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1.
Anal Chem ; 88(7): 3585-91, 2016 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-26926765

RESUMEN

Nonpolar anabolic steroids are doping agents that typically do not provide strong signals by electrospray ionization-mass spectrometry (ESI-MS) owing especially to the low polarity of the functional groups present. We have investigated the addition of anions, in ammonium salt form, to anabolic steroid samples as ionization enhancers and have confirmed that lower instrumental limits of detection (as low as 10 ng/mL for fluoxymesterone-M) are obtained by fluoride anion attachment mass spectrometry, as compared to ESI(+)/(-) or atmospheric pressure photoionization (APPI)(+). Moreover, collision-induced decomposition (CID) spectra of precursor fluoride adducts of the bifunctional steroid "reduced pregnenolone" (containing two hydroxyl groups) and its d4-analogue provide evidence of regiospecific decompositions after attachment of fluoride anion to a specific hydroxyl group of the steroid. This type of charting of specific CID reaction pathways can offer value to selected reaction monitoring experiments (SRM) as it may result in a gain in selectivity in detection as well as in improvements in quantification.


Asunto(s)
Compuestos de Amonio/química , Esteroides/análisis , Esteroides/química , Aniones/química , Sales (Química)/química , Espectrometría de Masa por Ionización de Electrospray , Estereoisomerismo
2.
Anal Bioanal Chem ; 406(4): 1209-19, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23900670

RESUMEN

Metabonomics has become a very valuable tool and many research fields rely on results coming out from this combination of analytical techniques, chemometric strategies, and biological interpretation. Moreover, the matrices are more and more complex and the implications of the results are often of major importance. In this context, the need for pertinent validation strategies comes naturally. The choice of the appropriate chemometric method remains nevertheless a difficult task due to particularities such as: the number of measured variables, the complexity of the matrix and the purposes of the study. Consequently, this paper presents a detailed metabonomic study on human urine with a special emphasis on the importance of assessing the data's quality. It also describes, step by step, the statistical tools currently used and offers a critical view on some of their limits. In this work, 29 urine samples among which 15 samples obtained from tetrahydrocannabinol (delta-9-tetrahydrocannabinol)-consuming athletes, 5 samples provided by volunteers, and 9 samples obtained from athletes were submitted to untargeted analysis by means of ultra high-pressure liquid chromatography-electrospray ionization-time-of-flight mass spectrometry. Next, the quality of the obtained data was assessed and the results were compared to those found in databases. Then, unsupervised (principal component analysis (PCA)) and supervised (ANOVA/PCA, partial least-square-discriminant analysis (PLS-DA), orthogonal PLS-DA) univariate and multivariate statistical methods were applied.


Asunto(s)
Minería de Datos/estadística & datos numéricos , Dronabinol/orina , Metabolómica , Cromatografía Líquida de Alta Presión , Doping en los Deportes , Dronabinol/metabolismo , Humanos , Análisis de Componente Principal , Espectrometría de Masa por Ionización de Electrospray
3.
J Strength Cond Res ; 28(4): 958-63, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24104542

RESUMEN

Competitive swimmers regularly perform apnea series with or without fins as part of their training, but the ergogenic and metabolic repercussions of acute and chronic apnea have not been examined. Therefore, we aimed to investigate the cardiovascular, lactate, arterial oxygen saturation and hormonal responses to acute apnea in relation to performance in male swimmers. According to a randomized protocol, 15 national or regional competitive swimmers were monitored while performing four 100-m freestyle trials, each consisting of four 25-m segments with departure every 30 seconds at maximal speed in the following conditions: with normal frequency breathing with fins (F) and without fins (S) and with complete apnea for the four 25-m segments with (FAp) and without fins (SAp). Heart rate (HR) was measured continuously and arterial oxygen saturation, blood, and saliva samples were assessed after 30 seconds, 3 minutes, and 10 minutes of recovery, respectively. Swimming performance was better with fins than without both with normal frequency breathing and apnea (p < 0.001). Apnea induced no change in lactatemia, but a decrease in arterial oxygen saturation in both SAp and FAp (p < 0.001) was noted and a decrease in HR and swimming performance in SAp (p < 0.01). During apnea without fins, performance alteration was correlated with bradycardia (r = 0.63) and arterial oxygen desaturation (r = -0.57). Saliva dehydroepiandrosterone was increased compared with basal values whatever the trial (p ≤ 0.05), whereas no change was found in saliva cortisol or testosterone. Further studies are necessary to clarify the fin effect on HR and performance during apnea swimming.


Asunto(s)
Apnea/fisiopatología , Rendimiento Atlético/fisiología , Lactatos/sangre , Consumo de Oxígeno/fisiología , Natación/fisiología , Enfermedad Aguda , Análisis de Varianza , Atletas , Deshidroepiandrosterona/análisis , Ensayo de Inmunoadsorción Enzimática , Frecuencia Cardíaca/fisiología , Humanos , Hidrocortisona/metabolismo , Masculino , Oximetría , Educación y Entrenamiento Físico/métodos , Medición de Riesgo , Testosterona/análisis , Factores de Tiempo , Adulto Joven
4.
Electrophoresis ; 32(12): 1444-6, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21563188

RESUMEN

We report here observations clearly demonstrating that gloves can have a deleterious impact on an IEF experiment. These observations were made during the practice of analyses for anti-doping control of erythropoietin. We show that the wearing of nitrile gloves to apply the catholyte strip onto the IEF gel may be responsible for dramatic distortions in the pattern of this hormone. These observations point out that gloves must not be considered only as protective items but also as possible factors in an analytic process.


Asunto(s)
Guantes Protectores , Focalización Isoeléctrica/normas , Nitrilos/química , Artefactos , Análisis de Falla de Equipo , Eritropoyetina/química , Eritropoyetina/aislamiento & purificación , Humanos , Reproducibilidad de los Resultados
5.
Anal Bioanal Chem ; 399(5): 1835-43, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21170520

RESUMEN

Tetracosactide (Synacthen), a synthetic analogue of adrenocorticotropic hormone (ACTH), can be used as a doping agent to increase the secretion of glucocorticoids by adrenal glands. The only published method for anti-doping control of this drug in plasma relies on purification by immunoaffinity chromatography and LC/MS/MS analysis. Its limit of detection is 300 pg/mL, which corresponds to the peak value observed 12 h after 1 mg Synacthen IM administration. We report here a more sensitive method based on preparation of plasma by cation exchange chromatography and solid-phase extraction and analysis by LC/MS/MS with positive-mode electrospray ionization using 7-38 ACTH as internal standard. Identification of Synacthen was performed using two product ions, m/z 671.5 and m/z 223.0, from the parent [M + 5H](5+) ion, m/z 587.4. The recovery was estimated at 70%. A linear calibration curve was obtained from 25 to 600 pg/mL (R² > 0.99). The lower limit of detection was 8 pg/mL (S/N > 3). The lower limit of quantification was 15 pg/mL (S/N > 10; CV% < 20%). The performance of the method was illustrated by an 8-h kinetic analysis of plasma samples from nine subjects submitted to IM injections of either Synacthen® (five subjects) or Synacthen® Depot, the slow-release form of the drug (four subjects). Concentrations of Synacthen between 16 and 310 pg/mL were observed. A sensitive method for quantitation of Synacthen in plasma is proposed for anti-doping control analyses.


Asunto(s)
Cosintropina/sangre , Cromatografía por Intercambio Iónico , Cromatografía Liquida , Humanos , Espectrometría de Masas , Sensibilidad y Especificidad , Extracción en Fase Sólida
6.
Mol Ther ; 17(10): 1754-60, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19568222

RESUMEN

Ex vivo gene therapy is an interesting alternative to orthotopic liver transplantation (OLT) for treating metabolic liver diseases. In this study, we investigated its efficacy and biosafety in nonhuman primates. Hepatocytes isolated from liver lobectomy were transduced in suspension with a bicistronic liver-specific lentiviral vector and immediately autotransplanted (SLIT) into three cynomolgus monkeys. The vector encoded cynomolgus erythropoietin (EPO) and the conditional suicide gene herpes simplex virus-thymidine kinase (HSV-TK). Survival of transduced hepatocytes and vector dissemination were evaluated by detecting transgene expression and vector DNA. SLIT was safely performed within a day in all three subjects. Serum EPO and hematocrit rapidly increased post-SLIT and their values returned to baseline within about 1 month. Isoforms of EPO detected in monkeys' sera differed from the physiological renal EPO. In liver biopsies at months 8 and 15, we detected EPO protein, vector mRNA and DNA, demonstrating long-term survival and functionality of transplanted lentivirally transduced hepatocytes. Valganciclovir administration resulted in complete ablation of the transduced hepatocytes. We demonstrated the feasibility and biosafety of SLIT, and the long term (>1 year) functionality of lentivirally transduced hepatocytes in nonhuman primates. The HSV-TK/valganciclovir suicide strategy can increase the biosafety of liver gene therapy protocols by safely and completely ablating transduced hepatocytes on demand.


Asunto(s)
Terapia Genética/métodos , Hepatocitos/virología , Lentivirus/genética , Transducción Genética/métodos , Animales , Antivirales/farmacología , Western Blotting , Línea Celular , Células Cultivadas , Eritropoyetina/genética , Eritropoyetina/fisiología , Ganciclovir/análogos & derivados , Ganciclovir/farmacología , Vectores Genéticos/genética , Células HeLa , Hepatocitos/citología , Hepatocitos/efectos de los fármacos , Humanos , Hepatopatías/terapia , Macaca fascicularis , Masculino , Reacción en Cadena de la Polimerasa , Simplexvirus/genética , Timidina Quinasa/genética , Timidina Quinasa/fisiología , Valganciclovir , Proteínas Virales/genética , Proteínas Virales/fisiología
7.
Methods Mol Biol ; 536: 213-9, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19378060

RESUMEN

Nonspecific interactions between blotted proteins and unrelated secondary antibodies generate false positives in immunoblotting techniques. Some procedures have been developed to reduce this adsorption but they may work in specific applications and be ineffective in other ones. "Double-blotting" has been developed to overcome this problem. It consists of interpolating a second blotting step between the usual probings of the blot membrane with the primary antibody and the secondary antibodies. This step, by isolating the primary antibody from the interfering proteins, guarantees the specificity of the probing with the secondary antibody. This method has been developed for the study of erythropoietin in concentrated urine since a strong nonspecific binding of biotinylated secondary antibodies to some urinary proteins is observed using classical immunoblotting protocols. However, its concept makes it usable in other applications that come up against this kind of problem. This method is expected to be especially useful for investigating proteins that are present in minute amounts in complex biological media.


Asunto(s)
Anticuerpos/inmunología , Especificidad de Anticuerpos , Immunoblotting/métodos , Doping en los Deportes , Eritropoyetina/análisis , Humanos , Immunoblotting/instrumentación , Unión Proteica
8.
Clin J Sport Med ; 19(4): 311-5, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19638826

RESUMEN

OBJECTIVES: Recombinant erythropoietin has a strong impact on aerobic power and is therefore one of the most potent doping agents in endurance sports. The anti-doping control of this synthetic hormone relies on the detection, in the urine, of its isoelectric pattern, which differs from that of the corresponding natural hormone, the latter being typically more acidic than the former. However, a small number of natural urinary patterns, referred to as "atypical patterns," are less acidic than the dominant form. Based on anecdotal evidence, the occurrence of such patterns seems to be related to particular strenuous exercises. This study aimed to demonstrate this relation using a strenuous exercise protocol. DESIGN: Seven athletes took part in a training protocol including a series of supramaximal short-duration exercises. Urine and blood samples were collected throughout the protocols. SETTINGS: World Cycling Center, Aigle, Switzerland, and research laboratories. PARTICIPANTS: Seven top-level athletes (cyclists) were involved in this study. MAIN OUTCOME MEASURES: Erythropoietin (EPO) isoelectric patterns were obtained by submitting blood and urine samples to isoelectric focusing. Additional protein dosages were performed. RESULTS: Supramaximal short-duration exercises induced the transformation of typical urinary natural EPO patterns into atypical ones. None of the obtained atypical patterns fulfilled the 3 criteria mandatory for reporting an adverse analytical finding. Serum EPO patterns were not affected by the exercises that caused the transformation of urinary patterns. CONCLUSION: An exercise-induced transient renal dysfunction is proposed as a hypothetic explanation for these observations that rely on parallel investigations of proteinuria in the same samples.


Asunto(s)
Eritropoyetina/sangre , Eritropoyetina/orina , Ejercicio Físico/fisiología , Detección de Abuso de Sustancias/métodos , Adolescente , Adulto , Doping en los Deportes , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Focalización Isoeléctrica , Masculino , Proteínas Recombinantes , Suiza , Adulto Joven
9.
Int J Biol Macromol ; 41(3): 354-7, 2007 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-17540444

RESUMEN

By adding a step of immunoaffinity to the method we had previously developed for analysing erythropoietin (EPO) in urine, we were able to study the isoelectric profiles of this hormone in human serum samples. This method was sensitive enough to investigate samples presenting physiological levels of this hormone. Comparison with the corresponding profiles in urine showed that natural EPO was systematically more acidic in urine. The acidification process, which was not patent in the non-human primate Cynomolgus macaque, clearly also affected recombinant EPO when injected into humans. This process was unrelated to any enzymatic activity in urine since the incubation of natural or recombinant EPO in urine induced no transformation of their isoelectric profiles. The nature and mechanism of the structural modifications occurring during the renal handling of this hormone remain to be investigated.


Asunto(s)
Eritropoyetina/sangre , Eritropoyetina/orina , Animales , Humanos , Focalización Isoeléctrica , Punto Isoeléctrico , Macaca fascicularis , Proteínas Recombinantes , Especificidad de la Especie
10.
Haematologica ; 91(8): 1143-4, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16870547

RESUMEN

This study appraised the veracity of claims that athletes can evade doping controls by injecting microdoses of recombinant human erythropoietin (rHuEPO), which rapidly disappear from the circulation. We confirmed that microdosing can reduce the window of detection to as little as 12-18 hours post-injection, suggesting that authorities must adopt appropriate counter measures.


Asunto(s)
Doping en los Deportes , Eritropoyetina/sangre , Eritropoyetina/farmacología , Deportes , Relación Dosis-Respuesta a Droga , Eritropoyetina/administración & dosificación , Eritropoyetina/farmacocinética , Humanos , Inyecciones Intravenosas , Tasa de Depuración Metabólica , Proteínas Recombinantes , Sensibilidad y Especificidad
11.
J Appl Physiol (1985) ; 100(1): 203-11, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16179396

RESUMEN

The efficiency of "living high, training low" (LHTL) remains controversial, despite its wide utilization. This study aimed to verify whether maximal and/or submaximal aerobic performance were modified by LHTL and whether these effects persist for 15 days after returning to normoxia. Last, we tried to elucidate whether the mechanisms involved were only related to changes in oxygen-carrying capacity. Eleven elite middle-distance runners were tested before (Pre), at the end (Post1), and 15 days after the end (Post2) of an 18-day LHTL session. Hypoxic group (LHTL, n = 5) spent 14 h/day in hypoxia (6 nights at 2,500 m and 12 nights at 3,000 m), whereas the control group (CON, n = 6) slept in normoxia (1,200 m). Both LHTL and CON trained at 1,200 m. Maximal oxygen uptake and maximal aerobic power were improved at Post1 and Post2 for LHTL only (+7.1 and +3.4% for maximal oxygen uptake, +8.4 and +4.7% for maximal aerobic power, respectively). Similarly oxygen uptake and ventilation at ventilatory threshold increased in LHTL only (+18.1 and +12.2% at Post1, +15.9 and +15.4% at Post2, respectively). Heart rate during a 10-min run at 19.5 km/h decreased for LHTL at Post2 (-4.4%). Despite the stimulation of erythropoiesis in LHTL shown by the 27.4% increase in serum transferrin receptor and the 10.1% increase in total hemoglobin mass, red cell volume was not significantly increased at Post1 (+9.2%, not significant). Therefore, both maximal and submaximal aerobic performance in elite runners were increased by LHTL mainly linked to an improvement in oxygen transport in early return to normoxia and probably to other process at Post2.


Asunto(s)
Altitud , Eritropoyesis/fisiología , Ejercicio Físico/fisiología , Resistencia Física/fisiología , Esfuerzo Físico/fisiología , Desempeño Psicomotor , Carrera/fisiología , Adaptación Fisiológica/fisiología , Adulto , Aerobiosis/fisiología , Humanos , Aptitud Física/fisiología
12.
Med Sci Sports Exerc ; 38(8): 1410-7, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16888453

RESUMEN

PURPOSE: Altitude training is popular among athletes to augment oxygen delivery capabilities to tissues and to improve physical performance. Hypoxia inducible factor-1 (HIF-1) controls the expression of several genes' encoding involved in physiological responses towards reduced oxygen availability, in particular by increasing serum erythropoietin (EPO). It may be involved in the individual variability for erythropoietic markers and/or sea-level performance of athletes using altitude during their training. Therefore, we investigated whether, before training, evolutions of hif-1alpha and ahif (HIF-1alpha natural antisense) transcript amounts and HIF-1alpha protein quantities in leukocytes measured during an acute hypoxia normobaric test (3 h at 3000 m at rest) could allow to predict poor and good responders for hematological markers after a "living high-training low" protocol. METHODS: Eighteen elite swimmers were divided into two groups that followed a 13-d training program: "living low-training low" (1200 m) (LL) or "living high (2500-3000 m)-training low (1200 m)" (LH). RESULTS: During the initial hypoxia test, a strong interindividual variability in the amounts of HIF-1alpha mRNA, aHIF transcript, and HIF-1alpha protein was observed in athlete leukocytes (after vs before): -82%/+396%, -100%/+229%, and -100%/+633%, respectively. After the test, serum erythropoietin concentration was increased (11.2 +/- 0.8 vs 9.8 +/- 0.8 IU.L(-1); +18%, P = 0.01). After the training protocol, total red cell volume (+7.6%, P = 0.04) and circulating hemoglobin amount (48.8 +/- 2.8 vs 45.5 +/- 3.0 mmol; i.e., +7.9%, P = 0.02) were significantly augmented in LH. CONCLUSION: We conclude that hif-1alpha gene expression quantification in leukocytes after a 3-h hypoxia test performed before training does not predict poor and good responder athletes to "living high-training low" model.


Asunto(s)
Altitud , Eritropoyesis/fisiología , Factor 1 Inducible por Hipoxia/metabolismo , Leucocitos/metabolismo , Resistencia Física/fisiología , Natación/fisiología , Volumen de Eritrocitos , Femenino , Expresión Génica , Hemoglobinas/análisis , Humanos , Factor 1 Inducible por Hipoxia/genética , Masculino , Consumo de Oxígeno/fisiología , Educación y Entrenamiento Físico , Reacción en Cadena de la Polimerasa , Intercambio Gaseoso Pulmonar , ARN/análisis , Estadísticas no Paramétricas
13.
PLoS One ; 11(6): e0156786, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27253728

RESUMEN

Mont Blanc, the summit of Western Europe, is a popular but demanding high-altitude ascent. Drug use is thought to be widespread among climbers attempting this summit, not only to prevent altitude illnesses, but also to boost physical and/or psychological capacities. This practice may be unsafe in this remote alpine environment. However, robust data on medication during the ascent of Mont Blanc are lacking. Individual urine samples from male climbers using urinals in mountain refuges on access routes to Mont Blanc (Goûter and Cosmiques mountain huts) were blindly and anonymously collected using a hidden automatic sampler. Urine samples were screened for a wide range of drugs, including diuretics, glucocorticoids, stimulants, hypnotics and phosphodiesterase 5 (PDE-5) inhibitors. Out of 430 samples analyzed from both huts, 35.8% contained at least one drug. Diuretics (22.7%) and hypnotics (12.9%) were the most frequently detected drugs, while glucocorticoids (3.5%) and stimulants (3.1%) were less commonly detected. None of the samples contained PDE-5 inhibitors. Two substances were predominant: the diuretic acetazolamide (20.6%) and the hypnotic zolpidem (8.4%). Thirty three samples were found positive for at least two substances, the most frequent combination being acetazolamide and a hypnotic (2.1%). Based on a novel sampling technique, we demonstrate that about one third of the urine samples collected from a random sample of male climbers contained one or several drugs, suggesting frequent drug use amongst climbers ascending Mont Blanc. Our data suggest that medication primarily aims at mitigating the symptoms of altitude illnesses, rather than enhancing performance. In this hazardous environment, the relatively high prevalence of hypnotics must be highlighted, since these molecules may alter vigilance.


Asunto(s)
Ecosistema , Preparaciones Farmacéuticas/orina , Toma de Muestras de Orina/métodos , Automatización , Humanos , Masculino , Montañismo
14.
J Anal Toxicol ; 29(8): 835-7, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16374944

RESUMEN

A direct detection method for anti-doping control of recombinant human erythropoietin (rHuEPO) abuse in racehorses is proposed. This method involves screening of plasma (or serum) by an enzyme-linked immunosorbent assay specific for human EPO and confirmation in urine samples by characterization of the urinary EPO isoelectric profile. This method was tested on horses that were administered epoetin alpha (rHuEPO) and the hyper-glycosylated form of this drug (darbepoetin alpha).


Asunto(s)
Eritropoyetina/análogos & derivados , Eritropoyetina/sangre , Animales , Darbepoetina alfa , Ensayo de Inmunoadsorción Enzimática , Epoetina alfa , Eritropoyetina/orina , Caballos , Inyecciones Subcutáneas , Proteínas Recombinantes
15.
Methods Mol Biol ; 1312: 277-83, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26044010

RESUMEN

Nonspecific interactions between blotted proteins and unrelated secondary antibodies generate false positives in immunoblotting techniques. Some procedures have been developed to reduce this adsorption, but they may work in specific applications and be ineffective in others. "Double-blotting" has been developed to overcome this problem. It consists of interpolating a second blotting step between the usual probings of the blot membrane with the primary antibody and the secondary antibodies. This step, by isolating the primary antibody from the interfering proteins, guarantees the specificity of the probing with the secondary antibody. This method has been developed for the study of erythropoietin in concentrated urine since a strong nonspecific binding of biotinylated secondary antibodies to some urinary proteins is observed using classical immunoblotting protocols. However, its concept makes it usable in other applications that come up against this kind of problem. This method is expected to be especially useful for investigating proteins that are present in minute amounts in complex biological media.


Asunto(s)
Anticuerpos/inmunología , Artefactos , Eritropoyetina/análisis , Eritropoyetina/inmunología , Immunoblotting/métodos , Especificidad de Anticuerpos , Humanos
16.
Drug Test Anal ; 7(6): 531-4, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25219545

RESUMEN

As a synthetic analogue of adrenocorticotropic hormone (ACTH), tetracosactide is prohibited in sport by the World Anti-Doping Agency (WADA). An enzyme-linked immunosorbent assay (ELISA) method is proposed for detection of this drug in plasma. Since its structure corresponds to the 24 N-terminal of the 39 amino acids of the natural endogenous peptide ACTH, tetracosactide can be detected with a commercial ELISA kit for ACTH that uses antibodies, the epitopes of which are located in the 1-24 part of ACTH. However, an essential condition for detection specificity is the preliminary total clearance of endogenous ACTH in the plasma samples. This is achieved by a preparative step based on cation-exchange chromatography before ELISA. The method is specific and sensitive (LOD: 30 pg/mL) and may be used as a screening analysis in anti-doping control. The pre-analytical conditions are shown to be of the upmost importance and recommendations for blood collection (EDTA tubes), sample transport (4 °C) and plasma sample storage (-20 °C) are presented.


Asunto(s)
Cosintropina/análisis , Cosintropina/sangre , Ensayo de Inmunoadsorción Enzimática , Doping en los Deportes/prevención & control , Humanos , Límite de Detección , Sensibilidad y Especificidad
17.
J Pharm Biomed Anal ; 115: 208-13, 2015 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-26226108

RESUMEN

Chlorazanil (Ordipan, N-(4-chlorophenyl)-1,3,5-triazine-2,4-diamine) is a diuretic agent and as such prohibited in sport according to the regulations of the World Anti-Doping Agency (WADA). Despite its introduction into clinical practice in the late 1950s, the worldwide very first two adverse analytical findings were registered only in 2014, being motive for an in-depth investigation of these cases. Both individuals denied the intake of the drug; however, the athletes did declare the use of the antimalarial prophylactic agent proguanil due to temporary residences in African countries. A structural similarity between chlorazanil and proguanil is given but no direct metabolic relation has been reported in the scientific literature. Moreover, chlorazanil has not been confirmed as a drug impurity of proguanil. Proguanil however is metabolized in humans to N-(4-chlorophenyl)-biguanide, which represents a chemical precursor in the synthesis of chlorazanil. In the presence of formic acid, formaldehyde, or formic acid esters, N-(4-chlorophenyl)-biguanide converts to chlorazanil. In order to probe for potential sources of the chlorazanil detected in the doping control samples, drug formulations containing proguanil and urine samples of individuals using proguanil as antimalarial drug were subjected to liquid chromatography-high resolution/high accuracy mass spectrometry. In addition, in vitro simulations with 4-chlorophenyl-biguanide and respective reactants were conducted in urine and resulting specimens analyzed for the presence of chlorazanil. While no chlorazanil was found in drug formulations, the urine samples of 2 out of 4 proguanil users returned findings for chlorazanil at low ng/mL levels, similar to the adverse analytical findings in the doping control samples. Further, in the presence of formaldehyde, formic acid and related esters, 4-chlorophenyl-biguanide was found to produce chlorazanil in human urine, suggesting that the detection of the obsolete diuretic agent was indeed the result of artefact formation and not of the illicit use of a prohibited substance.


Asunto(s)
Antimaláricos/metabolismo , Clorobencenos/orina , Diuréticos/orina , Doping en los Deportes , Proguanil/metabolismo , Triazinas/orina , Cromatografía Liquida , Humanos , Microsomas Hepáticos/metabolismo , Espectrometría de Masas en Tándem
18.
J Immunol Methods ; 276(1-2): 223-6, 2003 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-12738375

RESUMEN

"Double-blotting" (DB) has been developed to overcome the problem of nonspecific binding of secondary antibodies in immunoblotting (IB). After it has been probed by the primary antibody, the membrane with the blotted proteins is assembled with a second blank membrane and submitted to a second blotting under acidic conditions. The primary antibody molecules are thus desorbed from their corresponding antigen and transferred onto the second membrane, whereas the antigen and the interfering proteins remain bound to the first one. The second membrane can then be probed by the secondary antibodies without the risk of nonspecific binding. This method has been developed for the study of erythropoietin (EPO) in concentrated urine since a strong nonspecific binding of biotinylated secondary antibodies to some urinary proteins is observed using classical IB protocols. However, its concept makes it usable in other applications that come up against this kind of problem.


Asunto(s)
Especificidad de Anticuerpos , Immunoblotting/métodos , Anticuerpos/inmunología , Eritropoyetina/inmunología , Eritropoyetina/orina , Focalización Isoeléctrica , Factores de Tiempo
20.
Steroids ; 86: 10-5, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24793567

RESUMEN

All systemically administered glucocorticoids (GC) are prohibited in-competition, because of the potential ergogenic effects. Although short-term GC intake has been shown to improve performance during submaximal exercise, literature on its impact during brief intense exercise appears to be very scant. The purpose of this study was to examine the ergogenic and metabolic effects of prednisone during repeated bouts of high-intensity exercise. In a double-blind randomized protocol, ten recreational male athletes followed two 1-week treatments (Cor: prednisone, 60mg/day or Pla: placebo). At the end of each treatment, they hopped on their dominant leg for 30s three times consecutively and then hopped until exhaustion, with intervals of 5min of passive recovery. Blood and saliva samples were collected at rest and 3min after each exercise bout to determine the lactate, interleukin-6, interleukin-10, TNF-alpha, DHEA and testosterone values. The absolute peak force of the dominant leg was significantly increased by Cor but only during the first 30-s hopping bout (p<0.05), whereas time to exhaustion was not significantly changed after Cor treatment vs Pla (Pla: 119.9±24.7; Cor: 123.1±29.5s). Cor intake lowered basal and end-exercise plasma interleukin-6 and saliva DHEA (p<0.01) and increased interleukin-10 (p<0.01), whereas no significant change was found in blood lactate and TNF-alpha or saliva testosterone between Pla and Cor. According to these data, short-term glucocorticoid intake did not improve endurance performance during repeated bouts of high-intensity exercise, despite the significant initial increase in absolute peak force and anti-inflammatory effect.


Asunto(s)
Metabolismo Energético/efectos de los fármacos , Ejercicio Físico/fisiología , Glucocorticoides/administración & dosificación , Glucocorticoides/farmacología , Administración Oral , Adulto , Estudios Cruzados , Método Doble Ciego , Prueba de Esfuerzo , Glucocorticoides/sangre , Voluntarios Sanos , Humanos , Masculino , Adulto Joven
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