Quantification of serum androstanediol glucuronide

peer reviewe

- Cardiac biomarkers fluctuation in runners of marathons, semi-marathons and untrained runners

peer reviewe

Recertification of 25-hydroxyvitamin D standards by Isotope Pattern Deconvolution (IPD)

Vitamin D (VTD) is an important prohormone widely known since its deficiency is directly related to development of rickets in children and osteoporosis in adults. Furthermore, recent studies have demonstrated that vitamin D has also an important role in non-skeletal conditions such as autoimmune diseases, cardiovascular diseases and cancer, among others. This vitamin can be found in two main forms: vitamin D2 and vitamin D3. The metabolism of both forms of vitamin D are subjected to a first hydroxylation in the liver to form 25-hydroxyvitamin D (25(OH)D) and then to a second one in the kidney to form 1,25-dihydroxyvitamin D (1,25(OH)2D), the active form of vitamin D. Nevertheless, the measurement of 25(OH)D in serum samples is preferred test for the assessment of vitamin D status over the 1,25(OH)2D. There are two main reasons for this choice: the longer lifetime (3 weeks versus 4 h) and its higher concentration levels (ng/mL versus pg/mL)[2]. Over the last years, a dramatic rise in vitamin D testing (as 25(OH)D) has been observed, due to two main reasons: the increased number of patients with VTD deficiency and the increase of the role of VTD as a biomarker related to several diseases. In this work we propose a recertification approach for 25(OH)D2/D3 solvent standards based on Isotope Pattern Deconvolution (IPD) using NIST SRM 2972 as reference material. This approach could help to meet the requirements for external standardization criteria using in-house calibration curves

Two biomarkers for the screening of cardiac risk among runners ?

Background Heart-type fatty acid-binding protein (H-FABP) is a low molecular weight protein involved in the intracellular uptake and buffering of long chain fatty in the myocardium. Troponin T is a component of the contractile apparatus of the striated musculature. Both are early markers for acute coronary syndrome. Objective The aim of our study was to compare the results obtained with the H-FABP and the highly sensitive cardiac troponins (hsTnT) and to test their cardiospecificity in healthy runners. Design Prospective, cohort study. Setting Amateur marathon runners. Patients 23 runners (marathon) were enrolled. Interventions We drowned blood samples at three times: just before (T0), just after (T1), and three hours after the end of the race (T3). Main outcome measurements H-FABP and hs-TnT were performed according to the manufacturer's instructions. A linear regression was calculated to observe if there is any correlation between the two biomarkers. Values above the 95th percentile for H-FABP (2.5 ng/mL) and the 99th percentile for hsTnT (14 ng/L) were considered as positive. Results At T0, none of the subjects were positive for hsTnT but 35% were positive for H-FABP; at T1, 83% for hsTnT and 100% for H-FABP; at T3, 83% for hsTnT and 96% for H-FABP. At T0, the regression equation was H-FABP T0=3.9454–0.1001×hsTnT T0; at T1: H-FABP T1=51.838–1.7026×hsTnT T1; at T3: H-FABP T3=47.977–1.6193×hsTnT T3. No correlation was observed between the 2 biomarkers. Conclusion We observed a significant increase of H-FABP and hsTnT in runners. These markers are independent to each other. These values could biologically correspond to a heart ischemia. These biomarkers could be helpful for the screening of cardiac risk among runners

URINARY AND SALIVARY CORTISOL IN LIQUID CHROMATOGRAPHY–TANDEM MASS SPECTROMETRY: METHOD VALIDATION AND EXPECTED VALUES DETERMINATION

BACKGROUND: Cortisol measurement is useful in evaluation of Cushing syndrome, adrenal insufficiency, mineralocorticoid excess and congenital adrenal hyperplasia. We developed a liquid chromatography–tandem mass spectrometry (LCMS/MS) method for salivary and urinary cortisol and we determined the 95th percentile (p95) for the urinary and salivary cortisol. We compared them to the Mayo Clinic expected values. METHODS: Saliva at 8 am and 11 pm and 24h urine were obtained from 32 healthy (22 female, 34.3±9.3 yo) volunteers. We performed validation with the enoval software (Arlenda, Belgium). For the validation, we used water or urine with spiked known amounts of cortisol for the CORS and CTU respectively. For the CORS, samples were centrifuged, deuterium labelled cortisol was added as internal standard and the protein precipated by acetonitril. The supernatant was evaporated, dissolved in methanol acidified with acetic acid and analyzed by LCMS/MS. For CTU, samples were centrifuged, deuterium labelled cortisol was added as internal standard and diluted by the ammonium acetate and analyzed by LCMS/MS. At the Mayo Clinic, the expected values were 1-7.5 μg/L (7 a.m-9 a.m) and <1 μg/L (11-12 p.m) for CORS and 3.5-45 μg/24h (<18yo) for CTU. RESULTS: For the CTU, the with-in run did not exceed 3% (0.4-3%) and the between-run did not exceed 3.1% (0.4-3.1%) for 1.5-750 μg/L. The limit of quantification was 1.5 μg/L. The linearity was good between 1.5 and 750 μg/L. The recovery is 97.9±2.2% (95%CI for the mean: 92.4-101.1%). For the CORS, the with-in run and between run did not exceed 8% (1.9-8%) for 1.15-8.65 μg/L. The limit of quantification was 1.15 μg/L. The analyse presents a good linearity between 1.15 and 8.65 μg/L. The recovery is 99.9±2.9% (95%CI for the mean: 94.2-108.7%). The p95 for the CTU according to the CLSI C28-A3 was 33 μg/24h, and for the CORS was 5.42 μg/L at 8 am and 0.7 μg/L at 12 pm. CONCLUSIONS: Our developed method in liquid chromatography tandem mass spectrometry was validated for the measurement of urinary and salivary cortisol. Our findings indicate that the proposed analytical methods were suitable for routine purposes and useful in many pathological conditions.The expected values confirm these defined by the Mayo Clinic

Impact of different endurance races on the heart: the point of view of the biologist

peer reviewedObjective The aim of this study was to investigate the impact of intense exercise, represented by different endurance races, in relationship with oxidative stress and cardiac markers. In a second time, we tried to demonstrate if oxidative stress induced by physical activity is a physiological or pathological process, and to establish some issues to diagnose the risk of sudden death in athletes. Methods Four populations were compared, a control group of 16 participants “sedentary” (37 ± 4,39 years old), a group of 24 semi-marathon runners (41 years ± 8,76 years old), a group of 28 marathon runners (44,1 ± 8,37 years old) and a group of 33 ultra-trail runners (45,8 ± 8,7 years old). Three blood tests were drowned, one just before, one just after, and the last three hours after the end of the race.Different oxidative and stress and cardiac biomarkers were measured. The ultra-trail runners will be subject to an echocardiography and an ECG pre- and post-race. For statistical analysis, STATISTICA 10 software was used. We performed a non-parametric test of Kruskal-Wallis for independent sample and a Friedman ANOVA for paired samples. Results Myeloperoxydase increased during exercise, but the release is less important according to the level of training of the runners. GSH/GSSG ratio seems to remain stable during the race but it could increase during the 24 hours post-race. There is a decrease in lipidic peroxidation during exercise. But, we note an increase of creatine kinase, isoform MB, myoglobin and C-reactive protein during the race. We observe an increase of troponin T and natriuretic peptide but with a different kinetic than the kinetic obtained for a myocardial infarction. Medical imaging in ultra-trail runners present cardiac adaptations to endurance training, as left ventricular hypertrophy (LVH) and incomplete right bundle branch block (IRBBB). A decrease of systolic and diastolic volumes of the left ventricle and a decrease of longitudinal strain were observed by echocardiography at the end of the race. Conclusion Endurance races induce the income of oxidative stress objectified by different biomarkers increase, but a cell necrosis is not specially observed. In fact, the increase of the cardiac markers during endurance races but may be explained by a transient modification of myocyte permeability, with a release of pool cytosolic. These races may induce micro-muscle damages causing the appearance of an inflammatory process explaining our observations of markers of inflammation. For the medical imaging, it was observed a myocardial adaptation to training and a transient impairment of ventricular function due to dehydration

One-year follow-up of platelet-rich plasma infiltration to treat chronic proximal patellar tendinopathies

Infiltration of Platelet-Rich Plasma (PRP) may be considered as a recent therapeutic option for chronic tendinopathies. The aim of this study is to evaluate the clinical status and the return to sports activities in patients with chronic proximal patellar tendinopathies. Twenty subjects with chronic proximal patellar tendinopathy benefited from 1 infiltration of PRP coupled with a standardized eccentric rehabilitation. The follow-up (up to 1 year) was assessed by means of a Visual Anologue Scale (VAS), the International Knee Documentation Committee (IKDC) form and the Victorian Institute of Sport Assessment (VISA-P) score. Moreover, subjects had to answer an information questionnaire concerning their life and sports activities. Seventy percents of the patients reported a favourable evolution with decrease of pain, and returned to sports activities. With time, VAS dropped significantly and both IKDC and VISA-P scores improved also significantly. This study confirms that a local injection of PRP coupled with a program of eccentric rehabilitation for treating a chronic jumper’s knee, improves pain symptoms and the functionalit

Establishment of reference values for 6 six steroids in serum by LC-MS/MS

peer reviewe

Evaluation of analytical and clinical performance of the AFIAS Tn-I plus assay -a new point-of-care

peer reviewedBackground: The objective of this evaluation was to determine the analytical and clinical performance of the AFIAS point-of-care (POC) Tn-I Plus assay (Boditech Med Inc). Design and methods: Limit of detection (LOD), limit of quantification (LOQ), repeatability, reproducibility, inter-and intra-individual CV were evaluated using the CLSI guidelines. The study was also designed to estimate the 99 th percentile upper reference limit (URL) and to assess the diagnostic sensitivity and specificity. Results: The precision repeatability CVs were 6.7-8.5% and reproducibility was 7.5-7.6%. The LOD and LOQ were consistent with the manufacturer's specified values of 0.010 ng/mL and 0.030 ng/mL, respectively. The 99 th percentile URLs for males (aged 18-75 years) and females (aged 17-65 years) in serum were 0.0300 ng/mL (7.8% CV) and 0.0239 ng/mL (9.4% CV) respectively. Overall 99 th percentile URL was 0.0296 ng/mL (8.2% CV). For the overall apparently healthy population, the percentage of measurable cardiac troponin I (cTn-I) values below the 99 th percentile (i.e. 0.0296 ng/mL) and above the assay's LOD (¼ 0.010 ng/mL) was 47,68% (391/820 samples). The diagnostic sensitivity and specificity were 100% with 95% CI (97% − 100%) and 95.2% with 95% CI (93.6% − 96.5%), respectively. No significant differences were observed for the diagnosis of acute myocardial infarction (AMI) between AFIAS Tn-I plus and Abbott ARCHITECT High Sensitive Troponin-I. Conclusion: The clinical performance of AFIAS Tn-I Plus assay for AMI is comparable to the established Abbott ALINITY STAT High Sensitive Troponin-I. This assay is suitable for routine use in clinical laboratories