Abstract
The aim of the study was to evaluate adrenal axis hyperactivation measuring hair cortisol levels, and its influence on the relationship among metabolic parameters, inflammation markers and ...androgens in adult women with PCOS. 44 women (18–34 years) with PCOS diagnosis and a control group of 49 healthy women (19–35 years) were included. In both gropus body mass index (BMI) was calculated and waist circumference (WC) was measured. Hair cortisol, total serum testosterone (TT), serum cortisol, 25 OH vitamin D (25OHD), insulin, high sensitivity C-reactive protein (hsCRP), triglycerides (TG), HDL cholesterol (HDL), glucose and leptin were measured. Bioavailable testosterone (bioT) was calculated. Hair cortisol concentration was higher and significantly different in PCOS patients compared to the control group (130 vs 63 pg/mg of hair, p < 0.001). Subsequently, patients with PCOS were divided into two groups according to hair cortisol levels: group 1 with normal hair cortisol concentration and group 2 with levels above the upper limit of the reference values (128 pg/mg of hair). In group 2, TT significantly correlated with 25OHD, hsCRP, TG/HDL index, BMI, WC, insulin and HOMA (p < 0.05); bioT correlated with hsCRP and leptin (p < 0.05). Finally, 25OHD was inversely correlated with leptin and with TG/HDL index (p < 0.05). High hair cortisol concentration in patients with PCOS confirmed hyperactivation of the HPA axis. The associations observed were only found in patients with PCOS with high hair cortisol levels (> 128 pg/mg of hair), showing a possible effect of HPA axis in these associations.
Vitamin D deficiency has been related with metabolic alterations in polycystic ovary syndrome (PCOS). As well, hyperactivation of adrenal axis can be programmed early in life and could be related ...later with PCOS development. Our aim was to establish the relationship between vitamin D and adrenal parameters with metabolic alterations and inflammation markers in PCOS. In 73 patients and 33 controls, 25-hydroxyvitamin D (25-OH-D), total and bioavailable testosterone (TT and bioT), androstenedione (A4), SHBG, cortisol, insulin, and C-reactive protein (hs-CRP) were determined; HOMA and lipid accumulation product (LAP) index were calculated. All parameters were higher in patients than in controls, except for SHBG and 25-OH-D which were lower. Binary regression analysis showed that differences in TT, bioT, A4, insulin and HOMA were independent of body mass index and waist circumference but SHBG, hs-CRP, LAP and 25-OH-D were related to body weight and fat distribution. Binary logistic regression analysis showed that cortisol and 25-OH-D could be associated to PCOS development. Correlations found between LAP and insulin, HOMA and hs-CRP confirm it is a good indicator of metabolic complications. Vitamin D and cortisol association to PCOS development justifies future research to understand the role of vitamin D in PCOS and analyze patient's perinatal history and its possible relationship with hyperactivation of adrenal axis in adult life.
Summary
Context
Acromegaly is characterized by GH excess and insulin resistance. It is not known which of these disorders is responsible for the increased atherogenic risk in these patients.
...Objective
To analyse the associations of GH and homoeostasis model assessment (HOMA) with biomarkers of cardiovascular disease and to compare the above‐mentioned variables between patients with active acromegaly and controls.
Design and setting
This open cross‐sectional study was conducted at a University Hospital.
Patients
Twenty‐two outpatients were compared with sex‐ and age‐matched control subjects.
Main outcomes
Included clinical features, hormonal status, markers of insulin resistance, lipoprotein profile and biomarkers of cardiovascular disease.
Results
Patients presented higher triglyceride (median IQR) (1·21·1–1·6 vs 0·90·6–1·1 mm, P < 0·05), low‐density lipoprotein‐cholesterol (LDL‐C) (mean ± SD) (3·5 ± 0·9 vs 3·0 ± 0·7mm, P < 0·05), apoB (0·98 ± 0·23 vs 0·77 ± 0·22 g/l, P < 0·05), free fatty acid (0·69 ± 0·2 vs 0·54 ± 0·2 mM, P < 0·05), oxidized‐LDL (120 ± 22 vs 85 ± 19 U/l, P < 0·05) and endothelin‐1 (0·90 ± 0·23 vs 0·72 ± 0·17 ng/l, P < 0·05) levels, increased cholesteryl ester transfer protein (CETP) activity (179 ± 27 vs 138 ± 30%/ml/h, P < 0·01) and lower C reactive protein (CRP) (0·250·1–0·9 vs 0·850·4–1·4 mg/l; P < 0·05) levels than control subjects. Vascular cell adhesion molecule (VCAM‐1) concentration was not different. By multiple linear regression analyses, HOMA explained the variability of triglycerides (25%), high‐density lipoprotein‐cholesterol (HDL‐C) (30%) and CETP activity (28%), while GH independently predicted LDL‐C (18%), oxidized‐LDL (40%) and endothelin‐1 levels (19%).
Conclusions
In patients with active acromegaly, GH excess contributes to the development of insulin resistance, and the interaction between both disturbances would be responsible for the appearance of atherogenic pro‐oxidative and pro‐inflammatory factors. Insulin resistance would be preferably associated with an atherogenic lipoprotein profile and to high CETP activity, while high GH levels would independently predict the increase in LDL‐C, ox‐LDL and endothelin‐1.
Introduction Dans certaines pathologies comme les ventricules fentes, le placement de drain ventriculaire peut être associé à des malpositionnements (13 %). Il demande un contrôle postopératoire et ...conduit parfois à des reprises chirurgicales. Nous avons donc mis au point une technique permettant un contrôle peropératoire de la mise en place des drains ventriculaires. Patient et méthode Dans notre centre, la mise en place de drain ventriculo-péritonéal se fait à l’aide d’une neuro-navigation et malgré cela, nous avons déjà observé (surtout lorsque les ventricules sont fentes) des positions sous optimales. Après la mise en place du matériel, nous réalisons une imagerie 3D avec l’Artis Zeego 2.0. (Siemens) alors que le patient est encore dans la têtière de Mayfield. L’image 3D obtenue est fusionnée à un CT ou à une IRM préopératoire. Résultats Nous avons donc utilisé cette technique chez un patient de 74 ans présentant une hydrocéphalie normotensive. Après la mise en place du drain et la fermeture de la peau, nous avons réalisé une imagerie 3D. La procédure ne dure pas plus de 5 minutes. La dose d’irradiation reçue par le patient était de 46,1 mGy (un CT cérébral émet entre 500 et 700 mGy). La reconstruction 3D obtenue est ensuite fusionnée par le programme à un CT préopératoire. La fusion permet ainsi de montrer une position du drain optimale. Conclusion Cette technique est donc rapide, permet d’avoir un contrôle de qualité peropératoire surtout pour des cas plus difficiles comme les ventricules fentes et permet de diminuer de 10 à 15 fois l’irradiation reçue par le patient.
Multivariate normal distribution is base for many statistical techniques, including ordinary least square inference. Here we show that in order to make research on Internationalization of Companies, ...more flexible approach is needed, namely partial least squares (PLS). It is a nonparametric technique, used in Structural Equation Modeling (SEM), which makes no distributional assumptions and also may be applied with small sample sizes. In this study we discuss on regularity conditions for PLS from the perspective of semi-continuous covariance which fills the gap in the current studies. The stochastic aspects, especially those related to usage of PLS-SEM, can be well integrated to the topologically grounded regression, where jumps in the covariances can occur. The purpose of the research is to analyze and understand the impact of the Incentive System (IS) for Innovation, within the scope of the National Strategic Reference Framework (QREN) 2014-2020, on the Internationalization of Portuguese Small and Medium Enterprises (SMEs). We study stochastic aspects of theoretical model which aggregates the variables Product Innovation, Marketing Innovation, Organizational Innovation and Working Conditions as determinants of Internationalization of Companies.
Data were collected based on a quantitative methodology, through a self-completion questionnaire using the Likert psychometric scale, which registered 120 participants. Organizational Innovation (exogenous latent construct) and Product Innovation have shown a statistically significant indirect effect on the Internationalization of Companies (endogenous latent construct) through Marketing Innovation. The latter has a direct effect on the Internationalization (target construct). However, Working Conditions has the greatest impact on Internationalization, meaning that measures such as increasing wages, decreasing the use of temporary work and precarious work conversion into labor effective relations have a very relevant direct effect on the Internationalization of Portuguese SMEs.
Border officers experience stressful moments during the working day at the border point at Lisbon airport (Portugal) that can lead to "emotional exhaustion," which is the core component of burnout, ...and relates with "cognitive fatigue (weariness)" and "physical fatigue." These theoretical concepts cannot be measured (or observed) directly by what are considered latent variables/constructs that are available in Shirom-Melamed Burnout Measure (SMBM). These constructs are, however, operationalized by the questions available in the SMBM, which correspond to observed variables (or manifest variables) expressed in an ordinal scale of seven categories. This questionnaire, reliable and internationally validated, was used in our research and considering the specialized literature, we proposed a hypothetical structural path model that expresses a priori perceptions about the causal relationships between the mentioned latent constructs, where "physical fatigue" is the target construct. A reflective model was estimated based on the sample of primary data and using a Variance-Covariance estimator of Structural Equations Modeling (VB-SEM), the consistent Partial Least Squares (PLSc), that corrects for bias to consistently estimate SEM's with common factors. The results obtained allow a better understanding of the profile and characteristics of Portuguese border officers who work at Lisbon airport, as well as reveal that the latent exogenous construct "emotional exhaustion" has a high positive direct effect on the "cognitive fatigue," and through this latter (mediator construct), an indirect effect on the endogenous construct "physical fatigue." In turn, "cognitive fatigue" has the greatest positive direct effect on "physical fatigue." The biggest difference identified was between the direct effect of "Emotional exhaustion" on "Physical fatigue," which is higher for workers with more years of service, as expected. However, the multigroup analysis (using the nonparametric Permutation test) showed that this difference was not statistically significant.
In this article, we describe and analyze the chaotic behavior of a conductance-based neuronal bursting model. This is a model with a reduced number of variables, yet it retains biophysical ...plausibility. Inspired by the activity of cold thermoreceptors, the model contains a persistent Sodium current, a Calcium-activated Potassium current and a hyperpolarization-activated current (I
) that drive a slow subthreshold oscillation. Driven by this oscillation, a fast subsystem (fast Sodium and Potassium currents) fires action potentials in a periodic fashion. Depending on the parameters, this model can generate a variety of firing patterns that includes bursting, regular tonic and polymodal firing. Here we show that the transitions between different firing patterns are often accompanied by a range of chaotic firing, as suggested by an irregular, non-periodic firing pattern. To confirm this, we measure the maximum Lyapunov exponent of the voltage trajectories, and the Lyapunov exponent and Lempel-Ziv's complexity of the ISI time series. The four-variable slow system (without spiking) also generates chaotic behavior, and bifurcation analysis shows that this is often originated by period doubling cascades. Either with or without spikes, chaos is no longer generated when the I
is removed from the system. As the model is biologically plausible with biophysically meaningful parameters, we propose it as a useful tool to understand chaotic dynamics in neurons.
Objective To establish the relationship between androgens and cardiovascular disease (CVD) risk factors in the menopausal transition.
Methods A total of 124 women were divided into four groups: 29 ...premenopausal (PreM), 35 women in the menopausal transition still menstruating (MTM), 29 women in the menopausal transition with 3-6 months amenorrhea (MTA), and 31 postmenopausal women (PostM). Levels of triglycerides, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, glucose and insulin were assayed in all samples and waist circumference was measured. In a subgroup of 83 women (19 PreM, 21 MTM, 28 MTA and 15 PostM), levels of total testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS) and estradiol were determined. The free androgen index, Homeostasis Model Assessment (HOMA) index, Quantitative Insulin Sensitivity Check Index (QUICKI) and McAuley index, estradiol total testosterone and triglyceride HDL cholesterol ratios were calculated.
Results Androstenedione was higher in MTA vs. PostM women (p < 0.05); DHEAS was higher in PreM women vs. the other three groups (p < 0.05). Sex hormone binding globulin (SHBG) in MTM women was higher than in MTA women (p < 0.05); the free androgen index was lower in MTM women than in MTA and PostM women. SHBG and the free androgen index showed negative and positive correlations, respectively with waist circumference, insulin resistance and lipids. In a multiple regression analysis, considering waist circumference, neither free androgen index nor SHBG showed significant differences between groups. The waist circumference correlated only with SHBG (p = 0.022) and correlations between SHBG and insulin resistance markers continued to be significant, but relationships between SHBG and lipoproteins and all correlations found with free androgen index were lost.
Conclusions An increment in the androgenic milieu that correlates with abdominal fat, insulin resistance and atherogenic lipoproteins becomes evident after the menopausal transition and suggests that evaluation of cardiovascular disease risk in these women should include androgens, considering that abdominal obesity is one of the main determinants of the relationship between androgenic parameters and cardiovascular risk factors.
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