A time-resolved fluorescence immunoassay for the measurement of testosterone in saliva: Monitoring of testosterone replacement therapy with testosterone buciclate

Monitoring of testosterone replacement therapy requires a reliable method for testosterone measurement. Determination of salivary testosterone, which reflects the hormone's biologically active plasma fraction, is a superior technique for this purpose. The aim of the present study was to establish a new sensitive time-resolved fluorescence immunoassay for the accurate measurement of testosterone levels in saliva and to validate it by monitoring testosterone replacement therapy in eight hypogonadal men. A clinical phase I- study with the new ester testosterone buciclate was performed to search for new testosterone preparations to produce constant serum levels in the therapy of male hypogonadism. After two control examinations eight male patients with primary hypogonadism were randomly assigned to two treatment groups (n = 2x4) and given single doses of either 200 mg (group I) or 600 mg (group II) testosterone buciclate intramuscularly. Saliva and blood samples were obtained 1, 2, 3, 5 and 7 days post injection and then weekly for three months. The time-resolved fluorescence immunoassay for salivary testosterone shows a detection limit of 16 pmol/l, an intra-assay CV of 8.9% (at a testosterone concentration of 302 pmol/l), an inter-assay CV of 8.7% (at a testosterone concentration of 305 pmol/l) and a good correlation with an established radioimmunsassay of r = 0.89. The sample volume required by this method is only 180 mu l for extraction and duplicate determination. The assay procedure requires no more than three hours. In group I (200 mg) testosterone did not increase to normal levels either in saliva or in serum. However, in group II, androgen levels increased significantly and were maintained in the normal range for up to 12 weeks with maximal salivary testosterone levels of 303 +/- 18 pmol/l (mean+/-SE) and maximal testosterone levels of 13.1 +/- 0.9 nmol/l (mean+/-SE) in serum in study week 6 and 7. The time-resolved fluorescence immunoassay for salivary testosterone provides a useful tool for monitoring androgen status in men and women and is well suited for the follow-up of testosterone replacement therapy on an outpatient basis. The long-acting ester testosterone buciclate is a promising agent for substitution therapy of male hypogonadism and in combination with testosterone monitoring in saliva offers an interesting new perspective for male contraception

FI on-line chemiluminescence reaction for determination of MCPA in water samples

This paper reports an economic, simple, and rapid FI-CL method for the determination of MCPA. This method requires simple instrumentation and it is fast enough to be used in routine analyses. A chemiluminescence signal is generated by reaction between photodegraded MCPA and ferricyanide solution in alkaline medium. All physical and chemical parameters in the flow injection chemiluminescence system were optimized in the experimental setting. To eliminate interference, a solid-phase extraction stage with SDB-1 cartridges and ethanol elution is applied. The signal-MCPA concentration relation is linear in concentration intervals between 0.0015 and 0.6 ¿g¿mL -1. The calibration lines are statistically similar in different working conditions: standards with ethanol without extraction and standards with ethanol and extraction, allowing standards to be excluded from the extraction step, which simplifies the process. The detection limit (DL) is 0.5 ng¿mL -1, which is the same order as the maximum limit established in legislation regarding pesticide limits in water destined for human consumption. A DL of 0.13 ng¿mL -1 can be reached if a sample of 100 mL is preconcentrated. The interday variance coefficient is 3% and the sample throughput is 90 h -1. The water analysis method is efficient with relative error percentages lower than 5% with respect to the added concentration. © 2011 Springer-Verlag.Authors acknowledge to the "Ministerio de Educacion y Ciencia" of Spain and FEDER funds for financial support (Project CTM2006-11991)Torres Cartas, S.; Gómez Benito, C.; Meseguer-Lloret, S. (2012). FI on-line chemiluminescence reaction for determination of MCPA in water samples. Analytical and Bioanalytical Chemistry. 402:1289-1296. https://doi.org/10.1007/s00216-011-5567-1S12891296402Navarro JS (2008) Utilización de plaguicidas en las asociaciones de tratamientos integrados en agricultura en la región de Murcia. Consejería de Sanidad Región de MurciaBarceló D, Hennion MC (1997) Trace determination of pesticide and their degradation products in water. Elsevier, AmsterdamKöck M, Farré M, Martínez E, Gajda-Schrantz K, Ginebreda A, Navarro A, López de Alda M, Barceló D (2010) J Hydrol 383(1–2):73–82Woudneh MB, Sekela M, Tuominen T, Gledhill M (2007) J Chromatogr A 1139(1):121–129Laganà A, Bacaloni A, De-Leva I, Faberi A, Fago G, Marino A (2002) Anal Chim Acta 462:187–198Comoretto L, Arfib B, Chiron S (2007) Sci Total Environ 380(1–3):124–132Kuster M, de Alda MJL, Barata C, Raldá D, Barceló D (2008) Talanta 75(2):390–401Kuster M, de Alda MJL, Hernando MD, Petrovic M, Martín-Alonso J, Barceló D (2008) J Hydrol 358(1–2):112–123Gervais G, Brosillon S, Laplanche A, Helen C (2008) J Chromatogr A 1202(2):163–172Housari F, Höhener P, Chiron S (2011) Sci Total Environ 409(3):582–587Delhomme O, Raeppel C, Briand O, Millet M (2011) Anal Bioanal Chem 399:1325–1334Royal decree 140/2003, 7th of February that establishes the health criteria for the water quality for human consumption. (BOE 21 February 2003)von-der-Ohe PC, Dulio V, Slobodnik J, de-Deckere E, Köhne R, Ebert RU, Ginebreda A, de-Cooman de-Cooman W, Schüürmann G, Brack W (2011) Sci Total Environ 409(11):2064–2077Horwitz W (ed) (2000) Official methods of analysis of AOAC International, 17th edn. AOAC International, GaithersburgMoret S, Sánchez JM, Salvadó V, Hidalgo M (2005) J Chromatogr A 1099(1–2):55–63Tran ATK, Hyne RV, Doble P (2007) Chemosphere 67(5):944–953Long F, Shi HC, He M, Zhu AN (2008) Biosens Bioelectron 23:1361–1366Meulenberg EP, Stoks PG (1995) Anal Chim Acta 311:407–413Chuang JC, Van Emon JM, Durnford J, Thomas K (2005) Talanta 67:658–666Boro RC, Kaushal J, Nangia Y, Wangoo N, Bhashi A, Suri CR (2011) Analyst 136(10):2125–2130Eremin SA, Laassis P, Aaron JJ (1996) Talanta 43:295–301Almansa-López EM, García-Campaña AM, Aaron JJ, Cuadros-Rodriguez L (2003) Talanta 60:355–367García LF, Eremin S, Aaron JJ (1996) Anal Lett 29(8):1447–1461García-Campaña AM, Aaron JJ, Bosque-Sendra JM (2002) Luminescence 17:285–287Lara FJ, García-Campaña AM, Aaron JJ (2010) Anal Chim Acta 679:17–30López-Paz J, Catalá-Icardo M (2011) Anal Lett 44(1–3):146–175Mbaye M, Gaye-Seye M, Aaron JJ, Coly A, Tine A (2011) Anal Bioanal Chem 400(2):403–410López-Paz JL, Catalá-Icardo M, Antón-Garrido B (2009) Anal Bioanal Chem 394:1073–1079López-Paz J, Catalá-Icardo M (2008) Anal Chim Acta 625(2):173–179Chen X, Lin Z, Cai Z, Chen X, Wang X (2008) Talanta 76(5):1083–1087Meseguer-Lloret S, Torres-Cartas S, Gómez-Benito M (2010) Anal Bioanal Chem 398:3175–3182Catalá-Icardo M, Martínez-Calatayud J (2008) Crit Rev Anal Chem 38(2):118–13

Is Cortisol Excretion Independent of Menstrual Cycle Day? A Longitudinal Evaluation of First Morning Urinary Specimens

Background Cortisol is frequently used as a marker of physiologic stress levels. Using cortisol for that purpose, however, requires a thorough understanding of its normal longitudinal variability. The current understanding of longitudinal variability of basal cortisol secretion in women is very limited. It is often assumed, for example, that basal cortisol profiles do not vary across the menstrual cycle. This is a critical assumption: if cortisol were to follow a time dependent pattern during the menstrual cycle, then ignoring this cyclic variation could lead to erroneous imputation of physiologic stress. Yet, the assumption that basal cortisol levels are stable across the menstrual cycle rests on partial and contradictory evidence. Here we conduct a thorough test of that assumption using data collected for up to a year from 25 women living in rural Guatemala. Methodology We apply a linear mixed model to describe longitudinal first morning urinary cortisol profiles, accounting for differences in both mean and standard deviation of cortisol among women. To that aim we evaluate the fit of two alternative models. The first model assumes that cortisol does not vary with menstrual cycle day. The second assumes that cortisol mean varies across the menstrual cycle. Menstrual cycles are aligned on ovulation day (day 0). Follicular days are assigned negative numbers and luteal days positive numbers. When we compared Models 1 and 2 restricting our analysis to days between −14 (follicular) and day 14 (luteal) then day of the menstrual cycle did not emerge as a predictor of urinary cortisol levels (p-value >0.05). Yet, when we extended our analyses beyond that central 28-day-period then day of the menstrual cycle become a statistically significant predictor of cortisol levels. Significance The observed trend suggests that studies including cycling women should account for day dependent variation in cortisol in cycles with long follicular and luteal phases