24 results on '"Paillet, S."'
Search Results
2. Comparative effectiveness of gonadotropins used for ovarian stimulation during assisted reproductive technologies (ART) in France: A real-world observational study from the French nationwide claims database (SNDS)
- Author
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Grynberg, M., primary, Cedrin-Durnerin, I., additional, Raguideau, F., additional, Herquelot, E., additional, Luciani, L., additional, Porte, F., additional, Verpillat, P., additional, Helwig, C., additional, Schwarze, J.E., additional, Paillet, S., additional, Castello-Bridoux, C., additional, D'Hooghe, Thomas, additional, and Benchaïb, M., additional
- Published
- 2022
- Full Text
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3. O-113 Effectiveness and treatment cost of assisted reproduction technology for women stimulated by gonadotropin in France: A cohort study using the National Health Database
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Benchaib, M, primary, Grynberg, M, additional, Cedrin-Durnerin, I, additional, Raguideau, F, additional, Lennon, H, additional, Castello-Bridoux, C, additional, Paillet, S, additional, Porte, F, additional, Verpillat, P, additional, Van Hille, B, additional, Schwarze, J E, additional, and Borget, I, additional
- Published
- 2021
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4. Stimulation ovarienne sous gonadotrophines chez des patientes atteintes de syndrome des ovaires polykystiques
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Isnard, V., primary, Paillet, S., additional, Patin, V., additional, Lesourd-Pontonnier, F., additional, Pasquier-Pelletier, M., additional, and Dewailly, D., additional
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- 2019
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5. Long Term Outcome of Couples Undertaking their First IVF/ICSI Attempt: A French Study
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Parneix, I, primary, Arvis, P, additional, Paillet, S, additional, Longin, J, additional, Lehert, P, additional, Avril, C, additional, and Lesourd, F, additional
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- 2016
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6. Improvement of adhesion properties by control of the Rheological behavior at high strains
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Roncin, A., Paillet, S., Marin, Gérard, Billon, L., Save, M., Majeste-Labourdenne, J. C., Derail, Christophe, Physico-chimie des polymères (PCP), Centre National de la Recherche Scientifique (CNRS)-Université de Pau et des Pays de l'Adour (UPPA), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), and Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[CHIM.POLY]Chemical Sciences/Polymers ,adhesive rheol adhesion property - Abstract
International audience; This study aims to understand how the specific elastic and dissipative effects developed at large strains by branched and linear species may lead to specific and controlled adhesion properties. The adhesion properties of soft adhesive are governed to a large extend by their rheol. properties. While the linear viscoelastic properties govern the behavior at small strains, the strain hardening effects due to networking and long chain branching, are non linear viscoelastic effects obsd. at large strains, which may improve adhesion properties. The combination of strain hardening and material compliance which drives adhesion properties, may be controlled through polymer structure and macromol. design. [on SciFinder(R)]
- Published
- 2011
7. Comparative effectiveness of gonadotropins used for ovarian stimulation during assisted reproductive technologies (ART) in France: A real-world observational study from the French nationwide claims database (SNDS)
- Author
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Grynberg, M., Cedrin-Durnerin, I., Raguideau, F., Herquelot, E., Luciani, L., Porte, F., Verpillat, P., Helwig, C., Schwarze, J.E., Paillet, S., Castello-Bridoux, C., D'Hooghe, Thomas, and Benchaïb, M.
- Abstract
This comparative non-interventional study using data from the French National Health Database (Système National des Données de Santé) investigated real-world (cumulative) live birth outcomes following ovarian stimulation, leading to oocyte pickup with either originator recombinant human follicle-stimulating hormone (r-hFSH) products (alfa or beta), r-hFSH alfa biosimilars, or urinaries including mainly HP-hMG (menotropins), and marginally u-hFSH-HP (urofollitropin). Using data from 245,534 stimulations (153,600 women), biosimilars resulted in a 19% lower live birth (adjusted odds ratio (OR) 0.81, 95% confidence interval (CI) 0.76–0.86) and a 14% lower cumulative live birth (adjusted hazard ratio (HR) 0.86, 95% CI 0.82–0.89); and urinaries resulted in a 7% lower live birth (adjusted OR 0.93, 95% CI 0.90–0.96) and an 11% lower cumulative live birth (adjusted HR 0.89, 95% CI 0.87–0.91) versus originator r-hFSH alfa. Results were consistent across strata (age and ART strategy), sensitivity analysis using propensity score matching, and with r-hFSH alfa and beta as the reference group.
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- 2023
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8. PIH40 - Long Term Outcome of Couples Undertaking their First IVF/ICSI Attempt: A French Study
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Parneix, I, Arvis, P, Paillet, S, Longin, J, Lehert, P, Avril, C, and Lesourd, F
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- 2016
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9. Associative Polymers for EOR - Towards a Better Understanding and Control of Their Adsorption in Porous Media
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Rousseau, D., primary, Tabary, R., additional, Paillet, S., additional, Xu, Z., additional, Grassl, B., additional, and Desbrières, J., additional
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- 2008
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10. [Ovarian stimulation with gonadotrophins in patients with polycystic ovary syndrome].
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Isnard V, Paillet S, Patin V, Lesourd-Pontonnier F, Pasquier-Pelletier M, and Dewailly D
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- Adult, Female, France, Gestational Age, Humans, Insemination, Artificial, Ovarian Hyperstimulation Syndrome epidemiology, Ovulation Induction adverse effects, Patient Satisfaction, Pregnancy, Recombinant Proteins administration & dosage, Follicle Stimulating Hormone, Human administration & dosage, Infertility, Female etiology, Infertility, Female therapy, Ovulation Induction methods, Polycystic Ovary Syndrome complications
- Abstract
Objectives: The main objective of this study was to describe the ovulation rate in patients with polycystic ovary syndrome, treated with ovulation induction/intra-uterine insemination and follitropin alfa by gonadotrophins at a second attempt., Methods: An observational, national and multicentre study was carried out: 51 French physicians (endocrinologists, gynaecologists) participated. Eligible patients were followed according to the usual clinical practices. The primary endpoint was the number of ovulations (spontaneous or triggered). Quality of life evaluation (by FertiQoL), compliance, and patient satisfaction were secondary endpoints., Results: A total of 202 patients (mean age: 29.9 years; mean infertility: 2.9 years) were included: 78.4% met the Rotterdam definition. The ovulation rate was 93.3% (95% confidence interval [89.8; 96.8]%). At 12 weeks of gestation, 38 patients had an ongoing pregnancy. A difference of 10 points of the mean total FertiQoL score was observed between the two attempts. No patient reported missing injection. More than 9 in 10 patients said they were satisfied to very satisfied with the use of the pen injector for administration of follitropin alfa. Eight patients (4.0%) had hyperstimulation leading to cycle cancellation, and two patients (1.1%) reported ovarian hyperstimulation syndrome., Conclusions: At the second cycle of follitropin alfa stimulation, a high rate of ovulations, satisfactory compliance and tolerance profile associated with a change in quality of life were reported., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)
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- 2019
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11. A cost-effectiveness analysis comparing the originator follitropin alfa to its biosimilars in patients undergoing a medically assisted reproduction program from a French perspective.
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Grynberg M, Murphy C, Doré C, Fresneau L, Paillet S, Petrica N, Frédérique M, and Ravonimbola H
- Abstract
Objective: To assess the cost-effectiveness (CE) of the originator follitropin-α (Gonal-F) in patients undergoing a medically assisted reproduction (MAR) program in comparison to its biosimilars Bemfola and Ovaleap in a French context., Methods: A CE model was developed for France with a National Health Service (NHS) perspective. Clinical, safety, and dosage data were derived from pivotal clinical trials that compared Gonal-F to Ovaleap and Bemfola. Costs pertaining to drugs, hospitalizations, specialist visits, and examinations were retrieved from the French Programme de Médicalisation des Systèmes d'Information (PMSI) hospital database, literature review, and French clinical experts using 2017 Euro tariffs. In order to test the robustness of results, deterministic one-way sensitivity analyses were carried out on the main variables to assess the impact of treatment cost, probability of birth, ovarian hyperstimulation syndrome (OHSS) rates, and dosage., Results: The average incremental cost per live birth with OHSS and without OHSS was €259.56 and €278.39, respectively for Gonal-F compared to the pooled biosimilars (i.e., Ovaleap and Bemfola). GONAL-F had an incremental efficacy of 0.06 over the pooled biosimilars. The incremental cost-effectiveness ratio for Gonal-F with OHSS ranged from €3,274.80 to €4,877.76 compared to the pooled biosimilars, owing to the additional live births reported with Gonal-F. Sensitivity analyses also supported results from the base case analyses, with Gonal-F being cost-effective or the dominant strategy in most cases., Conclusion: Gonal-F seems to be a cost-effective strategy compared to its biosimilars Ovaleap and Bemfola, irrespective of the incidence of OHSS events, but further data are needed to confirm these results.
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- 2018
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12. Rapid and quantitative determination of critical micelle concentration by automatic continuous mixing and static light scattering.
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Paillet S, Grassl B, and Desbrières J
- Abstract
We present the rapid and quantitative characterization of ionic, non-ionic and zwitterionic surfactants based upon the combination of an automatic continuous mixing technique and static light scattering. Collection and subsequent analysis of data are both rapid and semiautomatic, which increases precision, sensitivity, and range of applicability while substantially decreasing the amount of manual intervention required by the investigator. By treating the continuous data, the entire data set may be rapidly analyzed in the context of the closed association model to determine the critical micelle concentration cmc and aggregation number Nag of a detergent; these technique are comparable in the scope and resolution currently obtainable from other conductimetric, fluorescence and surface tension techniques.
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- 2009
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13. A phase I open label study of the farnesyltransferase inhibitor CP-609,754 in patients with advanced malignant tumors.
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Moulder SL, Mahany JJ, Lush R, Rocha-Lima C, Langevin M, Ferrante KJ, Bartkowski LM, Kajiji SM, Noe DA, Paillet S, and Sullivan DM
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- Aged, Area Under Curve, Farnesyltranstransferase, Female, Humans, Inhibitory Concentration 50, Leukocytes, Mononuclear enzymology, Male, Maximum Tolerated Dose, Middle Aged, Models, Chemical, Time Factors, Alkyl and Aryl Transferases antagonists & inhibitors, Antineoplastic Agents therapeutic use, Enzyme Inhibitors therapeutic use, Imidazoles pharmacology, Neoplasms drug therapy, Quinolones pharmacology
- Abstract
Purpose: The purpose of this phase I clinical trial was to determine the maximum-tolerated dose and toxicity of CP-609,754 in patients with solid tumors refractory to standard therapies, to determine the cellular effects of CP-609,754 on its molecular target (farnesyltransferase), and to determine the recommended phase II dose (RP2D) of this agent., Experimental Design: Consenting patients with adequate bone marrow, liver, and renal function were enrolled with an accelerated dose strategy with single-patient parallel cohorts in whom the drug was given orally either once or twice daily. Once a dose-limiting toxicity was encountered or two patients developed Common Toxicity Criteria > or = grade 2 toxicities, a modified Fibonacci sequence was initiated. Blood samples were collected during cycle 1 for pharmacokinetic and pharmacodynamic analyses., Results: A total of 68 cycles of CP-609,754 was administered to 21 patients enrolled in this study. The dose escalation was from 20 mg once daily to 640 mg twice per day, and at the highest dose level, one of six patients developed a dose-limiting toxicity of grade 3 neuropathy. The drug was otherwise well tolerated, and the maximum-tolerated dose was not reached because of the large number of tablets that would have been required for additional dose escalation. Pharmacokinetic analyses showed a proportional increase in exposure with dose, rapid oral absorption, and a half-life of approximately 3 hours. Pharmacodynamic results predict a 95% maximal inhibition of peripheral blood mononuclear cell farnesyltransferase activity 2 hours postdose, on average, with a dose of 400 mg twice per day of CP-609,754., Conclusions: On the basis of the safety findings and the pharmacokinetic and pharmacodynamic analyses, the RP2D of CP-609,754 is > or =640 mg twice per day.
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- 2004
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14. Weight gain reverses bone turnover and restores circadian variation of bone resorption in anorexic patients.
- Author
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Caillot-Augusseau A, Lafage-Proust MH, Margaillan P, Vergely N, Faure S, Paillet S, Lang F, Alexandre C, and Estour B
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- 25-Hydroxyvitamin D 2 blood, Adolescent, Adult, Anorexia Nervosa blood, Biomarkers blood, Biomarkers urine, Body Mass Index, Bone Resorption, Case-Control Studies, Collagen blood, Collagen urine, Collagen Type I, Female, Humans, Osteocalcin blood, Parathyroid Hormone blood, Peptides blood, Peptides urine, Anorexia Nervosa physiopathology, Bone Remodeling, Circadian Rhythm, Weight Gain
- Abstract
Objective: The present study was conducted in order to describe the variations and circadian rhythm of biochemical markers of bone remodelling at baseline and after weight gain in patients with anorexia nervosa (AN)., Subjects: We studied 9 women (mean age 21 years, range: 16-30) with established AN who remained amenorrhoeic during the study and with a low body mass index (BMI) after refeeding and 6 female controls (mean age 20 years, range, 18-24 and BMI: 20.6 +/- 1.1 kg/m2). Refeeding was not associated with any other intervention or treatment, especially oestrogen replacement or hormonal contraception. Serum levels of oestradiol remained below 70 pmol/l before and after refeeding., Measurements: During the study, PTH and 25-hydroxyvitamin D measurements were performed. Markers of bone formation: serum intact osteocalcin (iBGP) and serum intact BGP + fragments (iBGP+F) and markers of bone resorption: urine C-teloptide of type I collagen (uCTX) and serum C-telopeptide ofvtype 1 collagen (s-CTX) were measured., Results: At baseline, PTH and 25 OH-vitamin D concentrations were within the normal range in AN patients and no significant variation was observed after refeeding. Bone formation markers were found to be significantly different at baseline between AN patients and controls. After refeeding, iBGP and iBGP+F levels increased by 172% and 154%, respectively, to values no different from controls. Intact BGP and iBGP+F exhibited a significant circadian variation in controls (P < 0.05 and P < 0.002, respectively), whereas we did not find any such circadian rhythm in AN patients. After refeeding no significant circadian variation was observed; however, iGBP+F tended to peak in early morning and exhibited a nadir in the afternoon. At baseline, sCTX was 2-fold higher in AN patients than in controls. After weight gain sCTX decreased significantly and reached control values. Refeeding induced a non-significant 40% decrease in uCTX. We found positive correlations between uCTX and the 24-h mean value of sCTX levels (r2 = 0.93, P < 0.0001) and between uCTX and the mean value of sCTX peak levels at 0800 h (r2 = 0.65, P < 0.0003). Serum CTX exhibited a significant circadian variation in controls (P < 0.001) with a peak at 0800 h and a nadir at 1600 h with a 60% decrease between peak and nadir values. We found that anorexia nervosa suppressed the sCTX circadian variation which was restored by refeeding. We found a significant non-linear relationship between BMI and sCTX/iBGP ratio in AN (r2 = 0.6, P < 0.0001), thus illustrating the influence of nutritional status on bone remodelling., Conclusions: In this study we found that weight gain, related to refeeding only, reversed the anorexia nervosa-induced uncoupling of bone remodelling and restored circadian variation of a bone resorption marker.
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- 2000
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15. [Diagnosis and prevention of candidiasis in intensive care patients].
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Leon A, Toubas D, Renard P, Suinat JL, Raclot P, Cousson J, Paillet S, and Pinon JM
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- Adult, Aged, Aged, 80 and over, Amphotericin B therapeutic use, Candidiasis prevention & control, Clinical Protocols, Cross Infection prevention & control, Digestive System microbiology, Esophagitis diagnosis, Esophagitis prevention & control, Female, Humans, Male, Middle Aged, Randomized Controlled Trials as Topic, Risk Factors, Candidiasis diagnosis, Cross Infection diagnosis, Intensive Care Units
- Abstract
Invasive candidiasis infections remain a major complication in I.C.U. patients. Numerous attempts have been made to evaluate potential prophylactic methods. Various agents have been tested. Gastrointestinal tract constitutes one of the major reservoirs for Candida species. One major problem is the difficulty in establishing an accurate, early, diagnosis of invasive fungal infection. A prospective randomized, controlled blind study was performed to assess the ability of oral Amphotericin B to prevent candidiasis in selected I.C.U. patients. Fifty one patients with serious infection and antibiotherapy were randomized to receive either oral Amphotericin B (2 g/day) or placebo, and observed until discharge. All patients were screened weekly for sites culture positive, sero-conversion and oesophagitis. Invasive candidiasis developed in 45% of patients receiving Amphotericin B compared with 41% receiving placebo. C. Albicans persists in the surveillance cultures. However a significant reduction of the colonization by the yeasts and a significant reduction of oesophagitis was demonstrated among the Amphotericin B group. No benefit was found in the total number of hospital days. Digestive decontamination can be successfully managed by Amphotericin B in I.C.U. patients but failed to prevent invasive candidiasis.
- Published
- 1990
16. Hamster hepatocyte-mediated activation of procarcinogens to mutagens in the L5178Y/TK mutation assay.
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Amacher DE and Paillet SC
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- Amines pharmacology, Animals, Cells, Cultured, Cricetinae, Hybrid Cells, Leukemia L5178 genetics, Liver, Mutagenicity Tests, Nitrosamines pharmacology, Polycyclic Compounds pharmacology, Thymidine Kinase genetics, Carcinogens pharmacology, Mutagens pharmacology
- Abstract
Eight procarcinogens including three nitrosamines, three polycyclic hydrocarbons, and two aromatic amines were tested for mutagenic potential at the thymidine kinase (TK) locus in L5178Y mouse lymphoma cells co-cultivated with viable hamster hepatocytes. All eight chemicals produced substantial mutagenic activity as indicated by increased trifluorothymidine resistance in L5178Y cells treated in the presence of hepatocytes. Mutagenic responses to benzo[alpha]pyrene, 3-methylcholanthrene, N-nitrosodiethylamine, and N-nitrosodipropylamine first increased, then plateaued within the range of mutagen concentrations tested, while consistent dose-dependent increases in mutant frequencies were observed following 2-aminoanthracene, 2-aminofluorene, or N-nitrosodimethylamine treatments. The relatively flat portions of the mutant frequency curves for benzo[alpha]pyrene and 3-methylcholanthrene coincided with maximum chemical solubility as obvious from visible or microscopically detectable precipitate. These hamster cells readily facilitated the metabolism of 1,2-benzanthracene to a detectable mutagen and were especially competent in the activation of the two aromatic amines. Thus, cultured hamster hepatocytes can activate a variety of chemical carcinogens including polycyclic hydrocarbons to mutagens in a whole cell-mediated in vitro assay using L5178Y/TK+/- cells as the target organism.
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- 1982
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17. Trifluorothymidine resistance and colony size in L5178Y/TK +/- cells treated with methyl methanesulfonate.
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Amacher DE and Paillet SC
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- Animals, Cell Division drug effects, Cell Line, Cell Survival drug effects, Drug Resistance, Genetic Variation, Karyotyping, Lymphoma, Mice, Mutation drug effects, Thymidine Kinase metabolism, Clone Cells cytology, Methyl Methanesulfonate pharmacology, Thymidine analogs & derivatives, Trifluridine pharmacology
- Abstract
L5178Y/TK +/- cells treated with methyl methanesulfonate (MMS) were allowed to recover for 0,48,96,144, or 240 hours, and were then plated in soft-agar medium containing trifluorothymidine (TFT). Dose-dependent and consistent increases in the frequency of TFTR cells were observed after each of the 48-240-hour expression periods through the counting of predominantly large, mutant colonies. Size distributions of soft-agar colonies from either MMS-treated or control cells were bimodal in the presence, and unimodal in the absence, of TFT. An increase of small, presumptive TFTR colonies with either increasing MMS concentration or decreasing recovery time was probably a manifestation of chemical toxicity, for a similar increase in small-colony number was observed in the absence of TFT when cells were cloned immediately after MMS treatment, when no induced mutants were yet detectable. Recloning experiments with 22 small-colony-derived cell lines revealed that, with one exception, small-colony morphology was not a heritable trait. While all large- and some small-colony-derived stocks from MMS-treated cells were of the phenotypically stable TK-/- type; spontaneous small TFTR colonies generally were not, their occurrence being directly correlated with serum concentration. No aneuploidy was evident in MMS-treated cell lines several generations after isolation as small TFTR colonies. These results suggest that delayed MMS cytotoxicity in TK +/- cells can temporarily produce increased physiological resistance to TFT in some cells, giving rise to secondary populations of small-colony TFTR variants.
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- 1981
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18. Metabolic activation of 3-methylcholanthrene and benzo(a)pyrene to mutagens in the L5178Y/TK assay by cultured embryonic rodent cells.
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Amacher DE, Paillet SC, and Zelljadt I
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- Animals, Biotransformation, Cell Survival, Cells, Cultured, Cricetinae, Culture Media, Dose-Response Relationship, Drug, Embryo, Mammalian, Male, Mice, Rats, Benzopyrenes metabolism, Methylcholanthrene metabolism, Mutagenicity Tests methods, Mutagens
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- 1982
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19. Point mutations at the thymidine kinase locus in L5178Y mouse lymphoma cells. II. Test validation and interpretation.
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Amacher DE, Paillet SC, Turner GN, Ray VA, and Salsburg DS
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- Animals, Biotransformation, Carcinogens pharmacology, Cell Line, Cell Survival, Dose-Response Relationship, Drug, Mice, Mutagenicity Tests, Research Design, Solvents pharmacology, Leukemia L5178 enzymology, Leukemia, Experimental enzymology, Mutation, Thymidine Kinase genetics
- Abstract
The L5178Y Mouse Lymphoma TK assay was studied extensively to determine if this mammalian cell assay for gene mutations at the thymidine kinase (TK) locus could provide valid, interpretable determinations of mutagenic potential, and whether this information is of value in the safety evaluation of chemicals. We first determined that test-derived TFTR mutants were phenotypically stable, possessing little or no thymidine kinase activity as measured by labeled thymidine uptake, but demonstrating 100% cross resistance to bromodeoxyuridine. Common solvent vehicles such as acetone, dimethylsulfoxide and ethanol were shown to produce little cytotoxicity and no mutagenic activity when present at 1% levels. Out of a total of 10 noncarcinogens tested, all were negative when results were analyzed by a 2-sample loge t test on control and treated mutant count means. Of the 13 putative animal carcinogens tested, 10 were positive, 2 were negative (auramine O and sodium phenobarbital), and 1 showed sporadic activity (hydrazine sulfate) in the TK assay on the basis of test-derived t statistics. 2 compounds, 1,2-epoxybutane and ICR 191, which have been described as Ames positive non-carcinogens, were also positive in the TK assay. Although this sampling of a total of 29 compounds is insufficient for precise estimations of expected false-positive or false-negative frequencies, these data indicate the TK assay can be expected to detect a majority of carcinogens as mutagens including some missed by more established point-mutation assays.
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- 1980
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20. Induction of trifluorothymidine-resistant mutants by metal ions in L5178Y/TK+/- cells.
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Amacher DE and Paillet SC
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- Animals, Arsenic pharmacology, Cadmium pharmacology, Dose-Response Relationship, Drug, L Cells metabolism, Magnesium pharmacology, Mice, Mutagenicity Tests, Nickel pharmacology, Platinum pharmacology, Zinc pharmacology, Metals pharmacology, Mutagens
- Abstract
7 inorganic metal salts including magnesium chloride, cadmium chloride, nickel chloride, zinc chloride, cobalt(II) chloride, lead acetate, sodium arsenate, and the platinum coordination complex, trans-platinum(II) diaminedichloride, were tested for the potential to induce trifluorothymidine-resistant (TFTRes) mutants in L5178Y/TK+/- mouse lymphoma cell by directly exposing cells to varied doses of each compound for 3 h. Of these 8 chemicals, cadmium chloride, nickel chloride, and trans-platinum(II) diaminedichloride consistently produced dose-related increases in the absolute number of TFTRes mutants as well as increases in mutation frequencies at compound concentrations permitting greater than 20% survival. Trans-platinum(II) diaminedichloride was a particularly effective mutagen, comparable to the direct-acting mutagen, methyl methanesulfonate. 15 representative TFTRes mutant cell clones derived from cultures originally treated with either the cadmium, or nickel, or platinum compounds were first grown out for 7 days in nonselective medium, then verified as phenotypically stable TK-/- mutants by demonstrated cross-resistance to 5-bromodeoxyuridine and 100% sensitivity to the folate antagonist methotrexate in THMG medium. These results demonstrate that the soluble salts of 2 metals reported to be human carcinogens and 1 noble metal complex known to bind DNA are all mammalian cell mutagens as well.
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- 1980
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21. Ascorbate is detectably mutagenic in the L5178Y TK+/- cell mutation assay.
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Amacher DE and Paillet SC
- Subjects
- Animals, Cell Line, Cell Survival drug effects, Culture Media, Dose-Response Relationship, Drug, Lymphoma pathology, Mice, Mutagenicity Tests methods, Mutation, Neoplasms, Experimental pathology, Sodium, Ascorbic Acid toxicity, Lymphoma genetics, Mutagens, Neoplasms, Experimental genetics, Thymidine Kinase genetics
- Abstract
Both sodium ascorbate and ascorbic acid were tested at millimolar concentrations in the mouse lymphoma L5178Y TK+/- cell for chemically-induced cytotoxicity and the induction of gene mutations at the thymidine kinase locus as detected by increased trifluorothymidine-resistance. Neither chemical caused any dose-related increases in trifluorothymidine resistance, even at toxic levels. Increased hydrogen ion concentration was not itself a contributing factor to ascorbic acid toxicity. Ascorbate toxicity was due to products formed in vitro in the absence of cells via chemical reactions with medium components. The formation or persistence of these toxic substances could be prevented by co-incubation with catalase prior to the addition of L5178Y cells. These results suggest that ascorbic acid would not be a mammalian cell mutagen normal physiological conditions.
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- 1981
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22. The metabolism of N-acetyl-2-aminofluorene to a mutagen in L5178Y/TK+/-mouse lymphoma cells.
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Amacher DE, Paillet SC, and Elliott JA
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- Animals, Dose-Response Relationship, Drug, Mice, Mutagenicity Tests, Time Factors, 2-Acetylaminofluorene metabolism, Biotransformation, Leukemia L5178 metabolism, Leukemia, Experimental metabolism, Mutagens metabolism
- Abstract
Direct treatment of L5178Y mouse lymphoma TK+/- cells with N-acetyl-2-aminofluorene (AAF) from two commercial sources produced small, but reproducible increases in mutant frequency over background in the absence of exogenous microsomal enzymes. Unlike most direct-acting mutagens which typically produce regular, dose-dependent increases in mutant frequency; AAF treatment caused very slight dose-related increases or a saturation phenomenon which could be overcome by increased exposure time. Direct mutagenicity following prolonged (24h) exposure was confirmed when a third highly purified (99.9%) AAF sample was tested. Microsomal enzyme analyses of disrupted L5178Y cell preparations revealed negligible benzo[a]pyrene hydroxylase but measurable AAF-N-hydroxylase activity. These data demonstrate that L5178Y mouse lymphoma cells are capable of limited metabolism of AAF to an active mutagen.
- Published
- 1981
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23. The activation of procarcinogens to mutagens by cultured rat hepatocytes in the L5178Y/TK mutation assay.
- Author
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Amacher DE and Paillet SC
- Subjects
- Animals, Biotransformation, Cell Separation, Cells, Cultured, Male, Nitrosamines metabolism, Polycyclic Compounds metabolism, Rats, Rats, Inbred Strains, Liver metabolism, Mutagenicity Tests methods, Mutagens metabolism
- Abstract
Whole cell preparations derived from collagenase-treated rat liver were cocultivated overnight with stationary (non-shaking) cultures of L5178Y/TK+/- cells in the presence of 8 different chemicals selected as representative aromatic amine, polycyclic hydrocarbon, or nitrosamine procarcinogens. When tested in the presence of hepatocytes, 2-aminoanthracene, 2-aminofluorene, N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodipropylamine, 3-methylcholanthrene, and benzo[a]pyrene all produced substantial dose-dependent increases in trifluorothymidine-resistant variants compared to solvent controls after 20 h total exposure time. Only N-nitrosodipropylamine (DPrN) and N-nitrosodiethylamine (DEN) produced any dose-related mutagenic activity in similar experiments where hepatocytes were omitted; however, the response for the DPrN was quite variable at high doses in the absence of hepatocytes and the mutagenic response for the DEN was consistently enhanced at all dose levels by the presence of hepatocytes. Benzanthracene was not active in the presence of whole hepatocytes, even when tested with cells from a rat pretreated 24 h earlier with 20 mg/kg benzanthracene. Excepting benzanthracene, these data suggest that rat hepatocytes can be used to active 3 types of procarcinogens to mutagens in the L5178Y/TK gene mutation assay.
- Published
- 1983
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24. Point mutations at the thymidine kinase locus in L5178Y mouse lymphoma cells. I. Application to genetic toxicological testing.
- Author
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Amacher DE, Paillet S, and Ray VA
- Subjects
- Animals, Carcinogens metabolism, Cell Line, Evaluation Studies as Topic, Genes, Leukemia, Experimental enzymology, Mice, Mutagens metabolism, Drug Evaluation, Preclinical methods, Genetic Techniques, Mutation, Thymidine Kinase genetics
- Abstract
We have systematically evaluated the mouse lymphoma TK+/- leads to TK-/- mutagenesis assay to determine if this somatic-cell test system would be a useful addition to the routine screening battery already used in our laboratory for the detection of chemical mutagens. During these investigations we observed that, with certain modifications of the basic assay, mutagenicity data could be obtained in as little as 9 days once the relative cytotoxic properties of the test substance were known. By improving the culturing conditions, we were able to reduce the serum requirements by as much as 50--75% without appreciably altering either cell viability or the recovery of chemically-induced mutants. Phenotypic stability of test-derived trifluorothymidine resistant (TFTR) mutants was confirmed by demonstrating cross-resistance to bromodeoxyuridine and concomitant sensitivity to methotrexate (THMG) in TFTR cells grown for 20 generations under non-selective conditions. While reduced growth rates resulting from temporary cell-division delay in treated cells is probably not a contributing factor to the observed mutation frequencies, only TFTR colonies which formed large distinct colonies in the presence of trifluorothymidine were clearly phenotypically stable mutants when spontaneous mutants were isolated and verified. When a non-mutagen, a weak mutagen, and a well-established mutagen were compared at equitoxic doses under these modified conditions, clear quantitative differences were seen in the respective mutation frequencies induced by these 3 types of agents. With these technical modifications, we feel this assay is both reliable and amenable to the screening of diverse chemical compounds for point-mutational activity in a mammalian cell.
- Published
- 1979
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