)2, and 26.7 CAN dollars tct-1 using NaOH.

Carbon↗

PubMed2004

Biological detection of low radiation doses by combining results of two microarray analysis methods.

The accurate determination of the biological effects of low doses of pollutants is a major public health challenge. DNA microarrays are a powerful tool for investigating small intracellular changes. However, the inherent low reliability of this technique, the small number of replicates and the lack of suitable statistical methods for the analysis of such a large number of attributes (genes) impair accurate data interpretation. To overcome this problem, we combined results of two independent analysis methods (ANOVA and RELIEF). We applied this analysis protocol to compare gene expression patterns in Saccharomyces cerevisiae growing in the absence and continuous presence of varying low doses of radiation. Global distribution analysis highlights the importance of mitochondrial membrane functions in the response. We demonstrate that microarrays detect cellular changes induced by irradiation at doses that are 1000-fold lower than the minimal dose associated with mutagenic effects.

Analysis of Variance↗

PubMed2004

Removal of metals in leachate from sewage sludge using electrochemical technology.

Heavy metals in acidic leachates from sewage sludge are usually removed by chemical precipitation, which often requires high concentration of chemicals and induces high metallic sludge production. Electrochemical technique has been explored as an alternative method in a laboratory pilot scale reactor for heavy metals (Cu and Zn) removal from sludge leachate. Three electrolytic cell arrangements using different electrodes materials were tested: mild steel or aluminium bipolar electrode (EC cell), Graphite/stainless steel monopolar electrodes (ER cell) and iron-monopolar electrodes (EC-ER cell). Results showed that the best performances of metal removal were obtained with EC and EC-ER cells using mild steel electrodes operated respectively at current intensities of 0.8 and 2.0 A through 30 and 60 min of treatment. The yields of Cu and Zn removal from leachate varied respectively from 92.4 to 98.9% and from 69.8 to 76.6%. The amounts of 55 and 44 kg tds(-1) of metallic sludge were respectively produced using EC and EC-ER cells. EC and EC-ER systems involved respectively a total cost of 21.2 and 13.1 CAN dollars per ton of dry sludge treated including only energy consumption and metallic sludge disposal. The treatment using EC-ER system was found to be effective and more economical than the traditional metal precipitation using either Ca(OH)2 and/or NaOH.

Conservation of Energy Resources↗

PubMed2003

Brief communication: Y-chromosome haplotypes in Egypt.

We analyzed Y-chromosome haplotypes in the Nile River Valley in Egypt in 274 unrelated males, using the p49a,f TaqI polymorphism. These individuals were born in three regions along the river: in Alexandria (the Delta and Lower Egypt), in Upper Egypt, and in Lower Nubia. Fifteen different p49a,f TaqI haplotypes are present in Egypt, the three most common being haplotype V (39.4%), haplotype XI (18.9%), and haplotype IV (13.9%). Haplotype V is a characteristic Arab haplotype, with a northern geographic distribution in Egypt in the Nile River Valley. Haplotype IV, characteristic of sub-Saharan populations, shows a southern geographic distribution in Egypt.

Adult↗

PubMed2003

[Bioleaching kinetic of a pyrite mining residue using organic wastes as culture media for Acidithiobacillus ferrooxidans].

In this study, the results of the leaching of metal sulphide concentrate using organic wastes as culture media for Acidithiobacillus ferrooxidans are summarized. These results indicate that the liquid fraction of municipal sewage sludge, paper mill sludge and pig manure, containing 10% (w v(-1)) pulp density of a pyritic mine waste concentrate can support the growth of the leaching bacteria and allow metal solubilization. The inhibition by dissolved organic carbon (DOC) appeared when the concentration in pig manure liquid fraction and sewage sludge filtrate is higher than 180 mg l(-1) and 500 mg l(-1), respectively. However, increase in organic concentration up to 650 mg l(-1) using paper mill sludge supernatant had no inhibitory effect on the bacterial growth. An important decrease of the DOC has been measured during all bioleaching tests. The organic matter was probably consumed by heterotrophic microorganisms activity. The growth rate of the iron-oxidizing bacteria varied from 0.05 to 0.07 h(-1). The dissolution of pyrite (FeS2) in organic waste media led to a yield of Fe solubilization of about 35%. Copper and zinc were also solubilized during the bioleaching tests. The yields of Cu and Zn solubilization ranged from 12 to 24%.

Acidithiobacillus↗

PubMed2003

Pregnancies after ICSI using sperm with abnormal head-tail junction from two brothers: case report.

We report ICSI pregnancies in two couples with a history of long standing primary infertility in which the sperm of the male partner were either acephalic or had abnormal head-midpiece attachments. The two couples, in which the men are brothers, underwent ICSI. Sperm were analysed by transmission electron microscopy and immunocytochemistry with an anti-MPM2 monoclonal antibody. The first couple underwent two ICSI cycles, each consisting of the injection of two mature oocytes and the transfer of two embryos. A successful pregnancy occurred after the second transfer and led to the birth to a healthy girl. The second couple underwent three ICSI cycles, each consisting of the injection of 18 oocytes and the transfer of two embryos; the last of these led to a triple ongoing pregnancy which included two identical twins. Caesarean section led to the birth of three fetal-growth restricted children. This case report demonstrates that ongoing pregnancies can be achieved in cases of abnormal development of the head-neck attachment. The genetic origin of this syndrome is generally accepted, but the phenotypic heterogeneity observed by light and electron microscopy among published cases suggests that there are a variety of genetic causes of this syndrome.

Adult↗

PubMed2002

A decontamination process to remove metals and stabilise Montreal sewage sludge.

The Montreal Urban Community (MUC) treatment plant produces approximately 270 tons of dry sludge daily (tds/day) during physicochemical wastewater treatment. The sludges are burned and contribute to the greenhouse effect by producing atmospheric CO2. Moreover, the sludge emanates a nauseating odour during its thermal stabilisation and retains unpleasant odours for the part (25%) that is dried and granulated. To solve this particular problem, the treatment plant authorities are currently evaluating an acidic chemical leaching (sulfuric or hydrochloric acid) process at a pH between 2 and 3, using an oxidizing agent such as ferric chloride or hydrogen peroxide (METIX-AC technology, patent pending; [20]). They could integrate it to a 70 tds/day granulated sludge production process. Verification of the application of METIX-AC technology was carried out in a pilot plant set up near the sludge production plant of the MUC. The tests showed that METIX-AC technology can be advantageously integrated to the process used at the MUC. The residual copper (274 +/- 58 mg/kg) and cadmium (5.6 +/- 2.9 mg/kg) concentrations in the treated sludge meet legislation standards. The results have also shown that odours have been significantly eliminated for the dewatered, decontaminated, and stabilized biosolids (> 97%) compared to the non-decontaminated biosolids. A high rate of odour elimination also was obtained for the liquid leached biosolids (> 93%), compared to the untreated liquid biosolids. The fertilising value (N and P) is well preserved by the METIX-AC process. Dissolved organic carbon measurements have showed that little organic matter is brought in solution during the treatment. In fact, the average concentration of dissolved organic carbon measured in the treated liquid phase is 966 +/- 352 mg/l, whereas it is 1190 +/- 325 mg/l in untreated sludge. The treated sludge was first conditioned with an organic polymer and a coagulant aid. It was successfully dewatered with various dehydration equipments (filter press, rotary press, centrifuge).

Canada↗

PubMed2002

[A new in vitro test to simulate gastric absorption of copper, lead, tin and zinc from polluted soils].

Metals in polluted soils can be ingested by young children and cause toxicity through gastro-intestinal absorption. Very few tests are used to evaluate the gastric absorption of metals from polluted soils. The Toxicity Characteristics Leaching Procedure (TCLP) of the Environmental Protection Agency of the United States is indirectly used as usually no action is taken on a polluted soil if lead is less than 5 mg l(-1) in the test. This paper presents a new In vitro simple screening test to detect soils polluted by metals which can cause gastric absorption. The gastric juice simulation test (GJST) is based on the chemistry of the stomach. The TCLP and the GJST has been applied to six different size fractions of 5 soils. Lead carbonate was the main form of lead pollution. Lead oxide, lead silicate, lead phosphate and PbaSnbOc(CO3)d, PbaTibOc(CO3)d and PbaCrbOc were also present. Copper is mainly found as elemental copper partly carbonated while zinc is as zinc oxide or carbonate. Tin is usually associated with iron alloy or oxide or in PbaSnbOc(CO3)d. The percentage of the surface occupied by a polluting phase is higher in small particles. The proportion of particles for which pollution is located near the surface of the particle is more important for small particles. The GJST leaches more copper, lead and zinc than the TCLP, particularly on small size fractions. Inorganic tin is not solubilised by the TCLP or the GJST. The percentage of metal leached from small particles is very important with the GJST, but not with the TCLP. The pH 5 of the TCLP is too high to solubilise much metals and is not a good test to evaluate polluted soils if gastric absorption is to be considered. For two soils out of five, the TCLP didn't detect problematic soils as detected with the Integrated Exposure Uptake Biokinetic model of the USEPA. The GJST detected all the problematic soils and is better to evaluate the chemical solubility of metals in the gastric environment. The GJST better represents the stomach environment (Cl-, pH 2, T = 37 degrees C). The GJST appears to be a good test to detect metal contaminated soils.

Absorption↗

PubMed2001

Early activation of transcription factor expression in Schwann cells by progesterone.

Progesterone (PROG) promotes the myelination of sciatic nerves during regeneration after cryolesion. But, little is known about the molecular mechanisms by which the hormone exerts its effects. This could be initiated by the regulation of transcription factor expression in Schwann cells, which produce the myelin sheaths in the peripheral nervous system. We investigated by RT-PCR whether PROG activated expression of transcription factors: Egr-1 (Krox-24) Egr-2 (Krox-20), Egr-3, c-jun, jun B, jun D, c-Fos, Fos B, Fra-1, Fra-2, CREB, ATF 4, SCIP and Sox-10 in cultured Schwann cells. PROG triggered a quick (visible as soon as 15 min), strong (6 to 18-fold) and transient (1-2 h) stimulation of Egr-1, Egr-2, Egr-3 and Fos B genes expression. Expression of other genes remained unaffected by PROG treatment. The same expression pattern was obtained in the MSC 80 line (mouse Schwann cells), but not in the NIH-3T3 and CHO lines. Estradiol and testosterone induced different patterns of transcription factor gene activation in Schwann cells. Serum stimulated all genes activated by PROG in addition c-fos, fra-1 and fra-2. The PROG effects were blocked by Actinomycin D and by RU 486. This suggests that the activation of these genes occurs at the transcriptional level via the interaction of the hormone with its cognate receptor. Thus, PROG can regulate Schwann cell functions and differentiation by transiently activating specific transcription factors.

3T3 Cells↗

PubMed2001

Transcriptional induction of repair genes during slowing of replication in irradiated Saccharomyces cerevisiae.

We investigated the inhibition of cell-cycle progression and replication and the induction of the transcriptional response in diploid budding yeast populations exposed to two different doses of gamma-rays resulting in 15 and 85% survival respectively. We studied the kinetics of the cellular response to ionizing treatment during the period required for all of the surviving cells to achieve at least one cell division. The length of these periods increased with the dose. Irradiated populations arrested as large-budded cells containing partially replicated chromosomes. The extent of the S-phase was proportional to the amount of damage and lasted 3 or 7h depending on the irradiation dose. In parallel to the division study, we carried out a kinetic analysis of the expression of 126 selected genes by use of dedicated microarrays. About 26 genes were induced by irradiation and displayed various pattern of expression. Interestingly, 10 repair genes (RAD51, RAD54, CDC8, MSH2, RFA2, RFA3, UBC5, SRS2, SPO12 and TOP1), involved in recombination and DNA synthesis, display similar regulation of expression in the two irradiated populations. Their pattern of expression were confirmed by Northern analysis. At the two doses, the expression of this group of genes closely followed the extended replication period, and their expression resumed when replication restarted. These results suggest that the damage-induced response and DNA synthesis are closely regulated during repair. The analysis of the promoter regions indicates a high occurrence of the three MCB, HAP and UASH regulatory boxes in the promoters of this group of genes. The association of the three boxes could confer an irradiation-replication specific regulation.

Blotting, Northern↗

PubMed2001

Rapid effects of triiodothyronine on immediate-early gene expression in Schwann cells.

In the peripheral nervous system, triiodothyronine (T3) plays an important role in the development and regeneration of nerve fibers and in myelin formation. However, the target genes of T3 in peripheral nerves remain to be identified. We investigated whether T3 activated genes of transcription factors in Schwann cells. Expression of egr-1 (krox-24), egr-2 (krox-20), egr-3, c-jun, junB, c-fos, fosB, fra-1, fra-2, and CREB genes was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in Schwann cells isolated from neonatal rat sciatic nerves and in the cell lines MSC-80 (mouse Schwann cells), NIH-3T3 (mouse fibroblasts), and CHO (Chinese hamster ovary cells). Some of these transcription factors have been shown to be involved in Schwann cell differentiation. T3 triggered a rapid (15-30 min), transient (1-2-h) and strong (6- to 15-fold) stimulation of Egr-1, Egr-2, Egr-3, Jun B, c-Fos, and Fos B mRNA expression in Schwann cells. In contrast, expression of c-Jun, Fra-1, Fra-2, and CREB mRNA was not affected by T3. The stimulatory effects of T3 could be abolished by adding actinomycin D. T3 triggered the same pattern of gene stimulation in the mouse Schwann cell line MSC80, but not in the NIH-3T3 and CHO cell lines. Serum activated all the genes that responded to T3 and in addition fra-1 and fra-2, but not c-jun and CREB. Immunoblotting showed that the increase in Egr-1 and c-Fos mRNA levels was accompanied by an increase in the corresponding proteins. In addition, shifts of the protein bands indicated a posttranslational modification of the two proteins. These effects of T3 are likely to be mediated by the intracellular T3 receptor, as the D-isomer RT3 and T0, which do not bind to T3 receptors, proved ineffective. The present data suggested that T3 may regulate Schwann cell functions and differentiation by transiently activating the expression of specific transcription factors.

3T3 Cells↗

PubMed2001

Partitioning of trace metals before and after biological removal of metals from sediments.

Metal removal by biological solubilization in three strongly contaminated sediments was carried out in a two-liter stirred bioreactor. Biological treatment yielded metal removal efficiencies in the range of 11-30%, 43-57%, 60-79%, 61-90%, 18-21%, 0-10% for Pb, Cu, Zn, Cd, Ni and Cr, respectively. The treated sediments were then rinsed with a NaCl solution (0.5 M), resulting in an increase by nearly 47% in Pb removal for the three sediments, while for other metals (Cu, Zn, Cd, Ni, Cr), the NaCl rinse did not seem to allow any significant increase in metal solubilization. A standard procedure of sequential selective extraction (SSE) was applied to the sediments before and after each treatment. With regard to Pb, Zn and Cd, the carbonate bound fractions (2/3 sediments) represented 18-42% of metals prior to treatment, while the iron and manganese oxides bound fraction constituted 39-60% of metals for the three sediments. Between 90 and 100% of Pb, Zn and Cd removed by the process came from the fractions bound to carbonates and from those bound to Fe and Mn oxides. The organic matter and sulfide bound fractions contained 65-72% of total Cu present before treatment and the process removed, on average, 63% Cu present in this fraction. In contrast, Ni and Cr were found mainly in the residual fractions (50-80%). Finally, this biological treatment did not solubilize Cr appreciably, while removal of Ni mostly originated from the carbonate and Fe/Mn oxides fractions (70-80%).

Carbonates↗

PubMed2001

Progesterone synthesis and myelin formation in peripheral nerves.

Progesterone is synthesized in the nervous system by neurons and glial cells. Because of their simple structure, plasticity and capacity of regeneration, peripheral nerves are particularly well suited for studying the biosynthesis, mechanisms of action and effects of the hormone. Schwann cells, the myelinating glial cells in the peripheral nervous system, synthesize progesterone in response to a diffusible neuronal signal. In peripheral nerves, the local synthesis of progesterone plays an important role in the formation of myelin sheaths. This has been shown in vivo, after cryolesion of the mouse sciatic nerve, and in vitro, in cocultures of Schwann cells and sensory neurons. Schwann cells also express an intracellular receptor for progesterone, which thus functions as an autocrine signalling molecule. Progesterone may promote myelination by activating the expression of genes coding for transcription factors (Krox-20) and/or for myelin proteins (P0, PMP22). Recently, it has been proposed that progesterone may indirectly regulate myelin formation by influencing gene expression in neurons. Steroid hormones also influence the proliferation of Schwann cells: estradiol becomes a potent mitogen for Schwann cells when levels of cAMP are elevated and glucocorticosteroids have been shown to increase the mitogenic effects of peptide growth factors.

Animals↗