Cortisol response to critical illness:Effect of intensive insulin therapy

Context: Both excessive and insufficient activation of the hypothalamic-pituitary-adrenal axis in response to critical illness is associated with increased mortality. Objective: The objective of the study was to study the effect of intensive insulin therapy, recently shown to reduce mortality and morbidity of critically ill patients, on the cortisol response to critical illness. Design: This was a preplanned subanalysis of a large randomized, controlled study measuring serum total cortisol, cortisol-binding globulin, and albumin and calculating free cortisol levels. Setting: The study was conducted at a university hospital surgical intensive care unit. Patients: Four hundred fifty-one critically ill patients dependent on intensive care for more than 5 d and 45 control subjects matched for gender, age, height, and weight participated in this study. Intervention: The intervention was strict blood glucose control to normoglycemia with insulin. Results: Total and calculated free cortisol levels were equally elevated upon admission in both patient groups and thereafter were lower in intensive insulin-treated patients. Lower cortisol levels statistically related to the outcome benefit of intensive insulin therapy. Cortisol-binding globulin levels and structure were affected by critical illness but not insulin therapy, and neither were albumin levels. Administration of hydrocortisone in so-called replacement dose resulted in severalfold higher total and free cortisol levels, indicating that reevaluation of the doses used is warranted. Conclusions: Lower serum cortisol levels in critically ill patients receiving intensive insulin therapy statistically related to improved outcome with this intervention. The lower cortisol levels were not related to altered cortisol-binding capacity.</p

Cortisol response to critical illness:Effect of intensive insulin therapy

Context: Both excessive and insufficient activation of the hypothalamic-pituitary-adrenal axis in response to critical illness is associated with increased mortality. Objective: The objective of the study was to study the effect of intensive insulin therapy, recently shown to reduce mortality and morbidity of critically ill patients, on the cortisol response to critical illness. Design: This was a preplanned subanalysis of a large randomized, controlled study measuring serum total cortisol, cortisol-binding globulin, and albumin and calculating free cortisol levels. Setting: The study was conducted at a university hospital surgical intensive care unit. Patients: Four hundred fifty-one critically ill patients dependent on intensive care for more than 5 d and 45 control subjects matched for gender, age, height, and weight participated in this study. Intervention: The intervention was strict blood glucose control to normoglycemia with insulin. Results: Total and calculated free cortisol levels were equally elevated upon admission in both patient groups and thereafter were lower in intensive insulin-treated patients. Lower cortisol levels statistically related to the outcome benefit of intensive insulin therapy. Cortisol-binding globulin levels and structure were affected by critical illness but not insulin therapy, and neither were albumin levels. Administration of hydrocortisone in so-called replacement dose resulted in severalfold higher total and free cortisol levels, indicating that reevaluation of the doses used is warranted. Conclusions: Lower serum cortisol levels in critically ill patients receiving intensive insulin therapy statistically related to improved outcome with this intervention. The lower cortisol levels were not related to altered cortisol-binding capacity.</p

Active vitamin D (1,25-dihydroxyvitamin D) and bone health in middle-aged and elderly men: the European male aging study (EMAS)

&lt;p&gt;Context: There is little information on the potential impact of serum 1,25-dihydroxyvitamin D [1,25(OH)2D] on bone health including turnover.&lt;/p&gt; &lt;p&gt;Objective: The objective of the study was to determine the influence of 1,25(OH)2D and 25-hydroxyvitamin D [25(OH)D] on bone health in middle-aged and older European men.&lt;/p&gt; &lt;p&gt;Design, Setting, and Participants: Men aged 40–79 years were recruited from population registers in 8 European centers. Subjects completed questionnaires that included questions concerning lifestyle and were invited to attend for quantitative ultrasound (QUS) of the heel, assessment of height and weight, and a fasting blood sample from which 1,25(OH)2D, 25(OH)D, and PTH were measured. 1,25(OH)2D was measured using liquid chromatography tandem mass spectrometry. Bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (β-cTX) were also measured. Dual-energy x-ray absorptiometry (DXA) of the hip and lumbar spine was performed in 2 centers.&lt;/p&gt; &lt;p&gt;Main Outcome Measure(s): QUS of the heel, bone markers P1NP and β-cTX, and DXA of the hip and lumbar spine were measured.&lt;/p&gt; &lt;p&gt;Results: A total of 2783 men, mean age 60.0 years (SD 11.0) were included in the analysis. After adjustment for age and center, 1,25(OH)2D was positively associated with 25(OH)D but not with PTH. 25(OH)D was negatively associated with PTH. After adjustment for age, center, height, weight, lifestyle factors, and season, 1,25(OH)2D was associated negatively with QUS and DXA parameters and associated positively with β-cTX. 1,25(OH)2D was not correlated with P1NP. 25(OH)D was positively associated with the QUS and DXA parameters but not related to either bone turnover marker. Subjects with both high 1,25(OH)2D (upper tertile) and low 25(OH)D (lower tertile) had the lowest QUS and DXA parameters and the highest β-cTX levels.&lt;/p&gt; &lt;p&gt;Conclusions: Serum 1,25(OH)2D is associated with higher bone turnover and poorer bone health despite being positively related to 25(OH)D. A combination of high 1,25(OH)2D and low 25(OH)D is associated with the poorest bone health.&lt;/p&gt

Active vitamin D (1,25-dihydroxyvitamin D) and bone health in middle-aged and elderly men: the European male aging study (EMAS)

&lt;p&gt;Context: There is little information on the potential impact of serum 1,25-dihydroxyvitamin D [1,25(OH)2D] on bone health including turnover.&lt;/p&gt; &lt;p&gt;Objective: The objective of the study was to determine the influence of 1,25(OH)2D and 25-hydroxyvitamin D [25(OH)D] on bone health in middle-aged and older European men.&lt;/p&gt; &lt;p&gt;Design, Setting, and Participants: Men aged 40–79 years were recruited from population registers in 8 European centers. Subjects completed questionnaires that included questions concerning lifestyle and were invited to attend for quantitative ultrasound (QUS) of the heel, assessment of height and weight, and a fasting blood sample from which 1,25(OH)2D, 25(OH)D, and PTH were measured. 1,25(OH)2D was measured using liquid chromatography tandem mass spectrometry. Bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (β-cTX) were also measured. Dual-energy x-ray absorptiometry (DXA) of the hip and lumbar spine was performed in 2 centers.&lt;/p&gt; &lt;p&gt;Main Outcome Measure(s): QUS of the heel, bone markers P1NP and β-cTX, and DXA of the hip and lumbar spine were measured.&lt;/p&gt; &lt;p&gt;Results: A total of 2783 men, mean age 60.0 years (SD 11.0) were included in the analysis. After adjustment for age and center, 1,25(OH)2D was positively associated with 25(OH)D but not with PTH. 25(OH)D was negatively associated with PTH. After adjustment for age, center, height, weight, lifestyle factors, and season, 1,25(OH)2D was associated negatively with QUS and DXA parameters and associated positively with β-cTX. 1,25(OH)2D was not correlated with P1NP. 25(OH)D was positively associated with the QUS and DXA parameters but not related to either bone turnover marker. Subjects with both high 1,25(OH)2D (upper tertile) and low 25(OH)D (lower tertile) had the lowest QUS and DXA parameters and the highest β-cTX levels.&lt;/p&gt; &lt;p&gt;Conclusions: Serum 1,25(OH)2D is associated with higher bone turnover and poorer bone health despite being positively related to 25(OH)D. A combination of high 1,25(OH)2D and low 25(OH)D is associated with the poorest bone health.&lt;/p&gt

Letter to the Editor: 25-Hydroxyvitamin D Does Not Interfere With Liquid Chromatography Tandem Mass Spectrometry Assays for 1,25-Dihydroxyvitamin D

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Canonical and non-canonical EcfG sigma factors control the general stress response in Rhizobium etli

A core component of the α-proteobacterial general stress response (GSR) is the extracytoplasmic function (ECF) sigma factor EcfG, exclusively present in this taxonomic class. Half of the completed α-proteobacterial genome sequences contain two or more copies of genes encoding σ(EcfG) -like sigma factors, with the primary copy typically located adjacent to genes coding for a cognate anti-sigma factor (NepR) and two-component response regulator (PhyR). So far, the widespread occurrence of additional, non-canonical σ(EcfG) copies has not satisfactorily been explained. This study explores the hierarchical relation between Rhizobium etli σ(EcfG1) and σ(EcfG2) , canonical and non-canonical σ(EcfG) proteins, respectively. Contrary to reports in other species, we find that σ(EcfG1) and σ(EcfG2) act in parallel, as nodes of a complex regulatory network, rather than in series, as elements of a linear regulatory cascade. We demonstrate that both sigma factors control unique yet also shared target genes, corroborating phenotypic evidence. σ(EcfG1) drives expression of rpoH2, explaining the increased heat sensitivity of an ecfG1 mutant, while katG is under control of σ(EcfG2) , accounting for reduced oxidative stress resistance of an ecfG2 mutant. We also identify non-coding RNA genes as novel σ(EcfG) targets. We propose a modified model for GSR regulation in R. etli, in which σ(EcfG1) and σ(EcfG2) function largely independently. Based on a phylogenetic analysis and considering the prevalence of α-proteobacterial genomes with multiple σ(EcfG) copies, this model may also be applicable to numerous other species.status: publishe

Possibilities and limitations of signal summing for an immunosuppressant LC-MS/MS method

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the method of choice for quantifying small molecules in research and clinical setting. Although there is a large toolkit to increase quantification levels for LC-MS/MS, these techniques are sometimes insufficient to attain the needed limits of quantification (LOQs) or the method becomes too impractical for routine use. We examined the possibilities and limitations of signal summing, an under-utilized, easy-to-apply practice to increase LOQs for an immunosuppressant LC-MS/MS method. The limits of signal summing for everolimus were tested by running samples of everolimus at three concentrations in triplicate programming, increasing amounts of identical transitions in a constant cycle time up to the maximum number the software permitted to sum. The increase in peak area and the signal-to-noise ratio were determined. The effect on imprecision of peak areas and response ratios was evaluated by injection of a low concentration of everolimus tenfold using respectively one and five identical transitions, retaining an identical ion counting time. We compared the imprecision, LOQ, and recovery for our routine everolimus method (using one transition for everolimus and one for d3-everolimus) and an adapted method summing three identical transitions for everolimus (and one for d3-everolimus). The increase in signal was close to the theoretically expected one with a larger experimental spread for everolimus once more than five transitions were used. There was no clear beneficial effect of summing on imprecision. The adapted everolimus method showed a lower LOQ, but comparable imprecision and recovery as the routine method. Quantification levels can be improved by signal summing. No clear effect on imprecision was observed.status: publishe

Need for Estradiol Assays With a Lower Functional Sensitivity in Clinical Studies Examining Postmenopausal Women Treated With Aromatase Inhibitors

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Sensitive routine liquid chromatography-tandem mass spectrometry method for serum estradiol and estrone without derivatization

The need for a routinely applicable assay to measure low estradiol levels in adult men, postmenopausal women, and young adolescents was recently discussed in an Endocrine Society position statement. Our aim was to develop a sensitive liquid chromatography-tandem mass spectrometry method for estradiol and estrone in human serum without the need for derivatization or extended extraction protocols. After protein precipitation of serum with a mixture of methanol/acetonitrile (85/15) (v/v) containing isotopic internal standards (17β-estradiol-16,16,17-d 3 and estrone-2,3,4-(13)C), we quantified estradiol and estrone by two-dimensional liquid chromatography-tandem mass spectrometry with electrospray ionization in the negative mode monitoring 5 × 271.20→145.00 (17β-estradiol) and 269.20→145.00 (estrone). Sensitivity was increased by using fluoride and summation of 5 identical transitions for estradiol. Our method was analytically validated, compared against direct immunoassays using serum of 25 adult men, and clinically tested by measuring samples of 3 men at baseline and after chemical castration, 30 postmenopausal women and 15 patients receiving aromatase inhibitors. Total imprecision was below 20 % for the low quality controls. Limit of quantification was 1.3 ng/L (4.8 pmol/L) for estradiol and 1.2 ng/L (4.4 pmol/L) for estrone. Estradiol in Certified Reference Material BCR-576 was within specified uncertainty limits. No significant ion suppression or interference was observed. Our method showed modest correlation with direct immunoassay for estradiol (r (2) = 0.64) but no correlation for estrone (r (2) = 0.12). Patient sample results were within expected ranges. In conclusion, we developed a routinely applicable liquid chromatography-tandem mass spectrometry method for estradiol and estrone measurement which is sensitive enough for use in men, postmenopausal women, and young adolescents.status: publishe