Assessment of the Androstenedione Assay on a Roche Analytical Platform and Comparison with Different Methods.

BACKGROUND: D4-androstenedione (D4ASD) is an intermediate hormone of androgen biosynthesis by the gonads and the adrenal glands. The interest in D4ASD concentration assessment resides in diagnostics of androgenic hyperproduction pathologies. Currently, many D4ASD quantification methods are available on the market including immunological methods that remain problematic due to the possible cross-reactivity with endogenous or exogenous steroids. METHODS: Recently Roche® launched a new fully automated instrument for the measurement of D4ASD concentration. In this paper, the criteria of analytical performance (repeatability and intermediate precision) of the D4ASD Roche® assay were assessed and compared with 2 different methods including a radioimmunoassay (RIA) as well as a liquid chromatography tandem mass spectrometry (LC-MS/MS) method. RESULTS: Repeatability and intermediate precision of the D4ASD Roche® were acceptable according to the prede-fined RICOS standard (CV ≤ 7.9%) and the assay showed a good correlation with other assays considering the 95% CI obtained for the slope and the y-intercept. CONCLUSIONS: This method demonstrates acceptable criteria of analytical performance with an intermediate imprecision and a trueness within the fixed acceptance limits.

The free cortisol calculated: correlation with the free cortisol concentrations measured with liquid chromatography-tandem mass spectrometry after equilibrium dialysis and establishment of reference intervals.

BACKGROUND: Changes in cortisol binding globulin (CBG) impact the total serum cortisol concentration and affect the accurate assessment of adrenal function. Free biologically cortisol can be calculated using different equations or directly measured after complicated procedures. METHODS: The free cortisol index (FCI) obtained using the Bonte formula as well as the free cortisol concentration calculated (Coolens equation) were first estimated for 45 healthy workers. The CBG level was determined by a competitive radioimmunoassay and the total cortisol concentration, was measured with an electrochemiluminescent assay. The correlations between FCI, the free cortisol concentrations calculated and the free cortisol levels measured with liquid chromatography-tandem mass spectrometry after equilibrium dialysis were studied for those 45 samples. Reference limits were established on 158 healthy hospital workers and patients with serum samples collected between 7:30 am and 10 am. RESULTS: The FCI as well as the free cortisol concentrations calculated obtained for the 45 samples correlated significantly with the free cortisol levels measured. Although the cortisol and CBG levels were statistically higher in women using contraceptives compared with women not taking them as well as men, the calculated FCI and free cortisol concentrations did not differ between these groups. The medians (P2.5-P97.5) obtained for the 158 healthy workers were respectively 26.4% (12.3-51.6%) and 10.6 nmol/L (4.3-26.7 nmol/L). CONCLUSIONS: This study highlighted a significant correlation between the FCI, the free cortisol concentrations calculated and the free cortisol levels measured with LC-MS/MS, it has also allowed the establishment of reference intervals for calculated FCI and free cortisol.

Short halt in vaping modifies cardiorespiratory parameters and urine metabolome: a randomized trial.

Propylene glycol and glycerol are e-cigarette constituents that facilitate liquid vaporization and nicotine transport. As these small hydrophilic molecules quickly cross the lung epithelium, we hypothesized that short-term cessation of vaping in regular users would completely clear aerosol deposit from the lungs and reverse vaping-induced cardiorespiratory toxicity. We aimed to assess the acute effects of vaping and their reversibility on biological/clinical cardiorespiratory parameters [serum/urine pneumoproteins, hemodynamic parameters, lung-function test and diffusing capacities, transcutaneous gas tensions (primary outcome), and skin microcirculatory blood flow]. Regular e-cigarette users were enrolled in this randomized, investigator-blinded, three-period crossover study. The periods consisted of nicotine-vaping (nicotine-session), nicotine-free vaping (nicotine-free-session), and complete cessation of vaping (stop-session), all maintained for 5 days before the session began. Multiparametric metabolomic analyses were used to verify subjects' protocol compliance. Biological/clinical cardiorespiratory parameters were assessed at the beginning of each session (baseline) and after acute vaping exposure. Compared with the nicotine- and nicotine-free-sessions, a specific metabolomic signature characterized the stop-session. Baseline serum club cell protein-16 was higher during the stop-session than the other sessions (P < 0.01), and heart rate was higher in the nicotine-session (P < 0.001). Compared with acute sham-vaping in the stop-session, acute nicotine-vaping (nicotine-session) and acute nicotine-free vaping (nicotine-free-session) slightly decreased skin oxygen tension (P < 0.05). In regular e-cigarette-users, short-term vaping cessation seemed to shift baseline urine metabolome and increased serum club cell protein-16 concentration, suggesting a decrease in lung inflammation. Additionally, acute vaping with and without nicotine decreased slightly transcutaneous oxygen tension, likely as a result of lung gas exchanges disturbances.

Fourth generation e-cigarette vaping induces transient lung inflammation and gas exchange disturbances: results from two randomized clinical trials.

When heated by an electronic cigarette, propylene glycol and glycerol produce a nicotine-carrying-aerosol. This hygroscopic/hyperosmolar aerosol can deposit deep within the lung. Whether these deposits trigger local inflammation and disturb pulmonary gas exchanges is not known. The aim of this study was to assess the acute effects of high-wattage electronic cigarette vaping with or without nicotine on lung inflammation biomarkers, transcutaneous gas tensions, and pulmonary function tests in young and healthy tobacco smokers. Acute effects of vaping without nicotine on arterial blood gas tensions were also assessed in heavy smokers suspected of coronary artery disease. Using a single-blind within-subjects study design, 25 young tobacco smokers underwent three experimental sessions in random order: sham-vaping and vaping with and without nicotine at 60 W. Twenty heavy smokers were also exposed to sham-vaping (n = 10) or vaping without nicotine (n = 10) in an open-label, randomized parallel study. In the young tobacco smokers, compared with sham-vaping: 1) serum club cell protein-16 increased after vaping without nicotine (mean ± SE, -0.5 ± 0.2 vs. +1.1 ± 0.3 µg/l, P = 0.013) and vaping with nicotine (+1.2 ± 0.3 µg/l, P = 0.009); 2) transcutaneous oxygen tension decreased for 60 min after vaping without nicotine (nadir, -0.3 ± 1 vs. -15.3 ± 2.3 mmHg, P < 0.001) and for 80-min after vaping with nicotine (nadir, -19.6 ± 2.8 mmHg, P < 0.001). Compared with sham vaping, vaping without nicotine decreased arterial oxygen tension for 5 min in heavy-smoking patients (+5.4 ± 3.3 vs. -5.4 ± 1.9 mmHg, P = 0.012). Acute vaping of propylene glycol/glycerol aerosol at high wattage with or without nicotine induces airway epithelial injury and sustained decrement in transcutaneous oxygen tension in young tobacco smokers. Intense vaping conditions also transiently impair arterial oxygen tension in heavy smokers.

Nurse middle managers' proactive work behavior: antecedents and consequences on innovative work behavior and job performance.

PURPOSE: Healthcare organizations require more proactive behaviors from nursing professionals. However, nurse managers' proactivity has rarely been analyzed in the literature and little is known about the antecedents and consequences of their proactive behavior at work. This study examines the relationships between job characteristics (i.e. job autonomy and job variety), psychological empowerment, proactive work behavior and job effectiveness indicators (i.e. innovative work behavior, job performance). We tested a model in which psychological empowerment and proactive work behavior sequentially mediate the relationship between job characteristics and job effectiveness. DESIGN/METHODOLOGY/APPROACH: A cross-sectional study was conducted among nurse middle managers from a French hospital (N = 321). A hypothetical model was developed based on existing theory. Structural equation modeling was used to test the hypotheses. FINDINGS: Results show that psychological empowerment and proactive work behavior fully mediate the relationship between job characteristics and innovative work behavior, and partially mediate the relationship between job characteristics and job performance. ORIGINALITY/VALUE: This study provides insights for understanding how job characteristics can contribute to fostering the proactivity of nurse middle managers and how their proactive work behavior can be positively related to innovative work behavior and job performance. Findings raise several implications for hospital administrators and upper management seeking new ways to enhance nurse middle managers' proactive work behavior and push further their effectiveness at work.

Development, validation and clinical use of a LC-MS/MS method for the simultaneous determination of the nine main antituberculosis drugs in human plasma.

The treatment of tuberculosis, in particular the multi-drug resistant tuberculosis, remains a challenge mainly because of the therapy duration and the pharmacokinetic variability of the drugs included in the regimen. The monitoring of antituberculosis drugs is a recent tool that could improve the outcome of patients. We developed a LC-MS/MS method allowing the simultaneous quantification of the four first-line drugs (isoniazid, rifampicin, pyrazinamide and ethambutol), a metabolite of isoniazid (acetylisoniazid) and the five main second-line drugs (rifabutin, levofloxacin, moxifloxacin, linezolid and bedaquiline). An isotopologue standard was used for each drug. The protein precipitation was performed with acetonitrile and the separation was carried out using an EC-18 column and a gradient elution. The validated ranges for each drug were adapted to monitor the plasma concentration at 2 h (peak) and 6 h to evaluate their enteric absorption. The intermediate precision (CV) and the trueness at the limit of quantification were ≤ 10.1% and ≤ 10.7%, respectively. Preliminary data were obtained for 12 patients. The results showed that 38% of the patients had infra-therapeutic levels for both rifampicin and isoniazid, that the leading cause of an impaired oral absorption seemed to be malabsorption and that the effective concentrations for rifampicin were in the lower range of the therapeutic interval.

Acquired Zinc Deficiency Mimicking Acrodermatitis Enteropathica in a Breast-Fed Premature Infant.

We present a case of a transient acquired zinc deficiency in a breast-fed, 4-month-old-male prematurely born infant, with acrodermatitis enteropathica-like symptoms such as crusted, eroded, erythemato-squamous eruption in periorificial and acral patterns. The laboratory investigations showed low zinc levels in the infant's and the mother's serum and in the mother's milk; genetic analysis did not show any mutation in the SLC39A4 gene, involved in acrodermatitis enteropathica. Acquired zinc deficiency is often found in premature infants because of their increased requirement, the low serum and milk zinc levels in breastfeeding women being also an important risk factor, as in this case. A prompt zinc supplementation is essential for the good prognosis of the disease.

Norm and Deviance-Seeking Personal Orientation Scale (NDPOS) Adapted to the Organisational Context.

Deviance theory introduces a behavioural view on constructive and destructive deviance to explain how an individual's intent can harm or improve organisational well-being. However, to our knowledge, no scale exists that evaluates the personal orientation aspect of deviance and normativity. This article discusses the creation of the Norm and Deviance-Seeking Personal Orientation Scale (NDPOS). To create this scale, we studied the psychometric properties of the instrument using data from French workers. NDPOS exploratory analysis indicated a 12-item scale composed of four factors: normative conformity, normative rule adequacy, deviant performance seeking, and deviant proactivity seeking. Confirmatory factor analysis corroborated the factorial structure in four sub-scales. Convergent and discriminant validity indicated that deviant dimensions were positively related to expressing voice, cognitive flexibility, and deviant behaviours, whereas normativity dimensions were negatively or not related to these behaviours. Furthermore, opposite relations between the conformity construct and the four factors were observed. Practical implications and suggestions for the development of future research on constructive deviance theory are discussed.

Differential Effects of E-Cigarette on Microvascular Endothelial Function, Arterial Stiffness and Oxidative Stress: A Randomized Crossover Trial.

Propylene glycol and glycerol are electronic cigarettes vehicles allowing liquid vaporization and nicotine transport. The respective effects of these different constituents on the cardiovascular system are unknown. We assessed the differential effects of vehicles (propylene glycol and glycerol) and nicotine on microcirculatory function, arterial stiffness, hemodynamic parameters and oxidative stress. Twenty-five tobacco smokers were exposed to vaping with and without nicotine, and sham vaping, in a randomized, single blind, 3-period crossover design study. Neither sham-vaping nor vaping in the absence of nicotine resulted in modifications of cardiovascular parameters or oxidative stress. In contrast, vaping with nicotine: 1) impaired acetylcholine mediated vasodilation (mean ± standard error mean) (area under curve, perfusion unit (PU), 3385 ± 27PU to 2271 ± 27PU, p < 0.0001); 2) increased indices of arterial stiffness, namely augmentation index corrected for heart rhythm (-3.5 ± 1.5% to 1.9 ± 2.3%; p = 0.013) and pulse wave velocity (4.9 ± 0.1 m.s-1 to 5.3 ± 0.1 m.s-1; p < 0.0001); 3) increased systolic and diastolic blood pressures as well as heart rate (all p < 0.0001) and finally; 4) raised plasma myeloperoxidase (median [interquartile range]) (13.6 ng.ml-1 [10-17.7] to 18.9 ng.ml-1 [12.2-54.4], p = 0.005). Our findings demonstrated that high temperature e-cigarette vehicle vaporization does not alter micro- and macro-vascular function, and oxidative stress, and that these effects are solely attributable to nicotine.

Evaluation of total body weight and body mass index cut-offs for increased cefazolin dose for surgical prophylaxis.

French and American guidelines recommend increased dosage regimens of cefazolin (CFZ) for surgical prophylaxis in patients with a body mass index (BMI) ≥ 35 kg/m2 or with a total body weight (TBW) ≥ 120 kg. The objective of this study was to evaluate the accuracy of these cut-offs in identifying patients who require CFZ dose adjustment. A pharmacokinetic study was conducted in patients of varying TBW and BMI who received 2 g of CFZ intravenously for prophylaxis prior to digestive surgery. Adequacy of therapy, defined as a serum concentration of unbound CFZ (fCFZ) ≥ 4 mg/L, was evaluated 180 min (T180) and 240 min (T240) after the start of CFZ infusion. Possible factors associated with insufficient fCFZ levels were also assessed. A P-value of <0.05 was considered statistically significant. A total of 63 patients were included in the study, categorised according to BMI (<35 kg/m2, 20 patients; and ≥35 kg/m2, 43 patients) and TBW (<120 kg, 41 patients; and ≥120 kg, 22 patients). All patients had adequate drug levels at T180 but only 40/63 patients (63%) had adequate levels at T240. At T240, therapy was adequate in 15/20 patients (75%) and 25/43 patients (58%) with BMI <35 kg/m2 and ≥35 kg/m2, respectively (P = 0.20), and in 28/41 patients (68%) and 12/22 patients (55%) with TBW <120 kg and ≥120 kg, respectively (P = 0.28). No factor associated with insufficient fCFZ was identified. In conclusion, current BMI and TBW cut-offs are poor indicators of which patients could benefit from increased CFZ dosage regimens.

Rapid quantification of six ß-lactams to optimize dosage regimens in severely septic patients.

A fast analytical procedure was developed for the simultaneous quantification of cefepime (CEF), meropenem (MEM), ceftazidime (CZA), cefuroxime (CFX), aztreonam (AZT), and piperacillin (PIP) in serum of intensive care patients. The ß-lactam pharmacokinetic parameters can be altered in severe sepsis due to changes in the distribution, the metabolism and the elimination process. Therapeutic drug monitoring (TDM) of ß-lactams is therefore recommended in critically ill patients. The plasma samples were spiked with cefoperazone as internal standard and proteins were precipitated with methanol. The different ß-lactams were separated with high performance liquid chromatography within 18 min, and quantified by UV spectrophotometry with a diode array detector. The method was validated by means of the accuracy profile approach based on ß expectation tolerance intervals. The acceptance limits were settled at ± 30% according to the regulatory requirements. Assay validation demonstrated good performance for all ß-lactams analyzed in terms of trueness, repeatability, linearity and intermediate precision over the range of 2-200 µg/mL. The simple extraction procedure provides respective absolute and relative recoveries ranging from 70% to 86% and from 66% to 89% for all the ß-lactams analyzed. Few interferences were observed and the method was easily applicable to TDM in intensive care patients. The quantification of ß-lactams should allow for antibiotic regimen adjustment in critically ill patients.