Determination of cortisol and associated glucocorticoids in serum and urine by an automated liquid chromatographic assay

Social regulation of leukocyte homeostasis: the role of glucocorticoid sensitivity

Recent small-scale genomics analyses suggest that physiologic regulation of pro-inflammatory gene expression by endogenous glucocorticoids may be compromised in individuals who experience chronic social isolation. The present study assessed the relationship between leukocyte distributional sensitivity to glucocorticoid regulation and subjective social isolation in a large population-based sample of older adults. Initial analyses confirmed that circulating neutrophil percentages were elevated, and circulating lymphocyte and monocyte percentages were suppressed, in direct proportion to circulating cortisol levels. However, leukocyte distributional sensitivity to endogenous glucocorticoids was abrogated in individuals reporting either occasional or frequent experiences of subjective social isolation. This finding held in both non-parametric univariate analyses and in multivariate linear models controlling for a variety of biological, social, behavioral, and psychological confounders. The present results suggest that social factors may alter immune cell sensitivity to physiologic regulation by the hypothalamic-pituitary-adrenal axis in ways that could ultimately contribute to the increased physical health risks associated with social isolation.

Perceived stress and physiological dysregulation in older adults

We use a population-based representative sample of older Taiwanese to investigate links between respondents' perceived levels of stress and a broad set of biological measures. These biomarkers were collected at a single time (2000) and reflect sympathetic nervous system (SNS)-activity, hypothalamo-pituitary-adrenal (HPA)-activity, immune function, cardiovascular function, and metabolic pathways. We model the relationship between perceived stress and (1) extreme values for each of 16 individual biological indicators; and (2) a measure of cumulative physiological dysregulation based on the full set of biomarkers. We consider two measures of perceived stress, one derived from the 2000 interview and the second based on data from three interviews (1996-2000). Age and sex-adjusted models reveal significant associations between measures of perceived stress and extreme values of cortisol, triglycerides, interleukin-6 (IL-6), dehydroepiandrosterone sulphate (DHEAS) and fasting glucose. Examined individually, numerous biomarkers, including those pertaining to blood pressure and obesity, are not significantly related to perceived stress. Jointly, however, the measure of cumulative physiological dysregulation is associated with both the level of perceived stress at a given time and to a longitudinal measure of perceived stress. Some results suggest that the relationship between level of perceived stress and physiological response is stronger for women than men.

High-performance liquid chromatographic analysis of corticosteroids

This review presents recent developments in high-performance liquid chromatographic (HPLC) analysis of corticosteroids for the determination of clinically important steroids in biological specimens. Various sample preparation techniques are described.

Column-switching high-performance liquid chromatographic system with a laser-induced fluorimetric detector for direct, automated assay of salivary cortisol

In order to measure human stress, an easy and rapid, fully automated method for the determination of cortisol in saliva has been developed, using column-switching high-performance liquid chromatography with laser-induced fluorescence detection, which involves post-column labeling with sulfuric acid. The developed system requires only 0.1 ml of saliva, and a simple pretreatment consisting of dilution and filtration is sufficient. The column-switching system consisted of a Polymer-Coated Mixed-Functional silica (PCMF) column for deproteinization, and a CN column for frontal concentration and separation. An ODS column in place of the CN provided a better separation, but required a post-column make-up of water for safe reaction. Detection limit of cortisol was 8 fmol (signal-to-noise ratio = 3), which is adequate for routine determination of normal levels of cortisol (1-20 pmol/ml). The analysis time was about 40 min and reproducibility was excellent with an R.S.D. of less than 5%.

Simple and specific reversed-phase liquid chromatographic method with diode-array detection for simultaneous determination of serum hydroxychloroquine, chloroquine and some corticosteroids

This paper describes a simple, specific, and sensitive high-performance liquid chromatographic (HPLC) method using ion-pair reversed-phase chromatography with photodiode-array detection for the simultaneous determination of hydroxychloroquine (HCQ) and chloroquine (CQ) in serum samples from rheumatoid arthritis patients receiving either HCQ sulphate or CQ diphosphate. The assay is also applicable to the simultaneous determination of corticosteroids. The method consisted of two diethyl ether extractions of 1.0 ml of serum, to which two internal standards (2,3-diaminonaphthalene and 18-hydroxy-11-deoxycorticosterone) and 1.0 ml of 0.25 M sodium hydroxide had been added. After the organic phase was evaporated to dryness at 30-40 degrees C under a stream of nitrogen, the extract was reconstituted with a 1:1 mixture of 0.1 M perchloric acid and methanol, an aliquot of which was injected on to the system. Peak-height ratios at different wavelengths (A245/343, A245/256, A245/265 and A245/275) were utilized as a method of assessing peak homogeneity. Some anti-inflammatory drugs which may be used for rheumatic disorders were shown not to interfere with the assay. The method provides selectivity by using diode-array detection at several wavelengths. The use of two internal standards not only compensates for losses during the sample manipulation but also prevents erroneous results in case of interference.