Update on adrenal steroid hormone biosynthesis and clinical implications

Steroid biosynthesis is a complex process in which cholesterol is converted to steroid hormones with the involvement of multiple enzymes and cofactors. Inborn conditions affecting adrenal steroidogenesis are relatively common in paediatric practice and have serious implications on patient mortality and morbidity. This paper provides an overview of novel insights into human adrenal steroid biosynthesis. Inborn errors of steroidogenesis associated with congenital adrenal hyperplasia are discussed, with a particular focus on the pathophysiology and clinical features of 21-hydroxylase deficiency. The final section of the review presents more recent findings and clinical implications of adrenal-specific androgen biosynthesis

Fatigue crack propagation in HSLA steel specimens subjected to unordered and ordered load spectra

Prediction of fatigue crack propagation in metallic structures subjected to dynamic random load spectra, containing variable overloads and underloads, is challenging because of possible retardation and acceleration effects. In this paper, fatigue crack growth behaviour under random spectrum load is investigated on ESE(T) specimens made of DNV 460 steel, which is an HSLA steel widely used in the offshore industry. A reference spectrum composed of a sequence of random loads is transferred into various reduced and ordered spectra. Reduced spectra have been defined based on a peak-valley segmentation algorithm and on the deletion of non-damaging events. Ordered spectra consist of block loading sequences determined by rainflow counting methods. Specific control software has been developed that allows to execute the K (stress intensity factor) controlled experimental program and perform on-line crack growth measurement using a material compliance method. The different spectra are compared in terms of total crack extension and retardation in crack growth rate. Algorithms for crack growth simulation have been implemented in Abaqus using both existing and adapted plastic zone models. Numerical results are critically compared to the experimental data

Thalamocortical connectivity in experimentally-induced migraine attacks: A pilot study

In this study we used nitroglycerin (NTG)-induced migraine attacks as a translational human disease model. Static and dynamic functional connectivity (FC) analyses were applied to study the associated functional brain changes. A spontaneous migraine-like attack was induced in five episodic migraine (EM) patients using a NTG challenge. Four task-free functional magnetic resonance imaging (fMRI) scans were acquired over the study: baseline, prodromal, full-blown, and recovery. Seed-based correlation analysis (SCA) was applied to fMRI data to assess static FC changes between the thalamus and the rest of the brain. Wavelet coherence analysis (WCA) was applied to test time-varying phase-coherence changes between the thalamus and salience networks (SNs). SCA results showed significantly FC changes between the right thalamus and areas involved in the pain circuits (insula, pons, cerebellum) during the prodromal phase, reaching its maximal alteration during the full-blown phase. WCA showed instead a loss of synchronisation between thalami and SN, mainly occurring during the prodrome and full-blown phases. These findings further support the idea that a temporal change in thalamic function occurs over the experimentally induced phases of NTG-induced headache in migraine patients. Correlation of FC changes with true clinical phases in spontaneous migraine would validate the utility of this model

Efeito da aplicação de diferentes tratamentos térmicos no conteúdo de resíduo de anticoccidiano em carne de frango.

Resumo: Anticoccidianos são compostos utilizados na prevenção de uma doença parasitária muito comum na criação de frangos de corte. A nicarbazina é um complexo constituído por 4,4´-dinitrocarbanilida (DNC) e 2-hidroxi-4,6- dimetil-pirimidina (HDP) amplamente utilizado como anticoccidiano. Contudo, a deposição de DNC em carne de frango é uma preocupação recorrente. O objetivo deste estudo foi avaliar o efeito de tratamentos térmicos convencionais sobre o conteúdo de DNC em carne de frango. A carne contaminada com DNC foi obtida de frangos alimentados com ração contendo nicarbazina (180 mg.kg-1 ). Foram realizados 2 experimentos com carne de frango submetida ao aquecimento por cozimento, grelha, micro-ondas, fritura e forneamento. No primeiro, realizou-se avaliação cinética da degradação de DNC na carne, enquanto que no segundo comparou-se a eficiência dos tratamentos. As concentrações de DNC na carne foram determinadas por LC-MS/MS. Os resultados indicaram que os tratamentos induziram a degradação de DNC na faixa de 52 a 69%. O cozimento foi o procedimento mais eficiente dentre os tratamentos avaliados. A degradação nos procedimentos com grelha, micro-ondas e fritura não diferiu (p?0,05) do valor para o cozimento. A redução dos níveis de DNC foi associada à hidrólise desta molécula. Considerando a legislação atual, que regulamenta o monitoramento de DNC, confirmou-se que os tratamentos podem tornar a carne mais segura ao consumidor