Формирование творческой речевой активности дошкольников с функциональными нарушениями зрения

Рассматриваются основные этапы формирования навыков творческого рассказывания у дошкольников с функциональными нарушениями зрения, перечисляются эффективные приемы стимулирования творческой речевой активности дошкольников с ослабленным зрение

Effects of the pattern of glucocorticoid replacement on neural processing, emotional reactivity and well-being in healthy male individuals:study protocol for a randomised controlled trial

BACKGROUND: Deviation from the physiological glucocorticoid dynamics (circadian and underlying ultradian rhythmicity) is a common characteristic of various neuropsychiatric and endocrine disorders as well as glucocorticoid-based therapeutics. These states may be accompanied by neuropsychiatric symptomatology, suggesting continuous dynamic glucocorticoid equilibrium is essential for brain homeostasis. METHODS/DESIGN: The study consists of two parts. The preliminary stage of the study aims to validate (technically and pharmacologically) and optimise three different patterns of systemic cortisol administration in man. These patterns are based on the combinatory administration of metyrapone, to suppress endogenous cortisol production, and concurrent hydrocortisone replacement. The second, subsequent, core part of the study is a randomised, double-blinded, placebo-controlled, crossover study, where participants (healthy male individuals aged 18–60 years) will undergo all three hydrocortisone replacement schemes. During these infusion regimes, we plan a number of neurobehavioural tests and imaging of the brain to assess neural processing, emotional reactivity and perception, mood and self-perceived well-being. The psychological tests include: ecological momentary assessment, P1vital Oxford Emotional Test Battery and Emotional Potentiated Startle Test, Leeds Sleep Evaluation Questionnaire and the visual working memory task (n-back). The neuroimaging protocol combines magnetic resonance sequences that capture data related to the functional and perfusion status of the brain. DISCUSSION: Results of this clinical trial are designed to evaluate the impact (with possible mechanistic insights) of different patterns of daily glucocorticoid dynamics on neural processing and reactivity related to emotional perception and mood. This evidence should contribute to the optimisation of the clinical application of glucocorticoid-based therapeutics. TRIAL REGISTRATION: UK Clinical Research Network, IRAS Ref: 106181, UKCRN-ID-15236 (23 October 2013

Glucocorticoid ultradian rhythmicity differentially regulates mood and resting state networks in the human brain: A randomised controlled clinical trial

Adrenal glucocorticoid secretion into the systematic circulation is characterised by a complex rhythm, composed of the diurnal variation, formed by changes in pulse amplitude of an underlying ultradian rhythm of short duration hormonal pulses. To elucidate the potential neurobiological significance of glucocorticoid pulsatility in man, we have conducted a randomised, double-blind, placebo-controlled, three-way crossover clinical trial on 15 healthy volunteers, investigating the impact of different glucocorticoid rhythms on measures of mood and neural activity under resting conditions by recruiting functional neuroimaging, computerised behavioural tests and ecological momentary assessments. Endogenous glucocorticoid biosynthesis was pharmacologically suppressed, and plasma levels of corticosteroid restored by hydrocortisone replacement in three different regimes, either mimicking the normal ultradian and circadian profile of the hormone, or retaining the normal circadian but abolishing the ultradian rhythm of the hormone, or by our current best oral replacement regime which results in a suboptimal circadian and ultradian rhythm. Our results indicate that changes in the temporal mode of glucocorticoid replacement impact (i) the morning levels of self-perceived vigour, fatigue and concentration, (ii) the diurnal pattern of mood variation, (iii) the within-network functional connectivity of various large-scale resting state networks of the human brain, (iv) the functional connectivity of the default-mode, salience and executive control networks with glucocorticoid-sensitive nodes of the corticolimbic system, and (v) the functional relationship between mood variation and underlying neural networks. The findings indicate that the pattern of the ultradian glucocorticoid rhythm could affect cognitive psychophysiology under non-stressful conditions and opens new pathways for our understanding on the neuropsychological effects of cortisol pulsatility with relevance to the goal of optimising glucocorticoid replacement strategies

Οπτικές ιδιότητες φωτοχρωμικών υλικών

The development of structures of nanometer and micrometer size over the last few years has given rise to research into new materials, so that the present structures to be improved. This need for improvement has driven the search for new materials which go through mechanical transformation when interacting with light. The macromolecular polymeric matrices with incorporated photochromic molecules belong to this category of materials. The present project studies the properties of such materials. In particular, thin polymeric films of PEMMA doped with the photochromic compound Spiropyran in various concentrations have been studied. The molecule of Spiropyran is transformed into Merocyanine when exposed to ultraviolet radiation and back to Spyropyran when exposed to visible radiation. In this study, the absorption spectra of the doped films have been taken and the maximum absorption wavelength corresponding to each of these thin films has been calculated. It has been found that in small concentrations of Spiropyran (less than 10%) the absorption coefficient increases almost in linearly with the concentration of the photochromic molecule; however saturation is observed at greater concentrations. Subsequently, the change of the refractive index between the non excited and excited state respectively of these thin films has been studied, as well as the way that refractive index is changing in terms of the concentrations of Spiropyran in polymeric film of PEMMA. The waveguiding experiment which has been set-up for this purpose measures with accuracy the refractive index (third decimal place) as well as the thickness of those thin films (accuracy ~ 0,3μm). The measurements have been carried out using visible and infrared lasers as sources of radiation. We have observed that refractive index is increasing with the increase of Spiropyran in the PEMMA.Η ανάπτυξη δομών σε κλίμακα της τάξης μεγέθους του μικρομέτρου και νανομέτρου, έχει δώσει το έναυσμα τα τελευταία χρόνια για περαιτέρω έρευνα στην ανάπτυξη νέων υλικών, ώστε να βελτιωθούν οι ήδη υπάρχουσες δομές. Η επικείμενη αυτή ανάγκη, οδήγησε στη έρευνα υλικών τα οποία υπόκεινται σε μηχανικές αλλαγές κατά την αλληλεπίδρασής τους με φως. Μία τέτοια κατηγορία είναι οι μακρομοριακές πολυμερικές μήτρες στις οποίες έχουν ενσωματωθεί φωτοχρωμικά μόρια. Η παρούσα εργασία έγινε με σκοπό τη μελέτη τέτοιων υλικών. Ποιο συγκεκριμένα, μελετήθηκαν λεπτά υμένια πολυμερικών μητρών PEMMA, οι οποίες είχαν εμπλουτιστεί με φωτοχρωμικά μόρια σπιροπυρανίου σε διάφορες συγκεντρώσεις. Το μόριο του σπιροπυρανίο διεγείρεται όταν εκτείθεται σε υπεριώδη ακτινοβολία και αποδιεγείρεται όταν εκτείθεται σε ορατή ακτινοβολία. Στη μελέτη αυτή, πραγματοποιήθηκε σε πρώτη φάση η λήψη των φασμάτων απορρόφησης και η εύρεση του μήκους κύματος που αντιστοιχεί στο μέγιστο της απορρόφησης για καθένα από αυτά τα λεπτά υμένια, καθώς και ο υπολογισμός του συντελεστή απορρόφησης σε αυτό το μήκος κύματος. Παρατηρήθηκε ότι, για μικρές συγκεντρώσεις του σπιροπυρανίου (λιγότερο από 10%) ο συντελεστής απορρόφησης αυξάνει σχεδόν γραμμικά με την αύξηση της συγκέντρωσης του σπιροπυρανίου (SP) ενώ υπάρχει κορεσμός για μεγαλύτερες περιεκτικότητες. Σε δεύτερη φάση, πραγματοποιήθηκε η μελέτη της μεταβολής του δείκτη διάθλασης ανάμεσα στην μή διεγερμένη και στη διεγερμένη αντίστοιχα κατάσταση των λεπτών αυτών υμενίων, καθώς και ο τρόπος που μεταβάλλεται ο δείκτης διάθλασης των λεπτών αυτών υμενίων συναρτήση της συγκέντρωσης σπιροπυρανίου μέσα στην μακρομοριακή πολυμερική μήτρα PEMMA. Η μέθοδος κυματοδηγών που αναπτύχθηκε για το σκοπό αυτό, μετράει με μεγάλη ακρίβεια τόσο τον δείκτη διάθλασης (ακρίβεια στο τρίτο δεκαδικό ψηφίο) όσο και το πάχος (ακρίβεια ~ 0,3μm) των λεπτών αυτών υμενίων. Οι μετρήσεις πραγματοποιήθηκαν χρησιμοποιώντας ως πηγή ακτινοβολίας λέιζερ ορατού και υπερύθρου μήκους κύματος. Παρατηρήθηκε αύξηση στον δείκτη διάθλασης καθώς αυξάνεται η συγκέντρωση του φωτοχρωμικού μορίου της σπιροπυράνης μέσα στην πολυμερική μήτρα PEMMA και πριν και μετά την διέγερση των δειγμάτων μας

Intracerebroventricular administration of streptozotocin as an experimental approach to Alzheimer's disease

The in vivo experimental simulation of Alzheimer's disease (AD) has been a field of paramount importance for Experimental Medicine and Neuroscience for more than 20 years. We herein provide a short overview of an experimental approach to sporadic AD that is based on the insulin-resistant state induced in the brains of animals following the intracerebroventricular (icv) administration of streptozotocin (STZ) at low doses. The icv administration of STZ is considered as an established, standardized and reproducible approach to sporadic AD, central aspects of the pathology of which it can reliably simulate

The regulatory role of neurotensin on the hypothalamic-anterior pituitary axons: emphasis on the control of thyroid-related functions

Neurotensin (NT) is a 13 amino acid neurohormone and/or neuromodulator, located in the synaptic vesicles and released from the neuronal terminals in a calcium-dependent manner. This peptide is present among mammalian and nonmammalian species, mainly in the central nervous system and the gastrointestinal tract. Due to its neuroendocrine activity, NT has been related to the pathophysiology of a series of disorders, such as schizophrenia, drug-abuse, Parkinson's disease, cancer, stroke, eating disorders and other neurodegenerative conditions. Moreover, NT participates in the physiology of pain-induction, central blood pressure control and inflammation. NT also plays an important interactive role in all components of the hypothalamic-anterior pituitary circuit, which is mediated by an endocrine, paracrine or/and autocrine manner, towards most of the anatomical regions that define this circuit. A considerable amount of data implicates NT in thyroid-related regulation through this circuit, the exact mechanisms of which should be further investigated for the potential development of more targeted approaches towards the treatment of thyroid-related endocrine diseases. The aim of this study was to provide an up-to-date review of the literature concerning the regulatory role of NT on the hypothalamic-anterior pituitary axons, with an emphasis on the control of thyroid-related functions

Biphasic Response of Astrocytic Brain-Derived Neurotrophic Factor Expression following Corticosterone Stimulation

Novel research studies indicate multivarious interactions of glucocorticoid hormones (GCs) with the brain-derived neurotrophic factor (BDNF), regulating important aspects of neuronal cell physiology. While there is recent evidence of the chronic effects of GC stimulation on BDNF levels, as well as of the role of BDNF stimulation in the type of genomic effects following activation of GC-sensitive receptors, no data exist concerning the acute effects of GC stimulation on BDNF/TrkB gene expression. To address this question, we conducted a chrono-pharmacological study on rodent glial cells, astrocytes, which express the BDNF receptor, TrkB, following corticosterone administration. mRNA levels of BDNF and TrkB were estimated 1, 6, 12 and 24 h post-treatment. Selective inhibitors for GC-sensitive receptors and TrkB were used to decipher the molecular pathways of the effects observed. Our data support a biphasic response of BDNF expression after corticosterone stimulation. This response is characterized by a rapid TrkB phosphorylation-dependent upregulation of BDNF mRNA within the first hour, followed by a glucocorticoid receptor (GR)-dependent downregulation of BDNF mRNA, evident at 6, 12 and 24 h, with a direct impact on the protein levels of mature BDNF. Finally, a second pulse of corticosterone administration 1 h prior to the 6, 12 or 24 h timepoints normalized BDNF expression for the corresponding timepoint (i.e., mRNA levels became indifferent from baseline). These results present for the first time a biphasic regulation of the neurotrophin system based on glucocorticoid rhythmicity, further indicating complex trophic responses to temporal hormonal mechanisms in the brain microenvironment