| 1. |
- Bäcklund, Nils, et al.
(författare)
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Salivary cortisol and cortisone in diagnosis of Cushing's syndrome - a comparison of six different analytical methods
- 2023
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 61:10, s. 1780-1791
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Salivary cortisol and cortisone at late night and after dexamethasone suppression test (DST) are increasingly used for screening of Cushing's syndrome (CS). We aimed to establish reference intervals for salivary cortisol and cortisone with three liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques and for salivary cortisol with three immunoassays (IAs), and evaluate their diagnostic accuracy for CS.Methods: Salivary samples at 08:00 h, 23:00 h and 08:00 h after a 1-mg DST were collected from a reference population (n=155) and patients with CS (n=22). Sample aliquots were analyzed by three LC-MS/MS and three IA methods. After establishing reference intervals, the upper reference limit (URL) for each method was used to calculate sensitivity and specificity for CS. Diagnostic accuracy was evaluated by comparing ROC curves.Results: URLs for salivary cortisol at 23:00 h were similar for the LC-MS/MS methods (3.4-3.9 nmol/L), but varied between IAs: Roche (5.8 nmol/L), Salimetrics (4.3 nmol/L), Cisbio (21.6 nmol/L). Corresponding URLs after DST were 0.7-1.0, and 2.4, 4.0 and 5.4 nmol/L, respectively. Salivary cortisone URLs were 13.5-16.6 nmol/L at 23:00 h and 3.0-3.5 nmol/L at 08:00 h after DST. All methods had ROC AUCs =0.96.Conclusions: We present robust reference intervals for salivary cortisol and cortisone at 08:00 h, 23:00 h and 08:00 h after DST for several clinically used methods. The similarities between LC-MS/MS methods allows for direct comparison of absolute values. Diagnostic accuracy for CS was high for all salivary cortisol and cortisone LC-MS/MS methods and salivary cortisol IAs evaluated.
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| 2. |
- Chen, Yun, 1966, et al.
(författare)
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Hair glucocorticoid concentration, self-perceived stress and their associations with cardiometabolic risk markers in Swedish adolescents
- 2022
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Ingår i: Psychoneuroendocrinology. - : Elsevier BV. - 0306-4530. ; 146
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Tidskriftsartikel (refereegranskat)abstract
- Background: While hair cortisol is proposed as a biomarker for chronic stress and a possible mediator linking chronic stress and cardiovascular risk in adults, studies in adolescents are scarce. We explored the associations between self-perceived stress, hair cortisol (HairF) and cortisone (HairE), and cardiometabolic risk markers in adolescents. Further, we examined whether association between self-perceived stress and HairF may depend on the use of the coping strategies "shift-persist ". Methods: Participants were 7th grade pupils recruited to the STudy of Adolescence Resilience and Stress (STARS) and data from the baseline examinations were used. Adolescents (n = 1553, 26 % boys, Mage=13.6, SD = 0.4) completed questionnaires assessing perceived stress and coping strategies "shift-persist ", provided hair sample, and examined for cardiometabolic risk factors including waist circumference (WC), body mass index (BMI) z -score, blood pressure, and white blood cell counts (WBC). HairF and HairE were analysed using liquid chro-matography with tandem mass spectrometry. We conducted descriptive analyses (Student's t-test, Wilcoxon Signed Ranks test, Chi-square test) and linear regression analyses. Results: Perceived stress was not associated with HairF, neither had the use of coping strategies "shift-persist " any influence on this association. Both HairF and HairE were positively associated with BMI z-score (beta coefficients (8): 0.178 (p < 0.001) and 0.119 (p < 0.001) for boys; 0.123 (p < 0.001) and 0.089 (p < 0.01) for girls) and WC (8: 0.089 (p > 0.05) and 0.098 (p < 0.05) for boys; 0.103 (p < 0.01) and 0.076 (p < 0.05) for girls). Perceived stress was also positively associated with BMI z-score and WC. Perceived stress, but not HairF, remained asso-ciated with WC in boys (8 = 0.200, p < 0.001) in the models with HairF and perceived stress presented simultaneously. Modest association between HairE and WBC was found in boys (8 = 0.149, p < 0.01). Conclusions: The study supports the association between chronic stress and overweight/obesity in adolescents. Hair cortisol and self-perceived stress capture different aspects of how chronic stress is related to overweight/ obesity in adolescents.
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| 3. |
- Lustig, Florentina, 1948, et al.
(författare)
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Alternative splicing determines the binding of platelet-derived growth factor (PDGF-AA) to glycosaminoglycans.
- 1996
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 35:37, s. 12077-85
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Tidskriftsartikel (refereegranskat)abstract
- We have shown previously that the platelet-derived growth factor (PDGF) and a synthetic oligopeptide, corresponding to the basic carboxyl-terminal amino acid extension of the long PDGF-A isoform, bind to heparin. Here, we have expressed the long (rA125) and the short (rA109) variants of PDGF A-chains in Escherichia coli and produced the functional homodimers. Surface plasmon resonance analyses showed that while the dimeric rA125 bound with high affinity to low molecular weight heparin, the rA109, lacking the basic extension, did not. This strongly indicated that high affinity binding is due to the carboxyl-terminal extension. Investigations of kinetics and thermodynamics suggested an allosteric binding mechanism. Thus, dimeric rA125 contains two equivalent binding sites. Following low affinity binding of heparin to one binding site, the dimer undergoes a conformational change, increasing the affinity for heparin about 40 times. This positive cooperativity requires the basic amino acid extension in both monomers of the dimeric PDGF molecule. Thermodynamics of the reaction, showing an entropy-driven endothermic process, suggest the involvement of hydrophobic interactions in this rearrangement. Three amino acids in the basic carboxyl-terminal extension were essential for the interaction: the basic residues Arg111 and Lys116, and the polar Thr125. We also found that other glycosaminoglycan species, corresponding to those produced by human arterial smooth muscle cells, bound to dimeric rA125 and that heparan sulfate showed the highest affinity.
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