A complete screening and confirmation analytical method for the direct determination of six endogenous (cortisol, cortisone, deoxycorticosterone, tetrahydrocortisol, tetrahydrocortisone, tetrahydro-S) and 17 synthetic (amcinonide, betamethasone, desoximethasone, dexamethasone, fludrocortisone, flumethasone, flunisolide, flucinolone acetonide, flucinonide, fluprednisolone, flurandrenolide, fluorometholone, 6-methylprednisolone, prednisolone, prednisone, triamcinolone, triamcinolone acetonide) glucocorticoids in human urine by gas chromatography with mass spectrometric detection (GC-MS) is presented.The analytical technique comprises a pre-treatment procedure and the instrumental analysis of the trimethylsilyl (TMS) derivatives, performed by GC-MS (quadrupole) with electron impact (EI) ionization. The derivatization yields obtained by two different derivatizing mixtures, namely N-methyl-N(trimethylsilyl)trifluoroacetamide (MTSFA):NH4I:dithioerythritol (DTE) 1000:2:4 (usually indicated as TMSiodine); and N-trimethylsilylimidazole (TMSim):N,O-bis(trimethylsilyl)acetamide (BSA):trimethylchlorosilane (TMCS) 3:3:2, both under direct thermal heating and with microwave (MW) irradiation, were evaluated, also as a function of the temperature, of the MW power and of the incubation time.The highest yields of the derivatization process were obtained, for most of the compounds here considered, by a two-step procedure: a microwave-assisted derivatization stage (40 min in a microwave oven at 900 W emitted power), followed by a traditional heat transfer derivatization (1.5 h in a thermostated bath at 70 °C) with the derivatization mixture TMSim:BSA:TMCS 3:3:2. In these operating conditions, diagnostic EI-MS spectra of all considered glucocorticoids were obtained. Limits of detection (LOD) of synthetic glucocorticoids in urine ranged from 3 to 25 μg/l. The effectiveness of the method for the determination of glucocorticoids in urine was evaluated on spiked urine samples and on real samples obtained from patients under pharmacological treatment with synthetic glucocorticoids.Apart from the clinical monitoring of glucocorticoids in urine, the method can be applied as a complete screening + confirmation analytical protocol in antidoping tests for the detection of illicit administration of glucocorticoids by the athletes. 相似文献
This paper presents a gas chromatography-mass spectrometry (GC-MS) study carried out on human urine to verify whether the administration of glucocorticoids can affect the urinary steroid profile, and especially the levels of endogenous glucocorticoids, androgens and their main metabolites.Betamethasone and beclomethasone, administered either systemically (per os or i.m.) or locally (by inhalation) have been studied. The determination of the urinary levels of endogenous glucocorticoids and androgens was carried out by GC-MS in electron impact ionization mode. Data were evaluated taking into account the baseline individual variability, and compared with values obtained on a control group.Detectable differences were recorded in the steroids metabolites excretion profiles between men and women. The circadian variability of the steroid profile was the same for both sexes, showing a maximum during the morning hours. After systemic treatment with synthetic glucocorticoids, the relative urinary concentrations of corticosteroids, androgens and of their metabolites were significantly altered, recording a transient decrease of the concentration of cortisol and tetrahydrocortisol and a parallel, although less pronounced, increase of the concentration of testosterone, epitestosterone and related androgenic steroids; while no effects were recorded if the administration was by inhalation. 相似文献
Bone histomorphometry or quantitative histology consists of counting or measuring tissue components: cells, extracellular constituents and microarchitecture. Bone histomorphometry is the only method that allows the measurement of mineralization rate and the study of bone formation at three levels: cell, remodeling unit and tissue levels. It is a useful tool to explain the pathogenesis and cellular mechanisms of different metabolic bone diseases such as glucocorticoid-induced osteoporosis (GIO).
Glucocorticoids (GC) affect calcium and bone metabolism at every level, but the main effect is the osteoblastic dysfunction.
Concerning the bone formation, some histomorphometric studies have shown a depressed osteoblastic activity at a cell, bone remodeling unit, and tissue levels. In addition, there is evidence of a shortening of the period in which the osteoblasts work actively forming the bone matrix. This latter effect seems to occur after high cumulative doses of GC. With regard to the resorption, the results are still debated, but histomorphometric parameters seem to be increased in the majority of studies, at least in the first period of the GC treatment. From a structural point of view, GC seem to induce a thinning of the trabeculae without their perforation, which occurs only after high cumulative doses. Antiresorptive treatments, such as bisphosphonates, are able to counteract the negative effects of GC on bone. In particular, along with their active working period, they prolong the lifespan of osteoblasts and osteocytes. In addition, the antiresorptive treatments seem to extend the time for secondary mineralization through a reduction of the Activation Frequency. The latter is an intriguing mechanism of bisphosphonates in GIO that needs further ad hoc investigations. 相似文献
We have developed a synergic microextraction procedure based on ionic liquid for the pre‐concentration and determination of glucocorticoids in water samples. Using nonionic surfactant Triton X‐100 (TX‐100) as synergic reagent, 1‐butyl‐3‐methylimidazolium hexa‐fluorophosphate accomplished extraction rapidly without heating in water bath. One key property of ionic liquids that highlights their potential is their wide liquid temperature range. The improved extraction was named as ionic liquid supported vortex‐assisted synergic microextraction. Compared with the traditional liquid–liquid extraction and cloud point extraction, ionic liquid supported vortex‐assisted synergic microextraction was accomplished in 8 min with considerably high recovery. The proposed method greatly improved the sensitivity of HPLC for the determination of glucocorticoids. The results obtained indicated a good linearity with the correlation coefficient of 0.997 over the range of 0.6–300 ng/mL and high sensitivity with LODs of 4.11, 9.19, and 7.50 ng/mL for hydrocortisone butyrate, beclomethasone dipropionate, and nandrolone phenylpropionate, respectively. The RSD of the method was 1.57–1.81% (n = 6) with enrichment factor of 99.85, and good recovery (≥97.24%). The method was successfully applied to the determination of glucocorticoids in mineral water, water of Dianchi lake, and tap water samples. 相似文献
Summary A method has been developed to measure simultaneously in human plasma the mineralocorticoids and glucocorticoids involved
in mineralocorticoid excess.
Briefly: plasma extracts were chromatographied in a fully-automated procedure on a lichrospher-diol column using a hexane:
isoproanol: trithylamine gradient. Eluates were collected on a preprogrammed fraction collector. Final quantification was
achieved by RIA on the selected fractions.
This procedure allowed: 1) the separation of each measured steroid from plasma contaminants; 2) precise collection; 3) quantification
of mineralocorticoids with a precision and sensitivity equivalent to that of direct methods; and 4) improved specificity. 相似文献